Inflatable fiber reinforced bag

Abstract

The present invention relates to an inflatable fiber-reinforced bag having a flat and generally circular shape in an uninflated state, the inflatable fiber-reinforced bag comprising at least one inner elastomeric layer, a fiber-reinforced structure, and an outer elastomeric layer, wherein a reinforcing structure consisting of continuously wound reinforcing fibers extending from one pole to another substantially encloses the poles.

Description

Technical Field

[0001] The invention relates to an inflatable fiber reinforced bag. Background Art

[0002] Inflatable fiber-reinforced bags can be realized as so-called air lift bags, which are primarily used in low insertion height situations where heavy objects need to be lifted, such as buildings, bridges, vehicle or structure rescue, load transfer, heavy truck or aircraft recovery and machinery moving.

[0003] Traditionally, lift bags have a rectangular, preferably square, geometry. They are manufactured by manually folding several layers of fabric reinforcement sheets of unvulcanized rubber into a square shape, which is then vulcanized by compressing the unvulcanized ("green") product in a press between two mold plates. No mandrel is used in the manufacturing process. When these square lift bags are inflated, their flattened square shape changes to a "pillow" shape.

[0004] In order to improve some of the inefficiencies found in such conventional square lifting bags, such as stress concentrations in the corner areas, a round lifting bag was developed as described in EP 0 626 338 A1. The round lifting bag of EP 0 626 338 A1 is designed as an isotensoid structure, which means that when the lifting bag is inflated in its free (unloaded) state, the tension of all the reinforcing ropes is the same. The isotensoid structure described in EP 0 622 338 A1 is obtained by winding the reinforcing ropes along a geodetic path on a predetermined shape, which is defined by the following formula:

[0005] where q is defined as

[0006] Y0 is the diameter of the polar opening, Y u is the minimum radius of the optimum part of the pressure vessel, Y i is the maximum radius of the optimal part of the pressure vessel, thereby forming a three-dimensional mandrel in the shape of a flat cylinder with continuously curved edges, an extruded sphere like the shape of Gouda cheese. To manufacture the inflatable bag, material layers such as elastomers and fiber reinforcements are arranged on the outside of the mandrel, the shape of which defines the shape of the body cavity of the body in question. After or during the molding process, in which, for example, a certain degree of curing of the material layers occurs, the mandrel is removed from the body.

[0007] It is noteworthy that patent publication EP 2 960 033 A2 describes the design and use of such a three-dimensional mandrel, which is assembled from a set of mutually bonded main parts, which can be released from each other and which can be disassembled through an opening.

[0008] The advantage of the lifting bag of EP 0 626 338 A1 compared to conventional square bags is that the isotensoid reinforcement structure provides a better force distribution along the reinforcement structure, resulting in a more efficient use of material and a better force-stroke (lift) curve.

[0009] In the manufacturing process described in EP 0 626 338 A1, the reinforcing rope applied by automatic fiber winding is wound on a three-dimensional mandrel having a shape defined by the above equation, while the manufacture of traditional square bags manufactured by manually folding fabric reinforced rubber sheets does not require a mandrel. In addition, in the method described in EP 0 626 338 A1, an elastomer layer is also applied on the three-dimensional mandrel, making the method more complicated. After or during the molding process, an opening for removing the three-dimensional mandrel from the main body is formed in the process of winding the reinforcing fibers to a certain distance from the pole, thereby also forming a polar opening in the reinforced structure of the hollow body. Therefore, the round lifting bag produced by the method of EP 0 626 338 A1 requires additional closing elements (such as metal flanges) to close these polar openings in the hollow fabric reinforced elastomer. However, the use of such a closing flange will increase the thickness and weight of the product, which is not ideal from the perspective of product performance.

[0010] Patent publication WO 2018 / 233803 Al describes a production method for manufacturing a circular lifting bag, which includes an inner elastomer layer, a fabric reinforcement layer, and an outer elastomer outer layer. According to WO 2018 / 233803 Al, the reinforcement layer includes a single or multiple prefabricated two-dimensional fiber reinforcement layer in the form of a tube or tubular structure, which is pulled through the entire arrangement of the core like a "stocking". According to the description, the reinforcement "stocking" can be pulled through the entire core and can also cover the poles, so that there are no polar openings. Although the method described in WO 2018 / 233803 A1 does not require winding continuous fibers in a certain winding geometry (including the necessary equipment design) as required by EP 0 622 338 A1, and polar areas may also be covered, the resulting reinforcement structure does not have the efficiency of the reinforcement structure obtained by the reinforcement rope along a geodesic path from one pole to another in the method of EP 0 622 338A1. Summary of the invention

[0011] The object of the present invention is to provide an improved inflatable fiber reinforced bag having the advantages of the effective reinforcement structure described in EP 0 622 338 A1 and having the further advantage of having a substantially closed polar opening, so that no additional closing element is required.

