GB2413264A

GB2413264A - Floor treatment machine with vibration damping diaphragm

Info

Publication number: GB2413264A
Application number: GB0409123A
Authority: GB
Inventors: Christopher Robert Duncan; Nicholas John Putt
Original assignee: Numatic International Ltd
Current assignee: Numatic International Ltd
Priority date: 2004-04-23
Filing date: 2004-04-23
Publication date: 2005-10-26
Anticipated expiration: 2024-04-23
Also published as: GB2413264B; GB0409123D0

Abstract

This disclosure relates to the field of rotary floor maintenance machines, of a type having a circular or annular rotating treatment head, provided on an underside thereof with a working surface comprising a brush or a polishing pad which rotates parallel and juxtaposed the surface to be cleaned. Treatments may range from polishing, through cleaning, to aggressive treatments such as sanding, grinding, scouring or scarifying. There is disclosed a floor treatment machine comprising a rotatable working head (30) which may be placed on a floor surface to be treated and rotatably driven about an axis perpendicular to the floor surface by a drive head of a motor. The working head is provided on an underside 32 thereof with a working surface to be juxtaposed the floor surface for treatment thereof. The working head is coupled to a drive head via a flexible diaphragm member (20) which permits flexing of the work head relative to the drive head. The diaphragm provides a vibration damping effect when the machine is in use.

Description

Floor Treatment Machine This invention relates to the field of rotary

floor maintenance machines, of a type having a circular or annular rotating treatment head, provided on an underside thereof with a working surface comprising a brush or a polishing pad, which rotates parallel and juxtaposed the surface to be cleaned. Treatments may range from polishing, through cleaning, to aggressive treatments such as sanding, grinding, scouring or scarifying.

Floor treatment machines typically comprise one or more rotatable treatment heads, driven by for example an electric motor. Typical machines are described in WO 92/10128 (Numatic International Limited) and WO 93/14684 (Numatic International Limited). The working surface is formed on an annular ring or circular disc. The working surface may be formed by brushes, which may be soft and pliable, such as for use in polishing, or stiff and wiry such as for use in scarifying or scouring. The working surface alternatively may be formed by sanding or grinding pads, for example formed of abrasive material. The working surface may also be formed by absorbent material such as felt or pads suitable for cleaning with the aid of a cleaning liquid applied to the floor.

Typically the working heads are Remountable for replacement or cleaning.

Examples of known working heads are available from Numatic International Limited, of Chard, Somerset in the United Kingdom. These include accessories for the Twintec _ range and Nuspeed _ ranges of floor treatment machines.

Other manufacturers have similar products that will also be well known to the person skilled in the art.

The treatment machines may be configured to be supported, at least in part, on the working head. There may also be provided rollers, castors or wheels to take a portion of the weight of the machine. The rollers, wheels or castors may be movable, or otherwise arranged, so as to be spaced apart from the floor surface during cleaning. Alternatively, the wheels may engage with the floor to take weight and provide stability for transport across the surface to be treated. The machines are typically provided with a generally upstanding handle portion, which may be provided at an upper end thereof with a handle bar, or hand grips. There may also be provided at this end, machine controls such as an on/off switch and speed control. The handle is typically attached at a lower end thereof to a chassis, monocoque or frame of the machine.

One problem that arises in the operation of such machines is the transmission 2 0 of vibration from the rotating drive and working head to the user through the handle. This may be particularly pronounced over uneven surfaces, or where resonance occurs arising from an interaction between the working head and the surface being cleaned.

Accordingly it is an object of the present invention to provide a treatment machine with reduced vibration transmission to the operator, thereby reducing operator fatigue.

According to one aspect of the invention, there is provided a floor treatment machine comprising a rotatable working head which may be placed on a floor surface to be treated and rotatably driven about an axis perpendicular to the floor surface by a drive head of a motor, the working head being provided on an underside thereof with a working surface to be juxtaposed the floor surface for treatment thereof, wherein the working head is coupled to a drive head via a flexible diaphragm member which permits flexing of the work head relative to the drive head.

The provision of a flexible diaphragm provides more uniform treatment over uneven surfaces. In addition, the diaphragm may provide a significant damping effect which reduces vibration and operator fatigue.

The structural properties of the diaphragm may be tailored to provide the degree of flexing and damping required. For example, the elastic modulus of the material may be varied. A material with a high hysteresis energy loss may be selected to enhance damping of vibrations. The structure of the diaphragm may be altered by providing cut outs, local strengthening or weakening. The number and distribution of cut outs may be altered. "Cut out" refers herein to the end result formation of a hole, rather than necessarily specifying the manner by which the hole is formed. For example the "cut outs" may be moulded or machined. The thickness of the diaphragm material may be altered to adjust the degree to which it may flex.

