Mattress and mattress unit

Abstract

To provide a mattress that has improved the easiness of turning over.SOLUTION: A mattress 1 includes a cushion material of at least three layers of a first layer 11, a second layer 12, and a third layer 13 each having a predetermined thickness. In a thickness direction, the second layer 12 is interposed between the first layer 11 and the third layer 13. The rebound resilience of the second layer 12 is lower than that of the first layer 11 and the third layer 13. The thickness t3 of the third layer 13 is equal to or larger than the thickness adding up the thickness t1 of the first layer 11 and the thickness t2 of the second layer 12. The first layer 11 and the second layer 12 are formed with a groove 5 that penetrates the first layer 11 in the thickness direction and continues to at least part of the second layer 12. In a plane view from the surface of the first layer 11, the groove 5 is formed by a continuous and / or non-continuous straight line and / or a curved line.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a mattress with improved roll-over performance.

Background Art

[0002] Conventionally, a mattress has been proposed that aims to achieve both a soft sleeping comfort and an appropriate sleeping posture. For example, the mattress described in Patent Document 1 is formed by laminating a plurality of polyfoam cushioning materials with gradually increasing hardness from the upper layer to the lower layer, and the plurality of polyfoam cushioning materials with different hardnesses are laminated so that the hardness gradually increases from the upper layer to the lower layer. A plurality of slits extending from the upper surface to the lower surface are formed such that at least one side of the slit approaches the end of an adjacent slit. The above slits have a planar shape of an I shape or a Y shape. And it is covered with a side fabric using a fabric that flexibly stretches at least on the surface in contact with the body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the mattress exemplified by Patent Document 1 is laminated so that the hardness gradually increases from the upper layer to the lower layer. When a user lays their body on the mattress, the sinking depth becomes deeper. Then, there is a problem that it becomes difficult to roll over because the hips and the like sink excessively in the sleeping posture.

[0005] An object of the present invention is to solve the conventional problems and to provide a mattress with improved roll-over performance.

Means for Solving the Problems

[0006] A mattress according to a first aspect of the present invention comprises at least three layers of cushioning material, a first layer, a second layer, and a third layer, each having a predetermined thickness, wherein in the thickness direction, the second layer is sandwiched and stacked between the first layer and the third layer, and the second layer has a lower rebound modulus than the first layer and the third layer.

[0007] According to this, the second layer has a lower rebound modulus than the first and third layers, so the second layer is the first of the three layers to begin to compress. Therefore, it can suppress excessive sinking of the body and improve the ability to turn over in bed.

[0008] Furthermore, the rebound elasticity of the first and third layers of the mattress may be in the range of 15 to 60%, and the rebound elasticity of the second layer may be in the range of 5 to 30%.

[0009] In this case, since the first and third layers, and the second layer, each have appropriate rebound moduli, the second layer is the first of the three layers to begin to compress. Therefore, excessive sinking of the body is suppressed, and the ability to turn over in bed is improved.

[0010] Furthermore, the thickness of the third layer of the mattress may be greater than or equal to the sum of the thickness of the first layer and the thickness of the second layer.

[0011] In this case, the thickness of the third layer is greater than or equal to the combined thickness of the first and second layers, thus suppressing the feeling of bottoming out against the bed frame or floor that the user experiences.

[0012] Furthermore, the second layer of the mattress may have a greater capacity for ventilation than the first and third layers.

[0013] In this case, the second layer has greater ventilation than the first and third layers, so when the user leans their body against the surface of the first layer, it provides a function of air circulation from the second layer.

[0014] Furthermore, the mattress may have grooves formed in the first layer and the second layer, penetrating the first layer in the thickness direction and continuing to at least a portion of the second layer, and these grooves may be formed by continuous and / or discontinuous straight lines and / or curves in a plan view from the surface of the first layer.

[0015] In this case, the groove penetrates the first layer and continues to form at least a portion of the second layer, allowing for the distribution of body pressure when the user leans against it.

[0016] A mattress according to a second aspect of the present invention comprises at least two layers of cushioning material, a first layer and a second layer, each having a predetermined thickness, wherein the first layer and the second layer are stacked in the thickness direction, the second layer has a lower rebound modulus than the first layer, and grooves are formed in at least a portion of the second layer that penetrate the first layer and continue to the second layer in the thickness direction.

[0017] According to this, the second layer has a lower rebound modulus than the first layer, and grooves are formed in at least a portion of the second layer, penetrating the first layer and continuing onward. Therefore, when the user leans back, it can improve the ability to turn over in their sleep and distribute body pressure.

[0018] A mattress according to a third aspect of the present invention comprises at least two layers of cushioning material, a first layer and a second layer, each having a predetermined thickness, wherein the first layer and the second layer are stacked in the thickness direction, and the second layer has a greater air permeability than the first layer. In the thickness direction, a groove is formed that penetrates at least the aforementioned layer.

[0019] According to this, the second layer has greater breathability than the first layer, and grooves are formed that penetrate at least the first layer. Therefore, when the user leans their body against it, body pressure is distributed, and the grooves further enhance the air circulation function from the surface of the first layer to the second layer.

[0020] The mattress unit according to the fourth aspect of the present invention is a mattress unit formed by arranging a plurality of the mattresses, wherein the mattress forms a rectangular plane with one direction as the column direction and the other direction as the row direction, at least a part of the grooves is formed along the column direction, and the mattresses are arranged by bringing the end portions in the row direction into contact with each other.

[0021] According to this, when a user places their body on the mattress unit, the boundary portion functions to disperse body pressure in the same manner as the groove row.

