Auxiliary air-column frame of muddy land walking board and manufacturing method therefor

Abstract

To provide an auxiliary air-column frame of a muddy land walking board and a manufacturing method therefor which allow a user to stably walk and carry out rescue operations even in a muddy land, and which can be easily transported and collected.SOLUTION: An auxiliary air-column frame 1 of a muddy land walking board comprises an air-column frame body 10 mounted on a muddy land around an installed walking board P, a belt-like part 20 installed to protrude inward around the air-column frame body 10 and restricting mud and water from entering the air-column frame body 10 from a bottom, and a support connection body 30 connecting the belt-like parts 20, supporting the walking board P, and capable of discharging the mud and water in the air-column frame body 10 during the collection.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an auxiliary air column frame for a board for walking on muddy ground and a method for manufacturing the same. [Background technology]

[0002] One of the situations where walking through muddy ground is necessary is rescue operations after a disaster occurs, and the ground can become muddy, particularly during typhoons, heavy rain, tsunamis, landslides, etc., which can hinder rescue operations. Traditionally, at disaster sites, temporary walkways have been created by simply laying out planks of wood (such as 6x6 boards) or plywood (910 x 1820 mm) on muddy ground. Patent Document 1 also discloses a floating pier that allows people to walk on water, in which two rows of float-like bodies are attached to the underside of a plate-like body made of multiple rectangular plates arranged lengthwise, and the inflated float-like bodies are floated on the water surface, allowing people to walk on the plate-like body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-095838 Summary of the Invention [Problem to be solved by the invention]

[0004] Until now, when using planks to walk on muddy ground, the planks have been difficult to hold and transport because they are not processed. When they are lined up in the mud, mud creeps up from the surrounding area, making it difficult to distinguish between the surrounding area and the planks, leading to missteps, and requiring constant attention to one's footing, making it difficult to carry out rescue operations and other tasks efficiently. Furthermore, when it comes to retrieving the materials, there are problems such as the planks being difficult to find because they are buried in mud, and the mud on the planks makes them very heavy, making it hard work. Furthermore, when a floating pier is used in muddy ground, a space is formed between the boards and the muddy ground due to the float-like bodies, making it impossible to set up in a stable state, and making it difficult to walk safely or carry out rescue operations and other tasks.

[0005] The present invention has been made in consideration of such problems, and aims to provide an auxiliary air column frame for a board material for walking on muddy ground, which allows stable walking and rescue operations even in muddy ground, and which is easy to transport and retrieve, and a method for manufacturing the same. [Means for solving the problem]

[0006] In order to solve the above problems, the auxiliary air column frame of the muddy walking board according to the first aspect of the present invention is: an air column frame that surrounds the walking board to be attached and is placed on the muddy ground; a band-shaped portion that protrudes from the inner periphery of the air column frame and restricts the intrusion of mud and water into the air column frame from the bottom; a support connecting body that connects the strips to support the walking board and can discharge mud and water from the air column frame when retrieving the board; It is characterized by:

[0007] It is preferable that the air column frame body is formed of one air column chamber or multiple air column chambers, bent or connected to a shape that corresponds to the outer shape of the walking board, and is annular in shape to hold the attached walking board.

[0008] The air column frame preferably has a diameter that allows the object to be pulled in without mud and water creeping up and lifting it out of the muddy ground.

[0009] It is preferable that the air column frame be provided with a handle so that it can be carried with the walking board attached.

[0010] The air column frame body preferably includes connecting members that connect adjacent auxiliary air column frames to each other.

[0011] It is preferable that the air column frame be made of a composite sheet material in which a rubber layer is laminated onto a thermoplastic polyurethane layer, and that the composite sheet materials be overlapped and joined together in the circumferential direction, and that the end faces be butted together and joined by heat welding via a thermoplastic polyurethane layer patch in the longitudinal direction.

[0012] The walking boards attached to the air column frame are preferably made of waterproof plywood used for concrete processing.

