Floor tool for a cleaning appliance

A floor tool for a cleaning appliance including a cleaner head rotatably attached to a conduit carried by a pair of wheels that converge beneath the conduit.

REFERENCE TO RELATED APPLICATIONS

This application claims the priority of United Kingdom Application No. 0823191.2, filed Dec. 19, 2008, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a floor tool for a cleaning appliance.

BACKGROUND OF THE INVENTION

Cleaning appliances, such as vacuum cleaners, floor polishers and shampoo machines, may include a hose-and-wand assembly to which different accessories may be attached. One such accessory is a floor tool which a user manoeuvres back and forth over a surface to be cleaned. The floor tool may include wheels which aid the user in manoeuvring the floor tool. However, there is often difficultly in manoeuvring the floor tool in directions beyond that of a straight line.

SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a floor tool for a cleaning appliance comprising a cleaner head rotatably attached to a conduit carried by a pair of wheels that converge beneath the conduit, wherein the wheels have axes of rotation that intersect above a line passing through the wheel centres.

In a second aspect, the present invention provides a floor tool for a cleaning appliance comprising a cleaner head rotatably attached to a conduit carried by a pair of dome-shaped wheels, the wheels having axes of rotation that are oriented such that the wheels converge beneath the conduit.

In a third aspect, the present invention provides a floor tool for a cleaning appliance comprising a cleaner head rotatably attached to a conduit carried by two wheels only that converge beneath the conduit.

In each aspect, the conduit fluidly couples the cleaner head to the cleaning appliance such that fluid may be carried between the cleaning appliance and a surface to be cleaned. The free end of the conduit may be adapted for releasable attachment to a wand, hose or like duct of the cleaning appliance. Alternatively, the conduit may final an integral part of the cleaning appliance.

In converging beneath the conduit, the wheels rotate about axes of rotation that are oriented such that the separation between the wheels is smallest beneath the conduit. In providing convergent wheels, a space is defined between the two wheels through which the conduit can pass. Accordingly, the floor tool is supported by wheels that do not unduly increase the size, and in particular the height, of the floor tool.

By including a bend in the conduit, movement of the floor tool beyond that of a straight line is made possible by rotating the free end of the conduit. To facilitate steering of the floor tool, the conduit preferably comprises a forward portion that is pivotally attached to a rearward portion. The wheels are then rotatably attached to the forward portion, which is in turn rotatably attached to the cleaner head. This arrangement additionally helps to prevent the cleaner head being inadvertently lifted as the floor tool is manoeuvred over the cleaning surface. Advantageously, the rearward portion is attached to the forward portion at points above those at which the wheels are attached to the forward portion. Consequently, the length of the conduit may be kept to a minimum, resulting in a more compact floor tool.

The wheels are preferably dome-shaped. Accordingly, as the conduit rotates relative to the cleaner head, the wheels continue to provide a rolling support. Moreover, the wheels advantageously provide a substantially continuous arcuate support in the plane normal to the longitudinal axis of the conduit. Consequently, as the floor tool is steered in different directions, a smooth transition occurs as support moves from one wheel to the next. Indeed, in order that, from the point of the user, the transition between wheels feels continuous, the gap between the wheels preferably subtends an angle at the centre of the conduit of no more than 20 degrees. That is to say that, in the plane normal to the longitudinal axis of the conduit, the gap subtends an angle of no more than 20 degrees at the longitudinal axis of the conduit.

The surfaces of the wheels are preferably coincident with a common sphere. Moreover, the centre of the common sphere is ideally coincident with the longitudinal axis of the conduit. Consequently, as the conduit rotates relative to the cleaner head, the conduit maintains the same height above the cleaning surface. This then helps prevent lifting of the cleaner head as the floor tool is steered in different directions.

In order that the present invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

DETAILED DESCRIPTION OF THE INVENTION

The floor tool1ofFIGS. 1 to 4comprises a cleaner head2rotatably attached to a coupling3. The free end of the coupling3is attachable to a wand, hose or other such duct of a cleaning appliance (not shown).

