US20100236013A1 - Vacuum Cleaner Sensor - Google Patents

Abstract

A vacuum cleaner having an inlet nozzle for conveying air and dust to a dirt separator chamber via a dirty air inlet passage is provided. The dirt separator chamber has a chamber opening, an emitter window, and a receiver window. The emitter window and the receiver window may be substantially transparent. An emitter is positioned so that it emits light or another electromagnetic energy into the separator chamber via the emitter window. A receiver is positioned so that it receives light or another electromagnetic energy from the separator chamber via the receiver window. The emitter window and the receiver window each form a projection into the separator chamber during operation of the vacuum cleaner. Airflow creates a cyclone in the dirt separator chamber, and the projections increase the air velocity over the projections, cleaning the emitter window and the receiver window of dust.

Description

FIELD OF THE INVENTION
• The present invention relates to features for use with vacuum cleaners that employ a cyclonic cleaning system, such as upright vacuum cleaners, commercial vacuums, stick vacuums, canister vacuums, central vacuums, and the like.
BACKGROUND OF THE INVENTION
• Vacuum cleaning devices, such as upright and canister vacuum cleaners, stick vacuums, electric brooms and other devices, are in widespread use as tools to clean floors, upholstery, stairs, and other surfaces. Known vacuum cleaning devices have various features intended to improve their utility or cleaning effectiveness. For example, pressure sensors in a vacuum cleaner may detect when the bag is full of dust or indicate when the user should replace the bag or filters, or empty the dust cup. The pressure sensor device alerts the user to replace the bag or dust cup, and makes it less necessary to check the bag manually. Using a cyclone separator vacuum, windows to view the cyclone separator may be useful to determine the level of dust in the cyclone separator. However, dirt may be spun against the walls of the cyclone separator, obscuring the view from the windows.
• While the prior art provides various features relating to cleaning effectiveness and user convenience, there still exists a need for improvement of and alternative designs for these and other features of vacuum cleaning devices.
SUMMARY OF THE INVENTION
• In a first exemplary aspect, there is provided a vacuum cleaner that has an inlet nozzle for conveying air and dust to a dirt separator chamber via a dirty air inlet passage. The dirt separator chamber has a chamber opening, an emitter window, and a receiver window. The emitter window and the receiver window may be substantially transparent. An emitter is positioned so that it emits light or other electromagnetic energy into the separator chamber via the emitter window. A receiver is positioned so that it receives light or other electromagnetic energy from the separator chamber via the receiver window. One or both of the emitter window and the receiver window forms a projection into the separator chamber during operation of the vacuum cleaner.
• In another exemplary aspect, there is provided a vacuum cleaner that has an inlet nozzle for conveying air and dust to a dirt separator chamber via a dirty air inlet passage. The dirt separator chamber has a chamber opening, an emitter window, and a receiver window. One or both of the emitter window and the receiver window forms a projection into the separator chamber. Air flows into the dirt separator chamber from the inlet nozzle and the dirty air inlet passage, and the air is formed into a cyclone either inside the dirt separator chamber, or before the air gets to the dirt separator chamber. The velocity of the air in the cyclone increases as the air passes over the projections of the emitter window and the receiver window. The velocity over the projections may be increased by at least about 10%, and more preferably by at least about 40%. In exemplary aspects, the velocity may increase from about 10 meters per second to at least about 11 meters per second, and more preferably to at least about 14 meters per second.
• The recitation of this summary of the invention is not intended to limit the claimed invention. Other aspects, embodiments, modifications to and features of the claimed invention will be apparent to persons of ordinary skill in view of the disclosures herein. Furthermore, this recitation of the summary of the invention, and the other disclosures provided herein, are not intended to diminish the scope of the claims in this or any prior or subsequent related or unrelated application.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present invention is described in detail with reference to the examples of embodiments shown in the following figures in which like parts are designated by like reference numerals.
• FIG. 1 is a schematic cross sectional view of an exemplary embodiment of a vacuum cleaner having a dirt cup releasably positioned within a housing, where the dirt cup has internal, self-cleaning projections to facilitate the operation of an emitter and a receiver located outside the dirt cup.
• FIG. 2 is a partial schematic perspective view along plane T ofFIG. 1.
• FIG. 3 is a partial schematic cross sectional view of along plane T ofFIG. 1.
• FIG. 4 is a partial schematic cross sectional diagram view along plane T ofFIG. 1.
• FIG. 5 is a cross-sectional view of the separator chamber ofFIG. 1, with arrows designating exemplary airflow therein.
• FIG. 6 is an isometric view of an alternative embodiment of a separator chamber of the present invention.
• FIG. 7 is a cross sectional view of another embodiment of a window of the present invention, showing a membrane window in a “resting” position.
• FIG. 8 is a cross section view of another embodiment of a window of the present invention, showing a membrane window in an “active” position.