[0013] Further, a manufacturing method of an auxiliary air column frame for a board for walking on muddy ground according to a second aspect of the present invention includes: a step of attaching a reinforcing sheet material to the inner surface of a composite sheet material having a width that is approximately the sum of the circumferential length of the air column and the width of the band-shaped portion, and a length that is approximately the perimeter of the walking board, in such a way that it corresponds to the position of the corner of the walking board; connecting the ends of the composite sheet material to form an annular sheet; a step of folding the annular sheet in the width direction and joining the folded sheet together, leaving the strip-shaped portion, to form an air column frame; a step of forming a triangular corner holding portion that holds the air column frame in a folded shape on the band-shaped portion of the outer portion of the air column frame to which the reinforcing sheet material is attached; and connecting a support connector that supports the walking board between the band-shaped portions. It is characterized by:

[0014] The composite sheet material and the reinforcing sheet material are preferably made of a composite sheet material in which a rubber layer is laminated on a thermoplastic polyurethane layer.

[0015] The composite sheet material is preferably joined by butting the ends together and overlapping the thermoplastic polyurethane sheet layer with a patch, and then heat welding the end portions together. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an auxiliary air column frame for a board for walking on muddy ground, which allows stable walking and rescue operations even in muddy ground and allows easy transportation and recovery, and a method for manufacturing the same. [Brief explanation of the drawings]

[0017] [Figure 1] This is one embodiment of the auxiliary air column frame of the muddy walking board of the present invention, where (a) is a schematic oblique view of the air column frame body only, and (b) is a schematic oblique view of the auxiliary air column frame showing the walking board disassembled. [Figure 2] 1A is a plan view, FIG. 1B is a cross-sectional view taken along line AA in FIG. 1A, and FIG. 1C is a cross-sectional view taken along line BB in FIG. 1A. [Figure 3] 1A to 1D show the first half of a method for manufacturing an auxiliary air column frame for a board for walking on muddy ground according to an embodiment of the present invention. [Figure 4] 1A to 1D are process diagrams of the latter half of an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the auxiliary air column frame for a board for walking on muddy ground and a method for manufacturing the same of the present invention will be described in detail with reference to the drawings. As shown in Figure 1, the auxiliary air column frame 1 for a muddy-terrain walking board of the present invention comprises an air column frame body 10 that surrounds the attached walking board P and is placed on the muddy ground, strips 20 that protrude inside the air column frame body 10 and restrict the ingress of mud and water into the air column frame body 10 from the bottom, and support connectors 30 that connect the strips 20 to support the walking board P and enable the mud and water inside the air column frame body 10 to be discharged when it is retrieved. This auxiliary air column frame 1 for a muddy-terrain walking board (hereinafter simply referred to as air column frame 1) is used in rescue operations and the like to attach prefabricated (unprocessed) boards such as 606 boards or plywood (910 x 1820 mm) as walking boards P as they are, forming the air column frame for constructing a walkway.

[0019] This air column frame 1 is made of a composite sheet material, for example, an outer rubber layer and a thermoplastic polyurethane layer, and the thermoplastic polyurethane layer is used to join the air column frame body 10 by thermal welding or adhesive bonding.

[0020] Here, heat welding includes, but is not limited to, heat sealing and high-frequency welding. High-frequency welding heats only the welding portion of the heated object, allowing welding in a short time and without thermally affecting the non-welded portion. Furthermore, since the heated object is heated uniformly from the inside, the welding strength is excellent, and stable welding processing can be performed with a heating time of just a few seconds. Furthermore, it is a very clean processing method that does not generate environmentally hazardous substances during or after processing. Heat welding using a high-frequency welder is more preferable in terms of preventing the heat from affecting the non-welded portion.

[0021] The air column frame body 10 of the air column frame 1 is cylindrical and surrounds the walking board P, placed on muddy ground, and is inflated with air. The air column frame body 10 is formed, for example, in a rectangular shape, and its diameter d is set so that when placed on muddy ground, mud and water do not creep up and people or objects to be rescued can be pulled in without being lifted. The diameter d of the air column frame 10 is, for example, 50 mm or more and 300 mm or less. If the diameter d is too small, such as 50 mm or less, it will not function as a protective barrier against mud and water. If the diameter d is larger than 300 mm, people or objects to be rescued cannot be pulled in from muddy ground into the air column frame 1 and must be lifted. The diameter d of the air column frame 10 is preferably 100 to 200 mm, and more preferably 100 to 150 mm.

