EP3453300B1

Movatterモバイル変換

Info

Publication number: EP3453300B1
Application number: EP18202105.5A
Authority: EP
Inventors: Michael J. Dooley; Nikolai Romanov; Marcus Williams; Joseph M. Johnson
Original assignee: iRobot Corp
Current assignee: iRobot Corp
Priority date: 2013-11-12
Filing date: 2014-11-11
Publication date: 2023-10-18
Anticipated expiration: 2034-11-11
Also published as: AU2014348883A1; EP2945521A1; CN107028564A; JP6165317B2; AU2014348883C1; JP2017080522A; AU2018203583A1; EP3453300A1; CN105120726A; AU2016259361B2; JP7214788B2; CN107028564B; CN108378786A; JP2019048130A; JP6440752B2; KR20160085815A; EP2945521A4; JP2023052443A; KR101880832B1; ES2703924T3

Description

TECHNICAL FIELD

This disclosure relates to floor cleaning using a cleaning pad.

BACKGROUND

Tiled floors and countertops routinely need cleaning, some of which entails scrubbing to remove dried in soils. Various cleaning implements can be used for cleaning hard surfaces. Most implements include a cleaning pad that may be removably attached to the implement. The cleaning pads may be disposable or reusable. In some examples, the cleaning pads are designed to fit a specific implement or may be designed for more than one implement.
Traditionally, wet mops are used to remove dirt and other dirty smears (e.g., dirt, oil, food, sauces, coffee, coffee grounds) from the surface of a floor. A person usually dips the mop in a bucket of water and soap or a specialized floor cleaning solution and rubs the floor with the mop. In some examples, the person may have to perform back and forth scrubbing movements to clean a specific dirt area. The person then dips the mop in the same bucket of water to clean the mop and continues to scrub the floor. Additionally, the person may need to kneel on the floor to clean the floor, which could be cumbersome and exhausting, especially when the floor covers a large area.
Floor mops are used to scrub floors without the need for a person go on their knees. A pad attached to the mop or an autonomous robot can scrub and remove solids from surfaces and prevents a user from bending over to clean the surface, which prevents a injuries to the user.
JP 2012 176279 A discloses an autonomous coverage robot comprising a chassis, a drive system, a vacuum assembly comprising a collection region engaging the cleaning surface and a suction region in fluid communication with the collection region, a collection volume for collecting waste removed by the vacuum assembly, a supply volume configured to hold a cleaning liquid, an applicator configured to dispense the cleaning liquid onto the cleaning surface, and a wetting element engaging the cleaning surface to distribute the cleaning liquid.
US 2009/281661 A1 discloses a robotic cleaner including a cleaning assembly for cleaning a surface and a main robot body. The main robot body houses a drive system to cause movement of the robotic cleaner and a microcontroller to control the movement of the robotic cleaner. The cleaning assembly is located in front of the drive system and a width of the cleaning assembly is greater than a width of the main robot body. A robotic cleaning system includes a main robot body and a plurality of cleaning assemblies for cleaning a surface.

