Planar coil spring

Abstract

To provide a coil spring structure which is a surface supporting system and in which rolling and creaking sounds are not annoying.SOLUTION: In the surface type coil spring in which a plurality of coil springs are arranged in parallel and end parts form one surface, two or more coil springs are adjacent to one coil spring, and a means having an abutting point where the adjacent coil springs abut against each other and a fixing part for fixing the abutting point is provided during one round of the spiral of either one of the adjacent coil springs.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a surface-type coil spring, and more particularly to a technology for a coil spring that has a constant spring constant over the entire surface or a spring constant whose elasticity is functionally changed in parts of the surface, and that has little lateral vibration or creaking. [Background technology]

[0002] Conventionally, cushions used for beds and sofas have been known as flat springs made of coil springs, and the most common types of cushions using these springs are pocket coil and bonnell coil types. While the pocket coil method fits the body well, it has the disadvantage of causing excessive ups and downs in certain areas. On the other hand, the Bonnell coil system is stable because it provides support over a wide area, but its disadvantages include excessive lateral shaking and annoying creaking noises. Therefore, there was a need for a structure that would provide surface support but would not cause lateral shaking or creaking noises.

[0003] Various techniques have been proposed to address these problems. For example, a technique for partially fixing adjacent coil springs together (see Patent Document 1) has been proposed and is known. More specifically, this technique comprises a spring unit, an elastic member on the top surface of the spring unit, and an exterior body. The spring unit has a structure in which a number of barrel-shaped coil springs are arranged in a matrix, and the middle parts of adjacent springs are connected by a helical wire. However, since the spring is fixed to the adjacent spring at only one point, the lateral vibration cannot be sufficiently reduced, and the above problem is not solved. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-337234 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above problems, the present invention aims to provide a surface-type coil spring that can support the body over a surface while providing high cushioning performance without causing side-to-side shaking or creaking noises. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides a planar coil spring in which multiple coil springs are arranged in parallel, with the ends forming a single surface, and two or more coil springs are adjacent to one coil spring, and the adjacent coil springs have a contact point where they come into contact with each other between one revolution of the spiral of one of the adjacent coil springs, and a fixing part that fixes the contact point.

[0007] In addition, the present invention employs a means for setting the spiral start direction of each coil spring so that, when the direction in which the spiral of the lower end of the coil spring starts relative to the spiral axis of the coil spring is defined as the spiral start direction, there is at least one contact point between adjacent coil springs within one revolution of the spiral of either of the adjacent coil springs.

[0008] Furthermore, the present invention employs a means in which a plurality of coil springs are arranged in a matrix, and the spiral start directions of adjacent coil springs are shifted by 180 degrees.

[0009] Furthermore, the present invention employs a means in which the coil springs are made up of a right-handed coil spring and a left-handed coil spring, with adjacent coil springs having different winding directions.

[0010] Furthermore, the present invention employs a means in which a plurality of coil springs are arranged in a matrix, and the spiral start directions of adjacent coil springs are the same for coil springs in the row direction, and are shifted by 180 degrees from adjacent coil springs in the column direction.

[0011] Furthermore, the present invention employs a means configured with coil springs having different spring constants.

[0012] Furthermore, the present invention employs a means in which the fixing portion is fixed by any one of welding, fusion bonding, resin dipping, and winding fixing. [Effects of the Invention]

[0013] The surface-type coil spring according to the present invention supports the body over a surface area without causing sideways movement or creaking noise, thereby achieving high cushioning performance. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an explanatory diagram showing an embodiment of a surface-type coil spring according to the present invention; [Figure 2] 1 is a perspective view illustrating an embodiment of a surface-type coil spring according to the present invention. [Figure 3] 1 is a schematic plan view illustrating an embodiment of a surface-type coil spring according to the present invention. FIG. [Figure 4] 10A and 10B are explanatory views showing another embodiment of the surface-type coil spring according to the present invention. [Figure 5] FIG. 10 is a plan view showing another embodiment of the surface-type coil spring according to the present invention. [Figure 6] 10A and 10B are explanatory views showing another embodiment of the surface-type coil spring according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The most notable feature of the surface-type coil spring according to the present invention is that it is a surface support system that can eliminate lateral vibration and creaking noise. Hereinafter, an embodiment will be described with reference to the drawings. The overall structure and the structure of each part of the surface-type coil spring according to the present invention are not limited to the examples described below, but can be modified as appropriate within the scope of the technical concept of the present invention, i.e., within the scope of the shape, dimensions, structure, etc. that can achieve the same functional effects.

