GB2602070A

GB2602070A - Floor cleaner

Info

Publication number: GB2602070A
Application number: GB2019976.6A
Authority: GB
Inventors: Stuart Cole David
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2020-12-17
Filing date: 2020-12-17
Publication date: 2022-06-22
Also published as: CN116648176A; GB202019976D0; WO2022129858A1

Abstract

A floor cleaner that dispenses cleaning fluid and collects dirty liquid comprises a cleaning head which includes a plurality of driven cleaning elements 126L, 126R , the cleaning elements each comprising a cleaning pad for engaging and cleaning the floor in combination with the delivered cleaning liquid. First and second cleaning elements are driven to counter-rotate and the areas swept out by the rotation the pads overlap. The pads include respective lobes 129 which, in use, enter the region of overlap as the pad is rotated. The pads include multiple concave regions 133, each concave region being located between a pair of adjacent lobes of the pad, such that each concave region of one of the first and second pads is paired with a corresponding lobe of the other of the first and second pads, the concave region remaining outside of the overlap region as the corresponding paired lobe moves through the overlap region.

Description

Floor cleaner

Field of the Invention

The present invention concerns a floor cleaner. More particularly, but not exclusively, this invention concerns a vacuum cleaner for washing and cleaning a floor with a cleaning liquid, which may be referred to as a wet floor cleaner.

Background of the Invention

Various types of floor cleaner are available. They include "dry" floor cleaners such as vacuum cleaners, and "wet" floor cleaners. Some wet floor cleaners of the prior art apply a cleaning fluid to the floor as part of the cleaning process and include a reservoir for holding such cleaning fluid. Some wet floor cleaners of the prior art include cleaning elements arranged to be in contact with the floor and for agitating the cleaning fluid once applied to the floor. Such cleaning elements may be driven via one or more electric motors. The wet floor cleaner may also include a vacuum pump or fan which removes waste liquid from the floor.

CN206586900U discloses a wet floor cleaner having a cleaner head with a scrubbing device comprising adjacent generally circular cleaning discs which in use are driven to rotate in opposite directions. Cleaning liquid is delivered to the floor via outlets in the cleaner head. A liquid suction device is arranged on the cleaner head and located behind the scrubbing device, and is used for sucking away liquid on the surface to be cleaned. Rotational movement utilising generally round cleaning pads makes it difficult to clean a floor in the region in or near a corner formed by two perpendicular walls. Also the rubbing motion between pad and floor increases with radial distance from the centre of rotation, meaning that floor beneath the centre of rotation will be cleaned less effectively that areas nearer the periphery of the pad.

Other floor cleaners having more than one driven cleaning device, in the form 30 of a pad which is moved over the floor when cleaning, are known. GB389285A discloses a pair of such pads which are rectangular and reciprocate on a straight line path in use, moving in opposite directions as they do so. The pads move left and right, such that the area in the fore-aft direction cleaned by the pads, absent any extra -2 -movement caused by the operator of the cleaner, is limited by the length of the pads in the fore-aft direction.

KR20010087031 shows a floor cleaner with square pads which rotate to and fro about spaced apart axes. There is an open area between the pads at which cleaning liquid is sprayed onto the floor. The region of the floor at the gap between the pads does not appear to be covered by the rotating motion of the pads, other than by means of the operator moving the whole floor cleaner laterally over the floor.

In all of the above-described prior art, the cleaning elements in contact with the floor are flat-bottomed remaining co-planar with the surface being cleaned and utilise either rotational movement of pads about a fixed axis or translational reciprocating movement along a straight line path. Dirt will tend to be moved to the exterior of the area being swept out by the pads. That might make it difficult to clean areas near walls or in corners.

The present invention seeks to mitigate one or more of the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved floor cleaner.

Summary of the Invention

The present invention provides, according to a first aspect, a floor cleaner for cleaning a floor. The floor cleaner comprises a reservoir for storing cleaning liquid. The floor cleaner comprises a cleaning head which is arranged to deliver cleaning liquid received from the reservoir to the floor, and to suck used cleaning liquid from the floor. The cleaning head includes a plurality of driven cleaning elements, the cleaning elements each comprising a cleaning pad for engaging and cleaning the floor in combination with the delivered cleaning liquid. A first of the cleaning elements is arranged to be driven relative to the cleaning head with a component of rotational motion about an axis transverse (e.g. perpendicular) to the floor as a second of the cleaning elements is arranged to be driven relative to the cleaning head with a component of rotational motion about an axis transverse (e.g. perpendicular) to the floor in the opposite direction. For example, the first element may rotate clockwise as the second element rotates anticlockwise. The area swept out by the rotation of a first cleaning pad of the first cleaning element overlaps with the area swept out by the rotation of a second cleaning pad of the second cleaning element, thus defining an -3 -overlap region between the first and second pads. Having an overlap region like this enables a wider area to be covered by the rotating pads without there being gaps between the areas covered by the respective pads, which might otherwise reduce the effectiveness of the cleaner.

