DE1248282B - Edge connection for inflatable hollow bodies made of flexible and dense material - Google Patents

Description

Edge joint for inflatable hollow bodies made of flexible and dense Material The invention relates to the formation of the edge connection for inflatable Hollow bodies, in particular air mattresses, seat cushions and the like, in which the edges the hollow body additionally by means of strips glued to the inside of the hollow body are reinforced.

The usual method for producing such hollow bodies is to that two fabric cuttings coated on one side are placed one on top of the other in such a way that they fit together with the edge that the layer side come to lie on the inside and the fabric side on the outside, whereupon the seam layers according to one of the known processes, usually by means of a high-frequency field, are brought to weld.

It has now been found that with plastic-coated fabrics weld seams produced in this way under the peeling stress for opening and thus tend to leak. Due to the in the hollow body, especially when loaded, The prevailing overpressure occurs at the weld seam and subsequently cracking in the plastic layer causing the leakage.

In a known hollow body, which consists of two by vulcanization consists of interconnected foam rubber sheets, the internal pressure has that Endeavor to separate the wheels from each other so that the edge connection in inflated State is permanently under load. Other known edge connections relate to the gluing of rubber-covered fabrics, whereby when pressed together the rubber covering penetrates the fabric and acts as a binding agent.

But since the edge connections of the inflatable hollow body that has become known Made of rubber due to its natural stickiness or with the help of an adhesive is carried out over the entire surface to be connected first by applying pressure, while the lasting and intimate union only occurs in the course of the subsequent vulcanization occurs, must for articles made of plastic or plastic-coated Tissues which are known not to be vulcanizable, the areas to be connected in a manner known per se by seam welding, preferably by high frequency welding, be combined with one another in a separate operation. That's why they can Connection methods common in the manufacture of rubber articles of plastics are not used.

The present invention, however, relates to a improved edge connection for inflatable hollow bodies made of coated with weldable thermoplastics Fabric, in which on the inside of made with thermoplastics coated fabrics existing hollow body walls one or two thermoplastic Plastic strips at a short distance from the edge connection of the hollow body lying points are welded.

The edge connection according to the invention can be carried out in various ways will. The edge seam can be sealed by a single or a multi-part, preferably two-part, thermoplastic plastic film take place. Further the edge seam can be made of a one-part or multi-part thermoplastic plastic film be bridged, or it can be a two-part thermoplastic plastic film be arranged so that each edge of this thermoplastic plastic film with the edge of the hollow body is g-welded solitary.

This means that the two edges of the film are welded on at the same time the foil edges themselves on the upper and lower hollow body wall in one operation do not weld together, provision is made for a Insert polyethylene film, as it is known that this does not weld in the high-frequency field. The usage a polyethylene film is then in this case not required if the welded to the inside of the hollow body walls, the edge seam bridging strip made of a thermoplastic plastic film coated strips of fabric.

Because when folding this strip, the fabric sides lie on top of each other come, only the thermoplastic layer of the welded between the electrodes Strip with the thermoplastic layer of the respective hollow body wall.

In a further development of the basic principle according to the invention, a reinforced edge connection still found in that in the area of the edges of the hollow body a Y-shaped profile strip, preferably injection-molded from soft polyvinyl chloride is welded on the inside of the hollow body walls and in the edge seam.

To explain the edge connection according to the invention there are a few Embodiments shown in the drawing.

1 shows a partial section through an inflated hollow body (Air mattress) in the previous embodiment; F i g. 2 shows the same section in the embodiment according to the invention; F i g. 3 shows a partial section of the edge of the hollow body when laid flat; 4 to 6 and 7 to 8 show the individual phases the manufacturing process of two embodiments of the edge connection; Fig. 9 and 10 show two further embodiments in partial section of the flattened edge of the hollow body the edge connection.

As in Fig. 1 of the previous embodiment can be seen, act the forces P on the weld seam 10 in the sense of a separation of the two thermoplastic Plastic layers by peeling effect. Such a stress is mostly the thin thermoplastic layer cannot grow when high forces occur, and the thermoplastic tears at the inner edge of the weld seam Plastic layer.

In Figures 2 and 3, the two form with thermoplastics coated fabric 1 and 2 the hollow body walls, the thermoplastic plastic layer comes to lie inside. In the course of production, as shown in FIG. 3 shown, a thermoplastic plastic film 3 in the folded state between the coated Fabrics 1 and 2 inserted so that the latter still protrude a little. In the folded A polyethylene film 4 is inserted into strips of the thermoplastic plastic film 3. The film strip 3 can now be welded to the outer walls 1 and 2 of the hollow body at point 5 take place in one operation, the inserted Polyethylene film 4 prevents the inner sides of the strip 3 from being welded together. Once this has been carried out, the final edge connection 6 of the hollow body can open any type by gluing, sewing, sealing or welding.