Brief Description of the Drawings

[0022] [Figure 1] It is a perspective view showing the mattress 1 according to the first aspect of the present invention. [Figure 2] Among the mattresses 1 of the present invention, etc., it is a plan view of the first mattress 1a in which the groove 5 has a first groove shape. [Figure 3] Among the mattresses 1 of the present invention, etc., it is a plan view of the second mattress 1b in which the groove 5 has a second groove shape. [Figure 4] Among the mattresses 1 of the present invention, etc., it is a plan view of the third mattress 1c in which the groove 5 has a third groove shape. [Figure 5] Among the mattresses 1 of the present invention, etc., it is a plan view of the fourth mattress 1d in which the groove 5 has a fourth groove shape. [Figure 6] Among the mattresses 1 of the present invention, etc., it is a plan view of the fifth mattress 1e in which the groove 5 has a fifth groove shape. [Figure 7] It is a cross-sectional view of the mattress 1 according to the first aspect of the present invention, where (a) shows the case where the groove 5 is not formed, (b) shows the case where the groove 5q penetrates the first layer 11 and is further continuously formed in a part of the second layer 12a, and (c) shows the case where the groove 5p continuously penetrates the first layer 11 and the second layer 12a. [Figure 8]This is a cross-sectional view of a mattress 1 according to a first aspect of the present invention, particularly when the second layer 12b is formed of defilm-treated urethane foam, where (a) shows a case where groove 5 is not formed, (b) shows a case where groove 5q penetrates the first layer 11 and continues to be formed in a part of the second layer 12b, (c) shows a case where groove 5p continuously penetrates the first layer 11 and the second layer 12b, and (d) is a conceptual diagram of an enlarged view of the surface of the second layer 12b. [Figure 9] These figures show the state in which a load is applied to mattress 1. (a) shows the state in which a load is applied to mattress 1f in Figure 7(a), and (b) shows the state in which a load is applied to mattress 1h in Figure 7(c). [Figure 10] This diagram shows the state of a person turning over in their sleep on mattress 1, etc. (a) shows the state of mattress 1 of the present invention, (b) shows the state of mattress 100 which has a higher rebound modulus than the present invention, and (c) shows the state of mattress 110 which has a lower rebound modulus than the present invention. [Figure 11] This is a cross-sectional view of a mattress 20 according to a second aspect of the present invention, where (a) shows a case where groove 5 is not formed, (b) shows a case where groove 5q penetrates the first layer 21 and is further formed continuously in a part of the second layer 22, and (c) shows a case where groove 5p continuously penetrates the first layer 21 and the second layer 22. [Figure 12] This is a cross-sectional view of a mattress 30 according to a third aspect of the present invention, in which the second layer 32 is formed of defilm-treated urethane foam, where (a) shows a case where no groove 5 is formed, (b) shows a case where groove 5q is formed penetrating the first layer 31, and (c) shows a case where groove 5p continuously penetrates the first layer 31 and the second layer 32. [Figure 13] This is a plan view of a mattress unit 10a according to a fourth aspect of the present invention, in which the mattress 1 etc. according to the first to third aspects of the present invention is formed by arranging the row direction along the longitudinal direction. [Figure 14] This is a plan view of a mattress unit 10b according to a fifth aspect of the present invention, in which the mattress 1 etc. according to the first to third aspects of the present invention is formed by arranging the row direction along the longitudinal direction. [Modes for carrying out the invention]

[0023] The following description will refer to the drawings and explain mattress 1 and other items embodying the present invention. The embodiments for carrying out the invention and the referenced drawings are used to illustrate the technical features that the present invention may adopt. The present invention is not limited to these. The configurations shown in the drawings are not intended to limit the invention to these configurations, but are merely illustrative examples.

[0024] The example shown in Figure 1 is a perspective view showing the first mattress 1a as a representative example from the mattress 1 etc. according to the present invention. Hereinafter, mattress 1, mattress 20, and mattress 30 (mattress 20 and mattress 30 will be described later) will be referred to as mattress 1 etc. Mattress 1 etc. forms a rectangular plane with one side in the column direction and the other side in the row direction, and has a predetermined thickness in the thickness direction. As an example, in the example shown in Figure 1, the thickness direction has a three-layer structure consisting of a first layer 11, a second layer 12, and a third layer 13.

[0025] Figures 2 to 6 are plan views showing the shape of the groove 5 in mattress 1, etc. Figures 7 to 12 are cross-sectional views showing the cross-sectional shape of mattress 1, etc. Figures 7(a), 8(a), 11(a), and 12(a) show the configuration when the groove 5 is not formed. For explanatory purposes, among mattresses 1, etc., the types showing the shape of the groove 5 are designated as the first mattress 1a to the fifth mattress 1e, and the types showing the cross-sectional shape in the thickness direction are designated as mattress 1f to mattress 30m. Mattresses 1, etc. are constructed by a combination of the shape of each groove 5 and the cross-sectional shape in the thickness direction.

[0026] <<Configuration and Effects of Mattress 1 in the First Embodiment>> <Mattress 1 Composition> Referring to Figures 7 and 8, the configuration of the mattress 1 according to the first aspect of the present invention will first be described in the thickness direction. The mattress 1 comprises at least three layers of cushioning material, a first layer 11, a second layer 12, and a third layer 13, each having a predetermined thickness. In the thickness direction, the second layer 12 is sandwiched and stacked between the first layer 11 and the third layer 13. The second layer 12 has a lower rebound modulus than the first layer 11 and the third layer 13. Although Figures 7 and 8 show the configuration for three layers in the thickness direction, there may be four or more layers.

[0027] Next, the rebound moduli of the first layer 11, the second layer 12, and the third layer 13 will be described. The rebound moduli of the first layer 11 and the third layer 13 are in the range of 15 to 60%, and the rebound moduli of the second layer 12 are in the range of 5 to 30%. The maximum value of the rebound moduli of the second layer 12 is greater than the minimum value of the rebound moduli of the first layer 11 and the third layer 13, but the rebound moduli of the second layer 12 is set within a range that satisfies the condition that the rebound moduli of the second layer 12 are lower than those of the first layer 11 and the third layer 13. Here, the measured values ​​of the rebound moduli are in accordance with the measurement standard JIS K 6400-3.

[0028] Furthermore, the following relationship is more preferable for the rebound moduli of the first layer 11, the second layer 12, and the third layer 13: the rebound moduli of the first layer 11 and the third layer 13 are in the range of 40-50%, and the rebound moduli of the second layer 12 are in the range of 18-25%. Note that the rebound moduli are values ​​of the materials constituting each layer.

[0029] In this embodiment, the density of the first layer 11 and the third layer 13 is 35 to 55 kg per cubic meter, and the hardness is 136 to 196 N. The density of the second layer 12 is 25 to 45 kg per cubic meter, and the hardness is 54 to 94 N. The density and hardness are values ​​for the materials constituting the first layer 11 to the third layer 13. The material for the first layer 11 to the third layer 13 is preferably urethane foam, but may also be olefin foam such as polyethylene, rubber foam, fibers, etc. Here, the density is measured according to the measurement standard JIS K 7222. The hardness is measured according to the measurement standard JIS K 6400-2D method (25% compression).

[0030] The relationship between the rebound elasticity moduli of the first layer 11 to the third layer 13, as explained above, produces the following effects. Since the second layer 12 has a lower rebound elasticity moduli than the first layer 11 and the third layer 13, when the user leans their body onto the mattress 1, the second layer 12 is the first of the three layers to begin to compress. The first layer 11 compresses less than the second layer 12, and a constant rebound force is maintained. Therefore, the mattress 1 can suppress excessive sinking of the body and improve ease of turning over in bed by having the first layer 11 firmly press back against the body.

[0031] Figure 9 shows the state of mattress 1 when a load is applied. Figure 9(a) shows mattress 1f in which groove 5, described later, is not formed, and Figure 9(b) shows mattress 1h in which groove 5 is formed. In both configurations, when a load is applied, the second layer 12, which has a low rebound modulus, is compressed to absorb the load, and the first layer 11, which has a high rebound modulus, pushes back against the load or suppresses excessive sinking.

[0032] Furthermore, the rebound modulus of the first layer 11 and the third layer 13 are within the range of 15-60%, and the rebound modulus of the second layer 12 is within the range of 5-30%. Therefore, by manufacturing each layer within a certain tolerance range for its rebound modulus, it is possible to maintain the ability to turn over in bed while improving productivity, including cost reduction.

[0033] Furthermore, by improving manufacturing controllability and setting the rebound elasticity of the first layer 11 and the third layer 13 within the range of 40-50%, and the rebound elasticity of the second layer 12 within the range of 18-25%, it is possible to stabilize the quality that contributes to improved turning ability. Note that the following explanation includes cases where the mattress 1 has grooves 5. However, even in cases where there are no grooves 5, such as mattress 1f shown in Figure 7(a) and mattress 1j shown in Figure 8(a), setting the rebound elasticity of each layer to the above configuration has the effect of improving turning ability.

