Cotton fasteners and forming devices

Abstract

In the surface fastener (1) of the present invention, each engaging element (20) has a stem portion (21) and a hook portion (30) having a first hook portion (31) and a second hook portion (32), the first hook portion (31) and the second hook portion (32) have an upper curved surface (33a) in the shape of an arc, and an arc-shaped groove portion (36) is provided between the first hook portion (31) and the second hook portion (32), and an upper inclined line (Lu) is defined connecting the center of the arc of the upper curved surface (33a) and the center of the arc of the groove portion (36), the circumference including the upper curved surface (33a) is defined as the hook circumference (P), and a straight line passing through the center of the arc of the groove portion (36) is defined as the reference perpendicular (Lv), and regarding the reference perpendicular (Lv) The angle of inclination (θ) of the upper inclined line (Lu) is 55° or greater and 90° or less, and the hook circumference (P) is tangent to the reference perpendicular (Lv) at one point or intersects at two points. Accordingly, it is difficult to cause deformation in the hook portion (30) during the molding of the coupling element (20).

Description

Technology Field

[0001] The present invention relates to a face fastener and a molding device for forming a face fastener. Background Technology

[0002] Conventionally, a face fastener product is known in which a loop member having multiple loops (female face fastener) and a face fastener having multiple hook-shaped engaging elements detachable from the loop member (male face fastener) are combined.

[0003] Representative forms of hook-shaped coupling elements include palm tree-shaped, J-shaped, and mushroom-shaped forms.

[0004] For example, a palm tree-type engaging element has a shape comprising a stem portion protruding from a base portion and a hook portion (also called a hook head portion) that branches out and extends in two directions opposite to each other from the upper portion of the stem portion. In addition, a face fastener having a palm tree-type engaging element is described, for example, in U.S. Patent No. 7520033 (Patent Document 1). Prior art literature

[0005] U.S. Patent No. 7520033 The problem to be solved

[0006] As one method for manufacturing a face fastener having a hook-shaped engaging element, a method of continuously molding a synthetic resin using a die wheel is known. In this method, the die wheel is arranged to rotate continuously in one direction (e.g., the machine direction), and a plurality of cavity spaces corresponding to the shape of the engaging element are formed on the outer periphery of the die wheel.

[0007] When manufacturing a face fastener having, for example, a palm tree-shaped engagement element using such a die wheel, the cavity space formed on the outer periphery of the die wheel has the same or similar shape as the engagement element. Accordingly, the cavity space of each engagement element is provided with a space extending toward the rotational direction of the die wheel and a space extending toward the opposite direction of the rotational direction of the die wheel, corresponding to the shape of the hook portions extending in opposite directions of the palm tree-shaped engagement element. Furthermore, regarding each cavity space provided in the die wheel, the space extending toward the rotational direction of the die wheel is referred to as the reverse drawing space, and the space extending toward the opposite direction of the rotation is referred to as the forward drawing space.

[0008] Accordingly, by supplying molten synthetic resin toward the die wheel as described above, the base portion of the face fastener can be formed on the outer surface of the die wheel, and at the same time, the coupling element can be formed integrally with the base portion within each cavity space of the die wheel.

[0009] In addition, as described above, when forming a mating element in each cavity space of the die wheel, when the face fastener formed by the die wheel is detached from the die wheel while continuously rotating the die wheel, a portion of the hook portion of the mating element can be drawn relatively smoothly from the drawing space in the cavity space of the die wheel.

[0010] Meanwhile, when drawing a part of the hook portion of the mating element from the reverse drawing space in the cavity space, that part of the hook portion gets caught on the die wheel. Because of this, the part of the hook portion caught on the die wheel is forcibly drawn by pulling the face fastener strongly from the die wheel.

[0011] However, due to the excessive pulling of the hook portion against the reverse pulling space as described above, deformation is likely to occur in the portion being pulled out from the reverse pulling space of the hook portion. Consequently, in each coupling element after forming, a difference in coupling strength with respect to the loop of the loop member occurs between the portion formed in the reverse pulling space of the hook portion and the portion formed in the forward pulling space, and as a result, a decrease in the coupling strength of each coupling element was caused.

[0012] In addition, due to the excessive drawing described above, the part formed in the reverse drawing space of the hook and the part formed in the forward drawing space are formed in an asymmetrical shape, so the balance of the shape of the mating element is poor, which lowers the appearance quality of the face fastener, and there were problems such as lowering the feel and tactile sensation when touching the face fastener from the mating element side.

[0013] The present invention has been made in consideration of the problem described above, and its purpose is to provide a face fastener having a engaging element that makes it difficult to cause deformation of the hook portion when drawing from a die wheel, and to provide a forming apparatus capable of forming such a face fastener. means of solving the problem

[0014] To achieve the above objective, the surface fastener of the present invention comprises a flat base portion and a plurality of engaging elements provided on the upper surface of the base portion, wherein each engaging element comprises a stem portion extending from the base portion and a hook portion extending in a curved manner, branching into two from the upper end of the stem portion, wherein the hook portion comprises a first hook portion extending toward one side in the longitudinal direction of the base portion and a second hook portion extending toward the other side in the longitudinal direction, wherein, when the engaging element is viewed from the side view of the engaging element in the width direction of the base portion or in a cross-sectional view perpendicular to the width direction of the engaging element, the first hook portion and the second hook portion each have an upper curved surface formed as an arc-shaped convex surface while forming at least a portion of the upper surface of the hook portion, and an arc-shaped valley portion is provided between the first hook portion and the second hook portion, and when the engaging element is viewed from the side view Alternatively, in the above cross-section, a virtual straight line connecting the center of the arc formed by the upper curved surface and the center of the arc formed by the groove is defined as the upper inclined line, a circumference including the arc formed by the upper curved surface is defined as the hook circumference, a virtual straight line passing through the center of the arc formed by the groove and parallel to the height direction of the joining element is defined as the reference perpendicular, and the angle of inclination of the upper inclined line with respect to the reference perpendicular is 55° or greater and 90° or less, and the hook circumference is a surface fastener that is tangent to the reference perpendicular at one point or intersects at two points.

[0015] In this case, when the above-mentioned side view or above-mentioned cross-section of the above-mentioned coupling element, the first hook portion and the second hook portion each have a lower curved surface formed as an arc-shaped concave surface while forming at least a part of the lower surface of the hook portion, and a virtual straight line connecting the center of the arc formed by the lower curved surface and the center of the arc formed by the groove portion is defined as a lower inclined line, and it is preferable that the upper inclined line and the lower inclined line are placed on the same straight line, or that the angle between the upper inclined line and the lower inclined line is 2° or less.

