GB2214401A - Inflatable walking cushion - Google Patents

Description

A.- OF 53 758 Inflatable walkinq cushion 2 1440 1 z_ The invention relates

to an inflatable walking cushion, comprising a plurality of chambers of gas-tight material attached to one another and communicating witb one another by means of a main connecting line so as to permit pressure equalisation between the chambers, and means for securing the cushion to the foot of a user.

A walking cushion of this kind is described in South African Patent No. 95-5677, in which a plurality of chambers are combined in a metal frame to form a cushion and means for securing the frame to a user's footwear is provided on the frame; the individual chambers are connected to one another by means of a central connecting line so that pressure eaualisation between the chambers is possible.

In walking cushions of this kind it is generally essential to minimise the specific ground pressure of a person with the walking cushion strapped underneath the foot, whilst if any uneven stretches of ground are encountered, for example rocks or branches, an increase in the internal pressure in the individual chamber (caused by an increase in ground pressure at the point in cruestion) is supposed to be avoided. Walking cushions Of this kind are used particularly as a safety measure in mine chambers, for walkina over minefields and in general for soft and yielding terrain.

In the known walking cushion, pressure ecrualisation does indeed take place between the individual chambers when there is a locally caused increase in Dressure in an individual chamber because of the connection between the chambers, but the known construction has the disadvantage that there is a certain instability of the cushion as a result of the unrestricted communication between the quantities of gas in the cushion, particularly if the cushion has not yet been been fully inflated; furthermore, damage to only one chamber will result in the entire cushion becoming useless almost immediately. The known construction is also characterised by a comparatively large proportion of metal components, because of the frame required.

According to the invention there is provided an inflatable walking cushion comprising a plurality of chambers of gas- tight material attached to one another and communicating with one another by means of a main connecting line so as to permit pressure equalisation between the chambers, and means for securing the cushion to the foot of a user, wherein each chamber is connected to the main connecting line by means of at least two tie lines, each tie line containing a non-return valve, and each nonreturn valve acting in a different direction from the other.

The non-return valves mav act as pressure relief valves so as to permit gas flow only when a certain pressure difference across the valve is exceeded. There is the advantage that on the one hand, in the event of a local increase in pressure in one chamber, pressure equalisation will occur within a short time between the chambers by means of the non-return valves, but on the other hand, particularly if there is damage to only one chamber, the pressure equilibrium of the chambers will not be affected immediately, at least, since the nonreturn valves act as pressure relief valves for the flow of gas which occurs. In addition, because of the pressure relief function of the non-return 1 i 1 valves, the individual chambers are more stable in their relationship with one another, which means that the user will feel secure in walking even on a cushion which is not fullv inflated. AdvantaQeously, because of the simplicity of construction, mass-produced non-return valves can be used. In a preferred embodiment of the invention, a pressure relief valve is located in the main connecting line and when the cushion is filled or under extreme ambient conditions, for example when the external temperature is very high, this will prevent excessively high operatinq pressure from building up in the system of chambers of the cushion by venting to atmosphere.

According to one embodiment of the invention, the walking cushion consists of a textile casing subdivided into a plurality of chambers in which individual gas-tight bladders are then inserted which are in turn connected to the tie lines.

The casing has corresponding openings in the individual chambers for the insertion of the gas-tight bladders.

ConsecruentIv, the cushion can be collapsed to a very small volume.

Because of the advantageous design of the walking cushion it is also very easy to handle because, thanks to the improved stability, it is no longer necessary to use metal parts to impart shape to it; furthermore, all the connecting parts may be made of the sam.e inaterial as the gas-tight bladders themselves, so that no interfering rigid components are present. The individual chambers may also be stitched, stuck or in some other way connected to one another to form the walking cushion and, as already stated, this has advantaqes in the ease of handling and in the reduced weight of the walking cushion.

Moreover, flaps may be provided on the cushion in which it is possible to insert connecting and/or carrying elements, particularly with a view to additionally using the walking cushion as an amphibious means of transport or as a shock-absorbing support for the sick or injured, in which a plurality of walking cushions are combined by inserting rodlike elements or rifle barrels in the flaps of a plurality of cushions and thereby ioining them 10- together to form a larger unit.

Advantaqeously, textile and/or rubberised strips and/or stamped parts may be applied to the undersides of the chambers of the walkinq cushion in order to improve the non-slip crualities of the 15 cushion for all the possible applications.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which:- Fig. 1 is a diagrammatic view of a walking cushion according to the invention; and Fig. 2 is a partial plan view showing an individual chamber.

2555 The walkinq cushion 10 shown in Figure 1:ive individual chambers wh4 consists of 4 Lch are connected to one another in a manner not shown in detail but described hereinbefore, or are desianed to receive special gas-tight bladders. A plate 12 with straps 13 is mounted on the cushion 10, said straps 13 serving to secure the cushion 10 to the user's footwear. The plate 12 preferably consists of a plurality of rigid components connected to one another by hinge straps or the like. These hinge straps enable the plate to be folded down to a small package.

t i As shown in Figure 2 in detail, a hose-like main connecting line 14 runs centrally along the cushion 10, and from it two tie lines 15 branch off for each chamber 11, whilst tube connectors 16 are provided at the points of intersection between 5 the lines 14, 15. The tie lines 15 extend into -ry tubes 17 which pass into the interior curved ent of the chamber 11 at a reinforced area 18. Between the tie lines 15 and the entry tubes 17 are provided non-return valves 19, non- return valve 19a permitting the filling of the chamber 11 and non-return valve 19b enabling gas to escape from the chamber into the tube system 14, 15.