[0022] The perimeter of the air column frame 10 is set so that the walking boards P, such as plywood, mounted inside the air column frame 10 will not come off even if the frame is turned upside down. For example, if the diameter d of the air column frame 10 is 100 mm for a 910 x 1820 mm plywood panel, the perimeter along the center line of the air column frame 10 is approximately 1020 mm (910 + approximately 100 mm) for the short sides, and approximately 2000 mm (1820 + approximately 100 mm) for the long sides, resulting in a perimeter of (approximately 1020 + approximately 2000) x 2 = approximately 6040 mm. This allows the walking boards P to be mounted so that they fit in and get caught on the perimeter of the expanded air column frame 10 by approximately 20 mm, as shown in Figure 2, and the expansion of the air column frame 10 helps to maintain the mounted state.

[0023] As shown in FIG. 1, the air column frame 10 is formed from a single air column chamber 11, with four corners folded to form a rectangular frame. Alternatively, the air column frame 10 may be formed from multiple air column chambers 11. Although not shown, two independent air column chambers may be connected to form two air column chambers, each with two corners formed to form a rectangular air column frame. The number of air column chambers 11 is not limited to the above example and may be set as appropriate, taking into consideration the effort required to inflate and manufacture the air column chambers 11. Each air column chamber 11 is provided with at least one air valve 12 to allow the air column chamber 11 to be inflated or deflated.

[0024] The air column frame 1 is provided with a fin-shaped band portion 20 that protrudes inward from the bottom of the air column frame body 10 and prevents mud and water from entering the air column frame body 10 from the bottom. 2, the strip-like portion 20 is formed in a sheet shape from the bottom of the center line of the air column frame body 10, with a protrusion amount (protrusion width) of approximately 100 mm. This prevents mud, water, etc. from entering the inside of the top surface of the air column frame body 10 from the bottom of the air column frame body 10 as much as possible. In addition, by attaching a walking board P between the strip-like portion 20 and the expanded air column frame body 10, the walking board P can be held on the air column frame body 10 in cooperation with the support connector 30, which will be described later.

[0025] The air column frame 1 has an air column frame body 10 that is rectangular and matches the shape of the walking board P. The short sides and long sides of the rectangular band-shaped parts 20 are connected in a cross shape by band-shaped support connectors 30 between the centers of the band-shaped parts 20. As a result, the inside part of the band-shaped parts 20 at the bottom of the air column frame 1 is not completely blocked, and four rectangular through holes 31 separated by the support connectors 30 are formed in the bottom of the air column frame body 10.

[0026] As shown in FIGS. 1 and 2, the air-column frame 10 is provided with handles 40 on its short sides. More specifically, metal rings 41, e.g., D-shaped rings, are attached to two locations on the short sides of the air-column frame 10 by gluing them via a fixing sheet material, and the metal rings 41 are connected by handles 40 consisting of a string-like belt member. This allows the air-column frame 10 to be easily transported with the walking board P attached to it using the belt member as the handle 40. Furthermore, string-like connecting members 50 are tied to the metal rings 41 of the handles 40, and the string-like connecting members 50 are passed through the metal rings 41 of adjacent air-column frames 1 and connected with rod-like fasteners (duffle buttons: toggle buttons) 51, allowing the air-column frames 1 to be connected to each other. This allows the air-column frames 1 to be connected more reliably to each other without being affected by mud getting caught, compared to when using only buckles or string-like connecting members 50.

[0027] In the air column frame 1, which comprises an air column frame body 10 filled with air and formed into a rectangle, a strip-like portion 20 on the inside of the bottom of the air column frame body 10, and a support connector 30 connecting the strip-like portions 20, a walking board material P such as plywood is attached to the inside of the air column frame body 10 before it is inflated, and when air is pumped in through the air valve 12 to inflate it, the walking board material P is held between the strip-like portion 20 and the inflated air column frame body 10. Next, the air column frame 1 is lifted by the handles 40, and the air column frame 1 with the walking board P attached is placed on the muddy ground. When placed on the muddy ground, the bottom periphery of the air column frame body 10 is sealed with the strip-shaped portion 20, which minimizes the intrusion of mud and water from the bottom, and also prevents mud and water from creeping up from the top of the air column frame body 10. This allows a walkway to be constructed on muddy ground using the air column frame 1 and the walking board P, and the boundary between the muddy ground and the walking board P is made clear by the air column frame body 10, allowing people to walk safely on the walking board P. If the walkway needs to be extended further, a similar air column frame 1 is carried to an adjacent muddy area, and the string-like connecting member 50 is passed through the metal ring 41 of the handle 40 and connected with a rod-like fastener 51. In this way, the air column frames 1 can be connected side by side, and the walkway can be extended and constructed.