The cleaner head2comprises a housing4, a brushbar5and a motor6. The housing4defines a chamber7within which the brushbar5is rotatably mounted, and an outlet duct8that extends from the chamber7to the rear of the cleaner head2. An opening9formed on the underside of the housing2provides an inlet to the chamber7. The brushbar5is driven by the motor6, which is located to the rear of the cleaner head2beneath the outlet duct8. The motor6is coupled to an electrical terminal11provided at an end of the outlet duct8, through which electrical power may be delivered to the motor6.

The coupling3comprises a conduit14carried by a pair of wheels15,16, an electrical terminal17,18provided at each end of the conduit14, and an electrical cable19that extends between the electrical terminals17,18.

The conduit14comprises a forward portion20, a rearward portion21, and a flexible hose22.

The forward portion20is pivotally attached at one end to the rearward portion21. The other end of the forward portion20is shaped as a cylindrical collar that receives the end of the outlet duct8. An annular groove23,24is formed around each of the forward portion20and the outlet duct8into which a snap ring25is seated. The snap ring25extends between the two grooves23,24such that relative rotation of the forward portion20and outlet duct8is possible while relative separation is not. A gasket26made of resilient material (e.g. rubber or foam) is provided within the forward portion20. The outlet duct8, when received within the forward portion20, abuts and compresses the gasket26to form a seal between the cleaner head2and the coupling3. The surface of the gasket26is coated with a low friction material (e.g. PTFE or HDPE) such that relative rotation of the outlet duct8and forward portion20does not result in adverse wearing of the gasket26.

One end of the rearward portion21is pivotally attached to the forward portion20, while the other end is shaped for attachment to a wand, hose or other such duct of a cleaning appliance.

The hose22is held within and extends between the forward and the rearward portions20,21respectively. The hose22is ribbed such that the length of the hose22can be made to expand and contract. Consequently, as the rearward portion21pivots relative to the forward portion20, the length of the hose22varies to accommodate the change.

Each wheel15,16is domed-shaped and is rotatably attached to the forward portion20. One wheel15rotates about a first axis of rotation27and the other wheel16rotates about a second axis of rotation28. The axes of rotation27,28are non-parallel and lie in a common plane normal to the longitudinal axis of the forward portion20. More specifically, the first axis27is tiled by +θ and the second axis is tilted by −θ relative to a line29passing through the wheel centres, the tilt occurring in the common plane. Consequently, the two axes of rotation27,28intersect one another at a point that is spaced above the line29passing through the wheel centres. Owing to the tilt in the axes of rotation27,28, the wheels15,16converge beneath the conduit14, i.e. the separation between the wheels15,16is smallest beneath the conduit14.

The curvature of each dome-shaped wheel15,16is spherical. Furthermore, the two wheels15,16are arranged (i.e. spaced from one another and tilted) such that the surfaces of the wheels15,16are coincident with a common sphere30. The surfaces of the two wheels15,16may thus be regarded as defined by an imaginary sphere30from which a v-shaped wedge has been removed (this is perhaps best visualised inFIG. 5). The centre of this common sphere30is coincident with the longitudinal axis of the forward portion20, the advantage of which is outlined below.

The electrical terminals17,18of the coupling3are located at the ends of the forward and rearward portions20,21. The terminals11,17of the outlet duct8and the forward portion20forms a slip ring arrangement so as to permit relative rotation. The electrical cable19extends between and connects the terminals17,18of the forward and rearward portions20,21. From the terminal17provided on the forward portion20, the cable19extends between the forward portion20and the hose22, divides in two with each half passing through a pivot formed between the forward and rearward portions20,21, and extends between rearward portion21and the hose22.

