ROLLERS FOR VACUUM CLEANERS

Abstract

A roller for a vacuum cleaner comprises: an interior roller body which comprises a resiliently deformable region; and an exterior abrasion-resistant skin which surrounds the interior roller body.

Claims

1. A roller for a vacuum cleaner, the roller comprising: an interior roller body which comprises a resiliently deformable region; and an exterior abrasion-resistant skin which surrounds the interior roller body, wherein the exterior abrasion-resistant skin is formed from a non-porous material and exhibits an abrasion loss, during abrasion resistance testing according to DIN 53516, of no greater than 150 mm.sup.3.

2. The roller according to claim 1, wherein the resiliently deformable region is a resiliently compressible region.

3. (canceled)

4. The roller according to claim 1, wherein the exterior abrasion-resistant skin exhibits an abrasion loss, during abrasion resistance testing according to DIN 53516, from 15 mm.sup.3 to 150 mm.sup.3.

5. The roller according to claim 1, wherein the exterior abrasion-resistant skin is formed from an abrasion-resistant polymeric material.

6. The roller according to claim 5, wherein the exterior abrasion-resistant skin is formed from thermoplastic polyurethane.

7. The roller according to claim 1, wherein the exterior abrasion-resistant skin has: (a) a Shore A hardness greater than 40; (b) a tensile strength of greater than 10 MPa; (c) an elongation to failure greater than 200%; and/or (d) a tear resistance greater than 20 kN/m.

8. The roller according to claim 1, wherein the exterior abrasion-resistant skin is adhered to the interior roller body.

9. The roller according to claim 1, wherein the exterior abrasion-resistant skin has a thickness from 100 μm to 400 μm.

10. (canceled)

11. The roller according to claim 1, wherein the resiliently deformable region and the exterior abrasion-resistant skin are chemically distinct from one another.

12. The roller according to claim 1, wherein the resiliently deformable region has a Shore A hardness no greater than 20 and/or a tear resistance of less than 10 kN/m.

13. The roller according to claim 1, wherein the resiliently deformable region is porous.

14. The roller according to claim 13, wherein the porosity, pore size and/or pore density of the resiliently deformable region is substantially uniform in an undeformed state.

15. (canceled)

16. (canceled)

17. The roller according to claim 1, wherein the interior roller body comprises a roller support shaft surrounded by the resiliently deformable region.

18. (canceled)

19. (canceled)

20. A vacuum cleaner head comprising a roller, the roller comprising: an interior roller body which comprises a resiliently deformable region; and an exterior abrasion-resistant skin which surrounds the interior roller body, wherein the exterior abrasion-resistant skin is formed from a non-porous material and exhibits an abrasion loss, during abrasion resistance testing according to DIN 53516, of no greater than 150 mm.sup.3.

21. (canceled)

22. (canceled)

23. A method of manufacturing a roller for a vacuum cleaner, the method comprising: forming an interior roller body having a resiliently deformable region; and forming an exterior abrasion-resistant skin which surrounds the interior roller body, wherein the exterior abrasion-resistant skin is formed from a non-porous material and exhibits an abrasion loss, during abrasion resistance testing according to DIN 53516, of no greater than 150 mm.sup.3.

24. (canceled)

25. The method according to claim 23 comprising forming the interior roller body within a preformed sheath, the preformed sheath corresponding to the exterior abrasion-resistant skin.

26. The method according to claim 23 comprising forming the interior roller body and subsequently forming the exterior abrasion-resistant skin around the interior roller body.

27. The method according to claim 26 comprising inserting the interior roller body into a preformed sheath, the preformed sheath corresponding to the exterior abrasion-resistant skin.

28. The method according to claim 23 comprising adhering a preformed sheath to the interior roller body, the preformed sheath corresponding to the exterior abrasion-resistant skin.

29. The roller according to claim 1, wherein the exterior abrasion-resistant skin and the interior roller body are held in contact by an interference fit between the exterior abrasion-resistant skin and the interior roller body.

Description

FIGURES

[0069] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0070] FIG. 1 shows a vacuum cleaner with a cleaner head;

[0071] FIG. 2 shows a front view of the cleaner head of FIG. 1;

[0072] FIG. 3 shows a cross-section of the cleaner head of FIG. 2;

[0073] FIG. 4 shows a cross-section of a roller of the cleaner head of FIGS. 1, 2 and 3; and

[0074] FIG. 5 illustrates schematically a method of manufacturing a roller for a vacuum cleaner head.

DETAILED DESCRIPTION

[0075] FIG. 1 shows a vacuum cleaner 1 comprising a cleaner head 10, a separation system 2, a suction source 3 and duct 7 which connects to the cleaner head 10. The separation system 2 and the suction source 3 may be housed within a housing 6. The vacuum cleaner 1 comprises a handle 9 for pushing the cleaner head across a floor surface.

