Floor tool for vacuum cleaner

Abstract

A floor tool for a vacuum cleaning machine comprises a housing having an upper portion, a front portion, two opposed side portions, and a rear portion, wherein an underside of the tool comprises a flo

Description

The present invention concerns the field of floor treatment machines and relates in particular to vacuum cleaners, or cleaners which include floor suction devices. The present invention relates to a floor tool which is attached to or integrated in a vacuum cleaner in order to clean carpets, rugs, and hard flooring etc. In a typical arrangement the floor tool is attached to a hollow wand that is in fluid communication with a suction turbine by means of a flexible hose. The suction turbine may be disposed within a remote canister or an upright vacuum cleaner fed by the flexible hose. The suction turbine draws air into the canister or upright cleaner for collection of entrained detritus and subsequent disposal. Typically vacuum cleaner floor tools have a base portion provided with an air channel or vacuum slot defined by a recess along the transverse width of the floor tool. The recess opens onto the floor and has an upper aperture which feeds into the wand, so that air and entrained dust may be drawn up into the recess thence to the wand via the aperture. The recess may accommodate a horizontal rotating brush bar which may be motor driven so as to agitate the underlying floor surface. The base portion or underside of the floor tool supports the floor tool on a given surface to be cleaned. The floor tool may be adapted to slide over a floor or carpet surface or may be provided with support wheels to facilitate travel over a floor surface, whilst maintaining the base portion at an optimum cleaning height or disposition. The floor tool may be rendered steerable by means of a first wand pivot which permits up-down movement through an arc, and side-to side pivoting via rotation of the wand with respect to the floor tool, so that twisting of the wand upper portion distal from the floor tool moves the tool left or right so as to follow a respective left or right arc. In use, the floor tool moves over the carpet, rug or hard floor with air being drawn into the vacuum slot via the gap between the front underside of the floor tool base portion. This restricted path accelerates the air as it is drawn into the slot / channel, thereby to entraining dust, debris etc present in the carpet or on the floor. A problem with these floor tools is that the base portion may be sucked down onto the floor or carpet by the Bernoulli effect as air is drawn into the space (or inlet gap) between the floor and the underside of the base portion. This inhibits free travel of the floor tool over the surface to be cleaned. The higher the suction the more effort is required to push or pull the floor tool over the surface. Typically, a higher suction is required when travelling over thick piled floor surfaces such as carpets and rugs. To date this problem has been addressed by providing a bleed aperture in the wand, so as to reduce the suction clamping effect on the floor tool. Bleed apertures must be customised for different vacuum cleaner specifications, for example different power ratings. Furthermore, bleed apertures do not operate at the cleaning plane and therefore do not contribute to cleaning performance. Therefore, the provision of a bleed valve is undesirable. Alternatively, a height adjustment mechanism in the support wheels (or brush bar) may be used to stop the base portion from travelling down too far onto the floor or carpet surface. This requires the incorporation of complex height adjustment measures which act when cleaning different carpet types. This can also reduce the ability of the drawn-in air to entrain detritus for collection. Too low a setting can cause the floor tool to have reduced mobility on thick pile carpets. Too high a setting can make cleaning ineffective. A second problem with a typical floor tool with a narrow inlet gap is that large debris tends to be pushed by the floor tool causing a ‘ploughing effect’ in which large debris is not collected but cast aside. This may be overcome by raising the floor tool to increase clearance between the leading edge of the floor tool and the floor surface, thus allowing the large debris to enter the suction chamber. However, as mentioned above, raising the floor tool tend to reduce the suction, thus reducing cleaning effectiveness. The present invention in its various aspects seeks to address these problems and potentially improve cleaning performance in vacuum cleaners equipped with floor tools of the type described in the foregoing. According to one aspect of the present invention there is provided a floor tool for a vacuum cleaning machine, the floor tool comprising a housing having an upper portion, a front portion, two opposed side portions, and a rear portion, wherein an underside of the tool comprises a floor-facing base portion, the base portion being provided with a transversely extending upwardly recessed channel, wherein the channel is provided with an exit aperture which feeds into a suction conduit for communicating with suction generating means in the vacuum cleaning machine, the arrangement being such that, in use, fluid with entrained detritus is drawn from the tool underside into the recessed channel and out of the exit aperture, wherein a leading edge of the floor tool front portion is defined by a movable visor which is selectively moveable between a first position in which a lower region of the visor defines a first fluid gap between the floor and the visor, and a second position in which the lower region of the visor defines a second