METHOD FOR MANUFACTURING AN INFLATABLE LIFTING CUSHION AND LIFTING CUSHION

Abstract

A method for producing an inflatable lifting cushion includes providing a core with main surfaces in the form of a front side and a rear side and an outer peripheral region. A two-dimensional layer of vulcanizable material is applied on the front side and rear side of the core. A single-layer or multi-layer prefabricated two-dimensional fiber-reinforcing layer is drawn in the form of a tube, onto the arrangement including the core and two-dimensional layers of vulcanizable material located on the core so that the fiber-reinforcing layer, extending around the peripheral region, covers the two-dimensional layers of vulcanizable material at least partially. A further two-dimensional layer of vulcanizable material is applied to the fiber-reinforcing layer at the front side and the rear side of the core. The arrangement is heated to obtain a bond of the fibers of the fiber-reinforcing layer with the two-dimensional layers of the vulcanizable material.

Claims

1. A method for producing an inflatable lifting cushion comprising: providing a core with main surfaces comprising a front side and a rear side and an outer peripheral region, applying a two-dimensional layer of vulcanizable material on the front side and the rear side of the core, pulling a single-layer or multilayer prefabricated two-dimensional fiber-reinforcing layer onto the arrangement comprising the core and two-dimensional layers of vulcanizable material located thereon so that the fiber-reinforcing layer, extending around the peripheral region, covers the two-dimensional layers of vulcanizable material at least partially, applying a further two-dimensional layer of vulcanizable material to the fiber-reinforcing layer in the region of the front side and the rear side of the core; and heating the arrangement so that a bonding of the fibers of the fiber-reinforcing layer with the two-dimensional layers of vulcanizable material is obtained, wherein as a single-layer or multi-layer prefabricated two-dimensional fiber-reinforcing layer, a tubular structure is pulled over the arrangement of the core and the two-dimensional layers of vulcanizable material located thereon like a stocking.

2. The method of claim 1, wherein a continuous tube is used as a single-layer or multi-layer prefabricated fiber-reinforcing layer, and after cutting off of a necessary length, open tubular ends of the fiber-reinforcing layer are respectively beaten inward onto the front side and back side of the core.

3. The method according to claim 1, wherein the tubular structure or the continuous tube is stretchable in diameter.

4. The method according to claim 1, wherein the pre-fabricated fiber-reinforcing layer is a fabric or a knitted fabric.

5. The method according to claim 1, wherein the two-dimensional layer of vulcanizable material is free of fiber reinforcement.

6. The method according to claim 1, wherein the two-dimensional layer of vulcanizable material has an at least substantially round shape.

7. The method according to claim 1, wherein the two-dimensional layer of vulcanizable material has an at least substantially rectangular shape.

8. The method according to claim 1, wherein the two-dimensional layers touch in the outer peripheral region or at least can be brought into contact.

9. The method according to claim 1, wherein an additional strip of vulcanizable material is provided in the outer peripheral region of the two-dimensional layers running along a circumference around the peripheral region.

10. The method according to claim 1, wherein viewed in cross-section, the core also has a lenticular shape, a cushion shape, a round shape, an ellipsoid shape, a rectangular shape or a combination thereof.

11. The method according to claim 1, wherein the core consists of a material which is removable after heating.

12. The method according to claim 1, wherein the core consists of a material which contains chalk.

13. The method according to claim 1, wherein the core is flushed out after heating.

14. The method according to claim 1, wherein prior to application of the two-dimensional layers a pole cap is placed on the front side and/or the rear side of the core.

15. The method according to claim 14, wherein the fiber-reinforcing layer has an annular end portion which extends toward or is received by the pole caps.

16. An inflatable lifting cushion with main surfaces comprising a front side, a rear side and a peripheral region, wherein a distance of the front side to the rear side increases when the lifting cushion is inflated, the cushion comprising: a two-dimensional layer of vulcanizable material on the front side, a two-dimensional layer of vulcanizable material on the rear side, a fiber-reinforcement of the vulcanizable material, a single-layer or multi-layer two-dimensional fiber-reinforcing layer provided as a fiber reinforcement, said layer extending around an entire circumference of the peripheral region continuously without a separation point and covering the two-dimensional layers of vulcanizable material at least partially, and fibers of the two-dimensional layer end in the region of the front side and/or the rear side.

17. The inflatable lifting cushion according to claim 16, wherein the fibers of the two-dimensional fiber-reinforcing layer extend into the front side and/or the back side around the peripheral region.

18. The inflatable lifting cushion according to claim 16, wherein the fiber-reinforcing layer forms overlap areas on the front side and/or the back side.

19. The inflatable lifting cushion according to claim 16, comprising at least one further two-dimensional layer of vulcanizable material on an outside of the fiber-reinforcing layer.

20. The inflatable lifting cushion according to claim 16, wherein the two-dimensional layers of vulcanizable material are round or rectangular.