[0076] Duct 7 is fluidly connected to the cleaner head 10 and to the separation system 2. Duct 7 is configured to carry dirt-laden fluid (e.g. air) from the cleaner head 10 to the separation system 2. Duct 7 may be a flexible hose, rigid pipe or any other type of fluid-carrying duct.

[0077] The separation system 2 is configured to separate dirt/dust/debris from the fluid received via duct 7. The separation system 2 can be of any kind, such as a filter bag, a cyclonic separation system (with one or more cyclonic separation stages), a water filter, an electrostatic filter. The separation system may comprise a porous filter, or may not comprise a porous filter. The suction source 3 may comprise an electrical motor 4 and an impeller 5. The suction source 3 may be located downstream of the separation system 2, or the suction source 3 may be located upstream of the separation system 2. Locating the suction source 3 downstream of the separation system 2 is advantageous, as the suction source operates upon cleaned fluid (air) rather than dirt-laden fluid. The “fluid” that is carried along duct 7 may be air. Alternatively, the fluid may be water, a cleaning fluid, or some other fluid.

[0078] FIG. 2 shows the cleaner head 10 with duct 7. Although the duct shown is central it could be offset or positioned anywhere along the width of the cleaner head 10.

[0079] FIG. 3 shows a cross-section A-A through the cleaner head of FIG. 2. The cleaner head 10 comprises a housing 11. The housing 11 has a lower face 12. This is often called a sole plate. The lower face is the part of the cleaner head 10 which faces a floor surface. The lower face 12 comprises a frame of the housing 11 with apertures defined in it to allow air flow to/from the floor surface, and to allow components such as the roller 40 and an agitator 60 to make contact with the floor surface. The agitator in this embodiment is constructed of radially protruding stiff nylon bristles 63 which are designed to impart a parting force to the carpet pile. However, in other embodiments the agitator may take a different design or even be absent. The lower face 12 is configured to move across a surface to be cleaned. The housing may comprise one or more wheels 16, rollers or other features to assist movement of the cleaner head 10 across a floor surface.

[0080] The cleaner head 10 comprises a suction inlet 20 defined in the lower face (sole plate) 12 of the housing. There is a suction passageway 20A through the housing 11. The suction passageway 20A is in fluid communication with the suction inlet 20 and with the duct 7. The cleaner head 10 comprises the roller 40 located at a front of the housing 11. The roller 40 is configured for rotation about a rotational axis 41. For example, the roller 40 may be supported by the housing 12 at each end. The rotational axis 41 is parallel to the lower face 12 of the cleaner head. The housing 11 at least partially surrounds the roller 40. In this example, the housing 11 surrounds an upper portion of the roller 40, above the rotational axis 41. A lower portion of the roller 40 is configured to make contact with the surface to be cleaned. The front of the roller 40 is exposed, allowing the roller 40 to serve as a bumper when the cleaner head 10 pushes against an upright object, such as a skirting board or furniture.

[0081] FIG. 3 shows the cleaner head comprising an agitator, such as a beater bar (brush bar) 60. A drive, such as an electric motor, is provided to drive the agitator 60. The agitator 60 may rotate at speeds of up to 20000 RPM for effective agitation of carpets and rugs. The drive for the agitator 60 may be turned on and off, such as by a switch on the vacuum cleaner. For example, a user may choose to switch the agitator off when cleaning hard floors, where there is not a need to “beat” the carpet. A single drive may be provided for both the agitator 60 and the rotatable element 40, with transmission to distribute motor power to the agitator 60 and the roller 40. The roller is preferably rotated at speeds in the range of 30-500 RPM for example but could equally operate in the range of 500-2000 RPM.

[0082] The structure of the roller 40 is shown in more detail in FIG. 4. The roller 40 includes an interior roller body, including a region of resiliently deformable (e.g. compressible) material 42 and a roller shaft 44, and an exterior abrasion-resistant skin 43.

[0083] The resiliently deformable (e.g. compressible) material of the interior roller body 42 may be a foam, such as an open-cell foam (for example, having a porosity of between about 30 and 100 ppi) or a closed-cell foam (for example, a flexible polyurethane foam or a latex foam), or any other suitable deformable (e.g. compressible) material such as an elastomeric material (e.g. a soft rubber) or a viscoelastic material (e.g. a viscoelastic gel).

[0084] Accordingly, the region of resiliently deformable (e.g. compressible) material 42 may be porous or non-porous, dependent on the material selected. In any case, the region of resiliently deformable (e.g. compressible) material is typically soft. An example of a suitable resiliently deformable (e.g. compressible) material has a Shore A hardness from about 8 to about 15 and a tear resistance of the order of 1 kN/m.

