VACUUM CLEANER HEAD
This invention relates to a vacuum cleaner head and more particularly but not solely to a vacuum cleaner head for cleaning hard floors.
Vacuum cleaners always comprise some form of head which can engage the floor to pick up dirt and dust. In a so-called upright cleaner, the head is pivoted to an upright body which generally contains means for separating and collecting the dirt and dust that is drawn into the cleaner by the induced airflow. In a so-called canister cleaner, the head is provided at the end of a tubular wand that is connected to a body of the cleaner via an elongate flexible duct. The body of the cleaner contains means for separating and collecting the dirt and dust that is drawn into the cleaner by a motor and fan unit disposed in the body. Sometimes the head of the canister cleaner may be detachable, so that the user can fit other kinds of cleaning tools to the wand.
Floors formed of wood, tiles, stone and other hard materials are now becoming commonplace. Hence, there is a need to provide a head which can both clean the surface of the floor and remove dirt and dust from any crevices in the floor, such as crevices between floorboards. Conventionally, heads for cleaning hard floors comprise an underside having a transverse elongate suction mouth and front and rear rows of static bristles disposed parallel to the suction mouth on opposite sides thereof. Dirt particles are removed from the surface being treated by the suction airflow, with the bristles serving to loosen particles from the surface. Such heads are ineffective in removing dirt which tends to adhere to the surface, and also dirt lodged in crevices in the surface being cleaned. Effective removal of dust from crevices can be achieved by providing a good seal between the nozzle and the floor, thereby promoting airflow through the crevices, whereby dust is removed as the head passes over the crevices. A good seal can be achieved by elongate elastomeric wiper blades or densely packed strips of bristles. However, a disadvantage of this for hard-floor cleaning is that the surface dirt is unable to pass through or beneath the seals and into the suction mouth. In order to overcome this problem, castellated wiper blades or brush strips can be used, but with sealing members of this type, a high airflow rate of 35 litres a second is needed to overcome the reduction in sealing and thereby achieve satisfactory crevice cleaning performance. The high power consumption of fan motors required for such high airflow rates runs contrary to modern energy efficiency requirements. We have now devised a vacuum cleaner head which is particularly suited to cleaning the surfaces of hard floors and also to removing dirt from flat surfaces and surfaces with crevices.
In accordance with the present invention, as seen from a first aspect, there is provided a vacuum cleaner head having a suction mouth on the underside thereof, the suction mouth being substantially surrounded by a seal, wherein a portion of the seal comprises a roller arranged to engage a floor surface being cleaned and to rotate about an axis which extends parallel to the floor surface, the roller comprising a plurality of axially-extending sealing blades disposed around its circumference.
In use, an effective seal between the nozzle and the floor is provided by the seal, so that airflow through the crevices is promoted and effective removal of dust from crevices is achieved. When the head is moved in a direction perpendicular to the longitudinal axis of the roller, any surface dirt and dust in front of the roller simply passes under the roller and is then drawn into the head by the suction airflow.
Preferably the leading and trailing edges of the head are respectively defined by front and rear portions of the head when the head is moved in a forwards direction, said roller preferably being disposed in the front portion and oriented such that its axis of rotation extends perpendicular to the direction of forwards movement.
Preferably the seal comprises a further roller disposed in the rear portion and orientated such that its axis of rotation extends perpendicular to the direction of rearwards movement, said suction mouth being disposed between the rollers.
Preferably the seal comprises opposite end portions which extend downwardly from the underside of the head and lie perpendicular to the axis of the roller.
Preferably the or each roller is arranged to rotate by contact of the roller with the surface being cleaned, although it will be envisaged that the roller may be driven by a motor. Preferably the roller comprises a wheel arranged to engage the surface being cleaned. Preferably the roller comprises a pair of wheels at opposite ends thereof.
The sealing blades may extend parallel to the rotational axis of the roller, or they may extend helically.
Preferably the suction mouth is at least partially surrounded by an inner seal, the inner seal being disposed inwardly of the outer seal on the underside of the head. In use, the inner seal provides a very good seal around the suction mouth so that effective cleaning of crevices is achieved.
