Mold, and foam body

Abstract

To provide a mold capable of reducing underfills regardless of a shape of an insert component, and a foam body.SOLUTION: A mold comprises: a first shaft that penetrates a first vent hole of the mold; an actuator that reciprocates the first shaft in the axial direction; a first valve disc provided on the first shaft; and a first protrusion that protrudes toward the side opposite to the first shaft with the first disc in between. The first valve disc opens / closes the first vent hole by reciprocating the first shaft, and a first insert component is fit to the first protrusion. In the foam body, a first hole provided on the first insert component and a second hole provided on a surface of the foam body communicate with each other on a same straight line.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vented mold and foam having an integrated insert. [Background technology]

[0002] In a molding die for a foam with an integrated insert part, the prior art disclosed in Patent Document 1 positions the insert part in the mold so that the air hole of the mold and the through hole of the insert part are not aligned in the same line, in order to reduce partial loss in the shape of the foam (hereinafter referred to as "underfill"). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-174627 A Summary of the Invention [Problem to be solved by the invention]

[0004] The prior art has a problem in that the insert parts that are integrated with the foam are limited to shapes that have through holes.

[0005] The present invention has been made to solve this problem, and has an object to provide a molding die and a foam that can reduce underfill regardless of the shape of the insert part. [Means for solving the problem]

[0006] A first aspect for achieving this object is a mold for a foam into which a first insert part is integrally molded, the mold comprising a first shaft penetrating a first vent hole of the mold, an actuator that reciprocates the first shaft in the axial direction, a first valve body provided on the first shaft, and a first protrusion that protrudes to the opposite side of the first shaft across the first valve body. The reciprocating motion of the first shaft causes the first valve body to open and close the first vent hole, and the first insert part is attached to the first protrusion.

[0007] The second aspect is the first aspect, further comprising a second protrusion provided in parallel with the first protrusion. The distance between the first protrusion and the second protrusion is shorter than the length of the first insert part, and the first insert part is fixed to the first protrusion and the second protrusion.

[0008] A third aspect is the second aspect, further comprising a second shaft penetrating a second vent hole of the mold provided alongside the first vent hole, and a second valve body provided on the second shaft. The actuator reciprocates the second shaft in the axial direction simultaneously with the first shaft, and the second valve body opens and closes the second vent hole due to the reciprocating movement of the second shaft. The second protrusion protrudes to the opposite side of the second shaft, sandwiching the second valve body therebetween.

[0009] In a fourth aspect, in the first aspect, a portion of the first protrusion to which the first insert part is attached has a non-circular cross-sectional shape.

[0010] The fifth aspect is a foam with a first insert part integrally molded therewith, in which a first hole in the first insert part and a second hole in the surface of the foam are connected in the same straight line.

[0011] In a sixth embodiment, in the fifth embodiment, the diameter of the second hole is larger than the diameter of the first hole.

[0012] A seventh aspect is the fifth or sixth aspect, further comprising a second insert piece disposed between the surface of the foam and the first insert piece. Effect of the Invention

[0013] According to the present invention, when the first valve body closes the first vent hole with a gap between the first insert part attached to the first protrusion and the molding die, the foam material enters between the first insert part and the molding die from between the first vent hole and the first valve body while discharging gas. Therefore, underfill of the foam can be reduced regardless of the shape of the insert part. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a cross-sectional view of a molding die according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of a mold and a foam. [Diagram 3] 3(a) is a cross-sectional view of a molding die in a second embodiment, (b) is a cross-sectional view of a first convex portion taken along line IIIb-IIIb in FIG. 3(a), and (c) and (d) are cross-sectional views of the first convex portion in modified examples. [Figure 4] FIG. 11 is a cross-sectional view of a molding die according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view of a molding die 10 in the first embodiment. Examples of the molding die 10 include one in which a cavity 11 is formed between an upper die and a lower die, and one in which a core is disposed and a cavity 11 is formed between an upper die and a lower die. In Fig. 1, a part of the upper die is shown as the molding die 10, and the core and lower die are omitted (the same applies to Figs. 2 to 4).