fluid gap between the floor and the visor. The present invention may provide the advantage that the visor may be operated between the first position and the second position to alter the airflow characteristics into the floor tool through the first and second fluid gap respectively. This has the effect of reducing the suction clamping effect. This has the added benefit of allowing the operator to selectively increase the size of the fluid gap such that large debris may enter the floor tool, thus allowing for collection of large debris items. By visor it is meant a member which is moveable between at least two positions so as to vary an air inlet gap, in a similar manner to a helmet wind visor. It is not intended to mean that the visor is itself necessarily transparent, although that could of course be an option. The visor is preferably provided upstream of an inlet aperture for allowing airflow into the recessed channel. A sealing element is preferably provided between the visor and the floor tool housing. This may allow for an air-tight seal between the visor and the housing to prevent air leakage. The visor is preferably raised from the first position to the second position, that is to say the first position is preferably a lowered position, and the second position is an elevated position. The visor may be slidingly movable or rotationally movable between the first position and the second position. The visor is preferably rotationally movable between the first position and the second position. Preferably, the visor has a profile which provides a camming surface configured so when the visor is in the lowered position the fluid gap is uniform across the leading edge of the tool. Preferably, the gap across the leading edge is tightened in the lowered position as compared to when the visor is in the elevated position. The first fluid gap is preferably smaller than the second fluid gap. The floor tool may further comprise a latching mechanism for latching the visor in either the first or second position. The latching mechanism may generally resist movement of the visor from the first position to the second position or vice versa. The latching mechanism may be arranged to hold the visor in either the first position or the second position. The visor preferably comprises a lower front plate provided with at least one cut-out portion. The cut-out portion may be substantially trapezoidal in plan. The floor tool may preferably comprise at least two spaced apart cut-out portions. The at least two cutout portions are preferably the same size and shape. More preferably the cut-out portions are provided symmetrically about a centreline of the floor tool, where the centreline is equidistant between the two opposed side regions. The at least two cut-out portions may be substantially castellated in shape. The floor tool may comprise more than two cut-out portions. The floor tool may comprise two, three, four or even five cut-out portions. Most preferably the floor tool has two cut-out portions. The shape and size of the cut-out portions may be shaped in such a way as to balance the internal pressure, internal air flow and reduced push force required. The visor may comprise a grip portion. The grip portion may allow the user to more easily operate the visor between the first position and the second position. The grip portion may comprise a series of ridges or cross-hatching. Preferably the grip portion comprises a raised element extending outwardly from a surface of the visor facing away from the housing. The raised element may be a lip or bar. This raised element allows for more convenient operation of the visor between the first and second position. The visor may be operable by the user’s hand but more preferably the visor may be operable by the user’s foot. This increases the convenience of switching the visor from the first to second position. The raised element may be provided on a region of the visor proximal to the upper surface. This may allow for easier access to the raised element. The raised element may preferably span at least half of the width of the visor. More preferably the raised element spans substantially the full width of the visor. This may allow the user to interact with the raised element from either the left or right of the floor tool. To make user interaction with the raised element more convenient, the raised element may be provided on the visor in the region of the upper surface of the housing. The raised element may be a solid element or a railing comprising a transverse member and a plurality of column members. The floor tool may preferably comprise a brush bar for agitating an underlying floor surface, the brush bar being provided between the two opposed side regions and immediately in advance of the recessed channel. The brush bar has a rotation centre along its longitudinal access. The rotation of the visor may be concentric to the brush bar rotation centre. This provides the advantage that the pressure applied to the sealing element is constant. This helps to prevent air leakage. The floor tool may be provided with support wheels or rollers. This may allow the floor tool to travel more easily over a floor surface. The floor tool may be incorporated into a vacuum cleaner. According to another aspect of the present invention there is provided a vacuum cleaner comprising a vacuum cleaner wand comprising a suction generating means and a collection vessel, the vacuum cleaner further comprising a floor tool comprising a housing having an upper portion, a front portion, two opposed side portions, and a rear portion, wherein an underside of the tool comprises a floor-facing base portion, the base portion being provided with a