Impact absorbing structure and method for manufacturing an impact absorbing structure

Abstract

To provide a shock absorbing structure having a single layer structure that achieves a required performance, such as shock absorption, productivity, light weight, and conforming deformation, at a high level, and a method for manufacturing the shock absorbing structure.SOLUTION: A top of head shock absorbing sheet A1 includes a plurality of polystyrene foam spheres 10 and a plurality of mesh fabrics 20. The mesh fabrics 20 have storage line joints 21 that are joined in a line at equal intervals with a width of approximately 1 / 2 a circumferential length of a selected polystyrene foam spheres 10, and outer periphery line joints 22 that are joined in a line around an outer periphery of the polystyrene foam sphere 10 that is positioned outermost when multiple polystyrene foam spheres 10 are stored. The polystyrene foam spheres 10 are stored and arranged in each of a plurality of rows of storage spaces 40 formed by storage line joints 21 and outer circumferential line joints 22 of the overlapped mesh fabrics 20, and the polystyrene foam spheres 10 in adjacent rows are alternately arranged with a shift of approximately a radius.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a shock absorption structure and a method for manufacturing the shock absorption structure.

Background Art

[0002] Conventionally, there is known a shock absorption structure including a plurality of elastic spherical bodies that are spherical and elastically deformed according to the magnitude and direction of an external force applied from the outside, and a soft coupling structure provided between the elastic spherical bodies in which the plurality of elastic spherical bodies are assembled in a planar shape (see Patent Document 1). Further, there is known a shock absorption structure in which a plurality of rows of spherical bodies having through holes are laminated in the through direction of the through holes, and each spherical body is arranged such that the axis of the through hole of each spherical body in the upper layer coincides with the axis of the through hole of the corresponding spherical body in the lower layer (see Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, currently, traffic accidents of bicycle and electric kick scooter riders have become a social problem, and in particular, social needs and interests in protecting the heads of riders are increasing. For bicycle riders, with the amendment of the Road Traffic Law on April 1, 2023, in addition to children, adults are also obliged to wear head protectors. Further, for electric kick scooter riders, even for small-sized specified motorized bicycles with a low-speed specification having a maximum speed of 20 km / h or less, wearing a head protector is an obligation of due diligence.

[0005] In contrast, the impact-absorbing structure described in Patent Document 1 is a single-layer structure that uses multiple hollow polyethylene beads as a cushioning material and assembles them in a planar shape by soft bonding, resulting in low impact absorption. Therefore, it has the problem of not being able to perform the head protection function required when applied to head protection equipment for high-energy collision accidents such as those involving cyclists. Similarly, the impact-absorbing structure described in Patent Document 2 would require, for example, a laminated structure of three or more layers to ensure the impact absorption required when applied to head protection equipment for high-energy collision accidents such as those involving cyclists. As a result, an impact-absorbing structure with a laminated structure of three or more layers leads to a significant increase in the number of spherical cushioning material parts, resulting in decreased productivity and reduced lightness. Furthermore, the impact-absorbing structure described in Patent Document 2 has multiple spherical cushioning materials with through holes arranged in both vertical and horizontal rows. Therefore, unless a certain amount of gap is provided between the spherical cushioning materials, it becomes a structure in which the surface shape only changes around one axis, either the vertical or horizontal axis. Therefore, impact-absorbing structures with a laminated structure of three or more layers have the problem of poor shape conformability to the head, which is rounded in all directions, when applied to head protection equipment, for example.

[0006] This invention has been made in view of the above-mentioned problems, and aims to provide a single-layer shock-absorbing structure and a method for manufacturing the shock-absorbing structure that achieves the required performance of shock absorption, productivity, lightness, and conforming deformation at a high level. [Means for solving the problem]

[0007] The shock-absorbing structure for mitigating external forces according to the present invention comprises a plurality of spherical cushioning materials that achieve the target shock absorption performance through a single-layer structure, and a plurality of overlapping fabrics having an area large enough to encompass the area of ​​human protection provided by the spherical cushioning materials. The fabrics have storage line joints that are joined linearly at equal intervals with a width of approximately half the circumference of the selected spherical cushioning materials, and outer periphery line joints that are joined linearly around the outer periphery of the outermost spherical cushioning material when the plurality of spherical cushioning materials covering the protection area are stored inside. The spherical cushioning materials are stored in each of the plurality of storage spaces formed by the storage line joints and outer periphery line joints of the overlapping fabrics, and the spherical cushioning materials in adjacent rows are arranged alternately with an offset of approximately the radius. The aforementioned spherical cushioning material is selected based on a pre-impact test or simulated impact test in which a head impactor having the same rigidity as a human head is free-dropped from a height position according to the JCF safety standards toward a collection of cushioning materials arranged in a single layer. The test results using 3-axis composite acceleration are then determined to be below the specified JCF safety standards, and the cushioning material is selected based on its shape and material.

[0008] The present invention provides a method for manufacturing an impact-absorbing structure that mitigates external forces, comprising a spherical cushioning material selection procedure, a protection area setting procedure, a fabric overlapping procedure, a storage space formation procedure, a spherical cushioning material insertion procedure, and a finishing procedure. The spherical cushioning material selection procedure involves selecting a spherical cushioning material that can achieve the target impact absorption performance with a single-layer structure. The protection area setting procedure defines the area of ​​the human body to be protected by the spherical cushioning material. The fabric overlapping procedure involves preparing and overlapping multiple pieces of fabric having an area that encompasses the defined protection area. The storage space formation procedure involves joining the overlapped fabrics with equally spaced storage lines that are approximately half the circumference of the selected spherical cushioning material, thereby forming multiple rows of storage spaces for the spherical cushioning material. The spherical cushioning material insertion procedure involves inserting the selected spherical cushioning material into each of the multiple rows of storage spaces, arranging the spherical cushioning materials in adjacent rows alternately with an offset of approximately the radius. The finishing procedure involves inserting the spherical cushioning material until the protective area is covered, joining it with the outermost spherical cushioning material along the outermost outermost line, and removing any excess fabric along the cut line. The aforementioned spherical cushioning material is selected based on a pre-impact test or simulated impact test in which a head impactor having the same rigidity as a human head is free-dropped from a height position according to the JCF safety standards toward a collection of cushioning materials arranged in a single layer. The test results using 3-axis composite acceleration are then determined to be below the specified JCF safety standards, and the cushioning material is selected based on its shape and material. [Effects of the Invention]

[0009] The present invention provides a single-layer shock-absorbing structure and a method for manufacturing the shock-absorbing structure that achieves the required performance characteristics of shock absorption, productivity, lightness, and conforming deformation at a high level. Furthermore, while employing a single-layer structure for shock absorption, it can satisfy the target shock absorption performance, which is the JCF safety standard. [Brief explanation of the drawing]