Preferably a suction opening is disposed between the inner and outer seals, so that surface dust that has passed under the roller is drawn into the suction airflow through the opening and independently of the aforementioned suction mouth, which primarily acts to provide a crevice cleaning function.
Preferably, means are provided to allow air into the space between the inner and outer seals, so as carry the surface dust towards the suction opening. Preferably, said means is arranged to cause an airflow which extends longitudinally from opposite ends of the roller. In use, the surface dust is drawn into the space between the roller blades. Since the roller blades are rotating, the space in which dust is located is then presented to the suction opening, whereupon the dust is drawn into the opening.
Preferably the suction opening has a height which is equal to or less than the width of the space between adjacent blades at their radially outermost ends.
Preferably, said means to allow air into the space between the inner and outer seals comprises gaps at the ends of the blades adjacent the wheels. Alternatively, the wheels may comprise a portion of reduced diameter which creates an opening that allows air to flow axially along the blades.
In order to prevent the suction opening causing a drop in pressure in the suction mouth, valve means are preferably provided for closing the suction opening: preferably the valve means is formed by the blades of the roller, which rotate and serve to close the suction opening as the cleaner is moved across the floor surface. Preferably the suction mouth is elongate and extends transversely of the head and parallel to said roller. Preferably the head comprises a suction outlet which carries the dirt and dust to a separation device, the suction mouth comprising a pair of suction inlets disposed at respective ends thereof which communicate said suction mouth with said suction outlet, and a baffle disposed intermediate said inlets to direct the flow of air from a central region of the suction mouth through said suction inlets. In this manner airflow is concentrated at the ends of the suction mouth.
Preferably each end of the suction mouth is connected to a respective passageway which allows air to flow into the suction mouth from a point disposed away from the floor surface: this so-called bleed airflow creates turbulence at the ends of the suction mouth which extends down into any crevice and acts to draw in dust particles that are disposed outwardly of the head, thereby providing a cleaning effect which is wider than the actual head.
Preferably each passageway extends downwardly into the suction mouth from an upper surface of the head.
Preferably said suction opening is disposed intermediate opposite ends of the roller.
Preferably said suction opening is fluidly connected to said suction outlet.
Also in accordance with the present invention, as seen from a second aspect, there is provided a vacuum cleaner head having a suction mouth on the underside thereof, the suction mouth being elongate and extending transversely of the head, wherein each end of the suction mouth is connected to a respective passageway arranged to allow air to flow into the suction mouth from a point disposed away from the floor surface.
Preferably each passageway extends downwardly into the suction mouth from an upper surface of the head. Preferably the head comprises a suction outlet which carries the dirt and dust to a separation device, the suction mouth comprising a pair of suction inlets disposed at respective ends thereof which communicate said suction mouth with said suction outlet, and a baffle disposed intermediate said inlets to direct the flow of air from a central region of the suction mouth through said suction inlets.
Preferably the suction mouth is bounded on respective opposite sides thereof by a pair of depending seals which extend longitudinally of the mouth. Preferably the suction mouth is bounded on respective opposite ends thereof by a pair of depending seals which extend transversely of the mouth. Preferably each passageway opens into the suction mouth adjacent the seals disposed at respective opposite ends of the mouth. Preferably the seals are resiliently flexible.
Also in accordance with the present invention, as seen from a third aspect, there is provided a vacuum cleaner head having a suction outlet arranged to carry the dirt and dust to a separation device, an elongate suction mouth extending transversely of the underside of the head, the suction mouth comprising a pair of suction inlets disposed at respective ends thereof which communicate said suction mouth with said suction outlet, and baffle means disposed intermediate said inlets and arranged to direct the flow of air from a central region of the suction mouth through said suction inlets.
The width of each suction inlet preferably increases along the length of the suction mouth towards its respective end.
Preferably the suction inlets extend over 50 - 70% of the area of the suction mouth and most preferably 60%.
