HK1124223B - Double-sided engaging element for slide fastener - Google Patents

Description

Double-sided engaging element for slide fastener

Technical Field

The present invention relates to a metallic double-sided engaging element for a slide fastener, having coupling surfaces on both front and rear surfaces thereof.

Background

In order to open/close an opening of a bag or the like, there is known a slide fastener which can be opened bidirectionally by providing two sliders so that head portions or rear ends of the two sliders collide. In a slide fastener capable of being opened bidirectionally, double-sided engaging elements whose front and rear coupling surfaces are formed in the same shape are used so as to equalize the feeling of bidirectional operation of opening backward and opening in the opposite direction. In particular, the metallic double-sided engaging element excellent in strength, appearance, durability and bending property is used for clothes and bags using a strong fabric.

For example, japanese utility model laid-open No.55-14252 has disclosed a device for improving strength against pulling force from the front and rear surfaces and bonding strength in the rotational direction with respect to the meshing axis in a slide fastener using a metal double-sided engaging element.

The double-sided engaging element for a slide fastener described in japanese utility model laid-open No.55-14252 has a central projecting portion in each of central portions of coupling bottom surfaces constituting both front and rear surfaces of a coupling head main body as viewed in a plan view thereof, and includes a pair of left and right leg portions provided astride an engaging element body portion having a thickness larger than a thickness between the coupling bottom surfaces continuous from the coupling head main body as viewed in a plan view. Left and right projecting portions projecting from the body portion toward the coupling head main body side rise from front and rear coupling bottom surfaces between the central rising portion and the engaging element body portion. Here, the outer side face of each of the left and right projecting portions is flush with the left and right side faces of the engaging element body portion. When the double-sided engaging elements are coupled to each other, the central elevated portion of the mating element fits into the tooth depression between the projecting portions, so that the front end surfaces of the projecting portions abut against the wide front end surface at the front end of the mating projecting portion. The double-sided engaging element having such a shape is used to improve strength against pulling force to the slide fastener and bonding strength in a rotational direction with respect to an engaging axis.

Further, in order to improve the sealing performance of a slide fastener using metal double-sided engaging elements, for example, a slide fastener using small double-sided engaging elements is disclosed in chinese utility model publication No. 2669667Y.

The double-sided engaging element for the slide fastener described in chinese utility model patent publication No.2669667Y includes: a sheet-bonding head body having bonding bottom surfaces on both front and rear surfaces thereof as viewed in a plan view; a thick body portion extending from the joint bottom surface in one direction over the step surface; and a pair of leg portions extending in a direction opposite to the coupling head main body from the body portion as viewed in a plan view. The central elevated portion is elevated from a central portion of the coupling bottom surface, and a pair of left and right projecting portions project from the body portion to left and right side surfaces of the central elevated portion. The pair of central elevated portions of the mating double-sided engaging element is detachably incorporated in a recess surrounded by the central elevated portion, the left and right projecting portions, and the step surface between the upper and lower projecting portions.

The double-sided engaging element for the slide fastener described in chinese utility model patent publication No.2669667Y is different from the double-sided engaging element described in japanese utility model patent publication No.55-14252 in that outer side surfaces of left and right projecting portions are formed inside upper and lower side surfaces of an engaging element body portion so that they can be easily bent forward or backward when the double-sided engaging elements are combined with each other.

Meanwhile, as for the front and rear surfaces mentioned in this specification, if one side surface of the coupling surface of the double-sided engaging element is regarded as the front surface, the surface on the opposite side is called the rear surface. As for the front and rear sides, a closed side when the double-sided engaging elements are opened or closed is regarded as a front side, and a released side on the opposite side is called a rear side in order to indicate a direction in which the slide fastener slides. Further, when the center elevated portion is seen in a plan view, both the left and right sides are both sides with respect to the front-rear direction, and the lateral pulling force refers to a direction of separating the double-sided engaging elements in the coupled state.

