Pneumatic Structure

Abstract

A pneumatic structure for sitting, lying and reclining cushions including a plurality of cells disposed together in rows and frictionally interconnected at a plurality of sides along a transversal web thereby forming a layer, the layer being charged with compressed gas through at least one valve and made from a membrane of flexible, gas-tight material. The structure displays a plurality of frictionally interconnected layers, the layers being interconnected such that a longitudinal web separating the layers is present. A casing made from flexible, elastic material is present and envelops the plurality of layers. The casing is frictionally connected partly or across a full length of a contact line to at least one cell.

Description

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a pneumatic structure for use, for example, as sitting, lying and reclining cushions.

2. History of Related Art

Pneumatic sitting and reclining cushions are known in the art. They usually comprise a plurality of communicating air tubes disposed alongside one another in a row, which can be inflated and deflated via a common valve and therefore resemble the airbed known in the art both in structure and form. A degree of scope for adaptation exists through the potential for giving individual tubes different air pressures or using different diameter tubes, whereby the shape and softness can be varied to a limited extent. For practical application, such cushions are also provided with a fabric cover. However, the basic structure of the tubes remains visible and, as is essential to a cushion, palpable too. An example of a pneumatic sitting cushion is disclosed in WO 94/07396.

SUMMARY OF THE INVENTION

The object of the invention is to create a pneumatic structure, in particular for sitting, lying and reclining cushions, which offers good malleability, is able to meet stringent requirements in relation to sitting comfort, can offer an appreciable weight saving compared with conventional foam cushions and can be effectively combined with rigid structures. In particular, despite the great scope offered in shape design possibilities, the structure should not become stiff or even hard, as invariably seems to be the case when using many structural webs.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the pneumatic structure of the present invention may be obtained by reference to the following Detailed Description, when taken in conjunction with the accompanying Drawings, wherein:

FIGS. 1 a,b show a schematic diagram of a first exemplary embodiment in longitudinal and cross-section;

FIG. 2 shows a schematic diagram of a second exemplary embodiment in cross-section;

FIG. 3 shows a schematic diagram of a third exemplary embodiment in cross-section;

FIG. 4 shows a schematic diagram of a fourth exemplary embodiment in cross-section;

FIG. 5 shows a schematic diagram of a fifth exemplary embodiment in cross-section;

FIGS. 6 a,b show a schematic diagram of a sixth exemplary embodiment in longitudinal and cross-section;

FIG. 7 shows a schematic diagram of a seventh exemplary embodiment in cross-section; and

FIG. 8 shows a schematic diagram of an eighth exemplary embodiment in cross-section.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic diagram of a first exemplary embodiment of a pneumatic structure 1 according to the invention in cross-section. Unlike single-layer structures, as are commonly found in airbeds and pneumatic seat cushions, the pneumatic structure 1 comprises at least two layers 3 of gas-filled cells 2 disposed in a row. The cells 2 are, for example, tubular. The structure is made from a flexible, gas-tight membrane 5. This membrane 5 preferably comprises a suitable plastic film. The cells 2 may be produced, for example, by heat-sealing or gluing elastic PU films. The cells 2 are connected along part of their periphery to the adjacent cells 2, thereby forming parts of transversal webs 7 and longitudinal webs 8. These webs 7,8 are formed, for example, by heat-sealing or gluing together adjacent membranes 5 or by ensuring that adjacent cells 2 close to the webs 7,8 share a single common membrane 5. A cell 2 not lying at the edge of a layer 3 within the structure 1 therefore has at least three adjacent cells 2, namely, the two adjacent cells 2 on the same layer 3 to the left and right, and also one or several adjacent cells 2 in an upper and/or lower layer 3′. Communicating cells 2 that are under the same pressure (what this means both here and elsewhere in the text is overpressure relative to the ambient atmospheric pressure) form one or more groups 12 of cells 2, each with at least one valve 4 that serves to charge the individual cell 2 or group 12 of cells 2 with a compressed gas. In the first exemplary embodiment, four cells 2 in each case meet along a line 6 running in a longitudinal direction. The heat-sealed or shared membranes 5 of the cells 2 form the shape-stabilising webs 7,8, namely, a plurality of transversal webs 7 running vertically in the figure, and a longitudinal web 8 running horizontally in the figure.