[0034] <Relationship and effect of the thickness of each layer> Next, the thicknesses of the first layer 11 to the third layer 13 in mattress 1 will be explained with reference to Figures 7 and 8. Figure 7 shows that the first layer 11 to the third layer 13 are made of the same material, and the second layer 12a is not subjected to the defilm processing described later. Figure 8 shows that the second layer 12b is subjected to defilm processing to increase the amount of air permeability, as will be described later. The thickness t3 of the third layer 13 is greater than or equal to the sum of the thickness t1 of the first layer 11 and the thickness t2 of the second layer 12. More preferably, the thickness t1 of the first layer 11 and the thickness t2 of the second layer 12 are approximately the same, and the thickness t3 of the third layer 13 is approximately 1.5 times the sum of the thickness t1 of the first layer 11 and the thickness t2 of the second layer 12. Specifically, t1 and t2 are 10 to 30 mm, and t3 is 50 to 70 mm. Preferably, t1 and t2 are 20 mm, and t3 is 60 mm.

[0035] The following effects are achieved due to the relationship of the thicknesses of each layer as described above. The thickness t3 of the third layer 13 is greater than or equal to the sum of the thickness t1 of the first layer 11 and the thickness t2 of the second layer 12, thus suppressing the feeling of bottoming out that the user experiences against the bed frame or floor. Furthermore, if the thickness t1 of the first layer 11 and the thickness t2 of the second layer 12 are approximately the same, and the thickness t3 of the third layer 13 is approximately 1.5 times the sum of the thickness t1 of the first layer 11 and the thickness t2 of the second layer 12, the feeling of bottoming out can be suppressed even further. By setting the third layer 13, which has a certain degree of high rebound elasticity, to a predetermined thickness, the feeling of bottoming out can be suppressed. Furthermore, by satisfying the relationship of the rebound elasticity of each layer as described above, the feeling of bottoming out can be suppressed even further, and the effect of improving the ease of turning over in bed is enhanced.

[0036] As the thickness t1 of the first layer 11 and the thickness t2 of the second layer 12 increase, the effect of distributing body pressure improves. In particular, as the thickness t2 of the second layer 12 increases, the effect of distributing body pressure improves even more. However, this results in deeper sinking, which reduces the ability to turn over in bed and the feeling of bottoming out. Therefore, by setting the thickness of each layer within the range of the thickness t1 of the first layer 11, the thickness t2 of the second layer 12, and the thickness t3 of the third layer 13 as described above, a good balance can be obtained between the ability to turn over in bed, the effect of distributing body pressure, and the effect of suppressing the feeling of bottoming out.

[0037] <<Explanation of the structure and effect of groove 5>> <Structure of groove 5> Next, the grooves 5 formed in the first layer 11 and the second layer 12 will be described with reference to Figures 1 to 6. In the first layer 11 and the second layer 12, grooves 5 are formed in the thickness direction, penetrating the first layer 11 and continuing to at least a portion of the second layer 12. The grooves 5 are formed by continuous and / or discontinuous straight lines and / or curves when viewed from the surface of the first layer 11 in plan view. The examples shown in Figures 2 to 6 are mattresses such as mattress 1, and the same applies not only to the three-layer mattress 1 but also to the two-layer mattresses 20 and 30.

[0038] As shown in Figures 2 to 6, the vertical direction of the figures is defined as the column direction, and the horizontal direction as the row direction. The center line C indicates the center in the row direction. Each column in the column direction is defined as L1 to L8, and so on. The number of columns and rows is arbitrary. In the examples shown in Figures 1 to 6, the center line C with respect to the row direction is between columns L4 and L5, and in a plan view from the surface of the first layer 11, the shape in which the grooves 5 are formed is symmetrical in the row direction with respect to the center line C. As shown in Figure 1, the column direction is the column spacing L, and the row direction is the row spacing D, both of which are constant intervals. For example, the column spacing L is 84 mm and the row spacing D is 97 mm. Note that the planar shape formed by the grooves 5 is not limited to the examples shown in Figures 1 to 6.

[0039] Next, the depth of the groove 5 in the thickness direction will be explained with reference to Figures 7 and 8. Figure 7(a) shows mattress 1f in which no groove 5 is formed in either the first layer 11 or the second layer 12. In mattress 1g shown in Figure 7(b) and mattress 1k shown in Figure 8(b), in the thickness direction, the groove 5 penetrates the first layer 11 and continues to be formed in a part of the second layer 12. The depth of the groove 5 in the second layer 12 can be set arbitrarily. In mattress 1h shown in Figure 7(c) and mattress 1m shown in Figure 8(c), the groove 5 continues through the first layer 11 and the second layer 12 and penetrates to the boundary with the third layer 13. The depth of the groove 5 is preferably in the range of 30 to 50 mm. Furthermore, a range of 35 to 45 mm is more preferable. This is because if the depth of the groove 5 is shallow, the effect of pressure distribution decreases and the ability to turn over in bed also decreases.

[0040] Next, the shape formed by the grooves 5 in a plan view from the surface of the first layer 11 will be described. The mattress 1, etc., has multiple triangles 15 formed by the grooves 5. The triangles 15 include at least one of three types: a first triangle 15a in which the grooves 5 are discontinuous at three vertices, a second triangle 15b in which the grooves 5 are discontinuous at two vertices, and a third triangle 15c in which the grooves 5 are discontinuous at one vertex.

[0041] <Effects of groove 5> As described above, the configuration of groove 5 produces the following effects. Since groove 5 is formed in the mattress 1, penetrating the first layer 11 and continuing to at least a portion of the second layer 12, body pressure can be distributed when the user rests their body on the mattress. The degree of body pressure distribution can be adjusted by the depth of groove 5 in the thickness direction. The effect of distributing body pressure is greatest when groove 5 is continuous with the first layer 11 and the second layer 12 and penetrates to the boundary with the third layer 13. Conversely, the effect of distributing body pressure decreases as the depth of groove 5 in the second layer 12 after penetrating the first layer 11 decreases, but sufficient effect can be achieved if the rebound elasticity of the first layer 11 is set to be higher than that of the second layer 12 within a certain range. In addition, groove 5 also contributes to improving the ease of turning over in bed by distributing body pressure. As shown in Figure 9(b), when the user leans their body against the mattress, the groove 5 partially separates the first layer 11 and the second layer 12, thereby preventing the entire surface of the first layer 11 from sinking and limiting the area that sinks. Therefore, the mattress 1 can improve the ability to turn over in bed.

[0042] Furthermore, as an example, at point A1 of groove 5a shown in Figure 2(b), grooves 5 intersect and connect at the point forming the vertex of triangle 15. Similarly, grooves 5 intersect at point A2 of groove 5f shown in Figure 3(b), at point A3 of groove 5h shown in Figure 4(b), at point A1 of groove 5a and at point A2 of groove 5f shown in Figure 5(b), and at points A4 and A5 of groove 5j shown in Figure 6(b). In mattress 1, when a user leans their body against it, their shoulders or hip bones, etc., are more likely to sink into the mattress if they come into contact with the points where grooves 5 intersect. The points where grooves 5 intersect are scattered across the entire surface of mattress 1. When a user tries to turn over in their sleep, their shoulders or hip bones, etc., are supported at the points where grooves 5 intersect. Therefore, the user can easily turn over in their sleep.

