Inner bag-free seamless air cushion and its production method

Abstract

The invention relates to an inner bag-free air cushion comprising a first fabric (10) made of polymeric material with a laminated nonwoven inner layer (11) and a woven fabric outer layer (12). The air cushion comprises a second fabric (50) made of polymeric material with a nonwoven inner layer (51), which is environmentally sealed to the first fabric by a thermal weld seam forming an inflatable air pocket (30).

Description

[0001] INNER BAG-FREE SEAMLESS AIR CUSHION AND ITS PRODUCTION METHOD

[0002] TECHNICAL FIELD

[0003] The present invention relates to an air cushion without an inner bag that restricts the movement of loads within a container during transport.

[0004] STATE OF THE ART

[0005] Two types of air cushions (dunnage) are used in load transportation: air cushions with inner bags and air cushions without inner bags. Air cushions with inner bags are generally used to provide extra protection during the transport of sensitive loads. These air cushions are wherein a multi-layer design and contain separate inflatable bags within. These bags form the overall structure of the cushion and absorb energy in the event of impact or shock. The inner bags limit the movement of the load and prevent potential damage.

[0006] Air cushions with inner bags are typically preferred when transporting sensitive materials or heavy loads. These cushions can be customized to fit the shape and size of a specific load and can be inflated and deflated quickly and efficiently. The inner bags are often interconnected to limit the movements that may occur during transport. These air cushions are typically made from durable and recyclable materials, thereby reducing environmental impact.

[0007] On the other hand, air cushions without inner bags are used to protect cargo and other sensitive items. This technology aims to reduce the effects of impacts and vibrations by regulating the air pressure within the cushion. The design of these cushions allows for more effective energy absorption during impact by utilizing an inner bag-free design. Air cushions without inner bags are generally used by being compressed into cargo areas or placed in specific regions, preventing the cargo from moving and potential damage during transport. These cushions are usually made from durable and recyclable materials, minimizing their environmental impact.

[0008] The inner bag-free air cushion technology also provides an additional level of protection to prevent potential damage from impacts and vibrations during the transportation of especially sensitive or fragile products. The design of these cushions is optimized to distribute the air inside quickly and effectively, preventing damage by dispersing the energy of an impact when the object strikes the cushion. These cushions are typically lightweight, easy to use, and can be folded flat to save space during storage and transport. However, they are not suitable for use with heavy loads.

[0009] SUMMARY OF THE INVENTION

[0010] The object of the invention is to provide an inner bag-free air cushion suitable for use in the transfer of heavy loads.

[0011] In order to achieve the above object, the invention relates to an inner bag-free air cushion comprising a first fabric made of polymeric material with a laminated nonwoven inner layer and a woven fabric outer layer. The air cushion includes a second fabric made of polymeric material with a nonwoven inner layer, which is environmentally sealed to the first fabric by a thermal welding seam forming an inflatable air pocket. The welding seam forms the air pocket without the need for additional stitching, and the woven fabric of the outer layer provides resistance to sudden heavy loads and cutting impacts, preventing the air pocket from bursting. This type of air cushion meets level 1 standards without an inner bag and can provide resistance up to level 5 with appropriate thickness. In a possible construction, the first and second fabrics can be laminated with nonwoven walls on both sides. In this case, for example, a nonwoven outer layer may also be present on the outside of the outer layer.

[0012] In a preferred embodiment of the invention, a valve is hermetically fixed to the inner layer by thermal welding and transfers compressed air from the outside environment into the air pocket at a pressure of 3-10 psi.

[0013] In a preferred embodiment of the invention, the second fabric includes a fabric outer layer laminated to the inner layer. In this structure, the air cushion increases impact resistance from both outer layers. Alternatively, a nonwoven outer layer may also be laminated to the outer side of the second fabric.

[0014] In a preferred embodiment of the invention, the outer layers are selected from the group consisting of polypropylene tarpaulin, polyethylene, and HDPE materials or combinations thereof. These materials provide high impact resistance when woven. Additionally, the inner layer can be simply obtained by laminating with an airtight film.

[0015] In a preferred embodiment of the invention, the inner layers consist of thermoplastic film. In this way, for example, it is possible to hermetically join the inner layers facing each other along a welding line by continuous heating, ultrasonic, laser, or another heat-based welding method. In an alternative embodiment, the weld stitch consists of multiple parallel stitches.