In the edge connections shown in Fig. 2 and 3, the internal pressure comes has no effect at all on the peripheral locations connected at 6. By in less Removal of welded thermoplastic plastic strips from the edge connection 3 namely the edge connection 6 is relieved.

The internal pressure stresses this thermoplastic plastic strips 3 by a shear load that can be withstood much better than that on the edge connection 6 acting peel load. A similar effect also occurs the in F i g. 2 with 8 designated point. A comparison with FIG. 1 shows that also at this point by the measure according to the invention of the separation of the both hollow body halves is countered in an effective manner.

The use of a polyethylene film can be avoided if two strips of a thermoplastic plastic film are arranged, the each individually welded to the respective hollow body wall 1 or 2. That A construction example for this is shown in FIG. 1 i g. 4 to 6 shown. Before the two Hollow body walls 1 and 2 are placed on top of one another, is a thermoplastic on each Plastic strips 7 are welded on at point 9, whereby provision is also made that the hollow body walls 1 and 2 protrude accordingly. The above Hollow body walls 1 and 2, as shown in Figure 5, bent back, and it becomes the Welding the free edges of the thermoplastic plastic strips 7 to the Position 11 carried out. The hollow body walls 1 and 2 are then laid out flat again (Fig. 6), whereupon the edge connection 6 takes place again in any manner.

A saving in manipulation and in the number of required Weld seams can, however, according to a design variant, as in FIGS. 7 and 8 shown. There is also a thermoplastic plastic strip each 7 'welded to each of the two hollow body walls 1 and 2 at point 9, however the edges of the latter do not protrude, but the thermoplastic plastic strips 7 'and the hollow body walls 1 and 2 are flush with the edge. The two parts will now placed on top of each other, and the edge connection 6, which now includes all four layers, is welded.

An edge connection similar to the embodiment according to FIGS. 1 and 2, however without using a polyethylene film, can be obtained if in place of one Foil strip is a strip of fabric coated with thermoplastics is used. As shown in Fig. 9, the coated fabric strip 3 with the fabric sides folded towards each other and between the hollow body walls 1 and 2 so inserted that the latter still protrude a little. The Point 5 of the strips 3 are welded to the hollow body wall 1 or 2, the inner Prevent the fabric sides from welding the inside of the reinforcement strip. Since the edge connection 6 is preferably also made by welding, can by appropriate arrangement of the welding electrode welding to the Welds 5 and 6 take place at the same time.

In the embodiment according to FIG. 10, the edge of the hollow body is through a Y-shaped profile strip injection-molded from preferably soft polyvinyl chloride 10 reinforced. The profile strip 10 is in this case an edge fit with the one web inserted between the hollow body walls 1 and 2 and advantageously also in one Work step welded together at the seams 5 and 6. About welding To prevent the two forked webs in the middle, is on their inside in the area of the welds 5 at the Stellell one Insulating compound, z. B. an electrically conductive paint applied.

Using the construction according to the invention results an airtight edge section of hollow bodies through which there is a risk of tearing open the thermoplastic plastic coating on the fabric is reliably avoided.

The idea underlying the invention can also be used for training of the welds applied between the chambers of an inflatable hollow body in which, as shown in FIG. 2 shown, the hollow body walls 1 and 2 not directly with each other, but connected to each other by the interposition of a web 8 The flanges of the webs 8 are welded to the hollow body walls 1 and 2 will.

Claims (4)

Claims: 1. Edge connection for inflatable hollow bodies resilient and dense material, in which the edges of the hollow body through with the inside of the hollow body glued strips are additionally reinforced, thereby characterized in that on the inside of the made with weldable thermoplastic Plastic-coated fabrics existing hollow body walls (1, 2) one or two thermoplastic plastic strips (3, 7 and 7 ') at a short distance from the edge connection (6) of the Hollow body lying points (5 or 9) welded are. 2. Edge connection according to claim 1, using a bifurcated Reinforcement strip, characterized in that the fork ends of a Y-shaped Strip (10) on the hollow body walls (1, 2) at a short distance from the points (5) lying on the edge connection (6) of the hollow body are welded, while the one extending from the apex of the fork forms the stem of the fork Strip is welded into the edge connection (6) of the hollow body walls. 3. Edge connection according to claim 1, characterized in that the Strip (3) made of a strip of fabric coated with thermoplastics consists. 4. Edge connection according to Claims 1 and 2, characterized in that that the fork-shaped profile strip (10) on the inside of the two forked Bars with an insulating compound that prevents welding, e.g. B. one electric conductive lacquer layer (11) is provided. Documents considered: German Patent No. 845 678; German Auslegeschrift No. 1 082 686; French patent specification No. 963 865, 1169286; U.S. Patent Nos. 1,625,582, 1,939.