GB2205740A

GB2205740A - Cushion, mattress or like support

Info

Publication number: GB2205740A
Application number: GB08814144A
Authority: GB
Inventors: Dr Edward M Danczak; Barry Teasdale; Steven Teasdale
Original assignee: MENTOR MEDICAL DEVELOPMENTS
Current assignee: MENTOR MEDICAL DEVELOPMENTS
Priority date: 1987-06-15
Filing date: 1988-06-15
Publication date: 1988-12-21
Also published as: GB8814144D0; GB8713953D0

Abstract

A cushion, mattress or like support has at least one flexible bag (20) located inside an aperture (11) of a member (10). Underneath the member (10) is a layer (12) secured to member (10). On top of the member (10) and bags (20) is a high resilience polyurethane foam member (1) having orthogonally cut grooves on an upper surface thereof (2,3), the grooves providing increased comfort. The bags (20) are filled with fluid and so as to reduce the weight of the bags particles are dispersed into the fluid which have a size and volume such that the comfort of the bag is not affected by said particles. The particles may be, for example, polystyrene beads occupying 20% to 50% by volume of each bag. <IMAGE>

Description

CUSHION, MATTRESS OR LIKE SUPPORT This invention relates to a cushion, mattress or like support and particularly to a liquid filled support.

There is disclosed in US-A-4,189,798 a foam mattress having a torso floatation support comprising a middle foam member having a rectangular aperture therein, a bottom member of plastics or foam material, a flexible inelastic liquid container disposed in the aperture and a top foam member. The mattress of the U.S.A. Patent provides the liquid container in only a portion of the middle foam member so that weight of the overall mattress is reduced since it is a problem of so called "water-beds" that the mass of water is extremely heavy.

The present invention seeks to provide a cushion, matress or like support in which the weight of the fluid provided therein is reduced.

According to this invention there is provided a cushion, mattress or like support including at least one flexible bag containing fluid in which is dispersed particles that are impervious to said fluid, the size and volume of said particles being such that the comfort of said bag is not affected thereby.

Preferably there is provided a support member having an aperture therein, and said at least one flexible bag is located in said aperture.

Advantageously the volume of said particles to fluid is in the range 20% to 50% and preferably in the range 25% to 40%. In a currently preferred embodiment the volume of said particles to fluid is 30%.

Conveniently the particles are formed of a polymer or co-pDlymjer of styrene or substituted styrene and preferably of polystyrene beads.

Advantageously the beads are generally spherical and have an approximate diameter of 3mn.

Preferably the fluid is a water-based gel comprising water and a quantity of filler provided to reduce wave action. In a preferred embodiment the filler is a methyl cellulose powder.

Advantageously the at least one bag is formed from substantially inelastic polyvinylchloride (PVC) and a valve connection is connected thereto for inserting said water and filler. Preferably two bags are provided so that the weight of each bag is reduced.

In a preferred embodiment the aperture is located where a user's torso would normally be positioned in use.

Advantageously the support member is resilient and preferably formed of a polyurethane foam.

Preferably another resilient member is located over said support member and said another resilient member has a hardness which is less than that of said support member.

Advantageously the upper surface of said another resilient member is provided with two crossing sets of grooves for reducing spread of said another resilient member when weight is applied thereto.

Advantageously a removable cover is provided to envelop the combination of said support member, at least one flexible bag and another member. Conveniently the combination is rectangular in shape and said cover has a zip fastener positioned around at least three sides thereof.

Advantageously the cover is coated with flame resistant material.

The invention will now-be described by way of example with reference to the accomPanying drawings in which: Figure 1 shows an exploded perspective view of a mattress in accordance with this invention, and Figure 2 shows a perspective view of the assembled mattress.

The mattress shown in Figure 1 has a top high resilience polyurethane foam member 1 made from 35kg/m3 density and 80-110 Newtons hardness in accordance with British Standard 4443 Part 2 and British Standard 3667 Parts 1 and 2. The member 1 is rectangular and in the top surface of the member there is provided a first set of longitudinal grooves 2 and a second set of transverse grooves 3, the grooves crossing one another at substantially 900 and commencing approximately 10cm from each outer edge of the member 1. The depth of the grooves 2 and 3 is approximately 2.5cm and each set of grooves is such that the pitch of the grooves progressively decreases toward the centre of the member 1 from 7.6cm to 2.5cm.

Positioned to be beneath the member 1 is a support member 10 formed of high resilience polyurethane foam having a density of 26kg/m3 and a hardness of 120-140 Newtons - in accordance with the same British Standard given above for the member 1. An aperture 11 extending completely through the member 10 is formed in the member 10 at a location where a person lying on the mattress would normally position their torso.

Completely covering the underside of the member 10 is a layer 12 of material known under the Trade Mark HYPOLON which is ar ethylene containing sulphur and chlorine having flame retardent properties. The layer 12 of HYPOLON is secured with adhesive and additionallly stabilises the foam member 10 to prevent the member 10 from distorting and thus preventing a fluid containing bag or bags 20 to be described hereinafter from migrating under the member 10. Alternatively a high density foam layer may be used for layer 12.

Located in the aperture 11 are a pair of fluid filled bags 20 made from polyvinyl chloride sheeting (PVC) so that the bags are flexible and substantially inelastic. The bags are secured together with press studs so as to allow easy movement of the bags when they are filled with fluid but which will prevent movement of the bags in other than as a single unit.

The PVC sheeting of which the bags are made is conveniently 0.4mm thick and the sheeting forming the bags is welded by high frequency welding in an offset jaw to prevent loss of material through a process known as "spew". A capped non return valve (not shown) is fitted to each bag to permit filling and emptying of each bag.