SUMMARY

The present invention relates to a mobile floor cleaning robot as set out inclaim 1. Other embodiments are described in the dependent claims. A surface cleaning pad is described including an absorbent core containing fiber material which absorbs and retains liquid material, a liner layer (also herein throughout called a "wrap layer") in contact with and covering at least one side of the absorbent core, containing fiber material which retains and wicks liquid material through the liner layer. In embodiments, the cleaning pad is disposable or washable and reusable.
When apad 100 is damp, not enough fluid is present to lubricate the interface between the bottom surface of the pad and the floor surface. A fully wetted pad will ride on a layer of fluid while the pad is moving over a floor surface, but as the damp pad slowly absorbs fluid, the not fully wet, not fully lubricated, wrap layer will drag on the floor surface. In implementations, the spunbond or spunlace wrap layer is manufactured with hydrophilic fibers that minimize the surface area of the pad exposed to air between the pad and the floor surface. A wet pad would stick to the hydrophilic floor surface if the indentations or needle punches were not part of the wrap layer. Applying a surface texture to the spunbond or spunlace of the wrap layer, such as a herringbone indentation patter or a square grid indentation pattern, breaks the surface tension that would otherwise case a wet pad to stick to a wet floor surface.
In implementations of the pad, the liner layer includes meltblown abrasive fibers adhered to the side of the liner layer not in contact with the absorbent core; the pad described above where the meltblown fibers have a diameter of between about 0.1 µm and about 20 µm; the pad described above where the meltblown abrasive fibers cover between about 44 percent and about 75 percent of the surface of the liner layer; In implementations of the pad, the meltblown abrasive fibers cover between about 50% and about 60% of the surface of the liner layer. The meltblown layer provides the pad with the advantages of breaking surface tension that might otherwise cause the wet wrap layer to stick to a wet floor. By adding texture and topography to a floor facing surface of the pad, the meltblown layer prevents the pad from sticking or encountering high drag forces. The meltblown layer also provides the pad with surface texture for roughing up dirt and debris stuck or dried to a floor surface and loosening dirt and debris for absorption by the airlaid inner core of the pad. In implementations of the pad the meltblown abrasive fibers and the liner layer have a collective thickness of between about 0.5 mm (millimeter) and about 0.7 mm. In other words, the maximum overlapped thickness from the outer layer of the applied meltblown to the surface of the wrap layer is 0.7mm. In implementations of the pad, the wrap layer has a thickness of between about 0.5 mm and about 0.7mm. In implementations, the wrap layer has a Worldwide Strategic Partners (WSP) 10.1(05) nonwoven materials water absorption test specification value of about 600%; the pad described above where the pad increases in thickness by less than 30% after liquid material absorption. In implementations, the pad additionally contains one or more of a scent agent, cleaning agent, surfactant, foaming agent, glossing agent, chemical preservative, debris retention agent (such as DRAKESOL) and/or anti-bacterial agent. In implementations, the absorbent core comprises a first airlaid layer adhered to a second airlaid layer and the second airlaid layer is adhered to a third airlaid layer.
Fluid wicks between the three layers and is retained uniformly vertically throughout the stack of airlaid layers without leaking back onto a floor surface beneath the cleaning pad while downward force is applied to the pad. The surface tension the top and bottom surfaces of each airlaid layer helps retain wicked fluid within each layer such that as the top layer fully saturates, no fluid will leak down to the middle airlaid layer through the bottom surface 11b of the top airlaid layer, and as the middle airlaid layer fully saturates, no fluid will leak down to the bottom layer through the bottom surface of the middle (or second) layer.
In implementations, the pad soaks up 8-10 times its weight in fluid into a relatively rigid matrix of airlaid layers that does not deform in any dimension when fully wet, and fluid absorption is achieved through capillary wicking, not by compress-release drawing because robot to which the pad is attached exerts very light, low variability cycle weight, not a cycle of heavy human push down and draw back. Each of airlaid layer slows down penetration of wicked fluid to the next adjacent airlaid layer such that early cycles of fluid application do not lead to the pay quickly sopping up all the fluid that is applied to the floor surface. The vertical stack of airlaid layers provides a resistance to puddling at the bottom of the airlaid core comprising the three airlaid layers. Each of the of airlaid layers has its own puddle resisting bottom surface for preventing puddling of absorbed fluid all the way down at the bottom of the bottom surface of the bottom (or third) layer.
In implementations, the airlaid layers are of non-uniform hardness or density in the vertically direction such the outer top and bottom surfaces are harder than the interior of each layer. In embodiments, as a characteristic of the manufacturing process, the airlaid layers are of non-uniform surface density such that the outer top and bottom surfaces are smoother and less absorptive than the interior of each layer. By varying the surface density at the outer surfaces of each of the airlaid layer, the airlaid layers remain absorptive, wicking fluid into each airlaid layer without leaking back through the bottom surfaces. By incorporating three such airlaid layers into the absorptive core of the pad, the pad therefore has superior fluid retention properties over a pad having a single core of thickness equivalent to the three layer stacked core. The three airlaid layers provide at least triple the amount of surface tension for
In implementations of the pad, the three airlaid layers are adhered to each other by means of an adhesive material. In some implementations, the adhesive material is applied in at least two evenly spaced strips along the length of at least one side of an airlaid layer and covers not more than 10% of the surface area of the at least one side. In implementations, of the pad the adhesive material is sprayed on the length of at least one side of an airlaid layer and covers not more than 10% of the surface area of the at least one side. In implementations of the pad, at least one airlaid layer comprises a cellulose based textile material. In some implementations, at least one airlaid layer, and preferably all three airlaid layers, comprises wood pulp. In some implementations, one or more of the airlaid layers comprises biocomponent polymers, cellulose, and latex and the polymer is present in an amount up to about 15% by weight.
The fluid applicator applies fluid to a floor surface area in front of the cleaning pad and in the forward drive direction of the mobile robot, and the fluid is applied to a floor surface area previously occupied by the cleaning pad. In implementations, the previously occupied floor surface area is stored on a map accessible to the controller circuit. In implementations, fluid is applied to a floor surface area the robot has backed away from by a distance of at least one robot footprint length immediately prior to applying fluid so that the fluid is only applied to traversable floor and not to a wall, piece of furniture, carpet or other non- floor area that triggers a bump sensor (collision) switch or proximity sensor on the robot. In implementations, executing the cleaning routine further comprises moving the cleaning pad in a birdsfoot motion forward and backward along a center trajectory, forward and backward along a trajectory to a left side of and heading away from a starting point along the center trajectory, and forward and backward along a trajectory to a right side of and heading away from a starting point along the center trajectory. The robot drive comprises right and left drive wheels disposed on corresponding right and left portions of the robot body, and a center of gravity of the robot is positioned forward of the drive wheels, causing a majority of an overall weight of the robot to be positioned over the pad holder. Because the pad does not expand during fluid absorption, the weight of the robot remains positioned over the pad holder throughout the cleaning routine. The overall weight of the robot is distributed between the pad holder and the drive wheels at a ratio of 3 to 1. In implementations, the robot body and the pad holder both define substantially rectangular foot prints. Additionally, in implementations, the robot further includes a vibration motor disposed on a top portion of the pad holder. In some implementations, the robot further includes a toggle button for actuating the pad holder release mechanism and ejecting the pad. A backing layer on the pad engages with the pad holder, and the pad holder comprises raised protrusions positioned for aligning to and engaging with one or more shaped slots cut out of the backing layer along a peripheral edge of the backing layer. In some implementations, the pad holder comprises raised protrusions positioned for aligning to and engaging with one or more shaped slots cut out of the backing layer at a location other than along a peripheral edge.
A method of cleaning a surface with mobile floor cleaning robot is also described as set out in independent claim 12. Other embodiments are described in the dependent claims.
In some implementations, the robot includes a toggle button for actuating the pad holder release mechanism and ejecting the pad. In some implementations, the pad includes a backing layer for engaging with the pad holder and the pad holder comprises raised protrusions positioned for aligning to and engaging with shaped slots cut out of the backing layer.
One aspect of the disclosure provides a mobile floor cleaning robot having a robot body, a drive, a cleaning assembly, a pad holder, and a controller circuit. The robot body defines a forward drive direction. The drive supports the robot body to maneuver the robot across a floor surface. The cleaning assembly is disposed on the robot body and includes a pad holder, a reservoir, and a sprayer. The pad holder has a bottom surface configured to receive a cleaning pad and arranged to engage the floor surface, and the bottom surface has one or more raised protrusions extending therefrom.
The reservoir is configured to hold a volume of fluid, and the sprayer, which is in fluid communication with the reservoir, is configured to spray the fluid along the forward drive direction forward of the pad holder. The controller circuit communicates with both the drive system and the cleaning system and executes a cleaning routine. The controller circuit executes a cleaning routine that allows the robot to drive in the forward drive direction a first distance to a first location and then drive in a reverse drive direction, opposite the forward drive direction, a second distance to a second location. The cleaning routine allows the robot to spray fluid on the floor surface from the second location, in the forward drive direction forward of the pad holder but rearward of the first location. In this manner, the robot only applies fluid to traversable floor and not to a wall, piece of furniture, carpet or other non-floor area that triggers a bump sensor (collision) switch or proximity sensor on the robot. After spraying fluid on the floor surface, the cleaning routine allows the robot to drive in alternating forward and reverse drive directions while smearing the cleaning pad along the floor surface.
In some implementations, the robot includes a toggle button for actuating the pad holder release mechanism and ejecting the pad. In some implementations, the pad includes a backing layer for engaging with the pad holder and the pad holder comprises raised protrusions positioned for aligning to and engaging with shaped slots cut out of the backing layer.
Another aspect of the disclosure provides a mobile floor cleaning robot that includes a robot body, a drive, and a cleaning assembly. The robot body defines a forward drive direction. The drive system supports the robot body to maneuver the robot across a floor surface. The cleaning assembly is disposed on the robot body and includes a pad holder and an orbital oscillator. The pad holder is disposed forward of the drive wheels and has a top portion and a bottom portion. The bottom portion has a bottom surface arranged within between about 0.5 cm and about 1.5 cm of the floor surface and receives a cleaning pad. The bottom surface of the pad holder includes at least 40 percent of a surface area of a footprint of the robot and has one or more raised protrusions extending therefrom. The orbital oscillator is disposed on the top portion of the pad holder and has an orbital range less than 1cm. The pad holder is configured to permit more than 80 percent of the orbital range of the orbital oscillator to be transmitted from the top of the held cleaning pad to the bottom surface of the held cleaning pad.
The one or more protrusions assist with aligning the pad to the pad holder and retaining the pad securely in place during oscillation of the orbital oscillation while the robot moves in a back and forth scrubbing cleaning pattern. In implementations, the pad holder includes a release mechanism configured to eject the pad from the bottom surface of the pad holder upon actuation of the release mechanism such that a user need not touch a used, dirty pad to dispose of it. Actuating the release mechanism while holding the robot above a trash container ejects the pad from the pad holder into the trash container therebeneath.
In some examples, the robot moves in a birdsfoot motion forward and backward along a center trajectory, forward and backward along a trajectory to the left of and heading away from a starting point along the center trajectory, and forward and backward along a trajectory to the right of and heading away from a starting point along the center trajectory.
In some examples, the cleaning pad has a top surface attached to the bottom surface of the pad holder and the top of the pad is substantially immobile relative to the oscillating pad holder.
In some examples, the pad holder has a release mechanism configured to eject the pad from the bottom surface of the pad holder upon actuation of a release mechanism. In some examples, robot includes a toggle button for actuating the pad holder release mechanism and ejecting the pad. In some examples, the pad includes a backing layer for engaging with the pad holder and the pad holder comprises raised protrusions positioned for aligning to and engaging with shaped slots cut out of the backing layer.
The cleaning assembly may further include at least one post disposed on the top portion of the pad holder sized for receipt by a corresponding aperture defined by the robot body. The at least one post may have a cross sectional diameter varying in size along its length. Additionally or alternatively, the at least one post may include a vibration dampening material.
In some implementations, the cleaning assembly further includes a reservoir to hold a volume of fluid, and a sprayer in fluid communication with the reservoir. The sprayer is configured to spray the fluid along the forward drive direction forward of the pad holder. The reservoir may hold a fluid volume of about 200 milliliters.
The drive may include a drive body, which has forward and rearward portions, and right and left motors disposed on the drive body. The right and left drive wheels are coupled to the corresponding right and left motors. The drive may also include an arm that extends from the forward portion of the drive body. The arm is pivotally attachable to the robot body forward of the drive wheels to allow the drive wheels to move vertically with respect to the floor surface. The rearward portion of the drive body may define a slot sized to slidably receive a guide protrusion that extends from the robot body. In one implementation, the cleaning pad disposed on the bottom surface of the pad holder body absorbs about 90% of the fluid volume held in the reservoir. The cleaning pad has a thickness of between about 6.5 millimeters and about 8.5 millimeters, a width of between about 80 millimeters and about 68 millimeters, and a length of between about 200 millimeters and about 212 millimeters.
In some examples, a method includes driving a first distance in a forward drive direction defined by the robot to a first location, while moving a cleaning pad carried by the robot along a floor surface supporting the robot. The cleaning pad has a center area and lateral areas flanking the center area. The method further includes driving in a reverse drive direction opposite the forward drive direction, a second distance to a second location while moving the cleaning pad along the floor surface In this manner, the robot only applies fluid to traversable floor and not to a wall, piece of furniture, carpet or other non- floor area that triggers a bump sensor (collision) switch or proximity sensor on the robot. The method also includes applying fluid to an area on the floor surface substantially equal to a footprint area of the robot and forward of the cleaning pad but rearward of the first location. The method further includes returning the robot to the area of applied fluid in a movement pattern that moves the center and lateral portions of the cleaning pad separately through the area to moisten the cleaning pad with the applied fluid.
