Cushion structure

Abstract

To provide a cushion structure suitable as a cushion to be laid under a body and suitable for use in a relaxed state.SOLUTION: A ball support member 220 is constituted by laminating two cover sheets 221, and elastically deformable balls 210 are arranged in respective ball housing parts 222 provided with ball swelling opening parts 221a smaller than diameters of the balls 210. Adjacent ball housing parts 222 are fixed to each other, and an interval holding opening part 221c is also formed. When a load is applied to the ball 210, not only an elastic force acts in a vertical direction but also the ball can move in a planar direction. Since the ball support member 220 is formed of the cover sheet 221, the ball is easy to return to the original position after being displaced in the planar direction, and direct contact between the adjacent balls 210 is also prevented.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a cushion structure, and particularly to a cushion structure suitable for use during relaxation such as a sitting posture or a sleeping posture.

Background Art

[0002] Patent Document 1 discloses a technique of using a foamed resin such as polypropylene or polyethylene formed into a plate shape as a cushion material for a vehicle seat. Although the foamed resin is lightweight, it is likely to crack or distort under bending load and compression load. Therefore, although it has not been widely used as a cushion material for vehicle seats, in Patent Document 1, by adhering an elastic coating material having high elongation and recovery rate to the outer surface of the plate-shaped foamed resin molded body, the occurrence of cracks and the like under bending load is prevented, enabling its active application as a cushion material for vehicle seats.

[0003] Patent Document 2 discloses a cushion body filled with foamed particles and crushed low-rebound synthetic resin particles in an outer bag. As the foamed particles, those with a diameter of about 0.5 to 0.8 mm are used, and as the crushed low-rebound synthetic resin particles, those with a diameter of about 1.0 to 1.5 mm are used. By filling them in the outer bag at a predetermined ratio, it is characterized by achieving a balance between the feeling of fitting to the human body due to the fluidity of the foamed particles and the feeling of support due to the elasticity of the crushed low-rebound synthetic resin particles.

Patent Document 1

Patent Document 2

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] The cushioning material disclosed in Patent Document 1 has a spring constant that approximates the spring constant obtained from the load-deflection characteristics obtained by applying pressure at 50 mm / min with a pressure plate of 98 mm or 30 mm in diameter, which is obtained from the load-deflection characteristics obtained by applying pressure to the gluteal muscles of a person under similar conditions. Therefore, it has the characteristic of making it less likely to cause pain in the buttocks and less likely to cause fatigue even when sitting for long periods of time. Accordingly, the inventors considered the structure of this cushioning material to be separated from vehicle seats and used on park benches, the ground, or spectator seats at sports grounds, for use in a sitting or lying position, that is, as a cushioning material for use in a relaxed state. However, it was found that even though such a material has spring characteristics that approximate those of human gluteal muscles when measured using a pressure plate of 98 mm or 30 mm in diameter as described above, users relatively often perceive a hard sitting sensation.

[0005] On the other hand, the product described in Patent Document 2 simply fills an outer bag with foamed particles and crushed low-rebound synthetic resin particles. When seated, these particles flow within the outer bag to conform to the sitter's body shape, providing a comfortable fit. However, the foamed particles tend to become unevenly distributed in the areas where they have flowed, and the sitter may feel the hardness of the foamed particles when they readjust their position. Such a hard seating surface can easily cause muscle and nerve compression and impaired blood flow, leading to numbness and fatigue early after sitting. Therefore, while the product described in Patent Document 2 may not pose much of a problem for short-term use, it is not suitable as a cushioning material for use in a relaxed state and for relatively long periods of continuous use, such as watching sports.

[0006] The present invention has been made in view of the above, and aims to provide a cushion structure that suppresses discomfort such as numbness and fatigue, and is suitable for use in a relaxed state. [Means for solving the problem]