In embodiments, the cleaning head may have a generally rectangular footprint having its shortest edge in the fore-aft direction in which a user might typically move the cleaner over the floor, with the rotating pads arranged side by side along the longest edge of the rectangular footprint. Having an overlap region between the rotating pads may enable a wider area to be covered by the rotating pads without there being gaps between the areas covered by the respective pads, which might otherwise reduce the effectiveness of the cleaner. This overlap region is made possible in embodiments of the invention by means of the shape and movement of the respective pads, as will now be explained.

The first cleaning pad includes multiple lobes each of which, in use, enter the overlap region, as the pad is rotated. Similarly, the second cleaning pad includes multiple lobes each of which, in use, enter the overlap region, as the pad is rotated. The pads include multiple concave regions, each concave region being located between a pair of adjacent lobes of the pad, such that each concave region of one of the first and second pads is paired with a corresponding lobe of the other of the first and second pads, the concave region remaining outside of the overlap region as the corresponding paired lobe moves through the overlap region. Having concave regions paired with lobes in this manner allows a beneficially sized overlap region to be formed without collision between the pads, in a manner that may be particular suited to certain floor cleaning applications. In embodiments, the concave regions may for example assist with moving liquid or debris from out of the region of the pad so that it can be sucked up by a part of the cleaner spaced apart from the pads. While in some embodiments it may be preferred for there to be no sharp corners formed by the concave regions of the pad, in other embodiments, the concave regions may be formed at least in part by interconnected straight edges, possibly joining each other at sharp corners.

Having two or more lobed pads rotating next to each other in the context of embodiments relating to a wet floor cleaner may assist in the delivery of liquid to the floor, particularly in the region of overlap between the pads. It is preferred for the pads to be so shaped that for the time taken to complete a full rotation of the pads, the -4 -proportion of time when at least part of a lobe of at least one pad is in the overlap region is greater than 75%. The proportion of time when at least part of a lobe is in the overlap region may be some embodiments be more than 90% of the time and possibly substantially all the time.

In some embodiments, the lobes may each comprise a convexly shaped tip, which may be in the form of a smoothly curved tip. It may be that the shape of the planform of each cleaning pad is in the form of a closed loop formed by a smooth curve. The smallest radius of curvature of the shape of one of the lobes may be within 10% to 1000% of the smallest radius of curvature of the concave region paired with the lobe.

In some embodiments, the lobes may each comprise a pointed tip, which may terminate at a sharp corner or may be rounded.

There may be more than three lobes. Each pad may have only three lobes (e.g. the number of all lobes of the pad may be equal to three). There may be embodiments in which too many lobes would be problematic; for example there may be considerations such as integrity of the pad and risk of damage to a relatively small lobe. In such cases, it may be preferred to have six or fewer lobes. In other embodiments, for example ones in which it is desired to have the lobes of one pad intermesh with the lobes of another pad, more than six lobes might be desirable. In such cases, it may be that there are nevertheless fewer than 20 lobes on each pad.

It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention.

Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which: Figure 1 shows a floor cleaner of a type compatible with embodiments of the invention; Figure 2 shows a dock capable of receiving the floor cleaner of Figure 1; Figure 3 shows schematically the functions of the floor cleaner of Figure 1; -5 -Figure 4 shows a cleaner head for a floor cleaner according to a first embodiment of the invention, Figures 5 to 13 show the cleaning pads of the cleaner head of the first embodiment in successive positions as they move during use; Figure 14 shows a rotating cleaning element for a cleaner head for a floor cleaner according to a second embodiment of the invention; Figure 15 shows a rotating cleaning element for a cleaner head for a floor cleaner according to a third embodiment of the invention; Figure 16 shows a rotating cleaning element for a cleaner head for a floor cleaner according to a fourth embodiment of the invention; Figure 17 shows a rotating cleaning element for a cleaner head for a floor cleaner according to a fifth embodiment of the invention; and Figure 18 shows a rotating cleaning element for a cleaner head for a floor cleaner according to a sixth embodiment of the invention.