[0010] [Figure 1] This shows an example (cross-sectional view) of the application of the top-of-the-head impact-absorbing sheet of Example 1 to a head protection device. [Figure 2] This shows a plan view of the head impact absorbing sheet of Example 1. [Figure 3] Figure 2 shows a cross-sectional view of the top of the head impact absorbing sheet of Example 1, shown by line II. [Figure 4] The polystyrene foam sphere selected for the head impact absorption sheet in Example 1 is shown. [Figure 5] The test conditions for the hypothetical impact test on the polystyrene foam sphere are shown. [Figure 6] This shows a sample of the cushioning material used in the simulated crash test. [Figure 7] The results of a hypothetical impact test on a polystyrene foam sphere are shown. [Figure 8] The procedure for manufacturing the head impact absorbing sheet of Example 1 is shown below. [Figure 9] This diagram illustrates the procedure for creating storage spaces in the sheet manufacturing process. [Figure 10] This diagram illustrates the procedure for inserting spherical cushioning material as part of the sheet manufacturing process. [Figure 11] This diagram illustrates the finishing steps in the sheet manufacturing process. [Figure 12] The table below summarizes the characteristics of hard-type (one-piece molded) head protection. [Figure 13] The table below summarizes the features of hard-type (foldable) head protection. [Figure 14] The table below summarizes the characteristics of soft-type (layered) head protection devices. [Figure 15]A table summarizing the features of the head protector incorporating the sheet of Example 1 is shown. [Figure 16] A spherical cushion material laminated sample used in the comparative test of the simulated collision test is shown. [Figure 17] The comparative test results of the simulated collision tests of the foamed sample, two-layer sample, and three-layer sample are shown. [Figure 18] An explanatory reference diagram of the action of the head impact absorbing sheet of the invention technology is shown. [Figure 19] An explanatory reference diagram of the action of the head impact absorbing sheet of the comparative technology is shown. [Figure 20] A plan view of the head side impact absorbing sheet of Example 2 is shown. [Figure 21] An external view of the head side impact absorbing sheet of Example 2 is shown. [Figure 22] A perspective view of the head protector incorporating the head side impact absorbing sheet of Example 2 is shown. [Figure 23] An external view of the head overall impact absorbing sheet of Example 3 is shown. [Figure 24] An example of a head protector incorporating the head overall impact absorbing sheet of Example 3 is shown. [Figure 25] A plan view of the head overall impact absorbing sheet of Example 4-1 is shown. [Figure 26] An external view of the head overall impact absorbing sheet of Example 4-1 is shown. [Figure 27] A plan view of the head overall impact absorbing sheet of Example 4-2 is shown. [Figure 28] An external view of the head overall impact absorbing sheet of Example 4-2 is shown. [Figure 29] An example of simply putting the head top impact absorbing sheet of Example 1 into the hat body is shown. [Figure 30] An example of attaching a chin strap to the head overall impact absorbing sheet of Example 3 is shown.

Mode for Carrying Out the Invention

[0011] The mode for carrying out the impact absorbing structure and the manufacturing method of the impact absorbing structure of the present invention will be described as follows based on Examples 1 to 4 shown in the drawings.

[0012] The impact-absorbing structures manufactured by the methods described in Examples 1 to 4 are head impact-absorbing structures that protect the head of the human body, and are applied as impact-absorbing sheets to soft-type head protection devices worn on the heads of riders of bicycles, kick scooters (small specific mopeds), etc. [Examples]

[0013] Example 1 is an example of a head impact absorbing sheet A1 (an example of an impact absorbing structure) with the head as the protected area of ​​the human body, and a method for manufacturing the head impact absorbing sheet A1.

[0014] [Configuration of head protection device (Figure 1)] Head protection devices B1 to B3 are internally constructed head protection helmets with a crown impact absorbing sheet A1 incorporated into the inner surface of the hat body C1 to C3. Head protection device B1, as shown in Figure 1(a), incorporates the crown impact absorbing sheet A1, manufactured by the method described later, into the inner surface of a newsboy cap-type hat body C1 made of flexible fabric. Head protection device B2, as shown in Figure 1(b), incorporates the crown impact absorbing sheet A1, manufactured by the method described later, into the inner surface of a cloche-type hat body C2 made of flexible fabric. Head protection device B3, as shown in Figure 1(c), incorporates the crown impact absorbing sheet A1, manufactured by the method described later, into the inner surface of a bandana-type hat body C3 made of a patterned, dyed square piece of cotton or the like, shaped to wrap around the head.

[0015] Furthermore, various methods may be used to incorporate and secure the crown impact-absorbing sheet A1 into the hat body C1-C3. Examples of such methods include forming a sheet pocket in the protective area on the inner surface of the hat body C1-C3 to store the sheet, or securing it to the protective area on the inner surface of the hat body C1-C3 by sewing or other means.

[0016] Head protection device B4 is an external-type head protection helmet in which a crown impact absorbing sheet A1 is attached to the outside of a hat body C4. As shown in Figure 1(d), head protection device B4 has a crown impact absorbing sheet A1, manufactured by the method described later, attached to the outside of a hat body C4 such as a baseball cap. As shown in Figure 1(d), this head protection device B4 may be left exposed to the outside, but as shown in Figure 1(e), the outside of the crown impact absorbing sheet A1 may be covered with a cloth fabric C5 to prevent the sheet from being exposed to the outside.

[0017] [Configuration of the head impact absorbing sheet (Figures 2-7)] The head impact absorption sheet A1 is an impact-absorbing structure that uses spherical cushioning material to protect the human body at the top of the head and mitigates external forces applied to the top of the head through its single-layer structure. As shown in Figures 2 and 3, the head impact absorption sheet A1 comprises multiple polystyrene foam spheres 10 (spherical cushioning material) and multiple mesh fabrics 20 (fabric).

[0018] The expanded polystyrene sphere 10 is a cushioning material with a diameter that achieves the target shock absorption performance through a single-layer structure composed of 37 planar aggregates. The safety standard for the target shock absorption performance of the expanded polystyrene sphere 10 is determined by the JCF safety standard, and then a spherical cushioning material with a diameter that satisfies the established JCF safety standard is selected. Here, "JCF" is an abbreviation for "Japan Cycling Federation," representing the "Japan Cycling Federation." In Example 1, a 30mm diameter expanded polystyrene sphere 10, shown in Figure 4, was selected as a spherical cushioning material that satisfies the JCF safety standard through a single-layer structure. The reasons for this selection are explained below.

[0019] When selecting spherical cushioning material with a diameter that satisfies the JCF safety standards, if the material is decided to be expanded polystyrene, a preliminary impact test or rudimentary impact test is performed using a cushioning material aggregate sample made by preparing expanded polystyrene spheres of various diameters and arranging them in a single layer structure. As shown in Figure 5, the test conditions for the rudimentary impact test are as follows: a head impactor 100 having rigidity equivalent to that of a human head is dropped from a height of 1.5 m (JCF safety standard) towards a cushioning material aggregate sample 200 (see Figure 6) arranged in a square shape with 5 x 5 (= 25 spheres per layer). The cushioning material aggregate sample 200 is made from the expanded polystyrene spheres of various diameters that have been prepared. When a rudimentary impact test was performed using an expanded polystyrene sphere with a diameter of 30 mm, as shown in Figure 7, the triaxial composite acceleration (G) was approximately 200 G, which was confirmed to be below the specified JCF safety standard of 300 G. Therefore, in Example 1, a 30mm diameter polystyrene foam sphere 10 was selected as the spherical cushioning material for the head impact absorbing sheet A1.

[0020] The mesh fabric 20 is constructed by preparing two pieces of fabric that have enough width and breathability to enclose the head protection area 30 (protection area) of the human body made of polystyrene foam spheres 10, and overlapping the two pieces of fabric. Preferably, the mesh fabric 20 is made of a stretchable polyester fabric or the like with a mesh of coarseness that allows the polystyrene foam spheres 10, which are stored and placed in the storage space 40 described later, to be visible through it. The mesh fabric 20 has a mesh with a coarseness in units of mesh, for example, ranging from a few meshes that hold the polystyrene foam spheres 10 to about 10-something meshes that ensure breathability, within a 1-inch length range.