[0028] Also, when retrieving the air column frame 1, by lifting the air column frame 1 using the handle 40, the walking board P can be lifted together with the air column frame body 10, and even if mud or water is inside the walking board P, it is discharged through the through holes 31 between the support connecting bodies 30, so it can be retrieved and transported without becoming heavy.

[0029] Next, one embodiment of a method for manufacturing the air column frame 1 of the board for walking on muddy ground according to the present invention will be described in accordance with the steps shown in FIGS. The air column frame 1 is made of a composite sheet material 60, for example, a rubber layer on the surface and a resin sheet layer on the backside that can be heat-sealed, and the resin layer on the backside is joined using heat fusion, or the rubber layer 61 on the surface is joined by adhesive or the like to form the air column frame body 10.

[0030] As shown enlarged in FIG. 3(a), the air column frame 1 uses a composite sheet material 60 in which a rubber layer 61 on the surface, a heat-sealable resin sheet layer 62 on the back, and an intermediate reinforcing layer 63 are laminated. For example, a thermoplastic polyurethane (TPU) layer is used as the heat-sealable resin sheet layer 62. Hereinafter, the resin sheet layer 62 will be referred to as the thermoplastic polyurethane layer 62, although this is not intended to be limiting. Furthermore, for example, a nylon fabric layer is used as the reinforcing layer 63. Hereinafter, the reinforcing layer 63 will be referred to as the nylon fabric layer 63, although this is not intended to be limiting.

[0031] The composite sheet material 60 is joined and bonded using heat fusion, adhesive, etc. to form the air column frame 1.

[0032] The manufacturing method of the air column frame 1 is a step S1 of attaching a reinforcing sheet material 70 to the inner surface of a composite sheet material 60 having a width approximately equal to the circumferential length of the air column frame body 10 plus the width of the band-shaped portion 20, and a length approximately equal to the perimeter of the walking board P, in correspondence with the positions of the corners of the walking board P; a step S2 of connecting the ends of the composite sheet material 60 to form an annular sheet 80; a step S3 of folding the annular sheet 80 in the width direction to form a cylindrical air column frame 10 while leaving the band-shaped portion 20; a step S4 of forming triangular corner holding portions 21 that hold the air column frame 10 in a folded shape on the band-shaped portion 20 of the outer portion of the air column frame 10 to which the reinforcing sheet material 70 is attached; and step S5 of connecting the support connectors 30 that support the walking board P between the band-like portions 20. Each step will be described below.

[0033] 3(a), the first step S1 is to prepare a composite sheet material 60, and set it to a width that is the circumferential length of the air column frame 10 plus the length of the strip portion 20, and a length that is the perimeter of the walking board material P. In the illustrated example, in the length direction, a wide composite sheet material 60 is divided into two pieces, each with a length that takes into account the extra length required for joining, and these pieces are joined together for use. An air valve 12 for supplying and discharging air into the air column chamber 11 is attached to the composite sheet material 60 in advance. Furthermore, reinforcing sheet materials 70 are attached to the composite sheet material 60 at four locations corresponding to the corners of the walking board P. The reinforcing sheet materials 70 are cut using the same material as the composite sheet material 60, and are thermally fused together with the thermoplastic polyurethane layers 62 on the back surfaces facing each other. The reinforcing sheet material 70 has gaps formed at the top and bottom in the width direction so that when the air column frame 10 is joined into a cylindrical shape, the sheets do not overlap and interfere with each other.