• FIG. 9 is another embodiment showing an emitter and a receiver on the same side of a window.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTIONS
• The present disclosure provides numerous inventive features for vacuum cleaners. A number of these features and alternative embodiments of the invention are described with reference to their exemplary use in an upright vacuum cleaner, such as the vacuum cleaner shown in partial view inFIG. 1. It will be appreciated, however, that the features described herein can be used in various other contexts. For example, the various features described herein can be used with canister vacuums, stick vacuums, portable and handheld vacuums, shop vacuums, central vacuum systems, and so on. Furthermore, the various features described herein may be used separately from one another or in any suitable combination. The present disclosure illustrating the use of the various inventions described herein is not intended to limit the inventions in any way. Moreover, not all of the parts of a typical vacuum cleaner (such as the vacuum fan and motor, inlet nozzles, filters, etc.) are shown, but they will be readily understood by persons of ordinary skill in the art. Only parts relevant to demonstrate the operation of the various inventions described herein are shown.
• Referring toFIG. 1, a typicalvacuum cleaner housing105 includes a motor (not shown) and a dirt separator assembly (shown cut away). Thehousing105 may be formed from a plastic or metal material, and may also include other components. For example, thehousing105 may include one or more wheels (not shown) mounted to the outer surface of thehousing105 to allow thehousing105 to roll. The motor and the dirt separator assembly may be attached to thevacuum cleaner housing105. In an alternate embodiment, the motor and dirt separator assembly may be attached to one or more structures separate from thehousing105, but may be in communication with thehousing105 through hoses, as known in the art. Examples of vacuum cleaners having various housing configurations and with which the present invention may be used are provided in the attached U.S. Pat. Nos. 6,502,277; 5,935,279; 7,163,568; 5,813,085; 6,829,804; and 6,910,245, which references are incorporated into the present disclosure. The illustrated exemplary embodiment is used in a device similar to the two-stage cleaners shown in U.S. Pat. Nos. 5,935,279 and 6,910,245, but it may be adapted for use in single-stage cleaners or other kinds of cleaning device.
• Thedirt separator assembly100 may be removably attached to thehousing105, and mounted by tabs, hooks, latches or other well-known devices. Thedirt separator assembly100 may include aninlet102 that receives dirt and air from a dirty air inlet on the vacuum cleaner (not shown), and anoutlet104 that conveys air substantially removed of the dirt to a vacuum fan associated with the motor (not shown). The dirty air inlet (not shown) is associated with, for example and without limitation, a floor or inlet nozzle or an above-floor cleaning hose. Suction created by the motor creates a vacuum that draws air and dirt through the floor nozzle or the above-floor cleaning hose. The combined air and dirt enter thedirt separator assembly100, where the dirt is substantially removed from the air. The dirt may be removed by the air by, for example, the creation and maintenance of a cyclone inside thedirt separator assembly100, which may force the dirt out of the cyclone and into thedirt separator assembly100. A filter of screen (not shown) may also be used to remove dirt from the air. When thedirt separator assembly100 is attached to thehousing105, the dirty air inlet of thedirt separator assembly100 may be associated with the floor nozzle or the above-floor cleaning hose, and the outlet may be associated to the vacuum fan and the motor. In other embodiments, the motor may be located between the inlet and the dirt separator assembly, in which case it will force air through the dirt separator assembly under positive pressure, as opposed to operating under negative pressure as in the embodiment described above.
• The motor (not shown) may be contained within thehousing105, and may include a vacuum fan. The motor may be any type of device to operate the vacuum fan as known in the art, and may include, for example and without limitation, an electric motor. The motor may operate the vacuum fan to create a suction. The motor may be, for example, an electric motor that is in electrical communication with one or more power supplies. The one or more power supplies may draw electricity from, for example and without limitation, one or more power outlets. In another embodiment, the one or more power supplies may be in communication with one or more batteries. The batteries may provide electricity to the power supply, or may provide electricity to the motor directly. Both one or more power supplies and one or more batteries may be present, and may provide electricity to the motor alternately or in parallel. The one or more power supplies and/or the one or more batteries may be contained within thehousing105, or may provide electricity to the elements contained in thehousing105 via a cable or other electricity transfer device.