[0007] The cushion structure of the present invention is A cushion structure comprising a ball cushion housed within a cover, The aforementioned ball cushion is It is configured to have a plurality of elastically deformable balls and a ball support member that supports the plurality of balls, The ball support member, It has two laminated covering sheets, Each of the two covering sheets has multiple ball bulging openings formed at intervals in the planar direction, the openings being smaller than the diameter of the ball, and approximately midway between adjacent ball bulging openings, the two covering sheets are fixed together for a predetermined length in a direction approximately perpendicular to a straight line passing through the center of the ball bulging openings, and spacing-maintaining openings are formed within the area surrounded by the multiple ball bulging openings. Between the two covering sheets, when viewed with respect to one ball bulging opening as the center, the area surrounded by multiple fixing portions and multiple spacing-maintaining openings located around it forms a ball-holding portion for one ball. The balls are housed in each ball housing section, with a portion of them bulging out from the ball bulging opening, and the ball covering portion from the ball bulging opening to each fixing portion is housed in close contact with the surface of the ball. It is characterized by the following:

[0008] The ball bulging openings are formed at predetermined intervals in the vertical and horizontal directions, and the fixing portion is provided approximately midway between adjacent ball bulging openings in the vertical or horizontal direction, and the spacing-maintaining opening is formed approximately in the center of the area surrounded by four adjacent ball bulging openings in the vertical and horizontal directions. When viewed with respect to one ball bulging opening as the center, it is preferable that the area surrounded by the four fixing parts and the four spacing-maintaining openings forms the ball housing portion for one ball.

[0009] The aforementioned ball has a diameter of 50-80 mm. In the ball support member, before the ball is housed, the diameter of the ball bulging opening is 25 to 45 mm, the distance between a pair of fixing parts flanking the ball bulging opening along a straight line passing through the ball bulging opening is 80 to 120 mm, and the diameter of the spacing-maintaining opening is 50 to 90 mm. With the balls housed in the ball housing, the distance between the centers of two adjacent balls is 60 to 95 mm. With the ball housed in the ball housing, the height of the ball at its maximum compression is 25-40 mm, and its maximum diameter at that time is 55-90 mm. It is preferable.

[0010] Preferably, the covering sheet is formed from a plastic material, an elastic material, or a viscoelastic material, or a combination of two or more thereof. Furthermore, the balls are gas-injectable balls, and the internal pressure of each ball can be partially varied by changing the amount of gas injected into each ball supported by the ball support member. In this case, it is preferable that the internal pressure of the ball corresponding to the area where concentrated load is applied due to the bony protrusions of the user is set lower than the internal pressure of the other balls. Furthermore, it is preferable that the cover is formed from a three-dimensional knitted fabric. [Effects of the Invention]

[0011] The cushion structure of the present invention is constructed by laminating two covering sheets into a ball support member, and elastically deformable balls are arranged in each ball housing section, which has a ball expansion opening smaller than the diameter of the ball. Adjacent ball housing sections are fixed together, and gap-maintaining openings are also formed. As a result, the balls can move not only in the vertical direction when a load is applied, but also in the horizontal direction. Direct contact between adjacent balls is also prevented. Consequently, balls are not compressed by contact with adjacent balls, and even when used under the body in a seated or lying position, the balls' inherent cushioning properties can be fully utilized, making it suitable for use in a relaxed state.

[0012] Furthermore, by using balls with a diameter of 50-80 mm and configuring the ball storage compartment so that the distance between the centers of two adjacent balls is in the range of 60-95 mm, the device avoids the discomfort of partial pressure on the user's body and is more suitable for use in a relaxed state. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a perspective view showing a portion of a cushion structure according to one embodiment of the present invention. [Figure 2] Figure 2 shows the ball cushion housed inside the cover after the zipper has been opened. [Figure 3] Figure 3 is a plan view of the ball cushion. [Figure 4] Figure 4 is a plan view showing a part of the ball cushion. [Figure 5] Figure 5 is a cross-sectional view showing a portion of the ball cushion. [Figure 6] Figure 6(a) is a plan view showing a part of the ball support member in its deployed state, and Figure 6(b) is a cross-sectional view of a part thereof. [Figure 7]FIG. 7(a) is a perspective view showing an example of a ball cushion with different pressures applied partially, and FIG. 7(b) is a diagram showing the height of the ball when a load of 10 N is applied. [Figure 8] FIG. 8(a) is a view seen from the front direction for explaining a case where a cushion structure is laminated and arranged on a seat portion and a back portion of a chair, and FIG. 8(b) is a view seen from the side direction thereof. [Figure 9] FIG. 9(a) is a view seen from the side direction of the seat cushion structure used in FIG. 8, and FIG. 9(b) is a view seen from the back direction thereof. [Figure 10] FIG. 10(a) is a view seen from the side direction of the back cushion structure used in FIG. 8, and FIG. 10(b) is a view seen from the planar direction of the back cushion structure in a state where it is arranged on the chair of FIGS. 8(a) and (b).