Also in accordance with the present invention, as seen from a fourth aspect, there is provided a vacuum cleaner head having a suction outlet arranged to carry the dirt and dust to a separation device, an elongate suction mouth extending transversely of the underside of the head, the suction mouth being bounded on front and rear longitudinal sides thereof by respective depending seals, a suction opening being provided in front of the front seal, the suction opening being fluidly connected to said suction outlet. Preferably the suction inlet is substantially bounded by a seal which comprises said depending seals.
Preferably valve means are provided for periodically closing the suction opening. Preferably the valve means are formed by the blades of a roller, which rotate and serve to close the suction opening as the cleaner is moved across the floor surface, the roller being arranged to engage a floor surface being cleaned and to rotate about an axis which extends parallel to the floor surface, the roller comprising a plurality of axially-extending sealing blades disposed around its circumference.
Preferably the roller extends longitudinally of a c-shaped channel.
Preferably the suction opening is formed in a wall of said channel. Preferably the suction opening has a width which is less than the circumferential spacing between the tips of adjacent blades of the roller.
Preferably said suction opening is disposed intermediate opposite ends of the roller.
Features which are stated as preferred features of any particular aspect of the invention are not limited to that aspect and may be preferred features of any other aspect.
Embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of an embodiment of a cleaning head in accordance with the present invention for a vacuum cleaner;
Figure 2 is a bottom view of the head of Figure 1 ; Figure 3 is a sectional view along the line Ill-Ill of Figure 2;
Figure 4 is a sectional view along the line IV-IV of Figure 2; Figure 5 is a perspective view of an end of the head of Figure 1 , with some parts being shown in outline; and
Figure 6 is a bottom view of an alternative embodiment of cleaning head in accordance with the present invention.
Referring to Figures 1 to 5 of the drawings, there is shown a cleaning head 10 in accordance with the present invention for fitting to a canister vacuum cleaner, the rear of the head 10 comprising a rearwardly-extending tubular suction outlet 1 1 for releasably coupling to the distal end of a tubular wand of the cleaner. In use, a motor and fan unit in the body of the cleaner draws air through the head 10 via the wand.
The head 10 comprises a body 12 of plastics material, which is supported at its rear by a pair of wheels 13. The body 10 comprises a front wall 14, a rear wall 15, opposite end walls 16, a top wall 17 and a bottom wall 18, which define a hollow internal cavity 19. The tubular suction outlet 1 1 is fluidly connected to the cavity 19.
The underside of the body 10 comprises front and rear elongate rollers 20, 21 which extend parallel to each other and transversely of the head 10. An elongate suction mouth 22 also extends transversely of the head 10 and is disposed between the rollers 20, 21 on the underside of the body 12.
The suction mouth 22 is bounded along its front and rear sides by respective elongate seals 23, 24 which depend from the bottom wall 18 of the body 12. The seals 23, 24 are formed of an elastomeric material.
A suction inlet 25 is formed in the bottom wall 18 at each end of the suction mouth 22, the suction inlets 25 serving to fluidly couple the suction mouth 22 with the tubular suction outlet 1 1 via the internal cavity 19 of the head 10. The width of the suction inlets 25 increase gradually towards the outer ends of the suction mouth 22, at which point they extend across the full width of the suction mouth 22. The roof of the suction mouth 22 is open apart from a central region which is closed by a portion of the bottom wall 18 of the body 12. This portion of the bottom wall 18 acts as a baffle 29 to effectively restrict the size of the inlets 25 and confines the inlets 25 to the ends of the suction mouth 22.