• Theseparator chamber110 includes anemitter window120 and areceiver window130. Theseparator chamber110 may be substantially cylindrical, or may be another shape to promote air to form a cyclone or another substantially circular or helical motion. Theseparator chamber110 may be formed from the same material as theemitter window120 and thereceiver window130, or theseparator chamber110 may be formed from a different material from theemitter window120 and/orreceiver window130. For example, theseparator chamber110 may be formed from an opaque material, and thereceiver window130 and theemitter window120 may be formed from a optically translucent material. Theseparator chamber110 is removably attached to thehousing105, and is attached to thehousing105 so that anemitter127 is capable of transmitting electromagnetic energy into theseparator chamber110 via theemitter window120, and areceiver137 is capable of receiving electromagnetic energy from theseparator chamber110 via thereceiver window130. Theemitter window120 and thereceiver window130 are shaped such that they are discontinuous from the inner surface of theseparator chamber110, and form projections within the inner wall of theseparator chamber110. In other embodiments, however, theemitter window120 or thereceiver window130 may simply comprise a portion of theseparator chamber110 wall. Theemitter window120 and/or thereceiver window130 may also be provided as projections that extend the length of theseparator chamber110. An example of such an embodiment is shown inFIG. 6, in which aseparator chamber610 is provided having anemitter window620 and areceiver window630 formed as full-length shapes. In the embodiment ofFIG. 6, the use of such full-length shapes may facilitate manufacture of theseparator chamber610. Also in this embodiment, the emitter and receiver can be placed at any desired location along the emitter andreceiver windows620,630, and multiple sets of emitters and receivers may be used to provide readings at various locations.
• Theemitter window120 may be formed from the same material as theseparator chamber110 wall, or may be formed from a different material and attached to theseparator chamber110 wall in a manner known in the art. Theemitter window120 may comprise an inneremitter window surface121 and an outer emitter window surface. Theemitter window120 is formed from a material that allows some or substantially all of the electromagnetic energy transmitted by theemitter127 to enter theseparator chamber110.
• The inneremitter window surface121 is shaped so that the inneremitter window surface121 projects into theseparator chamber110. The inneremitter window surface121 projection may form a curve that extends into theseparator chamber110. The faces123aand123bof the inneremitter window surface121 that face the axial line of theseparator chamber110 may be flat, or substantially normal to theseparator chamber110 surface, or thefaces123aand123bof the emitter window surface that face the axial line of theseparator chamber110 may be angled or curved. The outer emitter window surface may be flush or continuous with theseparator chamber110 wall's outer surface, or may be discontinuous with theseparator chamber110 wall's outer surface.
• Thereceiver window130 may be formed from the same material as theseparator chamber110 wall, or may be formed from a different material and bonded with theseparator chamber110 wall in a manner known in the art. Thereceiver window130 may comprise an innerreceiver window surface131 and an outer receiver window surface. Thereceiver window130 is formed from a material that allows some or substantially all of the electromagnetic energy transmitted by theemitter127 and entering theseparator chamber110 through theemitter window120 to pass through thereceiver window130 and be received by thereceiver137. The innerreceiver window surface131 may be substantially similar to the inneremitter window surface121, including with respect to thefaces123aand123bof the inneremitter window surface121 and thefaces133aand133bof the innerreceiver window surface131. The outer emitter window surface and the outer receiver window surface also may be substantially similar. Of course, in other embodiments, the inner and outer receiver window surfaces may be shaped differently than the inner and outer emitter window surfaces.
• As noted above, it will be appreciated that theemitter window120 andreceiver window130 can be made in any suitable way. For example, they may be molded integrally with theseparator chamber110 wall. As another example, theseparator chamber110 may be constructed with openings into which the emitter andreceiver windows120,130 are installed. As still another example, theseparator chamber110 wall may be constructed as a continuous wall (as typically done in the prior art), and theemitter window120 andreceiver window130 may be formed by attaching additional material to the inner surface of theseparator chamber110 wall to form projections therein.
• Turning now toFIGS. 2,3, and4, various exemplary views of the vacuum cleaner shown inFIG. 1 are shown along plane T. Theemitter127 andreceiver137 preferably are mounted to thehousing105 and remain with the housing even when theseparator chamber110 is removed for emptying, but this is not required in all embodiments. Theemitter127 may be retained in anemitter housing125, which may be formed from the same material as thehousing105, and may be formed, for example, when thehousing105 is formed. Theemitter housing125 includes one or more attachment points for theemitter127. For example, theemitter housing125 may include one or more projections to which theemitter127 and associated circuitry may be attached by screws or rivets or the like. The construction of emitters and the attachment of the same to vacuum cleaner housings are known in the art, and the details need not be described herein. Theemitter housing125 is positioned within thehousing105 so that theemitter127 aligns with theemitter window120 on theseparator chamber110 when theseparator chamber110 is mounted to the housing.