[0016] In the surface fastener of the present invention, the inclination angle of the upper inclined line is preferably 60°.

[0017] In addition, when viewing the coupling element from the length direction, the front or back view of the coupling element, it is preferable that the upper surface of the first hook portion and the second hook portion be formed as a curved surface that curves upward in a convex shape, or as a flat plane parallel to the width direction.

[0018] In addition, in the side view or cross view of the above-mentioned coupling element, it is preferable that the upper curved surface having an arc shape be provided continuously over a range of at least 50% of the upper surface of the hook portion.

[0019] Furthermore, according to the present invention, a molding apparatus for forming a surface fastener along a machine direction comprises a flat base portion and a plurality of engaging elements provided on the upper surface of the base portion, wherein each engaging element has a stem portion extending from the base portion and a hook portion branching into two from the upper end of the stem portion and extending while curving, wherein the hook portion has a first hook portion extending toward one side in the longitudinal direction of the base portion and a second hook portion extending toward the other side in the longitudinal direction, the molding apparatus comprises a mold having a cavity space for forming one of the engaging elements, wherein the cavity space, in a cross-section perpendicular to the orthogonal direction of the molding apparatus, has a first hook forming portion for forming the first hook portion, a second hook forming portion for forming the second hook portion, and a central protrusion having an arc-shaped tip surface while forming a groove between the first hook portion and the second hook portion, and the first hook forming portion and the second A forming device is provided in which a hook forming section has an upper curved forming surface formed as an arc-shaped concave surface, which forms at least a portion of the upper surface of the hook section in the cross-section of the forming device, and in the cross-section of the forming device, a virtual straight line connecting the center of the arc formed by the upper curved forming surface and the center of the arc formed by the front end surface of the central protrusion is defined as an upper forming inclined line, a circumference including the arc formed by the upper curved forming surface is defined as a cavity circumference, a virtual straight line passing through the center of the arc formed by the front end surface of the central protrusion and parallel to the height direction of the engaging element is defined as a reference perpendicular line, and the angle of inclination of the upper forming inclined line with respect to the reference perpendicular line is 55° or greater and 90° or less, and the cavity circumference is tangent to the reference perpendicular line at one point or intersects at two points.

[0020] In this case, in the cross-section of the molding device, the first hook molding part and the second hook molding part each have a lower curved molding surface formed as an arc-shaped convex surface while forming at least a part of the lower surface of the hook part, and a virtual straight line connecting the center of the arc formed by the lower curved molding surface and the center of the arc formed by the front end surface of the central protrusion is defined as the lower molding inclined line, and it is preferable that the upper molding inclined line and the lower molding inclined line are placed on the same straight line, or that the angle between the upper molding inclined line and the lower molding inclined line is 2° or less.

[0021] In the molding apparatus of the present invention, the inclination angle of the upper molding inclined line is preferably 60°. Effects of the invention

[0022] According to the face fastener of the present invention, since the shape of each engaging element satisfies the aforementioned predetermined conditions, it is difficult to cause deformation in the hook portion of the engaging element when drawing from the die wheel during the forming of the face fastener by the die wheel. For this reason, it is difficult to cause a difference in the engaging strength with respect to the loop between the one-sided portion and the other-sided portion of the hook portion of the engaging element. Furthermore, according to the forming apparatus of the present invention, it is difficult to cause deformation in the hook portion of the engaging element when drawing from the die wheel, thereby enabling the forming of the face fastener. Brief explanation of the drawing

[0023] FIG. 1 is a cross-sectional view schematically showing a part of a face fastener related to an embodiment of the present invention. Figure 2 is an enlarged view schematically showing a portion of the coupling element shown in Figure 1. Figure 3 is a schematic diagram showing a manufacturing apparatus for manufacturing the face fastener shown in Figure 1. Figure 4 is an explanatory diagram schematically illustrating the deformation of the engaging element when drawing a face fastener from a die wheel. Specific details for implementing the invention

[0024] The inventors have conducted multifaceted research and examination from various angles regarding the shape of a joining element that makes it difficult to cause deformation (plastic deformation) in the hook portion of the joining element when drawing the joining element from the die wheel when forming a face fastener having a plurality of palm tree-shaped joining elements using a die wheel, taking into account the ease of drawing the joining element from the die wheel, the load applied to the joining element, the deformation of the joining element, and the joining state and joining strength when a loop is joined to the joining element after drawing.

[0025] As a result, regarding the shape of a palm tree-shaped engagement element, when the upper inclined line, hook circumference, and reference waterline are defined as described below, it became clear that the inclination angle (θ) of the upper inclined line relative to the reference waterline and the positional relationship of the hook circumference relative to the reference waterline affect the magnitude of the load applied to the engagement element when drawing the engagement element from the die wheel and the engagement strength of the loop of the engagement element. Furthermore, it became clear that the conditions described above, namely the inclination angle (θ) of the upper inclined line and the position of the hook circumference relative to the reference waterline, have the same effect when forming palm tree-shaped engagement elements of various sizes.

[0026] In addition, the inventors of the present invention have developed the present invention by appropriately setting both the angle of inclination (θ) of the upper inclined line relative to the reference perpendicular of the engaging element and the position of the hook circumference relative to the reference perpendicular, thereby making it difficult to cause deformation in the hook portion of the engaging element when drawing the palm tree-shaped engaging element from the die wheel, and also improving the engaging strength of the engaging element relative to the loop.

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0028] FIG. 1 is a cross-sectional view schematically showing a part of the surface fastener (1) related to the present embodiment. FIG. 2 is an enlarged view schematically showing a part of the engaging element (20) enlarged.

[0029] Additionally, in the following description, the front-rear direction is the direction along the length direction of the surface fastener (1) and the base part (10), or the direction along the machine direction (MD) in which the surface fastener (1) is conveyed during the manufacturing process of the surface fastener (1).

[0030] The left-right direction is orthogonal to the front-rear direction and also refers to the width direction along the upper surface (first surface) or lower surface (second surface) of the base portion (10) of the surface fastener (1). In addition, the left-right direction and the width direction are directions along the orthogonal direction (CD) which is orthogonal to the machine direction (MD).

[0031] The vertical direction is the height direction (or the thickness direction of the base part (10)) following a direction orthogonal to the upper or lower surface of the base part (10), and is also a direction orthogonal to the front-rear direction and the left-right direction. Furthermore, regarding the vertical direction, the direction on which the engaging element (20) protrudes relative to the base part (10) is designated as the upper side, and the opposite direction is designated as the lower side.