In some examples, the method includes driving in a left drive direction or a right drive direction while driving in the alternating forward and reverse directions after spraying fluid on the floor surface. Applying fluid on the floor surface may include spraying fluid in multiple directions with respect to the forward drive direction. In some examples, the second distance is at least equal to the length of a footprint area of the robot.
In still yet another aspect of the disclosure, a method of operating a mobile floor cleaning robot includes driving a first distance in a forward drive direction defined by the robot to a first location while smearing a cleaning pad carried by the robot along a floor surface supporting the robot. The method includes driving in a reverse drive direction, opposite the forward drive direction, a second distance to a second location while smearing the cleaning pad along the floor surface. The method also includes spraying fluid on the floor surface in the forward drive direction forward of the cleaning pad but rearward of the first location. The method also includes driving in an alternating forward and reverse drive directions while smearing the cleaning pad along the floor surface after spraying fluid on the floor surface.
In some implementations, the method includes spraying fluid on the floor surface while driving in the reverse direction or after having driven in the reverse drive direction the second distance. In implementations, the method includes driving in a left drive direction or a right drive direction while driving in the alternating forward and reverse directions after spraying fluid on the floor surface. Spraying fluid on the floor surface may include spraying fluid in multiple directions with respect to the forward drive direction. In some implementations, the second distance is greater than or equal to the first distance.
The mobile floor cleaning robot may include a robot body, a drive, a pad holder, a reservoir, and a sprayer. The robot body defines the forward drive direction and has a bottom portion. The drive system supports the robot body and maneuvers the robot over the floor surface. The pad holder is disposed on the bottom portion of the robot body and holds the cleaning pad. The pad holder has a release mechanism configured to eject the pad upon actuation, and the pad further comprising a backing layer for engaging with the pad holder. The pad holder has a bottom surface having raised protrusions extending therefrom and the raised protrusions are sized, shaped and positioned to align to and engage with slots cut out of the backing layer.
The reservoir is housed by the robot body and holds a fluid (e.g., 200ml). The sprayer, which is also housed by the robot body, is in fluid communication with the reservoir and sprays the fluid in the forward drive direction forward of the cleaning pad. The cleaning pad disposed on the bottom portion of the pad holder may absorb about 90% of the fluid contained in the reservoir. In some examples, the cleaning pad has a width of between about 80 millimeters and about 68 millimeters and a length of between about 200 millimeters and about 212 millimeters. The cleaning pad may have a thickness of between about 6.5 millimeters and about 8.5 millimeters. The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below.
In some implementations, the fluid applicator is a sprayer that includes at least two nozzles each distributing the fluid evenly across the floor surface in two strips of applied fluid. The two nozzles are each configured to spray the fluid at an angle and distance different than another nozzle. In some implementations, the two nozzles are vertically stacked in a recess in the fluid applicator and angled from horizontal and spaced apart from one another such that one nozzle sprays relatively longer lengths of fluid forward and downward to cover an area in front of the robot with a forward supply of applied fluid 173a, and the other nozzle sprays relatively shorter lengths fluid forward and downward to leave a rearward supply of applied fluid on an area in front of but closer to the robot than the area of applied fluid dispensed by the top nozzle.
In implementations, the nozzle or nozzles dispense fluid in an area pattern that extends one robot width and at least one robot length in dimension. In some implementations, the top nozzle and bottom nozzle apply fluid in two distinct spaced apart strips of applied fluid that do not extend to the full width of the robot such that the pad passes through the outer edges of the strips of applied fluid in forward and backward angled scrubbing motions as described herein. In embodiments, the strips of applied fluid cover a width of 75-95% of the robot width and a combined length of the robot length. In implementations, the strips of applied fluid may be substantially rectangular shaped or ellipse shaped. In implementations, the nozzles complete each spray cycle by sucking in a small volume of fluid at the opening of the nozzle so that no fluid leaks from the nozzle following each instance of spraying.
In some implementations, the pad includes a cardboard backing layer adhered to the top surface of the pad. The cardboard backing layer protrudes beyond the longitudinal edges of the pad and the protruding longitudinal edges of the cardboard backing layer attach to the pad holder of the robot. In one embodiment, the cardboard backing layer is between 0.02 inch and 0.03 inch thick (0.05 cm and 0.762 cm thick), between 68 and 72 mm wide and between 90-94mm long. In one embodiment, thecardboard backing layer 85 is approximately 0.066 cm (0.026 inch) thick, 70mm wide and 92mm long. In one embodiment, the cardboard backing layer is coated on both sides with a water resistant coating, such as wax or polymer or a combination of water resistant materials, such as wax/polyvinyl alcohol/polyamine, and the cardboard backing layer does not disintegrate when wetted.
In implementations, the pad is a disposable pad. In other examples, the pad is a reusable microfiber cloth pad having the same absorptive characteristics as those described herein with regard to embodiments. In examples having a washable, reusable microfiber cloth, the top surface of the cloth includes a secured stiff backing layer shaped and positioned like the cardboard backing layer described with regard to embodiments. The stiff backing layer is made of heat resistant, washable material that withstands being machine dried without melting or degrading the backing. The stiff backing layer is dimensioned and has cutouts as described herein for interchangeable use with the embodiment of the pad holder described with regard to embodiments herein.
In other examples, the pad is a disposable dry cloth and comprises a single layer of needle punched spunbond or spunlace material having exposed fibers for entrapping hair. The dry pad further comprises a chemical treatment that adds a tackiness characteristic to the pad for retaining dirt and debris. In one embodiment, the chemical treatment is a material such as that marketed under the trade name DRAKESOL.
In some examples, the pad is secured to an autonomous robot through a pad holder attached to the robot. A pad release mechanism adjusts to an up or pad-secure position. The pad release mechanism includes a retainer, or lip, that holds the pad securely in place by grasping protruding longitudinal edges of a cardboard backing layer secured to the top of the pad. In examples, the tip or end of the pad release mechanism includes a moveable retention clip and an eject protrusion that slides up through a slot or opening in the pad holder, and is pushed through the slot into a down position to release the secured pad by pushing down on the attached cardboard backing layer.
Other aspects, features, and advantages will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1A is an exploded view of an exemplary cleaning pad.
FIG. 1B is an exploded view of the wrap layer of the exemplary cleaning pad ofFIG. 1.
FIG 1C is a section view of an exemplary cleaning pad.
FIG 1D is a section view of an exemplary cleaning pad where the airlaid layers include superabsorbent polymers.
FIG. 2A is a schematic view of an exemplary arrangement of operations for a spunlace process.
FIG. 2B is a perspective view of the hydroentaglement process for making the spunlace layer used in the exemplary cleaning pad.
FIG. 3 is a perspective view of a device for making the abrasive meltblown layer used in the exemplary cleaning pad.
FIG. 4 is a perspective view of an autonomous mobile robot for cleaning using the exemplary cleaning pad.
FIG. 5 is a perspective view of a mop using the exemplary cleaning pad.
FIG. 6 is a bottom view of an exemplary cleaning pad.
FIG. 7 is a schematic view of an exemplary arrangement of operations for constructing a cleaning pad.
FIG. 8A is a perspective view of an exemplary cleaning pad.
FIG. 8B is an exploded perspective view of the exemplary cleaning pad ofFIG. 8A.
FIG. 8C is a top view of an exemplary cleaning pad.
FIG. 8D is a bottom view of an exemplary attachment mechanism for the pad as described herein.
FIG. 8E is a side view of an exemplary attachment mechanism for a pad as described herein in a secure position.
FIG. 8F is a top view of an exemplary attachment holder for the pad as described herein.
FIG. 8G is a cut away side view of an exemplary attachment mechanism for the pad as described herein in a release position.
FIGS. 9A-9C are top views of an exemplary autonomous mobile robot as it sprays a floor surface with a fluid.
FIG. 9D is a top view of an exemplary autonomous mobile robot as it scrubs a floor surface.
FIG. 9E is a bottom view of an exemplary cleaning pad.
FIG. 9F is a top view of an exemplary autonomous mobile robot as it scrubs a floor surface.
FIG. 9G is a top view of an exemplary autonomous mobile robot as it scrubs a floor surface.
FIG. 10 is a schematic view of the robot controller of the exemplary autonomous mobile robot ofFIG. 4.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Referring toFIGS. 1A,1B and1C, in some implementations, adisposable cleaning pad 100 includes a plurality of absorbentairlaid layers 101, 102, 103 stacked, optionally bonded to one another, and enwrapped by anouter non-woven layer 105 which can have an abrasivemeltblown elements 106 disposed thereon. In some examples, thecleaning pad 100 includes one or moreairlaid layers 101, 102, 103. As shown, thecleaning pad 100 includes first, second and thirdairlaid layers 101, 102, 103, but additional airlaid layers are possible as well. The number ofairlaid layers 101, 102, 103 may depend on the amount of cleaningfluid 172 thecleaning pad 100 is required to absorb. Eachairlaid layer 101, 102, 103 has atop surface 101a, 102a, 103a and abottom surface 101b, 102b, 103b. Thebottom surface 101b of the first (or top)airlaid layer 101 is disposed on thetop surface 102a of thesecond airlaid layer 102, and thebottom surface 102b of thesecond airlaid layer 102 is disposed on thetop surface 103a of the third (or bottom)airlaid layer 103. Fluid wicks between the three layers and is retained uniformly vertically throughout the stack of airlaid layers without leaking back onto a floor surface beneath thecleaning pad 100 while downward force is applied to thepad 100. In implementations, thepad 100 retains 90 percent of fluid applied to afloor surface 10 and under 1 pound of force, thepad 100 does not leak absorbed fluid back onto thefloor surface 10. The surface tension the top and bottom surfaces of each airlaid layer helps retain wicked fluid within each layer such that as thetop layer 101 fully saturates, no fluid will leak down to themiddle airlaid layer 102 through thebottom surface 101b of thetop airlaid layer 101, and as themiddle airlaid layer 102 fully saturates, no fluid will leak down to the bottom layer through thebottom surface 102b of the middle (or second)layer 102.
In implementations, thepad 100 soaks up 8-10 times its weight into a relatively rigid matrix ofairlaid layers 101, 102, 103, and fluid absorption is achieved through capillary wicking, not by compress-release drawing becauserobot 400 to which the pad is attached exerts very light, low variability cycle weight, not a cycle of heavy human push down and draw back. Each ofairlaid layer 101, 102, 103 slows down penetration of wicked fluid to the nextadjacent airlaid layer 101, 102, 103, such that early cycles of fluid application do not lead to the pay quickly sopping up all the fluid that is applied to the floor surface. The vertical stack ofairlaid layers 101, 102, 103 provides a resistance to puddling at the bottom of the airlaid core comprising the threeairlaid layers 101, 102, 103. Each of the ofairlaid layers 101, 102, 103 has its own puddle resistingbottom surface 101b, 102b, 103b for preventing puddling of absorbed fluid all the way down at the bottom of thebottom surface 103b of the bottom (or third)layer 103b.
In embodiments, theairlaid layers 101, 102, 103 are of non-uniform hardness or density in the vertically direction such the outer top and bottom surfaces are harder than the interior of each layer. In embodiments, theairlaid layers 101, 102, 103 are of non-uniform surface density such that the outer top and bottom surfaces are smoother and less absorptive than the interior of each layer. By varying the surface density at theouter surfaces 101b, 102b, 103b of each of theairlaid layer 101, 102, 103, theairlaid layers 101, 102, 103 remain absorptive, wicking fluid into each airlaid layer without leaking back through the bottom surfaces 101b, 102b, 103b. By incorporating three suchairlaid layers 101, 102, 103 into the absorptive core of thepad 100, thepad 100 therefore has superior fluid retention properties over a pad having a single core of thickness equivalent to the three layer stacked core. The threeairlaid layers 101, 102, 103 provide at least triple the amount of surface tension for retaining wicked fluid in the absorptive cores of each of theairlaid layers 101, 102, 103.
Awrap layer 104 wraps around theairlaid layers 101, 102, 103 and prevents theairlaid layers 101, 102, 103 from being exposed. Thewrap layer 104 includes a wrap layer 105 (e.g., a spunlace layer) and anabrasive layer 106. Thewrap layer 105 is wrapped around the first, second, and thirdairlaid layers 101, 102, 103. Thewrap layer 105 has atop surface 105a and abottom surface 105b. Thetop surface 105b of thewrap layer 105 covers theairlaid layers 101, 102, 103. Thewrap layer 105 may be a flexible material having natural or artificial fibers (e.g., spunlace or spunbond). Theabrasive layer 106 is disposed on thebottom side 105b of thewrap layer 105. Fluid applied to afloor 10 beneath thecleaning pad 100 transfers through thewrap layer 105 and into theairlaid layers 101, 102, 103. Thewrap layer 105 wrapped around theairlaid layers 101, 102, 103 is a transfer layer that prevents exposure of raw absorbent material in the airlaid layers. If thewrap layer 105 were too absorbent, thepad 100 would be suctioned onto afloor 10 and difficult to move. A robot, for example, may be unable to overcome the suction force while trying to move thecleaning pad 100 across thefloor surface 10. Additionally, thewrap layer 105 picks up dirt and debris loosened by the abrasionouter layer 106 and may leave a thin sheen of a cleaningfluid 172 on thesurface 10 that air dries without leaving streak marks on thefloor 10. The thin sheen of cleaning solution is between 1.5 and 3.5 ml/square meter and dries in a duration no longer than three minutes, and preferably dries within between about 2 minutes and 3 minutes.
Thedisposable cleaning pad 100 relies on capillary action (also known as wicking) to absorb fluid on afloor surface 10. Capillary action occurs when a liquid is able to flow in narrow spaces without external forces, such as gravity. Capillary action allows a fluid to move within spaces of a porous material due to forces of adhesion, cohesion, and surface tension. Adhesion of the fluid to the walls of a vessel will cause an upward force on the liquid edges and result in meniscus, which turns upwards. The surface tension acts to hold the surface intact. Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces between the fluid molecules.
In some examples, theairlaid layers 101, 102, 103 are a textile-like material made from fluff pulp, which is a type of wood pulp/chemical pulp made from long fiber softwoods. Chemical pulp is created by applying heat to a combination of wood chips and chemical materials in a large container to break down the lignin (organic substance that binds the cells in the wood). The textile-like material that is made from fluff pulp may be very bulky, porous, soft, and has good water absorption properties. The textile-like material does not scratch the floor surface, maintains its strength even when it is wet, and may be washed and reused.
Referring toFIG. 1D, in some implementations, theairlaid layers 101, 102, 103 include an absorbent layer of a mixture of air-laid paper and superabsorbent polymers 108 (e.g., sodium polyacrylate) for wetness. Polymers include plastic and rubber materials, which are mainly organic compounds that are chemically based on carbon, hydrogen, and other nonmetallic elements. Polymers generally have larger molecular structures, which typically have low densities and may be extremely flexible. Superabsorbent polymers 108 (also known as slush powder) absorb and retain large amounts of a fluid in comparison to their own mass. The ability of thesuperabsorbent polymers 108 to absorb water depends on the ionic concentration of the aqueous solution. Asuperabsorbent polymer 108 may absorb up to 500 times its weight in deionized and distilled water (30-60 times its volume) and may become 99.9% liquid. The absorbency of thesuperabsorbent polymers 108 drops significantly to about 50 times its weight when put into a 0.9% saline solution. The valence cations in the saline solution prevent thesuperabsorbent polymer 108 from bonding with the water molecules. Thesuperabsorbent polymers 108 may expand causing thecleaning pad 100 to expand as well.Various implements 400, 500 may use thecleaning pad 100, and, in some examples, theimplements 400, 500 may not support acleaning pad 100 that may expand. For example, expansion of thepad 100 may disturb the physics of a compact,lightweight robot 400, causing thecompact robot 400 to tilt upward and apply less force to thepad 100 for debris removal from thefloor 10. Therefore, lesssuperabsorbent polymers 108 may be used to meet a cleaning pad absorbency requirement. In one embodiment, thepad 100 may contain pockets in a middle section along the pad length that allow superabsorbent polymers to expand into those pockets and allow the pad to maintain a constant thickness as the superabsorbent polymers expand.