In the double-sided engaging element for the slide fastener described in japanese utility model laid-open No.55-14252, the dimension between the inner rise starting edges of the left and right projecting portions at the coupling portion is set to be substantially equal to the dimension between the left and right rise starting edges of the central rising portion. The left and right projecting portions and the central projecting portion are inclined in a mountain shape. With this configuration, when the double-sided engaging elements are coupled to each other, the movement between the double-sided engaging elements in the lateral pulling direction and the left-right direction is sometimes strengthened.

When the double-sided engaging elements are coupled to each other, the wide front end surfaces at the front end of each of the left and right projecting portions are closest in the coupled state. Therefore, compared with the large movement in the left-right direction between the double-sided engaging elements as described above, there is room for improvement as follows: the flexibility of the double-sided engaging elements in engagement is bent in a direction in which they overlap each other about the coupling axis when a pulling force is applied to the slide fastener, or the flexibility of the elements is distorted with respect to the coupling axis.

On the other hand, in the double-sided engaging element of the slide fastener described in chinese utility model publication N0.2669667Y at the same time, when the double-sided engaging elements are coupled to each other, the front ends of the left and right projecting portions parallel to each other become closest. Thus, the double-sided engaging elements in bending engagement around the coupling axis in the direction in which they overlap each other are poor in flexibility when a pulling force is applied to the slide fastener. Moreover, the flexibility of the twist with respect to the joining axis is also poor.

Disclosure of Invention

The present invention has been achieved to solve the problems of the conventional art, and an object of the present invention is to provide a double-sided engaging element for a slide fastener, in which a metallic double-sided engaging element is attached to a side edge of a fastener tape, the double-sided engaging element having improved flexibility, which allows the double-sided engaging element in engagement to be easily bent around a coupling axis and easily twisted with respect to the coupling axis. Another object of the present invention is to provide a double-sided engaging element for a slide fastener, which has a configuration of dispersing stress applied to a die for forming a central elevated portion elevated from a coupling head body of the double-sided engaging element and left and right projecting portions, so as to achieve a long service life of a mold.

In order to achieve the above object, the present invention provides a double-sided engaging element for a slide fastener, comprising: a sheet coupling head body having coupling bottom surfaces on both front and rear surfaces thereof; a thick body portion extending through the step surface in one direction from each of the joint bottom surfaces; a pair of left and right leg portions extending from the body portion; a central elevated portion elevated from the central portion on the front end side of each of the joint bottom surfaces; and a pair of right and left projecting portions which rise from each coupling bottom surface while projecting from the body portion toward each center elevated portion, wherein the center elevated portion of the mating element is detachably coupled in a tooth pit between the right and left projecting portions surrounded by the center elevated portion, the right and left projecting portions, and the step surface, characterized in that a dimension between inner elevation start edges of the right and left projecting portions is set smaller than a dimension between the right and left elevation start edges of the center elevated portion, and an outer corner of an end portion of each of the right and left projecting portions with respect to the center elevated portion has a first missing portion obtained by removing at least an elevation start edge side thereof.

In the double-sided engaging element for the slide fastener according to the invention, a dimension between inner elevation start edges of left and right projecting portions projecting from a body portion of the double-sided engaging element is set smaller than a dimension between left and right elevation start edges of a central elevated portion elevated from a central portion on a front end side of a coupling bottom surface. With this configuration, when the double-sided engaging elements are coupled to each other, a gap between the central elevated portion and each of the left and right projecting portions can be reduced so as to suppress movement in the direction of the left and right projecting portions of the double-sided engaging elements.

Preferably, the elevation startup edge of the first missing portion includes a straight line portion, and each extreme projecting end of the elevation startup edge is connected by a straight line at the front end portion of each of the right and left projecting portions, and an intersection angle between the straight line thereof and the straight line at the elevation startup edge of the first missing portion is 5 ° to 45 °.

On the side opposite to the central elevated portion, a first missing portion from which an outer corner is removed is formed at an end of each of the left and right projecting portions. With this configuration, when a force in a pulling direction is applied to the double-sided engaging elements in engagement, the double-sided engaging elements in engagement can be easily bent about the coupling axis in a direction in which they overlap each other, and the twisting flexibility with respect to the coupling axis can be improved. An intersection angle between a straight line connecting extreme projecting ends of the elevation startup edges at the front end portion of each of the right and left projecting portions and the elevation startup edge of the straight first missing portion is preferably set to 5 ° to 45 °. If the crossing angle is less than 5 °, it is difficult to bend the double-sided engaging elements around the coupling axis in the direction in which the double-sided engaging elements overlap, and if the crossing angle is greater than 45 °, the engagement between the double-sided engaging elements becomes easy to release.