[0021] As shown in Figure 2, the mesh fabric 20 has a storage line joint 21 formed by sewing two pieces of fabric together in a linear fashion, and an outer perimeter line joint 22. The storage line joint 21 is joined by sewing together in a linear fashion at equal intervals with a width of approximately half the circumference of the polystyrene foam sphere 10. That is, adjacent storage line joints 21 have a width of approximately half the circumference of the sphere, forming a storage space 40 for storing the polystyrene foam sphere 10, as shown in Figure 3. The outer perimeter line joint 22 is joined by sewing together in a linear fashion around the outer perimeter of the outermost polystyrene foam sphere 10 when it is filled with 37 polystyrene foam spheres 10 necessary to cover the top of the head protection area 30. Here, the shape of the outer perimeter line joint 22 is a hexagon that corresponds to the shape of the top of the head, as shown in Figure 2. Furthermore, the left and right sides of the hexagon have storage line joints 21 that also serve as outer perimeter line joints 22.

[0022] As shown in Figure 2, the polystyrene foam spheres 10 are stored in each of the seven rows of storage spaces 40 formed by the storage line joints 21 and outer circumference line joints 22 of the overlapping mesh fabric 20, without creating any gaps between them in the row direction. Then, as shown in Figures 2 and 3, the polystyrene foam spheres 10 in adjacent rows are placed at positions shifted by a radius from each other, so that they are arranged alternately with an approximate radius offset. As shown in Figure 2, a gap is formed between two adjacent rows of polystyrene foam spheres 10 due to the alternating arrangement of the polystyrene foam spheres 10, resulting in a meandering shape.

[0023] [Manufacturing method for the head impact absorbing sheet (Figures 8-11)] The manufacturing method for the head impact absorbing sheet A1 includes, as shown in the step-by-step flow in Figure 8, a spherical cushioning material selection procedure S1, a protective area setting procedure S2, a fabric overlapping procedure S3, a storage space formation procedure S4, a spherical cushioning material insertion procedure S5, and a finishing procedure S6. The details of the spherical cushioning material selection procedure S1 to the finishing procedure S6 are described below.

[0024] (Spherical cushioning material selection procedure S1) The spherical cushioning material selection procedure S1 involves selecting a spherical cushioning material having a diameter that satisfies the JCF safety standards with a single-layer structure. In Example 1, as described above, a polystyrene foam sphere 10 with a diameter of 30 mm was selected as the spherical cushioning material.

[0025] (Protective area setting procedure S2) The protection area setting procedure S2 defines the protection area of ​​the human body to be protected by the polystyrene foam sphere 10. In the protection area setting procedure S2 of Example 1, the protection area of ​​the polystyrene foam sphere 10 is defined as the head protection area, with the aim of reducing the damage to the top of the head in the event of a fall. When the head protection area is replaced with the prepared mesh fabric 20 and the area is transformed, it becomes the hexagonal head protection area 30 shown in Figures 9 and 10. After defining the head protection area 30 in the protection area setting procedure S2, the head impact absorbing sheet A1 is manufactured by going through the procedure described below.

[0026] (Fabric layering procedure S3) The fabric layering procedure S3 involves preparing two pieces of mesh fabric 20 that have the size, breathability, and elasticity to encompass the set head protection area 30, and layering them on top of each other.

[0027] (Storage space formation procedure S4: Figure 9) The storage space formation procedure S4 forms multiple rows of storage spaces 40 for storing multiple polystyrene foam spheres 10. As shown in Figure 9, the storage spaces 40 are formed by sewing together two overlapping mesh fabrics 20 with equally spaced storage lines (storage line joints 21) that have a width W approximately half the circumference of the 30 mm diameter polystyrene foam sphere 10. Therefore, as shown in Figure 9, when the two overlapping mesh fabrics 20 between adjacent storage line joints 21 are pushed open to form a circle, the storage space 40 corresponds to the outer shape of the polystyrene foam sphere 10 and becomes a space into which the polystyrene foam sphere 10 can be inserted. Here, the width W of adjacent storage line joints 21 may be equal to half the circumference of the polystyrene foam sphere 10 or slightly shorter than half, depending on the elasticity of the mesh fabric 20. Furthermore, the width W of the adjacent storage line joint 21 needs to be slightly longer than half the circumference of the polystyrene foam sphere 10 in order to ensure smooth insertion of the polystyrene foam sphere 10 when the mesh fabric 20 is not elastic. Therefore, the expression "width W is approximately half the circumference of the polystyrene foam sphere 10" implies that a width slightly before or after half the circumference is acceptable.

[0028] (Spherical cushioning material insertion procedure S5: Figure 10) The spherical cushioning material insertion procedure S5 involves inserting the selected polystyrene foam spheres 10 into each of the multiple rows of storage spaces 40, and at that time, the polystyrene foam spheres 10 in adjacent rows are arranged alternately at shift positions moved by approximately the radius of the sphere, as shown in Figure 10. In the spherical cushioning material insertion procedure S5, as shown in Figure 10, when inserting the selected polystyrene foam spheres 10 into each of the multiple rows of storage spaces 40, multiple polystyrene foam spheres 10 are inserted without any gaps between them. Here, when arranging the polystyrene foam spheres 10 in adjacent rows alternately at shift positions moved by the radius of the sphere, it is difficult to place them precisely at positions shifted by the radius of the sphere due to the degree of shrinkage of the mesh fabric 20 and the precision of the sewing. Therefore, the shift position of the polystyrene foam spheres 10 in adjacent rows is expressed as "arrangement of spherical cushioning materials shifted by approximately the radius and arranged alternately," which includes the meaning that a shift width of the radius is allowed.

[0029] (Finishing procedure S6: Figure 11) In finishing step S6, as shown in Figure 11, the polystyrene foam spheres 10 are inserted until the crown protection area 30 is covered, and then the outermost polystyrene foam spheres 10 are sutured together along the outer circumference line (outer circumference line joint 22). In finishing step S6, any excess mesh fabric 20 left over from sewn along the outer circumference line is cut and removed along the cut line 50 to produce the crown impact absorbing sheet A1.

[0030] [Background Technology Issues and Solutions (Figures 12-15)] Currently, there are two main types of head protection for bicycles and electric scooters (small designated mopeds). One is a hard-type head protection that directly covers the head area with a single-piece molded cushioning material, commonly known as a helmet. The other is a soft-type head protection that softly covers the head area with an impact-absorbing structure made of relatively small, softly bonded cushioning material, commonly known as a protective cap. Regarding soft-type head protection, a laminated type with two or three layers of impact-absorbing structure is known as a protective device and manufacturing method for high-energy collision accidents, such as those involving the fall of two-wheeled vehicles.

[0031] Hard-type (one-piece molded) head protection is generally developed with high-energy collisions involving cyclists in mind, and is sold in compliance with safety standards such as those of the JCF (see Japanese Patent Publication No. 2008-163500, etc.). However, as shown in Figure 12, hard-type (one-piece molded) head protection has the characteristic of being highly productive due to its one-piece molding process, but lacks flexibility and portability. For this reason, the poor fit and portability of hard-type (one-piece molded) head protection are major factors hindering its widespread adoption.

[0032] Hard-type (foldable) head protection devices were developed to improve upon the poor storage capabilities of hard-type (one-piece molded) head protection devices. They maintain high impact absorption while adding a folding mechanism (see Japanese Patent Publication No. 2009-519381, etc.). However, as shown in Figure 13, hard-type (foldable) head protection devices are heavy, weighing approximately 400g, posing a significant challenge in terms of lightweight design, and they also suffer from the lack of flexibility inherent in hard-type devices.