In some implementations, theairlaid layers 101, 102, 103 include a cellulose pulp nonwoven material that is through air bonded with a bicomponent fiber. In some examples, fibers of wood pulp cellulose are thermally bonded with bicomponent polyethylene, and/or polypropylene, which has a low melting point. This mixture forms a solid absorbent core that holds its formed shape and that evenly distributes absorbed fluid, preventing cleaning fluid from pooling at the lowest point in the layer and preventing additional fluid accumulation. The airlaid layers 101, 102, 103 may be manufactured from a bleached wood pulp that looks like a thick layer of cardboard. The pulp enters a hammer mill having blades on a rotor that strikes the thick layer of pulp and devibrates it into individual fibers. The individual fibers enter a distributor having a screen rotor that looks like a flour sifter. The fibers are formed into a sheet on another screen having an applied vacuum underneath, at which stage the sheet is blended with a sheet of bicomponent fiber. Blown hot air melts the bicomponent to bond with the airlaid.
The airlaid layers are situated so as to distribute the absorbed liquid substantially uniformly throughout the core, without puddling of liquid anywhere in the core layers (expand?). Themobile robot 400 sprays fluid 172 in front of the robot uniformly and thepad 100 picks up the appliedsolution 173a, 173b in an even distribution along its length when traveling forward. In one embodiment, theairlayed layers 101, 102, 103 are bonded with spray adhesive applied evenly over the surface of theairlaid layer 101, 102, 103. In one embodiment, the adhesive is polyolefin and is applied in a thin, uniform manner to get reliable adhesion without creating ridges and stiff areas. The spray adhesive also creates a uniformly bonded surface interface, allows fluid to wick into theairlaid layers 101, 102, 103 without a large mechanical barrier (for example, stitches, or relatively large impermeable glue patches or ridges) and this uniformly bonded surface interface betweenairlaid layers 101, 102, 103 prevents puddling between thelayers 101, 102, 103.
A very small amount of acrylic latex bonding agent may be sprayed sparingly on both the surfaces to bind the external layers and to minimize sloughing and help reduce linting. Linting is a condition that occurs when fine ravelings of cotton, linen, or fiber are apparent on an object or fabric. The airlaid layers 101, 102, 103 may include 15% of biocomponent polymers, 85 % cellulose, and latex at the top to eliminate linting.
Thewrap layer 105 may be of any material that is thin and absorbs fluid. In addition, thewrap layer 105 may be smooth to prevent scratching thefloor surface 10. In some implementations, thecleaning pad 100 may include one or more of the following cleaning agent constituents butoxypropanol, alkyl polyglycoside, dialkyl dimethyl ammonium chloride, polyoxyethylene castor oil, linear alkylbenzene sulfonate, glycolic acid - which for example serve as surfactants, and to attack scale and mineral deposits, among other things; and including scent, antibacterial or antifungal preservatives.
In some examples, thewrap layer 105 is a spunlace nonwoven material. Spunlace may also be known as hydroentangling, water entangling, jet entangling or hydraulic needling. Spunlace is a process of entangling a web of loose fibers typically formed by a card on a porous belt or moving perforated or patterned screen to form a sheet structure by subjecting the fibers to multiple passes of fine high-pressure water jets. The hydroentangling process enables formation of specialty fabrics by adding fibrous materials, such as tissue paper, airlaid, spunlace and spunbond nonwovens to composite non-woven webs. These materials offer performance advantages needed for many wipe applications due to their improved performance or cost structure.
Referring toFIGS. 2A and2B, thespunlace process 200 includes a precursor web forming process 202a. The precursor web is usually made of staple textile-like fibers. These webs can be single fiber webs or made of many different fiber blends. The typical four fibers of choice are polyester, viscose, polypropylene and cotton. Variants of each of these fibers may also be used, such as organic cotton, as well as Lyocell material, and Tencel rayon. PLA (polylactic acid) fibers which are biodegradable can also be used.
The precursor web forming process 202a may include forming airlaid cards, which may be used to provide a more isotropic web as a result of higher transversal orientation of the fibers. Carding is a method of making thin webs of parallelized fibers. Higher bulk may also be obtained by using this type of carding system. Once the web of staple fibers is formed, a second layer of fibers may be placed on top of this base by air forming cellulose fibers, or by "laminating" a preformed nonwoven web, such as tissue, spunlace or spunbond. In some examples, spunbond isisnonwoven material is combined is combined with airlaid layers and thus the resulting fabric eliminates the carding step of hydroentangling continuous fibers with cellulose pulp fibers. This fibrous composition then goes under afiber entangling process 204 constituted of rows of high-pressure water jets 210 that duplicate the conventional mechanical needling process and intertwine the fibers individually, so that they become entangled forming aweb 212.
Thespunlace process 200 includes applying afiber entangling process 204 to the fibrous composition. Thefiber entangling process 204 includes jetting water from rows of high-pressure water jets 210 to duplicate the conventional mechanical needling process and intertwine the fibers individually so that they become entangled, forming aweb 212. The web 212 (after going through the web forming and carding process 202) is placed on aconveyor belt 214 rotated by two ormore pulleys 216. During and/or after each water injection process theweb 212 goes through drums withsuction 218 that suck the water out of the fiber and allow the fiber to keep moving to the next high-pressure water jets 210.
The consolidatednonwoven substrate 215 is subsequently dried through air-dryers in anair dryer process 206 and then wound in a windingprocess 208.
Thewrap layer 105 can be printed on as well as thermally embossed. Embossing and debosing are processes for creating raised or recessed designs in fabric or other material. A relatively lower melt fiber, such as polypropylene, may be used to achieve better thermal embossing. The coefficient of friction of thewrap layer 105 varies based on surface type and wetness. In on embodiment, adry pad 100 moving on glass has a coefficient of friction of about 0.4 to about 0.5, and wet on tiles has a coefficient of friction of about 0.25 to about 0.4. Thewrap layer 105 may include hydroembossing, which imparts three dimensional images on the fabric. Hydroembossing is generally less expensive than thermal bonding. In one example, thewrap layer 105 is embossed with a herringbone pattern. Thewrap layer 105 wrapped around a series ofairlaid layers 101, 102, 103 enables the formation of an absorbent core that locks in absorbed fluid. The layering of airlaid core layers 101, 102, 103 enables capillary action and retention throughout the combined core and within each individual layer 101,102, 103. Furthermore, theairlaid layers 101, 102, 103 making up the core of the pad retain their shape while distributing fluid evenly throughout each fluid retention layer and preventing pooling that would prohibit additional absorption.
Theabrasion meltblown layer 106 includesmeltblown fibers 107, which are fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into converging high velocity gas streams that cut the filaments of molten thermoplastic material to reduce their diameters. Thus, themeltblown fibers 107 are carried by the high velocity gas stream and placed on a surface that collects the fibers, therefore forming a web of randomly distributedmeltblown fibers 107.
In some examples, theabrasion meltblown layer 106 is a layer ofmeltblown fibers 107 that provide a rough surface. Themeltblown fibers 107 are formed by a meltblown process 300 (seeFIG. 3) at high throughput, which creates spittle, or hair like fibers, that are formed by a polymer drooled from the die orifices due to temperature and other conditions in which it is run. Theabrasive layer 106 is formed on top of the wrap layer 105 (e.g., another meltblown layer, a spunbond layer, or a spunlace layer). Thewrap layer 105 may be a herring bone hydroembossed nonwoven material, which is made of a ratio of viscose (rayon) fibers blended with polyester fibers. In some examples, theabrasion meltblown layer 106 has a basis weight (also known as grammage) equal to 55g/m² (grams per square meter). Thewrap layer 105 may have a basis weight of between about 30 gsm (grams per square meter) and about 65 gsm. In other examples, the wrap layer may have a basis weight of between about 35-40 gsm. Basis weight is a measurement used in both the fabric and paper industries to measure the mass of the product per unit of area. In an embodiment, thewrap layer 105 is a hydroentangled spunbond or spunlace material formed with indentations (not show) therein that allow fluid and suspended dirt to pass more directly through to theairlaid layers 101, 102, 103 and reduce the amount of cohesive suction between thewrap layer 105 and thefloor surface 10 when thepad 100 is wet. In one embodiment, the indentations are in a herringbone pattern. In another embodiment, the indentations form a grid of squares sized and spaced to be between 0.50 and 1.0 mm square and spaced apart in a grid formation by a length of 2.0-2.5 mm. In one embodiment, the indentations are sized and spaced to be 0.75mm square and spaced apart in a grid formation by a length of 2.25mm. In another embodiment, thewrap layer 105 is a spunbond or spunlace material having needle-punched holes therein for improving the wicking ability of thewrap layer 105 and decreasing the cohesion between thewet wrap layer 105 and thefloor surface 10. The herringbone, square and needle punched indentations prevent a negative pressure from generating at the outside of the wrap layer as fluid evaporates and/or wicks from the back of the liner. Without free movement inside thewrap layer 105 or some texture on thewrap layer 105, fluid applied to thefloor surface 10 cannot replace the wicked fluid, and that causes suction between thepad 100 and the floor. Combining a low density spunbond or spunlace material of 35-40 gsm with a surface texture in the form of hydroembossed indentations, surface textures and patterns (such as herringbone), or needle punched indentations or holes prevents suction between the pad and the floor. Themeltblown layer 105 further assists with preventing this this suction force.
Additionally, when apad 100 is damp, not enough fluid is present to lubricate the interface between the bottom surface of the pad and thefloor surface 10. A fully wettedpad 100 will ride on a layer of fluid while therobot 400 is moving, but as thedamp pad 100 slowly absorbs fluid, the not fully wet, not fully lubricated,wrap layer 106 will drag on thefloor surface 10. In implementations, the spunbond orspunlace wrap layer 105 is manufactured with hydrophilic fibers that minimize the surface area of thepad 100 exposed to air between thepad 100 and thefloor surface 10. Awet pad 100 would stick to thehydrophilic floor surface 10 if the indentations or needle punches were not part of thewrap layer 100. Applying a surface texture to the spunbond or spunlace of thewrap layer 105 breaks the surface tension that would otherwise case awet pad 100 to stick to awet floor surface 10.
The weight of theabrasion meltblown layer 106 is such that theabrasion meltblown layer 106 acts as an absorbing layer and allows for fluid to be absorbed through themeltblown layer 106 and be retained by theairlaid layer 101, 102, 103. In some examples, themeltblown layer 106 covers about 60 to about 70% of the surface area of thespunlace wrap layer 105 and in other examples, themeltblown layer 106 covers about 50-60% of the surface area of a spunbond orspunlace wrap layer 105.
Themeltblown fibers 107 may have different arrangements and configurations on thespunlace wrap layer 105. In some examples, themeltblown fibers 107 are randomly arranged on thewrap layer 105. Themeltblown fibers 107 may be arranged in one ormore sections 109a-e on acleaning surface 109. Thecleaning surface 109 is a bottom surface of thecleaning pad 100 that is in contact with thefloor surface 10. The one ormore sections 109a-e on thecleaning surface 109 have a covered ratio between the meltblownabrasive fibers 107 and thewrap layer 105 greater than 50%. The meltblown layer provides the pad with the advantages of breaking surface tension that might otherwise cause the wet wrap layer to stick to a wet floor. By adding texture and topography to a floor facing surface of the pad, the meltblown layer prevents the pad from sticking or encountering high drag forces. The meltblown layer also provides the pad with surface texture for roughing up dirt and debris stuck or dried to a floor surface and loosening dirt and debris for absorption by the airlaid inner core of the pad.
As shown inFIG. 3, themeltblown process 300 is a process that extrudes and draws molten polymer resins with a heated,high velocity air 310 to form fibers orfilaments 107. The fibers/filaments 107 are cooled and are then formed into aweb 106 on top of a movingscreen 320. Thisprocess 300 is similar to spunbond, but thefibers 107 generated here are much finer and range in the 0.1 to 20 µm (e.g., 0.1 - 5 µm) diameter range. Meltblowing is also considered a spunmelt or spunlaid process. The process shown inFIG. 3 shows an extrusion die 312 (beam) that extrudes the melt blown polypropylene fibers into a continuous porous conveyor to form thenonwoven web 106. It is made up of six major components: the extruder, metering pump, extrusion die, web forming, web consolidation and winding. Other processes are possible as well.
There are two basic die designs 312 used with the meltblown technology, the single row die and the multi-row die. The key difference between these two designs is the amount of air that is used as well as the throughput of the die. With the multi-row die, much greater throughput may be achieved. Multi-row dies usually have two to eighteen rows of holes and approximately three hundred holes per inch, while the conventional single row dies have twenty-five to thirty-five holes per inch. Either diedesign 312 may be used to form themeltblown fibers 107. Throughput for this process is much less than the 200+ kg/hr/meter (kilograms per hour per meter) obtained for spunbond or spunlace with its much larger fiber diameters. Conventional dies basically can extrude 70 to 90 kg/hr/meter, while the multi-row die can achieve about 160kg/hr/meter.
In some implementations, themeltblown fibers 107 have a diameter of between about 0.1 µm and about 5 µm with a mean of about 2.5 µm. Throughput and air flows have the greatest impact at reducing the fiber diameter, with melt and air temperatures and distance of the die from the forming table have less of an impact. Optimizing the process variables and using metallocene polypropylene may yield meltblown webs with mean fiber diameters in the range of 0.3 to 0.5 µm with maximum fiber diameters of less than 3µm. Awrap layer 104 withmeltblown fibers 107 of this size can provide a barrier against fluid leakage from thecleaning pad 100 by providing very high hydrohead webs with excellent breathability. Themeltblown fibers 107 may be created using homopolymer polypropylene; however, several other resins can be extruded by the meltblown process as well, such as polyethylene, polyester, polyamides and polyvinyl alcohols. In some implementations, themeltblown layer 106 is formed from polylactic acids (PLA), a biodegradable nonwoven.
In some examples, theairlaid layers 101, 102, 103, theabrasion layer 104 and the wrap layer 104 (i.e., the cleaning pad 100) have a combined width W_T of between about 68 millimeters and about 80 millimeters and a combined length (not shown) of between about 200 millimeters and about 212 millimeters. In some examples, thecleaning pad 100 including theairlaid layers 101, 102, 103, theabrasion layer 104 and thewrap layer 105 have a combined thickness T_T of between 6.5 millimeters and about 8.5 millimeters. Additionally, or alternatively, theairlaid layers 101, 102, 103 have a combined airlaid width (W_A1 + W_A2 + W_A3) of between 69 millimeters and about 75 millimeters and a combined airlaid length (L_A1 + L_A2 + L_A3) of between about 165 millimeters and about 171 millimeters. Thecleaning pad 100 withstands pressure being applied to it by an implement 400, 500 (e.g., robot or mop), since an implement 400, 500 will cause back and forth movement of thecleaning pad 100 mimicking a scrubbing action as therobot 400 traverses thefloor surface 10.
In some implementations, as thecleaning pad 100 is cleaning afloor surface 10, it absorbs cleaningfluids 172 applied to thefloor surface 10. Thecleaning pad 100 may absorb enough fluid without changing its shape. Therefore, where thecleaning pad 100 is used along with acleaning robot 400, thecleaning pad 100 has substantially similar dimensions before cleaning thefloor surface 10 and after cleaning thefloor surface 10. Thecleaning pad 100 may increase in volume when it absorbs fluids. In some examples, the thickness of the cleaning pad T_T increases by less than 30% after fluid absorption.

