Field of the Invention

The present invention relates to a cleaner head for an appliance, and to an appliance comprising such a cleaner head.

Background of the Invention

Appliances for cleaning or treating surfaces may comprise a cleaner head that is in contact with the surface to be cleaned or treated in use. Some appliances utilise liquids, such as water, to clean or treat a surface. Such liquids may be utilised alongside a roller, mop, wipe, or other component for applying a wiping force to the surface.

Summary of the Invention

According to a first aspect of the present invention there is provided a cleaner head for an appliance, the cleaner head comprising: a housing; and a liquid collection tank for collecting liquid from a surface to be cleaned, the liquid collection tank releasably connected to a portion of the housing; wherein the liquid collection tank comprises a main body, and a cover releasably connected to the main body, and the cover at least partially defines an inlet of the liquid collection tank.

As the liquid collection tank is releasably connected to a portion of the housing, and is located within the housing, a user may be required to disconnect the liquid collection tank from the portion of the housing in order to empty the liquid collection tank. As the cover is releasably connected to the main body, and the cover at least partially defines the inlet of the liquid collection tank, the user may be able to remove the cover, which is likely to encounter dirty liquid in use, such that the cover and the main body of the liquid collection tank may be thoroughly cleaned. This may facilitate cleaning compared to, for example, an arrangement where a cover remains attached to the main body during emptying and cleaning of the liquid collection tank.

The inlet may extend across at least 75% of a width of the liquid collection tank. This may facilitate collection of liquid across a large proportion of the width of the liquid collection tank, which may inhibit liquid from accidentally being transferred back to the surface to be cleaned in use. The inlet may extend across at least 80% or at least 85% of a width of the liquid collection tank. The inlet may be located symmetrically about a center line of the liquid collection tank, for example a center line that bisects the width of the liquid collection tank.

The inlet may have the form of an elongate slot at least partially defined by the cover. This may facilitate collection of liquid in comparison to, for example, a plurality of smaller apertures, where liquid may take a greater amount of time to pass through the smaller apertures.

The cover may be releasably connected to the main body via an interference fit. This may provide a secure yet relatively easily releasable connection.

The cover may comprise a handle spaced from the inlet, the handle facing outwardly from an upper surface of the cover. This may facilitate disconnection of the cover from the main body, and may enable a user to grasp the cover at a region remote from the inlet. This may be more hygienic than, for example, an arrangement where a user is required to grasp the inlet to remove the cover.

The main body may have a first height, and the inlet may be located at second height lower than the first height. This may accommodate for liquid pooling on the cover whilst inhibiting liquid from being accidentally transferred back to the surface to be cleaned in use. The first height may be a maximal height of the main body.

The cover may comprise an outer periphery and an inner periphery, the inner periphery may at least partly define the inlet, and the cover may comprise a sloped surface between the outer periphery and the inner periphery. This may guide liquid from the outer periphery toward the inlet.

The liquid collection tank may extend across at least 90% of the width of the housing, for example across substantially the entirety of a width of the internal volume of the housing. This may facilitate displacement of liquid into the liquid collection tank across substantially the entirety of the width of the cleaner head in use. The liquid collection tank may extend across at least 90% of the width of the housing between a pair of opposing side walls of the housing.

The cleaner head may comprise a roller for contacting the surface to be cleaned, the roller configured to cause displacement of liquid from the surface to be cleaned into the inlet of the liquid collection tank in use. Such a roller may facilitate collection of liquid in the liquid collection tank, and may also apply a wiping force to the surface to be cleaned in use. The cleaner head may comprise a mangle configured to contact the roller such that liquid carried by the roller is displaced into the inlet of the liquid collection tank in use. This may facilitate removal of dirty liquid from the roller and into the liquid collection tank.

The roller may extend across at least 90% of the width of the housing, for example across substantially the entirety of a width of the internal volume of the housing. This may ensure that the roller provides a relatively large surface area with which to contact the surface to be cleaned for a given width of cleaner head. The housing may comprise a pair of opposing side walls, and the roller may extend across at least 90% of the width of the housing between the pair of opposing side walls.

The liquid collection tank may comprise a surface contact member for contacting a surface to be cleaned, and the roller my be configured to direct liquid toward the surface contact member in use. This may ensure that any liquid is directed toward the liquid collection tank, rather than being passed underneath the liquid collection tank.

The housing may comprise a first housing portion and a second housing portion, the first and second housing portions may be releasably connected to one another, and the first housing portion may comprise the liquid collection tank. Accordingly, the liquid collection tank may be releasably connected to the second housing portion. In some examples, the first housing portion may be entirely the liquid collection tank, and in other examples, the first housing portion may further include other components of the cleaner head. The liquid collection tank may thus be removed from the housing and accessible to a user once the first and second housing portions are disconnected from one another.

The first and second housing portions may be slidably connected to one another along an axis parallel to a rotational axis of a roller connected to the housing. This may enable the first and second housing portions to be disconnected from one another without needing to remove further components, such as the roller, from the cleaner head.

The inlet of the liquid collection tank may face in a direction toward an upper surface of the housing when the cleaner head is located on a surface to be cleaned in use. This may inhibit liquid from spilling outwardly from the liquid collection tank in use, for example in comparison to an arrangement where the inlet faces in a direction toward a side, front, rear, or lower surface of the housing when the cleaner head is located on the surface to be cleaned in use. The cleaner head may comprise a liquid distribution tank for storing liquid to be distributed to a surface to be cleaned. This may facilitate cleaning of the surface to be cleaned in use.

The liquid distribution tank may be fixedly connected to the liquid collection tank. As the liquid collection tank is fixedly connected to the liquid distribution tank, emptying of the liquid collection tank and filling of the liquid distribution tank takes place when both the liquid collection tank and the liquid distribution tank are present. The liquid distribution tank may be indirectly connected to the liquid collection tank, for example via one or more intermediate components such as the first housing portion.

Collectively the liquid distribution tank and the liquid collection tank may form part of a tank assembly, and the first housing portion may comprise the tank assembly. This may ensure that both the liquid distribution tank and the liquid collection tank are removable at the same time, which may encourage a user to both empty the liquid collection tank and refill the liquid distribution tank at the same time. This may aid with inhibiting overfilling of the liquid collection tank which could otherwise occur if the liquid collection tank were not emptied when the liquid distribution tank were refilled.

The liquid distribution tank may comprise an inlet, the liquid collection tank may comprise an outlet, the outlet of the liquid collection tank may face in a first direction along the housing of the cleaner head, and the inlet of the liquid distribution tank may face in a second direction along the housing of the cleaner head different to the first direction along the housing of the cleaner head. By providing the liquid collection tank with an outlet that faces in a different direction to the inlet of the liquid distribution tank, crosscontamination between tanks may be inhibited during emptying and/or filling.

The housing may comprise an internal volume within which the liquid distribution tank and the liquid collection tank are located, the first direction may be a first direction within the internal volume of the housing, and the second direction may be a second direction within the internal volume of the housing.

The second direction may be substantially orthogonal to the first direction. This may be particularly effective at inhibiting cross-contamination between tanks during emptying and/or filling.

The inlet of the liquid distribution tank may be located within an internal volume of the housing. As the inlet is located within an internal volume of the housing, the inlet may be inaccessible to a user of the cleaner head in use, and hence a user may be required to remove the liquid distribution tank from the internal volume of the housing to access the inlet. This may help to inhibit, for example, excessive liquid contact with electronic components of the cleaner head and/or unintended liquid contact with, for example immersion of, the cleaner head, when compared to an arrangement in which the inlet is accessible on an external surface of the cleaner head in use. Locating the inlet within the internal volume of the housing may ensure that the inlet is not easily accessible in use of the cleaner head, and may inhibit impact with the inlet which could otherwise cause leakage of liquid from the liquid distribution tank.

The inlet may comprise an inlet for enabling filling and/or refilling of the liquid distribution tank. The liquid distribution tank may be removable from the internal volume of the housing, for example by at least partial disassembly of the housing such that the internal volume is no longer defined.

The cleaner head may comprise a drive component for driving distribution of liquid from the liquid distribution tank. Use of a drive component may provide greater control of distribution of liquid from the liquid distribution tank than, for example, a passive distribution arrangement.

The inlet may be closed by a closure having a valve member that fluidically connects an interior of the liquid distribution tank to the drive component. Combining the inlet closure with the valve member may effectively provide a single point of entry and exit for liquid into and out of the liquid distribution tank, which may provide a reduced risk of leakage in comparison to an arrangement where multiple inlet and outlet points are distributed across the liquid distribution tank. The closure may be removable to enable filling of the liquid distribution tank.

The liquid collection tank may comprise an internal volume greater than an internal volume of the liquid distribution tank. This may enable the liquid collection tank to hold more liquid than that contained within the liquid distribution tank, which may, for example, enable the cleaner head to accommodate additional surface liquid in use.

The internal volume of the liquid collection tank may be at least 10% greater than the internal volume of the liquid distribution tank, for example at least 15% greater than the internal volume of the liquid distribution tank. This may enable sufficient capacity to accommodate liquid from a surface to be cleaned. The internal volume of the liquid collection tank may be around 20% greater than the internal volume of the liquid distribution tank. This may be a reasonable compromise between accommodating additional liquid from a surface to be cleaned and the overall volume of the liquid collection tank.

The liquid distribution tank may extend partially across a width of the housing, the drive component may extend partially across the width of the housing, and the liquid distribution tank and the drive component may be adjacent to one another across the width of the housing. As the liquid distribution tank and the drive component may be adjacent to one another across the width of the housing, dimensions of the housing other than the width, for example such as the height and/or the depth of the housing, may be minimised in comparison to an arrangement where the drive component and the liquid distribution tank are offset from one another across the width of the housing. Minimising a height of the housing may be desirable to maintain a relatively low height profile of the cleanerhead, thereby enabling the cleaner head to be placed underneath objects such as furniture in use.

The liquid distribution tank and the drive component may be aligned with one another across the depth and/or height of the housing, for example such that the drive component is located within a projected footprint of the liquid distribution tank across the depth and/or height of the cleaner head, or vice versa. The width of the housing may comprise a width of an internal volume of the housing.

The second housing portion may comprise the drive component. This may enable the drive component to be kept separate from the liquid distribution tank and the liquid collection tank, for example during refilling of the liquid distribution tank and emptying of the liquid collection tank. This may help to inhibit, for example, excessive liquid contact with the drive component and/or unintended liquid contact with, for example immersion of, the drive component.