[0033] On the other hand, soft-type (single-layer) head protection has the advantage of being more flexible and comfortable to wear than hard-type head protection (see Patent Document 1). However, in order to make soft-type (single-layer) head protection have the same high level of head protection performance and breathability as hard-type head protection while taking advantage of its flexibility, it is necessary to make it a laminated type with two or three layers of impact-absorbing structure (see Patent Document 2).

[0034] In soft-type (layered) head protection devices, the mass of the hollow polyethylene beads (hard) used as cushioning material increases significantly when the impact-absorbing structure is made into a two- or three-layer structure. For example, the current product has a single-layer structure of hollow polyethylene beads with a mass of 75g. If this 75g single-layer current product is reused, it will become 150g for a two-layer structure and 225g for a three-layer structure. Therefore, as shown in Figure 14, head protection devices that apply a three-layer impact-absorbing structure have the problem of reduced lightness of the head protection device and a significant increase in the number of cushioning material components, leading to a decrease in productivity. Furthermore, the number of hollow polyethylene beads used as cushioning material is 396 for a single-layer structure, 792 for a two-layer structure, and 1,188 for a three-layer structure. In addition, when using the soft bonding method for cushioning material described in Patent Document 2, there is a problem that the entire impact-absorbing structure will not bend and its flexibility cannot be maintained unless small-diameter spherical cushioning materials are arranged with a certain amount of spacing between them. In addition, there are concerns that the impact-absorbing structures of soft-type (laminated) head protection devices may lead to decreased productivity and reduced impact absorption due to the need to arrange the cushioning material at certain intervals.

[0035] In response to the above background technology, the inventors considered whether it would be possible to solve the problems of reduced productivity, lightness, and conformability of deformation that occur when ensuring impact absorption by a laminated structure, while retaining the advantages of applying it to soft-type head protection (high flexibility and comfortable fit). As a result of considering solutions to these problems, the inventors focused on the fact that by making the spherical cushioning material a single-layer structure, making the fabric that houses the spherical cushioning material a cushioning material connecting structure, and devising the arrangement of the spherical cushioning material, it is possible to gather multiple spherical cushioning materials in a planar area while keeping the surface rigidity of the gathering area low.

[0036] The head impact absorbing sheet A1 and its manufacturing method select multiple polystyrene foam spheres 10, each with a diameter of 30 mm, to satisfy the target JCF safety standards as spherical cushioning material, in accordance with this focus. The multiple polystyrene foam spheres 10 are then stored in each of the multiple rows of storage spaces 40 formed by the storage line joints 21 and outer circumference line joints 22 of the two mesh fabrics 20. Furthermore, the polystyrene foam spheres 10 are arranged in alternating positions, with adjacent rows of polystyrene foam spheres 10 shifted by approximately the radius. As a result, the head impact absorbing sheet A1 and its manufacturing method can achieve the required performance characteristics of impact absorption, productivity, lightness, and conforming deformation at a high level with a single-layer structure. Furthermore, as shown in Figure 15, head protection devices incorporating this top-of-the-head impact-absorbing sheet A1 have the characteristic of achieving high levels of performance requirements such as safety (impact absorption), comfort (flexibility, breathability, lightweight), portability, and productivity.

[0037] [Effect of the head impact absorbing sheet (Figures 16-19)] The effects of the head-top impact-absorbing sheet A1 are described below, divided into "impact absorption," "productivity improvement: significant reduction in the number of parts," "productivity improvement: no need for placement at regular intervals," "lightweighting," "improved conformability and deformation," and "improved breathability."

[0038] (Shock absorption mechanism: Figures 16 and 17) The impact absorption function of the head impact absorption sheet A1 is achieved by selecting polystyrene foam spheres 10 with a diameter that satisfies safety standards, and arranging multiple selected polystyrene foam spheres 10 in a covered manner within a designated protective area.

[0039] For the comparative impact absorption performance test, two types of cushioning material aggregate samples were prepared: 200' (Figure 16) consisting of 7 x 7 (= 2 layers) hollow polyethylene beads used in soft-type (laminated) head protection devices, and 200'' (Figure 16) consisting of 7 x 7 (= 3 layers) hollow polyethylene beads. This comparative test was conducted using three types of cushioning material aggregate samples: 1-layer cushioning material aggregate sample 200 (Figure 6: polystyrene sphere 10), 2-layer cushioning material aggregate sample 200' (hollow polyethylene beads), and 3-layer cushioning material aggregate sample 200'' (hollow polyethylene beads). The test conditions were the same as those for a hypothetical impact test in which a head impactor 100 was free-dropped from a height of 1.5 m, as shown in Figure 5.

[0040] This comparative test showed that, in the case of a single-layer cushioning material sample 200 made of expanded polystyrene spheres 10, the triaxial composite acceleration (G) was approximately 200G, as shown in Figure 17(1), which is below the JCF safety standard of 300G. In the case of a two-layer cushioning material sample 200' made of hollow polyethylene beads, the triaxial composite acceleration (G) was slightly over 300G, as shown in Figure 17(2), which is above the JCF safety standard of 300G. In the case of a three-layer cushioning material sample 200'' made of hollow polyethylene beads, the triaxial composite acceleration (G) was approximately 170G, as shown in Figure 17(3), which is below the JCF safety standard of 300G.

[0041] Therefore, the impact absorption performance of the single-layer cushioning material aggregate sample 200 made of expanded polystyrene spheres 10 in Example 1 is at the same level as the impact absorption performance of the three-layer cushioning material aggregate sample 200 made of hollow polyethylene beads. Furthermore, it was confirmed that the impact absorption performance in both cases was below the JCF safety standard of 300G.

[0042] As described above, the inventive technology shown in Figure 18 (single-layer head impact-absorbing sheet A1) can be said to have the same level of impact absorption as a three-layer impact-absorbing structure made of hollow polyethylene beads. For this reason, the comparative technology is an impact-absorbing structure shown in Figure 19, in which 146 hollow polyethylene beads (cushioning material) with a diameter of 12 mm are placed with gaps between them in the area of ​​the outer peripheral line joint portion 22 of each layer, and these are stacked in three layers, and the following functions will be explained.

[0043] (Productivity improvement effect: significant reduction in the number of parts) The productivity improvement effect of the invented technology, the head-top impact-absorbing sheet A1 (Figure 18), is achieved by significantly reducing the number of cushioning material components compared to the comparative technology's impact-absorbing structure (Figure 19).

[0044] In other words, the comparative technology is an impact-absorbing structure made of multiple hollow polyethylene beads with a diameter of 12 mm, and to have the same impact-absorbing performance as the inventive technology, three layers are required, resulting in the use of 438 hollow polyethylene beads (146 beads x 3 layers). In contrast, the inventive technology is a structure made of a single layer of 30 mm diameter polystyrene foam spheres 10. Therefore, the number of polystyrene foam spheres 10 is reduced to 37 (37 spheres x 1 layer). In short, by using large diameter (30 mm) polystyrene foam spheres 10 with high impact absorption, it is possible to significantly reduce the number of parts by approximately 1 / 12. Thus, the head impact-absorbing sheet A1 of the inventive technology (Figure 18) is significantly more productive than using the impact-absorbing structure of the comparative technology (Figure 19).

[0045] (Productivity improvement effect: No need to place items at regular intervals) The productivity improvement effect of the invented technology's head-top impact-absorbing sheet A1 (Figure 18) is achieved by eliminating the need to arrange cushioning material at regular intervals, compared to the impact-absorbing structure of the comparative technology (Figure 19).