[0085] The exterior abrasion-resistant skin 43 may be formed of any suitable abrasion-resistant material, such as an abrasion-resistant polymer (such as polyether-based thermoplastic polyurethane, polyvinyl chloride or rubber) or an abrasion-resistant fabric (such as a nylon- or aramid-based fabric). The exterior abrasion-resistant skin 43 is typically non-porous. An example of a suitable abrasion-resistant material has a Shore A hardness from about 80 to about 90, a tensile strength of about 50 MPa, a tear resistance greater than about 60 kN/m and an abrasion loss (during abrasion resistance testing according to DIN 53516) less than about 70 mm.sup.3, and preferably less than about 30 mm.sup.3. The exterior abrasion-resistant skin is between about 100 μm and 1000 μm (e.g. between about 200 μm and 300 μm) thick.

[0086] In use, the roller 40 functions as a rotatable sealing element, i.e. the rotatable sealing element 40 can form a seal, or a partial seal, between the cleaner head 10 and a surface to be cleaned. The seal or partial seal is formed by pressing the abrasion-resistant exterior skin 43 of the roller against the surface to be cleaned. The use of a non-porous material to form the exterior skin 43 results in an improved seal and enables use of porous materials, if desired, in manufacturing the resiliently deformable (e.g. compressible) region 42 without loss of suction. In turn, the resiliently deformable (e.g. compressible) material 42 enables the roller 40 to deform (e.g. compress) when rolling over debris to accommodate the debris and then to return to its initial shape after the debris has been removed, such that the exterior abrasion-resistant skin 43 can be maintained in sealing contact with the surface to be cleaned as the roller 40 rolls over the debris. Maintenance of a seal or partial seal limits air being drawn into the vacuum cleaner from the front of the head and encourage air to be drawn from underneath the head. The roller 40 can therefore allow debris to enter the cleaner head 10, rather than pushing the debris in front of the cleaner head, while also maintaining the seal.

[0087] The inventors have found that the particular two-part structure of the roller 40, which includes the abrasion-resistant exterior skin 43 surrounding an interior roller body comprising the resiliently deformable (e.g. compressible) region 42, is particularly advantageous in comparison to a roller having a unitary structure (i.e. having an interior body and exterior surface made of the same material with the same or similar microstructure). In particular, the two-part structure enables the deformability (e.g. compressibility) of the resiliently deformable (e.g. compressible) region and the abrasion-resistance and sealing properties of the exterior skin to be independently optimised. In contrast, a unitary structure made of sufficiently deformable material is typically found to have poor abrasion resistance, while a unitary structure made of abrasion-resistant material is typically found to be excessively hard or heavy such that deformation of the roller when rolling over debris is not possible (leading either to crushing the debris or to loss of the seal between the roller and the surface). The benefits of the two-part structure are more pronounced when there is a distinct interface (i.e. where there is a discontinuous change in composition and/or microstructure) between the resiliently deformable (e.g. compressible) region and the abrasion-resistant skin.

[0088] FIG. 5 illustrates an example method for manufacturing a roller 205 of the same type as roller 40. In step 100, polyether-based thermoplastic polyurethane is extruded to form a cylindrical sheath or sleeve 200 having a thickness, t, of about 100 μm to about 1000 μm (e.g. about 200 μm to 300 μm), a length, L.sub.1, of about 260 mm and a diameter, D, of about 45 mm. The sheath may have a matt or textured surface finish.

[0089] In step 101, the sheath 200 is inserted into a cylindrical mould 201. A roller shaft 203 is inserted into, and aligned with a longitudinal axis of, the sheath 200 within the mould 201. Circular mould end stops 202A and 202B are used to hold the sheath flush against the internal walls of the mould 201. A flexible polyurethane foam 204 is injected into the sheath 200 through pouring hole 202C in end stop 202B, the foam filling the space bounded by the sheath 200, the end stops 202A and 202B, and the roller shaft 203.

[0090] Once filled, the pouring hole 202C is closed by cap 202D. The foam 204 is allowed to cure within the sheath 200 until solid. Vent holes (not shown) in the mould 201 accommodate expansion of the foam.

[0091] In step 102, once the foam 204 has set, the sheath 200 is removed from the mould 201 and the end stops 202A and 202B are removed from within the sheath.

[0092] In step 103, the ends of the sheath 200 are trimmed to achieve a roller 205 having a final roller length, L.sub.2, of about 240 mm. The foam 204 corresponds to the resiliently deformable (e.g. compressible) region of the roller, while the sheath 200 corresponds to the exterior abrasion-resistant skin.

[0093] It will be appreciated that the materials used to manufacture the resiliently deformable (e.g. compressible) region and the exterior abrasion-resistant skin can be varied, as discussed hereinabove, in order to target particular mechanical properties. The cross-sectional shape of the roller may also be varied. The skilled person will also appreciate that a number of a different methods may be used to manufacture to manufacture the roller. For example, in an alternative method of manufacture, the interior body of the roller is formed separately within a mould and the exterior skin is applied to the interior body once formed. For example, a foam could be cured in a mould around a roller shaft to form the interior body, and then a sheet of abrasion resistant material could be adhered to the exterior of the interior body to form the exterior skin. Alternatively, the interior body could be coated in material (for example, by painting, dip-coating or spray-coating) to form the exterior skin.

[0094] It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.