DESCRIPTION OF THE RELATED ART Currently there are a number of small rotary brushes on the market which are driven by water pressure. The designs are based on a water wheel design. Consequently, this type of brush operates at very low torque and is only suitable for use on vehicles and for wheel cleaning, since the maximum brush head diameter is around 180 mm.

It is therefore desirable to provide a high torque floor cleaning tool using a large brush/scrubbing head, which can be driven by high pressure water.

SUMMARY OF THE PRESENT INVENTION According to the present invention there is provided a rotating tool including a rotatable working element and a drive unit for causing rotation of the working element, wherein the drive unit comprises a liquid inlet, a rotor which is rotatable about an axis, and an outlet which is carried by the rotor and which serves to direct liquid supplied through the liquid inlet in a direction to cause the rotor to rotate about the axis, and an output shaft for transferring rotary motion to the working element.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a side sectional view of a brush tool embodying the present invention; Figure 2 shows a plan view of the tool of Figure 1; Figure 3 shows an enlarged side sectional view of the drive system of the tool of Figure 1; Figure 4 shows a sectional plan view of part of the drive system of the tool of Figure 1; Figure 5 and 6 show views of an optional addition

to the tool of Figure 1; and Figure 7 shows a second tool embodying the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A brush tool 1 embodying the present invention is shown in Figures 1 and 2, and comprises a drive unit 2 which is attached to a rigid handle 3. A brush unit housing 4 is rigidly attached to the drive unit 2, and contains a brush element 5.

The handle 3 incorporates a rubber hand grip 6 and a quick release coupling water supply inlet 7. The handle 3 is pivotally attached to the brush unit housing 4, by way of swivel hinge joints 8.

The drive unit 2 includes a water inlet connection 9, which is connected to a water pipe 10. The water pipe 10 connects via the quick release coupling 7 to a water supply (not shown) which supplies water at high pressure to the brush tool 1. Preferably, water is supplied at 1000 psi to 3000 psi (approx 70 to 210 bar; 7 to 21 MPa) from an industrial power washer.

As shown in more detail in Figure 3, a hollow water supply shaft 11 extends from the water inlet 9 and serves to support a hollow rotor 12. The shaft 11 and rotor 12 are supported on bearings 13 and are rotatable with respect to the water inlet 9 about a vertical axis. A coupling 14 is provided between the water inlet 9 and the shaft/rotor 11,12. The coupling 14 comprises a first part which is fixed to the water inlet 9, and a second part which rotates with the shaft 11. The coupling thereby provides a rotary seal for transmission of water to the shaft 11 and rotor 12.

An output shaft 15 is attached to the rotor 12 and is rotatable with the rotor. Water is supplied into the water inlet 9, via a connection 16, and to the rotor 12, via the coupling 14 and the shaft 11.

As is more clearly shown in Figure 4, the rotor 12

carries arms 17 which define passageways 18 which extend from the rotor 12 to the free end of the arms 17. The passageway 18 communicates with the hollow rotor 12. Water supplied to the water inlet 9 is thus communicated to the free ends of the arms 17.

Each arm 17 carries a nozzle 19 which extends at right angles to the arm, i. e. in a direction at right angles to the radius of the shaft 11. Each nozzle 19 includes a passageway 20 which communicates with the passageway 18.

The rotor 12 carries an output driveshaft 21 which extends away from the rotor 12 and which carries an output gear 22. The driveshaft 21 is supported on bearings 23 in the brush unit housing 4.

In use, high pressure water is supplied to the water inlet 9, the water is channelled through the shaft 11 and rotor 12 along the passageways 18 and 20 and ejected from the nozzles 19. Since the water is ejected from the nozzle at right angles to the arms 17, the rotor 12 is caused to rotate with respect to the water inlet 9 about the vertical axis. Thus, the shaft 11 and output driveshaft 21 are also caused to rotate.