[0046] In other words, the impact-absorbing structure of the comparative technology arranges hollow polyethylene beads (cushioning material) at regular intervals from each other, as shown in Figure 19, in order to ensure conforming deformation. Furthermore, if the soft bonding method for cushioning material proposed in Example 1 of Patent Document 1 is used, advanced sewing techniques are required to accurately pass synthetic resin threads through the center of small spherical cushioning material, and the work of passing synthetic resin threads through a large number of small cushioning material is time-consuming. In contrast, the head impact-absorbing sheet A1 of the inventive technology achieves conforming deformation by arranging the polystyrene foam spheres 10 in adjacent rows in alternating positions shifted by a radius, as will be described later. Therefore, when inserting the polystyrene foam spheres 10 into the storage spaces 40 of multiple rows formed by adjacent storage line joints 21, the polystyrene foam spheres 10 can be inserted without gaps, and there is no need to arrange them at regular intervals. Therefore, the head impact-absorbing sheet A1 of the inventive technology is significantly more productive than using the impact-absorbing structure of the comparative technology (Figure 19).

[0047] (Lightweighting effect) The weight reduction effect of the invented technology's top-of-the-head impact-absorbing sheet A1 (Figure 18) is achieved by significantly reducing the number of cushioning material components compared to the comparative technology's impact-absorbing structure (Figure 19).

[0048] In other words, the impact-absorbing structure of the comparative technology has a total cushioning material mass of approximately 80g (146 beads × 3 layers × 0.182g). Note that "0.182g" is the mass of one hollow polyethylene bead. In contrast, the head-top impact-absorbing sheet A1 of the inventive technology has a total mass of approximately 25g (37 polystyrene spheres × 1 layer × 0.689g). Note that "0.689g" is the mass of one polystyrene sphere 10. In other words, the total mass of the cushioning material is reduced to less than 1 / 3 of the impact-absorbing structure of the comparative technology (Figure 19). Therefore, the inventive technology can be made lighter by using the head-top impact-absorbing sheet A1 (Figure 18) than by using the impact-absorbing structure of the comparative technology (Figure 19).

[0049] (Improved conformability and deformation) The improved conformability of the head impact absorbing sheet A1 (Figure 18) of the inventive technology is achieved by shifting the adjacent cushioning material by a radius relative to the impact absorbing structure of the comparative technology (Figure 19).

[0050] In other words, as shown in Figure 19, the impact-absorbing structure of the comparative technology has multiple rows of linear hollow polyethylene beads when viewed vertically, and multiple rows of linear hollow polyethylene beads when viewed horizontally. Therefore, unless a certain amount of space is provided between the hollow polyethylene beads, the surface shape will only deform around one axis, either vertical or horizontal, resulting in poor shape conformity to the overall rounded shape of the head. In particular, the soft bonding method for the cushioning material proposed in Example 1 of Patent Document 1 has the four corners of adjacent small cushioning materials bonded with synthetic resin threads, so the surface rigidity is high even if the surface shape deforms only slightly around one axis. In contrast, as shown in Figure 18, the head top impact-absorbing sheet A1 of the inventive technology has adjacent polystyrene foam spheres 10 shifted by approximately the radius of the sphere and arranged alternately. Therefore, the surface rigidity is reduced because it can bend in all directions, making it easier to conform to the overall rounded shape of the head. Therefore, the head impact absorbing sheet A1 of the inventive technology (Figure 18) exhibits improved conforming deformation performance compared to the impact absorbing structure of the comparative technology (Figure 19). The conforming deformation performance of the head impact absorbing sheet A1 can be further improved by using a stretchable mesh fabric 20.

[0051] (Improves breathability) The improved breathability of the inventive head-top impact-absorbing sheet A1 (Figure 18) is achieved by selecting a mesh fabric 20 with a mesh size that allows the cushioning material to be seen through, compared to the impact-absorbing structure of the comparative technology (Figure 19).

[0052] In other words, the impact-absorbing structure of the comparative technology, as disclosed in Patent Document 2, adheres hollow polyethylene beads between fine, low-breathability mesh fabrics in order to ensure bonding strength with the mesh fabric. Therefore, there is room for improvement in the breathability of the overall structure of the impact-absorbing structure of the soft-type (laminated) head protection device. In contrast, the head top impact-absorbing sheet A1 of the inventive technology has a structure in which it is placed between two layers of mesh fabric 20 with a mesh size that allows the expanded polystyrene spheres 10 stored in the storage space 40 to be seen through. Therefore, it is possible to use a coarser mesh than the impact-absorbing structure of the comparative technology. Thus, the head top impact-absorbing sheet A1 of the inventive technology (Figure 18) can improve breathability compared to using the impact-absorbing structure of the comparative technology (Figure 19).

[0053] [Effects of the head impact absorbing sheet A1 and its manufacturing method] (1) The shock-absorbing structure that mitigates external forces comprises a plurality of spherical cushioning materials (expanded polystyrene spheres 10) whose single-layer structure provides the target shock absorption performance, and a plurality of overlapping fabrics (mesh fabrics 20) that have an area large enough to enclose the human body protection area (top of head protection area 30) provided by the spherical cushioning materials. The fabrics have storage line joints 21 that are joined linearly at equal intervals with a width of approximately half the circumference of the selected spherical cushioning materials, and outer perimeter line joints 22 that are joined linearly around the outer perimeter of the outermost spherical cushioning material when the plurality of spherical cushioning materials covering the protection area are stored inside. The spherical cushioning materials are stored in each of the plurality of rows of storage spaces 40 formed by the storage line joints 21 and outer perimeter line joints 22 of the overlapping fabrics, and the spherical cushioning materials in adjacent rows are arranged alternately with an offset of approximately the radius. This invention provides a single-layer shock-absorbing structure (headrest shock-absorbing sheet A1) that achieves high levels of performance requirements such as shock absorption, productivity, lightness, and conforming deformation.

[0054] (2) A preliminary impact test or a simulated impact test is performed using a sample of cushioning material arranged in a single layer to select a cushioning material with a shape and material that satisfies the target impact absorption performance safety standard (JCF safety standard) based on the test results. This invention can satisfy the target impact absorption performance safety standard while being an impact absorption structure (head impact absorption sheet A1) with a single layer structure.

[0055] (3) The fabric is stored in the storage space 40. spherical cushioning material A mesh fabric 20 is selected that has a coarseness that allows the (styrofoam sphere 10) to be seen through, and is also stretchable. This invention can reduce the surface rigidity of the impact-absorbing structure (head impact-absorbing sheet A1) to improve its conformability to deformation, and can also improve the breathability of the impact-absorbing structure compared to when a fine mesh fabric is used.

[0056] (4) The impact-absorbing structure is an impact-absorbing sheet that is incorporated into the hat body C1 to C4 made of a flexible material to form head protection equipment B1 to B4'. This invention can provide an impact-absorbing sheet that can be applied to head protection equipment B1 to B4' that achieves a high level of safety, comfort (flexibility, breathability, lightness), storage, and productivity.

[0057] (5) The impact-absorbing sheet is a top-of-the-head impact-absorbing sheet A1 which has a spherical cushioning material (expanded polystyrene sphere 10) as the protective area for the human body at the top of the head, and a polygonal outer peripheral line joint portion 22 that corresponds to the shape of the top of the head. This invention can provide a top-of-the-head impact-absorbing sheet A1 which can be applied to head protection devices B1 to B4' that mitigate the force received at the top of the head.