Detailed Description

Embodiments of the present invention relate to a floor cleaner for cleaning a floor. The following description relates to features that are typically present in a given embodiment of the invention, but it will be understood that there may be embodiments not having such features. The skilled person will appreciate that the accompanying claims may be amended to add or remove features now described. The one or more specific embodiments relating to the accompanying Figures are described in detail later.

The floor cleaner comprises a cleaning head including at least one driven cleaning element for engaging and cleaning the floor. The floor cleaner may comprise only two such cleaning elements. In other embodiments, the floor cleaner may comprise more than two cleaning elements.

The floor cleaner may be in the form of a vacuum cleaner. The cleaning head may be arranged to suck dirt from the floor in use. The driven cleaning element(s) may be arranged to engage and clean the floor by means of agitating dirt so that it can be more readily sucked from the floor. For example, the driven cleaning element may comprises one or more brushes, for example arranged around its periphery. -6 -

The floor cleaner may be a wet floor cleaner. The floor cleaner may comprise a reservoir for storing cleaning liquid. The cleaning head may be arranged to deliver cleaning liquid, for example received from such a reservoir, to the floor. It may be that the liquid is gravity fed. It is preferred however for the liquid to be pumped, for example under the control of a control unit that forms part of the floor cleaner. The cleaning element(s) may be arranged to engage and clean the floor in combination with delivered cleaning liquid. The cleaning head of the floor cleaner may be arranged to remove used cleaning liquid from the floor, for example via suction. Thus, the cleaning head may be arranged (a) to deliver cleaning liquid received from a reservoir of the floor cleaner to the floor, so that the cleaning element(s) engage and clean the floor in combination with the delivered cleaning liquid, and (b) to suck used cleaning liquid from the floor. The floor cleaner may include a waste tank for receiving used cleaning liquid sucked from the floor by the cleaning head.

The floor cleaner may have its own electrical power supply for driving a motor that is arranged to provide suction, for example by the motor driving a vacuum pump or fan. The floor cleaner may have its own electrical power supply for driving the one or more cleaning elements. The floor cleaner may contain one or more batteries, for example in the form of a rechargeable battery pack.

Each cleaning element may comprise a pad, for example a cleaning pad and/or an absorbent pad. When the floor cleaner is in the form of a wet cleaner, cleaning liquid may be delivered to the floor via the cleaning pad(s) of the cleaning element(s). Used cleaning liquid may be sucked from the floor via the cleaning pad(s) of the cleaning element(s). Each cleaning pad may comprise an open cell foam material, for example which allows liquid to drain therethrough. Each cleaning pad may additionally or alternatively comprise holes or channels in the body of the pad to allow liquid to drain therethrough.

The cleaner head may comprise multiple suction inlets arranged to be adjacent to the floor when the cleaner is in use, the suction inlets being spaced apart from the cleaning elements and being provided to suck used cleaning liquid from the floor.

The cleaner head may comprise multiple outlets arranged to be adjacent to the floor when the cleaner is in use, the outlets being spaced apart from the cleaning elements and being provided to deliver cleaning liquid to the floor. It will be appreciated that in some embodiments, liquid may be delivered via the pads and sucked from the floor -7 -via a different route, and that in other embodiments, liquid may be sucked from the floor via the pads but delivered to the floor via a different route.

Each cleaning element may be moved relative to the floor with a component of rotational motion, for example about an axis (which itself may move or be stationary relative to the cleaning head) that may be non-parallel to the floor, and/or upright (that is, not necessarily always perfectly vertical or perpendicular to the plane of the floor when in use, but substantially vertical, or at least more vertical than horizontal). Each cleaning element may be moved relative to the floor with a component of translational motion, for example parallel to the floor. Each cleaning element may be moved relative to the floor around a closed path, for example which is fixed in position relative to the cleaning head. Each cleaning element may be arranged to be moved to and fro, in one direction and then in an opposite direction, and/or with an oscillating motion. The oscillating motion may for example include moving the cleaning element with movement along a path or in a given direction, for a period of time, and then moving the cleaning element with an opposite movement, for example for an equal period of time, before reversing the movement again, and repeating. Each cleaning element may be arranged to have cyclical motion, for example with the same set cycle of motion being repeated cyclically.