21. The inflatable lifting cushion according to claim 16, wherein on the front side and/or the rear side, a pole cap is provided and the fiber-reinforcing layer comprises an annular end portion which extends to the pole cap or is received by the pole cap.

22. The inflatable lifting cushion according to claim 21, wherein the pole cap comprises a receptacle or step which receives respective end portions of the two-dimensional layers and/or of the fiber-reinforcing layer.

Description

DESCRIPTION OF THE INVENTION ON THE BASIS OF EXEMPLARY EMBODIMENTS

[0030] Advantageous embodiments of the method and lifting cushion according to the invention are explained below with reference to the drawing figures. The figures show the following:

[0031] FIG. 1 a highly simplified schematic representation of an arrangement with a lifting cushion for lifting heavy loads;

[0032] FIG. 2 different stages of a first embodiment of the method according to the invention for producing a lifting cushion;

[0033] FIG. 3 a partial sectional view of a lifting cushion according to another embodiment of the present invention;

[0034] FIG. 4 different stages of a second embodiment of the method according to the invention for producing a lifting cushion;

[0035] FIG. 5 a highly simplified schematic representation of the arrangement of a plurality of interconnected lifting cushions; and

[0036] FIG. 6 an enlarged sectional view of the area of a pole cap of a lifting cushion according to the invention.

[0037] Reference numeral 1 in FIG. 1 denotes a lifting cushion for lifting heavy loads. The lifting cushion has a flattened shape in the unpressurized state. This shape makes it possible for the lifting cushion to be inserted into narrow gaps during use. Such lifting cushions are intended for a wide variety of applications. For example, lifting cushions can be used to lift vehicles or aircraft in accidents, to raise collapsed walls or ceilings during earthquakes. In addition, lifting cushions can also be used as assembly aids or maintenance/repair aids in a wide variety of areas. The lifting cushion 1 is here used with its top 1a and bottom 1b placed in a gap between the base and the load to be lifted. The loading direction therefore essentially corresponds to the orientation of the arrow shown in FIG. 1.

[0038] The filling of the lifting cushion 1 is usually carried out with compressed air, which is generated via a compressed air source 2, for example a compressed air cylinder, and is supplied via a hose 4 to the lifting cushion 1. Between the lifting cushion 1 and the compressed air source 2 is a control valve 3, by means of which the operator can control the lifting of the lifting cushion. In the inflated, unloaded state, the lifting cushion has approximately the shape shown by the dotted outline.

[0039] The manufacture of the inventive, for example lenticular lifting cushion 1, will be described in more detail below. First, a core 5 is provided, which when viewed in cross-section, has approximately a lenticular basic shape, for example. The core 5 comprises a front side 5a, a back side 5b and a circumferential peripheral region 5c which approximately correspond in orientation to the front side 1a, the bottom side 1b and the peripheral region 1c of the lifting cushion 1 from FIG. 1.

[0040] The core 5 consists of a solid material, such as chalk, which can be removed from the lifting cushion 1 after the production thereof. After provision of the core 5, as shown in FIG. 2b, a respective two-dimensional layer 6a and 6b of a vulcanizable material or an elastomer is disposed both on the front side 5a and on the back side 5b and held in position. The layers 6a, 6b touch each other in the outer peripheral region 5c of the core 5. Preferably, the layers 6a, 6b are rubber discs, in particular discs which have no fabric reinforcement. The positioning of the two two-dimensional layers 6a, 6b can be accomplished by suitable devices. Furthermore, in the context of this process step, a valve can be used 11, which serves to establish a connection with a hose line of a compressed air source in order to fill the lifting cushion. Accordingly, the valve 11 or a corresponding valve insert is positioned in an opening of the layer 6a, for example.

[0041] According to FIG. 2c, the arrangement of FIG. 2b is subsequently covered with a single-layer or multi-layer, prefabricated two-dimensional fiber-reinforcing layer 7, preferably in the form of a fiber-reinforcing tube, in such a way that the arrangement consisting of core 5 and layers 6a, 6b is positioned essentially transverse relative to the longitudinal orientation of the tube and extends lateral to the arrangement at approximately equal lengths.

[0042] Subsequently, the free ends of the fiber-reinforcing tube must be pushed inwards and form joints 10a, 10b approximately in the central region of the front and back sides 5a, 5b of the core 5 joints. The fiber-reinforcing tube may alternatively have a flexibility that causes the protruding areas to more or less automatically sit against the front or back side of the arrangement or at least against a part thereof. In any case, the arrangement according to FIG. 2c forms a fiber reinforcement with fibers which extend from one end of the tube over the respective peripheral region of the arrangement to the other end of the tube, and indeed fully-circumferential to the core 5.