• Theemitter127 may be any electronic apparatus capable of transmitting electromagnetic energy. For example, theemitter127 may emit visible light, or may emit infrared or ultraviolet light. Theemitter window120 of theseparator chamber110 is capable of transmitting the electromagnetic energy of theemitter127 into theseparator chamber110. For example, if theemitter127 emits visible light, then theemitter window120 may be capable of transmitting some or all of the visible light emitted from theemitter127 into theseparator chamber110. Theemitter127 is positioned so that theemitter127 transmits the electromagnetic energy in the general direction of theemitter window120. If desired, theemitter window120 may be shaped to help direct the electromagnetic energy towards thereceiver window130. It will also be appreciated that theemitter window120 may be shaped as a lens to focus or spread the energy. Theemitter127 may be in electrical communication with a power supply (not shown), as known in the art, and may be operated continuously or periodically by any suitable control circuitry.
• Thereceiver137 may be mounted to thehousing105 in areceiver housing135, which may be formed from the same material as thehousing105, and may be formed, for example, when thehousing105 is formed. Thereceiver housing135 includes one or more attachment points for thereceiver137. For example, thereceiver housing135 may include one or more projections to which thereceiver137 and associated circuitry may be attached by screws or rivets or the like, as known in the art. Thereceiver housing135 is positioned within thehousing105 so that thereceiver137 aligns with thereceiver window130 when theseparator chamber110 is mounted to thehousing105.
• Thereceiver137 may comprise any electronic apparatus capable of receiving and detecting electromagnetic energy. For example, thereceiver137 may receive and detect visible light, or may detect infrared or ultraviolet light. Thereceiver137 is capable of detecting the electromagnetic energy from the emitter127 (at least when there is nothing obstructing the energy path), so that if theemitter127 emits, for example, visible light, thereceiver137 is capable of detecting the visible light. Thereceiver137 is positioned so that thereceiver137 may receive the electromagnetic energy from the general direction of thereceiver window130, and thereceiver window130 may be shaped to help direct the energy from theemitter window120 to thereceiver137. It will also be appreciated that thereceiver window130 may be shaped as a lens to focus or spread the energy. Thereceiver137 may be in electrical communication with a power supply (not shown), as known in the art, and may be operated continuously or periodically by any suitable control circuitry.
• Together, theemitter127 andreceiver137 are operated to evaluate the amount of dirt or dust in theseparator chamber110. For example, theemitter127 may be energized to emit electromagnetic energy, and thereceiver137 may be used to determine how much of the energy is received. The signal from thereceiver137 may vary depending on the amount of energy received. The amount of signal loss may be measured to determine the amount and nature of the dirt in theseparator chamber127. For example, if no signal is received, then the chamber may be obstructed with dirt at the level of theemitter127 andreceiver137, indicating that it should be emptied. More than oneemitter127 and more than onereceiver137 may be used in an embodiment. For example, a number ofemitters127 and a number ofreceivers137 may be arranged so that different levels of dirt in theseparator chamber127 may be detected. In other embodiments, theemitter127 and/orreceiver137 may comprise a cluster of multiple emitter elements and/or receiver elements at generally one location. Additionally, more than oneemitter window120 and more than onereceiver window130 may be formed with theseparator chamber110 wall. As another example, the signal may be detected to include rapid, large fluctuations, indicating that relatively large particles are passing through the cyclone. As another example, the signal may be fluctuating with a relatively small amplitude, indicating that smaller particles are passing through the cyclone.
• Theemitter127 and thereceiver137 may be continuously energized while the vacuum is in operation, and the signal generated by thereceiver137 may be continuously monitored by the control logic. In another embodiment, theemitter127 andreceiver137 may be energized at the start of the operation of the vacuum, or at the end of the operation of the vacuum, or may be selectively energized and the signal monitored at discrete intervals. In yet another embodiment, the control logic may presume that theseparator chamber110 is obstructed by dust and/or debris at the start up of the vacuum, and may energize a light to indicate that the separator chamber is obstructed. If, after the signal from thereceiver137 is evaluated, the control logic determines that theseparator chamber110 is not sufficiently obstructed, the control logic may de-energize the light to indicate that theseparator chamber110 is not obstructed. The control logic may then continue to monitor the signal from thereceiver137, or may not monitor the signal from thereceiver137 until the vacuum is restarted.
• Of course, theemitter127 andreceiver137 may be calibrated to account for actual or expected losses of energy through a clean orempty separator chamber110. In such a case, the calibration may be performed at the factory (e.g., by including a simple loss factor into the control logic), or it may be performed in use by using the signal loss after each cleaning as a baseline loss for that cleaning session (e.g., by resetting the sensor baseline loss level each time theseparator chamber110 is emptied or providing a manual reset button). Theemitter127 andreceiver137 may be calibrated so that if an actual or expected loss of energy through a clean orempty separator chamber110 is not found (i.e., the energy received by thereceiver127 is higher than what would be expected if the energy passed through a clean or empty separator chamber110), it may be recognized that theseparator chamber110 is not seated or is seated improperly. In a situation where theseparator chamber110 is not seated or is seated improperly, the control logic may not allow the motor (not shown) to start, or may stop the motor if it is running. The control logic may also energize an error light or similar indicator to note that theseparator chamber110 is not seated properly or is missing. Theemitter127,receiver137 also may be oriented and arranged such that they rely on theirwindows120,130 to direct the emitted energy from theemitter127 to thereceiver137. In such an embodiment, thereceiver137 does not receive any appreciable amount of energy from theemitter127 unless thedirt separator assembly100 is properly installed in thehousing105. This embodiment can be used to indicate a fault condition when thedirt separator assembly100 is not properly installed.