Located in each bag is water and 20% to 50%, preferably 30% by volume of the finished bag is filled with polystyrene beads, which are approximately spherical and 3mm in diameter, each bead having a density of 7-8kg/m3. The purpose of the polystyrene beads is to reduce weight and the introduction of polystyrene beads into the bags also has the beneficial aspect of providing some heat insulation.

So as to make the water thicker to reduce wave action and to also provide a small amount of resilience to the water there is added 283gm of methyl cellulose powder filler known under the Trade Mark AVICEL RC 591F.

An anti-microbial preventative made by Bayer and known under the Trade Mark ON-XTRA is added to the previously formed gel mixture which is then agitated until the polystyrene beads, filler and anti-microbial are thoroughly dispersed. A dye manufactured by Bayer under reference number 957/4/082287/03 Blue may be optionally added so that any leak in the bag may be detected. All air is evacuated from the bag and the valve is closed. The assembled parts of Figure 1 are located inside a cover 30 formed from 579 nylon seave proofed with a 113g/m2 coating of flame retardent material HYPOLON. A zip 31 is provided around three sides of the cover 30.

The mattress shown in Figures 1 and 2 is assembled as follows:- 1. The cover 30 is laid open upon a bed upon which the mattress is to be located.

2. The support member 2 in combination with layer 12 is placed on top of the cover.

3. The filled gel bags 20 are placed within the aperture 11 and the studs joining the two bags are snapped together.

4. The top member 1 is laid on to the support member 10 with the sets of grooves 2, 3 uppermost.

5. The top part of the cover is brought over the mattress and the cover is closed by zip fastener 31.

By way of illustration the mattress having the following dimensions has been constructed.

Member 1 - size 190cm x 91cm x 5cm Member 10 - size 190cm x 91cm x 10cm Aperture - 102cm x 61cm positioned 33cm from head end and transversely centrally within member 10 Gel bag 20 - each have size 51cm x 61cm which when filled have an approximate depth of 7.5cm to 10cm.

It will be appreciated that two bags 20 have been described but in dependence upon individual requirements more bags may be used or, provided a single bag can be lifted, then a single bag may be used having similar dimensions to the overall size of the two bags combined, namely 102cm x 61cm.

It will thus be seen that by inserting material into the bags 20 which is lighter and impervious to the liquid so the weight of the mattress is reduced without affecting comfort of a user.

Although the invention has been described in relation to a mattress having a foam member 10 with an aperture 11 therein, the scope of the invention is not intended to be so limited since it will be appreciated a. bag filled with fluid and particles may be used on its own.

Claims

CLAIM:

1. A cushion, mattress or like support including at least one flexible bag containing fluid in which is dispersed particles that are impervious to said fluid, the size and volume of said particles being such that the comfort of said bag is not affected thereby.

2. A cushion, mattress or like support as claimed in claim 1, wherein there is provided a support member having an aperture therein, and said at least one flexible bag is located in said aperture.

3. A cushion, mattress or like support as claimed in claim 1 or 2, wherein the volume of said particles to fluid is in the range 20% to 50%.

4. A cushion, mattress or like support as claimed in claim 3, wherein the volume of said particles to fluid is in the range 25% to 40%.

5. A cushion, mattress or like support as claimed in claim 3 or 4, wherein the volume of said particles to fluid is 30%.

6. A cushion, mattress or like support as claimed in any preceding claim, wherein the particles are formed of a polymer or co-polymer of styrene or substituted styrene.

7. A cushion, mattress or like support as claimed in claim 6, wherein the particles are formed of polystyrene beads.

8. A cushion, mattress or like support as claimed in claim 7, wherein the beads are generally spherical and have an approximate diameter of 3mm.

9. A cushion, mattress or like support as claimed in any preceding claim, wherein the fluid is a water-based gel comprising water and aquantity of filler provided to reduce wave action.

10. A cushion, mattress or like support as claimed in claim 9, wherein the filler is a methyl cellulose powder.

11. A cushion, mattress or like support as claimed in claim 9 or 10, wherein the at least one bag is formed from substantiallyinelastic polyvinylchloride (PVC) and a valve connection is connected thereto for inserting said water and filler.

12. A cushion, mattress or like support as claimed in claim 11, wherein two bags are provided so that the weight of each bag is reduced.

13. A cushion, mattress or like support as claimed in claim 2, wherein the aperture is located where a user's torso would normally be positioned in use.

14. A cushion, mattress or like support as claimed in claim 2, wherein the support member is resilient.

15. A cushion, mattress or like support as claimed in claim 13, wherein the support member is formed of a polyurethane foam.

16. A cushion, mattress or like support as claimed in claim 14 or 15, wherein another resilient member is located over said support member and said another resilient member has a hardness which is less than that of said support member.

17. A cushion, mattress or like support as claimed in claim 16, wherein the upper surface of said another resilient member is provided with two crossing sets of grooves for reducing spread of said another resilient member when weight is applied thereto.

18. A cushion, mattress or like support as claimed in claim 16 or 17, wherein a removable cover is provided to envelop thecombi nat ion of said support member, at least one flexible bag and another member.

19. A cushion, mattress or like support as claimed in claim 18, wherein the canbination is rectangular in shape and said cover has a zip fastener positioned around at least three sides thereof.

20. A cushion, mattress or like support as claimed in claim 19, wherein the cover is coated with flame resistant material.

21. A cushion, mattress or like support substantially as herein described with reference to and as shown in the accompanying drawings.