The floor tool1is intended to be used with a cleaning appliance that carries fluid to and/or from a surface, e.g. wet/dry vacuum cleaners, polishing/waxing machines and carpet shampoo machines. The floor tool1is manoeuvred over the surface to be cleaned by means of a duct of the cleaning appliance. The duct includes an electrical terminal that mates with the electrical terminal18provided on the rearward portion21. Electrical power is thus delivered by the cleaning appliance to the motor6of the cleaner head2, which in turn drives the brushbar5to agitate the cleaning surface and/or massage a fluid into the surface.

As the floor tool1is manoeuvred forwards and backwards, the forward portion20of the coupling3pivots relative to the rearward portion21such that the cleaner head2maintains a flat profile with the cleaning surface. Steering of the floor tool1is achieved by rotating the duct of the cleaning appliance, which in turn causes the rearward portion21of the coupling3to rotate about its longitudinal axis. When manoeuvring the floor tool1, the rearward portion21is normally angled relative to the forward portion20. Consequently, as the rearward portion21rotates about its longitudinal axis, the forward portion20is caused to precess about the longitudinal axis of the rearward portion21. Owing to the weight of the cleaner head2, as well as the pivot formed between the forward and rearward portions20,21, rather than precessing in a cone-like manner, the forward portion20precesses in a plane parallel to the cleaning surface. The net result is that the cleaner head2moves to the right or left in response to clockwise or anticlockwise rotation of the duct of the cleaning appliance. As the cleaner head2moves to the right or left, the outlet duct8rotates relative to the forward portion20such that the cleaner head2maintains a flat profile with the cleaning surface.

As the floor tool1is manoeuvred forwards and backwards, the wheels15,16of the coupling3rotate to provide a rolling support for the conduit14. In response to steering the floor tool1, the forward portion20rotates about its longitudinal axis. As the forward portion20rotates, one of the two wheels15,16maintains contact with the cleaning surface and thus continues to provide rolling support for the conduit14. The surfaces of the wheels15,16are coincident with a common sphere30, the centre of which is coincident with the longitudinal axis of the forward portion20. Consequently, as the forward portion20rotates about its longitudinal axis, the wheels15,16continue to support the forward portion20at the same height above the cleaning surface. No lifting of the cleaner head2therefore occurs and a flat profile with the cleaning surface is maintained.

The rolling support provided by the wheels15,16describes an arc in the plane normal to the longitudinal axis of the forward portion20. This arcuate rolling support includes a small discontinuity at the gap between the two wheels15,16. The discontinuity, however, is sufficiently small that, from the point of view of a user, the rolling support feels continuous.

Since the floor tool1is moved predominantly in a forward and backward direction, ease of movement would be greatest if both wheels15,16were to rotate about a single horizontal axis. However, if the wheels15,16were to rotate about a single horizontal axis, hemispherical wheels would be required in order to provide a continuous rolling support. Such an arrangement would leave no space for the conduit14to pass between the wheels15,16. The angle by which the rotational axes27,28are tilted is therefore ideally as small as possible while permitting sufficient space for the conduit14to pass between the wheels15,16. The angle of tilt will thus depend upon the diameter of the conduit14as well as the diameter of the common sphere30coincident with the wheel surfaces. By way of example,FIG. 7illustrates two arrangements in which (a) a small diameter conduit14and (b) a large diameter conduit14are employed; in both arrangements, the diameter of the common sphere30of the wheels15,16is the same.

In the embodiment described above, the wheels15,16have axes of rotation27,28that lie in a common plane. However, the wheels15,16may toe in or out such that the axes of rotation27,28do not lie in a common plane. The axes of rotation27,28nevertheless intersect at a point spaced above the line29passing through the wheel centres, albeit not directly above the line29.

As can be seen inFIG. 4, the rearward portion21is pivotally attached to the forward portion20at points directly above those points at which the wheels15,16are attached to the forward portion20. Consequently, the overall length of the conduit14may be kept to a minimum, resulting in a more compact floor tool1. Nevertheless, the points at which the rearward portion21attaches to the forward portion20may be located elsewhere.