[0043] <Overall effect of each element> As explained above, mattress 1 achieves its effects through each of its three elements. Specifically, the rebound elasticity of the first layer 11 to the third layer 13 is within an appropriate range, improving the ease of turning over in bed. The thickness of each layer from the first layer 11 to the third layer 13 is within an appropriate range, which suppresses the feeling of bottoming out against the bed frame or floor. Furthermore, the grooves 5 are formed to an appropriate depth, which distributes body pressure. The following describes the effects achieved not only by each element individually, but also by the combined effect of each element.

[0044] Referring to Figure 10, the turning ability of mattress 1 will be explained. Figures 10(a) to 10(c) are diagrams that compare and explain the effects of differences in rebound modulus and groove depth 5 in each mattress 1 (100, 110). From left to right, they show the state from when the user is lying on their back to when they turn over and lie on their side. Figure 10(a) shows the case of mattress 1 of the present invention. That is, the rebound modulus of the first layer 11 to the third layer 13 is within an appropriate range, the thickness of each layer from the first layer 11 to the third layer 13 is within an appropriate range, and the groove 5 is formed to an appropriate depth.

[0045] According to this, the rebound elasticity of the first layer 11 to the third layer 13 is within an appropriate range, allowing the user's body to sink in appropriately and improving ease of turning over in bed. The grooves 5 are formed to an appropriate depth, enveloping the protruding parts of the body and distributing body pressure. When the user turns onto their side, the shoulders and waist sink in due to the grooves 5 (there is the necessary sinking), improving ease of turning over in bed. Furthermore, the feeling of the user bottoming out against the bed frame or floor is suppressed. Therefore, mattress 1 can simultaneously achieve multiple effects through the combined action of each element being set within an appropriate range.

[0046] In contrast, Figure 10(b) shows the case of mattress 100 where the rebound modulus is higher than the appropriate range and groove 5 is not formed. Because mattress 100 has a high rebound modulus, the body does not sink in as much, and it is easy to turn over in bed. However, because mattress 100 does not sink in as much, the distance traveled when turning over in bed is longer, and the body is more prone to wobbling. Furthermore, when lying on one's side, the pressure on the shoulders increases.

[0047] Furthermore, Figure 10(c) shows the case of mattress 110 in which the rebound elasticity is lower than the appropriate range and the depth of the groove 5 is deeper than the appropriate range. Although mattress 110 has an improved pressure distribution effect, the body sinks in excessively due to the low rebound elasticity. The user will have difficulty moving their body and will have to use extra muscle strength. This is because the first layer 11 in contact with the body is compressed and no force is generated to push back.

[0048] Next, we will describe the shape formed by the grooves 5 in a plan view from the surface of the first layer 11. As already explained, the mattress 1 etc. has multiple triangles 15 formed by the grooves 5. Below, we will describe the respective forms of the first mattress 1a to the fifth mattress 1e.

[0049] <Configuration from the first mattress 1a with a first groove shape to the third mattress 1c with a third groove shape> Referring to Figures 2 to 4, the configurations of the first mattress 1a to the third mattress 1c will be described. In the first mattress 1a to the third mattress 1c, in a plan view from the surface of the first layer 11, multiple triangles 15 are formed by the grooves 5. The triangles 15 include at least one of three types: a first triangle 15a in which the grooves 5 are discontinuous at three vertices, a second triangle 15b in which the grooves 5 are discontinuous at two vertices, and a third triangle 15c in which the grooves 5 are discontinuous at one vertex. In the example of the first mattress 1a to the third mattress 1c, except for columns L1 and L8 which are the ends in the row direction, one type of triangle 15 (one of 15a, 15b, or 15c) is formed by the grooves 5 in each column.

[0050] Figure 2 shows the first mattress 1a when the groove 5 has the first groove shape. There are two patterns for the first groove shape. The first pattern shown in Figure 2(b) shows the groove pattern of the groove 5 from column L2 to column L7. The second pattern shown in Figure 2(c) shows the groove pattern of the groove 5 at the ends in the row direction, columns L1 and L8.

[0051] As shown in Figures 2(a) and 2(b), the first pattern is arranged in the column direction, with an inverted V-shaped groove 5b formed at the upper end and multiple inverted Y-shaped grooves 5a formed at other positions. As shown in Figure 2(b), in the inverted Y shape, the groove width is W and the length of one side is S. For example, the groove width W is 6 mm and the side length S is 81 mm. The side length S is the same for each side in the inverted Y shape. The groove width W is also 6 mm in the other parts of the groove 5. As shown in Figure 2(c), the second pattern is formed at one end in the row direction, with an inverted V-shaped groove 5d that is shorter on the side at the row direction. At other positions, multiple inverted Y-shaped grooves 5c with shorter sides at the row direction and diagonal straight grooves 5e are formed in a row along the column direction.

[0052] As shown in Figure 2(a), a groove 5b formed at one end in the row direction and grooves 5a formed in the column and row directions, offset from each other, form a plurality of first triangles 15a. The first triangles 15a may be equilateral or isosceles triangles. The same applies to the second triangles 15b and third triangles 15c described below. In the first triangles 15a, all three vertices are formed by discontinuous grooves 5, and each vertex connects to an adjacent first triangle 15a. The grooves 5 are formed to a predetermined depth from the surface of the first layer 11 toward the second layer 12.

[0053] As shown in Figure 2(b), the groove 5a is connected by a curve 50 where the straight sections intersect. The point where the tip of the groove 5a intersects with the straight section is an arc-shaped curve 50. Similarly, the groove 5b is connected by a curve 50 where the straight sections intersect. In grooves 5c, 5d, and 5e shown in Figure 2(c), the points where the straight sections intersect and the tips are formed by curves 50, respectively. Note that each straight section of the groove 5 is not limited to a straight line, but may also be a curve. Similarly, in the examples shown in Figures 3 to 6, the tips of the grooves 5 and the points where the grooves 5 intersect are formed by curves 50. Since the intersections and tips of the grooves 5 are formed by curves 50, the occurrence of cracks can be reduced. Note that the points where the curves 50 are formed may be simply intersections of straight lines instead of arc shapes. The radii of the curves 50 may all be the same or they may all be different.

[0054] <Effects of First Mattress 1a> As explained above, the first mattress 1a with the first groove shape has the following effects. When a user rests their body on the surface of the first layer 11, the first triangle 15a in the area in contact with the body deforms in accordance with the movement of the body, with the groove 5 acting as a buffer area. Since the first triangle 15a in the first mattress 1a is formed by grooves 5 on which none of the three sides are continuous with each other, all three vertices are connected to the other first triangles 15a. Therefore, when the first triangle 15a deforms with the groove 5 acting as a buffer area, it works to suppress the amount of deformation of each other with the other first triangles 15a. When a user rests their body, the rebound elasticity of the first mattress 1a in the three-layer structure from the first layer 11 to the third layer 13 (including the two-layer structure of the first layer 11 and the second layer 12 described later) maintains a certain rebound force, maintains the ability to turn over in bed, and has the effect of distributing body pressure.