[0058] (6) A method for manufacturing an impact-absorbing structure that mitigates external forces comprises a spherical cushioning material selection procedure S1, a protective area setting procedure S2, a fabric overlapping procedure S3, a storage space formation procedure S4, a spherical cushioning material insertion procedure S5, and a finishing procedure S6. The spherical cushioning material selection procedure S1 involves selecting a spherical cushioning material (expanded polystyrene sphere 10) that can achieve the target impact absorption performance with a single-layer structure. The protective area setting procedure S2 involves defining a protective area for the human body (head protection area 30) using the spherical cushioning material. The fabric overlapping procedure S3 involves preparing and overlapping multiple mesh fabrics 20 that have sufficient width and breathability to enclose the protective area. The storage space formation procedure S4 involves joining the overlapped mesh fabrics 20 with equally spaced storage lines that are approximately half the circumference of the selected spherical cushioning material to form multiple rows of storage spaces 40 for the spherical cushioning material. The spherical cushioning material insertion procedure S5 involves inserting selected spherical cushioning materials into each of the multiple rows of storage spaces 40, arranging them alternately with the spherical cushioning materials in adjacent rows offset by approximately the radius. In the finishing procedure S6, once the spherical cushioning materials are inserted until the protective area is covered, they are joined by the outer peripheral line surrounding the outermost spherical cushioning material, and the unnecessary mesh fabric 20 is removed along the cut line 50. This invention provides a method for manufacturing a single-layer shock-absorbing structure (head impact-absorbing sheet A1) that achieves the required performance of shock absorption, productivity, lightness, and conforming deformation at a high level. [Examples]

[0059] Example 2 is an example of a head-side impact absorbing sheet A2 (an example of an impact absorbing structure) with the head-side area as the protective area for the human body, and a method for manufacturing the head-side impact absorbing sheet A2.

[0060] [Configuration of the head-side impact absorbing sheet] The head-side impact-absorbing sheet A2 is an impact-absorbing structure that uses spherical cushioning material to protect the head-side area of ​​the human body and mitigates external forces received on the head-side area through its single-layer structure. As shown in Figure 20, the head-side impact-absorbing sheet A2 comprises 45 polystyrene foam spheres 10 and two mesh fabrics 20. The polystyrene foam spheres 10 have a diameter of 30 mm, as in Example 1. The mesh fabrics 20 have the area to enclose the head-side protection area of ​​the human body provided by the polystyrene foam spheres 10 and are breathable, and the material is a coarse mesh material, as in Example 1.

[0061] As shown in Figure 20, the mesh fabric 20 has a storage line joint 21 and an outer perimeter line joint 22, which are formed by sewing together two layers of fabric. The storage line joint 21 is joined by sewing together lines at equal intervals with a width of approximately half the circumference of the polystyrene foam spheres 10 selected as spherical cushioning material. The outer perimeter line joint 22 is joined by sewing together lines around the outer perimeter of the outermost polystyrene foam sphere 10 when 45 polystyrene foam spheres 10 covering the head side protection area are stored inside. Here, as shown in Figure 20, the shape of the outer perimeter line joint 22 is a rectangle that wraps around the shape of the head side. Note that the storage line joint 21 also serves as the outer perimeter line joint 22 on opposite long sides of the rectangle.

[0062] As shown in Figure 20, the polystyrene foam spheres 10 are stored in each of the three rows of storage spaces 40 formed by the storage line joints 21 and outer circumference line joints 22 of the overlapping mesh fabric 20, without creating any gaps between them in the row direction. The polystyrene foam spheres 10 in adjacent rows are then arranged alternately with a radial shift, as shown in Figure 20.

[0063] Figures 21(a) and (b) show an external view of the head-side impact-absorbing sheet A2 of Example 2 when attached to the head. Figure 22 shows an external view of the head protection device B5 with the head-side impact-absorbing sheet A2 of Example 2 embedded in the finishing fabric. Here, Figure 20 shows an example in which the expanded polystyrene spheres 10 are stored in three rows, while Figures 21 and 22 show an example in which the expanded polystyrene spheres 10 are stored in two rows. The manufacturing method of the head-side impact-absorbing sheet A2 is the same as that of the top-of-the-head impact-absorbing sheet A1 of Example 1, and the function is also the same, so the explanation is omitted.

[0064] [Effects of the head-side impact-absorbing sheet A2] (7) The impact-absorbing sheet A2 is a head-side impact-absorbing sheet A2 which has a head-side area protected by a spherical cushioning material (expanded polystyrene sphere 10) on the head side, and a rectangular outer peripheral line joint 22 that conforms to the shape of the head side when wrapped around it. This invention can provide a head-side impact-absorbing sheet A2 that can be applied to head protection equipment B5 and the like, which reduces the force received on the head side and achieves high levels of safety, comfort (flexibility, breathability, lightness), storage, and productivity. [Examples]

[0065] Example 3 is an example of a head-wide impact absorbing sheet A3 (an example of an impact absorbing structure) and a method for manufacturing the head-wide impact absorbing sheet A3, with the entire head as the protected area of ​​the human body.

[0066] [Configuration of the full-head impact absorption sheet] The whole-head impact absorption sheet A3 is an impact-absorbing structure that uses spherical cushioning material to protect the entire head and mitigates external forces on the entire head through its single-layer structure. The whole-head impact absorption sheet A3 is a combination type, and as shown in Figures 23(a) and (b), it is constructed by combining the top-of-the-head impact absorption sheet A1 of Example 1 and the side-of-the-head impact absorption sheet A2 of Example 2 by joining them together with sutures 60 and the like.

[0067] Examples of applying the A3 full-head impact absorption sheet to head protection include the bandana-style head protection B6 shown in Figure 24(a), the fleece-hat-style head protection B7 shown in Figure 24(b), and the knit-hat-style head protection B8 shown in Figure 24(c). The manufacturing method for the entire head impact absorbing sheet A3 is simply the same as that of the manufacturing methods for the top head impact absorbing sheet A1 and the side head impact absorbing sheet A2 in Example 1, with the addition of a combination and connection procedure. Therefore, the function is the same as in Example 1, and thus the explanation is omitted.

[0068] [Effects of the A3 full-head impact absorption sheet] (8) The impact-absorbing sheet is a head-whole-head impact-absorbing sheet A3 that combines a head-top impact-absorbing sheet A1 having a hexagonal outer peripheral line joint 22 that conforms to the shape of the top of the head, with the entire head being protected by a spherical cushioning material (expanded polystyrene sphere 10), and a head-side impact-absorbing sheet A2 having a rectangular outer peripheral line joint 22 that conforms to the shape of the side of the head in a wrapped state. This invention provides a combined head-whole-head impact-absorbing sheet A3 that can be applied to head protection devices B6~B8 etc., which mitigates the force received on the entire head and achieves high levels of safety, comfort (flexibility, breathability, lightness), storage, and productivity. [Examples]

[0069] Example 4 is an example of a head-to-head impact absorbing sheet A4 (an example of an impact absorbing structure) with a folded structure, where the entire head is the protected area of ​​the human body, and is a method for manufacturing the head-to-head impact absorbing sheet A4.

[0070] [Configuration of the full-head impact absorption sheet] The A4 whole-head impact absorbing sheet is an impact absorbing structure that uses spherical cushioning material to protect the entire head and mitigates external forces on the entire head through its single-layer structure. The following A4-1 and A4-2 whole-head impact absorbing sheets are integrated impact absorbing sheets that are manufactured as a single unit, rather than being a combined structure as in Example 3.