Disconnection of the first and second housing portions may break a fluidic connection between the liquid distribution tank and the drive component. This may enable the liquid distribution tank and the drive component to be kept separate from one another during refilling of the liquid distribution tank. This may help to inhibit, for example, excessive liquid contact with the drive component and/or unintended liquid contact with, for example immersion of, the drive component.

The drive component may comprise a pump for pumping liquid from the liquid distribution tank. This may facilitate distribution of liquid from the liquid distribution tank. The roller may be located at a first end of the housing, and the liquid distribution tank and the drive component may be located at a second opposite end of the housing. This may provide a balanced weight distribution for the cleaner head.

The liquid collection tank may be located intermediate the roller and the liquid distribution tank. Locating the liquid collection tank between the roller and the liquid distribution tank may, in comparison to an arrangement where the liquid collection tank is located above the liquid distribution tank or vice versa, provide a relatively low height profile for the cleaner head. This may facilitate placing of the cleaner head underneath objects, such as furniture, in use.

The liquid collection tank may extend across the width of the cleaner head to a greater extent than the liquid distribution tank. This may, for example, facilitate collection of liquid from a surface to be cleaned in use, for example by allowing liquid to be displaced into the liquid collection tank across a greater extent of the width of the cleaner head than if the liquid collection tank were limited to the extent of the liquid distribution tank.

According to a second aspect of the present invention there is provided an appliance comprising a cleaner head according to the first aspect of the present invention.

The appliance may comprise a main unit, and the cleaner head may be releasably attachable to the main unit. This may enable the functionality of the cleaner head to be selectively provided for the appliance, for example enabling the cleaner head to be swapped for a further cleaner head of different form and/or functionality.

The main unit may comprise a power supply for supplying electrical power to the cleaner head. This may reduce the need for a separate power supply to be provided in the cleaner head, which may reduce size and/or weight and/or cost of the cleaner head.

According to a third aspect of the present invention there is provided a cleaner head for an appliance, the cleaner head comprising: a roller comprising a material for contacting a surface to be cleaned; and a liquid delivery assembly for delivering liquid to the material; wherein the liquid delivery assembly is configured to deliver liquid to the material so that the material is between 10% and 30% saturated with liquid.

The material of the roller being between 10% and 30% saturated with liquid has been found to provide good cleaning performance. Specifically, this saturation has been found to provide useful wetness of the surface to be cleaned. For example, if the saturation is too low, then not enough liquid may be applied to the surface to be cleaned via the roller and hence cleaning performance may be sub-optimal. On the other hand, if the saturation is too high, too much liquid may be applied to the surface to be cleaned via the roller, and the surface may accordingly become unacceptably wet. It has been found that a liquid saturation of the material of the roller between 10% and 30% provides a sufficient amount of liquid to the surface to be cleaned via the roller to allow good cleaning performance but without causing the surface to become unacceptably wet. Efficient cleaning may therefore be provided. In examples, the liquid may be water. In examples, the saturation may be the saturation of the material in steady state operation of the cleaner head.

The liquid delivery assembly may be configured to deliver liquid to the material so that the material is between 25% and 28% saturated with liquid. The material of the roller being between 25% and 28% saturated with liquid has been found to provide particularly good cleaning performance. Specifically, this saturation has been found to provide particularly useful wetness of the surface to be cleaned and may be particularly desired. Specifically, it has been found that a liquid saturation of the material of the roller between 25% and 28% provides a sufficient amount of liquid to the surface to be cleaned via the roller to allow particularly good cleaning performance but without causing the surface to become unacceptably wet. In examples, a liquid saturation of 28% may be particularly preferred.

In examples, the liquid delivery assembly may be configured to deliver liquid to the material at a rate of between 25 and 35 millilitres per minute, for example at a rate of 30 millilitres per minute. The surface area of the material may be between 800 and 900 square centimetres, for example around 820 square centimetres. For example, the radius of the roller at the material may be around 58 mm, and the length of the roller may be around 226 mm. The material may be microfibre having a density of between 46500 and 85250 fibres per square centimetre. These parameters may help provide that a liquid saturation of the material between 10% and 30%, specifically between 25% and 28%. Moreover, this may be provided while using a relatively low rate of liquid delivery. This may provide for an efficient use of the liquid. For example, where liquid is supplied from a liquid distribution tank, the low rate of water usage may extend the operation time until the liquid distribution tank needs to be refilled. Alternatively, or additionally, using microfibre of this density and having this liquid saturation may provide for particularly effective cleaning performance. In examples, the roller may have a length of between 225 and 227 millimetres, for example around 226 millimetres. In examples, the roller may have a radius of around 60 millimetres. It will be appreciated that the radius of the roller may vary slightly depending on, for example, whether the material is wet or dry. For example, when the material is wet, the roller may have an overall radius of 58 millimetres, and when the material is dry, the roller may have an overall radius of 62 millimetres, for example.

The cleaner head may comprise a roller drive configured to drive rotation of the roller while the liquid delivery assembly delivers liquid to the material. The roller drive may be configured to drive rotation of the roller at a rate between 500 and 1200 revolutions per minute, for example between 900 and 1000 revolutions per minute. Driving rotation of the roller may help allow the liquid to be relatively evenly spread around the circumference of the material of the roller, and hence for a relatively even liquid saturation level of the material. Alternatively, or additionally, this may reduce the time taken for the liquid to be provided relatively evenly across an entire surface of the material of the roller. Rotation of the roller may alternatively or additionally provide that parts of the material that have lost liquid can be replenished with liquid by the liquid delivery assembly. For example, parts of the roller may lose liquid due to contact of the material with a relatively dry surface to be cleaned, or for example because of removal of liquid from the material by a mangle in order to remove dirty liquid and/or debris from the material after coming into contact with a surface to be cleaned. Rotating the roller allows the liquid to be replenished by the liquid delivery assembly, for example to maintain a desired liquid saturation of between 10% and 30%, specifically between 25% and 28%. Rotating the roller at between 500 and 1200 revolutions per minute, for example 900 to 1000 revolutions per minute, may help liquid to be delivered evenly to the material, for example even when relatively short pulses of liquid delivery are used. Alternatively or additionally, rotating the roller at between 500 and 1200 revolutions per minute, for example 900 to 1000 revolutions per minute, may help provide particularly good cleaning performance.

The cleaner head may comprise a mangle configured to remove liquid, for example excess liquid, and/or debris from the material. The mangle may span the material in a direction parallel to the axis of the roller. The mangle may have a thickness of around 2 millimetres. The mangle may penetrate into the material a distance of between 2 and 3 millimetres, for example 2.5 millimetres. That is, the mangle may extend beyond an outer diameter of the material of the roller in use, by a distance of between 2 and 3 millimetres, for example 2.5 millimetres. The thickness (e.g. the pile thickness) of the material of the roller may be around 5 millimetres. Accordingly, in examples, the mangle may penetrate the material, or otherwise extend beyond an outer diameter of the material of the roller in use, between 40% and 60% of the thickness of the material, for example 50% of the thickness of the material. The mangle may be provided by a strip or bar that contacts the material, for example penetrates into the material, such as into the microfibres of a microfibre material. The mangle may help remove dirty liquid and/or debris from the material, for example which has been generated by the cleaning of the surface or picked up from the surface. For example, the rotation of the roller may urge the material against the mangle and cause liquid and/or debris to become separated therefrom. This may be transferred, for example, into a collection tank, which the cleaner head may also comprise. Alternatively or additionally, the mangle, in cooperation with the liquid delivery assembly, may help maintain a desired liquid saturation of the material over a period of time and/or during different uses. For example, the mangle may be configured so as to remove liquid from the material when the saturation goes beyond a desired level (e.g. 28%). For example, this may be achieved by the mangle penetrating into the material, or otherwise extending beyond an outer diameter of the material of the roller in use, by a distance of between 2 and 3 millimetres. For example, in cases where the cleaner head is applied to clean a wet surface causing the material to increase above 28% liquid saturation, the mangle may act to remove the excess liquid to reduce the saturation to desired levels (e.g. 28%) again. Similarly, in cases where excess liquid is delivered by the liquid delivery assembly that might otherwise take the liquid saturation of the material beyond desired levels, the mangle may act to remove the excess liquid to maintain the saturation at desired levels (e.g. 28%). Accordingly, the mangle may allow for a relatively simple liquid delivery assembly to be provided (for example one which need not necessarily actively monitor the liquid saturation of the material), but whilst still allowing for liquid saturation of the material in a desired range (e.g. 25% to 28%) to be maintained.

The liquid delivery assembly may comprise a drive component for driving distribution of liquid to the material. For example, the drive component may comprise a liquid pump. Using a drive component may allow for improved control over the liquid delivery, and hence allow for a more consistent operation and cleaning effectiveness of the cleaner head. For example, this may be as compared to not using a drive component and instead, for example, relying solely on gravity to urge liquid towards the material.

The drive component may be configured to drive the distribution of liquid to the material in pulses. For example, the drive component may comprise a pump configured to operate in a pulsed or cyclical manner. For example, the pump may be configured to be on (thereby driving the distribution of liquid to the material) for a first duration and then off (thereby not driving the distribution of liquid to the material) for a second duration. The pump may be configured or otherwise controlled to repeat this sequence, thereby driving the distribution of liquid to the material in pulses. As another example, the drive component may comprise a pump and a valve for controlling the passage of liquid from the pump. For example, the pump may operate continuously, and the valve may be configured or otherwise controlled to open and close in a pulsed or cyclical manner. For example, the valve may be configured to be open (thereby driving the distribution of liquid to the material) for a first duration and then off (thereby not driving the distribution of liquid to the material) for a second duration. The valve may be configured or otherwise controlled to repeat this sequence, thereby driving the distribution of liquid to the material in pulses. In any case, driving the liquid distribution in pulses may help allow for improved control over the delivery of liquid to the material of the roller. For example, driving the liquid distribution in pulses may allow for a given overall liquid delivery rate to be achieved (e.g. averaged over the pulses), but while allowing the pressure at which the liquid is distributed (e.g. during each pulse) to be relatively high. This may be as compared, for example, to driving the liquid distribution continuously. This may, in turn, allow for several benefits. For example, distributing the liquid at relatively high pressure may allow for liquid to be relatively evenly distributed along the roller. For example, the liquid delivery assembly may comprise a reservoir to which liquid is driven by the drive component via a reservoir inlet (e.g. a single inlet), and the reservoir may comprise a plurality of outlets (e.g. eight outlets or holes) via which liquid is delivered to the material. Driving the liquid at relatively high pressure to the reservoir may allow for the reservoir to fill relatively evenly, and hence for each of the outlets to deliver a similar amount of liquid as one another. This may, in turn, help improve the evenness with which the material of the roller is wetted with liquid, which in turn may help improve overall cleaning performance. Further, driving the liquid at relatively high pressure to the reservoir may allow that the pressure is high enough in the reservoir so that liquid is expelled from the outlets. This may provide improved control of the liquid delivery, for example as compared to simply allowing the liquid to drip from the outlets. As another example, driving the liquid at relatively high pressure may allow for clearing of parts of the liquid delivery assembly which might otherwise become clogged up with dirt or other debris. For example, the outlets of the reservoir may be configured to be relatively small (e.g. 1 millimetre in diameter) in order to provide suitable water delivery. Driving the liquid at relatively high pressure may allow for unclogging of such outlets, should that occur during cleaning.