[0055] <Configuration of the second mattress 1b with a second groove shape> Figure 3 shows the second mattress 1b when groove 5 has the second groove shape. There are two patterns for the groove shape of the second mattress 1b. The first pattern shown in Figure 3(b) shows the pattern of groove 5 from column L2 to column L7. The first pattern is groove 5f in which groove 5 is connected in the column direction relative to the groove shape in Figure 2(b). Groove 5f is a shape that is connected in the column direction relative to the groove shape in Figure 2(b), and is formed in the row direction while being alternately offset in the column direction. The second pattern shown in Figure 3(c) shows the pattern of groove 5 in columns L1 and L8, which are the ends in the row direction. Groove 5g is a shape that is continuously connected in the column direction relative to the groove shape in Figure 2(c). Groove 5e is the same as in Figure 2(c).

[0056] As shown in Figure 3, in a plan view on the surface of the first layer 11, the second mattress 1b forms multiple second triangles 15b. One of the three vertices of the second triangles 15b is connected by a groove 5, and the two sides flanking the vertices that are formed in a continuous sequence are also formed by grooves 5.

[0057] <Effects of the second mattress 1b> As explained above, the second mattress 1b with the second groove shape has the following effects. Compared to the first triangle 15a of the first mattress 1a shown in Figure 2, the second triangle 15b has grooves 5 connected at one vertex, so it has a higher degree of freedom when deforming. Therefore, compared to the first mattress 1a, the rebound force when the user leans on it is reduced to a certain extent, but the effect of distributing body pressure is greater.

[0058] <Configuration of the third mattress 1c with a third groove shape> Figure 4 shows the third mattress 1c when groove 5 has the shape of a third groove. The third mattress 1c is formed by grooves 5h in which groove 5 is continuously connected in all diagonal lines D1 that cross the row direction in a downward-sloping direction to the right, and in all diagonal lines D3 that cross in an upward-sloping direction to the right, relative to the groove shape shown in Figure 2. Rows L1 and L8 have non-continuous ends of diagonal lines D1 and D3, as shown in Figure 4(c).

[0059] As shown in Figure 4, in a plan view on the surface of the first layer 11, the third mattress 1c forms multiple third triangles 15c and a parallelogram 25. Two of the three vertices of the third triangle 15c are connected by grooves 5, and one vertex is continuous with an adjacent third triangle 15c. The parallelogram 25 is continuous around its perimeter by grooves 5 and is formed by combining two third triangles 15c.

[0060] <Effects of the Third Mattress 1c> As explained above, the third mattress 1c with the third groove shape has the following effects. Compared to the second triangle 15b of the second mattress 1b shown in Figure 3, the third triangle 15c has grooves 5 connected at two vertices, so it has a higher degree of freedom when deforming. Furthermore, in addition to the third triangle 15c, a parallelogram 25 is formed by the continuous grooves 5 around the perimeter, so it has an even higher degree of freedom. Therefore, compared to the second mattress 1b, the rebound force when the user leans on it is further reduced, but the effect of pressure distribution is greater.

[0061] As explained above, the first mattress 1a through the third mattress 1c differ in their pressure distribution effect and degree of rebound force depending on their respective compositions. Improved ease of turning over in bed can be achieved through the synergistic effect of pressure distribution and a certain degree of rebound force. Therefore, users can choose any of the first mattress 1a through the third mattress 1c based on the feeling they experience when resting their body on it.

[0062] <Configuration of the fourth mattress 1d with a fourth groove shape and the fifth mattress 1e with a fifth groove shape> Next, with reference to Figures 5 and 6, the groove shape in the fourth mattress 1d and the fifth mattress 1e as seen from the surface of the first layer 11 will be described. The triangles 15 formed in the fourth mattress 1d and the fifth mattress 1e by the grooves 5 include at least two of the three types: the first triangle 15a, the second triangle 15b, and the third triangle 15c. What distinguishes these from the first mattresses 1a to the third mattresses 1c is that multiple types of triangles 15 are formed by the grooves 5.

[0063] <Configuration of the fourth mattress 1d with a fourth groove shape> Figure 5 shows the fourth mattress 1d when the groove 5 has the fourth groove shape. The fourth mattress 1d differs from the first mattress 1a shown in Figure 2 in the following respects. As shown in Figure 5(a), grooves 5f are formed at the boundaries between rows L1 and L2, between rows L3 and L4, between rows L5 and L6, and between rows L7 and L8 in the row direction, where grooves 5 are continuous in the row direction. That is, grooves 5 are continuously formed in the row direction every other row. As shown in Figure 5(b), the fourth groove shape is formed by grooves 5a, 5b, 5f, 5g, and 5e.

[0064] As shown in Figures 5(a) and 5(b), the fourth groove shape is a mixture of the first triangle 15a and the second triangle 15b. As shown in Figure 5(a), the first triangle 15a is a grid-like hatching area tilted at 45 degrees, and the second triangle 15b is a grid-like hatching area without tilt. For explanatory purposes, the hatching areas are shown only in some rows. The first triangle 15a and the second triangle 15b are arranged along the row direction and formed alternately in the column direction.

[0065] <Effects of the Fourth Mattress 1d> As explained above, the fourth groove shape of the fourth mattress 1d has the following effects. While the first to third groove shapes each form only triangles of the same type 15, the fourth groove shape is formed by a mixture of two types of triangles: the first triangle 15a and the second triangle 15b. Therefore, an intermediate effect between that of the first shape of the first mattress 1a and the second shape of the second mattress 1b can be obtained approximately uniformly on the surface of the first layer 11 in terms of the generation of rebound force and distribution of body pressure when the user leans on it. Furthermore, it can combine the characteristics of both the first mattress 1a and the second mattress 1b. In the example shown in Figure 5, the first triangle 15a and the second triangle 15b are arranged approximately equally, but depending on the application, they may be divided, for example, into the center and near both ends in the row direction, or biased in the column direction, and various other configurations are possible.

[0066] <Configuration of the fifth mattress 1e with a fifth groove shape> Next, the fifth mattress 1e will be described when the groove 5 has the fifth groove shape, with reference to Figure 6. As shown in Figure 6(a), the groove shape in plan view on the surface of the first layer 11 of the fifth mattress 1e is formed by grooves 5j, where groove 5 is continuous in diagonal lines D1 that cross the row direction downward to the right and diagonal lines D3 that cross the row direction upward to the right, relative to the first mattress 1a shown in Figure 2. Diagonal lines D1, where groove 5 is continuous, and diagonal lines D2, which are parallel to diagonal line D1 and do not have continuous grooves 5, are formed alternately in the column direction. The relationship between diagonal lines D3, where groove 5 is continuous, and diagonal lines D4, which are parallel to diagonal line D3 and do not have continuous grooves 5, is similar. As shown in Figures 6(a) and 6(b), the fifth groove shape is formed by grooves 5a, 5b, 5e, and 5j.