Preferably, each elevation starting edge of the central elevated portion has at least one second missing portion for expanding a gap between each elevation starting edge and the extreme projecting ends of the left and right projecting portions on the left and right corners of the central elevated portion, adjacent to each extreme projecting end of the left and right projecting portions. Further, it is preferable that the elevation startup edge of the second missing portion includes a straight line portion, the second missing portion starts from the more inside of the inner elevation startup edge of each of the left and right projecting portions, and each extreme projecting end of the elevation startup edge is connected by a straight line at the front end portion of each of the left and right projecting portions, and an intersection angle between the straight line thereof and the straight line at the elevation startup edge of the second missing portion is set to 5 ° or more.

A second missing portion is formed on each of the right and left corners of the central elevated portion located adjacent to the extreme projecting ends of the right and left projecting portions. In addition, an inclined missing portion is formed in which an intersection angle between a straight line connecting extreme projecting ends of elevation startup edges at a front end portion of each of the right and left projecting portions and an elevation startup edge of a straight second missing portion is set to be less than 5 °. Therefore, the freedom around the coupling axis can be strengthened, and the flexibility of bending the double-sided engaging elements in the direction in which the double-sided engaging elements overlap each other and the flexibility of twisting with respect to the coupling axis can be improved.

According to the present invention, the above-described structure of the double-sided engaging element allows the stress applied to the die when the double-sided engaging element is formed by stamping to be dispersed, whereby the service life of the die having high hardness can be extended and the yield when the metal engaging element is formed can be improved. Therefore, a high-precision, inexpensive double-sided engaging element can be provided.

Drawings

Fig. 1 is a view of a coupling state of a slide fastener using double-sided engaging elements according to the present invention;

FIG. 2 is a perspective view of a double-sided engaging element attached to a side edge portion of a fastener tape;

FIG. 3 is an enlarged plan view of the coupling head main body and the body portion of the double-sided engaging element;

fig. 4 is an enlarged plan view of the coupling head main body and the body portion in the double-sided engaging element having the first missing portion formed in a curved line;

FIG. 5 is an enlarged view of the coupling state of the slide fastener shown in FIG. 1;

fig. 6 is a functional explanatory diagram for explaining the following states: bending the double-sided engaging elements when a tensile force is applied to the double-sided engaging elements in the engagement; and

fig. 7 is a view for explaining a manufacturing process when molding the double-sided engaging element by the square block.

Detailed Description

Exemplary embodiments of a double-sided engaging element and a slide fastener using the same according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a view of a coupling state of a slide fastener 10 using double-sided engaging elements 12 according to the present invention, and fig. 2 is a perspective view of the double-sided engaging elements 12 attached to a side edge portion of a fastener tape 16. The configuration of the double-sided engaging element 12 shown in fig. 2 indicates a state of an assembly having the closing leg portion 80 after the engaging element 12 is mounted on the fastener tape 16. The fastener tape 16 is not shown in the drawings for the purpose of convenience of description. Fig. 3 is a plan view in which representative portions of the coupling head main body 76 and the body portion 78 of the double-sided engaging element 12 are shown in a partially enlarged manner. Fig. 4 is a view showing an example of the double-sided engaging element 112, the double-sided engaging element 112 having a first missing portion 188 formed in a curved line instead of the first missing portion 88 including the linear portion shown in fig. 3. Fig. 5 is an enlarged view of the coupled state of the slide fastener 10 shown in fig. 1. Fig. 6 is a functional explanatory diagram for explaining flexibility when bending the double-sided engaging elements 12 with respect to a horizontal state in a direction in which the double-sided engaging elements 12 overlap each other around a coupling axis when a tensile force is applied to the double-sided engaging elements 12 in a coupled state. Fig. 7 is a view for explaining a manufacturing process when the double-sided engaging element 12 is molded by a flat square block.

