Rotary floor cleaner drive board and rotary cleaner comprising such a drive board

Abstract

A rotary floor cleaner driveboard assembly (112, fig. 1) has a mounting formation for attachment to a rotary drive of a rotary floor cleaner, a cleaning disc (200, fig. 1) comprising a floor-contactin

Description

Technical Field [0001 ] The present invention relatestoa drive board fora rotary floor cleaner, and a cleaner comprising such a drive board. More specifically, the present invention relates to a drive board for a human-propelled floor cleaner such as a scrubber, polisher or burnisher. Background Art

[0002] Various types of rotary floor cleaners are known in the art. They can generally be classified as either larger "walk behind" or "ride on" cleaners, or smaller human-propelled cleaners. The latter tend to have a main body with a cleaning head rotatably mounted thereto. A shaft extends from the body to a handle, allowing the user to push the device along the floor during operation. Controls are typically mounted on the handle. An electric motor drives the cleaning head in rotation, and by friction with the floor surface the head scrubs, polishes or burnishes the surface. The effect achieved depends on the type of head and the speed of rotation, with burnishers operating at the highest speed, and scrubbers at the lowest speed.

[0003] An example human propelled rotary floor cleaner is shown in Figure 1. The rotary floor cleaner 1 00 is shown having a body 102, an upright 104, a handle 1 06, a housing 108, a belt drive 110 and a driveboard 112.

[0004] The body 102 is a generally flat platform extending from a proximal end 114 (proximate the operator in use) to a distal end 11 6. A pair of wheels 11 5 are provided atthe proximal end of the body 102.

[0005] Mounted to the body 102 is the upright 1 04. The upright 104 is a generally elongate member which is rotatable relative to the body 102 about a lateral axis Y, but resiliently urged into an upright position.

[0006] Atthe end of the upright 1 04 opposite to the body 102 there is provided the handle 106, forming a T-shape with the upright and defining two opposing handle bars 118, 120. The handle 106 is provided with on / off lever controls 122a, 122b a height adjustment control 124 and a solution dispenser control 126 for a cleaning solution reservoir (not 31 05 23 shown). In use, the user can grip the handle bars 118, 120 to support and propel the cleaner 1 00 whilst operating the various controls.

[0007] In use, the weight of the cleaner is supported on the rotating drive board, which is in contact with the floor surface being cleaned. Rotation of the drive board at high speed results in relatively low friction between the cleaner and the floor, allowing it to be pushed along. This is shown in Figure 2a.

[0008] When the cleaner is not in use, the wheels 11 5 and the drive board 112 support the cleaner 1 00 together (Figure 2b). The cleaner can be tipped up to bring the drive board out of contact with the floor to move the cleaner or replace the drive board (Figure 2c).

[0009] Referring to Figure 2b, the weight of the cleaner 100 is reacted at a first contact point between the rear of the driveboard 112 and the floor (R1), and between the wheels 11 5 and the floor (R2). Problematically, this causes a torque to be applied between the reaction force R1 and the drive formation of the drive board. Leaving the cleaner 100 in this state for extended periods can cause the drive board to plastically deform and thus develop an eccentricity. This is undesirable in use, because eccentricity in rotating components can cause undesirable oscillation and vibration.

[0010] The applicant has a product known as CentreFlex (RTM), in which a degree of flexibility is built into the drive board. The flexibility is provided by an annular flexion ring, and is intended to maintain even contact between the cleaning surface and the floor even with movement of the cleaner 100 as a whole. Problematically, the CentreFlex (TM) technology is susceptible to the aforementioned problem, as the flexion ring can be plastically deformed. [0011 ] It is an aim of the present invention to overcome, or at least mitigate, this problem. Summary of Invention

[0012] According to a first aspect of the present invention there is provided a rotary floor cleaner driveboard assembly comprising: a mounting formation for attachment to a rotary drive of a rotary floor cleaner; a cleaning disc comprising a floor-contacting cleaning material; a flex ring connecting the mounting formation to the cleaning disc, the flex ring attached to the mounting formation at a first, inner radius and to the cleaning disc at a second, outer, radius; and, a resilient, compressible structure between the flex ring and the cleaning disc.

[0013] Advantageously, the compressible structure can be configured to take up a lot of the deformation of the driveboard which occurs in the aforementioned state. In particular, it reduces the level of strain on the flex ring, keeping the stress it experiences in the elastic zone. This reduces the likelihood of permanent, plastic deformation.

[0014] Preferably the compressible structure is annular.

[0015] Preferably the compressible structure is a gasket.

[0016] Preferably the compressible structure comprises an elastomeric material. [001 7] Preferably the compressible structure comprises a cellular material.