[0067] As shown in Figures 6(a) and 6(b), the fifth groove shape is a mixture of the first triangle 15a, the second triangle 15b, and the third triangle 15c. As shown in Figure 6(a), the first triangle 15a is a grid-like hatching area tilted at 45 degrees, the second triangle 15b is a grid-like hatching area without tilt, and the third triangle 15c is a hatching area with parallel lines. For explanatory purposes, hatching is indicated only in some rows.

[0068] <Effects of Mattress 1e (Fifth Mattress)> As explained above, the fifth groove shape of the fifth mattress 1e has the following effects. While the first mattress 1a with the first groove shape to the third mattress 1c with the third groove shape each have only one type of triangle 15 formed on them, the fifth groove shape is formed by a mixture of three types of triangles: the first triangle 15a, the second triangle 15b, and the third triangle 15c. Therefore, the effects of the first mattress 1a with the first groove shape to the third mattress 1c with the third groove shape on the surface of the first layer 11 can be obtained almost uniformly on the surface of the first layer 11 in terms of generating rebound force and distributing body pressure when the user leans on it. Furthermore, it can combine the characteristics of each of the first mattresses 1a to the third mattresses 1c.

[0069] In the example shown in Figure 6, the diagonal lines D1 and D2, and D3 and D4 are formed alternately so that the first triangle 15a, the second triangle 15b, and the third triangle 15c are arranged to be approximately equal in size. However, the arrangement is not limited to this, and depending on the application, for example, the diagonal lines D1 and D2, and D3 and D4 may be arranged unevenly, allowing for various configurations.

[0070] As described above, the fourth mattress 1d and the fifth mattress 1e can form multiple triangles 15 by the grooves 5, so it is possible to arrange partially different triangles 15 on a single mattress 1, etc. Various options are available depending on the intended use of the mattress 1, etc.

[0071] <Explanation of ventilation volume and effects for each layer> Next, we will explain the air permeability of each layer from the first layer 11 to the third layer 13. From mattress 1j to mattress 1m shown in Figure 8, the cushioning material of the second layer 12b has a greater air permeability than the cushioning materials of the first layer 11 and the third layer 13. Here, air permeability refers to the airflow rate determined by the JIS standard K6400-7A method. The air permeability of each layer should satisfy the relationship that the air permeability of the second layer 12b is greater than that of the first layer 11 and the third layer 13. Specifically, the air permeability of the first layer 11 and the third layer 13 should be 60-80 L / min, and the air permeability of the second layer 12 should preferably be 210-270 L / min.

[0072] Next, the second layer 12b will be described. The second layer 12b is processed to increase the air permeability by performing a defilm treatment on the urethane foam. The defilm treatment can be any method that is normally used to remove the cell membrane, such as a method of removing the cell membrane by the blast of combustion gas, a hydrolysis treatment with alkali, the use of special silicone as a foam stabilizer, or the use of a defilm remover. Figure 8(d) is an enlarged view showing the state of the cells 23 of the second layer 12b after defilm treatment. The urethane foam molded body has multiple cells 23, and the cell membranes of the surface cells 23 are removed by the defilm treatment. By removing the cell membranes, the air permeability is improved and the amount of air permeability is increased. The structure of the second layer 12b is the same as that of the second layer 32 of the mattress 30, which will be described later.

[0073] As explained above, the relationship of air permeability in each layer produces the following effects. Mattress 1 is required to have a function that circulates air containing heat and / or moisture generated by body temperature and sweating when the user uses mattress 1. In response to this, mattress 1 (1j~1m) has a function of circulating air from the second layer 12 when the user rests their body on the surface of the first layer 11, as the air permeability of the second layer 12 is greater than that of the first layer 11 and the third layer 13. In particular, as shown in Figures 1 to 6, and Figures 8(b) and 8(c), the effect of the air circulation function is greater when grooves 5 are formed. That is, grooves 5 are formed that penetrate the first layer 11 in contact with the user's body and continue into a part of the second layer 12 which has a high air permeability. Therefore, air containing heat and / or moisture generated by body temperature and sweating flows directly into the second layer 12b. Mattress 1 (1j~1m) has the effect of having a high function of circulating air containing heat and / or moisture.

[0074] Furthermore, mattress 1 (1j~1m), by combining the elements described above, not only enhances the circulation of air containing heat and / or moisture, but also improves the ease of turning over in bed, / and enhances the distribution of body pressure, and / or reduces the feeling of bottoming out against the bed frame or floor, as previously described. However, mattress 1 has a need to enhance the circulation of air containing heat and / or moisture, regardless of the effects of improving the ease of turning over in bed, / and the distribution of body pressure, and / or the reduction of the feeling of bottoming out.

[0075] In contrast, mattress 1 (1j~1m) may have the following configuration. That is, mattress 1 (1j~1m) only needs to have a greater ventilation rate in the second layer 12b than in the first layer 11 and the third layer 13. It is not limited to the relationship between the thickness t1 of the first layer 11, the thickness t2 of the second layer 12, and the thickness t3 of the third layer 13 as shown in Figure 8. The rebound modulus of the second layer 12b may be the same as or higher than that of the first layer 11 and / or the third layer 13.

[0076] Furthermore, as shown in Figure 8(a), even if groove 5 is not formed, the air circulation function can be enhanced if the air permeability of the second layer 12b is high. Moreover, the depth of groove 5 in the thickness direction does not have to be formed in a part of the second layer 12b, as shown in groove 5q in Figure 8(b); the air circulation function can be further enhanced if it penetrates at least the first layer 11. This is because the heat and / or moisture generated from the body flows through the first layer 11 to the second layer 12b, which has a higher air permeability, thus further enhancing the air circulation function.

[0077] <<Configuration and Effects of Mattress 20 in the Second Embodiment>> <Composition of Mattress 20> Next, the configuration of the mattress 20 (20f~20h) according to the second aspect of the present invention will be described. It differs from the mattress 1 according to the first aspect described earlier in its configuration in the thickness direction. Note that the example of the shape of the groove 5 in a plan view from the surface of the first layer 11 (21, 31), shown in Figures 2 to 6, is common to mattress 1, mattress 20, and mattress 30, which will be described later.

[0078] The mattress 20 comprises at least two layers of cushioning material, a first layer 21 and a second layer 22, each having a predetermined thickness. In the thickness direction, the first layer 21 and the second layer 22 are stacked on top of each other, and the second layer 22 has a lower rebound modulus than the first layer 21. Also, in the thickness direction, a groove 5 is formed in at least a portion of the second layer 22, penetrating the first layer 21 and continuing thereafter. It should be noted that since the mattress 20 comprises at least two layers of cushioning material, it naturally also includes configurations comprising three layers of cushioning material.

[0079] Next, the rebound elasticity modulus of the cushioning material in each layer of the mattress 20 will be explained. The rebound elasticity modulus of the first layer 21 is in the range of 15-60%, and the rebound elasticity modulus of the second layer 22 is in the range of 5-30%. Furthermore, it is more preferable that the rebound elasticity modulus of the first layer 21 is in the range of 40-50%, and the rebound elasticity modulus of the second layer 22 is in the range of 18-25%. These ranges of rebound elasticity modulus are similar to the relationship between the first layer 11 and the second layer 12 in mattress 1, and the evaluation results in Table 1 can be applied.