[0043] After the ends of the fiber-reinforcing tube are pushed in, the fibers end at these joints 10a, 10b as shown in FIG. 2d, so that either overlapping regions 12a, 12b of the fiber-reinforcing can be provided or else the fibers can also abut each other or can lie radially relative to each other depending on the starting material of the fiber reinforcement 7.

[0044] Thereafter, according to FIG. 2e, a further layer 6c, 6d of vulcanizable material or elastomer is applied both on the front side and on the back side. Consequently, the arrangement shown in FIG. 2e forms a sandwich-like layer sequence of core 5, two-dimensional layer 6a, fiber-reinforcing layer 7, two-dimensional layer 6c on the side shown on the left in FIG. 2e. The two-dimensional layer 6c also has an opening (not shown in FIG. 2e) for the valve 11.

[0045] The arrangement is now subjected to a hot vulcanization step in which the vulcanizable material of the layers 6a, 6b, 6c, 6d is liquefied and forms an intimate elastomer/fiber matrix with the fibers of the fiber-reinforcing layer 7. The layers 6a, 6b, 6c, 6d thus lose their interfaces and form a uniform layer of elastomer in which the fibers are embedded.

[0046] After cooling the assembly, the hose 4 is connected via the valve 11 and the core 5 is flushed out by means of water, for example. The core 5 dissolves gradually, as indicated in FIG. 2g. The finished lifting cushion is shown in FIG. 2h. It has a flattened shape and is characterized by optimal mechanical stress characteristics.

[0047] According to an alternative embodiment of the present invention shown in FIG. 3, an additional strip 8 of elastomeric material or elastomer can be laid around or provided in the peripheral region 1a of the lifting cushion 1, the fiber-reinforcing layer 7 being located on the outside of said material or elastomer prior to vulcanization.

[0048] The present invention is particularly suitable for the production of lifting cushions with so-called pole caps. In applications involving bridging larger distances, such lifting cushions can be connected at the respective pole caps and thereby be stacked and pumped individually in the stack. Adjacent stacked lifting cushions are locked to each other via their pole caps. The pole caps have a locking mechanism for this purpose. The pole caps are used for positioning and mechanical fixation of the lifting cushions to each other, so that a reproducible lifting operation can also be carried out using stacked lifting cushions.

[0049] For this purpose, after provision of the core 5, pole caps 13a and 13b, for example made of steel, are positioned preferably on both sides, on the front 5a and rear side 5b of the core 5, and then the two two-dimensional layers 6a, 6b are placed or applied as shown in FIG. 4a. For this purpose, the two-dimensional layers 6a, 6b must have a recess corresponding to the pole cap.

[0050] Subsequently, according to the invention, the two-dimensional fiber-reinforcing layer 7, as in the case of the method described under FIG. 2c, is applied to the arrangement. The fiber-reinforcing layer 7 here already has the required length or is then cut to length accordingly. The open end regions are then pulled inwardly so that the end regions of the fiber-reinforcing layer 7 extend up to the respective pole cap 13a, 13b, as shown in FIG. 4c.

[0051] Subsequently, according to FIG. 4d, a further two-dimensional layer 6c and 6d is applied to the front and rear side 5a and 5b of the core 5 and the overall arrangement, as shown in FIG. 4d, is subjected to a vulcanization process. After vulcanization, the core is removed in the manner already described in FIG. 2g. For the sake of simplicity, therefore, reference will be made to this.

[0052] As a final result, a lifting cushion as shown in FIG. 4e is provided, which ensures the possibility of stacking, as shown in a greatly simplified representation in FIG. 5.

[0053] The pole cap 13a, 13b can, as shown enlarged in the arrangement of FIG. 6, preferably have a receptacle 14 or step into which the two-dimensional layers 6a, 6c and the annular end region 7a of the fiber-reinforcing layer 7 are accommodated.

[0054] The tubular fiber-reinforcing layer 7 may in particular be one that is stretchable in diameter. The fiber-reinforcing layer 7 may be one or more layers.

[0055] Furthermore, the prefabricated fiber-reinforcing layer 7 may be a woven fabric or a knitted fabric.

[0056] The lifting cushion can have a round or rectangular shape.

LIST OF REFERENCE SIGNS

[0057] 1 lifting cushion [0058] 1a top side [0059] 1b bottom side [0060] 1c peripheral region [0061] 2 compressed air source [0062] 3 control valve [0063] 4 hose line [0064] 5 core [0065] 5a front side [0066] 5b back side [0067] 5c peripheral region [0068] 6a two-dimensional layer [0069] 6b two-dimensional layer [0070] 6c two-dimensional layer [0071] 6d two-dimensional layer [0072] 7 fiber reinforcement [0073] 7a annular end region [0074] 8 strips [0075] 9 fiber [0076] 10a joint [0077] 10b joint [0078] 11 valve [0079] 12a overlap area [0080] 12b overlap area [0081] 13a pole cap [0082] 13b pole cap [0083] 14 receptacle