[0016] The present invention will be described with reference to FIGS. FIG. 1 shows an embodiment of a plane-type coil spring according to the present invention, where (a) is a perspective view and (b) is a plan view. FIG. 2 is a perspective view illustrating an embodiment of a plane-type coil spring according to the present invention, showing one spiral turn. FIG. 3 is a schematic plan view illustrating an embodiment of a flat coil spring according to the present invention, where (a) shows a case where all coil springs are left-handed, and (b) shows a case where right-handed and left-handed coil springs are mixed. FIG. 4 is an explanatory diagram showing another embodiment of the surface-type coil spring according to the present invention, in which (a) is a schematic plan view showing a triangular surface-type coil spring, (b) is a perspective view showing one spiral turn, and (c) is a side view showing one spiral turn. 5A and 5B are plan views showing other embodiments of the surface-type coil spring according to the present invention, where (a) is a schematic plan view showing a hexagonal surface-type coil spring, and (b) is a schematic plan view showing an octagonal surface-type coil spring. 6A and 6B are explanatory diagrams showing another embodiment of the plane-type coil spring according to the present invention, in which (a) is a schematic plan view showing an example in which small coil springs are arranged around a large coil spring, and (b) is a perspective view thereof.

[0017] The plane-type coil spring 1 is formed by arranging a plurality of coil springs in parallel, forming a plane at the ends, and fixing the coil springs 10 together with fixing portions 12. It is mainly used for cushioning mattresses, beds, etc. The surface-type coil spring 1 used in this embodiment is a resilience member used in mattresses and the like, and is arranged so that it can exert an upward resilience force in response to loads mainly directed downward. The coil spring used in this embodiment is, for example, a cylindrical shape with a spiral. It can also be a square or hexagonal prism, as long as it has a columnar spiral structure and can abut adjacent coil springs. The material that makes up the coil spring is either a metal material such as hard steel wire or stainless steel, or a resin material such as plastic, and is determined based on the product specifications of the coil spring. In addition, since both ends of the coil spring constitute the top and bottom surfaces of the coil spring, the coil end portion 14 may be formed in a substantially ring shape so that both ends are perpendicular to the longitudinal direction.

[0018] In the present embodiment, the flat coil spring 1 has two or more coil springs 10 adjacent to one coil spring 10, and has a contact point where the adjacent springs come into contact with each other between one revolution of the spiral of one of the adjacent coil springs, and a fixing part that fixes the contact point. First, an example in which the coil springs 10 are arranged orthogonally and in series and parallel will be described. The coil springs 10 are arranged vertically and horizontally. The portions where the outer circumferences of adjacent coil springs 10 come into contact are called contact points 11. The contact points 11 are fixed with fixtures 20 or the like to form fixed portions 12. The fixing metal fitting 20 is, for example, a wire rod that is wound around and fixed to the contact portion 11. This is just one example, and there are various fixing methods as will be described later. In principle, all of the contact points 11 between adjacent coil springs 10 are fixed portions 12. By fixing adjacent coil springs 10 to each other, creaking noises that occur when the coil springs 10 rub against each other are prevented. Furthermore, since the coil springs 10 are supported by a plurality of coil springs 10, lateral displacement of the coil springs 10 can also be reduced.