[0080] Next, with reference to Figure 11, the thickness configuration of the mattress 20 will be explained. As with Figure 7, Figure 11 shows that the cushioning material of the first layer 21 and the second layer 22 are made of the same material. The thickness t21 of the first layer 21 and the thickness t22 of the second layer 22 may be approximately the same, or the thickness t22 of the second layer 22 may be greater than or less than the thickness t21 of the first layer 21.

[0081] Next, the configuration of the grooves 5 in the mattress 20 will be explained. Referring to Figure 11, the depth of the grooves 5 in the thickness direction will be explained. Figure 11(a) shows a mattress 20f in which no grooves 5 are formed in either the first layer 21 or the second layer 22. In the example shown in Figure 11(b), similar to Figures 7(b) and 8(b), a mattress 20g is shown in which the grooves 5 penetrate the first layer 21 in the thickness direction and are continuously formed in a part of the second layer 22. The depth of the grooves 5 in the second layer 22 can be set arbitrarily. In the example shown in Figure 11(c), a mattress 20h is shown in which the grooves 5 continuously penetrate both the first layer 21 and the second layer 22.

[0082] <Effects of Mattress 20> As described above, the mattress 20 according to the second aspect of the present invention provides the following effects. In order to reduce manufacturing costs, it is desirable for the mattress 20 to improve the ability to turn over in bed and distribute body pressure with fewer layers of cushioning material. In response to this, the mattress 20 has a second layer 22 with a lower rebound elasticity than the first layer 21, and grooves 5 are formed in at least a part of the second layer 22 that penetrate the first layer 21 and continue further. Therefore, when the user leans their body on the mattress, it is possible to improve the ability to turn over in bed and distribute body pressure.

[0083] Furthermore, similar to mattress 1 already described, by setting the rebound elasticity of the first layer 21 to a range of 15-60% and the rebound elasticity of the second layer 22 to a range of 5-30%, the rebound elasticity of each layer can be kept within a certain range during manufacturing, thereby improving productivity, including cost reduction, while also improving the ability to turn over in bed.

[0084] Furthermore, by improving manufacturing controllability and setting the rebound elasticity of the first layer 21 within the range of 40-50%, and the rebound elasticity of the second layer 22 within the range of 18-25%, the ability to turn over in bed can be further improved.

[0085] <<Configuration and Effects of Mattress 30 in the Third Embodiment>> <Composition of Mattress 30> Next, the configuration of the mattress 30 according to a third aspect of the present invention will be described. As shown in Figure 12, the mattress 30 comprises at least two layers of cushioning material, a first layer 31 and a second layer 32, each having a predetermined thickness. In the thickness direction, the first layer 31 and the second layer 32 are stacked on top of each other, and the second layer 32 has a greater capacity for ventilation than the first layer 31. Furthermore, in the thickness direction, grooves 5 are formed that penetrate at least the first layer 31. It should be noted that since the mattress 30 comprises at least two layers of cushioning material, it naturally also includes configurations comprising three layers of cushioning material.

[0086] Mattress 30 differs from mattress 20 in the configuration of its second layer 32. Figure 12 shows the case where the second layer 32 has been defilmed and processed to increase the amount of air permeability compared to Figure 11. The thickness t31 of the first layer 31 and the thickness t32 of the second layer 32 may be approximately the same, or the thickness t32 of the second layer 32 may be greater or less than the thickness t31 of the first layer 31.

[0087] Figure 12(a) shows a mattress 30j in which no groove 5 is formed in either the first layer 31 or the second layer 32. Figure 12(b) shows a mattress 30k in which the groove 5q penetrates from the surface of the first layer 31 to the boundary with the second layer 32. Note that, as in Figure 11(b), the groove 5q may also be formed in part of the second layer 32. Figure 12(c) shows a mattress 30m in which the groove 5p continuously penetrates both the first layer 31 and the second layer 32.

[0088] Next, we will explain the air permeability of the first layer 31 and the second layer 32. From mattress 30j to mattress 30m shown in Figure 12, the cushioning material of the second layer 32 has a higher air permeability than the cushioning material of the first layer 11. The air permeability of each layer should satisfy the relationship that the air permeability of the second layer 32 is greater than that of the first layer 31. Specifically, the air permeability of the first layer 31 should be 60-80 L / min, and the air permeability of the second layer 32 should be 210-270 L / min.

[0089] <Effects of Mattress 30> As described above, the mattress 30 according to the third aspect of the present invention has the following effects. In order to reduce manufacturing costs, it is desirable for the mattress 30 to enhance the function of circulating heat and / or moisture generated from the body with fewer layers of cushioning material. In response to this, the mattress 30 has a function of circulating air from the second layer 32 when the user rests their body on the surface of the first layer 31, because the second layer 32 has a greater capacity for air permeability than the first layer 31. In particular, as shown in Figures 1 to 6 and Figures 12(b) and 12(c), the effect of the air circulation function is greater when grooves 5 are formed. That is, since grooves 5 are formed continuously through the first layer 31 in contact with the user's body and at least to the boundary with the second layer 32, air containing heat and / or moisture generated by body temperature and sweating flows directly to the second layer 32. Therefore, the mattress 30 has the effect of having a high function of circulating air containing heat and / or moisture.

[0090] Furthermore, regarding the first layer 21 and the second layer 22, mattress 20 specifies the elements of rebound modulus and groove 5, while mattress 30 specifies the element of air permeability; however, these elements may be combined.

[0091] <Explanation of usage of mattress type 1, etc.> Next, the usage configuration of mattress 1, etc. will be described. Mattress 1, etc. may be formed as a single unit to match the user's height, build, etc., or multiple units may be arranged to form a unit. When using mattress 1, etc. as a single unit, the column direction may be aligned with the user's height direction, or the row direction may be aligned with the user's height direction. Referring to Figures 13 and 14, a mattress unit 10 formed by arranging multiple mattresses 1, etc. will be described. As already described, the mattress 1, etc. used in the mattress unit 10 forms a rectangular plane with one direction as the column direction and the other as the row direction. The direction along the user's height direction is the longitudinal direction, and the direction perpendicular to the longitudinal direction is the width direction.

[0092] The mattress unit 10 may be covered with a cover member while multiple mattresses 1 etc. are arranged side by side. Alternatively, the mattresses 1 etc. may be joined together by joining, sewing, or other means at the boundary portions 24 (26) where they touch each other. Alternatively, the mattresses 1 etc. may simply be arranged side by side.

[0093] <Configuration and effects of the mattress unit 10a of the first embodiment> A mattress unit 10a, which is a first embodiment of the mattress unit 10, will be described. As shown in Figure 13, the mattress unit 10a uses a mattress 1, etc., in which at least a portion of the grooves 5 are formed along the row direction. The mattress unit 10a is formed by arranging the ends of the mattress 1, etc. in the row direction so that they are in contact with each other at the boundary portion 24. In the mattress unit 10a, a portion of the grooves 5 are connected in the width direction to form a groove row 35, which is substantially parallel to the boundary portion 24 in which the mattresses 1, etc. are in contact with each other.

[0094] The mattress unit 10a described above provides the following effects. The mattress unit 10, which is formed by arranging multiple mattresses 1, etc., requires that the user be able to use it without discomfort at the boundary 24. In this regard, when the user leans their body on the mattress unit 10a, the boundary 24 functions to distribute body pressure in the same way as the groove row 35. Therefore, even if a part of the user's body comes into contact with the boundary 24, discomfort is suppressed.