The drive component may be configured to drive the distribution of liquid for a first duration to generate each pulse; and consecutive pulses may be separated by a second duration in which the drive component does not drive the distribution of liquid. This may provide for simple control over the liquid delivery rate, should that be desired. For example, the liquid delivery rate can be controlled by controlling the length of the first duration relative to the second duration (that is, the duty cycle). This may be simpler and more cost effective than, for example, providing a drive component that is capable of variable continuous liquid driving rates. In examples where the pulses are provided by controlling the pump to be on for the first duration and off for the second duration, this may provide that the pump is only operating some of the time during cleaning. This may help reduce power consumption and/or prolong the life of the pump. For each pulse, the first duration may be between 2% and 9% of the second duration. For example, the first duration may be around 8% of the second duration, or around 4% of the second duration. For example, the first duration may be 0.25 seconds. The second duration may be between around 3 seconds and around 10 seconds. For example, the second duration may be around 3 seconds or around 6 seconds. This may help provide a suitable water delivery rate, for example to provide, in turn, a desired saturation level of the material of the roller (e.g. between 25% and 28%). Moreover, this may provide that the drive component is mostly off, which may help save energy and/or prolong the operating life of the drive component.

The cleaner head may comprise a roller drive configured to drive rotation of the roller, and the first duration last for at least one revolution of the roller. For example, the first duration may last for between 2 and 5 revolutions of the roller, for example between around 3.8 and 4.2 revolutions of the roller, for example around 4 revolutions of the roller. For example, the first duration may be 0.25 seconds, and the roller may be driven to rotate at between 500 and 1200 revolutions per minute, which would result in the first duration lasting for between around 2 to 5 revolutions. As another example, the first duration may be 0.25 seconds, and the roller may be driven to rotate at between 900 and 1000 revolutions per minute, which would result in the first duration lasting for between around 3.8 to 4.2 revolutions of the roller. Having the first duration last for at least one revolution of the roller may help ensure that liquid is delivered evenly around the entire circumference of the roller. This may in turn help improve the evenness with which the material is wetted and/or may help improve the speed with which an even wetting of the material is achieved. The first duration lasting for between 2 and 5 revolutions of the roller, for example between around 3.8 and 4.2 revolutions of the roller, for example around 4 revolutions of the roller may provide an optimum condition between evenness of liquid distribution, the rate of rotation of the roller, and the duty cycle of the drive component.

The liquid delivery assembly may comprise a reservoir to which liquid is driven by the drive component via a reservoir inlet, and the reservoir may comprise a plurality of outlets via which liquid is delivered to the material. For example, the plurality of outlets may be arranged along a direction parallel to the rotational axis of the roller. The reservoir and outlets may provide a simple and space efficient means by which to distribute the liquid across the material of the roller.

The liquid delivery assembly may comprise a distribution surface for distributing liquid onto the material, the distribution surface extending in a direction parallel to the rotational axis of the roller, the distribution surface being provided with liquid from the outlets of the reservoir. The distribution surface may reduce spitting of liquid from the material when the liquid is delivered to the material. For example, in some cases, spraying liquid directly onto the material from the outlets may cause the liquid to impact the rotating roller material at relatively high speeds, which may in turn cause some of the liquid to bounce off the material rather than being absorbed by it. However, by providing a distribution surface that is provided with liquid from the outlets and which distributes the liquid onto the material, the liquid can be slowed down before contacting the material. This may in turn reduce spitting and hence improve the consistency with which liquid is absorbed into the material.

The cleaner head may further comprise a liquid distribution tank for storing liquid to be distributed to the material by the drive component. Providing a liquid distribution tank in the cleaner head allow the cleaner head to be portable. As another example, this may allow for the liquid to be stored close to the liquid delivery assembly, which may help minimise piping required to provide liquid to the material of the roller.

According to a fourth aspect of the present invention, there is provided an appliance comprising a cleaner head according to the third aspect of the invention.

The appliance may comprise a main unit, and the cleaner head may be releasably attachable to the main unit. This may enable the functionality of the cleaner head to be selectively provided for the appliance, for example enabling the cleaner head to be swapped for a further cleaner head of different form and/or functionality.

The main unit may comprise a power supply for supplying electrical power to the drive component and/or the roller drive. This may reduce the need for a separate power supply to be provided in the cleaner head, which may reduce size and/or weight and/or cost of the cleaner head.

According to a fifth aspect of the present invention, there is provided a cleaner head for an appliance, the cleaner head comprising: a roller for contacting a surface to be cleaned; a roller drive configured to drive rotation of the roller; and a mangle configured to contact the roller to remove liquid from the roller rotating in use; wherein the roller drive is configured to, in use, drive rotation of the roller such that the speed of the roller at the mangle is between 3 and 8 meters per second.

The speed of the roller at the mangle being between 3 and 8 meters per second has been found to provide controlled, reliable and/or precise liquid removal from the roller. For example, the cleaner head may comprise a liquid collection tank for collecting the liquid removed by the mangle. The speed of the roller at the mangle being between 3 and 8 meters per second may help provide that the liquid is provided to the liquid collection tank (or another desired location) as opposed to other, undesired locations. For example, at higher speeds, it has been found that liquid has a tendency to separate or spit off from the roller even without contacting the mangle. This can cause liquid, for example dirty liquid, to be provided in undesirable locations, such as back onto the surface to be cleaned, as opposed to into the liquid collection tank (or other desired location). As another example, at lower speeds, it has been found that liquid removed from the roller by the mangle has a tendency to drip or flow back down the roller surface (and ultimately back onto the surface to be cleaned) as opposed to being projected into the liquid collection tank (or other desired location at the mangle). Accordingly, the speed of the roller at the mangle is between 3 and 8 meters per second, this may allow that the roller is travelling fast enough that liquid removed by the mangle is travelling fast enough to be projected into a liquid collection tank (or other desired location at the mangle) without dripping or flowing back down the roller surface, but not so fast that the liquid would separate or spit off from the roller before hitting the mangle. Accordingly, a controlled, reliable and/or precise liquid removal from the roller may be provided. The speed may be the steady state operational speed of the roller at the mangle. This may allow for the above benefits in use of the wet cleaner head, for example during cleaning.

The roller drive may be configured to drive rotation of the roller at between 500 and 1200 revolutions per minute. This may provide the abovementioned range of roller speeds at the mangle, for example for rollers of a suitable size for domestic use. For example, the radius of the roller may be between 58 and 62 millimetres, for example around 60 millimetres. This may help ensure that the cleaner head can have a relatively low profile, for example to allow the cleaner head to fit under furniture, for example. It will be appreciated that the radius of the roller may vary slightly depending on whether material of the roller for contacting the surface to be cleaned is wet or dry. In examples, the radius of the roller may be 58 millimetres when the material is wet, and 62 millimetres when the material is dry. As above, the rate of rotation of the roller may be the steady state operational rotation speed of the roller.

The roller drive may be configured to, in use, drive rotation of the roller such that the speed (e.g. steady state operational speed) of the roller at the mangle is between 5 and 7 meters per second. This has been found to provide particularly controlled, reliable and/or precise liquid removal from the roller. For example, operation in this range may ensure that liquid (e.g. dirty liquid or a liquid spill to be cleaned) does not drip back down the surface of the roller from the mangle or spit off from the roller even without contact with the mangle, but rather is removed from the roller at the mangle so as to be provided to a liquid collection tank (or other desired location at the mangle). The roller drive may be configured to drive rotation of the roller at between 900 and 1000 revolutions per minute. This may provide the abovementioned range of roller speeds at the mangle, for example for rollers with a radius of between 58 and 62 millimetres. This size may be suited for domestic use. As above, the rate of rotation of the roller may be the steady state operational rotation speed of the roller.

The roller may comprise a material for contacting the surface to be cleaned, and the mangle may penetrate into the material for removing liquid from the material of the roller rotating in use. For example, the roller may comprise a cylindrical base surface and the material may be provided on the base surface. The mangle may span the material in a direction parallel to the rotational axis of the roller. The mangle may have a thickness of around 2 millimetres. The mangle may penetrate into the material a distance of between 2 and 3 millimetres, for example 2.5 millimetres. That is, the mangle may extend beyond an outer diameter of the material of the roller in use, by a distance of between 2 and 3 millimetres, for example 2.5 millimetres. The thickness of the material may be around 5 millimetres. Accordingly, in examples, the mangle may penetrate the material between 40% and 60% of the thickness of the material, for example 50% of the thickness of the material. The material may be microfibre having a density of between 46500 and 85250 fibres per square centimetre. These parameters may provide for liquid removal from the roller material at a reasonable rate, while also helping to ensure that the load on the roller drive (such as a motor) when rotating the roller material against the mangle is kept relatively small. This may, in turn, allow for a relatively small motor to be used and/or to reduce the degree to which the motor heats up.

The mangle may be provided by a strip or bar that contacts the material, for example penetrates into the material, such as into the microfibres of a microfibre material. The mangle may help remove dirty liquid and/or debris from the material, for example which has been generated by the cleaning of the surface or picked up from the surface. For example, the rotation of the roller may urge the material against the mangle and cause liquid to become separated therefrom. This may be transferred, for example, into a liquid collection tank, which the cleaner head may also comprise.