[0016] 2 is a cross-sectional view of a mold 10 and a foam 50 made of elastic synthetic resin molded by the mold 10. The foam 50 is integrated with a first insert part 40 and a second insert part 43. Applications of the foam 50 include, but are not limited to, seat pads for vehicles such as automobiles, trains, ships, and airplanes. Applications of the foam 50 are not limited.

[0017] The synthetic resin contained in the foam 50 is urethane. The urethane material is exemplified by one containing polyol, isocyanate, and water. In the cavity 11 of the mold 10, a resinification reaction between the polyol and isocyanate and a foaming reaction between the isocyanate and water proceed simultaneously to produce a soft polyurethane foam. The urethane material is initially in a low-viscosity liquid state, but as the reaction proceeds, it swells and increases in viscosity, and finally hardens.

[0018] A first vent hole 16 and a second vent hole 26 penetrating the mold 10 are provided in the mold 10 at a distance from each other. Gas generated during the reaction of the materials and air in the cavity 11 are exhausted to the outside of the mold 10 through the first vent hole 16 and the second vent hole 26. The mold 10 is equipped with a vent device 12 that opens and closes the first vent hole 16 and the second vent hole 26. Since a part of the upper mold is shown as the mold 10 in FIG. 1, the vent device 12 is arranged in the upper mold, but this is not limited to this. It is of course possible to arrange the vent device 12 in the core depending on the shape of the mold 10, etc.

[0019] The vent device 12 includes a first shaft 17 that passes through the first vent hole 16, an actuator 18 that reciprocates the first shaft 17 in the axial direction, and a first valve body 20 provided on the first shaft 17. An example of the actuator 18 is a cylinder. The first valve body 20 opens and closes the first vent hole 16 due to the reciprocating movement of the first shaft 17 by the actuator 18.

[0020] The first vent hole 16 and the second vent hole 26 are formed in a tube 14 that is disposed in a hole 13 that penetrates the mold 10. The tube 14 extends toward the outside of the mold 10. The size of the inner circumference of the tube 14 is constant over its entire length. The tube 14 is fixed to the mold 10 by a fixture 15 that is disposed on the outer periphery of the tube 14. An actuator 18 that is disposed at the end of the tube 14 is fixed to the tube 14 by a fixture 19.

[0021] The first valve body 20 enters the first vent hole 16 to close the first vent hole 16. When the first valve body 20 closes the first vent hole 16, a gap is formed between the first vent hole 16 and the first valve body 20 that allows gas to pass through. When the first vent hole 16 is to be opened, the first valve body 20 exits the first vent hole 16 and enters the cavity 11.

[0022] The first shaft 17 is provided with protrusions 21, 22 protruding outward from the shaft 17 between the first valve body 20 and the actuator 18. The first valve body 20 and the protrusions 21, 22 are arranged on the first shaft 17 with a gap between them in the axial direction. The axial length of the protrusions 21, 22 is longer than the axial length of the first valve body 20. When the first valve body 20 closes the first vent hole 16, the protrusions 21, 22 are located inside the first vent hole 16. The thickness of the protrusions 21, 22 is slightly smaller than the width of the first vent hole 16.

[0023] The first shaft 17 is provided with a first protrusion 23 that protrudes to the opposite side of the first shaft 17, sandwiching the first valve body 20 therebetween. The first protrusion 23 includes a first portion 24 and a second portion 25, in that order, from the first valve body 20, and extends on the same straight line as the first shaft 17. The first portion 24 has the same thickness as the first valve body 20, and the second portion 25 is thinner than the first portion 24.

[0024] The vent device 12 further includes a second shaft 27 that passes through the second vent hole 26, and a second valve body 28 provided on the second shaft 27. The second shaft 27 is disposed parallel to the first shaft 17. The actuator 18 reciprocates the second shaft 27 in the axial direction in synchronization with the reciprocating motion of the first shaft 17. The reciprocating motion of the second shaft 27 by the actuator 18 causes the second valve body 28 to open and close the second vent hole 26.

[0025] The second valve body 28 enters the second vent hole 26 to close the second vent hole 26. When the second valve body 28 closes the second vent hole 26, a gap is formed between the second vent hole 26 and the second valve body 28 that allows gas to pass through. When the second vent hole 26 is to be opened, the second valve body 28 exits the second vent hole 26 and enters the cavity 11.