• The foregoing and/or other control methods may be used, as known in the art, to provide the user with an indication of the type and/or amount of dirt that is passing through theseparator chamber110 or other functions, such as to indicate that the separator chamber is missing.
• When the vacuum cleaner is switched on, the motor (not shown) creates a vacuum. Air and dirt are drawn into the vacuum cleaner via theinlet102. Theinlet102 directs the air and dirt into theseparator chamber110, where the chamber walls, shape of the inlet, and the pressure difference between the inlet and the outlet create one or more cyclones or other substantially circular or helical airflow patterns. As known in the art, one or more filters or screens may be located within thechamber110 to help create a cyclone and/or filter the air leaving theseparator chamber110. The vacuum may comprise a single cyclone, or, as in the shown embodiment, may comprise a multiple stage cyclone separator system. In the shown embodiment, theseparator chamber110 in which the emitter and receiver operates is thefirst stage140 of a two-stage cyclone. A filter (not shown) may be located in theseparator chamber110, and the windows and sensors may be located below the filter, or at the level of the filter but oriented so that the filter does not obstruct the operation of the sensors. Air leaving thefirst stage140 passes into asecond stage cyclone150, which deposits removed particles into an associatedchamber152.
• Within theseparator chamber110, the air rotates generally tangentially with respect to theseparator chamber110 walls, as known in the art. While embodiments described herein are referred to as “cyclones,” it will be understood that embodiments may be used with any kind of centrifugal separator, or even with devices that do not use centrifugal or cyclone flow. This rotation applies a radial centrifugal force that pushes the dust from the inside of theseparator chamber110 to the wall of theseparator chamber110. As the dust and larger particles are separated, they tend to settle in alower portion142 of theseparator chamber110. One problem discovered with cyclone separator chambers is that dirt and dust tends to cling to the wall of theseparator chamber110 both during and after operation of the vacuum cleaner. Such clinging dirt may interfere with the operation of thetransmitter127 andreceiver137 by reducing the strength of the signal reaching thereceiver137.
• Turning now toFIG. 5, there is shown an exemplary cross-sectional view of theseparator chamber110, with arrows designating the airflow along the boundary layer adjacent the inner wall of theseparator chamber110. The inner surface of the wall includes anexemplary projection510, which may be the inneremitter window surface121 or the innerreceiver window surface131. Only one of the window surfaces is shown as an example in this figure, but a similar analysis and results are obtained with multiple projecting window surfaces. As shown, the air flows around theseparator chamber110, and is directed away from the outer wall as it passes over theprojection510. As the air passes over theprojection510, its velocity increases, for reasons that are explained according to the well-known principles of fluid dynamics. The boundary layer of the cyclonic air in theseparator chamber110 also may decrease as the air passes over theprojection510. Without being bound by any theory of operation, it is believed that the increased air flow velocity, as well as the decreased boundary layer size, at theprojection510 help dislodge dust particles from theprojection510 surface. This provides a cleaning action, generally not present throughout the remainder of theseparator chamber110 wall, that helps keep theprojection510 free of accumulated dust and operating properly. It is believed that the velocity of the airflow passing over a projection510 (such as the one shown or over similar projections formed as emitter and/or receiver windows) can be increased by 10%, 40%, 50%, or more. For example, it has been calculated that the airflow velocity may increase from about 5 to 10 meters per second without projections being present, to about 11 meters per second, about 14 meters per second, or about 15 meters per second at locations where aprojection510 is provided. In one simulation, it was calculated that adding projections increased the airflow over the projections to about 150% of the value at locations where no projections were present, and decreased the boundary layer (i.e., the portion of the airflow between the wall surface and the location at which peak velocity is obtained) to about 80% of the value at locations where no projections were provided.
• The airflow inFIG. 5 indicates a clockwise cyclone rotation, but a counterclockwise rotation may be used instead. Furthermore, theprojection510 may be optimized for a particular rotation direction (i.e., clockwise or counterclockwise). Theprojection510 also may be oriented along a helical path to account for vertical movement of the airflow. If desired, features may be provided to help make the air flow over the projections in a regular pattern. For example flow control planes may be provided along the upper and lower walls of each projection. Other variations will be apparent to persons of ordinary skill in the art in view of the present disclosure.