Embodiments for Carrying Out the Invention

[0014] Hereinafter, based on the embodiments of the present invention shown in the drawings, it will be described in more detail. FIGS. 1 and 2 are diagrams showing a cushion structure 100 according to an embodiment of the present invention. The cushion structure 100 of the present embodiment is configured to include a ball cushion 200 and a cover 300.

[0015] As shown in FIGS. 3 to 5, the ball cushion 200 is configured to include a ball 210 and a ball support member 220. The ball 210 is made of an elastically deformable material, and those having a diameter of 100 mm or less, preferably in the range of 50 to 80 mm in diameter, and more preferably in the range of 55 to 75 mm in diameter are used. As long as it has an elastic repulsive force such as rubber, a solid ball may be used, but preferably, it is a ball injected with gas such as a soft tennis ball or a hard tennis ball. It is relatively easy to adjust to a desired elasticity by adjusting the injection amount of the gas.

[0016] Furthermore, by adjusting the amount of gas injected into each ball 210, the internal pressure of all balls 210 placed on the ball support member 220 can be varied rather than uniform. In the case of cushions using urethane pads or the like, it is necessary to design a mold for molding in order to achieve a predetermined shape. However, by using gas-injected balls 210, the amount of gas injected into each ball 210 can be varied depending on the arrangement of the balls 210, allowing for the setting of high-pressure and low-pressure areas at desired locations. In other words, by adjusting the amount of gas injected into the balls 210, the shape of the surface that comes into contact with the back and buttocks can be set to a predetermined shape.

[0017] Furthermore, it is preferable to adjust the amount of gas injected into only the balls 210 located where the user's bones protrude and concentrated load is applied, thereby lowering the internal pressure compared to the other balls 210. This results in a feeling of being enveloped by the cushion structure 100 during use, compared to when all balls 210 have uniform internal pressure, providing superior fit and comfort. For example, in the case of a cushion structure 100 used by inserting it between the backrest of a chair, it is preferable to set the internal pressure of one to several balls 210 located near the spine lower than that of the other balls 210. When used under the buttocks by placing it on the seat of a chair or on the floor or ground, it is preferable to set the internal pressure of one to several balls 210 corresponding to the positions of the ischial tuberosities and coccyx lower than that of the other balls 210.

[0018] The ball support member 220 is composed of two laminated covering sheets 221, 221 (see Figure 5). The covering sheets 221, 221 can be formed from any one of the following: a plastic material, an elastic material, or a viscoelastic material, or a combination of two or more thereof. These materials may be any of the following: a film made of synthetic resin, a fabric or nonwoven fabric made from natural or synthetic fibers, etc. By using a plastic material or a material with low elongation, surface rigidity can be increased, and for example, when used on a bed, a pivot point can be formed when changing posture such as turning over in bed or getting up, thereby supporting these movements. As materials for such covering sheets 221, 221, for example, plastic films made of polyester, polyether, polyamide, polyolefin, or elastomers thereof can be used. Woven fabrics using natural fibers such as cotton or silk are also preferred. These plastic materials or materials with low elongation are also preferred when used, for example, by inserting them between the backrest of a chair and the user's back, because they improve the ability to conform to the user's back. On the other hand, when placed under the buttocks while seated, the load is concentrated on the ischial tuberosities, and shear force acts on the thigh muscles, which can cause nerve compression and impaired blood flow, making it easier for numbness to occur in the buttocks. Therefore, it is preferable to use an elastic film.

[0019] Thus, according to this embodiment, the material of the covering sheets 221, 221 can be used to create a configuration that is less prone to deformation and allows for easy changes in posture, or a configuration that enhances pressure distribution. Furthermore, by using different materials for parts of the covering sheets 221, 221 and other parts, or by using a plastic material (or a material with low elongation) for one of the two covering sheets 221, 221 and an elastic material for the other, various properties can be achieved.