According to another aspect of the invention, there is provided a flexible diaphragm member for use in the machine described above.

The diaphragm may be in the form of a disc or an annular ring. In one embodiment, the diaphragm is formed with a plurality of circumferentially spaced holes. The holes are preferably uniformly spaced apart. In one configuration, a plurality of radially extending spokes may be defined by the diaphragm portions between the holes.

The holes may each be configured in the general plan form of an isosceles trapezoid, with a long base of each trapezoid further from the centre of the diaphragm than a short base of each trapezoid. The long and short bases may be bowed concentrically.

In a preferred specific embodiment, there are six holes, which define therebetween six spokes of the diaphragm.

The thickness of the diaphragm disc will depend upon the particular applications, but for presently available products of the present applicant, the thickenss may be is in the range of 2mm to 6mm, preferably 3mm to Smm, and most preferably 3.5mm to 4.5mm.

The diaphragm is preferably formed from polymer plastics material. One preferred material is nylon.

The diaphragm is preferably provided with first fixing means, permitting attachment of the diaphragm to the working head. The first fixing means may comprise a plurality of holes formed in the diaphragm, which holes are circumferentially spaced around an outer edge region of the diaphragm.

The diaphragm may be provided with second fixing means permitting attachment of the diaphragm to a drive chuck. The second fixing means may comprise a plurality of holes formed in the diaphragm, which holes are circumferentially spaced around an inner edge region of the diaphragm, the diaphragm having an annular configuration.

According to yet another aspect of the invention there is provided a floor treatment machine as hereinbefore described that is provided with a diaphragm member as hereinbefore described.

According to a further aspect of the invention, there is provided, a working head assembly for a floor treatment machine as hereinbefore described, comprising a drive chuck adapted for Remountable engagement with a drive head of the machine, a diaphragm member as hereinbefore described, which member is attached to the drive chuck, and a working head having an upper surface and a lower working surface, wherein the upper surface is mated to the diaphragm member, and wherein a flexible coupling between the working head and the chuck is provided by a flexible unconstrained web portion of the diaphragm.

Following is a description, by way of example only, and with reference to the 2 0 figures of the drawings, of one method of putting the present invention into effect.

In the drawings: Figures 1A and 1B are exploded perspective views of a working head assembly according to the present invention.

Figure 2 is a plan view of the assembly.

Figure 3 is a cross-sectional view along the line AA shown in figure 2.

Figure 4 is a treatment machine according to the present invention.

In figure I a drive chuck is shown as 10. The drive chuck has a generally annular configuration with an outer cylindrical surface 11 and an inner cylindrical surface 12. The inner cylindrical surface is formed with three inwardly directed raised ridges 13,14 and 15 shown in figure 2. The ridges serve to permit bayonet engagement mounting of the chuck to a drive head of an electric motor drive mechanism (not shown). Bayonet mounts are well known to the person skilled in the art and are not further described in this specification. An underside (not shown) of the chuck is formed with six 2 0 threaded depressions intended to receive threaded fixing bolts.

A diaphragm disc 20 is shown in figure 1. The disc has a generally annular plan form (shown in figure 2), with a central circular cut out core 19. The disc is formed from a plate of flexible moulded nylon material with a thickness of 4 mm. The disc is formed with six circumferentially spaced cut out portions 21.

Each cut out has a generally isosceles trapezoid form. The short edges 22 and long edges 23 of each trapezoid are bowed concentrically as shown in figure 2.

The trapezoids cut outs define therebetween six radially directed spokes 24, each having a width of 40mm. The trapezoids also define a solid outer rim portion 25 of the disc. The rim portion is formed with six circumferentially spaced apart fixing holes 26. Each hole is located at an outer end region of each spoke 24, as shown in figure 2. A corresponding inner end region of each spoke is also formed with six spaced apart fixing holes 27.

A working head 30 is shown in figure 1. The working head has a generally annular configuration. The working head has an upper surface 31 and a lower surface 32. The upper surface is formed with an inner stepped annular depression 33. The depression comprises a first step surface 34, which has an irregular polygonal vertical boundary 35 extending circumferentially. There is a second simple step 36, which serves as a seat for an outer end region of the 2 0 diaphragm seat (as evident from figures 2 and 3). The surface of the second step is provided with six circumferentially space apart threaded depressions 37, which correspond to the location of the fixing holes 26 of the diaphragm disc 20. A final step 40 provides a clearance between a diaphragm portion which overlaps therewith when the diaphragm is seated in the step 36. This clearance permits flexing of the diaphragm that would otherwise be constrained by the work head upper surface.