The mangle may be positioned on the roller at an angular displacement of between 30 and 60 degrees, about the rotational axis of the roller, from a plane passing through the rotational axis of the roller and parallel to the surface to be cleaned when the cleaner head is located on the surface to be cleaned in use. These angular displacements may correspond to positions between 10 o’clock and 11 o’clock if the end of the roller were to be viewed as a clockface (or equally between 1 and 2 o’clock, depending on the side from which the roller is viewed). For example, the angular displacement may be 30 degrees (10 or 2 o’clock). These positions may allow for efficient transfer of the liquid from the mangle to a desired location, such as a liquid collection tank of the cleaner head. For example, where the mangle is located around these positions, the liquid that is removed by contact with the mangle may be projected both upwards and outwards away from the mangle. This projection may accordingly allow the liquid to travel (e.g. following a curved trajectory) towards a desired location (such as a liquid collection tank inlet). This may reduce the need to provide additional energy to the liquid in order for it to travel to the liquid collection tank. Moreover, the projection upwards and outwards may allow for the liquid collection tank inlet to be located relatively high relative to the mangle, which may in turn allow for the liquid collection tank to have a relatively large volume. This may, in turn, allow for an increase in the time between emptying of the liquid collection tank. As a comparative example, were the mangle to be positioned at an angular displacement nearer 90 degrees (12 o’clock), the extracted liquid may not be projected sufficiently outwards away from the mangle, and hence may have a significant tendency to flow back down the mangle onto the roller, which is undesirable. On the other hand, were the mangle to be positioned at an angular displacement nearer 0 degrees (9 or 3 o’clock), the overall height of the liquid collection tank inlet would need to be lower in order to allow the liquid to flow into the liquid collection tank e.g. under gravity (which would restrict the size of the collection tank), or the liquid would need to be pumped to the liquid collection tank, which would consume energy. In examples, the mangle may be positioned to the rear of the roller, that is, inwardly of the cleaner head relative to the roller, for example between the roller and the liquid collection tank. The mangle may be positioned above the plane passing through the rotational axis of the roller and parallel to the surface to be cleaned in use. The roller may be driven to rotate so that the roller impinges the mangle from below in use. This may allow that the removed liquid is projected upwards and outwards, for example underneath a curved portion of the cleaner head and into the liquid collection tank. The speed of the mangle at the roller is sufficient that the removed water travels away from the roller towards the collection tank, rather than dripping back down the surface of the roller.

The cleaner head may comprise a liquid collection tank for collecting the liquid removed from the roller by the mangle in use. This may provide that the removed liquid (e.g. dirty liquid) and/or debris can be collected in the cleaner head itself. This may improve portability of the cleaner head. As another example, this may allow for the removed liquid to be collected relatively close to the mangle, which may help reduce or negate pumping or piping to transport the liquid to liquid the collection tank. The liquid collection tank may have an inlet through which liquid removed by the mangle enters the liquid collection tank, and, relative to the surface to be cleaned when the cleaner head is located on the surface to be cleaned in use, the height of the mangle may be between 3 and 5 millimetres more than the height of the inlet of the liquid collection tank. This may allow that the liquid removed by the mangle can be projected towards and flow into the inlet of the collection tank, but whilst still ensuring the height of the liquid collection tank can be relatively large. This may, in turn, allow for the volume of the liquid collection tank to be relatively large, which may increase the operation time before the liquid collection tank is full.

The cleaner head may comprise, adjacent to the mangle, a curved portion configured to guide the liquid removed from the roller by the mangle along a curved path towards the liquid collection tank. For example, the curved portion may be concave from the perspective of the surface to be cleaned when the cleaner head is located on the surface to be cleaned in use. This curved portion may help guide the liquid towards the collection tank without removing significant energy from the liquid projected by contact with the mangle. For example, the curve of the curved portion may approximate the curve of the projection of the liquid upwards and outwards from the mangle. Reducing the energy taken away from the projected liquid while guiding the projected liquid to the inlet of the liquid collection tank may allow for the inlet to be positioned relatively far away from the mangle and/or relatively high. This may, in turn, allow for the liquid collection tank to have a relatively large volume, which may increase the operation time between emptying the liquid collection tank.

According to a sixth aspect of the invention, there is provided an appliance comprising the cleaner head according to the fifth aspect.

The appliance may comprise a main unit, and the cleaner head may be releasably attachable to the main unit. This may enable the functionality of the cleaner head to be selectively provided for the appliance, for example enabling the cleaner head to be swapped for a further cleaner head of different form and/or functionality.

The main unit may comprise a power supply for supplying electrical power to the roller drive. This may reduce the need for a separate power supply to be provided in the cleaner head, which may reduce size and/or weight and/or cost of the cleaner head.

Optional features of aspects of the present invention may be equally applied to other aspects of the present invention, where appropriate. Brief Description of the Drawings

Figure 1 is a perspective view of a cleaner head;

Figure 2 is an exploded perspective view of the cleaner head of Figure 1 , showing first and second housing portions;

Figure 3 is a perspective view of the first housing portion of Figure 2 in isolation;

Figure 4 is a bottom plan view of the first housing portion of Figure 3;

Figure 5 is an upper plan view of the first housing portion of Figure 3;

Figure 6A is a perspective view illustrating a removable cover of a liquid collection tank of the first housing portion of Figure 3, and Figure 6B is a cross-sectional view of a squeegee of the first housing portion of Figure 3;

Figure 7 is a perspective view of the second housing portion of Figure 2 in isolation;

Figure 8 is a perspective view of the second housing portion of Figure 7 with a wall section removed;

Figure 9 is a right side view of the second housing portion of Figure 7;

Figure 10 is a schematic view of the cleaner head of Figure 1 with an upper wall and a side wall of its housing removed;

Figure 11 is a schematic cross-sectional view taken along a central depth line of the cleaner head of Figure 1 ;

Figure 12 is an enlarged view of the circled region denoted A in Figure 11; and

Figure 13 is a schematic illustration of an appliance comprising the cleaner head of Figure 1.

Detailed Description of the Invention

A cleaner head 10 is illustrated in Figures 1 to 2. The cleaner head 10 comprises a housing 12, a roller 14, and an attachment mechanism 16. The roller 14 is rotatably connected to the housing 12 such that it rotates about a rotational axis R (see Figure 2) that is substantially parallel to a width direction W of the housing 12. The housing 12 comprises a first housing portion 18 and a second housing portion 20 releasably connected to each other.

The first housing portion 18 is illustrated in Figures 3 to 6, and comprises a right side wall 22, a tank assembly 24, a mounting member 26, a catch mechanism 28, and a projection in the form of a guide strip 30. The right side wall 22 is generally elongate in form, and extends generally in a depth direction D of the cleaner head 10. The tank assembly 24 and the mounting member 26 are each fixedly connected to the right side wall 22 (allowing the mounting member 26 to be fixedly connected to the tank assembly 24). The tank assembly 24 and the mounting member 26 extend from the right side wall 22 such that the tank assembly 24 and the mounting member 26 are located within the housing 12 when the cleaner head 10 is assembled. The catch mechanism 28 and the guide strip 30 are generally centrally located along the right side wall 22.

The mounting member 26 is located at a front end 32 of the right side wall 22, with the tank assembly 24 located rearwardly of the mounting member 26. The front end 32 of the right side wall 22 is generally shaped to correspond to the curvature of the roller 14, and has a region of reduced radius such that the roller 14 is partially exposed at the front of the housing 12 when the cleaner head 10 is assembled and the roller 14 contacts the surface to be cleaned.

The tank assembly 24 comprises a liquid distribution tank 34 for storing liquid to be distributed to a surface to be cleaned and a liquid collection tank 36 for collecting liquid from the surface to be cleaned. The liquid collection tank 36 and the liquid distribution tank 34 are fixedly connected to one another. The liquid distribution tank 34 is hollow in form and has a curved rear wall 37, a flat base wall 38, a wheel 40, an inlet 42, and a closure 44. The wheel 40 is disposed in the flat base wall 38. The inlet 42 is covered and closed by the closure 44 in Figures 4 and 5, and has the form of an aperture defined by a neck with an external screw thread that cooperates with an internal screw thread of the closure 44. The inlet 42 is located on the liquid distribution tank 34 such that the inlet 42 is located within an interior volume of the housing 12 when the cleaner head 10 is assembled. The inlet 42 faces in a first direction W along the housing 12 of the cleaner head 10. This first direction is a direction toward a sidewall of the housing 12 when the cleaner head 10 is located on a surface to be cleaned in use. The closure 44 has the form of a cap that covers the inlet 42, and is removable from the inlet 42 via twisting. The closure 44 comprises a valve member 46 that enables fluidic communication between an interior of the liquid distribution tank 34 and a drive component comprising a pump 84 (see Figure 8).

The liquid distribution tank 34 has an internal volume of around 300ml. The liquid distribution tank 34 extends for substantially the full height direction H of the cleaner head 10, but only extends partially (for a little over 50%) across a width direction W of the housing 12 of the cleaner head 10. The liquid distribution tank 34 is located at a rear end 48 of the right side wall 22, and forms part of a rear surface of the cleaner head 10 when the cleaner head 10 is assembled.

The liquid collection tank 36 comprises a main tank body 50, an upper plate 52, a removable cover 54 releasably connected to the main tank body 50 via an interference fit, The liquid collection tank 36 further comprises a front wall 56 and a surface contact member in the form of a squeegee 58. The squeegee 58 and removable cover 54 are entirely removable from the main tank body 50. The liquid collection tank 36 is located generally centrally along the right side wall 22, such that the liquid collection tank 36 is located between the liquid distribution tank 34 and the mounting member 26. A bottom surface of the liquid collection tank 36 and a bottom surface of the liquid distribution tank 34 are substantially aligned.

The main tank body 50 is generally cuboidal and hollow in form, and extends across substantially the entirety of the width direction W of the cleaner head 10 when the cleaner head 10 is assembled. An upper region of the main tank body 50 is open such that the hollow interior of the main tank body 50 is accessible via the upper region. The main tank body 50 has an internal volume of around 360ml, giving the liquid collection tank 36 an internal volume 20% greater than the internal volume of the liquid distribution tank 34.

The upper plate 52 is generally solid and planar in form, and is fixedly connected to a rear section of a periphery of the upper region of the main tank body 50 such that the upper plate 52 overlies around 50% of the upper region of the main tank body 50. The removable cover 54 is selectively locatable underneath the upper plate 52 such that the removable cover 54 overlies the upper region of the main tank body 50.

