Fluid fillable, variable volume chamber

The invention relates to a fluid-fillable, volume-variable body, consisting of two superimposed, preferably welded foils, preferably made of plastic material, connected to one another along the circumferential edge, which foils also form a hinge area, along which hinge area the foils to form two at least partially superimposed partial areas of the inflatable Body are folded, and wherein the foils form at least one connecting channel, which if necessary traverses the hinge area, between the two partial areas of the fillable body.

Such a body is disclosed, for example, as a support cushion for a motor vehicle seat in DE 203 07 633 U1. The support cushion described consists of two cushion elements, which are connected at the edge via a common hinge and, when in use, come to lie at least partially on top of one another. The hinge can be formed by the foils forming the cushion elements, whereby, according to a described embodiment, a fluid connection between the two cushion elements can be provided by the hinge or by a connecting channel formed by film areas which the two cushion elements in addition to the hinge with each other associate.

In the area of ​​the hinge and / or a separate connecting channel bent in the same way with a small radius, tensile stress is created in the outer film, while compressive stress is built up in the inner film. This has the consequence that the foils are pressed against one another with a relatively high force. The connecting channel thus offers a high resistance to the overflow of the fluid, which has a very negative effect, especially when filling or emptying via a single fluid connection, but also to compensate for the two cushion elements. The contact pressure of the foils can only be overcome above a certain internal pressure, but then a relatively quick, almost shock-like fluid exchange takes place. Completely emptying the body, however, is almost impossible because below a certain residual pressure the resistance of the connecting channel can no longer be overcome. Correct functioning is therefore not guaranteed in such cases.

It was therefore the object of the present invention to design a body of the type specified at the beginning in such a way that the overflow resistance between the subregions of the body is reduced as much as possible and a simple and smooth fluid exchange between them

Sub-areas is reliably guaranteed even with a small pressure difference.

To solve this problem, the body is characterized in that at least one element is provided in the course of the connecting channel, which keeps the foils spaced apart over at least part of the width of the connecting channel even in the deflated state of the body. In this way, the fluid connection between the partial areas of the body is always kept open, even if the hinge or the connection channel is severely bent or kinked. A body designed in this way offers a soft pressure equalization and fluid exchange between its subregions, and enables soft and uniform filling and complete emptying even during filling and emptying by means of a fluid connection alone.

According to an advantageous embodiment, the body according to the invention is further characterized in that the connecting channel is laterally bounded by the welding beads produced when the foils are connected, which welding beads maintain a distance between the foils at least in the immediate vicinity. In this way, the smooth exchange of fluid can be ensured at all times in a simple manner in the course of the manufacture of the body and its subregions.

In the case of film materials in which only slightly pronounced weld beads are produced, special production steps can be used to ensure that the weld beads are made thicker than is necessary for the secure connection of the foils lying one on top of the other.

In order to keep open even larger cross-sections in the connecting channel for the fluid exchange, it can be provided according to a further advantageous embodiment that between the

Connecting channel laterally delimiting welding beads, further welding beads are provided essentially in the longitudinal direction of the connecting channel.

In the event that the materials and / or manufacturing processes used do not result in a weld bead, according to another embodiment of the fillable body according to the invention, at least one spacer element is used in the connecting channel to protect the

Connection channel in every state of the body for the fluid exchange between the parts

AT 412 863 books to be kept open.

The spacer element can be formed by an additional piece of film inserted between the film sections forming the connecting channel with slots or grooves extending in the longitudinal direction of the connecting channel, along the edges of which the films are kept spaced from one another and thus the fluid exchange is ensured. A connection of the slot or groove walls to one another can be advantageous for the manufacture and also for the stability of the spacer element.

A similar effect as in the case of welding beads provided in the longitudinal direction of the connecting channel is given for a spacer element according to the invention, which is formed by a narrow body extending essentially in the longitudinal direction of the connecting channel.

Alternatively, according to a further feature of the invention, at least one spacer element made of fluid-permeable material can also be used in the connecting channel. For example, elements using foam, elements made of porous materials, preferably plastics, or woven or knitted fabrics inserted between the foils would be conceivable.

According to a further advantageous embodiment of the invention it is provided that one of the foils delimiting the body, preferably the foil lying on the outside when the body is folded, at least in the area of ​​the connecting channel has a greater width than the opposite foil and one or each connecting channel to form the or each connecting channel forms several bulges. The excess width of the wider film compared to the narrower film can be viewed as an additional element here. This difference in width means that the foils are no longer pressed against one another when the connection area is bent or bent. If necessary, waves can form in the wider film, in which case several adjacent, always open connecting channels arise. The formation of bulges or Waves in the wider film can be favored by taking precautions in the tool for making the body.