[0034] In the second step S2, as shown in Figures 3(b) and 3(c), the composite sheet material 60 is joined in the lengthwise direction to form a ring-shaped sheet 80. The lengthwise direction of the composite sheet material 60 is joined at one point to form a single sheet. The two joints are formed by butting the ends of the composite sheet material 60 together, placing a thermoplastic polyurethane sheet of the same material that can be heat-welded on the inside of the butted portion as a patch 71, and then heat welding the ends together, as shown in the enlarged partial view in Figure 3(c). By joining the two points of the composite sheet material 60, the ring-shaped sheet 80 is formed (see Figure 3(d)).

[0035] In the third step S3, as shown in FIG. 4(a), the annular sheet 80 is folded in the width direction to form a cylindrical air column frame 10, leaving the band-like portion 20. When the annular sheets 80 are overlapped in the width direction, the thermoplastic polyurethane layers 62 on the back surfaces overlap each other, and can be heat-welded as a cross-joint of the same material.

[0036] In the fourth step S4, as shown in Figure 4(b), a triangular corner holding portion 21 is formed on the band-shaped portion 20 of the outer part of the air column frame body 10 to which the reinforcing sheet material 70 is attached, to hold the air column frame body 10 in its folded shape. A corner holding portion 21 in the shape of an isosceles right triangle with the corner at the apex is cut out in advance from the band-shaped portion 20 in the portion where the reinforcing sheet material 70 has been attached beforehand to the inside of the annular sheet 80, and the two right-angled sides are joined by welding or the like. This forms a right-angled corner with the apex of the corner holding portion 21 as the center. Note that the corner holding portion 21 may also be cut out after the two right-angled sides have been joined by welding or the like. Furthermore, although not shown, the inside of the air column frame 1 in the portion where the two right-angled sides are welded is reinforced by adhering or welding the reinforcing sheet material 70 or the like across it. By forming corner holding parts 21 at four places on such a circular or annular sheet 80, when air is pumped into the air column frame 10 from the air valve 12 to inflate it, the corners of the air column frame 10 are restrained and bent at right angles.

[0037] In the fifth step S5, support connectors 30 are connected between the strips 20 to support the walking planks P. The support connectors 30 connect the opposing central portions of the strips 20 that protrude inward within the air-column frame 10. Composite sheet materials 60 made of the same material as the air-column frame 10 and the strips 20, each approximately 100 mm wide, are arranged in a cross shape, and the strips 20 and the composite sheet materials 60, such as thermoplastic polyurethane layers, are attached by thermal fusion. The intersections of the strips 20 are bonded with adhesive or left unbonded. This leaves the inside of the bottom strips 20 of the air-column frame 1 completely unobstructed, and four rectangular through-holes 31 separated by the support connectors 30 are formed in the bottom of the air-column frame 10.

[0038] Furthermore, as a sixth step, although not shown, handles 40 are arranged on the air column frame 10 as shown in Figures 1 and 2. That is, metal rings 41 are attached at two locations on the short sides by gluing them via a fixing sheet material, and the two metal rings 41 are connected by handles 40 made of a string-like belt member. Also, a string-like connecting member 50 is tied to the metal rings 41 of the handle 40, and the string-like connecting member 50 is passed through the metal rings 41 of adjacent air column frames 1 and connected with rod-like fasteners (duffle buttons: toggle buttons) 51, so that the air column frames 1 can be connected to each other. With such handles 40 and connecting members 50, the air column frame 10 can be easily transported with the walking board P attached, and can be securely connected without being affected by mud getting caught in it.

[0039] As described above, according to the manufacturing method of the auxiliary air column frame for the board material for walking on muddy ground, the air column frame body 10 can be easily manufactured using the composite sheet material 60, and by attaching a board material such as plywood as the walking board material P, rescue operations and walking on muddy ground can be carried out safely. In addition, by combining joining using a cross joint (cross joint) and joining using heat fusion in which a patch cloth 71 is applied to the butt joint, the joining of the composite sheet material 60 can ensure joint strength and airtightness.

