FIELD OF THE INVENTION

This invention relates to a wet floor cleaner, in particular it relates to a rotary brush for use in the head of a wet floor cleaner.

BACKGROUND OF THE INVENTION

Wet vacuum cleaners are known in which the cleaning head (often known as the "nozzle") has two counter-rotating brushes. Suction is applied at least to the space between the brushes to draw up liquid from the floor that has been delivered to the floor by the vacuum cleaner. The brushes contact the floor to perform a scrubbing action. There are also known cleaning head designs with a single rotary brush.

A first issue with the cleaning head is that it should have a low profile so that it can fit underneath items of furniture. This means in particular that the brushes should have a small diameter, for example typically in the range 30mm to 60mm. These small dimensions make it difficult to fit a drive motor for a rotary brush inside the brush itself, but it is known that this would be a desirable location for the motor drive. This not only uses space which has no other purpose, but it also makes it easier to avoid increasing a width of the cleaning head beyond the width of the rotary brush.

A second issue is that wet vacuum cleaners are hard to clean after use. Cleaning after use is a prerequisite to avoid bacterial growth and unpleasant odors after use. The user perceives both as unhygienic.

To overcome this problem, some wet vacuum cleaners are equipped with a cleaning tray that is used to rinse the appliance after use. For example, EP2672872 discloses a tray to clean the rotary brush of a wet vacuum cleaner. Alternatively, the rotary brushes may be removed from the cleaning head for cleaning externally of the cleaning head.

In all cases, removal of the cleaning brushes is desirable so that they can be replaced when they are worn. The need for a removal interface also takes up space, again making the integration of a motor into the rotary brushes themselves more challenging.

The invention aims to address these issues.

DE 202014001492 discloses a floor cleaner with roller brushes, having internal drive motors within the interior space of the roller brushes, and a rotary coupling between the roller brush and its internal motor. SUMMARY OF THE INVENTION

The invention is defined by the claims.

According to examples in accordance with an aspect of the invention, there is provided a rotary brush for a wet floor cleaner, for mounting in a head of the wet floor cleaner, the rotary brush comprising: an inner core which is cylindrical and hollow with an inner surface and an outer surface; and a cleaning member disposed around the outer surface of the inner core, wherein the inner core comprises at least one rib projecting inwardly from the inner surface and extending along a full length of the inner surface parallel to the cylinder axis.

This rib is for transferring torque from a drive arrangement (e.g. inside the inner core) to the rotary brush. The rib can have a small size so that it does not take up a significant amount of space of the inside of the inner core. The inner core is simple to manufacture and it may for example have a constant cross section along its length (so that it may be extruded).

The inner core may comprise two ribs extending along the length of the inner surface, each parallel to the cylinder axis and spaced 180 degrees apart. This provides a more distributed transfer of torque.

The, or each, rib for example has a width in the range 1mm to 5mm and a height in the range 1mm to 5mm, preferably 1 to 3mm.

The width is in a circumferential direction around the inner core and the height is in a radial direction. These dimensions are sufficiently small that only a small volume within the inner core is taken up by the ribs.

The inner core for example comprises an extruded metal tube such as an aluminum tube. This means it may be formed with a thin wall (for example in the range 0.5mm to 2mm) so that a maximum of space is retained inside the inner core, in particular for housing the motor to drive the rotary brush. It also means the rib can have a low profile as explained above, again taking up a small amount of internal space.

The rotary brush may further comprise a first interface component for projecting into the inner core at a first end of the rotary brush, the first interface component comprising a channel for engaging with the rib.

The first interface component may be considered to be part of the rotary brush in that it may be sold with the rotary brush as a combined unit for replacement at the same time.

The first interface component for example comprises a first cylindrical projection having at least one channel for receiving the at least one rib, and the first interface comprises a bearing to enable free rotation of the first cylindrical projection. Thus, one end of each rotary brush has a bearing to enable free rotation. The rotary brush is driven at the opposite end. The bearing is for example replaced with the brush, since the bearing may have a similar lifespan, due to the operation in a wet environment with cleaning chemicals.

The rotary brush may further comprise a second interface component for projecting into the inner core at a second end of the rotary brush, the second interface component also comprising a channel for engaging with the rib.

The second interface component may also be considered to be part of the rotary brush in that it may be sold with the rotary brush as a combined unit for replacement at the same time. It may for example comprise a cover for covering a motor, and the motor is not replaced with the rotary brush.

The rotary brush is removable from the cleaning head, by disengaging it from the housing. The second interface component is basically a housing over the motor. The two interface components engage with the rib of the rotary brush and the second interface component thereby transfers torque to the inner core of the rotary brush.