Water ejected from the nozzles 19 falls through drains 24 in the drive unit into the brush unit housing 4.

The brush unit 4 carries a driveshaft 25 which is free to rotate with respect to the brush unit 4, and which carries a drive gear 26. The drive gear 26 engages with the drive output gear 22, so that when the output gear 22 rotates the drive gear 26 rotates. The shaft 25 carries the brush element 5, so that rotation of the drive gear 26 causes rotation of the brush element5. The brush element 5 can be any type of brush or floor cleaning pad. Water ejected from the drive unit is supplied to the brush or pad.

Thus, as will be readily apparent from Figures 1

to 4, supply of high pressure water along the supply pipe 7 to the inlet 9 and through shaft 11 and rotor 12 eventually to the nozzles 19 causes the drive unit 2 to provide an output drive via gear 22 which drives the brush element 5.

Water which is discarded from the drive unit 2 is used as the cleaning solution for the brush. The water supply can be hot or cold (5°C to 120°C) and an ideal flow rate would be 81/min to 201/min at a pressure of 1000 psi to 3000 psi (approx 70 to 210 bar; 7 to 21 MPa).

The brush element can be a large head (e. g. 565 mm diameter) for floor cleaning, or could be a smaller head (e. g. around 150 mm diameter) for cleaning vehicles etc.

Embodiments of the present invention include a simple drive system which does not require provision of an electrical power source, or indeed any power source, and which utilizes the water supply which is in any case required.

The drive unit 2 can be coupled to the brush element 27 by way of any convenient system. For example, in addition to the simple geared drive system already described, a gearbox, such as an epicyclic gearbox, could be used to transfer rotary power from the drive system to the brush element.

The cleaning tool is particularly suited to cleaning brick paving and stone work since sand is not washed away by the cleaning action.

It will be appreciated that the drive unit 2 could be used to power other equipment requiring a rotary drive. For example the drive system could be used to drive a floor cutting tool, the brush element being replaced by an alternative working element such as a cutting wheel. Such a cutting tool could be used for cutting tarmacadam, concrete etc..

Figures 5 and 6 of the drawings illustrate an optional addition to the tool shown in and described with reference to figures 1 to 4. A pump unit 30 can be used to recycle some of the water used for the powering and cleaning operation. The pump 30 has a water inlet 31 and a water outlet 32. Water is pumped back to the reservoir of the cleaning system for reuse by the cleaning tool. The pump is driven is a similar manner to the brush element itself. A gear 33 of the pump 30 engages with the drive gear 26 of the brush unit 4, so that rotation of the drive gear 26 causes rotation of the pump drive gear 33 and hence operation of the pump. As with the brush element, it is possible to drive the pump from the drive unit with any suitable means, such as with an epicyclic gearbox.

Figure 6 of the drawings shows a second embodiment of the present invention which uses a drive system similar to the system described above. The tool 40 of Figure 6 comprises a tool body 41 from which a pair of carrying handles 42 project. The carrying handles enable the tool to be used similar to the manner of using a hydraulic road drill.

The tool body 41 houses a drive system 43 which operates in the same manner as described above. Since the actual operation of the drive system is the same as previously described, a full explanation will not be repeated. The drive system serves to drive a shaft 44 which extends through the tool body 41. The drive shaft is supported by bearings 45 and 46 and carries at one end a brush element 47. The brush element 47 is preferably a wire brush, and is smaller in diameter than the brush element of the previous embodiment.

Water is pumped to the tool via a water inlet 48, and is fed to the drive system 43. The water is fed to nozzles carried by arms which are free to rotate, as before. Water is expelled from the nozzles so as to

cause the arms to rotate and so to impart rotary motion to the drive shaft. The brush element is thereby caused to rotate.

The embodiment of Figure 6 is particularly suited to removing chewing gum and other sticky substances from paving and the like. The water fed to the drive system also acts as a cleaning fluid, as before. Hot water is most suitable for the removal of chewing gum etc..