Although not shown in detail, a central pressure relief valve may also be provided in the connecting tube 14, to limit the operating pressure prevailing in the system.

When the walking cushion is in operation, the cushion 10 or chambers 11 are filled through the central connecting tube 14, usually by inflating with exhaled air; the non-return valves 19a allow the air to be blown into the individual chambers 11. Once the cushion 10 is inflated and if a local peak load now occurs in an individual chamber 11 during use, the non-return valve 19b associated with this chamber allows gas to pass out of the affected chamber and the gas is able to flow throuqh the connecting tube 14 to the other chambers 11 and pass into them through the non-return valves 19a. The pressure prevailing in the system 14, 15 acts as a regulator on the non-return valves 19. so that if a certain pressure difference is exceeded air is allowed out or in.

If, in a particular instance, a single chamber 11 is damaged, this has the effect of causing a pressure increase in the other chambers 11, in the system 10, 11 as a whole, so that gas flows into the damaged chamber 11, but at the same time the non-return valves 19 act as pressure relief valves, so that this process does not suddenly affect the useability of the cushion.- Since the non-return valves used operate by spring action, -In the one Ttav direction of flow the non-return valves act as pressure relief valves since the force of the non-return spring always has to be overcome in th.42.s direction, which amounts to a certain minimum pressure being established in the chamber or bladder before any flow of gas occurs. In the case of a leak, this means, according to the invention, that the flow of gas into the damaged chamber 11 or bladder can only occur if there is minimum Dressure prevailing in the chamber 11 from which the flow of gas is proceeding, which happens only when the cushion is subiected to continuous loading. Thus, for example, if the load is removed from the Tgalking cushillon, for example by raising the foot, there is no further flow of gas into the damaged chamber, since the non-return valve of the undamaged chambers, acting as a pressure relief valve in this direction of flow, will prevent the free flow of gas into the damaged chamber. As a result, the cushion will remain operational for a correspondingly longer time even if the cushion or Part of it has heen damaged.

In addition to the use of the walking cushion according to the invention for reducing the ground pressure of the user when walking on soft and yielding.he invention terrain and particularly on mined areas, t proposes the use of a walking cushion of this kind as a personal swimming aid, the two walkinq cushions k 1 1 1 i - 7 allocated to the user being combined to form a buoyant unit which supports the upper part of the body, by placing a rod-shaped element in flaps provided for this purpose on each-cushion. In the same way, it is also possible to combine a plurality of walking cushions according to the invention to form larger amphibious transport units. Finally, the invention also includes t-he use of a unit consisting of a plurality of walking cushions as a shock- absorbing support for sick or injured persons.

It will thus be seen that at least in its preferred forms the invention provides a walking cushion imiDroved in terms of the stability of the cushion and the individual chambers, wherein its effect is maintained at least temporarily even if one chamber is damaged, and finally wherein the ease of handling of the walking cushion is improved.

Tt is to be clearly understood that there are no particular features of the foregoing specification, or of any claims appended hereto, which are at present regarded as being essential to the performance of the present invention, and that any one or more of such features or combinations thereof may therefore be included in, added to, omitted from or deleted from any of such claims if and when amended during the prosecution of this application or in the filing or prosecution of any divisional application based thereon. Furthermore the manner in which any of such features of the siDecification or claims are described or defined may be amended, broadened or otherwise modified in any manner which falls within the knowlede of a person skilled in the relevant art for example so as to encompass either implicitly or explicitly, equivalents or generalisations thereof.

Claims (9)

1. An inflatable walking cushion comprising a plurality of chambers of gas-tight material attached to one another and communicating with one another by means of a main connecting line so as to permit p - ressure equalisation between the chambers, and means for securing the cushion to the foot of a user, wherein each chamber is connected to the main connecting line by means of at least two tie lines, each tie line containing a non-return valve, and each non-return valve acting in a different direction from the other.

2. A walking cushion as claimed in claim 1, wherein a pressure relief valve is included in the main connecting line.

3. A walking cushion as claimed in claim 1 or 2, wherein the chambers are directly attached to one another.

4. A walking cushion as claimed in claim 3, wherein the chambers are attached to one another by stitching or adhesive bonding.

5. A walking cushion as claiTned in claim 1 or 2, wherein sepaarate bladders of gas-tight material connected to the tie lines are inserted in the chambers of a unified casing.

6. A walking cushion as claimed in claim 5, wherein the main connecting line and the tie lines consist of the same material as the gas-tight bladders.

7. Use of a walking cushion as claimed in any of claims 1 to 6 as an amphibious means of transport, in which a plurality of such cushions are combined, 1 1 - 9 by means of connectinq elements insertable in flaps provided, to form a larger unit.

1 1

8. Use of a walking cushion as claimed in any of claims 1 to 6 as a personal swimming aid.

9. Use of a walking cushion as claimed in any of claims 1 to 6 as a shockabsorbing support for a sick or injured person, a plurality of cushions being combined, by means of connecting and carrying elements insertable in flaps provided, to form a larger unit.

io. An inflatable walking cushion substantially as hereinbefore described with reference to the accompanying drawings.

0 Published 1989 at The Patent Office, State House. 6671 High Holborn, LondonWClR4TP. Further copies maybe obtained from The Patent Offlace Sales Branch, St Mary Cray, Orpington. Kent BR5 aRD. Printed by Multiplex techniques ltd. St Mary Cray, Kent, Con. 1/87