[0020] Each covering sheet 221 has ball bulging openings 221a formed at predetermined intervals in the vertical and horizontal directions, as shown in Figures 4 to 6 in this embodiment, with spacing in the planar direction.

[0021] A fixing portion 221b is formed where two laminated covering sheets 221, 221 are fixed together in a direction substantially perpendicular to the lines P1, P2, over a predetermined length, near the midpoint between adjacent ball bulging openings 221a, 221a, passing through the center of the ball bulging opening 221a and extending outward from the ball bulging opening 221a. The fixing means are not limited, and appropriate means are used depending on the material of the covering sheet 221 used. For example, if it is a woven fabric made of cotton yarn, means such as sewing or bonding are used, and if it is a film made of synthetic resin, means such as welding (vibration welding, etc.) or bonding are used.

[0022] Furthermore, a spacing-maintaining opening 221c is formed approximately in the center of the area surrounded by the four adjacent ball bulging openings 221a arranged vertically and horizontally. The presence of this spacing-maintaining opening 221c makes it easier for the ball 210 to move in the planar direction in conjunction with the ball covering surface 221d, which will be described later, thereby improving its ability to follow body movements.

[0023] When viewed with respect to one ball bulging opening 221a as the center, the area surrounded by the four fixing parts 221b and the four spacing-maintaining openings 221c constitutes the ball housing part 222 for one ball 210.

[0024] Therefore, in the ball housing section 222, of the two covering sheets 221, 221, the area from the ball bulging opening 221a to the four fixing portions 221b located around it constitutes the ball covering surface 221d that covers the surface of the ball 210. Because the ball covering surface 221d is in close contact with the ball 210, as described above, the deformation characteristics when it deforms together with the ball 210 can be varied depending on the type and characteristics of the covering sheets 221, 221.

[0025] When housing the ball 210 in the ball housing section 222, the fixing section 221b is formed to create the ball housing section 222, and then the ball 210 is inserted between the two covering sheets 221 through the ball expansion opening 221a. At this time, the amount of gas injected into the ball 210 is kept small, for example, to about 20-80% of the normal amount, or no gas is injected at all. This allows the ball 210 to be easily deformed, and the ball 210 can be easily inserted through the ball expansion opening 221a, which has a smaller diameter than the ball 210. In this respect as well, it is preferable to use a type of ball 210 that is used by injecting gas rather than a solid ball 210.

[0026] After inserting the ball 210 through the ball inflation opening 221a, gas is injected. As a result, the ball 210 inflates and comes into close contact with the ball covering surface 221d of the two covering sheets 221, 221. At the same time, a portion of the ball 210 expands out through the ball inflation opening 221a formed in each covering sheet 221, 221 and is positioned in the ball housing section 222. During use, the ball 210 is set in place without detaching from the ball inflation opening 221a.

[0027] In the unfolded state of the ball support member 220 before housing the ball 210 as shown in Figure 6 (with the two covering sheets 221, 221 overlapping and flat), the diameter L1 of the ball bulge opening 221a is preferably less than the diameter of the ball 210, more preferably about 1 / 2 to 2 / 3 of the diameter of the ball 210, and if the ball 210 is 50 to 80 mm in diameter, a diameter in the range of 25 to 45 mm is preferred. As a result, a portion of the ball 210 bulges out from each ball bulge opening 221a of the two covering sheets 221, while the surface of the ball 210 is in close contact with each ball covering surface 221c of the two covering sheets 221, 221, preventing it from flying outward through the ball bulge opening 221a.

[0028] In a state where the ball covering surface 221c is in close contact with the ball 210, in order to suppress contact between the balls 210, 210 housed in adjacent ball housing sections 222, 222 in the planar direction, the distance L2 between a pair of fixing sections 221b, 221b that straddle the ball bulging opening 210a along straight lines P1, P2 passing through the ball bulging opening 210a is preferably 80 to 120 mm, and more preferably 90 to 110 mm.

[0029] Furthermore, the diameter of the spacing opening 221c (or the distance between opposite sides if the spacing opening 221c is not circular but, for example, roughly rectangular) is preferably 50 to 90 mm, and more preferably 60 to 80 mm.