[0032] The cotton fastener (1) of the present embodiment is manufactured by molding a synthetic resin having thermoplastic properties using the manufacturing device (50) shown in FIG. 3. The cotton fastener (1) is manufactured in the shape of a long rod that is thin and long in the machine direction (MD) of the manufacturing device (50) when the cotton fastener (1) is in a flat state. In addition, in the present invention, the material of the cotton fastener (1) is not particularly limited. For the material of the cotton fastener (1), thermoplastic resins such as polypropylene, polyester, nylon, polybutylene terephthalate, or copolymers thereof may be used.

[0033] The surface fastener (1) has a thin flat plate-shaped base portion (10) and a plurality of engaging elements (20) integrally formed on the upper surface of the base portion (10). The upper and lower surfaces of the base portion (10) are formed to be flat and parallel to each other. The base portion (10) has a constant thickness capable of securing appropriate strength for the use of the surface fastener (1).

[0034] A plurality of connecting elements (20) are formed with the same shape and the same size. Each connecting element (20) has a palm tree shape and is formed in a shape close to a Y when viewed from the side (Fig. 1) in the width direction of the surface fastener (1). Each connecting element (20) has a shape that is symmetrical in the front and back directions with respect to the center line in the front and back direction of the connecting element (20).

[0035] A plurality of connecting elements (20) are arranged regularly in the length direction and width direction of the base portion (10). In addition, in the present invention, the arrangement of the connecting elements (20) is not particularly limited, and the plurality of connecting elements (20) may be arranged in a grid shape aligned along the length direction and width direction, for example, in the base portion (10), in a zigzag shape arranged alternately between two rows of connecting elements (20) along the length direction, or in a random arrangement.

[0036] Each connecting element (20) has a stem portion (21) extending upward from the base portion (10), and a hook portion (30) that branches into two forward and backward directions from the upper part of the stem portion (21) and extends while bending. The hook portion (30) of each coupling element (20) has, in a side view of the surface fastener (1) (Fig. 1) or a cross-sectional view orthogonal to the left and right directions of the coupling element (20) (not shown), a first hook portion (31) extending from the upper end of the stem portion (21) toward one side in the front-rear direction (e.g., upstream or rear side of the machine direction (MD)), a second hook portion (32) extending from the upper end of the stem portion (21) toward the other side in the front-rear direction (e.g., downstream or front side of the machine direction (MD)), and a groove portion (36) disposed between the first hook portion (31) and the second hook portion (32).

[0037] The stem portion (21) exhibits a roughly elliptical or roughly oblong shape, in which the dimension in the front-rear direction (length dimension) is larger than the dimension in the left-right direction (width dimension) when viewed in a cross-section perpendicular to the vertical direction of the stem portion (21). Additionally, the stem portion (21) has a shape in which the area of ​​the cross-section perpendicular to the vertical direction of the stem portion (21) gradually decreases toward the upward direction away from the base portion (10).

[0038] The stem portion (21) has a front end portion facing forward and a rear end portion facing backward when viewed from the side of the surface fastener (1). The front end portion and the rear end portion of the stem portion (21) have a straight portion formed in a straight or approximately straight manner and a curved portion that is bent in a concave shape and is positioned at the lower end connected to the base portion (10) of the stem portion (21).

[0039] The hook portion (30) is formed by extending upward from the upper portion of the stem portion (21) and being separated into two parts, front and rear. In this embodiment, when viewed from the side of the face fastener (1), the height position where the length dimension of the engaging element (20) changes from an increasing portion toward the top to a decreasing portion becomes the boundary between the stem portion (21) and the hook portion (30) of the engaging element (20).

[0040] The first hook portion (31) on the rear side and the second hook portion (32) on the front side of the hook portion (30) are formed in a shape that is symmetrical to each other in the front and rear directions. For this reason, the first hook portion (31) is mainly described here, and the description of the part of the second hook portion (32) that is similar to the first hook portion (31) is omitted.

[0041] In the side view of the surface fastener (1) (Fig. 1) or in the cross-sectional view perpendicular to the left and right directions of the coupling element (20) (particularly in the cross-sectional view in the center of the left and right directions of the coupling element (20)), the first hook portion (31) of the hook portion (30) has a shape that curves toward the rear. In addition, the first hook portion (31) has a hook upper surface (33) in the shape of a convex surface protruding toward the upper side, a hook lower surface (34) in the shape of a concave surface that is recessed toward the upper side and is positioned opposite to the hook upper surface (33) in the first hook portion (31), and a hook tip surface (35) formed extending from the hook upper surface (33) to the hook lower surface (34).

[0042] In this embodiment, the hook upper surface (33) of the first hook portion (31) is a visible surface of the first hook portion (31) when the surface fastener (1) is viewed from the upper side. The hook upper surface (33) is formed as a surface that curves upwardly in a convex shape when viewed from the side (Fig. 1) of the surface fastener (1) or the cross-sectional view of the coupling element (20), and also has an upper curved surface (upper arc surface) (33a) formed in the shape of an arc. In this embodiment, the arc-shaped upper curved surface (33a) is formed over a formation range of at least 50%, preferably at least 75%, and more preferably at least 90% of the hook upper surface (33) of the first hook portion (31).

[0043] In addition, the hook upper surface (33) of the first hook portion (31) is formed as a curved surface that curves upward in a ridge shape with respect to the left and right directions so that the central part of the left and right direction of the first hook portion (31) protrudes most towards the upper side when viewed from the back (Fig. 2) or front of the coupling element (20).

[0044] The hook surface (34) of the first hook portion (31) is formed as a surface that curves upward in a concave shape, positioned to face the base portion (10) in the side view of the face fastener (1) or the cross-section of the coupling element (20). Additionally, the hook surface (34) has a lower curved surface (lower arc surface) (34a) formed in the shape of an arc in the side view or the cross-section. In this embodiment, the arc-shaped lower curved surface (34a) is formed over a formation range of at least 50%, preferably at least 75%, and more preferably at least 90% of the hook surface (34) of the first hook portion (31).

[0045] The hook tip surface (35) of the first hook portion (31) is formed in a shape that curves downward in a convex shape with respect to the front and rear directions, and is positioned to face the base portion (10) when viewed from the side (Fig. 1) of the surface fastener (1). Additionally, the hook tip surface (35) is formed in a curved surface that curves downward in a ridge shape with respect to the left and right directions so that the central part in the left and right directions of the hook tip protrudes most toward the lower side when viewed from the back (Fig. 2) of the coupling element (20). Additionally, the hook tip surface (35) is formed in a curved surface that curves backward in a ridge shape with respect to the width direction so that the central part in the width direction of the hook tip protrudes most toward the rear when viewed from the top (not shown) of the coupling element (20).