The invention also provides a cleaning head for a wet floor cleaner comprising: a housing; at least one rotary brush as defined above extending across a width of the housing; a suction channel for delivering suction to at least a space in the vicinity of the at least one rotary brush; and a motor housed within the second interface component and inside the inner core of the at least one rotary brush, for driving the rotary brush.

The motor is housed inside the inner core of the rotary brush.

The cleaning head for example comprises first and second rotary brushes each extending across a width of the housing with parallel rotation axes, and side by side in a length direction of the cleaning head. The first and second rotary brushes are then each removable from the cleaning head by decoupling the rotary brush from the motor.

The suction channel is for delivering suction to at least a space between the first and second rotary brushes.

The cleaning head may comprise a respective motor located inside the inner core of each of the first and second rotary brushes. The motors are for example for driving the first and second rotary brushes in opposite rotation directions.

The first interface component is for example removably connectable to an opening in the housing, wherein the opening functions as a removal port for removing the respective rotary brush from the housing. Thus, the first interface component is decoupled from the housing to expose the opening, through which the rotary brush (i.e. the core, the cleaning member and the first interface component itself) can be removed laterally. The first interface component for example comprises a bayonet coupling for connection to the housing.

The second interface component for example comprises a second cylindrical projection, and the second interface component houses the motor and a drive coupling which is rotated by the motor. When the rotary brush is removed, the second interface component is atached to the rotary brush but the motor remains atached to the housing.

Thus, an end of each rotary brush (opposite the bearing) has a drive coupling to be driven by the motor arrangement located within the inner core of the rotary brush..

The motor preferably comprises, for the, or each, rotary brush, an external interface comprising a set of three protrusions angularly spaced apart around an end face of a motor drive shaft, and the drive coupling comprises a corresponding set of three protrusions angularly spaced around an internal end of the second cylindrical projection.

Thus, the main body of the motor is static, and it drives an external interface, which in turn drives the drive coupling. The drive coupling is coupled to rotate the inner core of the rotary brush.

A support wheel arrangement is preferably provided for mounting the housing at a minimum spacing over the floor to be cleaned.

The invention also provides a wet floor cleaner comprising: the cleaning head as defined above; and a pump for delivering suction to the suction channel.

The wet floor cleaner for example further comprises a water reservoir for delivering water to the cleaning head.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

For a beter understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

Figure 1 shows a known layout for a wet floor cleaner head;

Figure 2 shows another known layout to achieve a smaller and more compact cleaning head;

Figure 3 shows a cross section through one of the rear support wheels of the cleaning head of Figure 2;

Figure 4 shows an example of the rotary brush;

Figure 5 shows an example of the dimensions of the rotary brush; Figure 6 shows a cleaning head;

Figure 7 shows the first interface component more clearly;

Figure 8 shows the second interface component more clearly;

Figure 9 shows a drive coupling;

Figure 10 shows an end of the motor assembly in the form of an external interface; Figure 11 shows a replaceable rotary brush unit in cross section;

Figure 12 shows the cleaning head with one rotary brush removed and the other in place;

Figure 13 shows the cleaning head housing with one rotary brush removed, leaving the other in place.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention will be described with reference to the Figures.

It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

The invention provides a rotary brush for a wet floor cleaner. The brush has a cylindrical inner core and a cleaning member disposed around an outer surface of the inner core. The inner core comprises at least one rib projecting inwardly from an inner surface and extending along a length of the inner surface parallel to the cylinder axis. This is used to transfer torque from a motor, which is preferably housed within the inner core, to the brush, while taking up a minimum amount of space.

The invention relates to a rotary brush for a cleaning head of a wet floor cleaner. The general configuration of the cleaner head will first be explained.

Figure 1 shows a known layout for a wet floor cleaner head 10, viewed from the underside. The head comprises a housing 12 which supports a first, front brush 14 and a second, rear brush 16. A set of four support wheels 18 is arranged in a rectangular configuration behind the rear brush 16.

A main direction of motion of the cleaning head in use is parallel to a length direction of the cleaning head, perpendicular to the width direction of the housing as defined above. The main direction of movement is shown by the large arrow. This motion tends to roll the brushes over the floor. Figure 2 shows another known layout to achieve a smaller and more compact cleaning head, for example more suitable for a battery-operated device.

The head 10 again comprises a housing 12 which supports a first, front brush 14 and a second, rear, brush 16.

The housing 12 has width W between first and second side walls 20, 22 and a length L, the length being parallel to the intended main direction of movement of the cleaning head over a floor to be cleaned.

The first and second rotary brushes 14, 16, each extend across the width of the housing between the first and second side walls 20, 22, with parallel rotation axes, and side by side in the length direction. A suction channel is provided for delivering suction to at least a space 24 between the first and second rotary brushes 14, 16. Indeed the suction will be applied to the general volume of the housing.

This definition of the width direction and length direction of the cleaning head is applicable throughout this text.