[0030] Furthermore, when the ball members 210 with a diameter of 50 to 80 mm are housed in each ball housing section 222, the distance L3 between the centers of two adjacent balls 210, 210 is preferably in the range of 60 to 95 mm, and more preferably in the range of 70 to 85 mm. However, by using a ball support member 220 that satisfies the above shape and dimensional requirements in its unfolded state, the distance L3 between the centers of two adjacent balls 210, 210 when the ball members 210 with a diameter of 50 to 80 mm are inserted into each ball housing section 222 will fall within this range.

[0031] Furthermore, when the ball 210 is housed in the ball housing section 222 and a design load (10-20N) is applied from above, it is preferable that the height H1 of the ball 210 at maximum compression is 25-40 mm, and the maximum diameter W1 at that time is 55-90 mm. Preferably, the elasticity of the ball 210 and the elasticity of the ball support member 220 are selected to satisfy this condition within the range of the above dimensional requirements.

[0032] Furthermore, the number of ball housing sections 222 formed in the ball support member 220, i.e., the number of balls 210 that can be placed, is not limited. It can be adjusted to be the size of a cushion or chair seat if used for sitting, or the size of a bed if used in a lying position.

[0033] The cover 300 is formed in a gusseted bag shape, as shown in Figures 1 and 2, so as to accommodate the ball cushion 200, and is equipped with a zipper 301 on its periphery for opening and closing. The material used to form the cover 300 is not limited, but since it is the surface that comes into contact with people and provides a certain tactile sensation, it is preferable to use a material that is pleasant in texture and feel. For example, felt fabric, velvet fabric, or three-dimensional knitted fabric can be used. However, it is preferable to use a three-dimensional knitted fabric because it has excellent air circulation and can promote ventilation between the inside and outside through the compression and recovery of the material itself.

[0034] A three-dimensional knitted fabric is formed by joining a pair of ground knitted fabrics, spaced apart from each other, with connecting yarns. Each ground knitted fabric can be formed, for example, from twisted yarn into a flat knitted structure (fine stitches) that is continuous in either the wale direction or the course direction, or into a knitted structure with a honeycomb (hexagonal) mesh. The connecting yarns impart a certain rigidity to the three-dimensional knitted fabric so that one ground knitted fabric and the other ground knitted fabric maintain a predetermined distance from each other. Therefore, by applying tension in the planar direction, it becomes possible to cause the yarns of the opposing ground knitted fabrics constituting the three-dimensional knitted fabric, or the connecting yarns that connect the opposing ground knitted fabrics, to vibrate like strings. The movement of the mesh and these yarns promotes ventilation.

[0035] Various materials can be used as the yarn or connecting yarn that forms the ground fabric of a three-dimensional knitted fabric. Examples include synthetic fibers such as polypropylene, polyester, polyamide, polyacrylonitrile, and rayon, as well as regenerated fibers and natural fibers such as wool, silk, and cotton. These materials may be used individually or in combination as desired. Preferably, the materials are polyester fibers such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyamide fibers such as nylon 6 and nylon 66, polyolefin fibers such as polyethylene and polypropylene, or combinations of two or more of these fibers. Furthermore, the shape of the ground yarn or connecting yarn is not limited and may be round cross-section yarn, irregular cross-section yarn, hollow yarn, etc. In addition, carbon yarn, metallic yarn, etc., can also be used.

[0036] Because of its structure, the three-dimensional knitted fabric has the characteristics of high surface rigidity and a low coefficient of friction. Therefore, when the three-dimensional knitted fabric is used as cover 300, it has excellent load distribution properties and can contribute to suppressing numbness and pain even during prolonged use.

[0037] The cushion structure 100 of this embodiment, in which the ball cushions 200 are housed within the cover 300, is used by placing it under the user's body in a seated or lying position. For example, when the cushion structure 1 is used under the buttocks, each ball 210 is compressed by the user's weight. At this time, each ball 210 is placed in a ball housing section 222, and there is a fixing section 221b between adjacent ball housing sections 222, 222, as well as a spacing opening 221c. Therefore, even when compressed and deformed laterally, adjacent balls 210, 210 do not come into contact with each other, and the elastic properties of the balls 210 themselves are exhibited.

[0038] Furthermore, because the distance between the centers of the balls 210, 210 is set as described above, the unevenness of the multiple balls 210, 210 is difficult to perceive within the area in contact with the user, allowing for comfortable use.