• One particular advantage of some embodiments of the invention (which advantage is not required in all embodiments, of course) is that theseparator chamber110 may be removed from thehousing105 for cleaning, maintenance, and/or replacement without removing theemitter127 orreceiver137. Theemitter window120 and thereceiver window130, being attached to theseparator chamber110, are also removed with theseparator chamber110 for cleaning. A user may clean the inner surface of theseparator chamber110, including theinner receiver window130 and theinner emitter window120, to remove accumulated dust that is not removed by the increased air velocity and decreased boundary layer, and thereby restore the device to its most favorable operating conditions. To this end, forming the emitter andreceiver windows120,130 with projections has the added advantage of providing visual and tactile indicators to help direct the user to areas requiring attention during cleaning. While such cleaning may be desirable, it may not be required, and it is expected that typical users will not specifically clean thewindows120,130 during regular cleaning. Once cleaned, the user may then replace theseparator chamber110 within thehousing105. When the user replaces theseparator chamber110 within thehousing105, theemitter window120 is positioned within thehousing105 so that theemitter127 is operable to transmit electromagnetic energy into theseparator chamber110. Thereceiver137 is also positioned to receive electromagnetic energy from theseparator chamber110, transmitted through thereceiver window130. Thus, not only does this exemplary embodiment provide a self-cleaning function during use, but it also allows the user to clean the emitter andreceiver windows120,130 in a way that may not be possible if the windows remained in thehousing105 or if theemitter127 andreceiver137 were not separable from theseparator chamber110. Despite the foregoing, in alternative embodiments, theemitter127 and/orreceiver137 may be attached to thehousing105, which may not be removable from the housing, or may be removed by disconnecting electrical circuits to theemitter127 and/orreceiver137.
• In other embodiments of the invention, theemitter window120 and/or thereceiver window130 may be formed from an elastic material. The use of a deformable window for theemitter window120 and/orreceiver window130 may thus allow the window to be cleaned of dust and debris at the beginning and/or end of the operation of the vacuum. Either thereceiver window130 or theemitter window120 may be formed from an elastic material, or both thereceiver window130 and theemitter window120 may be formed from an elastic material. If thereceiver window130 or theemitter window120 is formed from an elastic material, then the other may be formed as a projection into theseparator chamber110, shown above, or may be formed in another way.
• An example of a deformable window is show shown inFIG. 7. Here, anelastic emitter window710 is shown with anemitter127. The elastic material allows electromagnetic energy from theemitter127 to enter theseparator chamber110. For example, the elastic material may be substantially optically transparent, or may be transparent to the electromagnetic energy that theemitter127 emits. The elastic material is molded in a “resting” position, such as shown inFIG. 7, but is deformable into at least one “active” position, such as shown inFIG. 8, in which the geometry of the window is different from the geometry in the “resting” position. In the shown embodiment, thewindow127 assumes a generally parabolic shape extending outside theseparator chamber110 in the resting position, and generally the opposite shape in the active position. In other embodiments, however, other shapes may be used.
• Thewindow710 may be formed of the same material as theseparator chamber110 and joined to theseparator chamber110 by adhesives, welding or the like. Thewindow710 also may be formed integrally with theseparator chamber110 as, for example, a relatively thin portion of the chamber wall. Thewindow710 alternatively may be formed of a different material as theseparator chamber110, and attached by any of the various known attachment means, such as ultrasonic welding, adhesives, fasteners, and the like. InFIG. 7 andFIG. 8, for example, theelastic emitter window710 is formed of a separate, relatively thin piece of flexible material that is sandwiched between theseparator chamber110 wall and another piece ofmaterial720 attached to theseparator chamber110. Theelastic emitter window710 may be attached on the outside of theseparator chamber110 wall or the inside of theseparator chamber110 wall. Theelastic window710 also may be formed from more than one layer of material. For example, the elastic material may be formed from one or more plastic layers (or one or more metal layers or other reflective layers, in the case of a flexible mirror as described below). In the shown embodiments, thewindow710 comprises a generally continuous piece of material, but in other embodiments, thewindow710 may comprise a rigid or relatively rigid central portion that is mounted in a flexible ring.
• In a preferred embodiment, thewindow710 is adapted to deform from the resting position to the active position, then back to the resting position, many times. A suitable material is believed to be polyethylene terephthalate, which relatively strong, impact resistant and transparent. The rate at which the material transitions from the resting position to the active position, and vice versa, may be gradual or relatively quick. Preferably, the transition rate is relatively quick to help remove debris by rapidly accelerating and/or decelerating thewindow710.
