GB2444773A - A flexible rotary coupling for a floor cleaner - Google Patents

Abstract

A rotary coupling, comprises first and second portions arranged for rotation about an axis. Disposed between said portions is a resiliently flexible element 15. Said coupling is particularly for connecting the floor-engaging tool 19 of a rotary floor treatment appliance to the drive motor of the appliance. A resiliently flexible disc 15 of elastomeric material, is connected at its centre to a rotatably driven portion 10 and at its periphery to an annular tool support plate 16. The disc 15 dampens vibrations and decouples the user of the apparatus from any forces which may occur as the tool 19 is moved across the floor. The disc may be provided with means for varying the flexibility and or resilience of the coupling. A further means 21 (for example a collar) may be included to shorten the radial extent of the flexible coupling and thus vary the flexibility and or resilience.

Description

ROTARY COUPLING

This invention relates to a rotary coupling and more particularly to a coupling for connecting the floor-engaging tool of a rotary floor treatment appliance to the drive motor of the appliance.

Rotary appliances for abrading, cleaning, drying, polishing and scouring floors are well known. Generally such appliances comprise a body and a depending brush pad or other floor-engaging tool, which is driven about a vertical axis of rotation by a motor mounted inside the body. A handle extends from the body for manoeuvring and guiding the appliance by gently tipping the body in an appropriate direction to cause the apparatus to move across the floor, to the left or right, or forward or backward. Alternatively, larger apparatus may comprise a self-propelled vehicle with the brush, pad or other floor-engaging tool being mounted underneath.

The speed of rotation of the drive motor depends upon the application and typically, rotational speeds in range of 100 to 200 rpm are suited to the wet scrubbing of hard surfaces and speeds in range of 300 to 500rpm are suited to damp and dry polishing.

Grinding applications require even higher rotational speeds, with high gloss cleaning finishes being best obtained at speeds exceeding 1000 rpm.

Pads for cleaning and polishing floors typically comprise a flat annular member formed of non-woven synthetic fibres, whereas for brushes for cleaning and polishing floors typically comprise a plurality of bristles extending axially from an annular carrier. Low speed floor cleaning and polishing apparatus comprise such a brush, pad or other tool detachably connected to a generally flat circular drive plate of the apparatus by means of a hook-and-pile type fastening arrangement. The centre of the drive plate has a quick release flange clutch fitting, which attaches to the drive shaft of the motor. High speed apparatus comprise a layer of foamed plastics material disposed between the hook-and-pile type fastening and the drive plate to help reduce the transmission of vibrations.

It has been found that the fastenings used in low speed apparatus are unsuitable for use on higher speed floor cleaning and polishing apparatus because at high speed, a large amount of torque is generated, particularly at start up or when the floor pad encounters localised resistance especially under only a portion of the pad. For example, if the cleaning pad encounters a rough surface or a particularly adherent substance on the floor, the balanced torque is immediately transformed into a violent movement, where the movement arm is the radial distance from the centre of the motor drive to the point where the resistance is encountered. This movement produces a vibration of the entire apparatus, which is transmifted along the handle of the apparatus to the operator, rendering the apparatus difficult to control and uncomfortable to use. Continued use may even cause the operator to suffer long-term medical problems, such as repetitive strain injury. Such vibration will also reduce the quality of the finish achieved by the apparatus and may also damage the apparatus.

In higher speed apparatus, the provision of the foamed plastics layer helps to absorb some of the vibration, by the layer compressing as the pad encounters resistance or floor irregularities the layer then returning to its original thickness as the pad rotates away from the resistance. This action only absorbs the upward shocks encountered when cleaning a floor and does not cure other causes of vibration, such as an out of balance cleaning pad. It is also common practice for the apparatus operator to store the cleaning apparatus resting on the foamed plastics layer: even after a short period of time, the weight of the apparatus causes the layer to become permanently compressed, thereby reducing its effect.

There is now a desire to produce cleaning apparatus which can operate at a range of speeds, thus making it more convenient for the operator to carry out a wider range of cleaning tasks. However, because the existing pad and brush fastenings are unable to operate satisfactorily at higher speeds, the apparatus operator would need two sets of pad holders.