As shown in fig. 1, the slide fastener 10 includes fastener stringers 18 each including a fastener tape 16 and metallic double-sided engaging elements 12 mounted in a row on a side edge portion of the fastener tape 16. The slide fastener 10 shown in fig. 1 can be used to open the slide fastener 10 bidirectionally by providing a slider for engaging and disengaging the double-sided engaging elements 12 so that the engaging elements 12 meet through a head or a rear end of the slider. Since the double-sided engaging elements 12 of the molded slide fastener 10 make the front and rear coupling surfaces symmetrical with respect to the front and rear sides, the feeling of opening/closing the slide fastener can be equalized regardless of whether it is opened in the forward direction or the reverse direction. Meanwhile, front and rear sides in this specification refer to FR directions indicated in fig. 1, and a lateral pulling direction refers to SP directions indicated in fig. 1.

Next, the shape of the double-sided engaging element 12 according to the present invention will be described with reference to fig. 2 and 3.

As shown in fig. 2 and 3, the double-sided engaging element 12 includes: a thin-sheet coupling head body 76 having coupling bottom surfaces 70 on both front and rear sides thereof; a thick body portion 78 extending from the body portion 78 in one direction over the step surface 82; and a pair of left and right leg portions 80 having the same thickness as the body portion 78 extending from the body portion 78. A central elevated portion 74 is formed at a central portion on the front end side of the coupling head main body 76, and the central elevated portion 74 is elevated in a mountain shape from the coupling bottom surface 70.

On the body portion 78 side of the coupling head main body 76, a pair of left and right projecting portions 72 raised from the coupling bottom surface 70 are formed so as to project from the body portion 78 toward the central raised portion 74. When the double-sided engaging elements 12 are coupled to each other, the central elevated portion 74 of the mating element is coupled in the pocket surrounded by the central elevated portion 74, the pair of left and right projecting portions 72, and the step surface 82.

In order to suppress the movement of the double-sided engaging elements 12 of the slide fastener 10 coupled to each other in the left-right direction (the movement in the front and rear directions with respect to the sheet in the embodiment shown in fig. 1), as shown in fig. 3, a dimension T0 between the inner raising start ends is set smaller than a dimension R0 between the left and right raising start ends of the central raised portion 74.

If the dimension T0 between the inner elevation starting ends of the left and right projecting portions 72 is set smaller than the dimension R1 between the left and right top edges of the central elevated portion 74, or the dimension T1 between the elevated portion top edges of the left and right projecting portions 72 is set smaller than the dimension R0 between the left and right elevation starting ends of the central elevated portion 74, the gap between the dents surrounded by the central elevated portion 74, the pair of left and right projecting portions 72, and the step surface 82 is reduced. Therefore, when a pulling force is applied to the slide fastener 10, the combined double-sided engaging elements cannot be easily bent in the overlapping direction about the coupling axis, and the flexibility of twisting with respect to the coupling axis is reduced. Further, a trouble sometimes occurs that it becomes difficult to smoothly effect the opening or closing of the slide fastener 10.

In order to secure flexibility and improve flexibility of twist with respect to the coupling axis when the double-sided engaging elements 12 are bent around the coupling axis in a direction in which the double-sided engaging elements 12 overlap each other by the double-sided engaging elements 12 coupled to each other, the first missing portion 88 is formed by eliminating an outer angle of each outer lifting start 85 of the left and right projecting portions 72.

Preferably, the first missing portion 88 is configured in a shape including a linear portion in an outer corner of the elevation startup edge, and an intersection angle α (see fig. 3) between a straight line connecting the extreme projecting ends 86 of the left and right projecting portions 72 and the elevation startup edge of the first missing portion 88 is set in a range of 5 ° to 45 °. For the same reason, it is preferable to form the second missing portions 96 on the left and right corners of the central elevated portion 74 adjacent to the extreme projecting ends 86 of the left and right projecting portions 72 so as to expand the gap with respect to the extreme projecting ends 86.