[0018] Preferably the compressible structure comprises one or more springs.

[0019] Preferably the compressible structure is provided within a recess of the cleaning disc.

[0020] Preferably the compressible structure is provided within a recess of the flex ring.

[0021] Preferably the compressible structure is provided within a space bounded by the cleaning disc on a first and a second side, and the flex ring on a third and a fourth side.

[0022] Preferably the compressible gasket is quadrilateral in cross section.

[0023] Preferably there are provided mechanical fasteners attaching the flex ring to the cleaning disc, wherein the fasteners pass through the compressible structure.

[0024] Preferably the limit of insertion of the fasteners into the cleaning disc is limited.

[0025] Preferably spacers are provided between the cleaning disc and the fastener heads to limit the insertion of the fasteners into the cleaning disc.

[0026] Preferably the flex ring comprises openings dimensioned to slide over the spacers.

[0027] The invention also provides a rotary floor cleaner comprising a driveboard assembly according to the first aspect.

[0028] Preferably the cleaner comprises a main body, wherein the driveboard assembly is mounted at a first end thereof, and at least one floor contacting support member is mounted at a second end thereof such that at rest, the cleaner is supported on the cleaning disc and the at least one floor contacting member. Brief Description of Drawings

[0029] An embodiment of the present invention will now be described with reference to the following figure in which: FIGURE 1 is a perspective view of a rotary floor cleaner; FIGURES 2a to 2c are side views of the rotary cleaner of Figure 1 in various conditions; and. FIGURE 3 is a perspective view of a driveboard assembly in accordance with the present invention FIGURE 4 is an exploded view of the driveboard assembly of Figure 3, FIGURE 5 is a plan view of the driveboard assembly of Figure 3, FIGURES 5a to 5b are section views through a-a and b-b in Figure 5; FIGURE 6a is a detail section view of area VI in Figure 5a in an undeformed state; FIGURE 6a is a detail section view of area VI in Figure 5a in a deformed state; FIGURE 7a is a detail section view of area VII in Figure 5b in an undeformed state; and, FIGURE 7b is a detail section view of area VII in Figure 5b in a deformed state. Description of the first embodiment

[0030] Referring to Figures 3 to 5b, a driveboard 112 according to the present invention is shown. Referring to Figure 4, the driveboard 112 comprises a cleaning disc 200, a compression gasket 202, a flex ring 204, spacers 205, a frame 206 and a catch 208. A first set of screws 210, a second set of screws 212 and a third set of screws 214 are provided. [0031 ] The cleaning disc 200 is annular in shape, having an outer perimeter 216 and an inner perimeter 218 defining an opening 220. The disc 200 has a first, upper surface 222 and a second, lower, surface 224 to which a cleaning material (not shown) is affixed. An indented shoulder 226 is formed where the inner perimeter 218 and upper surface 222 meet. The disc 200 is formed from a stiff plastics material.

[0032] The compression gasket 202 is annular in shape, and formed from a compressible, elastically deformable material such as an elastomer. It may be homogenous, or e.g., a foamed material.

[0033] The flex ring 204 is also annular in shape, having an outer perimeter 228 and an inner perimeter 230 defining an opening 232. The ring 214 has a first, upper surface 234 and a second, lower, surface 236. Referring to Figure 6a, the ring 214 is formed from two annular portions - an outer annular portion 238 and an inner annular portion 240 which are offset and joined by a cylindrical shoulder 242.

[0034] The frame 206 is constructed from a moulded plastic material and is generally discshaped having a plurality of first bosses 244 at a first, inner radius and a plurality of second bosses 246 at a second, outer radius. The bosses 244, 246 project in the same axial direction. The bosses 244, 246 also alternate in a circumferential sense (i.e. each inner boss 244 is spaced midway between outer bosses and vice versa).

[0035] The catch 208 is a cast metal material. It is annular in shape defining a mounting formation 248 on a first side, and a plurality of screw openings 250 therethrough. Assembly

[0036] The components are stacked as shown in Figure 4. The catch 208 and frame 206 are attached with screws 214 through the openings 250 which engage with the first bosses 244.

[0037] The compression gasket 202 is placed on the cleaning disc 200 in the indentation caused by the shoulder 226. The flex ring 204 is then placed onto the gasket 202 such that the gasket 202 is sandwiched between the cleaning disc 200 and the flex ring 204.

