GB2032051A - Spring - Google Patents

Abstract

A wire spring (30) comprising two load-bearing portions (31, 32) linked by a central portion (33). An applied load on the load-bearing portions (31, 32) induces torsion within the central portion (33). Each load-bearing portion may have a rectangular configuration (as illustrated) or may be triangular, circular, or circular-segmental. A plurality of such springs may be attached to a core to form a spring unit or arranged so that the load- bearing portions co-operate to form a "composite" spring which may be used in a cylindrical upholstered article such as a pouffe. <IMAGE>

Description

SPECIFICATION Absorption of movement between two surfaces This invention relates to an improved torsion spring, to a device for the absorption of movement between two mutually parallel surfaces, the device including a plurality of such tqrsion springs, and to an upholstered article including such a device.

Movement between two mutually parallel surfaces can occur in packaging applications and in upholstered articles, especially in seating and bedding components. Hitherto, such movement has been absorbed by means of an assembly of helical springs arranged between the two parallel surfaces. It has been found, however, that helical springs have only a limited amount of displacement available before the spring compacts to a solid "pillar" and that adjacent helical springs have to be attached one to another to prevent movement apart on the application of a load.

We have found that may of the disadvantages associated with helical springs can be avoided by the use of torsion springs formed into an assembly to absorb movement between surfaces.

Thus the present invention provides a torsion spring comprising two load-bearing members linked by a central member, the central member being disposed at an angle of 90 degrees to the direction of an applied load on the said loadbearing members, whereby the application of a load on the load-bearing mebers induces torsion within the said central member.

In a second aspect, the present invention provides a device for absorbing movement between two mutually parallel surfaces, the device comprising a plurality of torsion springs assembled on a core at a predetermined distance one from another, the torsion springs being of the type defined in the immediately-preceding paragraph.

The core may be made of a formable, substantially rigid material, e.g. wire or a plastics material, and may be formed into any desired configuration. In a preferred embodiment of the present invention, the core may be formed into a substantially rectangular or substantially sinous configuration, whereby a resilient device is achieved.

Alternatively, the core may comprise a sheet of a material having sufficient rigidity to support an applied load on the torsion springs (e.g. wood, harboard or a plastics material).

A device according to the second aspect of the present invention may consist of a plurality of torsion springs attached to a wire core, the core then formed intoa substantially sinusoidal configuration and used as a "spring case" for an upholstery or bedding component.

In one preferred embodiment of a torsion spring according to the present invention, one of the load-bearing members may comprise an anchorage member to be secured to a wire core or other substantially rigid layer.

In a second preferred embodiment, it is the central member of the torsion spring which is attached to the core or substantially rigid layer.

The torsion springs may suitably be made of formed metal or moulded or formed plastics material.

The present invention will be illustrated, merely by way of example, in the following description and with reference to the accompanying drawings.

In the drawings: Figure 1 is a perspective view of one form of torsion spring according to the present invention; Figure 2 is a schematic perspective view of an alternative form of torsion spring according to the present invention; Figure 3 is a schematic perspective view of an alternative form of the torsion spring illustrated in Figure 2; Figure 4 is a schematic plan view of a device according to the second aspect of the present invention.

Referring now to Figure 1, a torsion spring 20 comprises two ioad-bearing members 21 and 22 linked by a central member 23. Load-bearing member 22 consists of an anchorage member and is secured (by means not shown) to two parallel core wires VV' and WW'. Application of a load on member 21 induces a torsional force in central member 23. In an alternative embodiment, the spring illustrated in Figure 1 may have its loadbearing member 22 secured to a flat surface.

In Figure 2, a torsion spring 30 comprises loadbearing members 31 and 32 and a central member 33 which is attached (by means not shown) to a core XX'. The torsion spring 40 illustrated in Figure 3 has two load-bearing members 41 and 42 and a central member 43 which is attached to two parallel core wires W' and ZZ'. In each case, application of a load on members 31, 32 or 41, 42 results in a torsional force being induced in members 33 and 43 respectively.

Referring now to Figure 4, a plurality of torsion springs 10 is attached by means of conventional "clench-clips" (not shown) to a core 11. The core comprises a wire and, as illustrated in Figure 4, is bent into a substantially sinuous configuration.

Struts, shown schematically by means of chaindotted lines at 12, 13 and 14, are attached to and between adjacent corners of the core 11 to provide stability for the assembly.

The device illustrated in Figure 4 may be used as a "spring-case" in an upholstery component.

Although the load-bearing members of the springs illustrated herein have been made with substantially rectangular configurations, other configurations such as triangular, circular or circular-segmental can be used. In the lastmentioned instance, a plurality of torsion springs whose load-bearing members have a circularsegmental configuration may be so arranged that the load-bearing members co-operate to form a "composite spring" of substantially circular configuration. Such a "composite spring" may be used as a "spring case" for a cylindrical upholstered article such as a pouffe.

Claims (19)

1. A torsion spring comprising two load-bearing members linked by a central member, the central member being disposed at an angle of 90 degrees to the direction of an applied load on the said load-bearing members, whereby the application of a load on the load-bearing members induces torsion within the said central member.

2. A torsion spring according to Claim 1, in which one of the load-bearing members comprises an anchorage member.

3. A torsion spring according to Claim 1 or 2, which is made of a metal.

4. A torsion spring according to Claim 1 or 2, which is made of a plastics material.

5. A torsion spring according to any one of Claims 1 to 4, in which the load-bearing members are of substantially rectangular configuration.

6. A torsion spring according to any one of Claims 1 to 4, in which the load-bearing members are of substantially circular-segmental configuration.

7. A torsion spring, substantially as hereinbefore described, with reference to and as illustrated in Figures 1, 2 and 3 of the accompanying drawings.

8. A device for absorbing movement between two mutually parallel surfaces, the device comprising a plurality of torsion springs assembled on a core at a predetermined distance one from another, in which each torsion spring is a torsion spring according to any one of Claims 1 to 7.

9. A device according to Claim 8, in which each torsion spring is attached to the core by one of its load-bearing members.

10. A device according to Claim 8, in which each torsion spring is attached to the core by its central member.

1 A device according to Claim 8, 9 or 10, in which the core is made of a formable, substantially rigid material.

12. A device according to Claim 11, in which the core is made of wire.

13. A device according to Claim 1 1, in which the core is made of a plastics material.

14. A device according to Claim 11, 12 or 13, in which the core is of substantially rectangular configuration.

15. A device according to Claim 11, 12 or 13, in which the core is of substantially sinuous configuration.

16. A device according to Claim 8, 9 or 10, in which the core comprises a sheet os substantially rigid material.

1 7. A device according to Claim 16, in which the core is made of wood, hardboard or plastics material.

18. A device for absorbing movement between two mutually parallel surfaces, substantially as hereinbefore described, with reference to and as illustrated in Figure 4 of the accompanying drawings.

19. An article of furniture including a device according to any one of Claims 8 to 18.