The cleaning element, and/or the pad associated with the cleaning element, may have a shape that includes a pointed corner. The pointed corner may be rounded.

The pointed corner may form an apex. The shape may have at least three pointed corners. The shape may have rotational symmetry. The shape may be a quadrilateral with three edges that are at right angles to at least one of the other two edges. The shape may have two parallel edges. The shape may have one edge that is at an acute angle to the opposite edge, for example a slanted edge. One cleaning element, and/or the pad associated with the cleaning element, may have a shape with a portion (for example a curved portion or a slanted edge) that, in use is adjacent to a correspondingly shaped portion of the shape of another, for example paired, cleaning element/pad.

In the case where there are at least two cleaning elements, one of the cleaning elements may be arranged to be a master cleaning element and another cleaning elements may be arranged to be a slave cleaning element, such that the master cleaning element is arranged to drive the slave cleaning element. The cleaning elements may be arranged to be driven relative to the cleaning head such that as a first -8 -of the cleaning elements rotates in a clockwise direction, a second of the cleaning elements rotates in an anticlockwise direction or such that as the first cleaning element moves in one direction, the second cleaning element moves in the opposite direction. In the case where there are multiple cleaning elements, the cleaning elements (for example the pads of the cleaning elements) are preferably so shaped that the footprint of the area swept out by a first cleaning element and the footprint of the area swept out by a second cleaning element have a shared boundary or overlap. Such a geometry reduces the chance of a region of the floor between the pads not being adequately cleaned. The pads of the cleaning elements may be compressible or deformable to allow for the pads to touch during use, whilst reducing the risk of finger trapping or trapping other foreign objects. For such a reason, the rigid bodies of the cleaning elements may be arranged to always be spaced apart during use. The shape of each cleaning element may be the same. The shape of one cleaning element may be a mirror image of another cleaning element, for example a paired cleaning element.

In the case where the cleaner is a wet floor cleaner, the cleaning head may further comprise a barrier member for retaining cleaning liquid at least partly within a footprint of the cleaning head. The barrier member may for example comprise a squeegee device. The cleaner head may comprise a first barrier member on one side of the foot print of the cleaner head and a second barrier member on an opposite side of the foot print of the cleaner head. The cleaner head may be open (e.g. no barrier member) on the other sides of the footprint of the cleaner head. Each barrier member may be movably mounted on the cleaning head, so that it lifts off from the floor when moved along the floor as the leading barrier member and is nearer to the floor (e.g. in contact with the floor) when moved along the floor as the trailing barrier member.

With such an arrangement, a cleaning head may be moved along the floor in such a way that the leading barrier member lifts so that it passes freely over dirt, debris and moisture on the floor, whereas the trailing barrier member, being nearer to the floor (for example in sliding contact with the floor) may sweep such dirt, debris and moisture on the floor. As such, any such dirt, debris and moisture on the floor may be retained within the footprint of the cleaning head and be sucked up from the floor.

The cleaning head may be so arranged that used cleaning liquid may be sucked from the floor via a channel forming part of, being adjacent to or otherwise associated with a barrier member. The barrier member may for example comprise a channel for sucking liquid from the floor. The channel may be provided between two walls, -9 -which may be arranged next to each other. The walls may each extend along the outer edge of the cleaner head.

The cleaning head may have a generally rectangular footprint having its shortest edge in the fore-aft direction in which a user might typically move the cleaner over the floor. In the case where there are multiple cleaning elements, the cleaning elements (for example the pads of the cleaning elements) may be arranged side by side along the longest edge of the rectangular footprint.

The floor cleaner may be associated with a separate dock for receiving the floor cleaner. Such a dock may comprise a receiving unit for receiving the floor cleaner. Such a dock may comprise a reservoir for containing a liquid, for example to enable the dock to replenish the cleaning liquid stored in the floor cleaner. Such a dock may comprise a reservoir for containing a liquid, for example to enable the dock to received waste water from the floor cleaner. Such a dock may comprise a reservoir for containing a liquid, for example to clean a part of the floor cleaner when docked.

The dock may comprise a charging unit, the charging unit arranged to charge a battery of a floor cleaner received in the receiving unit.

