WO1992000693A1

WO1992000693A1 - A bed spring unit

Info

Publication number: WO1992000693A1
Application number: PCT/GB1991/001076
Authority: WO
Inventors: George Watson
Original assignee: Silentnight Holdings Plc
Priority date: 1990-07-11
Filing date: 1991-07-03
Publication date: 1992-01-23
Also published as: GB9015282D0; AU8187791A

Abstract

A spring unit has longitudinally extending rows (9) each made from a continuous length of wire formed into a plurality of adjacent coils. The spring rows (9) are identical save at the longitudinal edges of the spring unit where the respective rows (9a) are made of increased firmness in order to prevent roll-off of the user. In a double spring unit one or more central rows may likewise be made of increased firmness in order to prevent roll-together of the two users.

Description

A BED SPRING UNIT

This invention relates to a spring unit for a bed, for example a sprung base for a divan bed, or a mattress.

It is well known to make such spring units from discrete coil springs held in stable relationship by means of helical connectors. More recently it has been proposed to produce a row of coils from a single length of wire, multiple rows of coils being interconnected by helical connectors extending lengthwise of the rows or transversely of the rows. The rows of coils may extend transversely of the spring unit but it is also known for the rows to extend longitudinally, i.e. from head to foot end of the spring unit. For example European Patent Application No. 0082259A1 shows continuous spring rows extending longitudinally of the spring unit with the coils more densely packed in the centre of the rows to increase the firmness of the spring unit in this region. In UK Patent No. 2198938B a similar spring unit with parallel rows of continuous springs arranged lengthwise of the unit is longitudinally divided into two distinct areas with different load deflection properties to suit the different weights and/or hardness requirements of a pair of users of the double bed spring unit.

It is an object of the present invention to provide an improved spring unit capable of enhancing the comfort of the user or users.

According to the present invention there is provided a spring unit comprising a plurality of longitudinally extending rows each made from a continuous length of wire formed into spaced coils, one or more rows of springs at each longitudinal edge of the unit being made of increased firmness so as to increase the firmness of the spring unit at said edges and inhibit a user from rolling off the unit over said edges.

The invention will now be further described by way of example only with reference to the accompanying drawings, in which :-

Fig. 1 is a diagrammatic plan view of one embodiment of spring unit in accordance with the invention;

Fig. 2 is a side view of one row of springs of Fig. 1;

Fig. 3 is a perspective view of part of the spring unit of Fig. l; Fig. 4 is a diagrammatic plan view of another embodiment of spring unit in accordance with the invention, and

Figs. 5 and 6 are diagrammatic plan views of spring units illustrating the invention.

The first embodiment of spring unit illustrated in Figs. 1 to 3 is of the kind described in the cited European Patent Application in which equally spaced parallel rows 1 extend longitudinally and are interconnected by lengthwise helical connectors 2. As best seen in Fig. 2, a continuous spring row 1 comprises pairs of coil springs 3, 4 with upwardly convergent axis. The springs of each pair 3, 4 are interconnected by their upper ends at 5 and the adjacent pairs are interconnected by their lower ends at 6.

Fig. 4 shows a spring unit of the kind described in the cited UK Patent Application. Lengthwise rows 7 of continuous spring units are interconnected by transverse helicals 8 within a rectangular frame 9.

As so far described the spring units of Figs. 1 to 3 and Fig. 4 are well known for example from the cited patent specifications. Hitherto, however, the spring rows have been of identical construction throughout all or a substantial part of the spring unit. By contrast, in the spring unit of the invention a row of springs at each longitudinal edge of the unit is made of increased firmness. Fig. 5 shows a spring unit for a divan base or mattress of a single bed with continuous spring rows 9 extending longitudinally in equally spaced parallel relationship. The spring unit may be of the kind illustrated in Figs. 1 to 3 or Fig. 4. The outermost row 9a at each longitudinal edge of the spring unit is of increased firmness in order to inhibit roll-off of the user. The increased firmness is achieved by increasing the gauge of the wire thereby increasing the resistance to compression of the constituent springs. Alternatively, some other change producing the same result may be effected, e.g. the diameter of the spring coils may be changed. In the case of a double bed spring unit as illustrated in Fig. 6 a central row 9b may be made of increased firmness as well as the edge rows 9a. This inhibits rolling together of the users of the spring unit. In a large spring unit additional edge or central rows may be made of increased firmness in order to improve the efficacy of the roll prevention features. The remaining spring rows 9 are preferably of uniform firmness but in a modification these rows are made with different load deflection properties in two distinct areas of the spring unit. It is also possible to provide transverse zones of different firmness as is well known for adapting the spring unit to the different loadings of different parts of the human body. For example, a transverse central section of the spring unit may be of greater firmness than adjacent head and foot sections of the unit. This can be achieved by varying the spacing of the coil springs in the individual rows so that the firmness of the spring unit is increased in the areas in which the spring density is higher and reduced in the areas in which it is lower.

Claims

1. A spring unit comprising a plurality of longitudinally extending rows each made from a continuous length of wire formed into spaced coils, one or more rows of springs at each longitudinal edge of the unit being made of increased firmness so as to increase the firmness of the spring unit at said edges and inhibit a user from rolling off the unit over said edges.

2. A spring unit as claimed in claim 1, wherein one or more rows in the centre of the spring unit are of increased firmness so as to inhibit two users from rolling together.

3. A spring unit as claimed in claim 1 or 2, wherein the increased firmness is achieved by making the respective row of heavier gauge wire.

4. A spring unit as claimed in any one of the preceding claims, wherein transverse zones are made of different degrees of firmness.