[0071] As shown in Figure 25, the head-whole impact absorbing sheet A4-1 has an outer perimeter line joint 22, a cut line 50, and a valley fold joint 70. The outer perimeter line joint 22 is an expanded shape that extends in four equiangular directions from the central hexagonal region shown in Example 1 to correspond to the overall shape of the head. The cut line 50 is a hexagonal shape that encloses the expanded region of the outer perimeter line joint 22 that extends in four equiangular directions. The valley fold joint 70 is a part where the mesh fabric 20 remaining at the four corners of the outer perimeter region due to the difference in area between the cut line 50 and the outer perimeter line joint 22 is valley-folded along the radial central fold line L, and then folded and joined by sewing or the like. The head-whole impact absorbing sheet A4-1 of Example 4 is shown in Figure 26(a) in the product state with the valley fold joint 70 joined, and the appearance view of the image of it being worn on the entire head is shown in Figure 26(b).

[0072] As shown in Figure 27, the head-whole impact absorbing sheet A4-2 has an outer perimeter line joint 22, a cut line 50, and a valley fold joint 70. The outer perimeter line joint 22 is a cross-shaped unfolded area, consisting of a rectangular area extending laterally from the top of the head toward the left and right ears, and an extended area extending in the front-to-back direction from the center of the rectangular area toward the forehead and the back of the head. The cut line 50 is a square shape that encloses the unfolded shape of the cross-shaped area of ​​the outer perimeter line joint 22. The valley fold joint 70 is a part where the mesh fabric 20 remaining at the four corners of the outer perimeter area due to the difference in area between the cut line 50 and the outer perimeter line joint 22 is valley-folded along the radial central fold line L, then folded and joined by sewing or other means. Figure 28(a) shows the product state of the head-whole impact absorbing sheet A4-2 of Example 4 with the valley fold joint 70 joined, and Figure 28(b) shows an external view of the image of it being worn on the entire head. The manufacturing method for the head-whole impact-absorbing sheets A4-1 and A4-2 is the same as that for the head-top impact-absorbing sheet A1 in Example 1, and the function is also the same as in Example 1, so the explanation is omitted.

[0073] [Effects of the A4 full-head impact absorption sheet] (9) The impact-absorbing sheet is a full-head impact-absorbing sheet A4 in which the protective area of ​​the human body using spherical cushioning material (expanded polystyrene sphere 10) covers the entire head. The full-head impact-absorbing sheet A4 has an outer peripheral line joint portion 22 formed by unfolding the three-dimensional shape of the entire head into a planar shape, a polygonal cut line 50 that encloses the unfolded shape of the outer peripheral line joint portion 22, and a valley fold joint portion 70 formed by folding and joining the remaining fabric portion when the outer peripheral line joint portion 22 is removed from the cut line 50. This invention can provide an integrated full-head impact-absorbing sheet A4 that can be applied to head protection equipment B that reduces the force received on the entire head and achieves high levels of safety, comfort (flexibility, breathability, lightness), storage, and productivity.

[0074] The impact-absorbing structures and methods for manufacturing impact-absorbing structures of Examples 1 to 4 have been described above with reference to the drawings. However, the specific configuration of the impact-absorbing structures and methods for manufacturing impact-absorbing structures of the present invention is not limited to Examples 1 to 4, and changes or additions to the design are permitted as long as they do not depart from the gist of the invention as described in each claim of the patent.

[0075] Examples 1-4 show an example of a spherical cushioning material using a solid polystyrene foam sphere 10 with a diameter of 30 mm. However, the spherical cushioning material is not limited to the configuration examples shown in Examples 1-4. For example, the material of the spherical cushioning material can be any material with shock-absorbing properties other than polystyrene foam, such as foamed propylene, foamed synthetic rubber, sponge, or composite material. Also, the shape of the spherical cushioning material can be a hollow sphere, a perforated hollow sphere like polyethylene beads, or other shapes besides a solid sphere. In addition, the spherical cushioning material is not limited to a spherical shape with curved surfaces all around, but can also be a spherical shape made of a polyhedron, such as a regular dodecahedron, where a sphere is formed by combining many planes. Furthermore, the diameter of the spherical cushioning material can be larger or smaller than 30 mm. For example, if the material of the spherical cushioning material is the same, the diameter is determined according to the target shock absorption performance. If the target shock absorption performance is the same, the diameter is determined according to the shock absorption performance of the material.

[0076] Examples 1 to 4 show examples in which a polyester mesh fabric 20 with a mesh size that allows the polystyrene sphere 10 to be seen through and which has high elasticity is selected as the fabric. However, the fabric is not limited to the mesh fabric 20. For example, the fabric may be a mesh fabric with a higher or lower degree of breathability than the mesh fabric 20. Also, the fabric material may be a material other than polyester, and a material with a higher or lower degree of elasticity than the mesh fabric 20 may be selected.

[0077] Examples 1 to 4 show an example in which the storage line joint 21 and the outer perimeter line joint 22 are joined by sewing together two mesh fabrics 20 while they are overlapping. However, the storage line joint and the outer perimeter line joint are not limited to joints made by sewing together two mesh fabrics. The storage line joint and the outer perimeter line joint may be joined by adhesive bonding using an adhesive, for example, or by heat welding by applying heat in a linear manner to fuse them together. Furthermore, the width of the joint of the storage line joint and the outer perimeter line joint may be set to various dimensions depending on the required joint strength. Moreover, the linear shape of the storage line joint and the outer perimeter line joint is not limited to a straight line, but may also be an arc curve or a spiral curve.

[0078] Example 1 shows an example where the top of the head impact absorbing sheet A1 has a hexagonal outer perimeter line joint 22 that corresponds to the shape of the top of the head, in which the area for housing the polystyrene sphere 10 is located. However, the outer perimeter line joint 22 may be a polygon with heptagons or more, a perfect circle, or an ellipse, depending on the diameter of the spherical cushioning material and the setting of the protective area. Also, Example 1 shows an example of an internal type in which the top of the head impact absorbing sheet A1 is fixed to the inside of the hat body (head protectors B1 to B3 in Figure 1) and an external type in which the top of the head impact absorbing sheet A1 is fixed to the outside of the hat body (head protectors B4, B4' in Figure 1). However, as a head protector, for example, as shown in Figure 29, the top of the head impact absorbing sheet A1 may be used simply by placing it inside a larger hat body C6 without directly fixing the top of the head impact absorbing sheet A1 to the hat body.

[0079] Example 2 shows an example in which the head-side impact-absorbing sheet A2 has a rectangular outer perimeter line joint 22 that wraps around the shape of the head-side area and contains three rows of polystyrene foam spheres 10. However, the outer perimeter line joint 22 may be a rectangle that contains two rows of spherical cushioning material or four or more rows of spherical cushioning material, depending on the diameter of the spherical cushioning material and the width setting of the protective area.

[0080] Example 3 shows an example of a combination of a top-of-the-head impact-absorbing sheet A1 having a hexagonal outer peripheral line joint 22 and a side-of-the-head impact-absorbing sheet A2 having a rectangular outer peripheral line joint 22 that houses two rows of polystyrene foam spheres 10, as the overall head impact-absorbing sheet A3. However, the overall head impact-absorbing sheet A3 is not limited to the example described in Example 3. For example, the overall head impact-absorbing sheet may be an example of a combination of a top-of-the-head impact-absorbing sheet having a circular outer peripheral line joint and a side-of-the-head impact-absorbing sheet having a rectangular outer peripheral line joint that houses three or more rows of polystyrene foam spheres. Also, as shown in Figure 24, Example 3 shows examples of application to a bandana-style head protector B6, a fleece hat-style head protector B7, and a knit hat-style head protector B8. However, as shown in Figure 30, the overall head impact-absorbing sheet A3 may simply be used or provided to the user without concealing the overall head impact-absorbing sheet A3 with a chin strap 80, as shown in Figure 30.