[0019] A detailed explanation will be given with reference to Figures 1, 2, and 3. Fig. 1(a) is a perspective view showing an example of orthogonally arranged flat coil springs. As an example of a portion of a flat coil spring, 16 coil springs 10 with the same pitch and the same winding direction are shown in a 4x4 arrangement. Each coil spring 10 has contact points 11 in four directions and is fixed to a fixing bracket 20 as a fixed portion 12. 1(b) is a plan view of the orthogonally arranged plane-type coil springs 1. The coil springs 10 are represented by double circles. The fixing brackets 20 are represented by thick lines connecting the double circles of the coil springs 10. Figure 2 is a schematic perspective view of one spiral turn of the coil springs 10 in the orthogonally arranged plane-type coil spring 1. It consists of nine coil springs 10, with the coil spring 10 represented by the thick line in the center designated A, and the coil springs 10 in the orthogonal directions designated B, C, D, and E. The fixing brackets 20 that secure the coil springs 10 together are designated by thick lines. The coil spring 10 has a bottom end 13 formed with an end turn 14 . The numbers marked on the coil indicate the angles of the positions of the contact portion 11 and the fixed portion 12 when one spiral turn from the lower end 20 is taken as 0 degrees to 360 degrees. Fig. 3 is a plan view of the orthogonal plane-type coil spring 1. It is roughly the same as Fig. 1(b). When the direction in which the spiral at the lower end of the coil spring starts relative to the spiral axis of the coil spring is taken as the spiral starting direction, the spiral starting direction of each coil spring 10 is taken as an angle of 0 degrees, and one spiral revolution from the lower end 20 is taken as 0 degrees to 360 degrees, the angles of the positions of the abutment portion 11 and the fixed portion 12 are represented by numbers. The spiral winding direction is marked "right" or "left" at the center of each coil spring 10. The winding direction is also indicated by an arrow.

[0020] As shown in Figure 1(a), adjacent coil springs 10 are fixed at the position of fixing portion 12, approximately the number of turns of the spiral. When viewed from above, it looks like Figure 1(b). If coil spring 10 A is used as the reference, coil springs 10 B and D are fixed in the vertical direction on the page, and coil springs 10 C and E are fixed in the horizontal direction, so that they are fixed in four directions in total.

[0021] Here, the contact point will be described in detail. The coil springs 10 are arranged perpendicularly, and adjacent coil springs 10 are arranged in four directions around one coil spring 10 so that they abut against each other. However, simply arranging the coil springs 10 may not result in a point of abutment. Therefore, in terms of the topological meaning of the spiral of each coil spring 10, the direction in which the spiral at the lower end of the coil spring starts relative to the spiral axis of the coil spring is defined as the spiral start direction. For example, if coil springs with the same spiral start direction and pitch are arranged side by side, the contact point 11 will not occur. In order to have at least one contact point between adjacent coil springs 10 during one spiral turn of either of the adjacent coil springs, the spiral start direction of adjacent coil springs must be changed by 180 degrees, as shown in Figure 3(a).

[0022] An explanation will be given using examples of arrangements of the coil springs 10 A to E in FIG. 3(a). The spiral start direction of A (angle 0 degrees) is the downward direction on the page. Next, the spiral start direction of the adjacent coil spring 10, B, is the upward direction on the page, which is shifted by 180 degrees from A. Therefore, the lower end portion, which is the spiral start part of A, and the lower end portion, which is the spiral start part of B, are at an angle of 0 degrees to each other, so they abut against each other. In the relationship between A and C, the angle of A on the C side is 90 degrees, and the angle of C on the A side is also 90 degrees, so they abut. Similarly, A and D, and A and E, meet at angles of 180 degrees and 270 degrees, respectively, and come into contact. In this way, when coil springs 10 with the same pitch and the same winding direction are gathered together, by shifting the spiral start direction of adjacent coil springs by 180 degrees, it is possible for adjacent springs to come into contact with each other more than once during one revolution of the spiral. Figure 2 is a perspective view including coil springs 10 A to E. Only one cycle of each coil spring 10 is shown. A and B abut at an angle of 0 and are fixed with fixtures 20 to form fixed part 12. Similarly, A and C abut at an angle of 90 degrees. A and D abut at an angle of 180 degrees. A and E abut at an angle of 270 degrees. In this way, by appropriately setting the spiral start direction of each coil spring 10, it is possible to make a plane-type coil spring having contact points and fixed portions in four directions.