In some implementations, thewrap layer 104 has the specifications listed in Table 1 below:

Table 1

Wrap Layer
Characteristic	Unit	Average Value	Tolerance	Test Method
Weight	g/m²	55	+/- 10%	ASTM D3776M-09A
Thickness	mm	0.6	0.55-0.65	WSP 120.6
Tensile Strength (DRY)	N/2.54cm (MD)	50	> 40	ASTM D5034-09
Tensile Strength (DRY)	N/2.54cm (CD)	25	> 20	ASTM D5034-09
Elongation at break (DRY)	% (MD)	45	25-65	ASTM D5034-09
Elongation at break (DRY)	% (CD)	90	65 - 115	ASTM D5034-09
Water absorption	%		600	> 500	WSP 10.0 (05)
Abrasion resistance	Visual at 80 cycles	OK	No visible degradation	-

Meltblown Abrasive
Covered surface ratio	%	50	44 - 57	-
Scrubbing fiber average size	µm	N/A	8µm - 20µm	-

ASTM D3776M-09A and ASTM D5034-09 are standardized tests from the American Society for Testing and Materials (ASTM). ASTM D3776M-09A covers the measurement of fabric mass per unit area (weight) and is applicable to most fabrics. ASTM D5034-09, also known as the Grab test, is a standard test method for breaking strength and elongation of textile fabrics. WSP 120.6 and WSP 10.0 (05) are standardized tests created by World Strategic Partners for testing the properties of nonwoven fabrics.
Referring toFIGS. 1A-1D ,3,4-6 and9A-9C, thecleaning pad 100 is configured to scrub afloor surface 10 and absorb fluids on thefloor surface 10. In some examples, thecleaning pad 100 is attached to a cleaning implement such as amobile robot 400 or ahandheld mop 500. The cleaning implement 400, 500 may include asprayer 462, 512 that sprays a cleaningfluid 172 on thefloor surface 10. The implement 400, 500 is used to scrub and remove any smears (e.g., dirt, oil, food, sauces, coffee, coffee grounds) that are being absorbed by thepad 100 along with the appliedfluid 172 that dissovles and/or loosens thesmears 22. Some of the smears may have viscoelastic properties, which exhibit both viscous and elastic characteristic (e.g., honey). Thecleaning pad 100 is absorbent and has anouter surface 105a that includes a randomly appliedabrasive layer 106 comprisingmeltblown fibers 107. As the implement 400, 500 moves about thefloor surface 10, thecleaning pad 100 wipes thefloor surface 10 with theabrasive side 105b containing theabrasive layer 106b of meltblown fibers and absorbs cleaning solution sprayed onto thefloor surface 10 with only a light amount of force than otherwise required by scrubbing mops having a non-abrasive cleaning element.
Referring toFIG. 4, in some implementations, the implement 400 is a compact, lightweight autonomousmobile robot 400 that weighs less than 5lbs and navigates and cleans afloor surface 10. Themobile robot 400 may include abody 410 supported by a drive system (not shown) that can maneuver therobot 400 across thefloor surface 10 based on a drive command having x, y, and θ components, for example. As shown, therobot body 410 has a square shape. However, thebody 410 may have other shapes, including but not limited to a circular shape, an oval shape, a tear drop shape, a rectangular shape, a combination of a square or rectangular front and a circular back, or a longitudinally asymmetrical combination of any of these shapes. Therobot body 410 has aforward portion 412 and arearward portion 414. Thebody 410 also includes a bottom portion (not shown) and atop portion 418. The bottom portion of therobot body 410 further comprises one or more rear cliff sensors (not shown) in one or both of the two rear corners of therobot 400 and one or more forward cliff sensors located in one or both of the front corners of themobile robot 400 for preventing falls from ledged surfaces. In embodiments, the cliff sensors may be mechanical drop sensors or light based proximity sensors, such as an IR (infrared) pair, a dual emitter, single receiver or dual receiver, single emitter IR light based proximity sensor aimed downward at afloor surface 10. In some examples, the one or more forward cliff sensors and one or more rear cliff sensors are placed at an angle relative to the forward and rear corners, respectively, such that they cut the corners, spanning between sidewalls of therobot 400 and covering the corner as closely as possible to detect flooring height changes beyond a threshold accommodated by reversible robot wheel drop prior. Placing the cliff sensors proximate the corners of therobot 400 ensures that they will trigger immediately when therobot 400 overhangs a flooring drop and prevent the robot wheels from advancing over the drop edge.
In some implementations, theforward portion 412 of thebody 410 carries amovable bumper 430 for detecting collisions in longitudinal (A,F) or lateral (L,R) directions. Thebumper 430 has a shape complementing therobot body 410 and extends forward therobot body 410 making the overall dimension of theforward portion 412 wider than therearward portion 414 of the robot body 410 (the robot as shown has a square shape). The bottom portion of therobot body 410 supports thecleaning pad 100. In embodiments, thepad 100 extends beyond the width of thebumper 430 such that therobot 400 can position an outer edge of thepad 100 up to and along a tough to reach surface or into a crevice, such a wall floor interface, and such that the surface or crevice is cleaned by the extended edge of thepad 100 the while therobot 400 moves in a wall following motion. The embodiment of apad 100 extending beyond the width of thebumper 430 enables therobot 400 to clean in cracks and crevices beyond the reach of therobot body 410. In embodiments, such as those shown inFIGS. 1A-1D andFIGS. 8A-8C and9E, thepad 100 has bluntly cut ends 100d such that theairlaid layers 101, 102, 103 are exposed at both ends 100d of thepad 100. Instead of thewrap layer 105 being sealed at theends 100d of thepad 100 and compressing the ends 1.00d of theairlaid layers 101, 102, 103, the full length of thepad 100 is available for fluid absorption and cleaning. No portion of the airlaid core is compressed by thewrap layer 105 and therefore unable to absorbfluid 172. Additionally, a useddisposable pad 100 of this embodiment will not have soaking wet, floppy ends of sealedwrap layer 105 at the completion of a cleaning run. All fluid 172 will be securely absorbed and held by the airlaid core, preventing any drips and preventing a user from undesirably contacting dirty wet ends of thepad 100.
As shown inFIGS. 4 and9A-9G, therobot 400 may drive back and forth to cover a specific portion of thefloor surface 10. As therobot 400 drives back and forth, it cleans the area it is traversing and therefore provides a deep scrub to thefloor surface 10. Areservoir 475 housed by therobot body 410 holds a cleaning fluid 172 (i.e. cleaning solution) and may hold 170-230 mL of fluid. In embodiments, thereservoir 475 holds 200mL of fluid. Therobot 400 may include afluid applicator 462 connected to thereservoir 475 by a tube. Thefluid applicator 462 may be a sprayer having at least one nozzle 464 that distributes fluid over thefloor surface 10. Thefluid applicator 462 may have multiple nozzles 464 each configured to spray the fluid at an angle and distance different than another nozzle 464. In some examples, therobot 400 includes two nozzles 464, vertically stacked in a recess in thefluid applicator 462 and angled and spaced such that onenozzle 464a sprays relatively longer lengths offluid 172a forward and downward to cover an area in front of therobot 400 with a a forward supply of applied fluid 173a and theother nozzle 464b sprays relatively shorter lengths fluid 172b forward and downward to leave a rearward supply of applied fluid 173b on an area in front of but closer to therobot 400 than the area of applied fluid 173a dispensed by thetop nozzle 464a. In embodiments, the nozzle 464 ornozzles 464a, 464b dispensefluid 172, 172a, 172b in an area pattern that extends one robot width W_R and at least one robot length L_R in dimension. In some embodiments, thetop nozzle 464a andbottom nozzle 464b apply fluid 172a, 172b in two distinct spaced apart strips of applied fluid 173a, 173b that do not extend to the full width W_R of therobot 400 such that thepad 100 passes through the outer edges of the strips of applied fluid 173a, 173b in forward and backward angled scrubbing motions as described herein. In embodiments, the strips of applied fluid 173a, 173b cover a width W_S of 75-95% of the robot width W_R and a combined length L_S of 75-95% of the robot length L_R. In some implementations, therobot 400 only sprays on traversed areas of thefloor surface 10.
Moreover, the back and forth movement of therobot 400 breaks down stains on thesurface floor 10. The broken down stains are then absorbed by thecleaning pad 100. In some examples, thecleaning pad 100 picks up enough of the sprayed fluid to avoid uneven streaks if thecleaning pad 100 picks up too much liquid,e.g fluid 172. In case of too little fluid absorption, therobot 400 might leave fluid and wheel traces. In some embodiments, thecleaning pad 100 leaves a residue of the fluid, which could be water or some other cleaning agent including solutions containing cleansing agents, to provide a visible sheen on thesurface floor 10 being scrubbed. In some examples, the fluid contains antibacterial solution, e.g., an alcohol containing solution. A thin layer of residue, therefore, is purposely not absorbed by thecleaning pad 100 to allow the fluid to kill a higher percentage of genus. Therefore, thecleaning pad 100 does not swell or expand and provides a minimal increase in total pad thickness T_T. This characteristic of thecleaning pad 100 prevents therobot 400 from tilting backwards or pitching up if thecleaning pad 100 expands. Thecleaning pad 100 is sufficiently rigid to support the front of the robot. In some examples, thecleaning pad 100 absorbs up to 180 ml or 90% of the total fluid contained in therobot reservoir 475. In some examples, the cleaning pad holds about 55 to about 60 ml of fluid and a fully saturated wrap layer holds about 6 to about 8 ml offluid 172. In some examples the ratio of fluid retention in the airlaid core 101,102,103 to theouter wrap layer 105 is about 9:1 to about 5:1.
Thepad 100 androbot 400 are sized and shaped such that the transfer of fluid from the reservoir to theabsorptive pad 100 maintains the forward and aft balance of the less than5lb robot 400 during dynamic motion. The fluid distribution is designed so that therobot 400 continually propels thepad 100 over afloor surface 10 without the interference of the increasingly saturatedpad 100 and decreasingly occupiedfluid reservoir 475 lifting the back 414 of therobot 400 and pitching thefront 412 of therobot 400 downward and thereby applying movement-prohibitive downward force to therobot 400. Therobot 400 is able to move thepad 100 across thefloor surface 10 even when thepad 100 is fully saturated with fluid. Therobot 400 however includes the feature of tracking the amount offloor surface 10 travelled and/or the amount of fluid remaining in thereservoir 475 and provides an audible and/or visible alert to a user that thepad 100 requires replacement and/or thereservoir 475 requires refilling. In embodiments, therobot 400 stops moving and remains in place on the floor surface if thepad 100 is fully saturated, and there remains floor to be cleaned once thepad 100 is replaced.
FIGS. 9A through 9G detail the spraying, pad wetting, and scrubbing motions of one embodiment of themobile robot 400. In some implementations, therobot 400 only applies fluid 172 to areas of thefloor surface 10 that therobot 100 has already traversed. In one example, thefluid applicator 462 hasmultiple nozzles 464a, 464b each configured to spray thefluid 172a, 172b in a direction different than anothernozzle 464a, 164b. Thefluid applicator 462 may apply fluid 172 downward rather than outward, dripping or sprayingfluid 172 directly in front of therobot 100. In some examples, thefluid applicator 462 is a microfiber cloth or strip, a fluid dispersion brush, or a sprayer.
Referring toFIGS. 9A-9D and9F-9G, in some implementations, therobot 400 may execute a cleaning behavior by moving in a forward direction F toward anobstacle 20, followed by moving in a backward or reverse direction A. As indicated inFIGS. 9A and 9B, therobot 400 may drive in a forward drive direction a first distance Fd to a first location L1. As therobot 400 moves backwards a second distance Ad to a second location L2, thenozzles 464a, 464b simultaneously spray longer lengths fluid 172a and shorter lengths offluid 172b onto thefloor surface 10 in a forward and/or downward direction in front of therobot 400 after therobot 400 has moved at least a distance D across an area of thefloor surface 10 that was already traversed in the forward drive direction F. In one example, the fluid 172 is applied to an area substantially equal to or less than the area footprint AF of therobot 400. Because distance D is the distance spanning at least the length L_R of therobot 400, therobot 400 determines that the area offloor 10 traverses isclear floor surface 10 unoccupied by furniture,walls 20, cliffs, carpets or other surfaces or obstacles onto which cleaningfluid 172 would be applied if therobot 100 had not already verified the presence of aclear floor surface 10 for receivingcleaning fluid 172. By moving in a forward direction F and then backing up prior to applyingcleaning fluid 172, therobot 400 identifies boundaries, such as a flooring changes and walls, and prevents fluid damage to those items.