transversely extending upwardly facing recessed channel, wherein the channel is provided with an exit aperture which feeds into a suction conduit for communicating with suction generating means in the vacuum cleaning machine, the arrangement being such that, in use, fluid with entrained detritus is drawn from the tool underside into the recessed channel and out of the exit aperture, wherein a leading edge of the floor tool front portion is defined by a movable visor which is selectively moveable between a first position in which a lower region of the visor defines a first fluid gap between the floor and the visor, and a second position in which the lower region of the visor defines a second fluid gap between the floor and the visor. According to another aspect of the present invention there is provided a method of manufacturing a floor tool for a vacuum cleaner, the method comprising providing a housing having an upper region, a front region, two opposed side regions, and a rear region, wherein an underside of the housing comprises a floor-facing base portion, the base portion being provided with a transversely extending upwardly facing recessed channel, wherein the channel is provided with an exit aperture which feeds into a suction conduit for communicating with suction generating means, determining a shape, number and location of at least one cut-out portion in a front plate to achieve a desired flow characteristic, providing said at least one cut-out portion in fluid connection to the recessed channel, and providing a visor upstream of the cutout portion, wherein the visor is movable between a first position in which the lower region of the visor defines a first fluid gap between the floor and the visor and a second portion in which the lower region of the visor defines a second fluid gap between the floor and the visor. Features of one embodiment of the disclosure may be used in combination with any other embodiment. Following is a description by way of example only, and with reference to the figures of the drawings, of modes for putting the present invention into effect. In the drawings: Figure 1A is a three-quarter perspective view of the front of the floor tool with a visor in the first position. Figure 1B is a three-quarter perspective view of the front of the floor tool with a visor in the second position. Figure 2A is a section side view of the floor tool with a visor in the first position. Figure 2B is a section side view of the floor tool with a visor in the second position. Figure 3A is an underside plan view of the floor tool with a visor in the first position. Figure 3B is an underside plan view of the floor tool with a visor in the second position. Figure 4A is a front view of a front plate according to one embodiment. Figure 4B is a front view of a front plate according to a second embodiment. Figure 4C is a front view of a front plate according to a third embodiment. In figures 1 A, 1B, 2A, 2B, 3A and 3B a floor tool in accordance with the invention is designated generally as 10. The floor tool 10 features a housing 11 with an upper surface 12, opposing side surfaces 13,14, front surface 15, rear surface 16 and base 17. The housing has front wheels 18 provide at opposite edge regions of the front surface. There are two in-board rear wheels 19 which are disposed on either side of flexible conduit 25 in a rear facing recess in the rear housing surface. The wheels facilitate travel of the floor tool 10 over a floor surface to be cleaned. Best viewed in Figures 3A and 3B, the floor tool further includes a recessed transversely extending channel 20 situated in the base 17. The channel 20 spans between the two opposing side surfaces 13, 14. The channel 20 faces downwards with a generally U-shaped profile such that the opening of the channel 20 faces the floor surface to be cleaned. A brush bar 22 is provided within the channel 20. The brush bar 22 is disposed concentrically with the channel 20. In use, the brush bar 22 is driven to rotate and agitate the floor surface to be cleaned. This helps to displace and lift dirt, dust or debris from the surface, so that it can be entrained by the air drawn past the brush bar, thereby improving cleaning. The channel 20 is provided with an exit aperture 24 towards the rear centre region of the channel, that is to say in the wall of the channel closest to the rear surface 16. Said exit aperture is fluidly connected to a proximal end 26 of suction conduit 25. The suction conduit 25 has a distal end 27 which is provided with a collar feature 28. This collar feature is adapted to be connected to a vacuum cleaner wand or hose (not shown) which feeds a suction generating device. In use the vacuum cleaner suction turbine draws air through the channel opening at the base of the floor tool, through the exit aperture 24, into the suction conduit 25 and then into the vacuum cleaner wand or hose. The wand or hose feeds a collector such as a filter bag or cyclonic separator, as is conventional in the art. In this way any debris entrained by said airflow may be collected in a chamber for subsequent disposal. When travelling over a surface the floor tool may be inhibited by reduced mobility due to suction clamping. This effect is particularly common when travelling over a surface with a thick pile, such as a rug or carpet. The present invention overcomes this problem by providing an inlet aperture in the front region of the floor tool. This allows additional airflow into the recessed channel, reducing the suction force. In the embodiment displayed in figures 1A to 2B the floor tool features a front plate 32 with two cut-out portions 34. The two cut-out portions 34 define an inlet aperture allowing airflow to