Preferably, the second missing portion 96 has a starting point inside the inner elevation starting edge 84 of the left and right projecting portions 72, and the elevation starting edge of the second missing portion 96 includes a linear portion. Further, it is preferable to form the inclined missing portion 98 at an angle β (see fig. 3) set to 5 ° or more with respect to the straight line connecting the extreme projecting ends 86 of the left and right projecting portions 72 so as to expand the gap with respect to the extreme projecting ends 86, and to form the curved portion 97 connecting the inclined missing portion 98 with the central elevated portion 74. Meanwhile, a manufacturing process of the double-sided engaging element 12 shown in fig. 2 and 3 will be described later with reference to fig. 7.

Although the first missing portion 88 shown in fig. 3 exhibits a shape including a linear elevation startup edge, the first missing portion 188 may be formed in a curved shape as shown in fig. 4. As shown in fig. 4, the central elevated portion 74 elevated from the coupling bottom surface 70 of the coupling head main body 76 includes: an inclined missing portion 98 having a starting point inside the inner elevation starting edge 84 of the left and right projecting portions 172; a second missing portion 96 formed by a curved portion 97 that connects the inclined missing portion 98 with both side edges of the central elevated portion 74 with curves. The pair of left and right projecting portions 172 projecting from the body portion 78 toward the central elevated portion 74 while being elevated from the joining bottom surface 70 each have a first missing portion 188 in which the projecting amount of the elevation startup edge decreases in a curved shape as it goes away in the left-right direction in plan view.

The first missing portion 188 can improve bending flexibility and twisting flexibility by delaying contact between the front end faces of the protruding portions 172 when the double-sided engaging elements 12 in engagement are bent in a direction in which they overlap around the coupling axis or twisted with respect to the coupling axis.

Next, the coupling state of the slide fastener 10 shown in fig. 1 will be described using an enlarged view of a partial sectional view of fig. 5.

As shown in fig. 5, the center elevated portion 74 and the pair of left and right projecting portions 72 elevated in a mountain shape from the sheet coupling bottom surface 70 are formed on both the front and rear surfaces of the double-sided engaging element 12. The central elevated portion 74 of the mating double-sided engaging element 12 intrudes into the pocket surrounded by the central elevated portion 74, the pair of right and left projecting portions 72, and the step surface 82, so that the double-sided engaging elements 12 are detachably coupled to each other.

When the mating central elevated portion 74 intrudes into the dent between the central elevated portion 74 and the step surface 82, the double-sided engaging element 12 is positioned in the lateral pulling direction (SP direction shown in fig. 5). Further, when the mating center elevated portion 74 intrudes between the pair of right and left projecting portions 72, so that the double-sided engaging element 12 is positioned in the right and left direction (front and rear surface direction with respect to the paper surface of fig. 5). Meanwhile, the front-rear direction in this specification refers to the FR direction shown in fig. 5, and the lateral pulling direction refers to the SP direction shown in fig. 5.

Next, flexibility in the coupling when a pulling force is applied to the double-sided coupling elements 12 of the slide fastener 10 in the coupling will be described with reference to fig. 6.

When a pulling force FT in occlusion is applied to the double-sided engaging elements 12R, 12L as shown in fig. 6, the double-sided engaging element 12R (indicated by a solid line) and the double-sided engaging element 12L (indicated by a broken line) are bent in a direction in which they overlap around the coupling axis.

Since the central elevated portion 74L of the mating double-sided engaging element 12L is disposed between the central elevated portion 74R of the double-sided engaging element 12R and the step surface 82R, the double-sided engaging element 12R and the double-sided engaging element 12L are positioned in the lateral pulling direction (SP direction shown in fig. 6) of the slide fastener 10. Further, since the center elevated portion 74L of the mating double-sided engaging element 12L is disposed between the pair of left and right projecting portions 72R formed on the double-sided engaging element 12R, the double-sided engaging element 12R and the double-sided engaging element 12L are positioned in the left-right direction (LR direction shown in fig. 6).