A pair of passageways 26a, 26b extend upwardly from each end of the suction mouth 22 along the internal face of the respective end wall 16 of the body 12. The upper end of the passageways 26a, 26b have openings in the top wall 17 of the body 12. The rollers 20, 21 are rotationally mounted at their respective opposite ends to respective end walls 16 of the body 12. A seal 30 depends from each end wall 16. Each roller 20, 21 comprises a plurality of longitudinally-extending sealing blades 27, which are equally spaced around the circumference of the roller and extend radially. The blades 27 are formed of a resiliently flexible elastomeric material. Each roller 20, 21 comprises a wheel 28 at its opposite ends, the wheels 28 having a central portion of a diameter which is slightly greater than the diameter of the blade portion of the rollers and opposite side portions having diameters slightly less than the diameter of the blade portion of the rollers. The rollers 20,21 respectively extend along front and rear c-shaped channels that are partly formed by front and rear wall portions 14,15 respectively, together with a portion of the bottom wall 18 of the body 12. Each of the channels is fluidly connected to the tubular suction outlet 1 1 by respective suction openings 31 , which extend through the bottom wall 18 of the body 18 into the internal cavity 19 of the head 10. The suction openings 31 have a height which is less than the width of the space between adjacent roller blades 27 at their radially outermost ends. The suction openings 31 are disposed between the suction inlets 25 intermediate opposite sides of the head 10.
In use, when the head 10 is placed on a hard floor and suction is applied to the suction outlet 1 1 , air is drawn via the suction openings 31 into the head 10: the incoming air flows around the wheels 28 due to their reduced side cross-sectional profile and due to the fact that air can leak between the ends of the blades 27 and the sides of the wheels 28. The air then flows axially along the inwardly-facing channels between the blades 27 from opposite ends of the roller. As the head 10 is pushed forwardly, the rollers 20,21 are caused to rotate by contact of the wheels 28 with the floor surface. Any dirt on the floor in front of the head 10 passes under the front roller 20 whereupon it is drawn axially off the floor by the aforementioned axial airflow in the lowermost inward roller channel 32. Since the roller 20 is rotating, the roller channel 32 in which the dirt is disposed soon becomes aligned with the front suction opening 31 , whereupon it is drawn into the cavity 19 and onwards towards the body of the cleaner.
Likewise, as the head is moved rearwardly, any dirt on the floor behind the head 10 passes under the rear roller 21 whereupon it is drawn axially to the centre of the roller 20 by the aforementioned axial airflow. Since the roller 21 is rotating, the roller channel in which the dirt is disposed soon become aligned with the rear suction opening 31 , whereupon it is drawn into the cavity 19 and onwards towards the body of the cleaner.
The seals 23,24,30 surrounding the suction mouth 22 prevent any significant airflow through the inlets 25 when the head is on a totally flat hard surface. However, when the head 10 passes over a crevice, air is drawn through the crevice into the suction mouth 22 together with any accumulated dust. The passageways 26a, 26b allows air to flow into the suction mouth 22 from above the head 10 and this so-called bleed airflow creates turbulence at the ends of the suction mouth 22 which extends down into the crevice and acts to draw in dust particles that are disposed laterally of the head, thereby providing a cleaning effect which is wider than the actual head.
The rotating wiper blades 27 partially obstruct or impede the free flow of air through the suction openings 31. If there were no rotating rollers 20,21 to partially obstruct the suction openings 31 they would leak too much suction. If there were no rotating rollers 20,21 to reduce the amount of leakage, the suction openings 31 would have to be so small that they would be rendered useless. The rotating rollers 20,21 create a partial obstruction to the free flow of air through the suction openings 31 , and allows the suction openings 31 to be made larger allowing debris to pass through them while limiting the amount of suction lost needed for good dust removal via the suction inlets 25.
Referring to Figure 6 of the drawings, there is shown an alternative embodiment of cleaning head in accordance with the present invention, which is similar to the cleaning head 10 of Figures 1 to 5 and like parts are given like reference numerals. In this embodiment, the blades 41 of the front and rear rollers 42,43 extend helically (i.e. radially and axially) as opposed to just extending axially. The helical configuration helps to quickly draw surface dirt towards the suction opening 31. A vacuum cleaning head in accordance with the present invention is able to achieve very efficient cleaning of both hard surfaces and crevices without the need for a motor above the range of 700W. When such motors are used with the present invention, airflow rates are in the range of 18-22 litre per second.