[0023] Next, we will explain the case where coil springs with both left and right winding directions are used. If only coil springs with either left or right winding directions are used, when a lateral force is applied to the coil, the direction in which the coil is likely to distort will be the same. By using coil springs with both left and right winding directions, the direction in which the coil is likely to distort can be dispersed, resulting in a surface-type coil spring that is more stable against lateral forces. FIG. 3(b) shows an example of the arrangement of coil springs when using both left-handed and right-handed coil springs. The coil springs 10 are made up of a right-handed spring and a left-handed spring, and adjacent coil springs 10 have different winding directions. The spiral start directions of adjacent coil springs in the row direction are all the same, but the spiral start directions of adjacent coil springs in the column direction are 180 degrees different. An example of the arrangement of the coil springs 10 shown in FIG. 3(b) from A to E will be described. The spiral start direction of A is upward and downward on the page. Next, the spiral start direction of the adjacent coil spring 10, B, is upward on the page, which is 180 degrees different from A. Therefore, the lower end portion, which is the spiral start part of A, and the lower end portion, which is the spiral start part of B, are at an angle of 0 degrees to each other, so they abut against each other. In the relationship between A and C, the starting direction of the spiral of C is downward, just like A. Since it is clockwise, the angle of the direction of A is 90 degrees. Therefore, it matches and abuts with the 90 degrees of A. Similarly, A and D, and A and E, meet at angles of 180 degrees and 270 degrees, respectively, and come into contact. In this way, when coil springs 10 with the same pitch but different winding directions are gathered together, by adjusting the winding direction and spiral start direction of adjacent coil springs as described above, it is possible to have adjacent springs come into contact with each other more than once during one revolution of the spiral. In other words, the planar coil spring 1 consists of a right-handed coil spring 10 and a left-handed coil spring 10, and adjacent coil springs 10 have different winding directions, and multiple coil springs 10 are arranged in a matrix, with the spiral starting directions of adjacent coil springs 10 being the same for coil springs in the row direction and shifting 180 degrees between adjacent coil springs in the column direction.

[0024] In this way, by adjusting the spiral start direction, etc., the angles of adjacent coil springs 10 can all be matched to form fixed portions 12, so that the coil springs 10 can be firmly fixed to each other. In this way, by arranging multiple coil springs in a planar manner, with two or more coil springs adjacent to one coil spring, and having a contact point where adjacent springs come into contact between one revolution of the spiral of one of the adjacent coil springs, and having a fixing part to fix the contact point, it is possible to create a planar spring that is resistant to lateral shaking and does not creak. The spiral start position of a coil spring is the position where the coil spring comes into contact with the adjacent coil spring at least once during one revolution of the spiral. Furthermore, by using coil springs 10 with different spring constants, the elasticity of a portion of the integrated planar coil spring 1 can be changed.

[0025] The fixing method for the fixing portion 12 may be, for example, welding using metal, bonding with adhesive, dipping with resin (a processing method in which the part is immersed in liquid resin and then cooled to fix), melt joining or welding in which heat is applied to plastic to soften and melt it for fixing, or wrapping and fixing in which tape is wrapped around the fixing point. In particular, by being fixed by welding, resin dipping, or winding, fixing can be achieved without using any special construction method, which simplifies the work. Also, when the coil spring expands or contracts, the crossing angle of the fixing portion 12 does not change due to the fixation, which may cause a load. However, the amount of expansion and contraction of the coil spring 10 depends on the height and number of turns of the coil itself. For example, even if the coil spring 10 has a diameter of 2 mm, a height of 50 mm, and four turns, it will only expand and contract by approximately 10 mm, and even when the maximum load is applied, it will be possible to expand and contract without putting a large load on the fixing portion 5. Furthermore, when using a resin material such as plastic as the material for the coil spring, instead of stacking coil springs 10 molded separately and fixing the contact points by melt-jointing or the like, it is also possible to initially mold the flat coil spring 1 in an overlapping state by bringing the coils into contact with each other through extrusion molding, and it is also possible to adopt a form in which the contact points are already fixed during such extrusion molding.

[0026] In this way, according to this embodiment, since multiple coil springs can be integrated into a flat surface, when used in a bed or mattress, it is possible to prevent the occurrence of surface irregularities. Furthermore, by fixing the coil springs together at multiple points, it is possible to suppress the generation of creaking noises and reduce lateral displacement of the coil springs.

[0027] Furthermore, by making the entire mattress a single flat coil spring, the labor required to line up the coil springs is eliminated, improving production efficiency.

