GB2269989A - Mattress and seating system - Google Patents

Abstract

A mattress uses a spring assembly and foam construction in which a foam surround layer has grooves 50, 51, 52 cut in a first surface thereof in order to facilitate the folding of the said foam surround layer around the spring assembly. The mattress is designed to be of light weight construction with particular applications in the recreational vehicle field. The mattress includes a spring assembly 12 including a plurality of coiled springs 14, the spring assembly defining a volume having upper and lower outer surfaces each bounded by a peripheral edge, the peripheral edges separated by side surfaces; and the foam surround layer having the first surface adjacent to at least some of the upper, lower and side surfaces of the said spring assembly and each of the grooves 50, 51, 52 being coincident with a portion of said peripheral edges of said spring assembly. <IMAGE>

Description

MATTRESS AND SEATING SYSTEM The present invention relates to mattresses and seating systems, with particular applicability to the light-weight requirements of such systems in caravans, mobile homes, recreational vehicles, portable buildings and the like. It will, however, be apparent that the present invention need not be limited to these applications, and may be suitable for general use as a seating and/or bedding system. Throughout the present specification, the term mattress will be used to include seating cushions or squabs.

In recreational vehicles, it is a common requirement to provide convertible bedding and seating arrangements, and typically the resilient support of such systems is provided by means of foam squabs which can confer advantages in respect of their light weight over known spring and padding mattress systems, and the manner in which they may easily be cut to form shaped supports to suit a particular cushion, mattress and seat arrangement.

There are a number of known problems with such systems. Firstly, it is commonly recognised that light weight foam seating and mattress systems do not offer the same type of support to a user of the mattress that can be expected of conventional sprung mattresses such as commonly found in domestic bedding systems. Thus, in order to achieve the light weight advantages of foam, some compromises must be made. Secondly, a known problem of foam mattresses is that of inadequate ventilation in order to dissipate moisture which naturally is absorbed by the foam when in use, for example by a sleeping person. This is particularly relevant in the case of recreational vehicles, where overnight condensation and poor ventilation are likely.Such mattresses are commonly supported on a wooden base which may form part of a binnacle or the like, and is typically predrilled with a number of ventilation holes which are of necessity restricted in size and number in order to maintain the mechanical strength of the base.

A third problem with foam mattress systems is that, although high resilient foam is now commonly used, it is recognized that the long term resilience of the product is not of the same standard as a sprung mattress. A further problem with foam products is that of combustibility. New foam products which have fire resistant or fire retardant properties tend, in general, to be heavier than their nonfire resistant counterparts, further compromising the weight advantages.

It is an object of the present invention to provide a mattress which combines the advantages of a sprung interior mattress with the light weight and shaping advantages of a foam mattress arrangement.

Embodiments of the present invention will now be described in detail and with reference to the accompanying drawings in which: Figure 1 shows in perspective view a cross-section through a mattress according to the present invention; Figure 2 shows in side elevation a cross-sectional view of a foam surround used in order to manufacture the mattress according to figure 1; and Figure 3 shows in side elevation a cross-sectional view of the foam surround of figure 2 formed into its final shape for use in the interior of the mattress of figure 1.

With reference to figure 1, there is shown a mattress 10 incorporating a light weight spring assembly 12 which comprises a plurality of coil springs 14 each of which is coupled to a suitable upper and lower framework 16,18 in a manner well known in the art, such as by helical coils as shown. In order to achieve the objectives of light weight construction, the spring assembly 12 is, in a presently preferred embodiment, substantially constructed of high tensile 12.75 gauge bedding and seating wire of crosssection 2.2 mm. A number of spring assembly designs are readily adaptable or suitable to the present invention which is not limited to the single embodiment shown.

The spring assembly is enveloped in a suitable fabric mechanical protection layer 20 such as coravin or, in a preferred embodiment, with an upper surface of 170g compressed fibre insulator material. This provides protrusion protection against springs causing damage to outer layers of the mattress, and also may provide a better weight distribution of the person seated/lying on the mattress over the adjacent springs. The fabric envelope need not be continuous around the mattress, and may be provided differently in respect of the upper, lower and side surfaces of the mattress. The fabric envelope may include fire retardant features, and prevent springs bursting through melting foam in the event of a fire.

A foam spring surround layer 30 is then provided which may be manufactured from 32oz/cu.ft (32kg/m3) combustion modified high resilient (CMHR) foam, or other suitable specification material. The foam layer is preformed and machined according to figure 2 which is described hereinafter. The spring assembly 12 and coravin envelope 20 need not be fixed inside the foam spring surround layer 30, but are effectively held in place by the dimensional constraint of the inner volume formed by the foam layer 30.

Shaping blocks of foam 32 may be affixed to the foam spring surround layer 30 at suitable positions in order to meet the specific requirements of the mattress location.

This provides the advantages relating to provision of shaped seating arrangements often required in recreational vehicles, and may provide a pillow area, cushioned back support, shaped corner section or adjoining surface to a separate mattress/squab arrangement as required.