[0095] <Configuration and effects of the mattress unit 10b of the second embodiment> A second embodiment of mattress unit 10, mattress unit 10b, will now be described. As shown in Figure 14, mattress unit 10b uses mattress 1, etc., in which at least a portion of the grooves 5 are formed along the row direction. Mattress unit 10b is formed by arranging the ends of mattress 1, etc., in the row direction so that they are in contact with each other at the boundary portion 26.

[0096] The mattress unit 10b described above provides the following effects. A mattress unit 10, formed by arranging multiple mattresses 1, etc., requires improved ease of turning over, similar to when using a mattress 1, etc. individually. In contrast, since the groove row 35 of the mattress unit 10b is aligned in the longitudinal direction, the user can lean their body with their height aligned with the direction of the groove row 35. Therefore, the user can turn over more easily.

[0097] Note that when arranging multiple mattresses 1, etc., in mattress unit 10a and mattress unit 10b, the same type of mattress 1, etc. may be arranged. Alternatively, different types of mattresses 1, etc. may be arranged, as shown in the following configuration.

[0098] The mattress unit 10 may have the following configuration for the mattress 1 used: that is, it may include at least two of the following: a first mattress 1a in which a first triangle 15a is formed by groove 5, a second mattress 1b in which a second triangle 15b is formed by groove 5, and a third mattress 1c in which a third triangle 15c is formed by groove 5.

[0099] In this case, the mattress unit 10 can be configured to select appropriate characteristics (such as ease of turning over, distribution of body position, degree of bottoming out, and other aspects of sleeping comfort) depending on the part of the body that comes into contact with the mattress when the user rests their body on it, by arranging different types of mattresses 1, etc.

[0100] Furthermore, the mattress unit 10 may include the following mattresses 1 etc.: that is, it may include at least one of a fourth mattress 1d formed by grooves 5 including a first triangle 15a and a second triangle 15b, and a fifth mattress 1e formed by grooves 5 including a first triangle 15a, a second triangle 15b, and a third triangle 15c.

[0101] In this case, the mattress unit 10 can be configured to further select characteristics (such as ease of turning over, distribution of body position, degree of bottoming out, and other aspects of sleeping comfort) according to the parts of the body that come into contact with the mattress when the user rests their body on it, by arranging different types of mattresses 1, etc. [Explanation of Symbols]

[0102] 1 (1f, 1g, 1h, 1j, 1k, 1m, 20, 20f, 20g, 20h, 30, 30j, 30k, 30m) Mattress 1a First Mattress 1b Second mattress 1c Third Mattress 1d Fourth Mattress 1e Fifth Mattress 5, 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5j, 5p, 5q groove 10, 10a, 10b Mattress Unit 11, 21, 31 First layer 12, 12a, 12b, 22, 32 second layer 13, 23 Third layer 50 curves D1, D2, D3, D4 lines L1, L2, L3, L4, L5, L6, L7, L8 columns t1, t2, t3, t21, t22, t31, t32 Thickness

Claims

1. It comprises at least three layers of cushioning material, each having a predetermined thickness, consisting of a first layer, a second layer, and a third layer. In the thickness direction, the second layer is sandwiched and superimposed between the first layer and the third layer. The second layer has a lower rebound modulus than the first layer and the third layer. In the thickness direction, a groove is formed that penetrates the first layer but does not penetrate the third layer. The rebound modulus of the first and third layers is 40-50%. A mattress in which the rebound elasticity of the second layer is 18-25%.

2. It comprises at least three layers of cushioning material, each having a predetermined thickness, consisting of a first layer, a second layer, and a third layer. In the thickness direction, the second layer is sandwiched and superimposed between the first layer and the third layer. The second layer has a lower rebound modulus than the first layer and the third layer. Multiple inverted Y-shaped grooves are formed in a plan view from the surface of the first layer by grooves that penetrate the first layer in the thickness direction. Multiple triangles are formed by the aforementioned inverted Y-shaped groove. The aforementioned inverted Y-shaped groove is formed by the intersection of three straight grooves. The points where the three straight grooves intersect are connected by an arc-shaped curve. The aforementioned arc-shaped curve is formed as a convex ridge toward the center of the inverted Y-shaped groove, The rebound modulus of the first and third layers is 40-50%. A mattress in which the rebound elasticity of the second layer is 18-25%.

3. A cushioning material comprising at least three layers, a first layer, a second layer, and a third layer, each having a predetermined thickness, In the thickness direction, the second layer is sandwiched and superimposed between the first layer and the third layer. The second layer has a lower rebound modulus than the first layer and the third layer. In the thickness direction, a groove is formed that penetrates the first layer but does not penetrate the third layer. A mattress that satisfies the following A and / or B, In A, the density of the first layer and the third layer is 35 to 55 kg / m³, and the density of the second layer is 25 to 45 kg / m³. The above-mentioned B is a mattress in which the thickness of the first layer and the second layer is 10 to 30 mm, and the thickness of the third layer is 50 to 70 mm.

4. A cushioning material comprising at least three layers, a first layer, a second layer, and a third layer, each having a predetermined thickness, In the thickness direction, the second layer is sandwiched and superimposed between the first layer and the third layer. The second layer has a lower rebound modulus than the first layer and the third layer. Multiple inverted Y-shaped grooves are formed in a plan view from the surface of the first layer by grooves that penetrate the first layer in the thickness direction. Multiple triangles are formed by the aforementioned inverted Y-shaped groove. The aforementioned inverted Y-shaped groove is formed by the intersection of three straight grooves. The points where the three straight grooves intersect are connected by an arc-shaped curve. The aforementioned arc-shaped curve is formed as a convex ridge toward the center of the inverted Y-shaped groove, A mattress that satisfies the following A and / or B, The above A has a density of 35 to 55 kg / m³ for the first and third layers. ３ The density of the second layer is 25 to 45 kg / m³. ３ And, The above-mentioned B is a mattress in which the thickness of the first layer and the second layer is 10 to 30 mm, and the thickness of the third layer is 50 to 70 mm.

5. A cushioning material comprising at least two layers, a first layer and a second layer, each having a predetermined thickness, In the thickness direction, the first layer and the second layer are stacked on top of each other. The second layer has a lower rebound modulus than the first layer. In the thickness direction, a groove is formed in at least a portion of the second layer that penetrates the first layer and continues thereafter. The rebound modulus of the aforementioned first layer is 40-50%. A mattress in which the rebound elasticity of the second layer is 18-25%.

6. A cushioning material comprising at least two layers, a first layer and a second layer, each having a predetermined thickness, In the thickness direction, the first layer and the second layer are stacked on top of each other. The second layer has a greater air permeability than the first layer. In the thickness direction, a groove is formed that penetrates at least the aforementioned layer, The rebound modulus of the aforementioned first layer is 40-50%. A mattress in which the rebound elasticity of the second layer is 18-25%.

7. The mattress according to any one of claims 1 to 6, wherein the upper and lower surfaces of the first layer are flat.

8. A mattress unit comprising multiple mattresses arranged side by side according to any one of claims 1 to 7.

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