• As shown inFIG. 8, when the vacuum cleaner is in operation, the air pressure inside theseparator chamber110 drops below the air pressure outside theseparator chamber110. This pressure difference causes theelastic emitter window710 to flex or deform into theseparator chamber110, placing theelastic emitter window710 in the active position. Deformation of theelastic emitter window710 into theseparator chamber110 may dislodge dirt or other debris adhering to theemitter window710, and thereby clean theelastic emitter window710 of some or all debris. If theemitter window710 is configured to flex relatively quickly to the active position when the vacuum is activated, this may assist with dislodging any clinging debris. In addition, when theelastic emitter window710 is in the active position, it forms a projection into theseparator chamber110, and the airflow around the projection may also clean dust and debris from theelastic emitter window710 as explained above with respect to previous embodiments. Theelastic emitter window710 may remain in the active position while the air pressure inside theseparator chamber110 is less than the air pressure outside theseparator chamber110.
• When the vacuum is not in operation, the pressure inside and outside theseparator chamber110 reaches an equilibrium, and theelastic emitter window710 returns to the resting position, shown inFIG. 7. Dust or other debris that accumulates over theelastic emitter window710 during operation may be dislodged when theelastic emitter window710 returns to the resting position. In addition, theemitter window710 may be retracted from theseparator chamber110 so that it does not obstruct the path of dirt when theseparator chamber110 is being emptied.
• While the foregoing embodiments describe thewindow710 being displaced by the vacuum generated inside theseparator chamber110, such movement may be assisted or controlled by other means. For example, springs may be used to bias thewindow710 into either position, and a mechanical device may be used to force thewindow710 into either position. As one example of such an arrangement, a mechanism may be used to push theemitter127 against thewindow710 to move them both into theseparator chamber110 when the vacuum fan is operating.
• Of course,FIG. 7 andFIG. 8 may also represent the receiver window and thereceiver137, so that the receiver window may be formed from an elastic material, and may operate in a similar way as theelastic emitter window710 shown inFIG. 7 andFIG. 8. In addition, theelastic emitter window710 and/or thereceiver window130 may extend along the length of theseparator chamber110, as in, for example,FIG. 6.
• Another exemplary embodiment of the invention is shown inFIG. 9. In embodiments such as this, theemitter127 and thereceiver137 may be positioned on the same side of asingle window910. Areflector920 is provided to reflect the signal from theemitter127 to thereceiver137. Thereflector920 may be formed from or coated with a material that reflects some or all of the electromagnetic energy emitted by theemitter127. For example, thereflector920 may be coated or formed from a mirrored material (such as a thin foil) that reflects visible or infrared light, if theemitter127 emits visible or infrared light. Theemitter127 may emit electromagnetic energy through theemitter window910 and into theseparator chamber110. Some or all of the electromagnetic energy may be reflected by thereceiver window920 back into theseparator chamber110. Thereceiver137 may then receive the electromagnetic energy through the emitter window910 (or, alternatively, through a separate window provided for the receiver137), and may transmit a signal to suitable control circuitry to operate the vacuum as described in the preceding paragraphs. Theemitter window910 and/or thereceiver window920 may be fixed, as shown inFIGS. 1-6, or may be elastic, as shown inFIGS. 7-9 (FIG. 9 shows thewindow910 andreflector920 in the resting position). Thereflector920 also may be located outside theseparator chamber110 behind a suitable rigid offlexible receiver window920. For example, thereflector920 may be located on thehousing105.
• It will be appreciated that embodiments of the devices disclosed herein may be used in any vacuum cleaner having a rigid dirt receptacle. For example, U.S. Pat. Nos. 6,613,129, 6,994,740 and 5,935,279 and U.S. application Ser. No. 11/761,961 disclose upright vacuum cleaners having one or more cyclonic cleaning stages. The cyclones include a dirt receptacle formed by a rigid housing that surrounds or sits below the cyclone member. Embodiments of the present invention may be used in any of the various cyclone stages (e.g., in an upstream coarse particle separator or a downstream fine particle separator), or in a dirt receptacle located below the cyclone itself (in which dirt typically continues to circulate in a swirling manner). Embodiments of the present disclosure also may be used in horizontal or tilted cyclones, such as the cyclone shown in U.S. Pat. No. 6,502,277, in central vacuums using cyclone separators, or in other kinds or configurations of vacuum cleaner. All of the foregoing references are incorporated herein and form part of the present disclosure.
• The present disclosure describes a number of new, useful and nonobvious features and/or combinations of features that may be used alone, together, with upright vacuum cleaners, canister vacuum cleaners or other types of cleaning device, or in other ways. The embodiments described herein are all exemplary, and are not intended to limit the scope of the inventions in any way. It will be appreciated that the inventions described herein can be modified and adapted in various ways and for different uses, and all such modifications and adaptations are included in the scope of this disclosure and the appended claims.