[0026] The second shaft 27 is provided with protrusions 29, 30 protruding outward from the shaft 27 between the second valve body 28 and the actuator 18. The second valve body 28 and the protrusions 29, 30 are arranged on the second shaft 27 with an axial distance between them. The axial length of the protrusions 29, 30 is longer than the axial length of the second valve body 28. The shapes and sizes of the first valve body 20, the second valve body 28, and the protrusions 21, 22, 29, 30 are merely examples and are not limited thereto. When the second valve body 28 closes the second vent hole 26, the protrusions 29, 30 are located inside the second vent hole 26. The thickness of the protrusions 29, 30 is slightly smaller than the width of the second vent hole 26.

[0027] The second shaft 27 is provided with a second protrusion 31 that protrudes to the opposite side of the second shaft 27, sandwiching the second valve body 28. The second protrusion 31 includes a first portion 32 and a second portion 33, in that order, from the second valve body 28, and extends on the same straight line as the second shaft 27. The first portion 32 has the same thickness as the second valve body 28, and the second portion 33 is thinner than the first portion 32.

[0028] The first insert part 40 is attached to the first protrusion 23 and the second protrusion 31. The first insert part 40 is a block-shaped part embedded in the foam 50. Examples of the material of the first insert part 40 include a synthetic resin foam having an elastic deformation region and a plastic deformation region, such as polystyrene foam or polyethylene foam, which is made of a different material from the foam 50, a foam (soft foam) which is an elastic body formed of the same material as the foam 50, and a three-dimensional mesh structure which is an elastic body made of fibers. The three-dimensional mesh structure is obtained by solidifying and molding fibers by heat fusion or adhesion. There is no restriction on the hardness and air permeability of the first insert part 40 compared to the foam 50, or the shape and size of the first insert part 40, and these are appropriately set according to the hardness, shape, and application of the foam 50.

[0029] The first insert part 40 has first holes 41 and 42 into which the second part 25 of the first protrusion 23 and the second part 33 of the second protrusion 31 are fitted, respectively. The first holes 41 and 42 penetrate the first insert part 40. In this embodiment, the cross-sectional shapes of the second parts 25 and 33 and the first holes 41 and 42 are all circular, but this is not limited thereto, and these cross-sectional shapes can be set appropriately. When the second parts 25 and 33 are fitted into the first holes 41 and 42, respectively, the first holes 41 and 42 are blocked. The distance D between the center of the first protrusion 23 and the center of the second protrusion 31 is shorter than the length L of the first insert part 40. In this embodiment, the second parts 25 and 33 protrude from the first holes 41 and 42, respectively.

[0030] The first insert part 40 is attached to the first protrusion 23 and the second protrusion 31 by the interference between the first hole 41 and the second part 25, and the interference between the first hole 42 and the second part 33. The first insert part 40 attached at two points, the first protrusion 23 and the second protrusion 31, cannot rotate around the first protrusion 23 or the second protrusion 31. The first insert part 40 is fixed at two points, the first protrusion 23 and the second protrusion 31, which increases its stability.

[0031] Since the first portion 24 of the first protrusion 23 is thicker than the first hole 41, and the first portion 32 of the second protrusion 31 is thicker than the first hole 42, when the second portions 25, 33 are fitted into the first holes 41, 42 until the first insert part 40 comes into contact with the first portions 24, 32, the first insert part 40 is attached to the determined positions of the first protrusion 23 and the second protrusion 31. This allows the first insert part 40 to be positioned accurately in the mold 10. When the first valve body 20 closes the first vent hole 16 and the second valve body 28 closes the second vent hole 26, a space 44 is formed between the first insert part 40 and the mold 10, with the distance between the first insert part 40 and the mold 10 being approximately 5 mm to 60 mm. The distance of the space 44 is determined by the length of the first portions 24, 32.

[0032] In this embodiment, the second insert part 43 is disposed near the mold 10. The second insert part 43 is attached to a fixture (not shown) provided on the mold 10. The second insert part 43 is exemplified by a wire or frame made of synthetic resin or metal that reinforces the foam 50. The distance between the second insert part 43 and the mold 10 is shorter than the distance between the first insert part 40 and the mold 10. In addition to the first insert part 40 and the second insert part 43, a backing material (not shown) such as a nonwoven fabric may be attached to the mold 10 and integrated with the foam 50.