FIG. 1 b shows the first exemplary embodiment in the longitudinal section A-A′. The cells 2 are not individually heat-sealed at both ends, but each layer 3 has a gas-tight connection across its entire width with an edge membrane 9 sealing the layer 3, wherein this edge membrane 9 may certainly also be formed by part of the membrane 5. The openings thereby produced at the ends of the cells 2 enable the pressure to be equalised between the cells 2 throughout the entire layer 3. The multi-layer body, created by the layers 3 of cells 2, is in turn surrounded by an all-enveloping casing 10, comprising a flexible, elastic membrane. The contact lines 11 of the convex cells 2 running longitudinally through the structure 1 may be frictionally connected partly or across their full length to the casing 10, for instance, heat-sealed or glued. In actual fact, the contact line 11 will always be a contact surface. The contact line 11 preferably runs essentially along the longitudinal axis of symmetry of this contact surface. If the casing 10 is additionally prestressed, this gives the pneumatic structure 1 a smooth surface, without the tubular cells 2 emerging as bulges. The combination of several layers 3, 3′ of cells 2 enables there to be significantly improved control of the shape of the pneumatic structure 1, than if the structure 1 were to have continuous cells 3 across its entire height. By reducing the radii of the cells 2, the tension in the membrane 5 of the cells 2 diminishes based on the same pressurisation. This facilitates a smooth, even surface and shape of the pneumatic structure 1, by means of the prestressed casing 10 connected to the cells 2 punctiformly or over the entire length. The structure 1 is made softer by a plurality of smaller cells 2, than if only a small number of larger cells 2 were present. The prestressing of the casing 10 can be achieved by selecting the gap 11-11′ between two contact lines 11 such that it is, for example, 1-20% smaller in the depressurised state than in the pressurised state. In other words, the casing 10 is stretched and expanded when the cells 2 are pressurised between the contact lines 11-11′. The structure 1 facilitates, for example when used as a sitting or lying cushion, a high degree of dimensional stability and malleability combined with a high standard of comfort and softness. This means that structure 1 need not be inflated until it is as hard as a board, in order for it to assume and maintain the desired shape.

FIG. 2 shows a three-layered pneumatic structure 1 schematically in cross-section as the second exemplary embodiment. According to the invention, three or more layers 3 of cells 2 must be combined. In this example, as in the preceding ones, the cells 2 of a layer 3 are interconnected by ducts or openings in the common transverse and longitudinal webs 7,8 and they display the same pressure.

FIG. 3 shows a third exemplary embodiment, once again with three layers 3 of cells 2, wherein, however, the layer 3′ does not extend over the entire width of the structure 1. Moreover, this structure 1 displays the same gas pressure in all cells 2. A single valve 4 is sufficient to charge the intercommunicating cells 2 with compressed gas.

FIG. 4 shows a fourth exemplary embodiment. This is a variant of the first exemplary embodiment. The transversal webs 7 in the first layer 3 are not directly connected to the transversal webs 7 in the second layer 3′. A cell 2, which does lie at the edge of a layer 3, is adjacent to at least four cells 2, namely, two cells 2 in the same layer 3 and at least two cells in an adjacent layer 3.

FIG. 5 shows a fifth exemplary embodiment of a pneumatic structure 1 according to the invention, which displays three different pressure regimes with pressures p1, p2, p3. The groups 12 of communicating cells 2 with the same pressure are interconnected by means of openings or ducts 13 in the transversal webs 7 and longitudinal webs 8.

Means exist for the pressurisation of the groups 12, such as, for example, compressors, pressure sensors, electronic controls, valves, pressure lines. Such means are known to the person skilled in the art and need not therefore be dealt with in further detail.

FIGS. 6 a,b show a sixth exemplary embodiment.

The schematic cross-section in FIG. 6a shows the cells 2 in this example sealed such that they are gas-tight relative to one another. Each individual cell 2 has at least one separate valve 4 and can be pressurised independently of the other cells 2. The longitudinal section B-B′ in FIG. 6b clearly discloses that the transversal webs 7 in this exemplary embodiment leave no opening free at the ends of the tubular cells 2. The edge membrane 9 seals off each cell 2 individually, so that no gas exchange can take place between the cells 2 within a layer 3.