[0039] Furthermore, the ball covering surface 221d, which extends from around the ball bulging opening 221a that constitutes each ball housing section 222 and reaches the four fixing sections 221b, is in close contact with the ball 210. As a result, the properties of the covering sheet 221 that constitutes the ball support member 220 also come into play. For example, if a material with low elongation is used as the covering sheet 221, the rigidity increases, and the elastic deformation of the ball 210 is suppressed. This improves the ease of getting up even when placed under the body in a lying position. On the other hand, if a material with high elasticity is used as the covering sheet 221, the pressure distribution can be improved when used under the buttocks, etc. That is, when the ball 210 moves in the planar direction, its elastic reaction force acts, allowing it to follow the user's movement in the planar direction, improving the fit and reducing discomfort.

[0040] Furthermore, by using a three-dimensional knitted fabric as the cover 300, it is possible to help suppress the occurrence of numbness and pain that may occur during prolonged use, as described above. In addition, because it has a mesh structure, it dries easily even when wet from rain, making it suitable for outdoor use.

[0041] Figures 7(a) and 7(b) show examples of ball cushions 200 with desired cushioning properties, where the amount of gas injected into the balls 210 is partially varied. Figure 7(a) shows its appearance, and Figure 7(b) shows the height of each ball 210 when a load of 10N is applied. In Figure 7(b), the numbers in each cell represent the height (in mm) of each ball 210 in Figure 7(a) at the position corresponding to that cell, and the average height of the seven balls 210 belonging to that row is shown to the right of each row. As shown in these figures, the amount of gas injected into the balls 210 is adjusted so that the front two rows, the rear two rows, and the rear three rows are in the order of "high pressure," "medium pressure," and "low pressure." This ball cushion 200 is placed under the buttocks with the thigh side facing the "front" side in the figure, and is used so that, for example, the area around the ischium is in the "medium pressure" to "low pressure" range, and the area around the tailbone is in the "low pressure" range. As a result, the contact area increases in the area from the ischium to the coccyx because the pressure is lower there compared to the high-pressure area. This suppresses the concentration of load on a single point, reduces muscle spasms and compression, and reduces nerve compression near the ischial tuberosity. This reduces the occurrence of numbness and pain from prolonged use. In addition, since the "high-pressure" area corresponds to the area from in front of the ischial tuberosity to below the thigh, a barrier is formed near where the pressure changes, which suppresses the forward sliding of the buttocks, known as buttock sliding. By placing this ball cushion 200 inside the cover 300, a cushion structure 1 with the desired contact surface shape can be provided.

[0042] The cushion structure 100 of this embodiment has multiple balls 210, making it suitable for use in chairs and bed-type human support devices with a predetermined area. For example, it can be used by placing it on the grass seats or wide spectator seats of various sports venues, such as the outfield stands of a baseball stadium, thereby contributing to a more relaxed viewing experience.

[0043] For example, Figures 8(a) and 8(b) show an application example of a chair (a furniture chair for reception, office, etc.) 1000 made using two cushion structures 100A and 100B. The chair 1000 is provided with a seat-side base support section 1100 and a back-side base support section 1200, which incorporate a base net made of a three-dimensional knitted fabric or a two-dimensional woven fabric, and spring members for elastically supporting this base net on the frame. One cushion structure (seat cushion structure) 100A is stacked on the seat-side base support section 1100, and the other cushion structure (back cushion structure) 100B is stacked on the front side of the back-side base support section 1200.

[0044] Each cushion structure 100A and 100B employs a leather cover 300, and the ball cushion 200 with the above configuration is housed inside. Of these, the seat cushion structure 100A has a relatively higher front edge 100A1 and a relatively lower rear edge 100A2, as shown in Figures 9(a) and (b). This is because, among the multiple balls 210 that make up the ball cushion 200, those positioned closer to the front edge 100A1 have higher internal pressure, and those positioned closer to the rear edge 100A2 have lower internal pressure. Each ball 210 is housed with gas injection volume adjustments similar to those shown in Figure 7. Therefore, the seat cushion structure 100A has a high contact area near the ischial tuberosity, resulting in low reaction force, making it less likely for muscle spasms or compression to occur, and also suppressing buttock sliding, providing a stable seating experience.