[0028] Although the example in which the coil springs 10 are arranged orthogonally has been described, they may be arranged in various polygonal shapes such as triangular, hexagonal, octagonal, etc. Examples of arrangements in triangular, hexagonal, and octagonal shapes will be described with reference to Figures 4, 5, and 6. When the coil springs 10 contact each other in a triangular manner, the coil springs 10 contact each other at an angle of 60 degrees (FIG. 4(a)). In this case, if all three coil springs 10 have the same pitch, one coil spring 10 will not come into contact with the other even if the spiral start position is changed. Therefore, as an example, a case where the pitch of one coil spring 10 is halved will be described. Three coil springs 10 are arranged as A, B, and C as shown in FIG. 4(a). The pitch of coil spring 10 of A is half that of the other coil springs 10. In other words, the coil spring 10 of A has one spiral rotation compared to the two spiral rotations of coil springs 10 of B and C. B and C have the same pitch and the same winding direction (left), and are in contact at an angle of 120 degrees. With respect to A, B needs to be in contact at 60 degrees, and C at 180 degrees. Position A at an angle of 30 degrees so that it faces B. Because the pitch of A is half that of B, the height of A at an angle of 30 degrees corresponds to the angle of B at 60 degrees. Therefore, A and B come into contact (T1). In this state, the 90-degree angle of A faces the 180-degree angle of C. The height of the 90-degree angle of A corresponds to the height of the 180-degree angle of C, so A and C come into contact (T2). Fig. 4(b) is a perspective view showing the state in which they come into contact, and Fig. 4(c) is a side view showing the state in which they come into contact. By making it triangular, it is possible to make a surface-type coil spring that has a larger receiving area than a normal coil spring, even though the number of coil springs is small.

[0029] The cases of hexagonal and octagonal shapes will be explained with reference to FIG. The hexagonal shape is similar to the triangular shape described above. In the case of a hexagonal shape, as in the case of a triangular shape, it is not possible to make a hexagonal shape with coil springs 10 of the same pitch. It is necessary to include coil springs 10 of different pitches. In FIG. 5(a), an example in which the triangular shape of FIG. 4 is used in part will be described. A, B, and C have the same configuration as in the triangular case. A is right-handed and BG is left-handed. As in the case of the triangular shape, the positions are arranged so that A at a helical angle of 30 degrees faces B at a helical angle of 60 degrees, A at a helical angle of 90 degrees faces C at a helical angle of 180 degrees, and A at a helical angle of 150 degrees faces D at a helical angle of 300 degrees. With this arrangement, A comes into contact with the first turn of the spiral of B, C, and D. Similarly, A's spiral angle of 210 degrees faces E's spiral angle of 60 degrees. At the 180-degree position, A has the same meaning as 0 degrees relative to E, so it becomes 30 degrees instead of 210 degrees. Similarly, F's spiral angle of 180 degrees faces A's spiral angle of 90 degrees. Also, G's spiral angle of 300 degrees faces A's spiral angle of 150 degrees. This arrangement places A in contact with the second turn of the spiral of E, F, and G. In this state, if we check the contact state of B to G with each other, we find that B and C are contacting at an angle of 120 degrees, C and D are contacting at an angle of 240 degrees, D and E are contacting at an angle of 0 degrees, E and F are contacting at an angle of 120 degrees, F and G are contacting at an angle of 240 degrees, and G and B are contacting at an angle of 0 degrees. Therefore, A and B to G are in contact with each other within one revolution of A's spiral, and B to G are in contact with each other within one revolution of their spiral.

[0030] The hexagonal shape maximizes the density of the coil springs 10. Since the pitch of one of the seven coil springs 10 is half, the spring constant of the other coil springs 10 can be made the same by changing the elastic constant.

[0031] It can also be octagonal, as shown in Figure 5(b). Eight coil springs 10 are arranged around a central point. The spiral start points face the center, and the right-handed and left-handed springs are arranged alternately. When this is done, the springs come into contact at angles of 67.5 degrees and 292.5 degrees, forming the contact points 11. Specifically, when the coil spring 10 of A is left-handed, the coil spring 10 of B, which is adjacent to it on the left on the paper, is right-handed, and A and B abut at an angle of 292.5 degrees. The coil spring 10 of C, which is adjacent to A on the right, is clockwise, and A and C abut at an angle of 67.5 degrees. By using the contact point 11 as the fixed portion 12, the coil spring 10 can be integrated.