[0033] When the foam 50 is molded using the mold 10, as shown in FIG. 1, the second insert part 43 is placed in the mold 10, and the first insert part 40 is placed in the first convex part 23 and the second convex part 31. The material is injected into the lower mold (not shown), and the vent device 12 moves the material to the closing position of the first vent hole 16 and the second vent hole 26, and then the mold 10 is closed. The material reacted in the cavity 11 gradually becomes more viscous as it expands, and is filled into the cavity 11. The material enters the space 44 between the first insert part 40 and the mold 10 while discharging gas from between the first vent hole 16 and the first valve body 20 and between the second vent hole 26 and the second valve body 28. Since gas can be prevented from accumulating in the space 44, it is possible to reduce a partial loss (underfill) in the shape of the foam 50.

[0034] Even if there is no hole penetrating the first insert part 40 between the first hole 41 and the first hole 42, the material of the foam 50 flows around the first insert part 40 and smoothly enters the space 44, so that underfill of the foam 50 can be reduced regardless of the shape of the insert part 40. Since there is no limitation on the shape of the first insert part 40, a hole penetrating the first insert part 40 may be provided between the first hole 41 and the first hole 42.

[0035] In order to prevent gas from accumulating in space 44, gas is exhausted through the gap between the first air vent 16 and the first valve body 20 and the gap between the second air vent 26 and the second valve body 28. Therefore, even if the second insert part 43 is positioned at a position shorter than the distance between the first insert part 40 and the molding die 10, underfill of the foam 50 occurring around the second insert part 43 can be reduced.

[0036] A part of the material of the foam 50 may enter the first vent hole 16 or the second vent hole 26 together with the gas discharged from the gap between the first vent hole 16 and the first valve body 20 or the gap between the second vent hole 26 and the second valve body 28, causing burrs. The burrs mainly harden around the first valve body 20, between the first valve body 20 and the protruding portion 21, around the second valve body 28, and between the second valve body 28 and the protruding portion 29.

[0037] When removing the foam 50, as shown in Fig. 2, the mold 10 is opened, and the first vent hole 16 and the second vent hole 26 are opened by the vent device 12. When the first vent hole 16 and the second vent hole 26 are opened, the protrusions 21 and 22 pass through the first vent hole 16, and the protrusions 29 and 30 pass through the second vent hole 26, so that the burrs in the first vent hole 16 and the second vent hole 26 appear on the inside of the mold 10. Therefore, the burrs can be easily removed.

[0038] In the foam 50, a surface 51 is formed by a molding die 10 provided with a first vent hole 16 and a second vent hole 26, and a surface 52 is formed by a lower die. The distance between the surfaces 51 and 52 of the foam 50 is, for example, 70 mm or more. The foam 50 includes second holes 53, 54 opening into the surface 51. The second hole 53 is formed in the first portion 24 of the first convex portion 23, and the second hole 54 is formed in the first portion 32 of the second convex portion 31. In the foam 50, the first holes 41, 42 are blind holes.

[0039] The second hole 53 is connected to the first hole 41 of the first insert part 40 in the same straight line, and the second hole 54 is connected to the first hole 42 of the first insert part 40 in the same straight line. The width of the second hole 53 is larger than the width of the first hole 41, and the width of the second hole 54 is larger than the width of the first hole 42, so that the foam 50 can be easily removed from the vent device 12. Since the second holes 53 and 54 open on the surface 51 of the foam 50, the resistance of the foam 50 to bending and twisting is reduced by the amount of the holes 53 and 54. As a result, the foam 50 is more flexible than a foam without the second holes 53 and 54.

[0040] In addition, since there is a distance between the surface 51 of the foam 50 and the first insert part 40, and the first insert part 40 is embedded in the foam 50, the first insert part 40 does not come into direct contact with the frame when it is attached to the frame of a vehicle or the like. This reduces damage to the first insert part 40.

[0041] A second embodiment will be described with reference to Fig. 3. In the first embodiment, a case where a first insert part 40 is attached and fixed to two protrusions 23, 31 will be described. In the second embodiment, a case where a first insert part 65 is attached and fixed to one protrusion 62 will be described. In the second embodiment, the same parts as those described in the first embodiment are given the same reference numerals, and the following description will be omitted.