The cleaning head of the floor cleaner may be configured to be detachable from the rest of the floor cleaner. The cleaning head may therefore be provided separately. The cleaning head may comprise a mechanical connection to facilitate the mounting of the cleaning head to the rest of the floor cleaner. The cleaning head may comprise one or more fluid connectors to facilitate the flow of liquid to and/or from the cleaning head from and/or to the rest of the floor cleaner and/or the provision of suction to the floor region. The cleaning head may comprise a connector that when engaged with a corresponding part of the rest of the floor cleaner facilitates the transmission of motion from a motor housed in the body of the floor cleaner to one or more driven elements of the cleaning head. The cleaning head may comprise an electrical connection.

Each cleaning element may, at least in part, be configured to be detachable from the rest of the cleaning head. The cleaning element may therefore be provided separately. The cleaning element may comprise a mechanical connection to facilitate the mounting of the cleaning element to the cleaning head or a part of the cleaning element to the rest of the cleaning element. The cleaning element may, for example, include a detachable pad, brush assembly or the like. Such parts may be provided separately, for example as consumable parts having a limited useable lifetime -10 -compared to the floor cleaner itself Such parts may be reusable. Such parts may be removable to facilitate cleaning or washing of the parts separately from the rest of the cleaning element.

Figure 1 shows an external view of a floor cleaner 100 according to a first illustrated embodiment of the invention, wherein the floor cleaner comprises a cleaner body 106, a neck 102, a handle 104 and a cleaner head 112.

When in use, the bottom surface of the cleaner head 112 faces the floor surface to be cleaned. The cleaner head 112 is mounted at the base of the cleaner body 106 and is pivotally attached to allow for relative movement between the cleaner head and body 106. The neck 102 is in the form of a long and thin cylindrical shaft which extends upwardly from the cleaner body 106 to the handle 104. The handle 104 is an angled extension of the neck, and allows the user to operate the floor cleaner from a standing position. The cleaner body 106 and handle 104 move together as a relatively rigid body. The handle 104 comprises a user interface which enables the floor cleaner functions to be controlled by the user.

The cleaner body 106 comprises a housing which contains a vacuum suction element and two liquid tanks, one 108 for holding the cleaning fluid and the other 110 for containing waste liquid that has been removed from the floor via suction. In use, as the user moves the cleaner 100 over the floor to be cleaned, cleaning liquid from the tank 108 is applied to the floor. Moving parts (described later) of the cleaner head 112 agitate, scrub, or otherwise move over the floor, and in combination with the cleaning liquid clean the floor. Used and dirty liquid is then sucked up back into the waste water tank 110 of the cleaner body 106. The pivoting connection between the cleaner head 112 and the cleaner body 106, allows the user to move the cleaner back and forth over the floor, with the angle of the shaft of the neck 102 relative to the floor changing, while the cleaner head 1 1 2 remains parallel to the floor. The cleaner body 106 also comprises a battery (not shown in Figure 1) for powering various parts of the cleaner.

Figure 2 shows an external view of the floor cleaner 100 received into a dock 200, according to the same embodiment of the invention. The dock is arranged so that the cleaner head 112 of the floor cleaner 100 can be rested in the central cavity 202 of the dock 200 while the handle 102 can be propped up by a support arm 204, which allows the floor cleaner to stand upright in the dock. The dock 200 is connected into the mains power by a plug 208. The dock comprises a cleaning liquid tank for replenishing the cleaning liquid stored in the corresponding tank 108 of the floor cleaner, a waste tank for receiving waste water from the corresponding tank 110 of the floor cleaner, and a charging connector for (re-)charging the battery of the floor cleaner with power from the mains. The dock may be mobile and have its own battery unit.

Figure 3 shows a schematic diagram illustrating the function of the floor cleaner 100 of the first embodiment of the invention. The cleaner head comprises a main body 118, one or more cleaning elements 138, a front squeegee arrangement 114 and a rear squeegee arrangement 116. The main body 118 houses a motor 122 which drives the movement of the cleaning elements 138. The motor 122 is powered by a battery 132 housed in the cleaner body 106 (not shown separately in Figure 3). The squeegee arrangements 114, 116 are mounted on the main body 118 of the cleaner head via an attachment 124, which allows the squeegee arrangements to pivot up and down. Figure 3 shows the front squeegee arrangement 114 lifted off from the floor in front of the main body 118 and the rear squeegee arrangement 116 in contact with the floor behind the main body 118.