[0032] Also, a configuration in which a large coil spring 10 is arranged in the center and small coil springs 10 are arranged around it will be described with reference to FIG. This is the case where eight small springs are arranged. The small springs are arranged in the same manner as in Figure 5(b). When the large coil spring 10 in the center is designated as A, A and the surrounding coil springs come into contact with each other in turn, roughly for each full spiral turn. To be precise, if the pitch of the surrounding coil springs is 1, the pitch of A is 7 / 8. Therefore, A contacts the surrounding coil springs every 7 / 8 of a turn. By making 8 turns in the spiral, A contacts all 8 surrounding coil springs. Figures 6(a) and (b) show an example in which the coil spring of B first contacts A (T1), and then when A has made 7 / 8 of a turn, it contacts the coil spring of C (T2). In this example, the number of surrounding coil springs is eight, but any number greater than or equal to four may be used. With this configuration, the central coil spring can be used as the main spring, and the surrounding coil springs can be used to fine-tune the characteristics.

[0033] In this way, the planar coil spring can be configured in a shape other than the orthogonal shape.

[0034] Furthermore, by making all of the contact points into fixed portions, it is possible to fix the coil springs to each other to the maximum extent possible, which is preferable. Furthermore, by making all the coil springs the same diameter, production control is easy, and when used in beds and mattresses, layout is easy and convenient. Furthermore, by making each coil spring a multiple coil spring made up of a plurality of springs, it is possible to change the characteristics of each individual coil spring, which is preferable. Furthermore, when the surface-type coil spring 1 is used in a bed or mattress, the characteristics of the surface-type coil spring can be changed depending on the position of the bed or mattress, which is preferable as it allows for a comfortable bed or mattress to be created.

[0035] In this way, the planar coil spring according to the present invention can provide high cushioning performance by supporting the body over a surface without causing sideways movement or creaking noises.

[0036] Furthermore, by using the contact point where adjacent springs abut between one revolution of the spiral of adjacent coil springs as the fixing part, it is possible to have multiple fixing parts depending on the number of turns of the spiral, and therefore the coil springs can be fixed to each other extremely firmly.

[0037] Furthermore, by specifying the spiral start direction, which is the direction in which the spiral at the bottom end of each coil spring starts, relative to the spiral axis of each coil spring, it is possible to accurately manage the contact portion.

[0038] Furthermore, by arranging multiple coil springs in a matrix, the layout is similar to that of a typical coil spring, making it possible to utilize the characteristics of a planar coil spring while making use of existing know-how.

[0039] Furthermore, by using coil springs with different winding directions, it is possible to make the device more resistant to lateral displacement and bending. [Industrial Applicability]

[0040] It is understood that the surface-type coil spring according to the present invention has great industrial applicability as a coil spring with little lateral vibration or creaking. [Explanation of symbols]

[0041] Single-sided coil spring 10 coil springs 11 Contact point 12 Fixed part 13 Lower end 14 End winding section 20 Fixing bracket

Claims

1. A flat coil spring in which a plurality of coil springs are arranged in parallel and the ends form a single surface, Two or more of the coil springs are adjacent to one of the coil springs, The coil springs each have an abutment point between two adjacent coil springs, between one turn of the spiral of the coil spring, A surface-type coil spring characterized by having a fixing portion for fixing the corresponding contact.

2. When the direction in which the spiral of the lower end of the coil spring starts relative to the spiral axis of the coil spring is defined as the spiral start direction, 2. The plane-type coil spring according to claim 1, wherein the spiral start direction of each of the coil springs is set so that there is one or more contact points where adjacent coil springs abut against each other within one spiral turn of any of the adjacent coil springs.

3. A plurality of the coil springs are arranged in a matrix, 3. The plane-type coil spring according to claim 2, wherein the spiral start directions of adjacent coil springs are offset by 180 degrees.

4. The coil spring comprises a right-handed coil spring and a left-handed coil spring, 3. The plane-type coil spring according to claim 2, wherein adjacent coil springs have different winding directions.

5. A plurality of the coil springs are arranged in a matrix, 5. The plane-type coil spring according to claim 4, wherein the spiral start directions of adjacent coil springs are the same for the coil springs in the row direction, and are shifted by 180 degrees between adjacent coil springs in the column direction.

6. 3. The plane-type coil spring according to claim 2, wherein the coil springs have different spring constants.

7. 7. The plane-type coil spring according to claim 1, wherein the fixing portion is fixed by any one of welding, adhesion, resin dipping, and winding.

Images