[0012] The object of the present invention is to provide an improved inflatable fiber reinforced bag. In particular, the object of the present invention is to provide a bag having a lower insertion height. Thus, according to one aspect of the invention, the fiber reinforced structure formed by continuously winding fibers between two opposite poles of the bag substantially closes the two poles. Since there are no substantial polar openings in the fiber reinforced rubber structure, a metal closing flange is no longer required. In the absence of a metal closing flange, the insertion height of the bag is much lower and the overall weight is also lower, thereby improving the performance of the bag. If the mandrel is left in the bag, its material and structure will not create an obstruction during the operational use of the bag.

[0013] Further advantageous embodiments according to the invention are described in the following claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will now be further explained based on a number of exemplary embodiments and the accompanying drawings. In the drawings: Figure 1A A schematic perspective view of a fiber-reinforced inflatable bag according to the present invention in a deflated state showing an exemplary embodiment; Figure 1B Shows Figure 1A The bag in the air-filled state; Figure 2A shows a schematic top view of a fiber reinforced structure according to the present invention, showing fibers extending from one pole to another substantially enclosing said poles; Figure 2B shows a schematic top view of another reinforcement structure according to the present invention, showing fibers extending from one pole to another leaving a polar opening; Figure 3A Shows Figure 1A A schematic cross-sectional view of a fiber-reinforced inflatable bag is shown; Figure 3B shows a schematic cross-sectional view of a fiber-reinforced inflatable bag having two fiber layers; Figure 3C Shows Figure 1A A schematic cross-sectional view of a fiber-reinforced inflatable bag is shown, which fiber-reinforced inflatable bag comprises, in the peripheral region, prefabricated fiber-reinforced material elements extending toward two poles; Figure 4A is a graph illustrating the thickness buildup of a reinforcement structure of a single reinforcement layer having two substantially closed poles; Figure 4B is a graph illustrating the thickness accumulation of a reinforcement structure having three reinforcement layers, each layer being at a different distance from the pole of the inflatable bag; Figures 5A-5F Schematic diagram showing different configurations of the fiber reinforcement profile and the bag outer profile.

[0015] Figure 5A Schematic representation of a fiber-reinforced structure with rotationally symmetric geometry and of an outer bag contour with rotationally symmetric geometry is shown.

[0016] Figure 5B Schematic representation of a bag outer contour with a fiber-reinforced structure having a rotationally symmetrical geometry and with a non-rotationally symmetrical geometry having a radially extending portion providing a handle for handling the bag is shown.

[0017] Figure 5C Schematic representation of a fiber-reinforced structure with rotationally symmetric geometry and a bag outer contour with rectangular geometry is shown.

[0018] Figure 5D Schematic representations of a fiber-reinforced structure having a geometry comprising a combination of circular and rectilinear portions and a bag outer contour having a rotationally symmetrical geometry are shown.

[0019] Figure 5E Schematic diagrams of a fiber-reinforced structure having a hexagonal shape with rounded corners and a product outer contour having a hexagonal shape and having a non-rotationally symmetrical geometry are shown.

[0020] Fig. 5F Schematic diagrams showing a fiber reinforced structure having a geometry comprising a combination of circular and rectilinear portions and a product outer contour having a rectangular geometry.

[0021] It should be noted that the accompanying drawings only illustrate preferred embodiments according to the present invention. In the accompanying drawings, the same reference numerals represent the same or corresponding parts. DETAILED DESCRIPTION

[0022] Figure 1A A schematic perspective view of a fiber reinforced inflatable bag 1 according to the invention is shown in an exemplary embodiment. The bag 1 is provided with an input port 9 having a valve for respectively inflating and deflating the bag 1. Figure 1AIn the embodiment, the bag is in a deflated state. The bag 1 has a generally rotationally symmetrical geometry with respect to the rotational symmetry axis A and can be used as a so-called lifting bag for lifting heavy objects such as collapsed buildings, for example, in emergency situations. Generally, the lifting bag can be brought from a deflated state to an inflated state by pressurizing the bag 1. Similarly, the bag 1 can be brought from an inflated state to a deflated state by depressurizing. Generally, the bag can be stored and transported in a deflated state, while the bag can generate a lifting force when positioned and pressurized.