[0046] In the first hook portion (31) of the present embodiment, as described above, the hook upper surface (33) is formed as a curved surface that curves upward in a ridge shape, and the hook front surface (35) is also formed as a curved surface that curves downward and backward in a ridge shape. Accordingly, when the engagement and separation between the surface fastener (1) and the loop member of the present embodiment are repeated, the engagement element (20) of the surface fastener (1) can prevent the loop of the loop member from being broken or damaged. Because of this, it becomes possible to use the product equipped with the surface fastener (1) and the loop member of the present embodiment for a longer period.

[0047] The groove (36) of the hook portion (30) is formed by a curved surface that is concave downward between the first hook portion (31) and the second hook portion (32) when viewed from the side (Fig. 1) of the face fastener (1). The curved surface forming the groove (36) is formed continuously on the hook upper surface (33) of the first hook portion (31) and the hook upper surface (33) of the second hook portion (32). In this embodiment, the curved surface forming the groove (36) is formed in the shape of an arc when viewed from the side.

[0048] Here, regarding the coupling element (20) of the present embodiment, in the side view of the surface fastener (1) (Fig. 1) or the cross-sectional view of the coupling element (20), the circumference including the arc formed by the upper curved surface (33a) of the first hook portion (31) is defined as the hook circumference (P), and the center of the arc formed by the upper curved surface (33a) is defined as the first center (Cu). The center of the arc formed by the lower curved surface (34a) of the first hook portion (31) is defined as the second center (Cd). The center of the arc formed by the curved surface of the groove portion (36) is defined as the third center (Cv).

[0049] In addition, a fictitious straight line extending to connect the first center (Cu) and the third center (Cv) is defined as the upper slope line (Lu), and a fictitious straight line extending to connect the second center (Cd) and the third center (Cv) is defined as the lower slope line (Ld). A fictitious straight line extending parallel to the upper and lower directions while passing through the third center (Cv) is defined as the reference perpendicular line (Lv).

[0050] Additionally, in the side view of the face fastener (1) (Fig. 1) or the cross-section of the coupling element (20), the length dimension of the stem portion (21) at the position where the length dimension (dimension in the front-rear direction) of the coupling element (20) is smallest (position of the boundary portion of the coupling element (20)) is defined as the minimum length dimension A. The dimension from the hook upper surface (33) to the hook lower surface (34) of the hook portion (30) on the upper inclined line (Lu) described above is defined as the maximum thickness B of the hook portion (30).

[0051] When the above-described regulations are applied, the coupling element (20) of this embodiment has an inclination angle (θ) of the upper inclined line (Lu) with respect to the reference perpendicular (Lv) of 55° or more and 90° or less, and also has a shape in which the hook circumference (P) touches the reference perpendicular (Lv) at one point or intersects at two points.

[0052] In the palm tree-shaped coupling element (20) shown in FIG. 1, the angle of inclination (θ) of the upper inclined line (Lu) with respect to the reference perpendicular line (Lv) is 55° or greater, so that the force (extraction force) required to pull the coupling element (20) out of the cavity space (65) of the die wheel (61) can be reduced, making it difficult to cause plastic deformation in the hook portion (30) of the coupling element (20). In addition, the angle of inclination (θ) of the upper inclined line (Lu) with respect to the reference perpendicular line (Lv) is 90° or less, so that the coupling element (20) can stably have a palm tree-shaped shape capable of connecting a loop.

[0053] In addition, the coupling element (20) is formed such that the hook circumference (P) touches the reference perpendicular (Lv) at one point or intersects it at two points. When the hook portion (30) of the coupling element (20) is hooked onto the hook portion (30) and receives a force pulling upward from the loop, it is easier to maintain the shape of the hook portion (30), making it difficult to plastically deform the hook portion (30). As a result, the coupling strength of the coupling element (20) with respect to the loop can be increased.

[0054] In this case, the fact that the hook circumference (P) is tangent to the reference perpendicular (Lv) at one point can be rephrased as the hook circumference (P) being positively tangent to the reference perpendicular (Lv). Additionally, the shape of the engaging element (20) in which the hook circumference (P) is tangent to the reference perpendicular (Lv) at one point or intersects at two points can be described as a shape in which the value of “A / 2B,” which is the ratio of the minimum length dimension A to twice the size of the maximum thickness B of the hook portion (30), is 1.0 or less.

[0055] In particular, the engaging element (20) has a shape in which the angle of inclination (θ) of the upper inclined line (Lu) with respect to the reference perpendicular line (Lv) is 59° or more and 65° or less, preferably 60°, and the value of "A / 2B" is 1.0 or less, thereby having a good balance of the effect of reducing the pulling force for drawing the engaging element (20) from the die wheel (61) and the effect of increasing the engaging strength of the engaging element (20) with respect to the loop.

[0056] In addition, the coupling element (20) of the present embodiment has a shape in which the upper inclined line (Lu) and the lower inclined line (Ld) are arranged on the same straight line, or the angle between the upper inclined line (Lu) and the lower inclined line (Ld) is 2° or less. In this case, it is preferable that the upper inclined line (Lu) and the lower inclined line (Ld) are arranged on the same straight line.

[0057] In this way, the upper inclined line (Lu) and the lower inclined line (Ld) are arranged on the same straight line or on approximately the same straight line where the angle between the two lines (Lu, Ld) is 2° or less, so that when the engaging element (20) is drawn out from the cavity space (65) of the die wheel (61), it is more difficult to plastically deform the hook portion (30) of the engaging element (20).

[0058] Next, a manufacturing apparatus (50) for manufacturing the surface fastener (1) of the above-described embodiment will be explained with reference to FIG. 3.

[0059] The manufacturing device (50) used in the present embodiment has a molding device (60) for molding a cotton fastener (1), a pickup roller (70) for peeling off the cotton fastener (1) from the molding device (60), and a cutting device (not shown) positioned downstream of the pickup roller (70).

[0060] The molding device (60) has a die wheel (61) that rotates in one direction and a nozzle part (62) positioned opposite the outer surface of the die wheel (61). The die wheel (61) has a wheel part (61a) that serves as a mold and a rotary drive roller (61b) that rotates the wheel part (61a) in one direction at a predetermined speed.

[0061] The wheel portion (61a) is formed into a cylindrical shape with a cut-out center by stacking multiple donut-shaped ring plates (mold plates) having a required thickness in an orthogonal direction (CD) or in the direction of the rotation axis of the die wheel (61).

[0062] In the outer circumference of the wheel portion (61a), a plurality of cavity spaces (65) capable of forming each coupling element (20) of the surface fastener (1) are provided. In this case, each cavity space (65) is provided in the outer circumference of the wheel portion (61a) in correspondence with the shape of the coupling element (20) to be formed. That is, in this embodiment, the cavity space (65) for forming one coupling element (20) is formed in the same shape as the palm tree-shaped coupling element (20) shown in FIGS. 1 and FIGS. 2.

