ZA200504448B - Mattress inner spring assembly - Google Patents

Description

N 1.

BACKGROUND TO THE INVENTION

THIS invention relates to a mattress inner spring assembly.

Persons often sit on the edge of a bed, for example to put on shoes. In the case of a sprung mattress having an inner spring assembly or foundation, the applied weight compresses the springs locally in the edge region of the mattress. As the applied weight is concentrated on only a few edge springs, these springs are prone to collapse, and the edge of the mattress is prone to sagging, with passage of time.

Mattress manufacturers have produced mattresses taking this into account.

For instance a sprung mattress may include fabric panels along its sides which are fastened to the inner spring assembly and which have panels of reconstituted foam glued to them to provide extra resistance to edge deformation of the mattress under locally applied loading. However a problem with this solution is that the foam panels themselves often lose resilience or the glue with which they are fastened to the fabric panels loses adhesion with the result that the foam panels may bulge outwardly in an unsightly manner and lose effectiveness.

It has also been proposed in the present applicant's South African patent application 2004/2454 to provide extra edge resistance using resilient bolsters which are wound sinuously between the springs in the edge regions of the mattress. The installation of the sinuously wound bolster(s) is however a time-consuming process.

tele “ \ 2- : . - o

SUMMARY OF THE INVENTION

According to the invention there is provided a rectangular mattress inner spring assembly having four sides and comprising spring coils arranged in mutually orthogonal rows and, near at least one side of the assembly, a resilient bolster extending in a generally straight line between adjacent rows of springs. Typically the bolster extends in a generally straight line between a row of springs which is closest to the side of the assembly and the row of springs which is next closest to the side of the assembly.

The resilient bolster may be wound at least partially around a comer spring at an end of a row and, in the preferred arrangement, the bolster extends between adjacent rows of springs near all four sides of the assembly, and is wound about comer springs at all four comers of the assembly, thereby to bolster all four sides of the assembly.

The bolster may be provided by a single length of resilient material or by a plurality of lengths of resilient material arranged end to end.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Figure 1 shows a plan view of a mattress inner spring assembly according to this invention;

Figure 2 shows a cross-section at the line 2-2 in Figure 1; and

Figure 3 shows a cross-section at the line 3-3 in Figure 1.

N 3

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

The mattress inner spring assembly 10 seen in Figure 1 is rectangular in shape and includes an array of coil springs 12, in this case so-called

Bonnell springs, arranged in mutually orthogonal rows 14 and 16. Springs in adjacent rows 14 are connected to one another in conventional manner by means of spiral wires 18. The assembly is bounded by upper and lower boundary wires 20 and 22 to which springs in rows 16.1, 16.n and 14.1, ) 14.n are connected by means of upper and lower spiral wires 23, 24.

As thus far described, the inner spring assembly is conventional. What is not conventional about the illustrated assembly 10 is the inclusion of a resilient bolster 26. The bolster 26 in this embodiment is extruded in polyethylene, but in other embodiments could be made of any suitable one of a range of existing, resilient materials such as polyurethane foam.

From its one end 26.1, the bolster 26 extends in a straight line between the springs in rows 14.1 and 14.2, is wound about a comer spring 12.1, extends in a straight line between the springs in rows 16.1 and 16.2, is wound about a comer spring 12.2, extends in a straight line between the springs in rows 14.n-1 and 14.n, is wound about a comer spring 12.3, extends in a straight line between the springs in rows 16.n-1 and 16.n, is wound about a comer spring 12.4, and finally extends in a straight line again between the springs in the rows 14.1 and 14.2 to terminate at its other end 26.2 adjacent the first end 26.1. Thus it will be seen that the single bolster 26 extends about the full periphery of the inner spring assembly 10. Along each side of the assembly, the bolster extends in a straight line between the springs in the first and second rows closest to the edge.

The bolster 26 accordingly provides additional resilient support along all four sides of the inner spring assembly 10 and accordingly along all four sides of the eventual mattress which is formed by enveloping the assembly in a quilted and padded or other cover (not shown).

N 4.

It is also recognised that a spring mattress can have a tendency to sag in a middie region corresponding to the position of the waist of a person lying on the mattress. This is because the greatest load can usually be expected to be present in this region. To address this potential problem, the inner spring assembly 10 illustrated in the drawings also includes further bolsters 28 extending transversely across the width of the assembly between the springs in relevant rows 14.

In the illustrated embodiment, a single length of resilient material is used to form the bolster 26, but it will be understood that in other embodiments, a corresponding bolster can be formed by a number of individual lengths of resilient material arranged end to end with one another.

An advantage of the edge bolster arrangement described above compared to that described in applicant's patent application ZA 2004/2454 is the fact that the bolster can be installed relatively quickly and easily. This is because it is laid out in straight lines between adjacent rows of springs over much of its length. Another advantage is the fact that the largely straight configuration of the bolster, as opposed to the sinuous configuration proposed in ZA2004/2454, reduces the overall length, and accordingly cost, of the bolster.

Claims (9)

” : Z § . oo Co ~ CLAIMS

1. A rectangular mattress inner spring assembly having four sides and comprising spring coils arranged in mutually orthogonal rows and, near at least one side of the assembly, a resilient bolster extending in a generally straight line between adjacent rows of springs.

2. An assembly according to claim 2 wherein the bolster extends in a generally straight line between a row of springs which is closest to the side of the assembly and the row of springs which is next closest to the side of the assembly.

3. An assembly according to claim 1 or claim 2 wherein the resilient bolster is wound at least partially around a corner spring at an end of a row.

4. An assembly according to any one of the preceding claims wherein the bolster extends between adjacent rows of springs near all four sides of the assembly and is wound about corner springs at all four comers of the assembly, thereby to bolster all four sides of the assembly.

5. An assembly according to claim 4 wherein the bolster is provided by a single length of resilient material.

sf Tne

6. An assembly according to claim 4 wherein the bolster is provided by a plurality of lengths of resilient material amanged end to end.

7. An assembly according to claim 5 or claim 6 wherein the, or each, length of resilient material is a length of extruded polyethylene or polyurethane foam.

8. An assembly according to any one of the preceding claims and including further bolsters extending transversely across the assembly between adjacent rows of springs in a middle region of the assembly.

9. A mattress inner spring assembly substantially as herein described with reference to the accompanying drawings. DATED THIS 31ST DAY OF MAY 2005 POOR & FISHER APPLICANTS PATENT ATTORNEYS