[0023] Figure 1B A schematic perspective view of the bag 1 in the inflated state is shown. Likewise, the bag 1 has a generally rotationally symmetric geometry with respect to an axis of rotational symmetry A.

[0024] Figure 2A A schematic top view of a fiber-reinforced structure according to the invention is shown. The fiber-reinforced structure comprises fibers 4 extending from one pole 5 to another pole 5, substantially enclosing said poles 5. The two poles 5 are opposite each other at an axis of rotational symmetry A. Figure 2B In FIG. 1 , a schematic top view of another fiber reinforced structure according to the invention is shown. Here, the fiber reinforced structure comprises fibers 4 extending from one pole to another pole, leaving polar openings 6.

[0025] Preferably, the fiber reinforced structure of the bag is wound with a single or multiple fibers between two relative poles of the bag. The single or multiple fibers can be wound along a geodesic path. Advantageously, multiple fibers can be wound continuously or simultaneously, for example using manually controlled or automatic filament winding equipment. The reinforcing fibers can be, for example, flat yarn bundles or have a rope structure. The reinforcing fibers can be rubberized and / or embedded in rubber strips to prepare a process for forming a reinforcement layer structure. It is worth noting that in addition to continuously winding the fibers, another winding method can also be used, for example, by using relatively short individual fibers or fiber strips embedded in rubber to intermittently wind the fiber reinforced structure, thereby producing multiple starting points and end points.

[0026] By eliminating the metal closing element, which is no longer necessary since the polar opening is essentially closed by the fiber-reinforced structure, an inflatable structure having a small height in the deflated state can be achieved.

[0027] Figure 3A A schematic cross-sectional view of a fiber-reinforced inflatable bag 1 is shown, wherein the fiber-reinforced structure substantially encloses the Figure 2A The poles shown. Figure 3AThe bag 1 in comprises a sandwich structure in which a first elastomeric layer 3 (also referred to as an elastomeric liner) is covered by a single fiber layer 4. Then, a second elastomeric layer 7 is applied on top of the single fiber layer 4 so that the fibers 4 are embedded in the elastomeric material to form a fiber reinforced layer structure 3, 4, 7. The fibers 4 are wound around the poles 5', 5'', essentially closing the poles 5', 5''. Optionally, an additional reinforcing element 8 is applied underneath or on top of the fiber layer 4 to provide additional reinforcement to the poles 5', 5'' and the polar regions. The additional reinforcing element 8 can be realized as a textile reinforcement and / or can include a thin plate, such as a 1-2 mm thick metal plate. The fiber reinforced structure 3, 4, 7 surrounds the compartment 2, which can be inflated and deflated separately via the input port 9 shown in Figure 1. In Figure 3A In the figure, the bag is shown in a deflated state, wherein there is no or substantially no air or other gas in the compartment 2. The compartment 2 is surrounded by an airtight elastomeric liner 3.

[0028] Figure 3B A schematic cross-sectional view of a fiber reinforced inflatable bag 1 is shown. The fiber reinforced structure includes two layers of reinforcing fibers, a first inner layer 4a having a substantially closed pole, and a second layer 4b leaving a polar opening. Here, there are multiple fiber layers 4a, 4b, so that the bottom layer 4a is closer to the pole 5 than the top layer 4b covering the bottom layer 4a. Similarly, the fiber layers 4a, 4b are sandwiched between the elastomer liner 3 and the elastomer cover 7 to form a fiber reinforced layer structure 3, 4, 7. Optionally, an elastomer layer can be added between the fiber layers 4a and 4b. The fiber bottom layer 4a is wound around the poles 5', 5'', substantially closing the poles 5', 5''. In addition, the fiber top layer 4b is wound to the offset distance Db of the bag pole 5. At the offset distance Db, the fiber top layer 4b surrounds the polar opening 6 at each pole 5', 5''. The reinforcing ropes can be distributed on different polar openings in an integral manner, wherein the reinforcing ropes are wound at different polar openings in an alternating order. Alternatively, reinforcing rope can be distributed on different polar openings in a progressive manner, and reinforcing rope is wound with increasingly larger polar opening in each subsequent ring or a plurality of subsequent rings thus. Reinforcement layer can have different polar openings on the both sides of bag.Optionally, in polarity region, below or on the top of fiber layer 4a, 4b, one or more additional reinforcing elements 8 are applied.By applying a plurality of fiber layers 4, polar opening can be progressively increased.For example, two-layer, three-layer, four-layer or even more layers of fiber layers can be applied.Yet, the polar opening can use above-mentioned other reinforcing element to carry out additional enhancing, so that the overall thickness of reinforcing layer structure is relatively small.

