Volume-flexible body

Abstract

A volume-flexible body that can be filled with fluid including sheets preferably welded along the circumferential edges made preferably of synthetic material whereby the sheets form additionally a hinged section along which the sheets are folded forming at least two sections of the inflatable body lying partially on top of one another, and whereby a conduit is formed extending at least through the hinged area between the two sections of the fillable body. At least one element (7, 9) is provided in the length of the conduit (4), which keeps the plastic sheets at a distance apart across at least a part of the width of the conduit (4) even in the deflated condition of the body (K) to decrease the flow resistance between the sections of the body as much as possible and to guarantee a simple and smooth fluid exchange even at a small pressure difference.

Description

BACKGROUND OF THE INVENTION

The invention relates to a volume-flexible body that can be filled with fluid including sheets preferably welded along the circumferential edges made preferably of synthetic material whereby the sheets form additionally a hinged section along which the sheets are folded forming at least two sections of the inflatable body lying partially on top of one another, and whereby a conduit is formed extending at least through the hinged area between the two sections of the fillable body.

THE PRIOR ART

A body of this type is exemplary disclosed in DE 203 07 1633 U1 as a support cushion for a motor vehicle seat. The described support cushion includes two cushion elements which are connected to one another at the edge by a common hinge and which are placed on top of each other, at least partially, in their use. The hinge can be made thereby of the sheet material forming the cushion element whereby fluid communication can be provided between the two cushion elements by means of the hinge or a connecting conduit according to the invention. The connecting conduit can be formed by the sheet section which additionally connects the two cushion elements to the hinge.

In the area of the hinge and/or in the area of the separate conduit, which is curved at a small radius in the same manner as the hinge, there is created a tensile stress within the outer sheet while a compressive strain is created within the inner sheet. This has the result that the sheets are pressed against each other with a relatively strong force. The connecting conduit has therefore a high resistance relative to the flow of fluid, which represents a very negative effect especially during filling or emptying via a single fluid supply element as well as for pressure compensation between the two cushion elements. The contact pressure of the sheets can only be overcome with a specific interior pressure; however, a relatively rapid and almost shock-like fluid exchange takes place in this case. To this end, complete emptying of the body is almost impossible since resistance of the connecting conduit cannot be overcome below a certain residual pressure. Proper functioning is thereby not guaranteed in such cases.

It was therefore the object of the invention to design a body of the aforementioned type in such a manner that the flow resistance between the sections of the body is reduced as much as possible and whereby a simple and smooth fluid exchange is guaranteed between the sections even at low pressure differences.

SUMMARY OF THE INVENTION

For the achievement of this object, the cushion body is characterized in that there is provided at least one element within the length of the conduit which keeps the sheets apart across at least a part of the width of the conduit in the deflated condition of the body. The fluid connection between the sections of the body is always kept open thereby, even in the case of a highly curved or buckled hinge or in the case of a separate conduit. A body designed in this manner offers smooth pressure compensation and a smooth fluid exchange between its sections and makes possible smooth and even filling as well as complete emptying by means of only one fluid supply element during the filling process and the complete emptying process.

The body is additionally characterized according to the invention in that the conduit is laterally defined by the welding beads created during the joining of the sheets whereby the welding beads maintain a space between the sheets at least in the close vicinity thereof. A smooth fluid exchange can be guaranteed at any time in a simple manner already during the course of manufacturing of the body and its sections.

In case of sheet materials whereby only less distinctly formed welding beads are created, it can be achieved through special manufacturing steps that welding beads are formed in a thicker manner than needed for a secure bond between the sheets lying on top of one another.

To keep open even larger cross sections of the conduit for the fluid exchange, according a further advantageous embodiment additional welding beads, extending essentially in longitudinal direction of the conduit, are provided between the existing welding beads laterally defining the conduit.

In the case where there are no welding beads created, based on the type of the employed material and/or based on the type of manufacturing process, there is at least one spacer element inserted into the conduit according to another inventive embodiment of the fillable body to keep the conduit open in any condition for the fluid exchange between the sections.

The spacer element can thereby be formed by an additional piece of sheeting inserted between the sheet sections forming the conduit whereby the piece of sheeting has slots or grooves extending in longitudinal direction of the conduit and whereby its edges keep the sheets at a distance apart from one another so that fluid exchange is ensured thereby. Joining of the sides of the slots or grooves to each other can be an advantage in manufacturing and for the stability of the spacer element.

Another spacer element is proposed having a similar effect as the welding bead extending in longitudinal direction of the conduit, which is formed by a narrow piece extending essentially in longitudinal direction of the conduit as well.

Alternatively thereto, at least one spacer element can be inserted into the conduit whereby the spacer element is made of permeable material according to an additional characteristic of the invention. For example, conceivable would be elements made of foam, porous materials, preferably synthetic materials, or woven or interlaced material inserted between the plastic sheets.

It is proposed according to an additional advantageous embodiment of the invention that one sheet defining the body, preferably the sheet lying at the outer side after the folding of the body, is wider at least in the area of the conduit than the opposed sheet which forms one or a plurality of arches for the formation of one or all conduits. The excess width of the wider sheet material, as compared to the narrower sheet, can be considered as the additional element. This difference in width leads to the fact that the sheets are not pressed against one another during folding or bending of the connecting area. The formation of waves can possibly occur in the wider sheet—in this case, a plurality of juxtaposed conduits are created remaining open at all times. The formation of arches or waves in the wider sheets can be enhanced through the careful use of a tool to manufacture the body.

It can be proposed as an additional characteristic in the case of wave formation of the wider sheet that additional welding beads are provided between each pair of the multiple arches. The arches improve the open position of the parallel conduits whereby the arches keep the sheets at a distance apart at the vicinity of the welding bead.

