GB2232367A

GB2232367A - Surface preparation machine

Info

Publication number: GB2232367A
Application number: GB9003456A
Authority: GB
Inventors: Geoffrey Riddell
Original assignee: LONDON GENERAL SALES Ltd
Current assignee: LONDON GENERAL SALES Ltd
Priority date: 1989-06-08
Filing date: 1990-02-15
Publication date: 1990-12-12
Also published as: GB9003456D0; GB8913257D0

Abstract

A machine suitable for use to prepare the surface of a floor, roof, wall or the like, for example by abrading, grinding or polishing, comprises a chassis 10 supported upon at least three, preferably four, wheels or rollers 21, a surface preparation device such as an abrasive disc mounted upon the chassis for rotation about an axis generally perpendicular to the common plane of the peripheries of the wheels or rollers, and adjustment means to vary the distance apart of the chassis and the wheels or rollers in a direction parallel to that axis of rotation. <IMAGE>

Description

Surface Preparation Machine The present invention is concerned with machines which are used to prepare the surface of floors, roofs, walls and the like, for example by abrading, grinding or polishing.

Machines of the foregoing type may be provided with a rotary disc having a surface which is designed to traverse the floor or the like to be prepared, the surface of the disc being designed to abrade or polish the floor as desired. In particular where the requirement is to remove a layer of paint or of solid contamination from the floor, the machine may be a substantial one applying a relatively powerful treatment to the floor surface and its use may entail a significant amount of effort on the part of the operator. However proper operation of an abrasive machine of this type requires that the abrasive surface be held truly parallel to the surface being treated and this requirement is not readily met by a manually-supported machine, especially as the operator tires after operating the machine for other than a short period. Prior such machines have tended to follow the contours of the floor rather than produce an overall level surface.The e wear on the abrasive surface of the rotary disc increases as the operator tires.

With such disadvantages of prior surface preparation machines in mind, an object of the present invention is to provide an improved machine for this purpose, in particular such a machine in which the operating disc or the like may be kept level at a predetermined distance above the surface being treated, independently of the tiredness of the operator.

The improved surface preparation machine according to the present invention comprises a chassis supported upon at least three wheels or rollers, a surface preparation device mounted upon the chassis for rotation about an axis generally perpendicular to the common plane of the peripheries of the wheels or rollers, and adjustment means to vary the distance apart of the chassis and the wheels or rollers in a direction parallel to said axis of rotation.

As may readily be understood, the wheels and chassis hold the surface preparation device, for example an abrasive disc, level throughout its use and the position of the device relative to the surface being prepared may be changed by operation of the adjustment means.

As stated, the chassis is supported upon at least three wheels or rollers. In a greatly preferred form of the invention, the chassis is supported upon four wheels, for example disposed in the general regions of the respective corners of a generally rectangular base plate. The wheels or rollers are nrunted so as to permit their being moved towards and away fran the chassis.

Preferably such movement is of all the wheels at once. Thus, for example, the wheels may be mounted upon a common support which itself is nsvable towards and away from the chassis.

However, in a preferred form of the invention, the wheels are mounted in two pairs upon two axles, by means of which their position relative to the chassis may be varied. In a particularly preferred form, the wheels are mounted so as to be free to rotate upon a pair of cranked axles, adjustment of the position of the wheels being achieved by rotation of the axles.

The adjustment means nay advantageously comprise a control cable by nsans of which the relative positiaisof the chassis and wheels may be varied from a position on the machine remote fran the wheels, for example on the handle by which the machine is pushed and steered. For example such a cable may extend from axles supporting the wheels to an operating lever or rotary control upon the handle. Less desirably, the wheels may be adjusted, together or individually, by adjustment means operated from a position in the region of the wheels.In another less preferred form of the invention, the adjustment means comprises one or more levers and one or more rigid links, connected in series between the wheels and the machine handle.