[0029] Figure 3C A schematic cross-sectional view of a fiber-reinforced inflatable bag 1 is shown, wherein the fiber-reinforced structure substantially encloses the Figure 3AOptionally, additional reinforcing elements 6 can be applied in the peripheral region below or on top of the fiber layer 4 to provide additional reinforcement to the peripheral region. The additional reinforcing elements 6 can be implemented as (prefabricated) textile reinforcements. Typically, Figure 3A , 3B The bag shown in 3C comprises an inflatable reinforced elastomer formed from a fiber reinforced layer structure 3,4,7.

[0030] Figure 4A is a diagram illustrating the thickness accumulation of a reinforcement structure of a single reinforcement layer 4 having two substantially closed poles 5. Here, the thickness h is described as a function of the distance z from the axis of rotational symmetry A. Starting from zero distance z, the diagram has a maximum thickness H1 at a distance z1. As the distance z increases, the thickness of the layer decreases until a minimum thickness of the layer is reached. As a result, the maximum thickness accumulation of the reinforcement structure has a value H1.

[0031] Figure 4B is a diagram illustrating the thickness accumulation of a reinforced structure with three reinforcement layers, with fiber layers 4a, 4b, 4c surrounding a respective pole 5, wherein the first bottom layer 4a forms a substantially closed pole, while the second layer 4b and the third layer 4c leave a polar opening 6 with a respective diameter. Preferably, the size of the respective polar opening 6 (in other words, the distance from the pole 5 to the fibers in the respective layer 4b, 4c) increases stepwise with each subsequent reinforcement layer. In the diagram shown, a first local maximum thickness HH1 is reached at a first distance z1 due to the first bottom fiber layer 4a, a second local maximum thickness HH2 is reached at a first distance z2 due to the second fiber layer 4b covering the first fiber layer 4a, and a third local maximum thickness HH3 is reached at a first distance z3 due to the third fiber layer 4c covering the second fiber layer 4b. The third local maximum thickness HH3 is also a global maximum thickness, which is less than Figure 4A The maximum thickness H1 produced by a single reinforcement layer 4 is shown, thereby demonstrating that the total stack thickness can be reduced by dividing the reinforcement structure into a plurality of fiber layers distributed radially outwards.

[0032] By distributing the cumulative thickness of the fibers in the polar regions, a flatter surface may be formed in the polar regions when the bag is inflated. Adding additional reinforcement elements 8 of a rigid material (e.g., a thin metal sheet) on top of or below the fiber reinforcement layer 4 in the polar regions will further enhance the flatter surface in the polar regions when the bag is inflated. Having a flatter surface in the polar regions may be beneficial in providing a more stable lifting surface.

[0033] It is worth noting that, in principle, the fiber-reinforced structure has a generally rotationally symmetrical geometry relative to the rotational symmetry axis A, but may also have another shape profile. In addition, the outer contour of the bag may have a rotationally symmetrical geometry, but may also have another shape profile. For example, the outer contour of the bag may be rectangular, elliptical or polygonal, or circular, with one or more radially extending parts (e.g., handles) in the peripheral area.

[0034] Figures 5A-5F Different embodiments of the geometry of the reinforcement structure and bag profile are shown. It should be understood that the possibilities are not limited to Figures 5A-5F Many variations are possible without limitation to the embodiments shown.

[0035] Figure 5A A schematic diagram of a fiber reinforced structure with rotationally symmetrical geometry 10a and a product outer contour with rotationally symmetrical geometry 11a is shown. In the peripheral area of ​​the bag where the valve 9 is located, additional material may be added around the valve providing radial extensions supporting the valve.