We have now devised a rotary coupling which can be used in rotary floor treatment appliances to alleviate the above-mentioned problems.

In accordance with this invention, there is provided a rotary coupling comprising first and second portions arranged for rotation about a rotational axis, the portions being coupled by a resiliently flexible coupling portion, which extends radially from said first portion and which is connected to the second portion at a plurality of circumferentially-spaced locations disposed radially outwardly of the first portion.

In use, the first and second portions of the coupling (or vice-versa) can be respectively connected to the floor-engaging tool and the drive motor of a floor treatment appliance, so that when a rotational force is applied by the motor to rotate the first portion about the rotational axis, the force is transmitted by the resiliently flexible coupling portion to correspondingly rotate the tool connected to the second portion.

The resiliently flexible coupling portion allows a small degree of relative rotational displacement between the first and second portions, thereby dampening the effects of any shocks caused when the rotation of the tool is hindered. The resiliently flexible coupling portion also allows the rotational axes of the first and second portions to become misaligned, either into parallel or intersecting orientations, thereby dampening out-of-balance conditions and allowing the tool to rotate in a plane which is inclined relative to normal.

Preferably the resiliently flexible coupling portion comprises a disc, which is preferably formed of an elastomeric material, the centre and periphery of the disc being respectively coupled to the first and second portions of the coupling.

Preferably the resiliently flexible coupling portion extends across an opening in the second portion of the coupling, normal to the rotational axis thereof, the first portion being axially displaceable of the opening.

Preferably means are provided to limit the relative axial displacement of the first and second portions of the coupling.

Preferably means are provided for varying the flexibility and/or resilience of the resiliently flexible coupling portion, the means preferably comprising an element for shortening the radial extent of the resiliently flexible coupling portion.

Preferably, the element comprises an annular member for fitting against the resiliently flexible coupling portion.

Preferably the second portion of the coupling comprises a disc or plate mounted normal to the rotational axis thereof. In use, the brush, pad or other floor-engaging tool of a rotary floor-treatment appliance can be fitted to the disc or plate. Preferably, means are provided on the disc for detachably engaging the floor-engaging tool.

Preferably the first portion comprises a formation for connecting to a complementary formation on the drive shaft of a rotary floor-treatment appliance.

Also in accordance with this invention there is provided a head for a rotary floor-treatment appliance, the head comprising a coupling as hereinbefore described.

Also in accordance with this invention there is provided a rotary floor-treatment appliance having a head comprising a coupling as hereinbefore described.

An embodiment of this invention will now be described by way of an example only and with reference to the accompanying drawings, in which: Figure 1 is a sectional view through a head of a rotary floor-polishing apparatus in accordance with this invention for a rotary floor cleaning appliance; Figure 2 is a bottom view of a coupling disc of the head of Figure 1; Figure 3 is a sectional view along the line A-A of Figure 2; and Figures 4 and 5 are similar views to the view of Figure 1, illustrating how the coupling thereof allows for movement of the polishing tool.

Referring to Figures 1 to 3 of the drawings, there is shown the head of a rotary floor-polishing apparatus comprising a tubular portion 10 which defines an upwardly-facing socket 11 provided with a bayonet connection for detachably engaging the drive shaft (not shown) of the apparatus. In use, the drive shaft is arranged to rotate the first portion around a rotational axis R. The lower end of the tubular first portion 10 is closed by an annular end wall 12 having a depending tubular collar 13 which extends axially from its inner periphery. A depending lip 14 extends axially from the outer periphery of the annular end waIl 12.

The lower end of the collar 13 is connected to the centre of the upper surface of a coupling disc 15 formed of a resiliently flexible elastomeric material having apertures therein. The disc 15 is mounted normal to the rotational axis R and is connected at its outer periphery to the inner periphery of a large annular plate 16. An upstanding flange 17 extends around the upper surface of the coupling disc 15, adjacent the periphery thereof. The flange 17 is disposed slightly radially inwardly of the depending lip 14 on the end wall 12.