[0081] Example 4 shows an example of a head-whole impact-absorbing sheet A4 having an outer perimeter line joint in the unfolded shape, a rectangular cut line, and valley fold joints formed by folding and joining the remaining fabric at the four corners. However, the outer perimeter line joint is not limited to a region radiating in four directions, as long as the unfolded shape is the unfolded shape of the entire head in a planar shape; it may also be a shape radiating in five or more directions. The cut line is not limited to a polygonal shape, as long as it encloses the unfolded shape of the outer perimeter line joint; it may also be a circular shape. The valley fold joint is not limited to an example where the remaining fabric at the four corners is folded and joined; if the unfolded shape radiates in three or fewer directions, or five or more directions, the remaining fabric may be used as a valley fold joint in a number corresponding to that shape.

[0082] Examples 1-4 illustrate the application of the impact-absorbing structure to soft-type head protection. However, the application of the impact-absorbing structure is not limited to the soft-type head protection shown in Examples 1-4. The impact-absorbing structure of the present invention can also be applied as an impact-absorbing sheet for hard-type helmets. Furthermore, the impact-absorbing structure of the present invention can also be applied as an impact-absorbing sheet for simple helmets with a low degree of hardness. In the example of application to soft-type head protection, the impact-absorbing structure is responsible for almost all of the target impact absorption performance. However, in the example of application to hard-type head protection, the target impact absorption performance is responsible for by both the helmet and the impact-absorbing structure. Therefore, the target impact absorption performance shared by the impact-absorbing structure is reduced by the amount of impact absorption performance shared by the helmet.

[0083] Examples 1 to 4 illustrate the application of the impact-absorbing structure to a head protector where the head is the protected area of ​​the human body. However, the application of the impact-absorbing structure is not limited to the head protector shown in Examples 1 to 4. The impact-absorbing structure of the present invention can also be applied as an impact-absorbing sheet to a lumbar protector, hip protector, knee protector, elbow protector, shoulder protector, etc., where the protected area of ​​the human body is a part other than the head, such as the waist, hip joint, knee, elbow, or shoulder. [Explanation of Symbols]

[0084] A1 Head top impact absorbing sheet (impact absorbing structure) 10. Styrofoam spheres (spherical cushioning material) 20 Mesh fabric (fabric) 21 Storage line joint 22 Outer perimeter line joint 30. Head top protection area (protection area) 40 storage spaces 50 cut lines

Claims

1. An impact-absorbing structure that mitigates external forces, Multiple spherical cushioning materials, which achieve the target shock absorption performance through a single-layer structure, It comprises multiple layers of fabric that overlap each other, having an area large enough to encompass the protective area of ​​the human body provided by the aforementioned spherical cushioning material, The fabric has storage line joints that are joined linearly at equal intervals with a width of approximately half the circumference of the selected spherical cushioning material, and outer circumference line joints that are joined linearly around the outer circumference of the outermost spherical cushioning material when multiple spherical cushioning materials covering the protective area are stored together. The spherical cushioning material is placed in each of the multiple rows of storage spaces formed by the storage line joints and outer peripheral line joints of the overlapping fabrics, and the spherical cushioning material in adjacent rows is arranged alternately with an offset of approximately the radius. The aforementioned spherical cushioning material undergoes a pre-impact test or simulated impact test in which a head impactor having the same rigidity as a human head is free-dropped from a height position according to the JCF safety standard toward a collection of cushioning materials arranged in a single layer. The cushioning material is selected based on a shape and material such that the test results using triaxial composite acceleration fall below the defined JCF safety standard. A shock-absorbing structure characterized by the following features.

2. In the impact absorbing structure described in claim 1, The aforementioned fabric is selected to be a mesh fabric with elasticity and a coarseness that allows the spherical cushioning material stored in the storage space to be seen through it. A shock-absorbing structure characterized by the following features.

3. In the impact absorbing structure described in Claim 1 or 2, The aforementioned impact-absorbing structure is an impact-absorbing sheet that is incorporated into a hat body made of a flexible material to serve as a head protector. A shock-absorbing structure characterized by the following features.

4. In the impact absorbing structure described in Claim 3, The aforementioned impact-absorbing sheet is a head-top impact-absorbing sheet in which the area of ​​the human body protected by the spherical cushioning material is the top of the head. The head impact absorbing sheet has a polygonal or circular shape at the outer peripheral line joint that corresponds to the shape of the head. A shock-absorbing structure characterized by the following features.

5. In the impact absorbing structure described in Claim 3, The aforementioned shock-absorbing sheet is a head-side shock-absorbing sheet in which the area of ​​the human body protected by the spherical cushioning material is the head side, The head-side impact-absorbing sheet has a rectangular shape at the outer peripheral line joint that corresponds to the shape of the head-side portion when wrapped around it. A shock-absorbing structure characterized by the following features.

6. In the impact absorbing structure described in Claim 3, The aforementioned impact-absorbing sheet is a head-whole impact-absorbing sheet in which the area of ​​the human body protected by the spherical cushioning material covers the entire head. The aforementioned head-whole impact-absorbing sheet has a combined structure comprising: a head-top impact-absorbing sheet with a polygonal or circular shape at the outer peripheral line joint that corresponds to the shape of the top of the head; and a head-side impact-absorbing sheet with a rectangular shape at the outer peripheral line joint that corresponds to the shape of the side of the head in a wrapped state. A shock-absorbing structure characterized by the following features.

7. In the impact absorbing structure described in Claim 3, The aforementioned impact-absorbing sheet is a head-whole impact-absorbing sheet in which the area of ​​the human body protected by the spherical cushioning material covers the entire head. The head-whole impact-absorbing sheet has an outer perimeter line joint formed by unfolding the three-dimensional shape of the entire head into a planar shape, a polygonal or circular cut line that encloses the unfolded shape of the outer perimeter line joint, and a valley fold joint formed by folding and joining the remaining fabric portion when the outer perimeter line joint is removed from the cut line. A shock-absorbing structure characterized by the following features.

8. A method for manufacturing an impact-absorbing structure that mitigates external forces, A procedure for selecting a spherical cushioning material that can achieve the target shock absorption performance through a single-layer structure, A procedure for setting a protective area to define the area of ​​human body protection provided by the aforementioned spherical cushioning material, A fabric layering procedure involves preparing multiple pieces of fabric having an area large enough to encompass the aforementioned protective area and layering them together, A storage space formation procedure comprising joining the overlapping fabrics with equally spaced storage lines having a width approximately half the circumference of the selected spherical cushioning material to form multiple rows of storage spaces for the spherical cushioning material, A procedure for inserting spherical cushioning materials, wherein the selected spherical cushioning materials are inserted into each of the multiple rows of storage spaces, and the spherical cushioning materials in adjacent rows are arranged alternately with an approximate radius offset between them, The process includes inserting the spherical cushioning material until the protective area is covered, joining it with the outermost spherical cushioning material along the outermost outermost line, and removing any excess fabric along the cut line, The aforementioned spherical cushioning material undergoes a pre-impact test or simulated impact test in which a head impactor having the same rigidity as a human head is free-dropped from a height position according to the JCF safety standard toward a collection of cushioning materials arranged in a single layer. The cushioning material is selected based on a shape and material such that the test results using triaxial composite acceleration fall below the defined JCF safety standard. A method for manufacturing an impact-absorbing structure characterized by the above.

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