[0045] As shown in Figure 10(a), the back cushion structure 100B is housed within the cover 300 as a ball cushion 200. The ball 210 positioned closer to the lower edge 100B1 has a higher internal pressure, while the ball 210 positioned closer to the upper edge 100B2 has a lower internal pressure. This allows for support of the area corresponding to the lower back without the need for a separate lumbar support. Furthermore, as shown in Figure 10(b), the area near the center 100B3 in the width direction, corresponding to the spine, is concave and thinner than the areas on either side. That is, the amount of gas injected into the ball 210 corresponding to the center 100B3 in the width direction is reduced compared to the areas on either side, thereby lowering the internal pressure. This increases the contact area with the spine, resulting in a less point-like contact sensation than when the internal pressure of the ball 210 is increased, thus providing a comfortable sitting experience with less pain. As demonstrated in this example, according to this embodiment, the surface shape and cushioning characteristics of the cushion structures 100A and 100B can be adjusted in various ways by adjusting the amount of gas injected into the ball 210. [Explanation of Symbols]

[0046] 100, 100A, 100B Cushion Structure 200 Ball Cushion 210 balls 220 Ball support member 221 Covering sheet 221a Ball expansion opening 221b Fixing part 221c Spacing opening 221d Ball coating surface 222 Ball storage section 300 Cover 301 Zipper

Claims

1. A cushion structure comprising a ball cushion housed within a cover, The aforementioned ball cushion is It is configured to have a plurality of elastically deformable balls and a ball support member that supports the plurality of balls, The ball support member, It has two laminated covering sheets, Each of the two covering sheets has multiple ball bulging openings formed at intervals in the planar direction, the openings being smaller than the diameter of the ball, and approximately midway between adjacent ball bulging openings, the two covering sheets are fixed together for a predetermined length in a direction approximately perpendicular to a straight line passing through the center of the ball bulging openings, and spacing-maintaining openings are formed within the area surrounded by the multiple ball bulging openings. Between the two covering sheets, when viewed with respect to one ball bulging opening as the center, the area surrounded by multiple fixing portions and multiple spacing-maintaining openings located around it forms a ball-holding portion for one ball. The balls are housed in each ball housing section, with a portion of them bulging out from the ball bulging opening, and the ball covering portion from the ball bulging opening to each fixing portion is housed in close contact with the surface of the ball. A cushion structure characterized by the following features.

2. The ball bulging openings are formed at predetermined intervals in the vertical and horizontal directions, and the fixing portion is provided approximately midway between adjacent ball bulging openings in the vertical or horizontal direction, and the spacing-maintaining opening is formed approximately in the center of the area surrounded by four adjacent ball bulging openings in the vertical and horizontal directions. The cushion structure according to claim 1, wherein, when viewed with respect to one ball bulging opening as the center, the area surrounded by four fixing parts and four spacing-maintaining openings forms the ball-accommodating part for one ball.

3. The aforementioned ball has a diameter of 50 to 80 mm. In the ball support member, before the ball is housed, the diameter of the ball bulging opening is 25 to 45 mm, the distance between a pair of fixing parts flanking the ball bulging opening along a straight line passing through the ball bulging opening is 80 to 120 mm, and the diameter of the spacing-maintaining opening is 50 to 90 mm. With the balls housed in the ball housing, the distance between the centers of two adjacent balls is 60 to 95 mm. With the ball housed in the ball housing, the height of the ball at its maximum compression is 25 to 40 mm, and its maximum diameter at that time is 55 to 90 mm. The cushion structure according to claim 1.

4. The cushion structure according to claim 1, wherein the covering sheet is formed of any one of a plastic material, an elastic material, or a viscoelastic material, or a combination of two or more thereof.

5. The cushion structure according to claim 1, wherein the balls are gas-injectable balls, and the internal pressure of each ball is partially different depending on the amount of gas injected into each ball supported by the ball support member.

6. The cushion structure according to claim 5, wherein, among the balls supported by the ball support member, the internal pressure of the ball corresponding to the location where a concentrated load is applied by the bony protrusions of the user is set lower than the internal pressure of the other balls.

7. The cushion structure according to claim 1, wherein the cover is formed from a three-dimensional knitted fabric.

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