Referring to Figure 6A, the removable cover 54 is generally rectangularly shaped in plan view, and has an outer periphery 60, an inner periphery 62, a sloped surface 64, and a handle in the form of a pull-tab 66, and mounting wings 67. The sloped surface 64 slopes from the outer periphery 60 to the inner periphery 62 such that the inner periphery 62 is located a lower height relative to the outer periphery 60 when the removable cover 54 is located on the main tank body 50. The pull tab 66 is located on a front periphery of the removable cover 54 and is facing outwardly from an upper surface of the cover 54 (in particular, it is upstanding from the sloped surface 64). The inner periphery 62 defines an elongate slot that acts as a combined inlet/outlet 65 of the liquid collection tank 36. The combined inlet/outlet 65 may be located symmetrically about a center line of the liquid collection tank 36. Due to the sloped surface 64, the combined inlet/ outlet 65 is located at a height lower than a height of the main tank body 50. The combined inlet/outlet 65 faces in a second direction H along the housing 12 of the cleaner head 10, where the second direction H is different to the first direction W in which the inlet 42 of the liquid distribution tank 34 faces. As shown in Figure 1 , the second direction H is substantially orthogonal to the first direction W and to the rotational axis R, and is a direction toward an upper surface of the housing 12 when the cleaner head 10 is located on a surface to be cleaned in use. The mounting wings 67 extend from sides of the outer periphery 60 near a front region of the outer periphery 60, and are shaped and dimensioned to be received between the upper plate 52 and the front wall 56 of the liquid collection tank 36. The pull tab 66 is spaced from the combined inlet/outlet 65 by virtue of its location on the sloped surface 64.

The front wall 56 is arcuate in form, and is shaped to generally correspond to the curvature of the roller 14. A lower region of the front wall 56 is shaped and spaced from the main tank body 50 to define a channel within which the squeegee 58 is received. The channel is open at one end to enable the squeegee 58 to slide into and out of the channel.

The squeegee 58 is formed of a resiliently deformable material, and is shaped such that the squeegee 58 is an extension of the front wall 56 when located within the channel. When located within the channel, the squeegee 58 extends from the front wall 56 such that a surface of the squeegee 58 and a surface of the front wall 56 form a continuous surface. As shown in Figure 6B, a rear portion of the squeegee 58 includes an elongate element 581 extending from a top surface of the squeegee 58. The elongate element 581 includes a first elongate recess 582a and a second elongate recess 582b. Referring to Figure 11 , the arcuate front wall 56 ends with a first elongate protrusion 562a. A second elongate protrusion 562b extends from the bottom of the main tank body 50, and is arranged vertically below the first elongate protrusion 562a. To locate the squeegee 58 within the channel, the squeegee 58 is slid relative to the main tank body 50, and the first 562a and second 562b elongate protrusions are received within the first 582a and second 582b elongate recesses respectively. The squeegee 58 extends to a position slightly lower than a lower surface of the main tank body 50 when located within the channel. A vertical gap G (see Figure 3) between the lower surface of the main tank body 50 and the surface to be cleaned is thus formed when the cleaner head is in use. As the roller 14 rotates, the rotational energy from the roller 14 helps to scoop the liquid (from the surface to be cleaned) up along the arcuate front wall 56. The vertical gap G is dimensioned so that it is small enough to prevent dirty liquid from the surface being cleaned to pass beyond the squeegee toward the rear of the cleaner head 10, and large enough to prevent scratching of the surface by the main tank body 50. A height (along the direction H in Figure 1) of this vertical gap G may range from about 0.2mm to 1 ,5mm.

As previously noted, the mounting member 26 is located at the front end 32 of the right side wall 22. The mounting member 26 is releasably connected to the roller 14 and rotatably mounts the roller 14 within the housing 12. The mounting member 26 is shaped and dimensioned to be received within, and engage with, the roller 14. The mounting member 26 is fixedly connected to the right side wall 22, yet comprises a bearing assembly (not shown) to enable rotation of the roller 14 when connected to the mounting member 26. Further details of the mounting member 26 will be apparent to a person skilled in the art, and so will not be described here for sake of brevity.

The catch mechanism 28 is located substantially centrally along the right side wall 22, above the liquid distribution tank 34. The catch mechanism 28 comprises a depressible button 70 and a hook 72 movable in response to movement of the depressible button 70. The hook 72 is releasably engageable with a corresponding latch (not shown) formed on an underside of an upper wall 74 (see Figure 7) of the second housing portion 20.

The guide strip 30 is elongate in form and extends in the width direction W to a similar extent as that of the liquid collection tank 36. The guide strip 30 is spaced vertically apart from the upper plate 52, and is shaped and dimensioned to be received within a guide channel 94 of the second housing portion 20. The guide strip 30 has a generally T- shaped cross-sectional shape.

The second housing portion 20 is illustrated in Figures 7 to 12. The second housing portion 20 comprises an upper wall 74, a left side wall 76, control circuitry 78, a drive mechanism in the form of a roller drive 80, a pump compartment 82, a pump 84, a liquid tube 86, an intermediate plate 87, a reservoir 88, a distribution surface 90, a mangle 92, and a guide channel 94. The roller 14 is rotatably connected to the second housing portion 20. A front end of the upper wall 74 is shaped to correspond to the curvature of the roller 14, and a planar portion of the upper wall 74 comprises a notch 96 shaped and dimensioned to receive the depressible button 70 of the catch mechanism 28.

The left side wall 76 is generally elongate in form, and extends in the depth direction D of the cleaner head 10. The outer surface of the left side wall 76 is the same shape as that of the right side wall 22. The left side wall 76 is hollow in form, and defines a compartment 98 within which the control circuitry 78 is housed. The compartment 98 is sealed from any regions within the housing 12 that contain liquid in use. An inner surface of the left side wall 76 comprises a locating feature in the form of a locating ridge 77 that generally corresponds to a side surface of the liquid collection tank 36.

The control circuitry 78 comprises appropriate control circuitry for driving the roller drive 80 and the pump 84. Further details of how the control circuitry 78 drives the roller drive 80 and the pump 84 will be provided hereafter. The control circuitry 78 also comprises a delay component, specifically a delay circuit, the functionality of which will be discussed hereafter.

The roller drive 80 is located at, and fixedly connected to, a front end 100 of the left side wall 76 at a similar position to which the mounting member 26 is connected to the right side wall 22 of the first housing portion 18. The roller drive 80 comprises an appropriate torque generator, such as a motor, for generating a torque to drive rotation of the roller 14. The roller drive 80 is shaped and dimensioned to fit within an interior of the roller 14, such that the roller drive 80 is located internally of the roller 14 with the roller 14 and the roller drive 80 concentric when the cleaner head 10 is assembled. The roller drive 80 is controlled by the control circuitry 78 to operate at a rate of rotation of around 900- 1000rpm in a steady state. Steady state operational speeds in the region of 500- 1200rpm are also envisaged.

The pump compartment 82 is substantially hollow in form, and is shaped and dimensioned to receive the pump 84 therein. The pump compartment 82 is further shaped and dimensioned to correspond to a projected footprint of the liquid distribution tank 34. The pump compartment 82 is located at a rear end 102 of the left side wall 76, and extends partially in the width direction W of the cleaner head 10. The pump compartment 82 has an aperture (not shown) which enables the pump 84 to connect to the valve member 46 of the closure 44 of the liquid distribution tank 34.

The pump 84 is any appropriate pump for driving liquid from the liquid distribution tank 34 to the reservoir 88, as will be discussed in more detail hereafter. The pump 84 is controlled by the control circuitry 78 to operate in a pulsed or cyclical manner, with the pump 84 controlled to be on for a first duration, to be off for a second duration, and so on. In other words, the pump 84 is on (i.e. drives the distribution of liquid) for the first duration to generate each pulse and consecutive pulses are separated by the second duration in which the drive component does not drive the distribution of liquid. The first duration lasts for at least one revolution of the roller 14. The first duration may be 0.25 seconds and the second duration may be 6 seconds, which equates to the first duration being around 4% of the second duration. With a roller speed of between around 900rpm and 10OOrpm, the first duration of 0.25 seconds equates to the pump 84 being controlled to be on for between around 3.8 and 4.2 revolutions of the roller 14. With a roller speed of between around 500rpm and 1200rpm, the first duration of 0.25 seconds equates to the pump 84 being controlled to be on for between around 2 and 5 revolutions of the roller 14. In other examples, the pump 84 may be controlled to be off for a duration of between around 3 and 10 seconds. In still other examples, the first duration may be between around 2% and 9% of the second duration. In yet still other examples, there may be a valve for controlling the passage of liquid from the pump 84. For example, the pump 84 may operate continuously, and the valve may be configured or otherwise controlled to open and close in a pulsed or cyclical manner.

Referring to Figure 10, the liquid tube 86 extends from the pump 84 to the reservoir 88 along the intermediate plate 87. The intermediate plate 87 is fixedly connected to the left side wall 76 at a region between the front 100 and rear 102 ends of the left side wall 76, and is vertically spaced apart from the upper wall 74. An upper surface of the intermediate plate 87 comprises a dividing wall 104 and a lower surface of the intermediate plate 87 comprises the guide channel 94 (see Figure 9). The dividing wall 104 extends across the width of the intermediate plate 87, and, together with the upper wall 74 defines a guide region 106 and a reservoir region 108.

The guide region 106 is a hollow cavity that acts to guide the liquid tube 86 from the pump 84 to the reservoir 88, and to guide electrical looming from the attachment mechanism 16 to the control circuitry 78 within the compartment 98. The liquid tube 86 extends through a gap in the dividing wall 104 to bridge the guide region 106 and the reservoir region 108.

The guide channel 94 extends across the lower surface of the intermediate plate 87 in the width direction W of the cleaner head 10. The guide channel 94 is shaped and dimensioned to receive the guide strip 30 of the first housing portion 18. An end of the guide channel 94 opposite to the left side wall 76 is open such that the guide strip 30 can be slidably received within the guide channel 94. Referring to Figure 12, the reservoir 88 is at least partly formed by the second housing portion 20 and is defined by the upper surface of the intermediate plate 87 in the reservoir region 108, reservoir side walls 110, and a reservoir cover 91 located between lower surface of the upper wall 74 of the second housing portion 20 and the upper ends of the reservoir walls 110. The reservoir 88 is generally cuboidal in form and is elongate along an axis parallel to a rotational axis of the roller 14. A seal 112 (which may include silicon) is located about a periphery of the reservoir side walls 110, in particular, between the side walls 10, the reservoir cover 91 and the intermediate plate 87. The reservoir side walls 110 are shaped such that the reservoir 88 extends across the width direction W of the cleaner head 10, and has a width in the direction W of around 202mm. The reservoir 88 extends for around 90% of a length of the roller 14 (where the length of the roller 14 extends along the W direction shown in Figure 1), although the reservoir 88 extending for at least 80% of the length of the roller 14 is also envisaged. The reservoir 88 has an interior volume of around 1444mm ³ . An interior volume of up to around 1571 mm ³ is also envisaged.