[0063] In the die wheel (61) of the present embodiment, a cooling jacket (not shown) is provided to circulate a cooling liquid within a rotary drive roller (61b) in order to efficiently cool a surface fastener (1) formed along the outer surface of the die wheel (61). Additionally, a cooling liquid tank (not shown) is provided on the lower side of the die wheel (61) to immerse at least a portion of the die wheel (61) in the cooling liquid within the cooling liquid tank.

[0064] The nozzle section (62) is formed to continuously supply molten synthetic resin toward the die wheel (61). Specifically, the nozzle section (62) has a flow path for flowing the synthetic resin in a molten state, a nozzle tip face positioned opposite the die wheel (61), and a supply port opening in the nozzle tip face, and can continuously extrude (or flow) the molten synthetic resin toward the die wheel (61) from the supply port.

[0065] The pickup roller (70) has a pair of upper clamping rollers (71) and lower clamping rollers (72) that clamp and pull a face fastener (1) formed by a die wheel (61) from the top and bottom. On the outer surface of each upper clamping roller (71) and lower clamping roller (72), an unillustrated surface layer formed by an elastomer such as a polyurethane elastomer is provided.

[0066] On the downstream side of the pickup roller (70), a cutting device (not shown) having a cutter part that can be moved up and down is provided. In this cutting device, by lowering the cutter part toward the conveyed face fastener (1), the molded face fastener (1) can be cut to the required size.

[0067] Here, the cavity space (65) provided in the die wheel (61) to form the coupling element (20) of the present embodiment will be explained with reference to FIG. 4.

[0068] Each cavity space (65) of the die wheel (61) has a stem forming section (66) that forms the stem portion (21) of the coupling element (20) and a hook forming section (67) that forms the hook portion (30) of the coupling element (20) in a cross-sectional view (Fig. 4) that is orthogonal to the orthogonal direction (CD) of the wheel portion (61a). Additionally, the hook forming section (67) of the cavity space (65) has a first hook forming section (67a) that forms the first hook portion (31), a second hook forming section (67b) that forms the second hook portion (32), and a central protrusion (67c) that forms the bone portion (36).

[0069] The first hook forming section (67a) and the second hook forming section (67b) in the cavity space (65) are formed in a shape symmetric to each other. For this reason, the first hook forming section (67a) is mainly described here, and the description of the part of the second hook forming section (67b) that is similar to the first hook forming section (67a) is omitted.

[0070] The first hook forming portion (67a) of the cavity space (65) is formed corresponding to the first hook portion (31) of the coupling element (20), as shown in FIG. 4. In a cross-section orthogonal to the orthogonal direction (CD) of the cavity space (65), this first hook forming portion (67a) has a hook upper forming surface (67d) in the shape of a concave surface that is recessed upward, a hook lower forming surface (67e) in the shape of a convex surface that protrudes upward, and a hook tip forming surface (67f) formed extending from the hook upper forming surface (67d) to the hook lower forming surface (67e). The upper molding surface (67d) of the concave hook forms the upper surface (33) of the convex hook, and the lower molding surface (67e) of the convex hook forms the lower surface (34) of the concave hook.

[0071] The upper molding surface (67d) of the hook has an upper curved molding surface and a lower curved molding surface in an arc shape at a portion corresponding to the upper curved surface (33a) and the lower curved surface (34a) of the coupling element (20), respectively. In this case, the upper curved molding surface and the lower curved molding surface in an arc shape are each formed over a forming range of at least 50%, preferably at least 75%, and more preferably at least 90% of the upper curved surface (33a) and the lower curved surface (34a) in the cavity space (65).

[0072] The central protrusion (67c) of the wheel portion (61a) is positioned between the first hook forming portion (67a) and the second hook forming portion (67b) in the cross-section of the wheel portion (61a), and also protrudes toward the outer surface of the wheel portion (61a). The central protrusion (67c) has a protruding front end surface that curves in a convex shape, and this protruding front end surface is formed in the shape of an arc in the cross-section.

[0073] Here, regarding the wheel portion (61a) and cavity space (65) of the present embodiment, in the cross-section of the wheel portion (61a), the circumference including the arc formed by the upper curved molding surface of the first hook molding portion (67a) is defined as the cavity circumference (not shown), and the center of the arc formed by the upper curved molding surface is defined as the first molding center (not shown). The center of the arc formed by the lower curved molding surface of the first hook molding portion (67a) is defined as the second molding center (not shown). The center of the arc formed by the front end surface of the central protrusion (67c) is defined as the third molding center (not shown).

[0074] In addition, a fictitious straight line extending to connect the first forming center and the third forming center is defined as the upper forming inclination line (not shown), and a fictitious straight line extending to connect the second forming center and the third forming center is defined as the lower forming inclination line (not shown). A fictitious straight line extending parallel to the up and down direction while passing through the third forming center is defined as the forming perpendicular line (not shown).

[0075] In addition, the cavity circumference, the first molding center, the second molding center, the third molding center, the upper molding inclined line, the lower molding inclined line, and the molding waterline in the wheel portion (61a) correspond to the hook circumference (P), the first center (Cu), the second center (Cd), the third center (Cv), the upper inclined line (Lu), the lower inclined line (Ld), and the molding waterline (Lv) in the coupling element (20), respectively, so their specific illustration is omitted.

[0076] In this case, the cavity space (65) of the wheel part (61a) has an inclination angle (θ) of the upper molding inclined line relative to the molding perpendicular line that is 55° or more and 90° or less, so as to be identical to the shape of the coupling element (20), and also has a shape in which the cavity circumference touches the molding perpendicular line at one point or intersects it at two points. In particular, the cavity space (65) of the present embodiment has an inclination angle (θ) of the upper molding inclined line relative to the molding perpendicular line that is 59° or more and 65° or less, preferably 60°, and also has a shape in which the cavity circumference touches the molding perpendicular line at one point.

[0077] Accordingly, the coupling element (20) formed from the cavity space (65) can have a good balance of the effect of reducing the pulling force for pulling the coupling element (20) from the die wheel (61) as described above and the effect of increasing the coupling strength of the formed coupling element (20).

[0078] Additionally, the cavity space (65) of the wheel portion (61a) has a shape in which the upper molding inclination line and the lower molding inclination line are arranged on the same straight line, or the angle between the upper molding inclination line and the lower molding inclination line is 2° or less. Accordingly, when drawing the engaging element (20) from the cavity space (65) of the die wheel (61), it is difficult to cause plastic deformation of the hook portion (30). In this case, it is preferable that the upper molding inclination line and the lower molding inclination line are arranged on the same straight line.

