GB2520264A

GB2520264A - Seat cushion

Info

Publication number: GB2520264A
Application number: GB1319982.3A
Authority: GB
Inventors: Lars Bruns
Original assignee: AKVA WATERBEDS AS
Current assignee: AKVA WATERBEDS AS
Priority date: 2013-11-13
Filing date: 2013-11-13
Publication date: 2015-05-20
Also published as: GB201319982D0

Abstract

A seat cushion comprising a foam base 4 and a liquid containing element 5 retained in the base 4 wherein the liquid containing element 5 is self contained and spaced from lateral sides of the foam base 4. The foam base 4 may form an aperture 6 for receiving and surrounding the liquid element 5 and the height of the foam may be greater than the liquid element when positioned in the aperture. There may be a pair of liquid elements 5 whose height can be adjusted using inserts 9 and the liquid elements 5 may have two compartments with a passage controlling movement between the compartments. The liquid elements 5 may be filled with foam and an aqueous fluid which is either viscous or a gel and may include a bactericide or algaecide. A cover 3 with a friction enhancing area may be provided and the cushion may be used as part of a wheelchair to help relieve pressure sores.

Description

Seat Cushion

Field of the Invention

The present invention relates to a seat cushion, particularly for physically disabled persons. Such seat cushions are predominantly used in wheelchairs, and some-times in armchairs, for preventing or relieving pressure sores on buttocks and upper thighs.

The invention also concerns a seat and a wheelchair, respectively, comprising such a seat cushion.

Background of the Invention

Seat cushions of the above mentioned kind have been made in many configura- tions. It is common provide seat cushions having a padding with various pressure-relieving means, including foam rubber, and with artificial or natural fleece for insulation. It is also prior art to combine these padding means with fluid means as known from mattresses for patients with decubitus ulcers or from waterbeds. Flu-ids, especially liquids, are efficient in distributing pressures or forces coming from certain points on human bodies over a larger area so that the pressure on the sores or vulnerable points of the person's skin is relieved and distributed to areas of the skin which are less vulnerable.

US 5613256 discloses a wheelchair seat cushion system including a padding com-bining a foam material and liquid-containing elements. The purpose of this system is to reduce the weight of fluid-filled cushions, to make the seat cushion more handy and to avoid a hammock effect that renders the distributing action of the fluid ineffective. This document describes various dispositions of padding including two elongated side cushions that may be positioned relative to a central section, according to need. A liquid compartment is provided as padding in the central section, extending to the rear edge of the central section and of the seat cushion.

The liquid compartment is provided as a generally flat enclosure with weldings or flow controls for slowing liquid flow in the compartment. While adaptable to some degrees, this prior art seat cushion system is rather complicated in design and does not provide the option of adjusting the support height of any liquid com-partment or replacing the compartment.

GB 1032354 discloses a seat squab that may contain a single or a plurality of compartments filled with a liquid or with a fluid-containing material such as latex foam. With a single compartment covering most of its area, the seat squab may be covered at the top and on four lateral sides with padding material. The com- partment or compartments are integrated parts of the seat squab and not ex-changeable.

Us 5839788 discloses a chair with integrated compartments filled with liquid. The compartments are deeply embedded in and evenly distributed across the seat and backrest.

Us 6206474 B1 discloses a car seat having liquid-filled chambers embedded in the upholstery. The chambers are interconnected through passages for liquid ex-change between the chambers.

Object of the Invention An object of the invention is to provide a seat cushion of a more simple design than the prior art, and with a replaceable or adjustable liquid-containing element that may relieve or prevent pressure sores.

A further object of the invention is provide a seat cushion with at least one liquid-containing element and which can be easily be handled and carried as a separate unit.

A further object of the invention is to provide a seat cushion wherein one or more pressure-distributing liquid-containing element can be adjusted in position, espe-cially in height.