The invention is described in more detail in the following description with the aid of embodiment examples illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a support cushion for a vehicle seat consisting of two folded sheets forming a bubble as an example of a body that can be filled with fluid;

FIG. 2 is an illustration of the bubble made of plastic sheeting of FIG. 1 in an unfolded condition;

FIG. 3 shows a detail of the curved conduit between the two sections of a cushion body similar to the one in FIG. 1 and FIG. 2;

FIG. 4 shows a detail of a conduit in the unfolded condition;

FIG. 5 is an illustration of the conduit of FIG. 4 in a curved condition similar to FIG. 3; and

FIGS. 6a and 6b show cross sections in the region of the conduit as an additional embodiment of the cushion body according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a volume-flexible body K that can be filled with fluid in the shape of a curved bubble or similar support cushion for installation into vehicle seats whereby the body K consists of two opposed sheets preferably welded together along the circumferential edge and made preferably of synthetic material. The sheets form two sections 2, 3 lying on top of one another of the inflatable body K through folding along a hinged area 1 whereby a transverse conduit 4 is formed by the sheets at least in the hinged area 1 between the two sections 2, 3 of the fillable body K. Additional straps 5 in the hinged area 1 can fix the position of the sections 2, 3 against one another. The upper section 2 and also the lower section 3 of the body together with its conduit 4 is filled and emptied as well by means of a fluid supply element 6, preferably one made for compressed air.

The joining of the sheets of body K lying on top of one another is performed in the illustrated example by welding under the formation of a circumferential welding bead 7, which also laterally defines the conduit 4. The welding bead 7 is formed through displacement of the sheet material.

The conduit 4 is highly curved in the position of the body K shown in FIG. 1 so that the sheets are pressed against one another with a relatively strong force based on the tensile stress within the outer sheet and the compressive strain within the inner sheet. The distance between the sheets increases with the formation of the welding bead 7 at the edge of the conduit 4. The sheets are also kept at a distance apart directly adjacent to the welding beads 7 and thereby across at least a part of the width of the conduit 4 whereby the cross sections 8 of the conduit 4 are also kept open even in a buckled or highly curved condition. The fluid connection between the sections 2, 3 of the body K is thereby always kept open.

Welding beads 7 can possibly be formed thicker than needed for a secure bond of the sheets lying on top of one another. This can be performed by means of a suitable shaped tool or through excessive pressure between the sheets to be bonded during the welding process together with a distinctively tooled shape immediately in front of the welding edge so that the sheets can form here the open cross section 8 of the conduit 4.

Additional welding beads can possibly be provided disposed essentially parallel to the welding beads 7 near the edge and extending essentially in longitudinal direction of the conduit 4.

Another embodiment is illustrated in FIG. 4 and FIG. 5 wherein a piece of sheet material 9, serving as a spacer, is inserted into the conduit 4. This spacer 9 is inserted between the sheets forming the body K and it can be fixed in a traditional manner. The piece of sheet 9 is provided with slots 10 extending in longitudinal direction of the conduit 4 to improve the flow in the conduit.

A design is schematically illustrated in a cross-sectional view in FIG. 6a wherein the outer sheet if of greater width than the lower sheet after folding of the body (K). This effect can be achieved by using materials of different width from the beginning or by pushing the material together during the welding process. The wider sheet forms thereby a least one arch 11 and forms thereby also the conduit 4, which is kept open even during complete folding of the connection area of the sections 2, 3 of the body K.

The formation of a plurality of arches 1 or waves is possible as it is shown in the example of FIG. 6b. Several parallel conduits 4a are formed thereby between said arches 11 along the width of the connection area defined by the welding beads 7. Additional welding beads 7a can be provided between each pair of arches 11 to fix the arches 11 and to securely keep the conduits 4a open.

Claims

1. A volume-flexible body that can be filled with fluid consisting of sheets preferably welded along the circumferential edges made preferably of synthetic material whereby said sheets form additionally a hinged section along which the sheets are folded forming at least two sections of the inflatable body lying partially on top of one another, and whereby a conduit is formed extending at least through the hinged area between the two sections of the fillable body, characterized in that there is provided at least one element (7, 9, 11) within the length of the conduit (4) which keeps the sheets apart across at least a part of the width of the conduit (4) in the deflated condition of the body (K).

2. A body according to claim 1, wherein the conduit (4) is laterally defined by the welding beads (7) created during the joining of the sheets and whereby said welding beads (7) maintain a space between the sheets at least in the close vicinity (8) thereof.

3. A body according to claim 2, wherein welding beads (7) are formed in a thicker manner than needed for a secure bond between the sheets lying on top of one another.

4. A body according to claim 3, wherein additional welding beads, extending essentially in longitudinal direction of the conduit (4), are provided between the existing welding beads (7) laterally defining the conduit (4).

5. A body according to claim 1, wherein at least one spacer element (9) is inserted into the conduit (4).

6. A body according to claim 5, wherein said spacer element can be formed with an additional piece of sheeting (9) inserted between the sheet sections forming the conduit (4) and whereby said piece of sheeting has slots (10) or grooves extending in longitudinal direction of said conduit.

7. A body according to claim 5, wherein a spacer element is formed by a narrow body extending essentially in longitudinal direction of the conduit (4).

8. A body according to claim 5, wherein at least one spacer element made of permeable material is inserted into the conduit (4).

9. A body according to claim 1, wherein one sheet defining the body (K), preferably the sheet lying at the outer side after the folding of the body (K), is wider at least in the area of the conduit (4) than the opposed sheet which forms one or a plurality of arches (11) for the formation of one or all conduits (4, 4a).

10. A body according to claim 9, wherein additional welding beads (7a) are provided between each pair of the multiple arches (11).