GB2191081A

GB2191081A - Floor treatment machine

Info

Publication number: GB2191081A
Application number: GB08711939A
Authority: GB
Inventors: William Henry Gilbert
Original assignee: BTR PLC
Current assignee: BTR PLC
Priority date: 1986-06-03
Filing date: 1987-05-20
Publication date: 1987-12-09
Also published as: GB8711939D0; GB2191081B

Abstract

A floor treatment machine e.g. floor polisher, scrubber, or sanding machine comprises a floor treatment element 26 comprising a drive back 28, to which a pad 40 may be releasably secured by gripping element 42, and a carrier 10 therefore, said carrier comprising a boss 14 provided with drive pins 16 which engage in bushes 32 in the drive back, the coupling arrangement being such that drive is transmitted from shaft 11 to the floor treatment element whilst permitting free movement of the latter relative to the carrier in a direction towards or away from the floor. The carrier is supported above the floor by a supporting structure (not shown). The coupling arrangement may be such as to permit limited tilting movement of the drive back. Either a rotary or reciprocating movement may be imparted to the floor treatment element. <IMAGE>

Description

SPECIFICATION Floor treatment device This invention relates to floortreatment devices, such as electrically powered floor polishers, scrubbers, sanding machines, etc. In such machines it is common practice for a floor treatment element, e.g. an annularordisc-shaped polishing pad, to be attached by a suitable boss at the lower end of a vertical shaft of an electric motor mounted in a carrier housing having a handleforcontrol by the operator.

It is a problem in the use of machines of this kind thatthe treatment element may not easily accommodate itselfto an uneven floor and maintain auniform pressureontheflooroverthewhole surface of the treatment element when the machine tilts as a result of the unevenness of the floor, or underforces exerted by the operator.

One object of the invention is to provide a floor treatment device which enables a more uniform pressure to be exerted and maintained between its floor treatment element and a floor.

According to the invention, a floor treatment device comprises a carrier for a floortreatment element, drive means connected to the carrierto drive the carrier and hence a floor treatment element so as to effect rubbing movement of the floor treatment element in engagement with a floor, and a floating coupling device arranged to be interposed between thefloortreatment element and the carrier so as to transmit drive from the carrier to the floor treatment element and to permit free movement of the floortreatment element relative to the carrier in a direction towards or away from the floor, and support means independent of the floating coupling means arranged to hold the carrier above a floor surface with a floortreatment element in engagement with the floor, wherein the carrier comprises a drive boss and the floating coupling device comprises a plurality of normally vertical drive pins associated with the drive boss and a drive backto which a floor treatment element may be releasably secured, the drive pins being secured to the drive boss and engaging the drive back via sockets formed therein so asto permitvertical movement and tilting of the drive back thereon.

The drive means may be fully rotary, or a reciprocating movement may be imparted to the floor treatment element.

One embodiment ofthe invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure lisaplanviewshowingpartofafloor treatment element, viewed from above, Figure2 is a vertical section taken on the line Il-Il of Figure 1 showing the floortreatment element and part of its associated drive structure, Figure 3 is a similar viewto Figure 2 showing an alternative drive structure, Figure 4 is a plan viewof partof a floorcleaning machine in accordance with the invention, Figure 5 is a vertical cross-section, taken on the line A-A, of part of the machine shown in Figure 4, and Figure 6is a scrap vertical cross-section on the line B-B.

Figures 1 - 3 ofthe drawings illustrate part of a floor cleaning machine. Features which are not shown include support means comprising a housing and an electric motor mounted vertically in the housing, a handle attached to the housing, and an electrical supplycableforthe motor. The housing is arranged to supportthe structure illustrated in the drawings and the support meansfurthercomprises suitable castors attached to the housing to enable the housing to move easily over a floor.

As shown in Figure 2, a carrier 10 comprises a drive shaft 11 of the associated electric motor, a drive boss 14 keyed to the shaft 11, and four vertical drive pins 16. The drive pins 16 each comprise a bolt 18 screwed into a threaded hole 19 in the drive box 14, and a steel sleeve 21 around the bolt 18 clamped between a washer 22 and the drive boss 14.

The arrangement is such that the carrier 10 is supported by its associated housing (not shown) at a fixed distance above a floor 24, and is rotatable about a vertical axis by the electric motor via the drive shaft 11.

Afloortreatment element 26 comprises a "drive back" 28 which is a rigid disc made from plywood or other suitable material. Four holes 30 of stepped diameter are formed in the drive back 28 to receive flanged bushes 32 of hard rubber to form sockets through which the drive pins 16 pass with clearances such that the inside diameters of the bushes are about 0.2 millimetres greaterthan the outside diameters of the pins. The bushes 32 are retained in the drive back 28 by an annular steel plate 34 secured by six screws 35.

The drive pins 16 together with the drjve back 28 constitute a floating coupling device which transmits drive from the shaft 11 to anyfloortreatment element which may be secured to the drive backto float freely in the vertical direction and to tilt, if necessary,through asmall angle of, say, 10', according to the size of the clearances between the drive pins 16 and the bushes 32 and the axial length ofthe bushes 32.

in orderto secure polishing pads orotherfloor treatment elements to the drive back 28 any conventional means may be used. In Figure 2 an annular polishing pad 40 is releasablysecured via an annular "Instalok" (registered trade mark) gripping element 42 to a plastics foam annulus 44 which is itself permanently secured by an adhesive to the lower side of the drive back 28.