A lower surface 32 of the work head is formed with a dense distribution of nylon floor treatment bristles 39.

The work head assembly is assembled as follows. The six threaded depressions (not shown) in the chuck underside are aligned with the inner fixing holes 27 on an upper side of the diaphragm disc. Six bolts are then each threaded through a hole and tightened into each depression. The diaphragm disc outer fixing holes 26 are then aligned over the corresponding threaded depressions 37 in the work head second step 36. A bolt is then entered into each hole and tightened into each depression to securely fix the diaphragm to the work head.

The work head 30 may then be attached to a floor-cleaning machine 50 of a type shown in figure 4. The work head is attached by engagement of the inner rim bayonet ridges 13, 14 and IS with corresponding bayonet connectors on a drive head (not shown) of the machine. The machine has a motor housing Sl, two spaced-apart transport roller 52 and an articulated arm 53. The rollers are spaced apart from the floor surface when the work head is located flat on the floor, but engage with the floor when the work head and motor housing assembly are rotated from the floor surface. The machine may thereby be conveniently roller-transported across a surface when not in use. The arm is articulated at a lower end 54 to permit height adjustment. At an upper end of the arm, there is provided a handlebar SS and control panel assembly 56. The operator 57 grasps the handle to direct and move the machine over a surface to be cleaned.

In use, the diaphragm disc provides a structural couple between the drive chuck (and rest of the machine) on the one hand, and the work head on the other. The flexibility of the diaphragm permits flexing of the work head relative to the rest of the machine, in response to movement over uneven cleaning surfaces. The structural properties of the diaphragm disc may be tailored to the particular work head and surface to be cleaned, thereby to provide an appropriate damping or vibration reduction response, or to permit flexing which allows uniform floor treatment of uneven surfaces.

Claims

Claims 1. A floor treatment machine comprising a rotatable working head

which may be placed on a floor surface to be treated and rotatably driven about an axis perpendicular to the floor surface by a drive head of a motor, the working head being provided on an underside thereof with a working surface to be juxtaposed the floor surface for treatment thereof, wherein the working head is coupled to a drive head via a flexible diaphragm member which permits flexing of the work head relative to the drive head.
2. A flexible diaphragm member for use in the machine of claim 1.
3. A diaphragm member as claimed in claim 2 wherein the diaphragm is in the form of a disc or an annular ring.
4. A diaphragm member as claimed in claim 2 or claim 3 and formed with a plurality of circumferentially spaced holes.
S. A diaphragm as claimed in claim 4 wherein the holes are uniformly spaced 2 0 apart.
6. A diaphragm as claimed in claim 4 or claim 5 wherein a plurality of radially extending spokes are defined by the diaphragm portions between the holes.
7. A diaphragm as claimed in claim 6 wherein the holes are each configured in the general plan form of an isosceles trapezoid, with a long base of each trapezoid further from the centre of the diaphragm than a short base of each trapezoid.
8. A diaphragm as claimed in any of claims 4 to 7 wherein there are six holes, which define therebetween six spokes of the diaphragm.
9. A diaphragm as claimed in any of claims 2 to 8 wherein the thickness of the diaphragm disc is in the range of 2mm to 6mm
10. A diaphragm as claimed in claim 9 wherein the thickness of the diaphragm disc is in the range of 3.5mm to 4.5mm.
11. A diaphragm as claimed in any of claims 2 to 10 and formed from polymer plastics material.
12. A diaphragm as claimed in any of claims 2 to 11 and provided with first fixing means, permitting attachment of the diaphragm to the working head.
13. A diaphragm as claimed in claim 12 wherein the first fixing means comprises a plurality of holes formed in the diaphragm, which holes are circumferentially spaced around an outer edge region of the diaphragm.
14. A diaphragm as claimed in any of claims 2 to 12 and provided with second fixing means permitting attachment of the diaphragm to a drive chuck.
IS. A diaphragm as claimed in claim 14 wherein the second fixing means comprises a plurality of holes formed in the diaphragm, which holes are circumferentially spaced around an inner edge region of the diaphragm, the diaphragm having an annular configuration.
16. A floor treatment machine as claimed in claim l that is provided with a diaphragm member as claimed in any of claims 2 to IS.
17. A working head assembly for a floor treatment machine as claimed in claim 1, comprising a drive chuck adapted for Remountable engagement with a drive head of the machine, a diaphragm member according to any of claims 2 to IS, which member is attached to the drive chuck, and a working head having an upper surface and a lower working surface, wherein the upper surface is mated to the diaphragm member, and wherein a flexible coupling between the working head and the chuck is provided by a flexible unconstrained web portion of the diaphragm.
18. A method as claimed in claim 17 wherein the diaphragm selected is a diaphragm according to any of claims 2 to 14.