[0040] As specifically explained in the above embodiments, the air column frame 1 of the muddy walking board of the present invention comprises an air column frame body 10 that surrounds the attached walking board P and is placed on the muddy ground, a strip-shaped portion 20 that protrudes inside the periphery of the air column frame body 10 and prevents mud and water from entering the air column frame body 10 from the bottom, and a support connecting body 30 that connects the strip-shaped portions 20 to support the walking board P and can drain mud and water from the air column frame body 10 when it is retrieved. According to this configuration, by attaching the walking plank P to the inside of the air column frame body 10 of the air column frame 1, even when placed on muddy ground, the boundary between the walking plank P and the muddy ground can be clearly defined, making it possible to safely walk on the walking plank P or perform rescue operations. In addition, when retrieving the walking plank P, mud and water can be discharged through the through holes 31 of the support connecting body 30 simply by lifting it up, and it can be easily retrieved and transported without becoming heavy.

[0041] In the air column frame 1 of the muddy walking board of the present invention, the air column frame body 10 is formed of one air column chamber 11 or multiple air column chambers 11, and is bent or connected to a shape that corresponds to the outer shape of the walking board P, and is made into a ring shape that holds the attached walking board P. With this configuration, preparation can be easily carried out by inflating the air column frame 10 with air, and rescue operations can be started quickly by assembling standardized boards such as ready-made plywood as walking boards P. In addition, it is easy to secure walking boards P in the vicinity of where rescue operations will be carried out, and only the lightweight air column frame 1 needs to be transported.

[0042] In the air column frame 1 of the board for walking on muddy ground of the present invention, the air column frame body 10 has a diameter d that prevents mud and water from creeping up and allows an object to be pulled in without being lifted from the muddy ground. With this configuration, when carrying out rescue operations in muddy areas, rescuers or large objects do not need to be lifted, but can simply be pulled in, thereby reducing the physical exertion required for the work.

[0043] In the air column frame 1 of the muddy terrain walking board of the present invention, the air column frame body 10 is provided with a handle 40 so that it can be carried with the walking board P attached. This configuration allows for easy lifting, transport, and retrieval, allowing for quick use.

[0044] In the air column frame 1 of the board for walking on muddy ground of the present invention, the air column frame body 10 is provided with connecting members 50 that connect the adjacent air column frames 1 together. With this configuration, adjacent air column frames 10 can be connected with the connecting members 50, making it easy to extend the walkway and expand the range of rescue operations.

[0045] In the air column frame 1 of the muddy walking board of the present invention, the air column frame body 10 is composed of a composite sheet material 60 in which a rubber layer 61 is laminated on a thermoplastic polyurethane layer 62, and the composite sheet materials 60 are overlapped and joined together in the circumferential direction, and in the longitudinal direction, the end faces are butted together and heat-welded via a thermoplastic polyurethane layer patch 71 to form a ring shape. According to this configuration, by using the composite sheet material 60 and combining cross-jointing and butt-jointing of the end faces, it is possible to form an air column frame 10 that is highly airtight and strong.

[0046] In the air column frame 1 of the muddy terrain walking board of the present invention, the walking board P attached to the air column frame body 10 is made of standard plywood used for concrete processing that has been treated to be waterproof. According to this configuration, the walking board material P can be procured without prior preparation, and no processing is required, which makes it easier to respond at the scene of rescue operations.

[0047] In addition, the manufacturing method of the auxiliary air column frame for the muddy walking board of the present invention includes the steps of attaching a reinforcing sheet material 70 to the inner surface of a composite sheet material 60, the composite sheet material 60 having a width approximately equal to the circumferential length of the air column frame body 10 plus the width of the band-shaped portion 20, and having a length approximately equal to the peripheral length of the walking board P, so as to correspond to the position of the corners of the walking board P; connecting the ends of the composite sheet material 60 to form an annular sheet 80; folding the annular sheet 80 widthwise to form a cylindrical air column frame body 10, leaving the band-shaped portion 20; forming triangular corner holding portions 21 on the band-shaped portion 20 of the outer portion of the air column frame body 10 to which the reinforcing sheet material 70 is attached, which hold the air column frame body 10 in its folded shape; and connecting a support connector 30 that supports the walking board P between the band-shaped portions 20. With this configuration, the air column frame 10 can be easily manufactured using the composite sheet material 60, and by attaching a board material such as plywood as a walking board material P, rescue operations and walking in muddy areas can be carried out safely. In addition, by combining joining using a cross joint (cross joint) and joining using heat fusion in which a patch cloth 71 is applied to the butt joint, the joining of the composite sheet material 60 can ensure joint strength and airtightness.