[0042] FIG. 3(a) is a cross-sectional view of a molding die 60 in the second embodiment. The molding die 60 is provided with a vent device 61 that opens and closes the first vent hole 16. The first shaft 17 of the vent device 61 is provided with a first protrusion 62 that protrudes to the opposite side of the first shaft 17, sandwiching the first valve body 20. The first protrusion 62 extends on the same straight line as the first shaft 17, and includes a first part 24 and a second part 63 in this order from the first valve body 20. The second part 63 is thinner than the first part 24. A protrusion 64 is provided on the side of the second part 63, extending along the axial direction of the second part 63. The second part 63 is fitted into a first hole 66, which is a blind hole, provided in the first insert part 65, and the first insert part 65 is placed inside the molding die 60.

[0043] FIG. 3(b) is a cross-sectional view of the first protrusion 62 taken along line IIIb-IIIb in FIG. 3(a). The second part 63 includes a protrusion 64 provided on the side of a rod having a circular cross section, and is disposed in a first hole 66 having a circular cross section. If the deformation of the first hole 66 caused by the protrusion 64 is in the plastic deformation region of the first insert part 65, the protrusion 64 bites into the first hole 66, and if it is in the elastic deformation region of the first insert part 65, the first hole 66 is deformed into an elliptical shape. This prevents the first insert part 65 from falling and rotating around the first protrusion 62. Since the second part 63 has a non-circular cross section, the first insert part 65 can be fixed at a predetermined position in the mold 60.

[0044] 3(c) and 3(d) are cross-sectional views of second parts 67, 69 in modified examples of the first protrusion 62. As shown in Fig. 3(c), the second part 67 includes a protrusion 68 provided on the side of a rod having an elliptical cross section. The non-circular second part 67 including the protrusion 68 deforms the first hole 66 of the first insert part 65, so that the first insert part 65 can be prevented from falling and rotating around the first protrusion 62.

[0045] 3(d), the second portion 69 includes a plurality of protrusions 70 provided on the side of a rod having a circular cross section. The non-circular second portion 69 including the protrusions 70 deforms the first hole 66 of the first insert part 65, preventing the first insert part 65 from dropping and rotating around the first protrusion 62. This allows the first insert part 65 to be fixed at a predetermined position in the molding die 60.

[0046] The third embodiment will be described with reference to Fig. 4. In the first embodiment, the two protrusions 23, 31 to which the first insert part 40 is attached are moved synchronously by the actuator 18. In the third embodiment, a case will be described in which of the two protrusions 23, 82 to which the first insert part 83 is attached, the protrusion 23 moves, but the protrusion 82 is fixed. In the third embodiment, the same parts as those described in the first embodiment are given the same reference numerals, and the following description will be omitted.

[0047] FIG. 4 is a cross-sectional view of a molding die 80 in the third embodiment. The molding die 80 is provided with a vent device 81 that opens and closes the first vent hole 16. The vent device 81 includes a first shaft 17 that penetrates the first vent hole 16, an actuator 18 that reciprocates in the axial direction of the first shaft 17, a first valve body 20 provided on the first shaft 17, and a first protrusion 23 that protrudes to the opposite side of the first shaft 17 across the first valve body 20. A second protrusion 82 is arranged on the molding die 80 in parallel with the first shaft 17 and protrudes toward the inside of the molding die 80. The second protrusion 82 is fixed to the molding die 80.

[0048] The first insert part 83 is provided with a first hole 41 into which the first protrusion 23 fits and a first hole 84 into which the second protrusion 82 fits. Since the first hole 84 is smaller than the thickness of the second part 25, it is possible to prevent the second part 25 from being erroneously fitted into the first hole 84.

[0049] The first hole 84 is larger than the thickness of the second protrusion 82. The second protrusion 82 is set to a length that fits into the first hole 84 of the first insert part 83 attached to the first protrusion 23 when the vent device 81 closes the first vent hole 16. The distance D between the center of the first protrusion 23 and the center of the second protrusion 82 is shorter than the length L of the first insert part 83. When the vent device 81 closes the first vent hole 16, the second protrusion 82 fits into the first hole 84 of the first insert part 83 attached to the first protrusion 23, so that the first insert part 83 cannot rotate around the first protrusion 23. Therefore, the first insert part 83 is stably fixed to the mold 80.