As shown inFIGS. 4,9B and 9C, in some examples, thefluid applicator 462 is asprayer 462 that includes at least twonozzles 464a, 464b, each distributing the fluid 172 evenly across thefloor surface 10 in two strips of applied fluid 173a, 173b. The twonozzles 464a, 464b are each configured to spray the fluid at an angle and distance different than anothernozzle 464a, 464b. In some examples, the twonozzles 464a, 464b are vertically stacked in a recess in thefluid applicator 462 and angled from horizontal and spaced apart from one another such that onenozzle 464a sprays relatively longer lengths offluid 172a forward and downward to cover an area in front of therobot 400 with a forward supply of applied fluid 173a, and theother nozzle 464b sprays relatively shorter lengths fluid 172b forward and downward to leave a rearward supply of applied fluid 173b on an area in front of but closer to therobot 400 than the area of applied fluid 173a dispensed by thetop nozzle 464a. In embodiments, the nozzle 464 ornozzles 464a, 464b dispensefluid 172, 172a, 172b in an area pattern that extends one robot width W_R and at least one robot length L_R in dimension. In some embodiments, thetop nozzle 464a andbottom nozzle 464b apply fluid 172a, 172b in two distinct spaced apart strips of applied fluid 173a, 173b that do not extend to the full width W_R of therobot 400 such that thepad 100 passes through the outer edges of the strips of applied fluid 173a, 173b in forward and backward angled scrubbing motions as described herein. In embodiments, the strips of applied fluid 173a, 173b cover a width Ws of 75-95% of the robot width W_R and a combined length L_S of 75-95% of the robot length L_R. In embodiments, the strips of applied fluid 173a, 173b may be substantially rectangular shaped or ellipse shaped. In embodiments, thenozzles 464a, 464b complete each spray cycle by sucking in a small volume of fluid at the opening of the nozzle so that no fluid 172 leaks from the nozzle following each instance of spraying.
Referring toFIGS. 9D,9F and9G, in some examples, therobot 400 may drive back and forth to cover a specific portion of thefloor surface 10, wetting thecleaning pad 100 at the start of a cleaning run and/or scrubbing thefloor surface 10. Therobot 400 drives back and forth, cleaning the area traverse and therefore providing a thorough scrub to thefloor surface 10. Therobot 400 oscillates the attachedpad 100 in an orbit of 12-15mm to scrub thefloor 10 and applies approximately 0.4536 kg (1 pound) of downward pushing force or less to the pad.
In some examples, thefluid applicator 462 applies fluid 172 to an area in front of thecleaning pad 100 and in the direction of travel (e.g., forward direction F) of themobile robot 100. In some examples, the fluid 172 is applied to an area thecleaning pad 100 has previously occupied. In some examples, the area thecleaning pad 100 has occupied is recorded on a stored map that is accessible to a robot controller 150, as shown in the diagram ofFIG. 10. Therobot 400 may include acleaning system 1060 for cleaning or treating afloor surface 10.
In some examples, therobot 400 knows where it has been based on storing its coverage locations on a map stored on the non-transitory-memory 1054 of therobot 400 or on an external storage medium accessible by therobot 400 through wired or wireless means during a cleaning run. Therobot 400sensors 5010 may include a camera and/or one or more ranging lasers for building a map of a space. In some examples, therobot controller 1050 uses the map of walls, furniture, flooring changes andother obstacles 10 to position and pose therobot 400 at locations far enough away from obstacles and/or flooring changes prior to the application of cleaningfluid 172. This has the advantage of applyingfluid 172 to areas offloor surface 10 having no known obstacles thereon.
In some examples, therobot 100 moves in a back and forth motion to moisten thecleaning pad 100 and/or scrub thefloor surface 10 to whichfluid 172 has been applied. Therobot 400 may move in a birdsfoot pattern through the footprint area AF on thefloor surface 10 to whichfluid 172 has been applied. As depicted, in some implementations, the birdsfoot cleaning routine involves moving therobot 100 in forward direction F and a backward or reverse direction A along acenter trajectory 1000 and in forward direction F and a backward direction A along left 1010 and right 1005 trajectories. In some examples, theleft trajectory 1010 and theright trajectory 1005 are arcuate trajectories that extend outward in an arc from a starting point along thecenter trajectory 1000. Theleft trajectory 1010 and theright trajectory 1005 may be straight line trajectories that extend outward in a straight line from thecenter trajectory 1000.
FIGS. 9D and9F depict two birdsfoot trajectories. In the example ofFIG. 9D, therobot 400 moves in a forward direction F from Position A along thecenter trajectory 1000 until it encounters awall 20 and triggers asensor 5010, such as a bump sensor, at Position B. Therobot 400 then moves in a backward direction A along the center trajectory to a distance equal to or greater than the distance to be covered by fluid application. For example, therobot 400 moves backward along thecenter trajectory 1000 by at least onerobot length 1 to Position G, which may be the same position as Position A. Therobot 400 applies fluid 172 to an area substantially equal to or less than the footprint area AF of therobot 100 and returns to thewall 20, thecleaning pad 400 passing through the fluid 172 and cleaning thefloor surface 10. From position B, therobot 100 retracts either along aleft trajectory 1010 or aright trajectory 1005 before returning to Position B and covering the remaining trajectory. Each time therobot 400 moves forward and backward along thecenter trajectory 1000, lefttrajectory 1010 andright trajectory 1005, thecleaning pad 100 passes through the appliedfluid 172, scrubbing dirt, debris and other particulate matter from thefloor surface 10 to which thefluid 172 is applied and absorbing the dirty fluid into thecleaning pad 100 and away from thefloor surface 10. The scrubbing motion of the moistened pad combined with the solvent characteristics of the cleaningfluid 172 breaks down and loosens dried stains and dirt. The cleaningfluid 172 applied by therobot 400 suspends loosened debris such that thecleaning pad 100 absorbs the suspended debris and wicks it away from thefloor surface 10.
In the example ofFIG. 9F, therobot 400 similarly moves from a starting position, Position A, through appliedfluid 172, along acenter trajectory 1000 to a wall position, Position B. Therobot 400 backs off of thewall 20 along thecenter trajectory 1000 to Position C, which may be the same position as Position A, before covering left andright trajectories 1010, 1005, extending to positions D and F, with the cleaningfluid 172 distributed along thetrajectories 1010, 1005 by thecleaning pad 100. In one example, each time therobot 400 extends along a trajectory outward from thecenter trajectory 1000, therobot 400 returns to a position along the center trajectory as indicated by Positions A, C, E and G, as depicted inFIG. 9F. In some implementations, therobot 400 may vary the sequence of backward direction A movements and forward direction F movements along one or more distinct trajectories to move thecleaning pad 100 and cleaningfluid 172 in an effective and efficient coverage pattern across the floor surface.
In some examples, therobot 100 may move in a birdsfoot coverage pattern to moisten all portions of thecleaning pad 100 upon starting a cleaning run. As depicted inFIG. 9E, thebottom surface 100b of thecleaning pad 100 has a center area PC and right and left lateral edge areas PR and PL. When therobot 100 starts a cleaning run, or cleaning routine, thecleaning pad 100 is dry and needs to be moistened to reduce friction and also to spread cleaningfluid 172 along thefloor surface 10 to scrub debris therefrom.
Therobot 400 therefore applies fluid at a higher volumetric flow rate initially at the start of a cleaning run such that thecleaning pad 100 is readily moistened. In one implementation, the first volumetric flow rate is set by spraying about 1mL of fluid every 45,72 cm (1.5 feet) initially for a period of time such as l-3minutes, and the second volumetric flow rate is set by spraying every 91,44 cm (3 feet), wherein each spray of fluid is less than 1mL of volume. In embodiments, therobot 400 applies fluid 172 every 30,48 cm or 60,96 cm (one to two feet) at the start of a run to saturate thewrap layer 105 of thepad 100 early in the cleaning run. After a period of time and/or distance, such as a duration of 2-10 minutes, therobot 400 applies fluid at intervals of every 91,44 cm to 152.4 cm (three to five feet) because thepad 100 is moistened and able to scrub thefloor 10. AsFIG. 9G depicts, in some examples, at the start of a cleaning run, therobot 400 drives thecleaning pad 100 through applied fluid 172 such that the center area PC of thebottom surface 100b of thecleaning pad 100 and the left and right lateral edge areas PR and PL of thecleaning pad 100 each pass through the appliedfluid 172 separately, thereby moistening theentire cleaning pad 100 along the entirebottom surface 100b of thecleaning pad 100 in contact with thefloor surface 10.
In the example ofFIG. 9G, therobot 400 moves in a forward direction F and 10 then backward direction A along acenter trajectory 1000, passing the center of thepad 100 through the appliedfluid 172. Therobot 400 then drives in a forward direction F and backward direction A along aright trajectory 1005, passing the left lateral area PL of thecleaning pad 100 through the appliedfluid 172. Therobot 100 then drives in a forward direction F and backward direction A along aleft trajectory 1010, passing the right lateral area PR of thecleaning pad 100 through the appliedfluid 172. At the start of the cleaning run, the robot applies fluid 172 at a relatively high initial volumetric flow rate Vi and/or high initial frequency of application, applying a larger quantity offluid 172 more frequently to thesurface 10 and/or applying a fixed amount offluid 172 more frequently to thesurface 10 to moisten thecleaning pad 100 quickly. Moistening the cleaning pad reduces friction and also enables thepad 100 to dissolvemore debris 22 without requiring more frequent applications offluid 172. In embodiments, the coefficient of friction of thewarp layer 105 of thepad 100 varies from 0.3 to 0.5 depending on material of thefloor 10 and wetness of thepad 100. In one embodiment, adry pad 100 moving on glass has a coefficient of friction of around 0.4 to 0.5, and wet on tiles has a coefficient of friction of about 0.25 to 0.4.
Once thewrap layer 105 of thecleaning pad 100 is moistened, therobot 400 continues its cleaning run and subsequently applies fluid 172 at a second volumetric flow rate Vf. This second volumetric flow rate Vf is relatively lower than the initial flow rate Vi at the start of the cleaning run because thecleaning pad 100 is already moistened and effectively moves cleaning fluid across thesurface 10 as it scrubs. In one implementation, the initial volumetric flow rate Vi is set by spraying about 1mL of fluid every 30.48 cm (1.5 feet) initially for a period of time such as l-3minutes, and the second volumetric flow rate Vf is set by spraying every 91.44 cm (3 feet), wherein each spray of fluid is less than 1mL of volume. Therobot 400 adjusts the volumetric flow rate V such that acleaning pad 100 of specified dimensions is moistened on thebottom surface 100b (FIG. 9E) without being fully wetted to capacity internally in theairlaid layers 101, 102, 103. Thebottom surface 100b of thecleaning pad 100 is initially moistened without the absorbent interior of thepad 100 being water logged such that thecleaning pad 100 remains fully absorbent for the remainder of the cleaning run. The back and forth movement of therobot 400 breaks down stains 22 on thefloor surface 10. The broken downstains 22 are then absorbed by thecleaning pad 100.
In some examples, thecleaning pad 100 picks up enough of the sprayedfluid 172 to avoid uneven streaks. In some examples, thecleaning pad 100 leaves a residue of the solution to provide a visible sheen to thefloor surface 10 being scrubbed. In some examples, the fluid 172 contains antibacterial solution; therefore, a thin layer of residue is purposely not absorbed by thecleaning pad 100 to allow the fluid 172 to kill a higher percentage of germs.
In an embodiment, the pad may be scented. The scent agent may be integrated into or applied onto one or more of the airlaid core layers, the liner or a combination of the airlaid layers and liner. The scenting agent may be inert in a pre- activation stage and activated by fluid to release scent so that the pad only produces a scent during use and otherwise produces no scent while stored. In another embodiment, the pad includes a cleaning agent or surfactant that may be integrated into or applied onto one or more of the airlaid core layers, the liner, or a combination of the airlaid layers and liner. In one embodiment, the cleaning agent is applied to only the back surface (unexposed, non-meltblown side) of the liner in contact with the lower most airlaid core member such that the cleaning agent is released through the porous liner, onto the cleaning surface when in contact with fluid. The cleaning agent may be a foaming agent and/or a cleaning agent with a visibly glossy sheen indicating the application of the cleaning agent the cleaning surface. In another embodiment, the pad includes one or more chemical preservatives applied to or manufactured within the cardboard backing element. The preservatives are selected to prevent the growth