[0038] The flex ring 204 is then attached to the cleaning disc with screws 212. The screws are configured such that they maintain a distance between the flex ring 204 and disc 200 without compressing the gasket 202 in a neutral, unloaded state (Figure 5b). This is done by provision of the spacers 205. Referring to Figure 7a, the spacers 205 are arranged between the upper surface of the disc 200 and the underside of the head of the screws 212 so as to limit the insertion of the latter. The opening in the flex ring 204 is provided so as to be wide enough to accommodate the spacers 205, along the flex ring to move relative thereto.

[0039] The flex ring 204 is then fastened to the frame 206 with screws 21 0 to bosses 246. It will be noted that the screws 210, 212 are positioned at different radii- the screws 210 are on a smaller radius compared to screws 212, therefore allowing the annular part of the flex ring (the flexion zone FZ) to deform under bending (Fig. 5b). Use

[0040] Without the gasket 202, the displacement (rotation) of the disc 200 relative to the catch 208 under force F1 (Figures 2b &5b) deforms the flexion zone FZ of the flex disc 204. [0041 ] The drive board 112 deforms by a fixed distance in this situation- it typically "bottoms out" when the disc 200 contacts the machine (Figure 2b). Therefore it is a "fixed displacement" problem. The present invention uses the gasket 202, which is compressible, resilient but less stiff than the flex ring 204 to absorb part of that displacement. Comparing Figures 6a / 7a (no load) and 6b / 7b (loaded per Figure 2b), it can be seen that the gasket 202 has compressed between the flex ring 204 and the disc 200, reducing the degree of flexion required from the flex ring 204. This in turn means that the flex ring 204 rests further into its elastic region (away from its yield strength at the elastic-plastic boundary) and as such is less likely to undergo plastic deformation. Variations

[0042] Other types of compressible, resilient materials may be used for the gasket 202. Alternatively, deformable resilient structures such as springs may be used instead of, or as well as the gasket. In one embodiment, a plurality of compression springs may be placed around the perimeter.

Claims

31 05 231. A rotary floor cleaner driveboard assembly comprising:a mounting formation for attachment to a rotary drive of a rotary floor cleaner;a cleaning disc comprising a floor-contacting cleaning material;a flex ring connecting the mounting formation to the cleaning disc, the flex ring attached to the mounting formation at a first, inner radius and to the cleaning disc at a second, outer, radius; and,a resilient, compressible structure between the flex ring and the cleaning disc.

2. A rotary floor cleaner driveboard assembly according to claim 1, wherein the compressible structure is annular.

3. A rotary floor cleaner driveboard assembly according to claim 2, wherein the compressible structure is a gasket.

4. A rotaryfloor cleaner driveboard assembly accordingtoany of claims 1 to3, wherein the compressible structure comprises an elastomeric material.

5. A rotaryfloor cleaner driveboard assembly accordingtoany of claims 1 to4, wherein the compressible structure comprises a cellular material.

6. A rotaryfloor cleaner driveboard assembly accordingtoany of claims 1 to5, wherein the compressible structure comprises one or more springs.

7. A rotary floor cleaner driveboard assembly according to any preceding claim, wherein the compressible structure is provided within a recess of the cleaning disc.

8. A rotary floor cleaner driveboard assembly according to any preceding claim, wherein the compressible structure is provided within a recess of the flex ring.

9. A rotary floor cleaner driveboard assembly according to claim 8, dependent on claim 6, wherein the compressible structure is provided within a space bounded by the cleaning disc on a first and a second side, and the flex ring on a third and a fourth side.

10. A rotary floor cleaner driveboard assembly according to claim 3, wherein the compressible gasket is quadrilateral in cross section.31 05 2311. A rotary floor cleaner driveboard assembly according to any preceding claim, comprising mechanical fasteners attaching the flex ring to the cleaning disc, wherein the fasteners pass through the compressible structure.

12. A rotary floor cleaner driveboard assembly according to claim 11, wherein the limit of insertion of the fasteners into the cleaning disc is limited.

13. A rotary floor cleaner driveboard assembly according to claim 12, wherein spacers are provided between the cleaning disc and the fastener heads to limit the insertion of the fasteners into the cleaning disc.

14. A rotary floor cleaner driveboard assembly according to claim 13, wherein the flex ring comprises openings dimensioned to slide over the spacers.

15. A rotary floor cleaner driveboard assembly according to any preceding claim, wherein the compressible structure is sandwiched between the cleaning disc and the flex ring.

16. A rotary floor cleaner comprising a driveboard assembly according to any preceding claim.1 7. A rotary floor cleaner according to claim 1 6, comprising a main body, wherein the driveboard assembly is mounted at a first end thereof, and at least one floor contacting support member is mounted at a second end thereof such that at rest, the cleaner is supported on the cleaning disc and the at least one floor contacting member.

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