In use, the user may manually move the cleaner over the floor backwards and forwards in a fore-aft motion, represented by the double headed arrow 125. A connecting mechanism (not shown separately) between the handle 104 and the squeegee arrangements 114, 116 causes each of the two squeegee arrangements to be raised in turn dependent on the direction of movement of the floor cleaner. When the floor cleaner 100 is pushed forwards by the user (to the left in Figure 3), the front squeegee arrangement 114 (being the leading squeegee arrangement at that moment) moves to its raised position, thus allowing the cleaner head to move across the floor and over any dirt, liquid and the like on the floor in the region that was immediately in front of the cleaner head. At the same time the rear squeegee arrangement 116 (being the trailing squeegee arrangement at that moment) moves to its lowered position so that it is in contact with the floor, thus retaining any dirt, liquid and the like within the footprint of the cleaner head. When the floor cleaner 100 is pulled backwards by the user (to the right in Figure 3), the front squeegee arrangement 114 (now the trailing squeegee arrangement) moves to its lowered position and the rear squeegee arrangement 116 (now being the leading squeegee arrangement) moves to its raised position. Such a function allows any cleaning liquid or debris present on the floor in the regions around the cleaner head 112 to be swept over and subsequently -12 -collected by the cleaner head, and for the majority of any liquid added to the floor by the cleaner head to be retained within its footprint.

In this embodiment, each squeegee arrangement is formed by a pair of squeegees which are arranged either side of a suction opening 136. Waste liquid or debris present on the floor that is swept over by the cleaner head is collected by the trailing squeegee arrangement and is sucked through the suction opening 136 into the waste liquid tank 110 via a suction conduit 130. Suction is provided by a vacuum suction element 134 which is housed in the cleaner body 106 of the floor cleaner 100 and is powered by the battery 132.

The cleaning elements 138 are comprised of a cleaning element body 120 attached to each of which is a cleaning pad 126 which engages the floor during use. The motor 122 drives the motion of the cleaning elements 138 such that they are able to move relative to the main body 118. The movement and the shape of the cleaning pads, and variations thereof are described in more detail below in relation to Figure 4 and the subsequent Figures. It should be appreciated that while the drawing in Figure 3 shows schematically what appear to be at least two cleaning elements arranged fore and aft, it is possibly more likely that there will be either one cleaning element per cleaning head, or two cleaning elements per cleaning head arranged side-by-side. Other configurations are of course possible in other embodiments. Cleaning liquid from the cleaning liquid tank 108 is provided to the cleaning pads 126 via a conduit 128 that leads from the tank 108 to the cleaning element 138. The conduit is arranged so as to allow the cleaning liquid to flow at a controlled rate onto the cleaning pads 126, which then deliver the cleaning liquid to the floor. It will be appreciated that the geometry and arrangement of the tanks 108, 110 and conduits 128, 130 is not shown in Figure 3 and will depend on the position of the tanks in the body of the cleaner and the desired configuration of the outlets/inlets for liquid at the underside of the cleaning head. During use, it is possible for the cleaning pads to be kept wet/moist, rather than sodden, such that the floor is made wet, but without significant pools or liquid being deposited on the floor at any given time. The water to be fed to the floor may be warm and may be heated. The floor cleaner may include a water heater for such purposes, for example powered by the battery.

Figure 4 shows the underside of a cleaner head 112 in accordance with a first embodiment of the invention having a pair of rotating pads 126 for cleaning a floor. Cleaning liquid is fed to the floor via each pad 126 as it rotates. It will be seen that -13 -each pad 126 has three-fold rotational symmetry. Each pad has three lobes 129, each with a convexly shaped tip 131, which are positioned between concave regions 133 that are closer to the centre of the pad.

Each pad 126 is rotated about a fixed axis of rotation 158, positioned at the centre of the pad. Each pad's axis of rotation 158 is perpendicular to the plane of the pad. The pads 126 are rotated in opposite directions but at the same speed and in coordination with each other. The pads are shown in Figure 4 as being spaced apart from the body 118 of the cleaner head 112, the body 118 being shown schematically in Figure 4 as a box around the shapes of the pads. In other embodiments the pads 126 may extend up to or possibly slightly beyond the footprint of the body 118 of the cleaner head 112.