FIG. 7 shows a seventh exemplary embodiment with an irregular, asymmetric configuration and size of the cells 2. By varying the shape, size, configuration and number of cells 2, the person skilled in the art can produce pneumatic structures of the most divergent shape and firmness.

FIG. 8 shows an eighth exemplary embodiment. The casing 10, the membrane 5, the transversal webs 7 and the longitudinal webs 8 are provided at some points with fluid muscles 14. FIG. 8 shows, for example, possible configurations, combinations and positions of such fluid muscles 14, which may be shortened in length. The fluid muscles 14 are linear actuators that shorten the webs 7,8 or, more generally, the membrane 5 of the cells 2 and also the casing 10 at any point and are thereby able to alter the shape of the structure. The fluid muscle 14 comprises, for example, tubular, fluid-tight chambers, which are integrated in the membrane 5 or casing 10 to be shortened. When these chambers are charged with a fluid—for example, compressed air—which is under greater pressure than the surrounding cells 2, the chambers become essentially round in cross-section. Fluid muscles 14 of this type and the means required for their operation, such as lines, compressors and controls, are known to the person skilled in the art. They will not therefore be dealt with further here.

The cell 2′ is limited as an example of double-walled webs 7,8. A multi-layer structure for the webs 7,8 can be achieved with all the aforementioned exemplary embodiments, for example by gluing or heat-sealing the membrane 5. With the remaining webs 7,8, the chamber of the fluid muscle 14 is formed by a piece of membrane secured at its edges in a fluid-tight manner to the web 7,8 and by part of the web 7,8 itself.

Included in the concept of the invention is the possibility of combining the different features of the aforementioned exemplary embodiments arbitrarily, in order to obtain further exemplary embodiments according to the invention.

Claims

1. A pneumatic structure for sitting, lying and reclining cushions, comprising. a plurality of cells disposed together in rows, the plurality of cells being frictionally interconnected at the sides along a transversal web thereby forming a layer charged with compressed gas through at least one valve made from a membrane of flexible, gas-tight materials; wherein the structure displays a plurality of frictionally interconnected layers; wherein the frictionally interconnected layers are interconnected such that a longitudinal web separating the frictionally interconnected layers is present; a casing made from flexible, elastic material is present and envelops the frictionally interconnected layers; and wherein the casing is frictionally connected partly or across full length of a contact line to at least one cell of the plurality of cells.

2. The pneumatic structure according to claim 1, wherein the plurality of cells and the casing are produced by gluing and/or heat-sealing plastic film.

3. The pneumatic structure according to claim 1, wherein the transversal webs of the frictionally interconnected layers each meet in pairs on line on the longitudinal web to form a transversal web that passes through the entire structure.

4. The pneumatic structure according to claim 1, wherein at least one layer does not extend over an entire width and/or length of the structure.

5. The pneumatic structure according to claim 1, wherein the structure comprises at least two groups of communicating cells, wherein the at least two groups of communicating cells can be charged with different pressures.

6. The pneumatic structure according to claim 1, wherein two edge membranes create a gas-tight seal at the ends of at least two cells of the plurality of cells, wherein the transversal webs of the at least two cells connected by the edge membranes are not connected to the edge membranes and consequently forming an opening for pressure equalisation between the at least two connected cells.

7. The pneumatic structure according to claim 6, wherein the pressure equalisation between the at least two connected cells of the same pressure is made possible by means of openings or ducts in the transversal webs and/or the longitudinal webs.

8. The pneumatic structure according to claim 1, wherein each cell of the plurality of cells adjacent to the casing is frictionally connected to the casing either partly or along the full length of the contact line.

9. The pneumatic structure according to claim 1, wherein a size of the casing is selected such that when the structure is pressurised, the structure is stretched more than the membrane, wherein a peripheral length of the casing is smaller when it is not stretched than the peripheral length of pressurised layers without the casing.

10. The pneumatic structure according-to claim 1, wherein a gap between two adjacent contact lines is shorter when the structure is not pressurised, and the casing is not stretched, than the gap between the contact lines on the plurality of cells when the structure is pressurised without the casing.

11. The pneumatic structure according to claim 1, wherein the membrane and/or the casing have at least one fluid muscle and means of operating the fluid muscles.

12. The pneumatic structure according to claim 1, wherein the membrane is made from elastic material.