[0050] The present invention has been described above based on an embodiment, but the present invention is not limited to the above embodiment, and it can be easily imagined that various improvements and modifications are possible within the scope of the present invention without departing from the spirit of the present invention.

[0051] In the embodiment, the case where the protrusions 23, 31, 62, 82 are fitted into the holes 41, 42, 66, 84 provided in advance in the insert parts 40, 65, 83 to fix the insert parts 40, 65, 83 is described, but this is not necessarily limited to this. It is of course possible to make the tip of the protrusion 23, 31, 62, 82 sharp and stick it into a specified position to fix the insert parts 40, 65, 83 without providing the holes 41, 42, 66, 84. It is also possible to provide a magnet on the protrusion 23, 31, 62, 82 or to make the protrusion 23, 31, 62, 82 from a magnet, and attract a ferromagnetic member attached to a specified position of the insert part 40, 65, 83 to fix the insert parts 40, 65, 83.

[0052] In the first and third embodiments, the insert parts 40, 83 are fixed using the first and second protrusions, but this is not necessarily limited to this. If the insert parts 40, 83 are large or have a complex shape, it is of course possible to fix the insert parts 40, 83 using three or more protrusions.

[0053] In the second embodiment, the second parts 63, 67, 69 of the protrusion 62 include the protrusions 64, 68, 70 provided on the side of a rod having a circular or elliptical cross section, but this is not necessarily limited to this. It is of course possible to make the cross-sectional shape of the second parts 63, 67, 69 polygonal, such as triangular or rectangular. By making the cross-sectional shape of the second parts 63, 67, 69 and the shape of the hole 66 into which the second parts 63, 67, 69 are fitted polygonal (non-circular), it is possible to prevent the insert part 65 from rotating around the protrusion 62 and to prevent the insert part 65 from being erroneously attached or falling off.

[0054] In the embodiment, the first portion 24, 32 is thicker than the second portion 25, 33, 63, but this is not necessarily limited to this. It is of course possible to make the thickness of the first portion 24, 32 the same as that of the second portion 25, 33, 63, or to make the thickness gradually increase from the tip of the second portion 25, 33, 63 to the first portion 24, 32 in a tapered shape. [Explanation of symbols]

[0055] 10,60,80 mold 16 First Vent 17 First axis 18 Actuators 20 First valve body 23,62 First protrusion 26 Second Vent 27 Second Axis 28 Second valve body 31 Second protrusion 40,65,83 First insert part 41,42,66,84 First hole 43 Second insert part 50 Foam 51 Surface 53,54 Second hole

Claims

1. A foam mold into which a first insert is molded, comprising: a first shaft passing through a first vent hole of the mold; an actuator that reciprocates the first shaft in an axial direction; a first valve body provided on the first shaft; a first protrusion protruding to an opposite side of the first shaft across the first valve body, The first valve body opens and closes the first vent hole by the reciprocating movement of the first shaft, A molding die in which the first insert part is attached to the first protrusion.

2. a second protrusion provided alongside the first protrusion, The distance between the first protrusion and the second protrusion is shorter than the length of the first insert part, The mold according to claim 1 , wherein the first insert part is fixed to the first protrusion and the second protrusion.

3. a second shaft passing through a second vent hole of the mold provided next to the first vent hole; a second valve body provided on the second shaft, The actuator reciprocates the second shaft in an axial direction, The second valve body opens and closes the second vent hole by the reciprocating movement of the second shaft, The molding die according to claim 2 , wherein the second protrusion projects to a side opposite the second shaft with the second valve body therebetween.

4. 2. The mold according to claim 1, wherein the portion of the first protrusion to which the first insert part is attached has a non-circular cross-sectional shape.

5. the first insert is an integrally molded foam; a first hole provided in the first insert piece; A foam body in which the second hole and a second hole provided on the surface of the foam body are connected in the same straight line.

6. 6. The foam of claim 5, wherein the second hole has a diameter greater than the diameter of the first hole.

7. 7. The foam of claim 5 or 6, further comprising a second insert disposed between the surface of the foam and the first insert.

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