[0079] Next, a method for manufacturing a cotton fastener (1) using the manufacturing device (50) described above will be explained.

[0080] First, molten synthetic resin is continuously supplied from the nozzle part (62) of the molding device (60) toward the outer surface of the die wheel (61). At this time, the die wheel (61) is rotated in one direction (counterclockwise in FIG. 3) at a predetermined rotational speed by the drive of the rotary drive roller (61b).

[0081] Accordingly, the base portion (10) of the surface fastener (1) is formed between the nozzle portion (62) and the die wheel (61) by the molten synthetic resin supplied from the nozzle portion (62). At the same time, the synthetic resin is filled into each cavity space (65) formed on the outer periphery of the die wheel (61), thereby forming a plurality of joining elements (20) having the same shape as each cavity space (65) integrally with the base portion (10).

[0082] Next, as described above, the surface fastener (1), in which the base portion (10) and a plurality of mating elements (20) are formed, is solidified (hardened) by cooling while rotating together with the die wheel (61). After that, the surface fastener (1) is continuously detached from the die wheel (61) by a pickup roller (70) that rotates while gripping the surface fastener (1) from above and below. At this time, each mating element (20) of the surface fastener (1) is drawn out from the cavity space (65) of the die wheel (61) while elastically deforming the hook portion (30), as shown in FIG. 4.

[0083] In this embodiment, in each cavity space (65) of the die wheel (61), the first hook forming section (67a) is formed as a forward drawing space extending in a direction opposite to the rotational direction of the die wheel (61), and the second hook forming section (67b) is formed as a reverse drawing space extending in the rotational direction of the die wheel (61). At the same time, each cavity space (65) provided in each coupling element (20) and the die wheel (61) is formed in a specific shape as described above.

[0084] Accordingly, when the surface fastener (1) is removed from the die wheel (61), even if the cavity space (65) has a second hook forming part (67b) of the reverse drawing space, the pulling force for pulling the engaging element (20) from the cavity space (65) (particularly the pulling force for pulling the second hook part (32) from the second hook forming part (67b)) can be reduced, thereby reducing the load applied to the hook part (30) of the engaging element (20). Because of this, it is difficult to cause plastic deformation in the hook part (30) of the engaging element (20) when pulling from the die wheel (61). Therefore, the surface fastener (1) pulled from the die wheel (61) may have a plurality of engaging elements (20) formed in the same shape as the cavity space (65) of the die wheel (61).

[0085] After that, the cotton fastener (1) detached from the die wheel (61) passes through the pickup roller (70) and is conveyed toward a cutting section not shown, where it is cut to a predetermined size and recovered. In addition, in the present invention, the cotton fastener (1) that has passed through the pickup roller (70) may be recovered by winding it into a roll shape on a recovery roller, for example, while still in a long state.

[0086] In addition, in the present invention, the manufacturing apparatus (50) or manufacturing method of the face fastener (1) is not limited to this embodiment and can be arbitrarily changed. For example, in this embodiment, the face fastener (1) is molded by continuously supplying molten synthetic resin from the nozzle part (62) toward the die wheel (61). However, in the present invention, the face fastener (1) may be molded using a pair of upper and lower molding rollers in which at least one of the die wheel (61) of the above-described embodiment is used. In this case, by continuously supplying molten synthetic resin from the nozzle part (62) toward the upper and lower pair of molding rollers, it is possible for each joining element (20) to mold a face fastener (1) having a specific shape as described above.

[0087] In the surface fastener (1) of the present embodiment manufactured by the above manufacturing method, it is difficult to cause plastic deformation in the hook portion (30) of the engaging element (20) when it is detached from the die wheel (61). Because of this, each engaging element (20) can stably have a shape corresponding to the cavity space (65) of the die wheel (61). Specifically, each engaging element (20) can stably have a shape formed symmetrically in the front and back directions with respect to a center position in the front and back directions, and the angle of inclination (θ) of the upper inclined line (Lu) with respect to the reference perpendicular line (Lv) is 55° or more and 90° or less, and the hook circumference (P) can stably have a shape that touches the reference perpendicular line (Lv) at one point or intersects it at two points.

[0088] By having each joining element (20) have a specific shape as described above, it is difficult to cause a difference in joining strength for the loop of the loop member between the first hook portion (31) and the second hook portion (32) of the joining element (20), thereby improving the joining strength for the loop of each joining element (20).

[0089] In addition, since the connecting element (20) has a shape with good balance and symmetry in the front and back, the appearance quality of the surface fastener (1) can be improved. Also, when the surface fastener (1) is touched from the side of the connecting element (20), it is easy to obtain a good texture and feel.

[0090] In addition, in this embodiment, each coupling element (20) has four unique shapes, such as a shape in which the hook portion (30) has a groove (36) that is recessed in an arc shape, a shape in which the hook upper surface (33) and hook lower surface (34) of the first hook portion (31) and the second hook portion (32) have an upper curved surface (33a) and a lower curved surface (34a) in an arc shape, a shape in which the angle of inclination (θ) of the upper inclined line (Lu) with respect to the reference perpendicular line (Lv) is 55° or more and 90° or less, and a shape in which the hook circumference (P) touches the reference perpendicular line (Lv) at one point or intersects at two points.

[0091] For this reason, in the design of the palm tree-shaped coupling element (20), for example, by setting a height dimension along the vertical direction from the upper surface of the base part (10) to the curved surface of the groove part (36) in the hook part (30) for the coupling element (20), it becomes possible to roughly and uniquely determine the overall shape of the coupling element (20) having all four of the aforementioned unique shapes.

[0092] In addition, when the palm tree-shaped coupling element (20) designed in this way is molded using a die wheel (61), it can stably provide a shape such as the design (shape such as the cavity space (65)) and can also exhibit high coupling strength with respect to the loop. Furthermore, by designing the coupling element (20) as described above, it is possible to expect a reduction in the burden applied during the design process and a reduction in the manufacturing cost of the surface fastener (1).

[0093] Examples

[0094] The present invention will be explained in more detail below with reference to examples. Furthermore, the present invention is not limited to the following examples.

[0095] Using the manufacturing apparatus (50) shown in FIG. 3, surface fasteners (1) of Examples 1 to 3, in which the shapes of the connecting elements (20) are different from each other, were manufactured. In addition, for comparison, surface fasteners of Comparative Examples 1 and 2 were manufactured.