[0036] Figure 5B Schematic representations of a fiber reinforced structure with a rotationally symmetrical geometry 10a and a product outer contour with a rotationally asymmetrical geometry having a radially extending portion 11b providing a handle for handling the bag are shown.

[0037] Figure 5C A schematic diagram of a fiber-reinforced structure with a rotationally symmetrical geometry 10a and a product outer contour with a rectangular geometry 11c is shown.

[0038] Figure 5D A schematic representation of a fiber-reinforced structure having a geometry that is not rotationally symmetrical and comprises a contour shape 10 b consisting of circular and rectilinear portions and a bag 11 a having a rotationally symmetrical outer contour is shown.

[0039] In another embodiment, both the contour of the reinforcing structure and the outer contour of the bag may have a non-rotationally symmetrical geometry.

[0040] Figure 5E Schematic representations of a fiber-reinforced structure with a rotationally non-symmetrical geometry in the form of hexagons 10 c with rounded corners and a bag outer contour with a rotationally non-symmetrical geometry in the form of hexagons 11 d are shown.

[0041] Fig. 5F Schematic diagrams of a fiber-reinforced structure having a geometry that is not rotationally symmetrical and includes a contour shape 10 b consisting of circular portions and rectilinear portions and a product outer contour having a rectangular geometry 11 c are shown.

[0042] The present invention is not limited to the embodiments described above. It will be appreciated that many variations are possible.

[0043] These and other embodiments will be apparent to those skilled in the art and are considered to fall within the scope of the invention as defined in the appended claims. For the sake of clarity and brevity, each feature is described herein as a part of the same embodiment or different embodiments. However, it should be understood that the scope of the invention may include embodiments having all or some combinations of the described features.

Claims

1. An inflatable fiber reinforced bag having a flat and generally circular shape in an uninflated state, the inflatable fiber reinforced bag comprising at least one inner elastomer layer, a fiber reinforced structure covering the at least one inner elastomer layer, the fiber reinforced structure being formed by continuously winding fibers between opposite poles of the bag, the fibers substantially enclosing the two poles, the bag also comprising an outer elastomer layer covering the fiber reinforced structure, and an inflation valve unit penetrating the at least one inner elastomer layer, the fiber reinforced structure and the outer elastomer layer.

2. The inflatable fiber reinforced bag according to claim 1, wherein: The fiber reinforced structure comprises a plurality of fiber layers, forming a layer pack.

3. The inflatable fiber reinforced bag according to claim 2, wherein: The fiber reinforcement layers closer to the inside of the bag are wound closer to the pole than the fiber reinforcement layers further from the inside of the bag.

4. The inflatable fiber reinforced bag according to claim 3, wherein: The fiber reinforcement layer closest to the inside of the bag is wound closest to the pole, while the fiber reinforcement layer further away from the inside of the bag is further away from the pole than its previous layer.

5. An inflatable fiber reinforced bag according to any one of the preceding claims 2 to 4, wherein: The fiber reinforced structure comprises a plurality of fiber layers and further comprises an intermediate elastomeric layer sandwiched between subsequent fiber layers of the fiber reinforced structure.

6. An inflatable fiber reinforced bag according to any one of the preceding claims, further comprising further reinforcing elements proximate to at least one pole.

7. An inflatable fiber reinforced bag according to any one of the preceding claims, further comprising prefabricated fiber reinforcement elements extending in the peripheral region towards two poles.

8. An inflatable fiber reinforced bag according to any one of the preceding claims, wherein: The inner elastomeric layer and / or the middle elastomeric layer and / or the outer elastomeric layer have been vulcanized onto the fiber reinforced structure.

9. An inflatable fiber reinforced bag according to any one of the preceding claims, wherein: The fiber-reinforced structure has a rotationally symmetrical geometry, and the outer shape of the bag has a rotationally asymmetrical geometry.

10. An inflatable fiber reinforced bag according to any one of the preceding claims, wherein: The bag has a generally rotationally symmetrical shape, wherein the bag is provided with single or multiple radial extensions in the peripheral region providing additional features such as handles for manipulating the bag.

11. An inflatable fiber reinforced bag according to any of the preceding claims, having a fiber reinforced structure having a non-rotationally symmetrical shape, such as a closed profile with circular parts and substantially straight parts interconnecting subsequent circular parts, or a polygonal profile.

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