[0016] In a preferred embodiment of the invention, the weight of the first and second fabrics is adjusted between 60 gr / cm2and 240 gr / cm2, preferably between 60-100 gr / cm2. At this weight, it has been observed that an inner bag-free air cushion can be obtained with resistance levels ranging from level 1 to 5 as determined by KAR Institute standards.

[0017] In a preferred embodiment of the invention, the lamination thickness of the inner layer is adjusted between 20 microns and 120 microns, preferably between 30 and 70 microns. This thickness is sufficient to achieve a stitch thickness that can maintain hermeticity against impacts absorbed in the air pocket when the air pocket is formed by a weld stitch. Surprisingly, it has been found that this resistance shows similar performance to air cushions with inner bags.

[0018] In a preferred embodiment of the invention, the outer layer is made of seamless hose weaving. In this way, it is possible to form the cushion without any stitching. Simply, one edge of the first fabric is folded over itself to form the second fabric, and the air pocket is formed by thermal welding while simultaneously joining the first and second fabrics. Preferably, the first and second fabrics are a single-piece laminated fabric folded in half. This situation eliminates many stitching steps necessary to form the air cushion.

[0019] A preferred application of the invention comprises providing the first fabric with a nonwoven inner layer laminated onto a woven outer layer, aligning a second fabric of the same structure with the nonwoven inner layer of the first fabric, forming an airtight weld stitch surrounding an air pocket on corresponding faces of the inner layers using a welding apparatus. The first and second fabrics can be aligned on top of each other as separate pieces or obtained from a single piece of laminated fabric folded in half. Thus, an air cushion is provided without an inner bag.

[0020] In a preferred application of the invention, the welding apparatus completely merge the first and second fabrics along the weld stitch. In this way, the air pocket is formed by the weld stitch, and the cushion shape is obtained without the need for a separate joining stitch step.

[0021] A preferred application of the invention comprises mounting a valve passing through the outer layer from a mounting patch on the inner layer before the weld stitch. Mounting to the inner wall can be done simply with a weld stitch or with an additional step such as taping or gluing.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a top view representation of an inner bag-free air cushion according to the invention.

[0024] Figure 2 is a cross-sectional view of a representative application where the first and second fabrics are laminated on one side.

[0025] Figure 3 is a schematic representation of the production method of the air cushion according to the invention.

[0026] DETAILED DESCRIPTION OF THE INVENTION

[0027] In this detailed description, the invention is described without any limitation and only with reference to examples to better explain the subject matter.

[0028] In Figure 1 , the inner bag-free air cushion subject of the invention is schematically shown from the front. A first fabric (10) in rectangular form weighs 60 gr / cm2and is obtained by lamination. The first fabric (10) is obtained by weaving a polypropylene (PP) material yarn using a hose weaving method for the outer layer (12). The inner wall (11 ) is a nylon film. The first fabric (10) has equal dimensions for the inner layer (11) and the outer layer (12). A valve (40) extends outward from the front face (17) of the outer layer (12) of the first fabric (10). A rectangular weld stitch (20) surrounds the valve (40) at equal distances from the adjacent side edge (14) and perpendicular top edge (15) of the first fabric (10).

[0029] In Figure 2, a second fabric (50) obtained by folding one side edge (14) of the first fabric (10) is shown in cross-section. When the first fabric (10) is folded, the inner layer (11 ) made of nylon film becomes superimposed with the inner layer (51) of the second fabric (50). In this way, the first and second fabrics (10, 50) with outer layers (12, 52) on their outer-facing sides and inner layers (11 , 51 ) on their inner-facing sides are joined by a weld stitch (20). The weld stitch (20) provides fusion, causing the melting nylon films to stick together. Thus, an air pocket (30) surrounded by the weld stitch (20) is formed between the first and second fabrics (10, 50). The lower end of the valve (40) reaches the flat inner wall (32) of the air pocket (30) and extends cylindrically outward from the outer layer (12). In this way, pressurized air from the outside environment can reach the air pocket (30) by attaching to an inlet (41) of the valve (40) and accessing through its cylindrical nozzle (42).

[0030] A safety zone (Z) that makes it difficult to access the weld stitch (20) is provided between the outer part of the weld stitch (20) and the side edge (14) and top edge (15). The weld stitch (20) is adjusted to remain offset inward, not directly made at the side and top edges (14, 15), thus providing a safety zone (Z). In this way, any cutting or piercing extension is prevented from damaging the weld stitch (20).