Description of the Invention

These and other objects are achieved by a seat cushion as indicated in the intro- duction, including a padding combining a foam material and at least one liquid- containing element, the invention being peculiar in that the liquid-containing ele-ment is a self-contained unit which is spaced apart from lateral sides of the seat padding, and wherein foam material is provided around the liquid-containing ele-ment or elements along lateral sides of the padding.

The self-contained units with liquid can be replaced or adjusted in position, thus providing easy and individual adaptation of the seat cushion to the user's needs.

Liquid-containing elements can be reserved to the area on the seat cushion where they are most in need, namely close to the centre of the seat cushion, where oth-er areas are padded with foam, thus reducing the size of the heavier components of the padding and thereby the overall weight of the seat cushion.

According to a simple embodiment of the invention, the foam material is provided as a continuous foam frame surrounding an aperture for receiving liquid-containing elements. The foam frame may thereby be produced as a single unit in a mould. The aperture is preferably through-going, though an aperture provided as a blind hole in the foam frame is possible within the scope of the invention. The aperture for receiving the liquid-containing elements can be provided with differ-ent geometrical shapes, e.g. rectangular, circular, oval, polygonal or with a shape designed more specifically to the body shape of a user. In its simplest form, the seat cushion according to the invention is composed of one liquid-containing ele-ment provided in the aperture of a foam frame, both held together and enclosed by a flexible cover of fabric or plastic-coated textile.

In one embodiment, the foam frame has a constant height around the central aperture, wherein the liquid-containing element or elements have a height which is less than the height of the foam frame. It is hereby possible to some degree equalise the difference in supporting forces between the foam on the one hand and the liquid-containing element or elements on the other, as the foam will be compressed slightly before the liquid-containing element will come into contact with the user.

It is preferred that the difference in height between foam frame and element is between 10 and 30 mm.

In a further embodiment according to the invention, the seat cushion includes two liquid-containing elements arranged juxtaposed side by side at respective sides of a vertical plane of symmetry of the seat cushion. It is thereby possible to adjust the height of individual elements in case that the user is in need for different sup-port at respective sides of the said vertical plane. The same advantage goes for the situation where different contents with regard to the characteristics or the amount of the liquid in the elements are possible. Also, smaller elements contain-ing less liquid or elements with different height may be advantageous in some cases.

If the seat cushion according to the invention comprises two liquid-containing el-ements, they can be made separately adjustable in height relative to the foam material, the adjustment provided by changing one or more inserts located under the liquid-containing elements for the purpose mentioned above.

In a further embodiment of the seat cushion according to the invention there is provided a liquid-containing element which is divided into two internal compart-ments by a partitioning extending along a vertical plane of symmetry of the seat cushion, wherein a passage is arranged in the partitioning for providing or con- trolling fluid communication between the compartments. An uneven or asymmet-rical position of the user, e.g. caused by disability, can hereby be compensated by this feature as the liquid can flow slowly from one compartment to the other, thus accommodating to the pressure from the user's bottom parts.

It is preferred that each liquid-containing element is filled with aqueous fluid, and another open-cellular foam material is provided in each liquid-containing element for distending the element. The liquid-containing element is thereby in reality filled with a liquid-containing foam, the foam providing some stabilisation to the liquid. Also, the foam provides assistance when filling liquid into the element, as the foam can suck the liquid into the compartment while expanding from a com-pressed state to a fully expanded state.

The aqueous fluid preferably contains a bactericide and/or an algaecide.

In order to impede uncomfortable sloshing in the seat cushion caused by the us-er's movements, the liquid-containing elements may contain a viscous fluid or an aqueous gel. The increased viscosity of e.g. water may be provided by known means.

An advantage of the seat cushion according to the invention is that the liquid- containing element/elements is/are exchangeable. Apart from previously men-tioned benefits this particularly an advantage if a liquid-containing element is leaking and needs to be replaced.