The reservoir 88 has a reservoir inlet 114 and eight reservoir outlets 116, although between 6 to 10 reservoir outlets are also envisaged. The reservoir inlet 114 comprises a circular aperture formed centrally along a rear one of the reservoir side walls 110, in a reservoir inlet surface 115 which is a side surface of the reservoir 88 facing the liquid distribution tank 34. The reservoir inlet 114 is in fluid communication with the liquid tube 86 and receives liquid from the liquid distribution tank 34. The reservoir inlet 114 has a radius in the region of 1.25mm, although radii in the region of 1.00mm to 1.50mm are also envisaged.

The reservoir outlets 116 are spaced substantially evenly along a length of the reservoir 88 along an axis parallel to the rotational axis of the roller 14. Further, they are offset from the reservoir inlet 114 along the axis parallel to the rotational axis of the roller 14. The reservoir outlets 116 comprise generally circular apertures formed in a reservoir outlet surface 117 of the intermediate plate 87 in the reservoir region 108, which is a base surface of the reservoir 88. Each reservoir outlet 116 has a radius of around 1.00mm, and the reservoir outlets 116 are spaced by around 28.00mm along the width direction W of the cleaner head 10. The reservoir outlets 116 cover a length extending to around 90% of a length of the roller 14, although the reservoir outlets 116 covering a length of at least 80% of the length of the roller 14 is also envisaged. The cross-sectional area of the reservoir inlet 114 is larger (e.g. less than 3 times larger) than the cross- sectional area of each reservoir outlet 116. In one example, the reservoir inlet 114 has a radius of around 1.25 times the radius of an individual reservoir outlet 116, whilst the reservoir inlet 114 has a radius of around 0.16 times the combined radius of the reservoir outlets 116. A ratio of a total combined cross-sectional area of the reservoir outlets 116 to a cross-sectional area of the reservoir inlet 114, and a ratio of an interior volume of the reservoir 88 to a total combined cross-sectional area of the reservoir outlets 116 are such that in use, liquid exits the reservoir 88 substantially uniformly from the plurality of reservoir outlets 116. The combined cross-sectional area of the reservoir outlets 116 is around 5 times the cross-sectional area of the reservoir inlet 114. The interior volume of the reservoir 88 is around 1444 times the radius of each individual reservoir outlet 116, and is around 181 times the total combined cross-sectional area of the reservoir outlets 116. Such a configuration of the reservoir 88, in combination with the pulsed delivery cycle of the pump 84 mentioned previously, provides a water flow rate of around 30ml/min in the reservoir 88, alongside a pressure of around 13.5kPa to 14.5kPa in the reservoir 88. Radii of between 0.80mm and 1 ,20mm are also envisaged for the reservoir outlets 116, as is a spacing of around 25.00mm to 30.00mm between each reservoir outlet 116. Thus, a combined cross-sectional area of the reservoir outlets 116 of between around 2.5 and 10 times the cross-sectional area of the reservoir inlet 114, an interior volume of the reservoir 88 of between 150 to 400 times the combined cross-sectional area of the reservoir outlets 116, an interior volume of the reservoir 88 of between 1300 to 2800 times the individual cross-sectional area of each of the reservoir outlets 116, and an interior volume of the reservoir 88 of between 900 to 1900 times the cross-sectional area of reservoir inlet 114 are also envisaged. Variations in size of the reservoir inlet 114 and the reservoir outlets 116 can lead to water flow rates in the reservoir 88 of between 25ml/min and 35ml/min. In other words, liquid is delivered to the pile 122 of the roller 14 at a rate of between 25ml/min and 35ml/min.

The distribution surface 90 is defined by a protrusion 118 of the second housing portion 20, where the protrusion 118 extends from the lower surface of the intermediate plate 87 underneath the reservoir outlets 116. The protrusion 118 forms a distribution structure comprising the distribution surface 90 for distributing liquid onto the pile 122 of the roller 14. The distribution surface 90 is below the reservoir outlet surface 117 (but nonoverlapped by this surface 117) when the cleaner head 10 is located on the surface to be cleaned, in use. The distribution surface 90 is substantially planar in form (in other words, substantially flat), and extends substantially parallel to the planar portion of the upper wall 74 (and substantially parallel to the reservoir outlet surface 117 and the surface to be cleaned when the cleaner head is located on this surface, in use). The distribution surface 90 is thus elongate along an axis parallel to a rotational axis of the roller 14 (R, illustrated in Figure 2, which is parallel to the width direction W of the cleaner head 10), with a substantially uniform distance between the edge of the distribution surface 90 and the roller 14 (indicated in Figure 12 using the reference numeral g). The distance g is taken in a direction perpendicular to the rotational axis of the roller 14 (R, shown in Figure 2) and along the depth direction D of the cleaner head (shown in Figure 1), and is very small in the example of Figure 12. However, it is envisaged that the distance between the edge of the distribution surface 90 and the roller 14 may be larger in other cases.

The distribution surface 90 is located around 1.6mm below each reservoir outlet 116 (indicated as a height h in Figure 12, which is parallel to a height direction H of the cleaner head 10 as shown in Figure 1 and represents a distance between a plane including the reservoir outlet surface 117 and a plane including the distribution surface 90). The distribution surface 90s has a depth d in the depth direction D of the cleaner head (in other words, a depth d along a short axis of the distribution surface 90) of around 4.1 mm. Distances of around 1.5mm to 1.7mm between the distribution surface 90 and the reservoir outlet surface 117(corresponding to heights h as shown in Figure 12), are also envisaged, as are depths d in the region of 4.0mm to 4.3mm. Although not illustrated, dividers are positioned between adjacent ones of the reservoir outlets 116 along the distribution surface 90. The reservoir outlets 116 are positioned between first and second separating members 119a, 119b that separate the distribution surface 90 from the reservoir outlet surface 117. The dividers are the same as the separating members 119a, 119b but positioned between two adjacent reservoir outlets 116 rather than at each end of the reservoir outlet surface 117.

The protrusion 118 also defines a collection surface 123 which is directly beneath the reservoir outlets 116, and is thus overlapped by the reservoir outlet surface 117. The collection surface 123 has a concave curved form, and extends substantially parallel to the planar portion of the upper wall 74. At least a portion of the collection surface 123 is angled with respect to the distribution surface. Liquid deposited on the collection surface 123 by the reservoir outlets 116 is urged by the collection surface 123 towards the distribution surface 90. The distribution surface 90 adjoins the collection surface 123 and is offset from the reservoir outlets 116 horizontally.

The mangle 92 is an elongate protrusion affixed to an underside of the intermediate plate 87, where a part of the mangle 92 is positioned below the distribution surface 90. A thickness TM of the mangle may be around 2mm. The protrusion 118, which in this case forms a distribution structure comprising the distribution surface 90, abuts the mangle 92. The distribution structure transfers liquid to the roller 14 substantially without transfer of the liquid to the mangle 92. The mangle 92 extends forwardly of the distribution surface 90, with a vertical distance v of around 3.4mm between the edge of the distribution surface 90 (facing the roller 14) and the mangle 92. The vertical distance v is in a direction perpendicular to the rotational axis R of the roller 14 and is parallel to a height direction H of the cleaner head 10. Vertical distances v of around between 3.0mm and 4.00mm are also envisaged. As shown in Figure 12, a portion of the roller 14 is located between the edge of the distribution surface 90 and the mangle 92. The mangle 92 projects at an acute angle 0 of approximately 30 to 60 degrees (see Figure 11) with respect to the distribution surface 90 and relative to an axis of rotation of the roller 14 from a plane passing through the rotational axis of the roller 14 and parallel to the surface to be cleaned when the cleaner head 10 is located on the surface to be cleaned in use. The mangle 92 is dimensioned to extend around 2.5mm into the roller 14 (with such extension labelled E in Figure 12), as will be discussed in more detail hereafter. The mangle 92 is thus at an acute angle 0 (in this case of between approximately 30 to 60 degrees) relative to the distribution surface 90. Penetration depths E of between 2mm and 3mm are also envisaged.

The roller 14 comprises a core 120 and a material for contacting a surface to be cleaned where the material is in the form of a pile 122. The core 120 is generally cylindrical (with a cylindrical base surface) and hollow in form. An interior of the core 120 is provided with fixing mechanisms for releasably fixing the roller 14 to the roller drive 80 and the mounting mechanism 26. Details of such fixing mechanisms are not pertinent to the present invention, and so will not be described here for sake of clarity. A diameter of the core 120 is sufficiently large that the roller drive 80 can be received within the core 120. The pile 122 is a microfibre pile with a density of between 46,500 and 85,250 fibres/cm ² . The pile 122 has a thickness T of around 5mm. The roller 14 as a whole has a radius of around 62mm when dry, and around 58mm when wet. The roller 14 has a length of around 226mm, although lengths in the region of 225mm and 227mm are also envisaged. In other words, a surface area of the pile 122 is between 800 and 900 square centimetres.

As previously noted, the cleaner head 10 comprises an attachment mechanism 16. The attachment mechanism 16 comprises a lower portion 124 and an upper portion 126. The lower portion 124 is hingedly mounted to a central region of the upper wall 74 of the second housing portion 20, such that the lower portion 124 can move in a plane defined by the depth D and height H directions of the cleaner head 10. The upper portion 126 is hingedly mounted to the lower portion 124 to enable the upper portion 126 to move relative to the lower portion 124 in a plane defined by the width W and height H directions of the cleaner head 10.

The upper portion 126 comprises a connection formation 128, and looming, which isn’t shown for sake of clarity. The connection formation 128 comprises a catch for releasably connecting to either a wand 204 or a main unit 202 of an appliance 200. Details of the catch are not pertinent to the present invention, and will not be described here for sake of brevity. The connection formation 128 is tubular in form and solid, such that there is no airflow path therethrough. The looming provides an electrical connection between the main unit 202 of the appliance 200 and the cleaner head 10.

The cleaner head is shown in an assembled configuration in Figure 1 and in a disassembled configuration in Figure 2.

To assemble the cleaner head 10, the roller 14 is connected to the roller drive 80, and the first 18 and second 20 housing portions are moved toward one another via a sliding motion along the width direction W of the cleaner head 10. The guide strip 30 is received in the guide channel 94 to guide the relative sliding motion. As a result of the sliding motion, the first 18 and second 20 housing portions are brought together and the hook 72 of the catch mechanism 28 engages the latch of the upper wall 74 of the second housing portion 20 to secure the first 18 and second 20 housing portions in place relative to one another. Thus, the first 18 and second 20 housing portions are slidably connected to one another along an axis parallel to the rotational axis R of the roller 14.