The surface preparation device mounted upon the machine chassis may take several possible forms. Thus it may comprise a rigid flat disc having an abrasive surface, a flexible disc having a smooth surface for polishing purposes, or a generally concave cutter member having a plurality of abrasive tips disposed in the region of its periphery. In another form, the device may be a toothed blade. The device is preferably electrically driven, by a motor mounted upon the chassis.

Preferably some form of shock-absorbing mEans is disposed between the wheels or rollers and the chassis.

For example shodk-absorbing rubber bushes may be provided for this purpose. In a preferred form of the invention, the wheels are adjustably mounted upon a base plate and the chassis is supported by rubber shock#absorbers upon the base plate.

Since the operation of an abrasive machine to remove deposits or one or more layers fron a floor or other surface inevitably generates a large ardent of dust, vacuum means should be provided in most situations, to assist in the removal of such dust. Thus a flexible or rigid vacuum tube may be mounted upon the machine, extending from a hood over the abrasive device to a convenient dust collection point on or off the machine. Such dust extraction may be greatly assisted by the design of the abrasive operating head. In one specific embodiment of the machine according to the invention, described below with reference to the accompanying drawings, the abrasive device takes the form of a generally concave cutter disc which has teeth or diamond cut tips distributed about its periphery and a number of apertures distributed over its surface to permit dust to be withdrawn through the cutter disc.

It is advantageous for the cowling or hood which covers the abrasive operating head in many forms of the invention to be provided with a circumferential skirt which projects towards the surface being treated and helps to sustain the vacuum which withdraws the dust produced by the machine.

Thus some prior machines of this general type have been provided with such a skirt formed of rubber. A disadvantage of such a rubber skirt is that it may have the effect of forming or sustaining a vacuum bond between the hood and the ground. According to one feature of the present invention, the hood may be provided with a circumferential skirt in the form of a resilient or cushioned brush, which gives the benefits of such a skirt without the foregoing disadvantage of a rubber skirt.

If desired, the machine according to the present invention may be so constructed that the surface preparation device may be detachable, together with any hood, from the chassis to enable the device to be used hand-held to prepare small surface areas requiring close careful treatment.

The invention will now be further described with reference to the accompanying drawings, which illustrate, by way of example only, one preferred embcdinrnt of the surface preparation machine according to the present invention and wherein; Fig. 1 is a perspective view of the machine groan one side; Fig. 2 is a side elevation, to a larger scale and partly in section, of the chassis assembly and operating head of the machine; and Fig. 3 is a plan view of the chassis assembly shown in Fig. 2.

The illustrated machine is constructed upon a chassis 10 supported upon cylindrical rubber shock-absorbers 11 mounted upon a base plate 12. The chassis 10 supports a rotary cutter disc 13, driven via a drive shaft 14 and gears 15 by an electric motor 16 also mDunted upon the chassis. The cutter disc 13 is covered by a hood 17, the interior of which is linked by a flexible vacuum tube 18 (Fig. 2) to a source of vacuum and associated dust collector (not shown in the drawings).

Extending downwardly from the periphery of the hood 17 is a skirt 19 formed of close-set bristles. The frustoconical surface of the cutter disc 13 is penetrated by a number of apertures 20, uniformly distributed over that surface.

The whole assembly is supported upon wheels 21 mounted upon the base plate 12, such that the machine may be moved on the wheels over the surface 22 to be abraded. As the cutter disc 13 is rotated, blades 23 on the periphery of the disc engage the surface 22 and remove material as a dust fran that surface. The dust passes through the apertures 20 into the hood 17 and thence, via the vacuum tube 18, to the dust collector. The e skirt 19 assists in maintaining the vacuum within the hood but has sufficient capacity to pass air and sufficient fleiibility to prevent the hood becoming held to the surface 22 by the vacuum within the hood.

Operation of the m tor 16 and the cutter disc 13 is by means of a lever 24 mounted at the upper end of the machine handle 25 and linked to the motor by a cable 26. The cutter disc remains truly level throughout by virtue of the wheels 21.