In operation,the polishing pad 40,which may be about 430 millimetres in diameter, is rotated at a speed of approximately 1500 revolutions per minute.

Any local variation inthefloorsurfaceasthe machine is pushed by the operator across it may cause the polishing pad 40 to rise orfall relative to the carrier 10 but the vertical load applied to the pad/floor interface is determined almost entirely by the weight of the floating parts, i.e. the drive back 28, foam annulus 44, gripping element 42 and pad 40.

Thus a substantially constant vertical load is applied and byvirtue oftheclearance around the drive pins 16 some degree of tilt can also be accommodated. As a result, substantially improved uniformity in cleaning or polishing operations can be achieved.

In orderto provide greater flexibility to accommodate local floor surface variations, the plywood drive back of the floor treatment element illustrated in Figure 2 may be replaced by a relatively thin drive back e g of strong but flexible plastics material such as ABS. The alternativefloortreatment element 56 shown in Figure3 is mounted on a drive boss 58 as described above, by means offourdrive pins 59 secured to the drive boss 56 and passing through hard rubber bushes 61, but the plywood drive back 28 is reduced to a central support disc 63 and an ABS moulding forms a drive back 65 having a thickness of 3 millimetres to enable it to flex relatively easily.

The drive back 65 is secured by screws (not shown) to the plywood support disc 63, thus fulfilling the additional function of retaining the rubber bushes 61. The central portion ofthe drive back provides a recess 68 into which the support disc 63 is fitted.

The remaining parts ofthefloortreatment element, comprising a plastics foam annulus 70, a gripping element72 and a polishing pad 74 are similarto those of the embodiment described with reference to Figures 1 and 2. A dust coverforthe machine is indicated at 78, part of this item being shown on the left hand side ofthe drawing only.

Figures 4-6 are included to show in more detail the the general support structure of a cleaning machine incorporating a drive structure ofthe kind shown in Figure3.

With reference to Figure 4 and Figure 5, a metal housing 101 supports an electric motor (not shown) from which a drive shaft 103 projects downwardly through an aperture 104. Adrive boss 105 is secured to the shaft 103 by keys 107 and a grub screw (not shown) in a radial threaded hole 108.

Fourvertical drive pins 110 are provided, each pin comprising a steel bolt 111 screwed into a threaded hole (not shown) in the boss 105, a steel sleeve 112 around the bolt 110 and a low-friction plastics sleeve 113 around the steel sleeve 112 being clamped between a washer 1 14 and the boss 105. The drive back 120, plastics foam annulus 121, gripping element 124 and polishing pad 126 are similarto those described with reference to Figure 3.

Figure 4 shows the support structure in plan.

The support structure, which carries the housing and carrierweightindependentlyofthefloating coupling and floortreatment element, comprises two rear wheels 130,131 freely rotatably mounted on a fixed axle 133 and two castor assemblies 135,136 mounted on brackets 137, 138 respectively. The detail elevation of a castor assembly shown in Figure 6 illustrates the operation of the castor assemblies (togetherwith the wheels 130, 131) to support the housing 101 atafixed height above a floor 139, a freely rotatable castor wheel 140 being carried on a swivel mounting 142 secured to the bracket 137 in conventional manner.

The housing 101 has a rubber peripheral ring 150 which is grooved to enable a flexible plastics skirtto be flexibly attached to the housing by means of a fabric collar 154 secured into a groove of the ring 150 by a retaining wire.

Adustshield 160 is secured into the housing 101, which also contains a compartment 162 for electrical components 163,164. A multiple-position adjustable handle support is indicated by reference numeral 170, and a connection 180 is provided forthe application of vacuum to the inside of the skirt if required.

Claims

1. Afloortreatment device comprising a carrier for a floor treatment element, drive means connected to the carrier to drive the carrier and hence a floor treatment element so asto effect rubbing movement of the floor treatment element in engagement with a floor, and a floating coupling device arranged to be interposed between the floor treatment element and the carrier so as to transmit drive from the carrier to the floor treatment element and to permit free movement of the floor treatment element relative to the carrier in a direction towards or away from the floor, and support means independent ofthefloating coupling means arranged to hold the carrier above a floor surface with a floortreatment element in engagement with the floor, wherein the carrier comprises a drive boss and the floating coupling device comprises a plurality of normally vertical drive pins associated with the drive boss and a drive back to which a floor treatment element may be releasably secu red, the drive pins being secured to the drive boss and engaging the drive back via sockets formed therein so as to permit vertical movement and tilting of the drive backthereon.

2. A floor treatment device according to Claim 1 wherein the sockets comprise hard rubber bushes.

3. Afloortreatment device according to Claim 1 or Claim 2 wherein the drive pins each comprise a bolt or screw engaging the drive boss and a sleeve surrounding the bolt or screw to engage the drive back.

4. A floor treatment device according to any of Claims 1-3 wherein the drive pins each comprise a sleeve of low-friction plastics material.

5. A floor treatment device according to any of Claims 1-4 wherein four drive members are provided.

6. Afloortreatment device according to any of Claims 1-5 wherein the drive back is formed from plywood.

7. A floor treatment device according to any of Claims 1-6 wherein the drive back is formed from a plastics material.

8. Afloortreatment device according to Claim 9 wherein the drive back is recessed in its central portion to accommodate a support disc.

9. A floor treatment device constructed and arranged substantially as described and illustrated in Figures 1 and 2 or Figure 3 or Figures 4-6 ofthe accompanying drawings.