For any practical reasons, the seat cushion according to the invention includes a cover enclosing the padding, the cover provided with a friction-enhancing part at a side facing downwards in the position of use and which is intended for contact with an underlying base. Inadvertent movements of the seat cushion relative to the base, i.e. a wheelchair seat or the seat of a chair, are hereby prevented.

It is noted that by the invention other component parts can be applied in combi-nation with the foam and the liquid-containing element, for example stiffening members etc. Such further components may advantageously be combined in the seat cushion according to the invention, especially if contained within a flexible cover of fabric or plastic-coated textile.

The seat cushion according to the invention is intended as a separate unit for ap- plication on wheelchairs or armchair and provided as an easily carried part. How- ever, the seat cushion according to the invention may also be a part of a wheel-chair or a seat for an otherwise common chair, either forming part of these or provided as a semi-permanent part thereof, e.g. attached by Velcro® bands.

Description of the Drawing

Embodiments of the invention will be described in more detail below with refer-ence to the drawing, in which: Fig. 1 is a cross-sectional view of an embodiment of a seat cushion according to the invention; Fig. 2 shows a sectional view on the line TI-IT on Fig. 1; Fig. 3 shows a plan view of padding in the seat cushion in Fig. 1; Fig. 4 shows a liquid-containing element for use in the seat cushion, as seen from above; Fig. 5 shows a foam insert for use in the liquid-containing element in perspec-tive view.

Detailed Description of Example Embodiments

Figs. 1 and 2 show a transverse and a longitudinal cross-sectional view, respec-tively, of a first embodiment of a seat cushion according to the invention, with a top side 1 and a bottom side 2, as applied in the situation of use. The seat cush-ion is externally enclosed by a cover 3, preferably of a fabric and possibly coated by plastic, where the bottom side of the cover 3a can be adapted with a friction-enhancing material so that the seat cushion will not slide when used e.g. on a wheelchair.

The cover is preferably closed by a not shown zip fastener so that the contents of the seat cushion including padding can easily be substituted or adjusted. Also, the cover may be provided with further means, (not shown) for attaching the seat cushion to the seat of a wheelchair or to a stationary chair.

Inside the cover 3 is located a padding, see al5o the view from above in Fig. 3, comprising a foam frame 4 and one or more liquid-containing elements 5, the shown embodiment having two elements 5. The foam frame 4 can be made as shown in one piece with an aperture 6 provided symmetrically about a vertical plane of symmetry 7 and located in the part of the foam frame 4 which is closer to the rear end S of the seat cushion in the situation of use. The aperture 6 is through-going in the shown embodiment, but an embodiment with an aperture made as a blind hole is possible as well. The foam frame 4 may be constituted by latex foam or any other type of foam used for padding in seat cushions.

The disposition of the aperture 6 and the elements 5 is determined by the anato-my of the user; the area in which pressure sores are most frequent is under the seat bones whereas the area under the thighs can suffice with the soft support of resilient foam.

It appears on Figs. 1 and 2 that the liquid-containing elements 5 have a height which is less than the height of the foam frame 4 along the rim of the aperture 6.

The difference in height can vary but may be between 10 and 30 mm, preferably mm. One reason for this difference is that the support provided by the ele-ments 5 can be adjusted according to the need of the user. Such an adjustment can be provided by using an insert 9, made e.g. of a hard type of foam, which is placed at the side of an element 5 facing the bottom 2. By using inserts of varying height, the height of each individual liquid-containing element 5 can be adjusted.

In Fig. 1 only one insert 9 is used; it is of course possible to use inserts 9 under both elements S so as to elevate the elements evenly. Each insert 9 can be pro-vided with parallel top and bottom sides, or may be provided with a tapering top and bottom sides so as to elevate one end of the liquid-containing element 5 more than the other end.