A cover 40 is then provided to envelop the mattress, which may include inner scrim layer 42, 250z/cu.ft (25kg/m3) CMHR foam layer 44, and upholstery cover layer 46. The scrim layer provides a fabric backing material giving mechanical strength to allow sewing through the foam layer in order to allow the cover 40 to be quilted or buttoned 48, preventing thread pull through the foam layer.

Where weight considerations will allow, it is possible to include further layers of, for example, coir fibre pads, cotton, wool or felt in addition to, or instead of some of the foam layers and/or coravin layer.

With reference to figure 2, the detail of an embodiment of foam spring surround layer 30 is now described. The foam layer 30 is cut from a sheet of suitable thickness CMI{ foam material having width sufficient to surround the spring assembly 12, and length equal to the length of the spring assembly 12. The foam layer 30 is then machined by known methods, such as by use of a CNC foam conversion machine, to form a number of "V" grooves 50,51,52 in a first (inner) surface 60 thereof, which extend along the length of the foam layer.In the embodiment shown, where the finally formed mattress is of square cornered section, the V-grooves are cut with approximately 90 degree inner angle, and to a depth of, for example two-thirds of the thickness of the foam layer 30, sufficient to allow the formation of a right angle bend in the foam layer around the spring assembly 12 without causing undue stress or tearing on the second (outer) surface 61 of the foam layer, and while retaining sufficient foam material for mechanical strength.

In the embodiment shown, therefore, the foam layer 30 is divided by the V-grooves 50,51,52 into four areas 65,66,67,68 which form the first side, upper, second side, and lower portions of the mattress respectively. The foam layer 30 is then placed around the spring assembly with Vgrooves suitably located at the corners of the spring assembly, and mating surfaces 55,56 suitably bonded together using known techniques. Figure 3 shows the assembled entity, with foam layer 30 encasing spring assembly 12.

Any additional surface features required, such as shaping block 32 may be cut individually and bonded to the appropriate portion of the foam layer 30 as shown, using one of a variety of bonding methods well known in the art, such as gluing.

As an alternative to machining the V-grooves and gluing any additional shaping blocks of foam, it is possible to provide the foam layer 30 preformed to the required shape.

Should it be necessary to provide a mattress with nonvertical sides 65,67, this can be readily achieved by use of V-grooves 50,51,52 having appropriately modified internal angles and filler blocks accommodating any angular difference between the foam walls 65 and 67 and the spring assembly 12 sides.

The foam layer side portions 65,67 may also have holes formed therethrough which will provide a greater degree of ventilation of the interior of the mattress, allowing faster egress of moisture.

The ends of the mattress 70 (see figure 1: one end shown only) may be formed in a number of ways. Additional blocks of foam or other fabric may be bonded to the end faces of foam layer 30 using known techniques, thus sealing the spring assembly in at each end of the mattress.

Alternatively, further V-grooves may be formed transversely to v-grooves 50,51,52 at each end of upper portion 66 of foam layer 30, upper portion 66 of foam layer 30 being cut greater in length than side portions 65,67 or lower portion 68 to provide end portions 70.

Claims (7)

1 A mattress including: a spring assembly, a foam suround layer, said foam surround layer being provided with a plurality of grooves to enable the foam surround layer to be at least partially wrapped around the spring assembly.

2 A mattress according to claim 1 wherein: said spring assembly includes a plurality of coiled springs, said spring assembly defining a volume having upper and lower outer surfaces each bounded by a peripheral edge, said peripheral edges separated by side surfaces; and wherein said foam surround layer has a first surface with said plurality of grooves formed therein, said first surface being adjacent at least some of the upper, lower and side surfaces of said spring assembly and each of said grooves being coincident with a portion of said peripheral edges of said spring assembly and facilitating the folding of said foam surround layer around said spring assembly.

3 A mattress according to claim 1 wherein said spring assembly is manufactured from high tensile 12.75 gauge bedding and seating wire.

4 A mattress according to claim 1 further comprising a fabric envelope at least partially surrounding said spring assembly and situated between said spring assembly and said foam surround layer.

5 A mattress according to claim 1 wherein said foam surround portion further includes a shaping block portion to modify the external dimensions of said mattress.

6 A mattress according to claim 1 further comprising a foam and upholstery cover at least partially enclosing said foam surround layer.

7 A method of manufacturing a mattress having a spring assembly which defines a volume having first and second outer surfaces each bounded by a peripheral edge, said peripheral edges separated by side surfaces, said mattress also including a foam surround layer at least partially encasing said spring layer, said method including the following steps: forming a plurality of grooves in a first surface of said foam surround layer; placing said first surface of said foam surround layer in contact with said first surface of said spring assembly such that said grooves coincide with at least a portion of said peripheral edge; folding said foam surround layer at said grooves in order to at least partially encase the spring assembly.