The support wheel arrangement in this design comprises a first support wheel 30 in the space 24 between the first and second rotary brushes and a second support wheel 32 in the space 24 between the first and second rotary brushes. The outer faces of the wheels are approximately flush with the side walls.

Mounting the first and second support wheels between the rotary brushes saves space. There is a third support wheel 34 behind the first and second rotary brushes (it could instead be in front) in the length direction, and a fourth support wheel 36 side-by-side with the third support wheel 34.

Figure 3 shows a cross section though one 34 of the rear support wheels 34,36 of the cleaning head of Figure 2, and shows the support wheel 30 further back (behind the plane of the cross section). It shows that the first and second rotary brushes 14, 16 are driven in opposite rotation directions, so that they move upwardly where they face each other, in the space 24. A suction channel 40 delivers suction to at least the space 24 between the first and second rotary brushes.

The rotary brushes are driven by a drive arrangement which may comprise single motor and a belt drive for driving the two rotary brushes. Alternatively, each rotary brush may have its own a respective motor mounted in the core of the respective rotary brush.

The cleaning head also has a fluid delivery arrangement (not shown) for delivering fluid to the first and/or second rotary brushes. Fluid may for example be delivered to the rotary brush 16 at the back of the cleaning head from a reservoir formed in a main housing of the vacuum cleaner.

The rotation of the first and second brushes results in the cleaning head blowing outwardly from the front and back. It also creates an under pressure in the space between the brushes (since air is removed continuously), which creates lateral air suction.

The mounting of the support wheels by the housing defines a minimum spacing S between a bottom surface of the housing and the floor surface. This minimum spacing is for example in the range 1.5 mm to 3 mm. The rotary brushes project below the level of the floor (when the floor is not present) so that the tufts are deformed by the presence of the floor. This defines a floor indentation and it is part of the water gathering function, as explained above.

Figure 3 also shows front and rear spoilers 39 for guiding water which has been sprayed against the housing back to the brushes.

This invention relates in particular to the design of the rotary brush and in particular the invention relates to a design of the rotary brush which facilitates the mounting of the motor in the brush core.

Figure 4 shows an example of the rotary brush 14. The rotary brush 14 comprises an inner core 40 which is cylindrical and hollow with an outer surface 42 and an inner surface 44. A cleaning member 46 is disposed around the outer surface 42 of the inner core 40, for example comprising radially directed cleaning tufts. The cleaning member may be entirely conventional.

The inner core comprises at least one rib 48 projecting inwardly from the inner surface 44 and extending along a length of the inner surface parallel to the cylinder axis. In the example shown, the inner core comprises two ribs 48 extending along the length of the inner surface, each parallel to the cylinder axis and spaced 180 degrees apart. There may even be three or four ribs.

The rib or ribs are for transferring torque from a motor (located within the inner core) to the rotary brush. The ribs are preferably as small as possible to enable the required torque transfer. For example, each rib has a width (in the circumferential direction) in the range 1mm to 5mm and a height (in the radial direction) in the range 0.75mm to 5mm, such as 1mm to 3mm.

The inner core 40 is for example an extruded metal component, with a thin wall width for example in the range 0.5mm to 3mm. The inner core is thus simple to manufacture. It may be formed of aluminum or other metal.

The inner core is end-to-end symmetric so that it may be fitted in either end-to-end orientation. The rib or ribs thus extend the full length of the inner core, from one end to the other end.

The inner core thus has a constant cross section along its length and can thereby be extruded.

Figure 5 shows an example of the dimensions of the rotary brush 14. In this example, it has a length of 250.5mm, an outer diameter of 55 5mm and an inner diameter of the core of 30.4mm. The rib has a circumferential with of 1 5mm and a radial height of 1.0mm.

Figure 6 shows a cleaning head 10 comprising a housing 12 for housing two of the rotary brushes of Figure 4, each extending across a width of the housing 12.

Each rotary brush is removable from the housing. In Figure 6, part of one rotary brush is shown as removed (in particular only the inner core and cleaning member) and the other rotary brush 16 is in place. At each end of the rotary brush, there is an interface component. The two interface components for the removed rotary brush are shown in Figure 6 although as will be clear from the description below, the interface components are in fact removed with the brush).

A first interface component 60 is for projecting into the inner core of the rotary brush at a first end of the rotary brush. The first interface component comprises a first cylindrical projection with a respective channel 62 for engaging with each rib. The first interface component 60 comprises a bearing to enable free rotation of the first cylindrical projection about a static core.

The whole of the first interface component 60 may in fact be considered to be part of the rotary brush in that it may be sold with the rotary brush as a combined unit for replacement at the same time. The bearing is thus replaced with the brush, since the bearing may have a similar lifespan, due to the operation in a wet environment with cleaning chemicals. The way the brush and its attached first interface component is removed from the cleaning head is described below.