Claims (24)

1. A sensor assembly for a vacuum cleaner, the sensor assembly comprising:

a vacuum cleaner housing;

a dirt separator chamber having a dirty air inlet, a clean air outlet, an emitter window, and a receiver window;

an emitter mounted on the housing and positioned to emit electromagnetic energy through the emitter window; and

a receiver mounted on the housing and positioned to receive electromagnetic energy through the receiver window;

wherein the dirt separator chamber is removable from the housing, and at least one of the emitter window and the receiver window forms a projection into the dirt separator chamber during operation of the vacuum cleaner.

2. The vacuum cleaner ofclaim 1, wherein the emitter window and the receiver window form respective projections into the dirt separator chamber during operation of the vacuum cleaner.

3. The vacuum cleaner ofclaim 2, further comprising an emitter housing attached to the vacuum cleaner housing, the emitter being attached to the emitter housing.

4. The vacuum cleaner ofclaim 2, further comprising a receiver housing attached to the vacuum cleaner housing, the receiver being attached to the receiver housing.

5. The vacuum cleaner ofclaim 1, wherein the dirt separator chamber comprises a cyclone separator.

6. The vacuum cleaner ofclaim 1, wherein a fan is adapted to convey dirty air into the dirt separator chamber under positive pressure.

7. The vacuum cleaner ofclaim 1, wherein a fan is adapted to convey dirty air into the dirt separator chamber under negative pressure.

8. The vacuum cleaner ofclaim 1, wherein the projection comprises a raised surface that is discontinuous from the curvature of the separator chamber.

9. The vacuum cleaner ofclaim 1, wherein the projection comprises a lens.

10. The vacuum cleaner ofclaim 1, wherein the dirt separator chamber is removable from the vacuum cleaner housing without removing the emitter and the receiver.

11. A sensor assembly for a vacuum cleaner, the sensor assembly comprising:

a vacuum cleaner housing;

a dirt separator chamber having a dirty air inlet, a clean air outlet, an emitter window, and a receiver window, the dirt separator chamber being adapted to contain a generally cyclonic air flow;

an emitter mounted on the housing and positioned to emit electromagnetic energy through the emitter window; and

a receiver mounted on the housing and positioned to receive electromagnetic energy through the receiver window;

wherein at least one of the emitter window and the receiver window forms a projection into the dirt separator chamber during operation of the vacuum cleaner, and wherein the velocity of the generally cyclonic air flow increases by at least about10% at a location adjacent the projection.

12. The vacuum cleaner ofclaim 11, wherein the emitter window and the receiver window form respective projections into the dirt separator chamber during operation of the vacuum cleaner.

13. The vacuum cleaner ofclaim 11, wherein the velocity of the generally cyclonic air flow increases by at least about 40% at a location adjacent the projection.

14. The vacuum cleaner ofclaim 11, wherein the velocity of the generally cyclonic air flow increases by at least about 50% at a location adjacent the projection.

15. The vacuum cleaner ofclaim 11, wherein the velocity of the generally cyclonic air flow increases from about 10 meters per second to about 11 meters per second at a location adjacent the projection.

16. The vacuum cleaner ofclaim 11, wherein the velocity of the generally cyclonic air flow increases from about 10 meters per second to about 14 meters per second at a location adjacent the projection.

17. The vacuum cleaner ofclaim 11, wherein the velocity of the generally cyclonic air flow increases from about 10 meters per second to about 15 meters per second at a location adjacent the projection.

18. The vacuum cleaner ofclaim 11, wherein the boundary layer of the generally cyclonic air flow decreases by about 20% at a location adjacent the projection.

19. The vacuum cleaner ofclaim 11, wherein the dirt separator chamber is removable from the vacuum cleaner housing without removing the emitter and the receiver.

20. A sensor assembly for a vacuum cleaner, the sensor assembly comprising:

a vacuum cleaner housing;

a dirt separator chamber having a dirty air inlet, a clean air outlet, an emitter window, and a receiver window, the dirt separator chamber being adapted to contain a generally cyclonic air flow;

an emitter mounted on the housing and positioned to emit electromagnetic energy through the emitter window; and

a receiver mounted on the housing and positioned to receive electromagnetic energy through the receiver window;

wherein at least one of the emitter window and the receiver window forms a projection into the dirt separator chamber during operation of the vacuum cleaner, and wherein the boundary layer of the generally cyclonic air flow decreases by about 20% at a location adjacent the projection.

21. The vacuum cleaner ofclaim 20, wherein the emitter window and the receiver window form respective projections into the dirt separator chamber.

22. The vacuum cleaner ofclaim 21, wherein the emitter window and the receiver window are rigidly formed with the dirt separator chamber.

23. The vacuum cleaner ofclaim 21, wherein the emitter window and the receiver window are movable with respect to the dirt separator chamber.

24. The vacuum cleaner ofclaim 20, wherein the dirt separator chamber is removable from the vacuum cleaner housing without removing the emitter and the receiver.

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