Bringing together the first 18 and second 20 housing portions moves the mounting member 26 into contact with the roller 14, such that the roller 14 is rotatably connected to the housing 12 by each of the mounting member 26 and the roller drive 80. The locating ridge 77 locates the tank assembly 24 relative to the second housing portion 20. In particular, the locating ridge 77 defines a recess for receiving a portion (side wall) of the liquid collection tank 36. The valve member 46 of the closure 44 of the liquid distribution tank 34 is brought into contact with the pump 84 such that a fluidic connection is made between the liquid distribution tank 34 and the pump 84. When the first 18 and second 20 housing portions are assembled together, the roller 14 is located at a first end of the housing 12 and the liquid distribution tank 34 is located at a second end of the housing 12 (the first and second ends being opposite to each other along the depth direction D of the housing 12). The liquid collection tank 36 is located between the liquid distribution tank 34 and the roller 14 in the depth direction D of the housing 12. Further, both the inlet 42 of the liquid distribution tank 34 and the combined inlet/outlet 65 of the liquid collection tank 36 are located within an internal volume of the housing 12. Additionally, the liquid distribution tank 34 and the pump 84 are adjacent to one another across the width of the housing 12. In other words, each of the liquid distribution tank 34 and the pump 84 extends partially across the width of the housing 12. In the assembled configuration, the roller 14 extends along the width of the cleaner head 10 between the right side wall 22 and the left side wall 76 of the respective first 18 and second 20 housing portions, at the front of the cleaner head 10. The reservoir 88 overlies a rear portion of the roller 14. The mangle 92 extends into the pile 122 of the roller 14. The liquid collection tank 36 is located rearwardly of the roller 14, with the front wall 56 spaced slightly from the roller 14 to enable rotation of the roller 14 within the housing 12. The combined inlet/outlet 65 of the liquid collection tank 36 faces toward the upper wall 74 of the cleaner head 10. The mangle 92 is positioned between 3 and 5mm higher (with such a distance labelled m in Figure 11) than the combined inlet/outlet 65 of the liquid collection tank 36. The liquid collection tank 36 extends across the width direction W of the cleaner head 10 to a similar extent to that of the roller 14 between the right side wall 22 and the left side wall 76 of the respective first 18 and second 20 housing portions. The liquid collection tank 36 and the roller 14 may each extend across at least 90% of the width of the housing 12 (i.e. dimension of the housing 12 along the direction W between the opposing side walls 22, 76). The combined inlet/outlet 65 may extend across at least 75% of a width of the liquid collection tank 36.

The liquid distribution tank 34 is located rearwardly of the liquid collection tank 36. The liquid collection tank 36 extends across the width in the direction W (between the opposing side walls 22, 76) of the housing 12 to a greater extent than the liquid distribution tank 34. The pump compartment 82, and hence the pump 84, are located adjacent to the liquid distribution tank 34 across the width W of the cleaner head 10. The attachment mechanism 16 is located centrally on the upper wall 74 such that the attachment mechanism 16 overlies the liquid collection tank 36, and is connected to the upper wall 74 at a point between the roller 14 and the liquid distribution tank 34.

To disassemble the cleaner head 10, a user depresses the depressible button 70 to remove the hook 72 of the catch mechanism 28 from engagement with the latch of the upper wall 74 of the second housing portion 20. At the same time, the user applies a force to separate the first 18 and second 20 housing portions by relative sliding of the first 18 and second 20 housing portions. Sliding motion of the first 18 and second 20 housing portions is constrained by movement of the guide strip 30 along the guide channel 94 to be in a direction parallel to a rotational axis R of the roller 14.

Since the tank assembly 24 is arranged within the first housing portion 18, the tank assembly 24 is releasably connected to the second housing portion 20 when the first 18 and second 20 housing portions are assembled. As the user slides the first 18 and second 20 housing portions away from one another along a connection axis (parallel to the axis of rotation R of the roller 14), the tank assembly 24 is moved along the connection axis and is disconnected from the second housing portion 20. Disconnection of the first 18 and second 20 housing portions breaks the fluidic connection between the liquid distribution tank 34 and the pump 84. Similarly, the connection between the mounting member 26 and the roller 14 is broken, with the mounting member 26 being removed from within an end of the core 120 of the roller 14. The user can continue to separate the first 18 and second 20 housing portions until the guide strip 30 leaves the guide channel 94, and the first 18 and second 20 housing portions are discrete, separated components.

In such a manner, the tank assembly 24, i.e. the liquid distribution tank 34 and the liquid collection tank 36, is removable from the second housing portion 20 by sliding the tank assembly 24 along the width direction W of the cleaner head 10. The tank assembly 24 is then located separately from electronic components of the cleaner head 10, and the liquid collection tank 36 can be emptied, and the liquid distribution tank 34 can be refilled. The removable cover 54 can be removed from the liquid collection tank 36 to aid with emptying.

Similarly, the roller 14 may then be removed from the second housing portion 20 by sliding the roller 14 along its axis of rotation to separate the roller 14 from the roller drive 80. The roller 14 can then be cleaned by a user.

When desired, the user can reassemble the cleaner head 10 in the manner previously described.

T o use the cleaner head 10, the attachment mechanism 16 is used to connect the cleaner head 10 to an appliance 200, as illustrated schematically in Figure 13.

The appliance 200 has a main unit 202, and a wand 204 releasably connected to the main unit 202. The cleaner head 10 can be connected to either of the main unit 202, or to the wand 204, depending on a user’s preference. The main unit 202 houses a power supply in the form of a battery 206, an airflow generator 208, and a control module 210. Power can be provided from the battery 206 to the airflow generator 208, and to the cleaner head 10 via a terminal (not shown) of the main unit 202, under control of the control module 210. Further details of the main unit 202 are not pertinent to the present invention, and will not be discussed here for sake of brevity.

The control module 210 determines whether the cleaner head 10 is attached to the main unit 202 based on a current drawn from the terminal in response to a voltage applied to the terminal. When the cleaner head 10 is attached to the main unit 202, either directly or via the wand 204, and a user actuates the main unit 202 by pressing a button or trigger or the like (i.e. sends a trigger signal indicating that the appliance is to be operated), the control module 210 of the main unit 202 causes a first voltage pulse to be sent to the cleaner head 10 via the terminal. As previously noted, the control circuitry 78 comprises a delay circuit. The delay circuit is configured to delay the draw of current by the cleaner head 10 from the terminal in response to the applied voltage. Specific details of the delay circuit are not important, and will be immediately apparent to a person skilled in the art. For example, an RC delay circuit may be utilised. This delay circuit means that, in response to the first voltage pulse, the control module 210 of the main unit 202 does not detect a current profile of the cleaner head 10 within a first time period of around 65-95ps post commencement of the first voltage pulse. The control module 210 of the main unit 202 then causes a second voltage pulse to be sent to the cleaner head 10 via the terminal. The control module 210 of the cleaner head 10 then detects a current profile within a second time period of say 300-350ps post commencement of the second voltage pulse.

Such a current profile, for example no current detected in the first time window and current detected in the second time window, may be distinctive compared to that provided by other cleaner heads, for example other cleaner heads without a delay circuit where a current profile is detected within the first time period by the control module 210 of the main unit 202. Thus the control module 210 can determine when the cleaner head 10 is attached to the main unit 202 based on the delay with which (or the particular one of a plurality of time periods) current is drawn from the terminal in response to the applied voltage. The control module 210 can also determine that a cleaner head other than cleaner head 10 is attached to the main unit 202 based on current being drawn from the terminal in response to the applied voltage in a different particular one of the plurality of time periods. If no current is drawn from the terminal in response to the applied voltage in any of the plurality of time periods, then it can be determined that no cleaner head is attached to the main unit 202. An initial one of the plurality of time periods may have a first duration and a subsequent time period may have a second duration longer than the first duration. The adjacent time periods may be separated from one another by a time gap. For example, the applied voltage may include a plurality of voltage pulses, one for each of the plurality of time periods, where there may be a time gap in between consecutive pulses.

The control module 210 can then take appropriate action in controlling the main unit 202. The control module 210 can operate the airflow generator 208 in either a first mode (in which power Is provided by the main unit 202 to the airflow generator 208 and an airflow is generated) and a second mode (in which power is not provided to the airflow generator 208 and an airflow is not generated). In particular, when the control module 210 determines that the cleaner head 10 is attached to the main unit 202, the control module 210 can control the operational mode of airflow generator 208 to be in the second mode (off), such that no airflow is provided by the main unit 202, as such airflow is not needed for the cleaner head 10. For other cleaner heads, the operational mode of the airflow generator 208 may instead be controlled to provide an airflow where such airflow is appropriate. When it is determined that there is no cleaner head attached to the main unit 202, the control module also controls the airflow generator to operate in the first mode.

Although the cleaner head 10 is detected here by looking at current profiles, other methods of detection, for example including communication from the cleaner head 10 to the control module via a wired and/or wireless connection, that enable the control module 210 to turn off the airflow generator 208 are also envisaged.

With the cleaner head 10 attached to the main unit 202, power is supplied from the battery 206 of the main unit 202 via looming (not shown) to the cleaner head 10, and in particular to the control circuitry 78, the roller drive 80, and the pump 84. With other cleaner heads attached to the main unit 202, power may also be supplied to these cleaner heads from the battery 206. However, power is not provided to the terminal of the main unit 202 when it is determined that no cleaner head is attached to the main unit 202.