[0031] In Figure 3, a schematic representation of a production method of the inner bag-free air cushion is shown. Here, the first fabric (10) and the second fabric (50) are supplied from separate lines. A laminated nonwoven inner layer (11) is poured over the woven outer layer (12) made of polypropylene yarn as hot raw material, cooled, and the laminated first fabric (10) is obtained. Similarly, the second fabric (50) is obtained by lamination. The first fabric

[0032] (10) is fed from a first roll (1) with the inner layer (11 ) facing downwards and the second fabric (50) is fed from a second roll (2) with the inner layer (51 ) facing upwards into the line. Thus, the first and second fabrics (10, 50) positioned on top of each other are transversely cut to the desired cushion length by a guillotine structure knife apparatus along the side edge (15) width. The cut first fabric (10) and second fabric (50) are fed to the welding apparatus (4). Here, the first and second fabrics (10, 50) form a fusion by melting with heat to form a weld stitch (20). Then, the operator attaches a compressor (not shown) to the nozzle (42) sewn from the inner wall (32) of the air pocket (30), inflates the air pocket (30) with a pressure of 3 psi, and closes the inlet (41). When a severe force is applied to the inner bag-free air cushion at the place where it is placed, the outer layer (12) of the first fabric (10) absorbs the tension with its woven structure. In this way, resistance is provided against pressure from a particularly sharp-edged element generating high pressure, and damage to the inner layer

[0033] (11) is prevented. The inner wall (11 ) ensures hermeticity, helping the cushion to dampen the vibrations generated.

[0034] REFERENCE NUMBERS

[0035] 1 First roll

[0036] 2 Second roll

[0037] 3 Cutting apparatus

[0038] 4 Welding apparatus

[0039] 10 First fabric

[0040] 11 Inner wall 12 Outer layer

[0041] 14 Side edge

[0042] 15 Top edge

[0043] 17 Front face 20 Weld stitch

[0044] 30 Air pocket

[0045] 32 Inner wall

[0046] 40 Valve

[0047] 41 Inlet 42 Nozzle

[0048] 44 Mounting patch

[0049] 50 Second fabric

[0050] 51 Inner wall

[0051] 52 Outer layer Z Safety zone

Claims

CLAIMS1. An inner bag-free air cushion comprising a first fabric (10) made of polymeric material with a laminated nonwoven inner layer (11) and a woven fabric outer layer (12), characterized by a second fabric (50) made of polymeric material with a nonwoven inner layer (51), environmentally sealed to the first fabric by a thermal welding seam forming an inflatable air pocket (30).

2. An air cushion according to claim 1 , wherein a valve (40) is hermetically fixed to the inner layer (11 , 51) by thermal welding and transfers compressed air from the outside environment into the air pocket (30) through an inlet (41).

3. An air cushion according to any of the preceding claims, wherein the second fabric (50) has a fabric outer layer (52) laminated to the inner layer (51 ).

4. An air cushion according to claim 3, wherein the outer layers (12, 52) are selected from the group consisting of polypropylene tarpaulin, polyethylene, and HDPE materials or combinations thereof.

5. An air cushion according to any of the preceding claims, wherein the inner layers (11 , 51) have a thermoplastic film.

6. An air cushion according to any of the preceding claims, wherein the first and second fabrics (10, 50) are a single-piece laminated fabric folded in half.

7. An air cushion according to any of the preceding claims, wherein the weight of the first and second fabrics (10, 50) are set between 60 gr / cm2and 240 gr / cm2, preferably between 60- 100 gr / cm2.

8. An air cushion according to any of the preceding claims, wherein the lamination thickness of the inner layer (11 , 51) are arranged between 20 microns and 120 microns, preferably between 30 and 70 microns.

9. An air cushion according to any of the preceding claims, wherein the outer layer (12, 52) is made of seamless hose weaving.

10. A method for producing an air cushion according to any of the preceding claims, comprising the steps of providing a first fabric (10) by laminating a nonwoven inner layer (11) onto a woven outer layer (12); aligning a second fabric (50) of the same structure with the nonwoven inner layer (51 ) of the first fabric (10); forming an airtight weld stitch (20) surrounding an air pocket (30) on corresponding faces of the inner layers (11 , 51 ) using a welding apparatus (4).

11. A method for producing an air cushion according to claim 10, wherein the welding apparatus (4) is completely merging the first and second fabrics (10, 50) along the weld stitch (20).

12. A method for producing an air cushion according to claims 10-11 , comprising the step of mounting a valve (40) passing through the outer layer (12) from a mounting patch (44) on the inner layer (11) before the weld stitch (20).

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