of wood spores that may be present in the wood based backing element. Some embodiments of the pad may include all of these features - conventional scent agent, cleaning agent, antibacterial agent and preservatives - or combinations of fewer than all of these features, including, for example, an encapsulated scent..
Referring toFIG. 5, in some examples, the implement 500 is amop 500. Themop 500 includes abody 502 supporting areservoir 504 that holds a cleaning fluid 172 (e.g. a cleaning solution). Ahandle 506 is disposed on one side of thebody 502. The handle includes acontroller 508 for controlling the release of the fluid from thereservoir 504. A movablerotatable base 510 is disposed on the other end of thebody 502 opposite thehandle 506. Thebase 510 includes afluid applicator 512 connected to thereservoir 504 by a tube (not shown). Thefluid applicator 512 may be a sprayer having at least onenozzle 514 that distributes fluid over thefloor surface 10. Thenozzle 514 sprays forward and downwards of the base 510 towards thefloor surface 10. A user controlling thecontroller 508 sprays the fluid 172 when needed. Thefluid applicator 512 may havemultiple nozzles 514 each configured to spray the fluid in a direction different than anothernozzle 514.
Referring toFIGS. 6, and8E-8G, aretainer 600, 600a, 600b may be disposed on the implement 400, 500 supporting thecleaning pad 100. Theretainer 600, 600a, 600b is disposed on a bottom portion of the implement 400, 500 for retaining thecleaning pad 100. In one embodiment, theretainer 600 may include hook-and-loop fasteners, and in another embodiment, theretainer 600 may include clips, or retention brackets, and selectively moveable clips or retention brackets for selectively releasing the pad for removal. Other types of retainers may be used to connect thecleaning pad 100 to implement 400, 500, such as snaps, clamps, brackets, adhesive, etc., which may be configured to allow the release of thecleaning pad 100 upon activation of a pad release mechanism located on the implement 400, 500 such that user need not touch the dirty used pad to remove the pad from the cleaning implement 400, 500.
FIG. 7 provides an exemplary arrangement of operations for amethod 700 of constructing acleaning pad 100. Themethod 700 includes disposing 710 afirst airlaid layer 101 on asecond airlaid layer 102 and disposing 720 thesecond airlaid layer 102 on a thirdairlaid layer 103. Themethod 700 further includes wrapping 730 awrap layer 104 around the first, second, and thirdairlaid layers 101, 102, 103. Thewrap layer 104 includes aspunlace wrap layer 105, and a meltblown abrasive 107 adhered to thespunlace wrap layer 105.
In some examples, themethod 700 further includes adhering and randomly arranging meltblown abrasive 107 on thespunlace wrap layer 105. Additionally or alternatively, the meltblown abrasive fibers may have a diameter of between about 0.1 µm and about 20 µm. Themethod 700 may further include arranging the meltblown abrasive and thespunlace wrap layer 105 to have a collective thickness of between 0.5 mm and about 0.7 mm on thespunlace wrap layer 105. In some examples, the melblown abrasive 107 creates a thickness gap of 0.5mm between thewrap layer 105 and thefloor 10. Because of this thickness gap, thepad 100 can pick up a 1.5mm diameter bubble of fluid sitting on thefloor 10 with surface tension without requiring force. The lowest points of the embossedcover 105 layer are only 0.5 mm from thefloor 10 and the remainder of the surface area ofwrap layer 105 is 3mm from thefloor 10.
Themethod 700 may further include arranging the meltblown abrasive 107 on thespunlace wrap layer 105 to provide a covered surface ratio between the meltblown abrasive 107 and thespunlace wrap layer 105 of between about 60% and about 70%. In some examples, themethod 700 may include adhering thefirst airlaid layer 101 to thesecond airlaid layer 102 and adhering thesecond airlaid layer 102 to thethird airlaid layer 103. The airlaid layers 101, 102, 103 may be of a cellulose based textile material (e.g., a material including fluff pulp).
In some implementations, themethod 700 may include where the first, second, and thirdairlaid layers 101, 102, 103, thespunlace wrap layer 105, and the meltblown abrasive are configured to increase in thickness by less than 30% after fluid absorption. Themethod 700 may further include embossing the spunlace layer105. Themethod 700 may also include disposing sodium polyacrylate in one or more of theairlaid layers 101, 102, 103.
In some examples, themethod 700 further includes configuring theairlaid layers 101, 102, 103 and wraplayer 104 to have a combined width of between about 80 millimeters and about 68 millimeters, and a combined length of between about 200 millimeters and about 212 millimeters. Themethod 700 may further include configuring theairlaid layers 101, 102, 103 and thewrap layer 104 to have a combined thickness of between about 6.5 millimeters and about 8.5 millimeters. Themethod 700 may include configuring theairlaid layers 101, 102, 103 to have a combined airlaid width of between 69 millimeters and about 75 millimeters, and a combined airlaid length of between about 165 millimeters and about 171 millimeters.
FIGS.8E-G demonstrate an exemplary release mechanism for thepad 100 as described herein.FIGS. 8A-8C show an embodiment of thepad 100 having a core of threeairlaid layers 101, 102, 103 bonded and enclosed in awrap layer 105 adhered to the top surface of thetop airlaid layer 101. Additionally, the embodiment ofFIGS. 8A-8C include acardboard backing layer 85 adhered to the top surface of thepad 100. Thecardboard backing layer 85 protrudes beyond the longitudinal edges of thepad 100 and the protrudinglongitudinal edges 86 of thecardboard backing layer 85 attach to thepad holder 82 of therobot 100. In one embodiment, thecardboard backing layer 85 is between 0.02" and 0.03" thick, between 68 and 72 mm wide and between 90-94mm long. In one embodiment, thecardboard backing layer 85 is .026" thick, 70mm wide and 92mm long. In one embodiment, thecardboard backing layer 85 is coated on both sides with a water resistant coating, such as wax or polymer or a combination of water resistant materials, such as wax/polyvinyl alcohol, polyamine, and thecardboard backing layer 85 does not disintegrate when wetted.
In embodiments, thebottom surface 100b of thepad 100 may include one or morehair catching strips 100c for catch and collect loose hair during cleaning. In the embodiment ofFIG. 9E, twohair catching strips 100c are depicted in dashed line to indicate the option nature of this feature. In an embodiment having one or morehair catching strips 100c, the strip orstrips 100c may be located on outer longitudinal edges of thepad 100 or in a single strip on either longitudinal edge of the pad or down the middle of the pad. In embodiments, eachhair catching strip 100c is less than 30% of the total surface area of thebottom surface 100b of thepad 100 and preferably is less than 20% of the surface area of thebottom surface 100b of thepad 100. Thehair catching strip 100c may be a strip of material added to thewrap layer 105 that includes loose fibers with catching features, such as Velcro^® hooks, rough edged fibers or fibers with a fused tip.
As shown inFIGS.8E and8G, thepad 100 as described herein can be secured to an autonomous robot through apad holder 82 which can be attached to therobot 400. An exemplarypad release mechanism 83 is also shown in an up or pad-secure position. Thepad release mechanism 83 includes aretainer 600a, or lip, that holds thepad 100 securely in place by grasping the protrudinglongitudinal edges 86 of thecardboard backing layer 85. In the version shown, the tip or end 84 of thepad release mechanism 83 includes amoveable retention clip 600a and aneject protrusion 84 that slides up through a slot or opening in thepad holder 82 when the pad is inserted into theholder 82, and is pushed into a down position to release thesecured pad 100 as shown inFIG 8G, as shown here pushing down on the attachedbacking layer 85, e.g. cardboard backing. The relationship between the pad and thepad holder 82 is also shown in a top view inFIG 8F. In one embodiment, thepad release mechanism 83 is activated by atoggle button 477 located under thehandle 419 of therobot 400, as shown inFIG. 4. The toggle motion is indicated by the dotteddouble arrow 478. Toggling thetoggle button 477 moves a spring actuator that rotates thepad release mechanism 83, moving theretention clip 600a away from thecardboard backing layer 85 and moving theeject protrusion 84 through the slot in the the pad holder 882 so that the eject protrusion pushes thepad 100 out of the holder.
Returning toFIGS. 8A and 8B, in embodiments, thecardboard backing layer 85 may includecutouts 88 centered along the protrudinglongitudinal edges 86 of thecardboard backing layer 85 and corresponding in position with raisedprotrusion 94 on the bottom of thepad holder 82, as shown inFIG. 8D. In another embodiment, thecardboard backing layer 85 contains a first set ofcutouts 88 centered on the protrudinglongitudinal edges 86 of thecardboard backing layer 85 and a second set ofcutouts 90 on the lateral edges of thecardboard backing layer 85. Thecutouts 88, 90 are symmetrically centered along the longitudinal center axis PCA_lon of thepad 100 and lateral center axis PCA_lat of thepad 100 and engage with correspondingprotrusions 92, 94 centered on the longitudinal center axis HCA_lon of the underside of thepad holder 82 and lateral center axis PCA_lat on the underside of thepad holder 82. Thepad holder 82 of the embodiment ofFIG. 8D includes three raisedprotrusions 92, 94. This is so that a user may install thepad 100 in either of two identical directions (180 degrees opposite to one another) while allowing thepad holder 82 to more easily release thepad 100 when therelease mechanism 83 is triggered. Other embodiments of the pad holder include fourprotrusions 92, 94 corresponding in position to the fourcutouts 88, 90 on the cardboard backing layer inFIG. 8C. In still other embodiments, thepad holder 82 andpad 100 respectively include raised protrusions and corresponding cut outs in any other number or configuration for holding the pad in place and enabling selective release.
InFIG. 8D, the raisedprotrusion 94 on the longitudinal edge of thepad holder 82 is obscured by the retainingbracket 600a, which is shown in phantom view so that the raisedprotrusion 94 therebeneath is visible in the exemplary view. Theprotrusions 92, 94 both poke yoke attachment of thedisposable pad 100 to the bottom of thepad holder 82 so that alignment if thepad 100 to theholder 82 is precise and retain thepad 100 relatively stationary to thepad holder 82 by preventing lateral and/or transverse slippage.
Because thecutouts 88, 90 extend into the surface area of thecardboard backing layer 85, they respectively interface with more lateral and longitudinal surface area of the raisedprotrusions 92, 94 and the pad is held in place against rotational forces as well by the cutout-protrusion retention system. Therobot 100 moves in a scrubbing motion, as described above, and, in embodiments, thepad holder 82 oscillates the pad for additional scrubbing. In embodiments, therobot 400 oscillates the attachedpad 100 in an orbit of 12-15mm to scrub thefloor 10 and applies approximately 0.4536 kg (1 pound) of downward pushing force or less to the pad. By aligningcutouts 88, 90 in thecardboard backing layer 85 withprotrusions 92, 94, thepad 100 remains stationary relative to the holder during use, and the application of scrubbing motion, including oscillation motion, directly transfers from thepad holder 82 through the layers of the pad without loss of transferred movement.
In embodiments, the pad ofFIGS. 1A-1D and8A-8C are disposable pads. In other embodiments, thepad 100 is a reusable microfiber cloth pad having the same absorptive characteristics as those described herein with regard to embodiments. In embodiments having a washable, reusable microfiber cloth, the top surface of the cloth includes a secured stiff backing layer shaped and positioned like the cardboard backing layer of the embodiments ofFIGS. 8A-8C. The stiff backing layer is made of heat resistant, washable material that can be machine dried without melting or degrading the backing. The stiff backing layer is dimensioned and has cutouts as described herein for interchangeable use with the embodiment of thepad holder 82 described with regard to the embodiments ofFIGS. 8A-8G.
In other examples, thepad 100 is intended for use as a disposable dry cloth and comprises a single layer of needle punched spunbond or spunlace material having exposed fibers for entrapping hair. Thedry pad 100 embodiment further comprises a chemical treatment that adds a tackiness characteristic to thepad 100 for retaining dirt and debris. In one embodiment, the chemical treatment is a material such as that marketed under the trade name DRAKESOL.