A second interface component 70 is for projecting into the inner core at a second end of the rotary brush. The second interface component also comprises a second cylindrical projection with a respective channel 72 for engaging with each rib.

The second interface component comprises a projection which is thus located, in use, inside the inner core of the respective rotary brush, for driving the rotary brush. The second interface component 70 may also be considered to be part of the rotary brush in that it may be sold with the rotary brush as a combined unit. However, the second interface component fits over the drive motor, which is preferably not replaced with the rotary brush.

The rotary brush is removable from the cleaning head, by separating the second interface component from the motor that it covers. Thus, the motor remains in place as a fixed part of the cleaning head. The interface components both engage with the ribs of the rotary brush. The second interface component 70 thereby transfers torque from the motor to the inner core of the rotary brush. The first interface 60 allows rotation of the inner core of the rotary brush around a central static part which fixes to the housing, for example with a bayonet coupling.

Figure 7 shows the first interface component 60 more clearly. It comprises a cylindrical projection 61 with the channel 62, and a head part 64 which includes a bayonet coupling 66. The head part 64 can be locked into an opening in the housing, so that the rotary brush can be removed from the housing, with the first interface component 60 remaining attached to the core of the rotary brush.

Figure 8 shows the second interface component 70 more clearly. It has a cylindrical body 71 which fits over the motor housing. The cylindrical body includes the channel 72.

Note that the channels in both interface components may comprise a slit which extends fully through a side wall and the term "channel" should be understood accordingly as including a closed channel or an open channel. An open channel (slit) can be seen in Figure 9, where the rib 48 of the brush core 40 is visible. The motor rotates a drive coupling, within the general cylindrical projection 71 of the second interface component, and which is rotated by the motor.

The drive coupling 90 is shown in Figure 9 at the end of the cylindrical housing 71 of the second interface component. It is in the form of a cap which sits over the end of the static motor assembly within the cylindrical body 71 of the second interface component. An end of the motor assembly engages with an inner surface at the end of the cap to cause the cap to rotate. The cap is fixed inside (or integrally formed with) the cylindrical projection 71. Rotation of the cylindrical projection 71 is then transferred to the brush by the ribs and channels.

Figure 10 shows the end of the motor assembly, in the form of an external interface 100 comprising a set of three protrusions 102 angularly spaced apart around an end face of the motor drive shaft.

The drive coupling 90 of Figure 9 comprises a corresponding set of three protrusions 92 angularly spaced around an internal end of the second cylindrical projection.

Thus, the main body of the motor is static, and it drives an external interface 100, which in turn drives the drive coupling 90. The drive coupling is fixed to (or integral with) the main cylindrical body 71 of the second interface 70 and is coupled to rotate the inner core of the rotary brush.

The arrangement of projections 92,102 enables the rotary brush to be aligned easily with the second interface component during fitting of the rotary brush to the housing. The projections on one side engage with the spaces between projections on the other side.

As mentioned above, the first interface component (the bearing) may be considered a part of the rotary brush in that it can be replaced with the brush. Similarly, the outer cylindrical housing 71 of the second interface component, and the drive coupling 90, may also be considered to be part of the rotary brush.

Figure 11 shows the replaceable unit in cross section. It comprises the inner core 40, the outer brush part 46, the first interface component 60 (the bearing and bayonet coupling), the second interface component 70, and the drive coupling 90. Note that the cross section is taken through the ribs and hence through the slits in the second interface component, hence the main cylindrical part 71 is at the end of the brush is not visible in this cross section. The removal of the rotary brush involves separating the drive coupling 90 (which is removed) from the external interface 100 (which remains in place), thus leaving the motor 120 and its external interface 100.

Figure 12 shows the cleaning head with one rotary brush removed and the other 16 in place. It shows that the motor housing 120 and the external interface 100 remain in place.

Figure 13 shows the cleaning head housing 12 with one rotary brush removed, leaving the other 16 in place. The housing has openings 130 which functions as a removal port for removing a rotary brush from the housing. The housing is shown as generally rectangular so that the side walls 20, 22 are parallel, but the side walls may be non-parallel for example with a triangular or trapezium shaped housing. The first and second brushes may have the same length (in the width direction of the head) or they may have different lengths. The cleaning head is preferably part of wet vacuum cleaner comprising a pump for delivering suction to the suction channel of the cleaning head and a fluid reservoir delivering cleaning fluid to the cleaning head.

The example above is based on a cleaning head with two rotary brushes. However, cleaning heads with a single rotary brush are also possible (e.g. with a mop part behind the brush) and the arrangement of the invention may be applied to a single rotary brush.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to".

Any reference signs in the claims should not be construed as limiting the scope.