The pump 84 drives distribution of liquid from the liquid distribution tank 34. The pump 84 is controlled by the control circuitry 78 to operate in a pulsed or cyclical manner, as noted previously, with the pump 84 controlled to be on for a first duration of 0.25 seconds, to be off for a second duration of 6 seconds, and so on. In other words, for each pulse, the first duration is around 4% of the second duration. This causes liquid to be moved from the liquid distribution tank 34, through the liquid tube 86, to the reservoir 88. In particular, liquid is driven by the pump 84 via the reservoir inlet 114 to the reservoir 88, and liquid is delivered to the pile 122 of the roller 14 via the reservoir outlets 116. The pressure within the reservoir 88 is such that liquid exits the reservoir 88 through the reservoir outlets 116, and drips onto the distribution surface 90. The configuration of the reservoir 88 and the operation of the pump 84 is such that the liquid flow rate through the reservoir is around 30ml/min. The pump 84, the liquid tube 86, the reservoir 88, and the distribution surface 90 together provide a liquid delivery assembly for delivering liquid to the roller 14 (in particular, the pile 122 of the roller 14). The liquid pools on the distribution surface 90 and is gradually distributed to the roller 14 by simply falling from the distribution surface 90 onto the pile 122 of the roller 14. The roller 14 is wetted at a rate of around 30ml/min. With the roller 14 wetted by the liquid, the cleaner head 10 can be moved across a surface to be cleaned by the user. The roller drive 80 is controlled to rotate the roller 14 at around 900-1000rpm. As the roller 14 rotates and is moved across the surface to be cleaned, the roller 14 can impart a wiping force to the surface to be cleaned. The squeegee 58 contacts the surface to be cleaned and ensures that no dirty liquid from the surface being cleaned passes toward the rear of the cleaner head 10.

The roller 14 causes displacement of liquid (from the surface to be cleaned) into the combined inlet/outlet 65 of the liquid collection tank 36.

In particular, the rotation of the roller 14 and the curved nature of the front wall 56 of the liquid collection tank ensures that dirty liquid, and debris, passes from the surface being cleaned to the interior volume of the cleaner head 10. The roller 14 directs the dirty liquid and debris toward the squeegee 58 and the rotational energy generated via rotation of the roller 14 pushes the dirty liquid and debris upwards along the front wall 56 into the main tank body 50 of the liquid collection tank 36.

Further, as previously noted, the mangle 92 contacts the roller 14, in particular, it extends into the pile 122 of the roller 14. As the roller 14 rotates, the roller 14 is driven so that the roller 14 impinges the mangle 92 from below. In such a manner the pile 122 contacts the mangle 92, the mangle 92 acts to scrape dirty liquid and debris from the pile 122 of the roller 14. Accordingly, the liquid carried by the roller 14 is displaced into the combined inlet/outlet 65 of the liquid collection tank 36 in use. The speed of the roller 14 at the mangle 92 is around 5 to 7 m/s, which has been found to be particularly good for removal of dirty liquid and debris from the pile 122 of the roller 14. Speeds of between around 3m/s to 8m/s are also envisaged. The positioning and shape of the mangle 92 results in dirty liquid and debris being passed rearwardly toward the liquid collection tank 36.

Such dirty liquid and debris is guided by a curved portion 89 of the intermediate plate 87 (adjacent to the mangle 92) and/or the sloped surface 64 of the removable cover 54 through the combined inlet/outlet 65 into the interior of the main tank body 50 of the liquid collection tank 36. For example, the dirty liquid and debris is guided by the curved portion 89 along a curved path towards the liquid collection tank 36. As shown in Figure 12, the curved portion 89 is concave from the perspective of the surface to be cleaned when the cleaner head 10 is located on the surface to be cleaned in use. With the configuration of the cleaner head 10 described above, the roller 14 (in particular the pile 122 of the roller 14) is maintained at a saturation level of between 25% and 28% in use. Such a saturation level has been found to be effective at cleaning a surface to be cleaned, without the need to distribute excessive levels of liquid onto the surface. Efficient cleaning may also be achieved with a saturation level of between 10% and 30%.

When desired, for example when there is no remaining liquid in the liquid distribution tank 34, the cleaner head 10 can be removed from the main unit 202 of the appliance 200. The cleaner head 10 can then be disassembled in the manner previously described to enable the liquid collection tank 36 to be emptied, and the liquid distribution tank 34 to be refilled.

In an embodiment of this disclosure, a cleaner head for an appliance may be provided with the following clauses.

1 . A cleaner head for an appliance, the cleaner head comprising: a roller comprising a material for contacting a surface to be cleaned; and a liquid delivery assembly for delivering liquid to the material; wherein the liquid delivery assembly is configured to deliver liquid to the material so that the material is between 10% and 30% saturated with liquid.

2. A cleaner head according to clause 1 , wherein the liquid delivery assembly is configured to deliver liquid to the material so that the material is between 25% and 28% saturated with liquid.

3. A cleaner head according to clause 1 or clause 2, wherein the liquid delivery assembly is configured to deliver liquid to the material at a rate of between 25 and 35 millilitres per minute.

4. A cleaner head according to any one of the preceding clauses, wherein a surface area of the material is between 800 and 900 square centimetres.

5. A cleaner head according to any one of the preceding clauses, wherein the material is microfibre having a density of between 46500 and 85250 fibres per square centimetre.

6. A cleaner head according to any one of the preceding clauses, wherein the cleaner head comprises a roller drive configured to drive rotation of the roller while the liquid delivery assembly delivers liquid to the material. 7. A cleaner head according to clause 5, wherein the roller drive is configured to drive rotation of the roller at a rate between 500 and 1200 revolutions per minute.

8. A cleaner head according to any one of the preceding clauses, wherein the cleaner head comprises a mangle configured to remove liquid and/or debris from the material.

9. The cleaner head according to clause 7, wherein the mangle penetrates into the material a distance of between 2 and 3 millimetres.

10. A cleaner head according to any one of the preceding clauses, wherein the liquid delivery assembly comprises a drive component for driving distribution of liquid to the material.

11. A cleaner head according to clause 10, wherein the drive component is configured to drive the distribution of liquid to the material in pulses.

12. A cleaner head according to clause 11 , wherein the drive component is configured to drive the distribution of liquid for a first duration to generate each pulse; and consecutive pulses are separated by a second duration in which the drive component does not drive the distribution of liquid.

13. A cleaner head according to clause 12, wherein the first duration is between 2% and 9% of the second duration.

14. A cleaner head according to clause 12 or 13, wherein the first duration is 0.25 seconds.

15. A cleaner head according to any one of clauses 12 to 14, wherein the second duration is between 3 seconds and 10 seconds.

16. A cleaner head according to any one of clauses 12 to 15, wherein the cleaner head comprises a roller drive configured to drive rotation of the roller, and wherein the first duration lasts for at least one revolution of the roller.

17. A cleaner head according to claim 16, wherein the first duration lasts for between 2 and 5 revolutions of the roller. 18. A cleaner head according to any one of clauses 10 to 17, wherein the liquid delivery assembly comprises a reservoir to which liquid is driven by the drive component via a reservoir inlet, wherein the reservoir comprises a plurality of outlets via which liquid is delivered to the material.

19. A cleaner head according to clause 18, wherein the liquid delivery assembly comprises a distribution surface for distributing liquid onto the material, the distribution surface extending in a direction parallel to the rotational axis of the roller, the distribution surface being provided with liquid from the outlets of the reservoir.

20. A cleaner head according to any one of clauses 10 to 19, wherein the cleaner head further comprises a liquid distribution tank for storing liquid to be distributed to the material by the drive component.

21. An appliance comprising a cleaner head according to any one of the preceding clauses.

22. An appliance according to clause 21 , wherein the appliance comprises a main unit, and the cleaner head is releasably attachable to the main unit.

23. An appliance according to clause 22, when dependant on clause 6 and/or clause 10, wherein the main unit comprises a power supply for supplying electrical power to the drive component and/or the roller drive.

In another embodiment of this disclosure, a cleaner head for an appliance may be provided with the following clauses.

1. A cleaner head for an appliance, the cleaner head comprising: a roller for contacting a surface to be cleaned; a roller drive configured to drive rotation of the roller; and a mangle configured to contact the roller to remove liquid from the roller rotating in use; wherein the roller drive is configured to, in use, drive rotation of the roller such that the speed of the roller at the mangle is between 3 and 8 meters per second.

2. The cleaner head according to clause 1 , wherein the roller drive is configured to drive rotation of the roller at between 500 and 1200 revolutions per minute.

3. The cleaner head according to clause 1 or 2, wherein the roller drive is configured to, in use, drive rotation of the roller such that the speed of the roller at the mangle is between 5 and 7 meters per second. 4. The cleaner head according to any one of the preceding clauses, wherein the roller drive is configured to drive rotation of the roller at between 900 and 1000 revolutions per minute.

5. The cleaner head according to any one of the preceding clauses, wherein the radius of the roller is between 58 and 62 millimetres.

6. The cleaner head according to any one of the preceding clauses, wherein the roller comprises a material for contacting the surface to be cleaned, and the mangle penetrates into the material for removing liquid from the material of the roller rotating in use.

7. The cleaner head according to clause 6, wherein the thickness of the material is around 5 millimetres.

8. The cleaner head according to clause 6 or 7, wherein the mangle penetrates into the material a distance of between 2 and 3 millimetres.

9. The cleaner head according to any one of clauses 6 to 8, wherein the material is microfibre having a density of between 46500 and 85250 fibres per square centimetre.

10. The cleaner head according to any one of the preceding clauses, wherein the mangle is positioned on the roller at an angular displacement of between 30 and 60 degrees, about the rotational axis of the roller, from a plane passing through the rotational axis of the roller and parallel to the surface to be cleaned when the cleaner head is located on the surface to be cleaned in use.

11. The cleaner head according to any one of the preceding clauses, wherein the cleaner head further comprises a liquid collection tank for collecting the liquid removed from the roller by the mangle in use.

12. The cleaner head according to clause 11 , wherein the liquid collection tank has an inlet through which liquid removed by the mangle enters the liquid collection tank, and wherein, relative to the surface to be cleaned when the cleaner head is located on the surface to be cleaned in use, the height of the mangle is between 3 and 5 millimetres more than the height of the inlet of the liquid collection tank. 13. The cleaner head according to clause 11 or 12, wherein the cleaner head comprises, adjacent to the mangle, a curved portion configured to guide the liquid removed from the roller by the mangle along a curved path towards the liquid collection tank.

14. The cleaner head according to clause 13, wherein the curved portion is concave from the perspective of the surface to be cleaned when the cleaner head is located on the surface to be cleaned in use.

15. An appliance comprising a cleaner head according to any one of the preceding clauses.

16. An appliance according to clause 15, wherein the appliance comprises a main unit, and the cleaner head is releasably attachable to the main unit.

17. An appliance according to clause 16, wherein the main unit comprises a power supply for supplying electrical power to the roller drive.

Whilst particular examples and embodiments have thus far been described, it should be understood that these are illustrative only and that various modifications may be made without departing from the scope of the invention as defined by the claims. For example, the values of various parameters and dimensions described in conjunction with the specific embodiment above may be varied within a reasonable tolerance range that will be apparent to a person skilled in the art without significantly modifying operation of the cleaner head 10.