In the embodiment described above, the cleaner head2includes a brushbar5that is driven by a motor6. However, the cleaner head2may include alternative means for agitating or otherwise working a surface to be cleaned. By way of example, the brushbar5may be driven by an air turbine rather than a motor. Alternatively, the brushbar5and motor6may be omitted altogether from the cleaner head2. There are therefore applications for which the electrical terminals17,18and cable19may be omitted from the coupling3.

Wheels15,16having surfaces that are coincident with a common sphere30have the advantage that the forward portion20maintains the same height above the cleaning surface as the forward portion20rotates. Nevertheless, there may be applications for which it is advantageous to have a forward portion20that increases or decreases in height with rotation. Accordingly, it is not essential that the surfaces of the wheels15,16have spherical curvature or that the surfaces are coincident with a common sphere. Moreover, the dome-shaped wheels need not be continuously curved but may include a flat section at the wheel axes.

In the embodiment described above, the conduit14comprises a forward portion20pivotally attached to a rearward portion21. The provision of a pivot has the advantage of ensuring that the cleaner head2maintains a flat profile with the cleaning surface as the floor tool1is manoeuvred back and forth. Nevertheless, there may be applications for which a pivot within the conduit14may not be necessary. By way of example, the outlet duct8of the cleaner head2may be pivotally attached to the remainder of the cleaner head2. In this instance, the conduit14may be formed as a unitary element having an elbow or bend such that rotation of the conduit14continues to bring about steering of the cleaner head2.

While the cleaner head2and the coupling3are attached in a manner that is intended to prevent their separation, the two may be adapted for separable attachment. The coupling3may then be used with different cleaner heads to form a floor tool1. Moreover, while the coupling3is intended to be releasably attached to a duct of a cleaning appliance, the coupling3may alternatively form an integral part of the cleaning appliance. The cleaning appliance may then be used with different, interchangeable cleaner heads.

Conventional floor tools often include wheels that aid in manoeuvring the floor tool. However, movement of the floor tool is typically constrained to that along a straight line. In contrast, the floor tool1of the present invention can be manoeuvred in directions beyond that of a straight line.

Floor tools capable of movement beyond a straight line are known. In one example, a pair of wheels is arranged on opposite sides of a conduit attached to a cleaner head. The wheels rotate about a common horizontal axis such that, when steering the floor tool, one of the wheels lifts off the cleaning surface. Additionally, the conduit rocks to one side causing the height of the conduit above the cleaning surface to increase. This in turn causes the rear of the cleaner head to lift off the cleaning surface resulting in loss of performance. Furthermore, the lifting of the cleaner head places a strain on the arm of the user and thus repeated steering of the floor tool can become tiring. In a further example, a cleaner head is attached to a conduit carried by three wheels. A barrel-shaped wheel sits below the conduit and two larger wheels are located on opposite sides of the conduit. This arrangement has the advantage that, as the floor tool is steered left or right, the height of the conduit above the cleaning surface is unchanged and thus the cleaner head maintains a flat profile with the surface. Nevertheless, the floor tool is relatively bulky owing to the presence of three wheels. In particular, since the conduit sits on top of the barrel-shaped wheel, the height of the floor tool is relatively high. Additionally, the provision of three wheels increases the weight and cost of the floor tool.

With the floor tool of the present invention, a substantially continuous rolling support is provided by two wheels only. Accordingly, the floor tool is both lighter and cheaper than the aforementioned floor tool having three wheels. Moreover, the conduit of the floor tool passes between, rather than over, the wheels and thus the floor tool is more compact. In particular, the floor tool is of lower height, making it well-suited at cleaning beneath structures of particularly low profile. As the floor tool is steered to the left or right, the conduit (or at least that portion of the conduit attached to the cleaner head) maintains the same height above the cleaning surface. Consequently, the cleaner head maintains a flat profile with the cleaning surface and no loss of performance occurs. Additionally, in comparison to the aforementioned floor tool having two wheels, less effort is required on the part of the user to steer the floor tool. Furthermore, the floor tool is capable of tighter turns.