enter the recessed channel 20 therethrough. The front plate 32 is held in the region of the front surface 15 of the housing 11. The cut-out portions 34 will be described in more detail below with reference to figures 4A to 4C. The floor tool housing 11 further comprises a visor 29 which may be opened and closed so as to alter the size of the gap defined between the lower edge of the visor and the floor. As such the visor selectively reveals or covers the cut-out portions 34. In a first position the visor is lowered such that the gap between the visor and the floor is small. In this first position the visor 29 covers the cut-out portions 34. In a second position the visor is raised such that the gap between the visor and the floor is larger than in the first position. In this second position the visor 29 reveals the cutout portions 34. In the first position airflow is prevented from being drawn through the cut-out portions 34 whilst in the second position airflow may be drawn through the cut-out portions 34. In the embodiment of figures 1A to 2B the visor 29 is arranged to rotate about a transverse axis such that the visor 29 may be rotatably raised or lowered between the first and second positions. In other embodiments of the invention the visor 29 may be arranged to slide, rotate about a longitudinal axis or any other suitable method of transitioning between the first and second positions. A seal 36 is provided between the visor and the housing 11. This prevents air leakage. In the present embodiment, the rotation axis of the visor 29 is concentric to the axis of rotation of the brush bar 22, ensuring a constant pressure against the seal 36, thus increasing sealing effectiveness. The visor 29 is held in the first or second position by a latching mechanism. The latching mechanism generally resists movement of the visor 29 from either the first or second positions. The visor 29 can be latched in either of the first or second positions. In operation, a user may wish to move the visor 29 from the first position to the second position or vice versa. By way of an example, the user may wish to move the visor from the first position to the second position when transitioning from cleaning a hard floor surface, such as wood, to a soft surface, such as carpet. The user may opt to operate the visor 29 to prevent suction clamping. In this example, the user may rotate the visor 29 by hand, however this is inconvenient. It would be preferred if the visor could be operated by the user’s foot. To this end, a raised bar 30 is provided on the visor 29. In the embodiment of figures 1A to 2B the bar is provided in a region of the visor close to the upper surface 12 of the housing 11. This allows for easy access to the raised bar 30. However, it is possible that the raised bar 30 may be located differently, such as on a forward-facing region of the visor 29. The raised bar 30 is shown to span the full width of the visor 29, thus allowing for easy access from either side of the floor tool 10. As such the user may operate the visor 29 with either foot. The cut-out portions according to different embodiments of the invention will now be described with reference to figures 4A to 4C. With reference to figure 4A, in one embodiment the front plate 32a is provided with a pair of cut-out portions 34. These cut-out portions 34a are provided either side of and equidistant from a centreline C. The cut-out portions 34a are provided along a lower edge 40a of the front plate 32a, that is to say an edge of the front plate 32a that is closest to the surface for cleaning when in use. Each of the cut-out portions 34a are substantially castellated in shape with a pair of oppositely inclined edges 341,342 separated by a horizontal edge 343 which is substantially parallel to the lower edge 40a. As such, the cut-out portions 34a are substantially trapezoidal in plan. Referring now to figure 4B, in an alternative embodiment the front plate 32c comprises a pair of cut-out portions 34b located distal from the centreline C. The cutout portions 34b are substantially triangular in cross-section with an inclined edge 344, 345 extending from the front plate lower edge 40b to side edges 41 b, 42b respectively. Referring now to figure 4C, in another alternative embodiment the front place 32c comprises two cut-out portions 34c provided distal from the centreline C. The cut-out portions 34c comprise an inclined edge 346, 348 rising from the front plate lower edge 40c and a horizontal edge 347, 348 spanning from the respective inclined edge 346, 348 to front plate side edges 41c, 42c. Whilst the above embodiments each feature two cut-out portions although of course any number may be provided. In each of the above-described embodiments the cut-out portions are provided towards the surface to be cleaned. This allows for ingress of large debris items into the recessed channel 20 which would otherwise be pushed by the floor tool 10 in a ploughing effect, thereby allowing the floor tool 10 to collect larger debris than conventional vacuum cleaner arrangements. However, it will be appreciated that one or more cut-out portions may be provided away from the surface to be cleaned in combination with, or as an alternative to, cut-out portions at surface level. The number, size, location and shape of the cut-out portions may be selected to give desirable airflow therethrough and thus a desirable reduction in suction force. For example, increasing the size and / or number of cut-out portions will tend to increase airflow into the recessed chamber, reducing suction force. These parameters may be altered to provide a floor tool which has both effective cleaning characteristics and a comfortable push force.