The under surface of the large annular plate 16 is covered with a plurality of small hooks 18 which releasably engage the fibres of an annular polishing pad 19. In use, the underside of the pad 19 is placed on the floor to be polished and the apparatus energised to rotate the tool about the rotational axis R. Referring to Figure 3 of the drawings, during polishing the coupling disc 15 can deform to allow the pad 19 to rotate about an axis R', which is inclined relative to the rotational axis R of the drive shaft. The flange 17 and the depending lip 14 are arranged to limit the angle of inclination.

Referring to Figure 4 of the drawings, during polishing the coupling disc 15 can deform to allow axial movement of the pad 19 relative to the drive shaft of the apparatus. Again, the flange 17 and the depending lip 14 are arranged to limit the upwards axial movement of the pad 19. The disc 15 can also deform to allow radial movement of the pad 19 in directions B relative to the drive shaft of the apparatus.

The apertures 20 in the coupling disc 15 allow a small degree of relative rotational movement between the pad 19 and the drive shaft of the apparatus. The degree of this movement depends on the number of apertures 20 and the resilience of the disc 15.

The degree of deformation of the coupling disc 15 can also be adjusted by adding a ring 21 around the collar 13, thereby effectively shortening the radial extent of the unsupported region of the disc 15.

It will be appreciated that the coupling disc 15 dampens vibrations and decouples the user from any forces which may occur as the pad 15 is moved across the floor.

Accordingly, the coupling disc 15 enables the apparatus to operate over a very wide range of speeds without the need to change the type of head. The coupling disc 15 is preferably detachable, so that it can be replaced if it becomes damaged.

Claims (17)

1) A rotary coupling comprising first and second portions arranged for rotation about a rotational axis, the portions being coupled by a resiliently flexible coupling portion, which extends radially from said first portion and which is connected to the second portion at a plurality of circumferentially-spaced locations disposed radially outwardly of the first portion.

2) A rotary coupling as claimed in claim 1, in which the resiliently flexible coupling portion comprises a disc, the centre and periphery of the disc being respectively coupled to the first and second portions of the coupling.

3) A rotary coupling as claimed in claim 2, in which the disc is formed of an elastomeric material.

4) A rotary coupling as claimed in claims 2 or 3, in which the disc is apertured.

5) A rotary coupling as claimed in any preceding claim, in which the resiliently flexible coupling portion extends across an opening in the second portion of the coupling, normal to the rotational axis thereof, the first portion being axially displaceable of the opening.

6) A rotary coupling as claimed in claim 5, in which means are provided to limit the relative axial displacement of the first and second portions of the coupling.

7) A rotary coupling as claimed in any preceding claim, in which means are provided for varying the flexibility and/or resilience of the resiliently flexible coupling portion.

8) A rotary coupling as claimed in claim 7, in which said means for varying the flexibility and/or resilience of the resiliently flexible coupling portion comprises an element for shortening the radial extent of the resiliently flexible coupling portion.

9) A rotary coupling as claimed in claim 7, in which the element comprises an annular member for fitting against the resiliently flexible coupling portion.

10) A rotary coupling as claimed in any preceding claim, in which the second portion of the coupling comprises a disc or plate mounted normal to the rotational axis thereof.

11) A rotary coupling as claimed in claim 10, in which means are provided on the disc for detachably engaging a floor-engaging tool of a rotary floor-treatment appliance.

12) A rotary coupling as claimed in any preceding claim, in which the first portion comprises a formation for connecting to a complementary formation on the drive shaft of a rotary floor-treatment appliance.

13) A rotary coupling substantially as herein described with reference to the accompanying drawings.

14) A head for a rotary floor-treatment appliance, the head comprising a rotary coupling as claimed in any preceding claim.

15) A head for a rotary floor-treatment appliance, the head being substantially as herein described with reference to the accompanying drawings.

16) A rotary floor-treatment appliance having a head comprising a rotary coupling as claimed in claims Ito 13.

17) A rotary floor-treatment appliance, the appliance being substantially as herein described with reference to the accompanying drawings.