[0048] In the manufacturing method of the auxiliary air column frame of the muddy walking board of the present invention, the composite sheet material 60 and the reinforcing sheet material 70 are made of the composite sheet material 60 in which a rubber layer 61 is laminated on a thermoplastic polyurethane layer 62 . According to this configuration, the thermoplastic polyurethane layers 62 can be joined together by heat fusion, and by combining butt joints and crooked joints, it is possible to ensure bonding strength and airtightness.

[0049] In the manufacturing method of the auxiliary air column frame of the muddy walking board of the present invention, the composite sheet material 60 is joined by butting the ends together and overlapping the thermoplastic polyurethane sheet layer patch 71 and heat welding it. According to this configuration, the pieces can be butted together and welded via the patch cloth 71, and the joint can be kept flat.

[0050] The present invention is not limited to the above-described embodiments, and each invention can be combined to provide its own effects. [Explanation of symbols]

[0051] 1. Auxiliary air column frame for muddy walking boards (air column frame) 10 Air column frame 11 Air column chamber 12 Air valve 20 Belt 21 Corner holding part 30 Support connection 31 Through hole 40 Handle 41 Metal Ring 50 Connecting member 51 Rod-shaped fastener 60 Composite Sheet Material 61 Rubber layer 62 Resin sheet layer (thermoplastic polyurethane layer) 63 Reinforcement layer (nylon fabric layer) 70 Reinforcement sheet material 71 Patch (for heat welding) 80 Circular Sheet P Walking board d Diameter of the air column frame

Claims

1. an air column frame that surrounds the walking board to be attached and is placed on the muddy ground; a band-shaped portion that protrudes from the inner periphery of the air column frame and restricts the intrusion of mud and water into the air column frame from the bottom; a support connecting body that connects the strips to support the walking board and can discharge mud and water from the air column frame when retrieving the board; An auxiliary air column frame for a board for walking on muddy ground, characterized by:

2. The air column frame is formed of one air column chamber or a plurality of air column chambers, and is bent or connected to a shape corresponding to the outer shape of the walking board, and is formed into an annular shape to hold the attached walking board.

2. The auxiliary air column frame of the muddy walking board according to claim 1.

3. The air column frame has a diameter that allows the object to be pulled in without mud and water creeping up and lifting it out of the muddy ground.

2. The auxiliary air column frame of the muddy walking board according to claim 1.

4. The air column frame is made of a composite sheet material in which a rubber layer is laminated on a thermoplastic polyurethane layer, and the composite sheet materials are overlapped and joined together in the circumferential direction, and are joined by butting the end faces together in the longitudinal direction and heat welding via a thermoplastic polyurethane layer patch.

4. An auxiliary air column frame for a board for walking on muddy ground according to claim 1, 2 or 3.

5. a step of attaching a reinforcing sheet material to the inner surface of a composite sheet material having a width that is approximately the sum of the circumferential length of the air column and the width of the band-shaped portion, and a length that is approximately the perimeter of the walking board, in such a way that it corresponds to the position of the corner of the walking board; connecting the ends of the composite sheet material to form an annular sheet; a step of folding the annular sheet in the width direction and joining the folded sheet together, leaving the strip-shaped portion, to form an air column frame; forming triangular corner holding portions on the band-shaped portion of the outer portion of the air column frame to which the reinforcing sheet material is attached, the triangular corner holding portions holding the air column frame in a folded shape; and connecting a support connector that supports the walking board between the band-shaped portions. A method for manufacturing an auxiliary air column frame for a board for walking on muddy ground.

6. The composite sheet material and the reinforcing sheet material are made of a composite sheet material in which a rubber layer is laminated on a thermoplastic polyurethane layer. A method for manufacturing an auxiliary air column frame for a board for walking on muddy ground according to claim 5.

7. The composite sheet material is joined by butting the ends together and overlapping the thermoplastic polyurethane sheet layer with a patch, and then thermally welding the end pieces together. A method for manufacturing an auxiliary air column frame for a board for walking on muddy ground according to claim 6.

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