Claims

A mobile floor cleaning robot (400) comprising:
a robot body (410) defining a forward drive direction (F);
a drive supporting the robot body to maneuver the robot across a surface, the drive comprising right and left drive wheels disposed on corresponding right and
left portions of the robot body; and
a cleaning assembly disposed on the robot body (410), the cleaning assembly comprising:
a pad holder (82) disposed forward of the drive wheels and configured to receive a cleaning pad (100);
a reservoir (475; 504) to hold a volume of fluid (172); and
a fluid applicator (462) in fluid communication with the reservoir, the fluid applicator configured to apply the fluid (172) along the forward drive direction (F) forward of the pad holder (82);
characterized in that the robot is configured to apply fluid (172) to a floor surface (10) at an initial volumetric flow rate to moisten the cleaning pad (100), the initial volumetric flow rate being relatively higher than a subsequent volumetric flow rate when the cleaning pad (100) is moistened.
The robot of claim 1, wherein the pad holder (82) has a top portion and a bottom portion, the bottom portion having a bottom surface arranged within between about 0.5 cm and about 1.5 cm of the bottom surface and configured to receive the cleaning pad (100), the bottom surface of the pad holder comprising at least 40% of a surface area of a footprint (AF) of the robot, and the bottom portion having raised protrusions (92, 94) extending therefrom; and an orbital oscillator having less than 1 cm of orbital range disposed on the top portion of the pad holder (82);
wherein the pad holder is configured to permit more than 80 percent of the orbital range of the orbital oscillator to be transmitted from the top of the received cleaning pad to the bottom surface of the received cleaning pad and wherein the pad holder has a release mechanism (83) configured to eject the cleaning pad from the bottom surface of the pad holder upon actuation of the release mechanism.
The robot of claim 1 or 2, wherein the fluid applicator is a sprayer (462).
The robot of any of the preceding claims 1 to 3, wherein the robot is configured to move in a birdsfoot coverage pattern to moisten the cleaning pad upon starting a cleaning run.
The robot of claims 1 or 2, wherein the cleaning pad is configured to absorb about 90% of the fluid volume held in the reservoir.
The robot of claims 1 or 2, further comprising a backing layer (85) on the cleaning pad for engaging with the pad holder.
The robot of claim 6, wherein at least one raised protrusion on the bottom of the pad holder is positioned for aligning to and engaging with a shaped slot cut out of the backing layer.
The robot of claims 1 or 2, wherein the overall weight of the robot without retaining any fluid is between about 1 kg and about 1.5 kg and with retaining fluid is between about 1.5 kg to 4.5 kg.
The robot of claims 1 or 2, wherein applying fluid to the floor surface at the initial volumetric flow rate includes spraying with sprays of a predetermined volume and applying fluid to the floor surface at the subsequent volumetric flow rate includes sprays of fluid of a lesser volume.
The robot of claims 1 or 2, wherein applying fluid to the floor surface at the initial volumetric flow rate includes spraying with sprays with a predetermined spacing and applying fluid to the floor surface at the subsequent volumetric flow rate includes sprays of fluid with a larger spacing.
The robot of claims 1 or 2, wherein the initial volumetric flow rate is set by spraying 1 mL of fluid every 30cm for a period of about 1 to 3 minutes, and the subsequent volumetric flow rate is set by spraying every 91,44 cm (3 feet), wherein each spray of fluid is less than 1 mL of volume.
A method of cleaning a surface with mobile floor cleaning robot (400) including a surface cleaning pad (100), including:
applying a surface cleaning liquid (172) to the surface to be cleaned and passing the surface cleaning pad (100) over the surface,
characterized in that the cleaning liquid (172) is applied fluid to a floor surface (10) at an initial volumetric flow rate to moisten the cleaning pad, the initial volumetric flow rate being relatively higher than a subsequent volumetric flow rate when the cleaning pad is moistened.
The method of claim 12, wherein applying the cleaning liquid includes spaying the cleaning liquid on the surface.