18. A method of improving a floor treatment machine of a type comprising a rotatable working head which may be placed on a floor surface to be treated and rotatably driven about an axis perpendicular to the floor surface by a drive head of a motor, the working head being provided on an underside thereof with a working surface to be juxtaposed the floor surface for treatment thereof, the method comprising selecting and implementing a flexible diaphragm member to couple the working head to a drive head, thereby to permit flexing of the work head relative to the drive head, the diaphragm being selected on the basis of is structural elastic modulus and/or hysteresis properties to provide a vibration damping effect when the machine is in use.

19. A method as claimed in claim 18 wherein the diaphragm selected is a diaphragm according to any of claims 2 to 15.

Amendments to the Maims have been filed as follows Claims 1. A floor treatment machine comprising a rotatable working head which may be placed on a floor surface to be treated and rotatably driven about an axis perpendicular to the floor surface by a drive head of a motor, the working head being provided on an underside thereof with a working surface to be juxtaposed the floor surface for treatment thereof, the working head being coupled to a drive head via a flexible diaphragm member which permits flexing of the work head relative to the drive head, wherein the flexible diaphragm member is formed with a plurality of circumferentially spaced holes, said holes acting to enhance the flexibility of the diaphragm member.

2. A flexible diaphragm member for use in the machine of claim 1.

3. A diaphragm member as claimed in claim 2 wherein the diaphragm is in the form of a disc or an annular ring.

4. A diaphragm as claimed in claim 2 or claim 3 wherein the holes are uniformly spaced apart.

5. A diaphragm as claimed in any of claims 2 to 4 wherein a plurality of radially extending spokes are defined by the diaphragm portions between the holes.

6. A diaphragm as claimed in claim 5 wherein the holes are each configured in the general plan form of an isosceles trapezoid, with a long base of each trapezoid further from the centre of the diaphragm than a short base of each trapezoid.

7. A diaphragm as claimed in any of claims 2 to 6 wherein there are six holes, which define therebetween six spokes of the diaphragm. ' < 8. A diaphragm as claimed in any of claims 2 to 7 wherein the thickness of the diaphragm disc is in the range of 2mm to 6mm.

9. A diaphragm as claimed in claim 8 wherein the thickness of the diaphragm disc is in the range of 3.5mm to 4.5rnm.

10. A diaphragm as claimed in any of claims 2 to 9 and formed from polymer plastics material.

ill. A diaphragm as claimed in any of claims 2 to 10 and provided with first fixing means, permitting attachment of the diaphragm to the working head.

12. A diaphragm as claimed in claim 11 wherein the first fixing means comprises a plurality of holes formed in the diaphragm, which holes are circumferentially spaced around an outer edge region of the diaphragm.

13. A diaphragm as claimed in any of claims 2 to 12 and provided with second fixing means permitting attachment of the diaphragm to a drive chuck.

14. A diaphragm as claimed in claim 13 wherein the second fixing means . comprises a plurality of holes formed in the diaphragm, which holes are circumferentially spaced around an inner edge region of the diaphragm, the; ' ' diaphragm having an annular configuration.

15. A floor treatment machine as claimed in claim 1 that is provided with a diaphragm member as claimed in any of claims 2 to 14.

16. A working head assembly for a floor treatment machine as claimed in claim 1, comprising a drive chuck adapted for Remountable engagement with a drive 2 0 head of the machine, a diaphragm member according to any of claims 2 to 14, which member is attached to the drive chuck, and a working head having an upper surface and a lower working surface, wherein the upper surface is mated to the diaphragm member, and wherein a flexible coupling between the working head and the chuck is provided by a flexible unconstrained web portion of the diaphragm.

17. A method of improving a floor treatment machine of a type comprising a rotatable working head which may be placed on a floor surface to be treated and rotatably driven about an axis perpendicular to the floor surface by a drive head of a motor, the working head being provided on an underside thereof with a working surface to be juxtaposed the floor surface for treatment thereof, the method comprising selecting and implementing a flexible diaphragm member to couple the working head to a drive head, thereby to permit flexing of the work head relative to the drive head, the diaphragm being selected on the basis of is structural elastic modulus and/or hysteresis properties to provide a vibration damping effect when the machine is in use.