The liquid-containing elements 5 are provided as independent units, see also Fig. 4, which are closed containers.. The element S is made of pieces of material, preferably of the kind of plastic or plastic-coated canvas used for waterbeds, which are joined along the edges 13 by welding in a way known per se. The ele- ments 5 can be filled with tap water provided with an agent for suppressing bac-terial and algae growth. In order to prevent sloshing movements of the water, it is preferred to have a sponge-like insert 10 made of foam rubber in each element 5; the sponge-like insert 10 also imparts a well-defined shape of the element 5.

The sponge-like insert provides a gel-like feel to the user when seated on the seat cushion, meaning that the liquid-containing elements are slowly adapting to the pressure from the user's buttocks.

A filling opening 11 with closure designed as those of waterbeds is provided in each element, and in order to accommodate for the closure, the insert 10 can be provided with a cutout 12. In use, the filling opening 11 is turned towards the bottom side 2 of the element S so that it is not sensed by the user sitting on the seat cushion.

The seat cushion according to the invention may be supplemented by some kind of insulating material, especially over the liquid-containing elements 5, in order to prevent a cold feeling on the user's skin caused by the liquid in the elements 5.

Other embodiments of the seat cushion according to the invention are possible.

For example, three or more liquid-containing elements can be used in the seat cushion according to the invention. Instead of a sponge insert in each liquid-containing element, the movements of the liquid could be constrained by using a gel or a viscous liquid in the element. The liquid could be a substance other than water. Also, it is noted that the application of one instead of two liquid-containing elements in the aperture in the foam frame is within the scope of the invention.

Such single liquid-containing elements may be designed with a partitioning, e.g. along the plane of symmetry of the seat cushion, thus forming two distinct cham-bers in the element. A further variant of a single liquid-containing element will be to provide the mentioned partitioning with a passage, e.g. a valve or other flow-constraining means that may impede movement of the liquid from one chamber to the other.

Claims

CLAIMS1. A seat cushion, particularly for physically disabled persons, including a padding combining a foam material and at least one liquid-containing element, character-ised in that the at least one liquid-containing element is a self-contained unit which is spaced apart from lateral sides of the seat padding, and wherein foam material is provided around the liquid-containing element or elements along lat-eral sides of the padding.
2. A seat cushion according to claim 1, wherein the foam material is provided as a continuous foam frame surrounding an aperture for receiving liquid-containing elements.
3. A seat cushion according to claim 2, wherein the foam frame has a constant height around the central aperture and wherein the liquid-containing element or elements have a height which is less than the height of the foam frame.
4. A seat cushion according to claim 3, wherein the difference in height between foam frame and element is between 10 and 30 mm.
5. A seat cushion according any preceding claim, including two liquid-containing elements arranged juxtaposed side by side at respective sides of a vertical plane of symmetry of the seat cushion.
6. A seat cushion according to claim 5, wherein the two liquid-containing elements are separately adjustable in height relative to the foam material, the adjustment provided by changing one or more inserts located under the liquid-containing el-ements.
7. A seat cushion according to any preceding claim, including a liquid-containing element which is divided into two internal compartments by a partitioning extend-ing along a vertical plane of symmetry of the seat cushion, wherein a passage is arranged in the partitioning for providing or controlling fluid communication be-tween the compartments.
8. A seat cushion according to any preceding claim, wherein each liquid-containing element is filled with aqueous fluid, and wherein another foam material is provided in each liquid-containing element for distending the element.
9. A seat cushion according to claim 8, wherein the aqueous fluid contains a bac-tericide and/or an algaecide.
10. A seat cushion according to any of claims 1 -7, wherein the liquid-containing elements contain a viscous fluid or an aqueous gel.
11. A seat cushion according to any preceding claim, wherein the liquid-containing element/elements is/are exchangeable.
12. A seat cushion according to any preceding claim, including a cover enclosing the padding, the cover provided with a friction-enhancing part at a side intended for contact with an underlying base.
13. A seat comprising a seat cushion according to any preceding claim.
14. A wheelchair including a seat cushion according to any of claims 1 -12.