Figure 4 shows the left-hand pad 126L (as shown in Figure 4) as rotating clockwise (arrow 166L) and the right-hand pad 126R rotating anti-clockwise (arrow 166R). The motion of the pads from the position shown in Figure 4 is illustrated by Figures 5 to 13, which collectively show a rotation of each pad 126 about its axis 158 by 60 degrees. Ten degree rotations are shown between the positions shown in Figures 5 and 6, Figures 6 and 7, Figures 7 and 8, Figures 8 and 9. Five degree rotations are shown between the positions shown in Figures 9 and 10, Figures 10 and 11, Figures 11 and 12, and Figures 12 and 13. Figure 13 also shows for the sake of comparison the positions of the pads 126 in their position of Figure 5 (dashed outline 168). As the pads rotate the lobe 129 of one pad move into the concave space 133 between two lobes of the opposite pad.

The shape of each pad 126 as shown in Figures 4 to 13 is such that the radius of curvature of the shape of the lobes 129 is constant, and about four times greater than the smallest radius of curvature of the concave region 133, which also has a radius of curvature. The shape smoothly transitions from the concave region 133 to the lobe 129 such that the shape of each cleaning pad 126 as shown in the Figures is a smooth curve.

Having a smoothly curved shape and a concave space as shown in Figures 4 to 13 not only allows the lobes 129 of the other pad to sweep closer than might otherwise be the case, but the pads 126 also have no sharp corners which might otherwise trap dirt instead of allowing it to be sucked up with the cleaning liquid by the squeegee arrangements as the cleaning head 112 is moved back and forth by the user (see doubled headed arrow 170 in Figure 4). Figure 13 shows in light grey -14 -shading the area 172 covered (swept out) by the pads 126 as they complete a 120 degree rotation, and also in darker grey shading the overlapping area 174 covered (swept out) by each pad, showing there is no gap between the pads 126 not able to be covered when the cleaner is moved back and forth by the user. It will be seen that the lobes of each pad 126 enter the overlapping area 174, as the pad is moved through a full rotation. None of the concave regions enter the overlapping area 174 during a full rotation.

Cleaning liquid is fed via the centre of the rotating pad, and could be fed via a shaft about which the cleaning element 138 rotates. The liquid may additionally or alternatively be fed at other location around the planform of the cleaning element 138.

As the cleaning element 138 rotates the liquid may be dispersed over the body of the pad 126 and over and across the floor, at least within the footprint of the cleaning head 112, as a result of the centrifugal force on the liquid caused by the rotating pads 126. Liquid may thus be distributed more evenly and efficiently than if the liquid were applied directly to the floor.

Figures 14 to 18 show different shapes of cleaning element that could be utilised. The element 338 of Figure 14 has thinner lobes 329, provided with brushes 376 at the tips 331 of the lobes. The convexly shaped tip 331 of the lobes is sharper than in Figure 4, and defines a discernible vertex. The cleaning / scrubbing action could be located primarily in the region of the brushes 376. The brushes 376 could be located at other locations around or on the shape formed by the cleaning element 338 (and not be located solely at or adjacent to the vertices). The underside of the cleaning element 338 may still perform a cleaning action, and have cleaning liquid fed via the element. Thinner lobes may provide cleaning action with greater pressure on the floor than a corresponding thicker lobe.

The element 438 of the embodiment shown in Figure 15 has thicker lobes 429 than in Figure 14 and also has brushes 476 at the vertices. Thicker lobes may provide cleaning action over a wider area at any given moment.

The embodiments shown in Figure 16 to 18 each have 8-fold rotational symmetry. In Figure 16 the lobes 529 of the elements 538 have discernible vertices, albeit rounded vertices, at their ends furthest from the centre of the element. In Figure 17, the lobes 629 of the elements 638 are fatter at their ends furthest from the centre of the element and do not have vertices. Such a shape may enable the lobe of one element 638 to mesh better with the concave region of the other element. Such -15 -meshing could enable one element to be a master element which drives the other element, which would be a slave element. The shape the lobes 729 of the elements 738 of Figure 18 also allows for such meshing, but is formed from straight edges. The concave regions are thus formed of multiple straight edges in the element 738 of Figure 18.

In all embodiments shown in the Figures, but with specific reference to Figure 13, the two cleaning elements 138 of the cleaner head 112 are arranged to move such that the concave regions of one pad 126 is paired with a corresponding lobe of the adjacent pad, and vice versa, so that they move (whether or not in direct meshing engagement) such that as each lobe enters to its fullest extent, the overlapping area 174 between the pads 126, its corresponding concave region on the other pad is immediately opposite the lobe.

Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described. The floor cleaner may be one which operates independently of a mobile dock. The floor cleaner may be configured to operate with the need for a dock. The floor cleaner may be mains powered for example.

It will be appreciated that the use of rotating pads which have lobes, concave regions between lobes, and regions of overlap between adjacent pads when rotated as described in relation to the Figures does not necessarily require the cleaning liquid to be delivered to the floor via the cleaning pads, or delivered only via the pads. For instance, liquid could (additionally or alternatively) be delivered in the spaces within the footprint of the cleaner head not covered by the pads when they rotate. With reference to Figures 4 and 13, it will be seen that space is available for this purpose at the corners of the cleaner head 112 foot print and at the middle (left-right direction in the figures) of the footprint both above and below the area of overlap 174.

Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, -16 -convenient or the like are optional and do not limit the scope of the independent claims Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

Claims

-17 -Claims I. A floor cleaner for cleaning a floor, wherein the floor cleaner comprises a reservoir for storing cleaning liquid, and a cleaning head which is arranged to deliver cleaning liquid received from the reservoir to the floor, and to suck used cleaning liquid from the floor, the cleaning head including a plurality of driven cleaning elements, the cleaning elements each comprising a cleaning pad for engaging and cleaning the floor in combination with the delivered cleaning liquid, and wherein a first of the cleaning elements is arranged to be driven relative to the cleaning head with a component of rotational motion about an axis transverse to the floor as a second of the cleaning elements is arranged to be driven relative to the cleaning head with a component of rotational motion about an axis transverse to the floor in the opposite direction the area swept out by the rotation of a first cleaning pad of the first cleaning element overlaps with the area swept out by the rotation of a second cleaning pad of the second cleaning element, thus defining an overlap region between the first and second pads, the first cleaning pad includes multiple lobes each of which, in use, enter the overlap region, as the pad is rotated, the second cleaning pad includes multiple lobes each of which, in use, enter the overlap region, as the pad is rotated, the pads include multiple concave regions, each concave region being located between a pair of adjacent lobes of the pad, such that each concave region of one of the first and second pads is paired with a corresponding lobe of the other of the first and second pads, the concave region remaining outside of the overlap region as the corresponding paired lobe moves through the overlap region 2. A floor cleaner according to claim 1, wherein each lobe comprises a convexly shaped tip.3. A floor cleaner according to claim 2, wherein the smallest radius of curvature of the shape of one of the lobes is within 10% to 1000% of the smallest radius of curvature of the concave region paired with the lobe.-18 - 4. A floor cleaner according to claim 2 or claim 3, wherein the shape of the planform of each cleaning pad is a smooth curve.5. A floor cleaner according to claim 1, wherein each lobe comprises a pointed tip 6. A floor cleaner according to any preceding claim, wherein each pad comprises at least three lobes 7. A floor cleaner according to any preceding claim, wherein one cleaning elements is arranged to be a master cleaning element and another cleaning elements is arranged to be a slave cleaning element, wherein the master cleaning element is arranged to drive the slave cleaning element 8. A floor cleaner according to any preceding claim, wherein the cleaning head further comprises a barrier member for retaining cleaning liquid at least partly within a footprint of the cleaning head.9. A floor cleaner according to any preceding claim, wherein the cleaner head comprises a first barrier member on one side of the foot print of the cleaner head and a second barrier member on an opposite side of the foot print of the cleaner head.A floor cleaner according to any preceding claim, wherein the floor cleaner arranged to deliver cleaning liquid received from the reservoir to the floor via the cleaning pads of the cleaning elements.11. A floor cleaner according to any claim 10, wherein each of the cleaning pads comprises an open cell foam material, which allows liquid to drain therethrough.12. A floor cleaner according to any preceding claim, wherein each of the cleaning pads comprises an absorbent material.-19 - 13 A floor cleaner according to any preceding claim, wherein the cleaner head comprises multiple suction inlets arranged to be adjacent to the floor when the cleaner is in use, the suction inlets being spaced apart from the cleaning elements and being provided to suck used cleaning liquid from the floor.14 A floor cleaner according to any preceding claim further including a waste tank for receiving used cleaning liquid sucked from the floor by the cleaning head.15. A cleaning head for a floor cleaner according to any preceding claim.16. A cleaning pad for a floor cleaner according to any of claims 1 to 14.