The wheels 21 are mounted, as shewn in Fig. 3, upon a pair of cranked axles 27. The wheels are free to rotate independently of the axles. The axles 27 are in turn mounted upon the base plate 12 by means of axle bushes 28. Pins 29 link the two axles to the opposite ends of a connecting rod 30, by means of which the axles may be rotated through a limited angle within the axle bushes 28. eDvement of the rod 30 in the direction of its length is effected, via a cable 31, by an adjustment knob 32 on the handle 25.

Thus, by rotation of the knob 32, the wheels 21 may be swung from the position 33 shown in full line in Fig. 2, anticlockwise into the broken-line position 34. In this way, the height of the base plate 12 above the surface 22, and thus the height of the chassis 10 and in turn of the cutter disc 13 above the surface 22, may be varied finely by rotation of the knob 32, the whole assembly remaining level throughout the adjustment, in spite of any small-scale irregularities in the floor surface.

In experimental operation of the illustrated machine, it has proved to be able to remove solid contamination from horizontal floor or roof surfaces of concrete, steel or timber. Some 99% of the dust produced is successfully extracted via the vacuum system and, at the same time, the treated surface is left in a satisfactory condition for any required further treatment. With the addition of a toothed blade, the machine may be used to reprove such surface layers as homogeneous vinyls, rubber, cushion vinyl and asbestos tiles in an essentially dust-free operation.

Claims

1. A surface preparation machine comprising a chassis supported upon at least three wheels or rollers, a surface preparation device mounted upon the chassis for rotation about an axis generally perpendicular to the carrion plane of the peripheries of the wheels or rollers, and adjustment means to vary the distance apart of the chassis and the wheels or rollers in a direction parallel to said axis of rotation.

2. A surface preparation machine as claimed in claim 1, wherein the chassis is supported upon four wheels.

3. A surface preparation machine as claimed in claim 2, wherein the wheels are mounted upon a generally rectangular base plate.

4. A surface preparation machine as claimed in claim 3, wherein the chassis is supported upon rubber shockabsorbers on said base plate.

5. A surface preparation machine as claimed in any of the preceding claims, wherein the wheels or rollers are mounted so as to be all adjustable together relative to the chassis.

6. A surface preparation machine as claimed in any of claims 2 to 4, wherein the wheels are mounted in two pairs upon two axles, by means of which their position relative to the chassis may be varied.

7. A surface preparation machine as claimed in claim 6, wherein said wheels are ItOunted so as to be free to rotate upon a pair of cranked axles and adjustment of the position of the wheels relative to the chassis is achieved by rotation of the axles.

8. A surface preparation machine as claimed in any of the preceding claims, wherein the adjustment means comprises a control cable operable from the handle of the machine.

9. A surface preparation machine as claimed in any of the preceding claims, wherein the surface preparation device comprises a rigid flat disc having an abrasive surface, a flexible disc having a smooth surface, a generally concave cutter member having a plurality of abrasive tips disposed in the region of its periphery, or a toothed blade.

10. A surface preparation machine as claimed in claim 9, wherein the surface preparation device is a generally concave cutter nErtr having teeth or diartond cut tips distributed about its periphery and a number of apertures distributed over its surface.

11. A surface preparation machine as claimed in any of the preceding claims, having a hood covering the surface preparation device.

12. A surface preparation machine as claimed in claim 11, wherein the hood is provided with a circumferential skirt in the form of a resilient or cushioned brush.

13. A surface preparation machine as claimed in claim 11 or 12, having a vacuum tube upon the machine extending fran the hood to a dust oollection point.

14. A surface preparation machine as claimed in any of the preceding claims, wherein the surface preparation device is detachable, together with any hood, from the chassis.

15. A surface preparation machine substantially as hereinbefore described with reference to, and as illustrated in, the accampanying drawings.