[0096] Each face fastener (1) of Examples 1 to 3 is molded so that the joining element (20) has a different shape by making the height dimension along the vertical direction from the upper surface of the base portion (10) to the curved surface of the groove portion (36) in the joining element (20) different from each other. Meanwhile, the face fastener of Comparative Example 1 is molded so that the angle of inclination (θ) of the upper inclined line (Lu) with respect to the reference perpendicular line (Lv) of the joining element (20) is smaller than 55°. The face fastener of Comparative Example 2 is molded so that the hook circumference (P) of the joining element (20) is positioned at a location away from the reference perpendicular line (Lv).

[0097] In addition, for each face fastener (1) of molded Examples 1 to 3 and each face fastener of Comparative Examples 1 and 2, the joining element (20) was photographed from the left and right directions, and using the side view image of the joined element (20) taken therefrom, the minimum length dimension A of the joined element (20), the maximum thickness B of the hook portion (30), the height dimension from the base portion (10) to the curved surface of the groove portion (36) in the joined element (20), and the inclination angle (θ) of the upper inclination line (Lu) with respect to the reference perpendicular line (Lv) were measured. The measurement results are shown in Table 1 below.

[0098] In addition, for each coupling element (20) of Examples 1 to 3 and Comparative Examples 1 and 2, in order to clarify whether the hook circumference (P) touches the reference perpendicular (Lv) at one point, intersects at two points, or is positioned at a distance, the value of the aforementioned “A / 2B” was calculated from the measured values ​​of the minimum length dimension A and the maximum thickness B of the hook part (30). The result is also shown together in Table 1 below.

[0099] For example, when the value of “A / 2B” becomes 1.0, the coupling element (20) has a shape in which the hook circumference (P) touches the reference perpendicular (Lv) at one point. When the value of “A / 2B” becomes less than 1.0, the coupling element (20) has a shape in which the hook circumference (P) intersects the reference perpendicular (Lv) at two points. When the value of “A / 2B” is greater than 1.0, the coupling element (20) has a shape in which the hook circumference (P) is separated from the reference perpendicular (Lv).

[0100] In addition, regarding the molding process of forming each face fastener (1) of Examples 1 to 3 and each face fastener of Comparative Examples 1 and 2 using a die wheel (61), a simulation analysis was performed when drawing out the engaging element (20) from the cavity space (65) of the die wheel (61), thereby calculating the magnitude of the extraction force required to draw out the engaging element (20) from the cavity space (65) and the magnitude of the maximum load applied to the engaging element (20) during drawing. The results of the simulation analysis are also shown together in Table 1 below.

[0101] In addition, for each face fastener (1) manufactured in Examples 1 to 3 and each face fastener manufactured in Comparative Examples 1 and 2, a strength measurement was performed as follows to measure the magnitude of the joining strength for the loop of the joining element (20).

[0102] In measuring the strength of this joining strength, first, a wire with a diameter of 2 mm is attached to the first hook portion (31) or the second hook portion (32) of one joining element (20). Additionally, a tension measuring device is attached to the wire. Then, while pulling the wire upward, the tension generated in the wire is measured. Then, the magnitude of the tension measured just before the first hook portion (31) or the second hook portion (32) is deformed and the wire is removed from the joining element (20) is measured as the joining strength for the loop of the joining element (20).

[0103] Strength measurements as described above were performed on the first hook portion (31) of the five joining elements (20) provided in one face fastener (1) and the second hook portion (32) of the five joining elements (20). Afterwards, the average value of 10 measurements was calculated as the joining strength for the loops of the joining elements (20). The numerical value of the calculated joining strength is shown together in Table 1 below.

[0104]

[0105] As shown in Table 1, in the surface fasteners (1) of Examples 1 to 3, in which the connecting element (20) has a shape in which the angle of inclination (θ) of the upper inclined line (Lu) with respect to the reference perpendicular (Lv) is 55° or more and 90° or less, and the value of “A / 2B” is 1.0 or less, the magnitude of the extraction force calculated by simulation analysis is 2.0 N or less, and the maximum load of the connecting element (20) is also 0.70 N or less. In addition, as a result of visually observing the surface fasteners (1) of Examples 1 to 3 that were actually molded, each connecting element (20) has a shape that is symmetric in the front and back directions, and no connecting element (20) in which plastic deformation occurs in the hook portion (30) was confirmed.

[0106] In addition, regarding the surface fasteners (1) of Examples 1 to 3, the joining strength of the joining element (20) was measured and it was confirmed that the joining strength was greater than 6.0 N.

[0107] Meanwhile, in the surface fastener of Comparative Example 1, where the angle of inclination (θ) of the upper inclined line (Lu) with respect to the reference perpendicular line (Lv) of the engaging element (20) is smaller than 55°, the extraction force and the maximum load of the engaging element (20) calculated by simulation analysis showed high values ​​of 2.2N and 0.72N, respectively. When the surface fastener of Comparative Example 1, which was actually molded, was observed visually, a number of engaging elements (20) having an asymmetrical shape in the front and rear directions were confirmed. In the surface fastener of Comparative Example 1, it is thought that plastic deformation occurred in the hook portion (30) when the engaging element (20) was drawn out from the cavity space (65) of the die wheel (61).

[0108] In the surface fastener of Comparative Example 2, where the value of “A / 2B” is 1.05 (i.e., a surface fastener in which the hook circumference (P) of the coupling element (20) is positioned away from the reference perpendicular (Lv)), it was confirmed that the coupling strength of the coupling element (20) is lower than that of the surface fastener (1) of Examples 1 to 3.

[0109] Furthermore, the present invention is not limited to the embodiments and variations described above, and various modifications are possible as long as they have substantially the same configuration as the present invention and exhibit similar functional effects.

[0110] For example, in the first hook portion (31) and the second hook portion (32) of the coupling element (20) of the above-described embodiment, each hook upper surface (33) is formed as a curved surface that curves upward in a ridge shape with respect to the left-right direction, and each hook tip surface (35) is formed as a curved surface that curves downward in a ridge shape with respect to the left-right direction (see FIG. 2).

[0111] However, in the engaging element of the present invention, the hook upper surface and hook tip surface of each of the first hook portion and the second hook portion may be arranged parallel to the left-right direction. Even with a surface fastener having such an engaging element, it is difficult to cause a difference in the engaging strength for the loop of the loop member between the first hook portion and the second hook portion, just like the surface fastener (1) of the above-described embodiment, thereby improving the engaging strength for the loop of each engaging element. In addition, the engaging element may have a shape that is symmetrical and well-balanced in the front-back direction.