Claims

1. A floor tool for a vacuum cleaning machine, the floor tool comprising a housing having an upper portion, a front portion, two opposed side portions, and a rear portion, wherein an underside of the tool comprises a floor-facing base portion, the base portion being provided with a transversely extending upwardly recessed channel, wherein the channel is provided with an exit aperture which feeds into a suction conduit for communicating with a suction generating means, the arrangement being such that, in use, fluid with entrained detritus is drawn from the tool underside into the recessed channel and out of the exit aperture, wherein a leading edge of the floor tool front portion is defined by a movable visor which is selectively moveable between a first position in which a lower region of the visor defines a first fluid gap between the floor and the visor, and a second position in which the lower region of the visor defines a second fluid gap between the floor and the visor.

2. A floor tool according to claim 1 wherein the visor is provided upstream of an inlet opening which feeds into the channel.

3. A floor tool according to either of claim 1 or claim 2 wherein the visor comprises a lower front plate provided with at least one cut-out portion.

4. A floor tool according to any of the preceding claims wherein the first position is a visor lowered position, and the second position is a visor elevated position.

5. A floor tool according to any of the preceding claims wherein the visor is rotationally moveable between the first position and the second position.

6. A floor tool according to either of claim 4 or 5 wherein the visor has a profile which provides a camming surface configured so when the visor is in the lowered position the fluid gap is uniform across the leading edge of the tool.

7. A floor tool according to claim 6 wherein the gap across the leading edge is tightened in the lowered position as compared to when the visor is in the elevated position.5 8. A floor tool according to any of claims 3 to 6 wherein the platecomprises one or more discrete cut-out portions which each provide a locally enlarged fluid gap when the visor in in the raised position.

9. A floor tool as claimed in claim 8 wherein the visor cut-outs provide 10 enhanced fluid flow10. A floor tool as claimed in claim 8 or 9 wherein there are at least two spaced part cut-out portions.15 11. A floor tool according to claim 10 wherein the at least two cut-outportions are substantially the same size and / or shape.

12. A floor tool according to claim 10 or 11 wherein the floor tool comprises a centreline equidistant between the two opposed side regions and the 20 at least two cut-out portions are provided symmetrically about said centreline.

13. A floor tool according to any one of claims 10 to 12 wherein the atleast two cut-out portions have a substantially trapezoidal plan.25 14. A floor tool according to any of the preceding claims wherein the floortool further comprises a brush bar for agitating the underlying floor surface, the brush bar being provided between the two opposed side regions and in advance of the recessed channel, and the brush bar having a rotational axis along its longitudinal centreline.3015. A floor tool according to claim 14 wherein a rotational pivot of the visor is concentric with the brush bar rotational axis.

16. A floor tool according to any of the preceding claims and provided with support wheels or rollers.

17. A floor tool according to any of the preceding claims wherein the visor comprises a grip portion for moving the visor between the first and second positions.

18. A floor tool according to claim 17 wherein the grip is configured as a raised horizontal bar element.

19. A floor tool according to claim 18 wherein the raised bar element spans the width of the visor.

20. A floor tool according to either of claims 18 or 19 wherein the raised bar element is provided on an upper surface of the visor.

21. A floor tool according to any of the preceding claims wherein the floor tool further comprises a sealing element between the visor and the housing for providing an airtight seal therebetween.

22. A floor tool according to any of the preceding claims wherein the suction generating means is provided in the vacuum cleaning machine or the floor tool.

23. A vacuum cleaning device comprising a floor tool according to any of the preceding claims.

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