Advantageously, in the case of corrugation of the wider film, it can be provided as an additional feature that additional welding beads are provided between each two of several bulges. These facilitate keeping the parallel connecting channels open by keeping the foils spaced apart in the vicinity of the welding beads.

In the following description, the invention is to be explained in more detail with reference to the exemplary embodiments shown in the accompanying drawings.

1 shows a support cushion for a vehicle seat, consisting of a folded-up double film bladder, as an example of a body that can be filled with fluid, FIG. 2 is an illustration of FIG

1 in the unfolded state, FIG. 3 shows a detail of a curved connecting channel between two subregions of a body similar to FIGS. 1 and 2, FIG. 4 shows a detail of a connecting channel in the unfolded state, FIG. 5 is an illustration of the connecting channel of FIG. 4 in a curved state, similar to FIG. 3, and FIGS. 6a and 6b show cross sections in the area of ​​the connecting channel for a further embodiment of the body according to the invention.

Fig. 1 shows a fluid-fillable, volume-variable body K according to the invention, such as a lordosis bladder or similar support cushion for installation in vehicle seats, which body K consists of two superimposed, preferably welded foils, preferably made of plastic material, connected to one another along the circumferential edge. By

When folded along a hinge area 1, the foils form two superimposed partial areas 2, 3 of the inflatable body K, the foils forming at least one connecting channel 4 between the two partial areas 2, 3 of the inflatable body K, which at most crosses the hinge area 1. In addition to the hinge area 1, further tabs 5 can fix the position of the sub-areas 2, 3 with respect to one another. Via a fluid supply connection 6, preferably for compressed air, the upper sub-area 2 and further via the connecting channel 4 also the lower sub-area 3 of the body is supplied and also emptied.

The connection of the superposed foils of the body K is achieved in the example shown by welding, forming a circumferential welding bead 7, which also delimits the connecting channel 4 at the side. This weld bead 7 is due to the displacement of the

Material of the foils formed.

AT 412 863 B

In the position of the body K shown in FIG. 1, the connecting channel 4 is strongly curved, so that due to the tensile stress in the outer film and the compressive stress in the inner film, these are pressed against one another with a relatively high force. In the area of ​​the welding beads 7 at the edge of the connecting channel 4, the distance between the foils increases when the welding beads 7 are formed, and these foils are kept immediately adjacent to these welding beads 7 and thus also spaced apart from one another over at least part of the width of the connecting channel 4, as a result of which the cross-sectional areas 8 of the connecting channel 4 can also be kept open in a kinked or strongly curved state. The fluid connection between the subregions 2, 3 of the body K is therefore always kept open.

In order to further improve this effect, the welding beads 7 can possibly be made thicker than is necessary for the secure connection of the foils lying one on top of the other. This can be achieved by a suitable tool shape, also by overpressure between the two foils to be connected during the welding process and a somewhat pronounced tool contour just before the welding edge, so that the foils can form the open cross-sectional area 8 of the connecting channel 4 here.

At most, further welding beads can be provided substantially parallel to the edge-side welding beads 7, substantially in the longitudinal direction of the connecting channel 4.

Another embodiment is shown in FIGS. 4 and 5, in which a piece of film 9 is used as a spacer in the connecting channel 4. This spacer element 9 is inserted between the foils forming the body K and can be fixed in a conventional manner. The film piece 9 has slots 10 extending in the longitudinal direction of the connecting channel 4 in order to improve the flow through the connecting channel 4.

In FIG. 6a, a construction is shown schematically in cross section, in which the film lying on the outside when the body (K) is folded has a greater width than the lower film.

This effect can be caused by different material widths from the beginning or by pushing together during the welding process. The wider film forms at least one bulge 11 and thereby forms the connecting channel 4, which is kept open even when the connecting area of ​​the partial areas 2, 3 of the body K is bent.

The formation of several bulges 11 or waves is also possible, as the example in FIG. 6b shows. Between these several bulges 11 along the width of the connecting area delimited by the welding beads 7, several parallel connecting channels 4a are thus formed. Advantageously, additional welding beads 7a can be provided between two bulges 11 to fix the bulges 11 and also to keep the connecting channels 4a open.