[0112] Furthermore, in the present invention, for example, the shape and thickness of the base portion of a surface fastener, and the size, arrangement, and formation density of the engaging elements are not limited and can be changed depending on the application of the surface fastener. Additionally, a molded portion with a three-dimensional shape other than the engaging elements, such as ribs or walls, may be integrally provided on the base portion of the surface fastener. Explanation of the symbols

[0113] 1 Cotton fastener 10 Base section 20 Connecting element 21 stem 30 Hook 31 First hook section 32 2nd hook section 33 Hook top surface 33a Upper curved surface (upper arc surface) 34 If you suddenly 34a Lower curved surface (lower arc surface) 35 Hook tip 36 bone 50 manufacturing device 60 molding device 61 Die wheel 61a Wheel section 61b rotary drive roller 62 nozzle part 65 Cavity space 66 Stem molding part 67 Hook forming section 67a First hook forming section 67b Second hook forming section 67c central protrusion 67d Upper hook forming surface 67e Lower hook forming surface 67f Hook tip forming surface 70 pickup roller 71 Upper clamping roller 72 Lower clamping roller A Minimum length dimension of the stem B Maximum thickness of the hook section Cu First center CD Second center Cv Third center Lu Upper slope line Ld Lower slope line Lv Standard repair P Hook circle θ Angle of inclination of the upper slope line with respect to the reference perpendicular

Claims

Claim 1 A surface fastener having a flat base portion (10) and a plurality of engaging elements (20) provided on the upper surface of the base portion (10), wherein each of the engaging elements (20) has a stem portion (21) extending from the base portion (10) and a hook portion (30) branching into two from the upper end of the stem portion (21) and extending while curved, wherein the hook portion (30) has a first hook portion (31) extending toward one side in the longitudinal direction of the base portion (10) and a second hook portion (32) extending toward the other side in the longitudinal direction, wherein when the engaging element (20) is viewed from the side view of the engaging element (20) in the width direction of the base portion (10) or in a cross-sectional view perpendicular to the width direction of the engaging element (20), the first hook portion (31) and the second hook portion (32) are such that Each has an upper curved surface (33a) formed as an arc-shaped convex surface while forming at least a part of the upper surface (33) of the hook portion (30), and a groove (36) formed as an arc shape is provided between the first hook portion (31) and the second hook portion (32), and in the side view or cross view of the coupling element (20), a virtual straight line connecting the center of the arc formed by the upper curved surface (33a) and the center of the arc formed by the groove (36) is defined as an upper inclined line (Lu), a circumference including the arc formed by the upper curved surface (33a) is defined as a hook circumference (P), a virtual straight line passing through the center of the arc formed by the groove (36) and parallel to the height direction of the coupling element (20) is defined as a reference perpendicular (Lv), and the upper side with respect to the reference perpendicular (Lv) A surface fastener characterized in that the angle of inclination (θ) of the inclined line (Lu) is 55° or greater and 90° or less, and the hook circumference (P) is tangent to the reference perpendicular (Lv) at one point or intersects at two points. Claim 2 In claim 1, in the side view or cross view of the coupling element (20), the first hook portion (31) and the second hook portion (32) each have a lower curved surface (34a) formed as an arc-shaped concave surface while forming at least a part of the lower surface of the hook portion (30), and a virtual straight line connecting the center of the arc formed by the lower curved surface (34a) and the center of the arc formed by the groove portion (36) is defined as a lower inclined line (Ld), and the upper inclined line (Lu) and the lower inclined line (Ld) are arranged on the same straight line, or the angle between the upper inclined line (Lu) and the lower inclined line (Ld) is 2° or less, a surface fastener. Claim 3 A surface fastener according to claim 1 or 2, wherein the inclination angle (θ) of the upper inclined line (Lu) is 60°. Claim 4 A surface fastener according to any one of claims 1 to 3, wherein, when the coupling element (20) is viewed from the longitudinal direction in the front or rear view of the coupling element (20), the upper surface (33) of the first hook portion (31) and the second hook portion (32) is formed as a curved surface that curves upward in a convex shape, or is formed as a flat plane parallel to the width direction. Claim 5 In any one of claims 1 to 4, in the side view or cross view of the coupling element (20), the upper curved surface (33a) having an arc shape is a surface fastener that is continuously provided over a range of 50% or more of the upper surface (33) of the hook portion (30). Claim 6 A molding device for forming a surface fastener (1) along a machine direction (MD), comprising a flat base portion (10) and a plurality of engaging elements (20) provided on the upper surface of the base portion (10), wherein each of the engaging elements (20) has a stem portion (21) extending from the base portion (10) and a hook portion (30) branching into two from the upper end of the stem portion (21) and extending while curved, wherein the hook portion (30) has a first hook portion (31) extending toward one side in the longitudinal direction of the base portion (10) and a second hook portion (32) extending toward the other side in the longitudinal direction, the device has a mold (61a) provided with a cavity space (65) for forming one of the engaging elements (20), wherein the cavity space (65) is formed at a cross-section orthogonal to the orthogonal direction (CD) of the molding device (60). In this, the apparatus has a first hook forming part (67a) for forming the first hook part (31), a second hook forming part (67b) for forming the second hook part (32), and a central protrusion (67c) having an arc-shaped tip surface while forming a groove (36) between the first hook part (31) and the second hook part (32); the first hook forming part (67a) and the second hook forming part (67b) each have an upper curved forming surface formed as an arc-shaped concave surface while forming at least a portion of the upper surface of the hook part (30) in the cross-section of the molding apparatus (60); and in the cross-section of the molding apparatus (60), an imaginary straight line connecting the center of the arc formed by the upper curved forming surface and the center of the arc formed by the tip surface of the central protrusion (67c) is formed upperly. Defined as an inclined line, and the circumference including the arc formed by the upper curved molding surface is defined as the cavity circumference, and a virtual straight line passing through the center of the arc formed by the front end surface of the central protrusion (67c) and parallel to the height direction of the coupling element (20) is defined as a reference perpendicular line (Lv), and the inclination angle of the upper molding inclined line with respect to the reference perpendicular line (Lv) isA forming device characterized by having an angle of 55° or greater and 90° or less, wherein the cavity circumference is tangent to the reference perpendicular (Lv) at one point or intersects at two points. Claim 7 In claim 6, in the cross-section of the molding device (60), the first hook molding part (67a) and the second hook molding part (67b) each have a lower curved molding surface formed as an arc-shaped convex surface while forming at least a part of the lower surface of the hook part (30), and a virtual straight line connecting the center of the arc formed by the lower curved molding surface and the center of the arc formed by the front end surface of the central protrusion (67c) is defined as the lower molding inclined line, and the upper molding inclined line and the lower molding inclined line are arranged on the same straight line, or the angle between the upper molding inclined line and the lower molding inclined line is 2° or less. Claim 8 A molding device according to claim 6 or 7, wherein the inclination angle of the upper molding inclined line is 60°.

Images