In the double-sided engaging elements 12R, 12L of the invention, the dimension T0 between the inner rise starting ends of the protruding portions 72R, 72L is set smaller than the dimension R0 between the left and right rise starting ends of the central rising portions 74R, 74L. With this configuration, even when the double-sided engaging element 12R and the double-sided engaging element 12L are bent in the direction in which they overlap each other around the coupling axis, the movement in the left-right direction (LR direction shown in fig. 6) between the double-sided engaging element 12R and the double-sided engaging element 12L in engagement is suppressed, thereby improving the engagement strength.

The left and right projecting portions 72R, 72L of the double-sided engaging elements 12R, 12L of the present invention have first missing portions 88 formed by removing the outside corners. Thus, when a pulling force is applied to the slide fastener 10 in which the double-sided engaging element 12R is combined with the double-sided engaging element 12L, the double-sided engaging element 12R and the double-sided engaging element 12L can be greatly bent in the direction in which they overlap around the combining axis by delaying the contact between the first missing portions 88R and 88L.

Preferably, the first missing portion 88R is configured to include a straight line portion, and the intersection angle α between a straight line connecting the extreme projecting ends 86R of the left and right projecting portions 72R and the elevation startup edge of the first missing portion 88R is set to 5 ° to 45 °. Therefore, it is possible to ensure flexibility in bending around the coupling axis and flexibility in twisting with respect to the coupling axis while preventing the double-sided engaging elements 12R, 12L from slipping off. Meanwhile, the same effect can be obtained with the double-sided engaging element 112 having the curved first missing portion 188 shown in fig. 4.

For the same reason, it is preferable that a straight inclined missing portion 98R is formed at the elevation start edge on each of the right and left corners of the central elevated portion 74R, the inclined missing portion 98R forming an angle β of 5 ° or more with respect to a straight line connecting the extreme projecting ends 86R of the right/left projecting portions 72 so as to expand the gap with respect to the extreme projecting ends 86R. Also, a curved portion 97R that is curved so as to connect the inclined missing portion 98R with the central elevated portion 74R is formed.

A manufacturing process of molding the double-sided engaging element 12 from a flat square block will be described below using fig. 7.

First, a square block 100 having the same thickness as the body portion 78 and the leg portion 80 of the double-sided engaging element 12 is intermittently fed from top to bottom in fig. 7. First, in the first process (1ST), the bonding bottom surface 70, the central elevated portion 74, the pair of left and right projecting portions 72, and the step surface 82 of the bonding head main body 76 are molded using a double-sided die in which the portions are symmetrically formed. Thereafter, an interval of several pitches (2ST) is fed and in a third process (3ST), unnecessary portions 102 are cut out from the bottom and side portions of the leg portion 80.

In the following fourth process (4ST), the coupling head main body 76 and the body portion 78 of the double-sided engaging element 12 are cut off integrally so as to obtain the double-sided engaging element 12 at the endmost portion. Meanwhile, when the double-sided engaging element 12 is cut from the square block 100 in the fourth process, one side edge of the fastener tape 16 is disposed between the pair of leg portions 80. Then, the leg portion 80 is deformed inward to attach the double-sided engaging element 12 to the side edge portion of the fastener tape 16. In the example shown in fig. 7, the outer shape of the coupling head main body 76 and the inner shape of the leg portion 80 are the same in order to improve the yield of the flat square 100 in the example shown in fig. 7.

In the first process and the second process, stress may be concentrated on a thin portion of the press die, particularly a portion for molding a bottom surface in which the central elevated portion 74 and the protruding portion 72 are closest to each other when the front and rear surfaces of the coupling head main body 76 are formed. Thus, it is considered that a part of the die may be damaged due to fatigue after the punching operation is performed hundreds or thousands of times. Then, by forming a portion where stress is easily concentrated in the mold in a thick configuration so as to disperse the stress, the service life can be extended so as to stabilize the accuracy of the metallic double-sided engaging element 12 for a long time, and the manufacturing cost of the metallic double-sided engaging element 12 can be reduced.

For example, in the coupling head main body 76 shown in fig. 3, the first missing portion 88 is effectively formed by eliminating the outer corner portion of the right/left protruding portion 72 so as to increase the gap between the curved portion 97 of the central elevated portion 74 and the first missing portion 88 as much as possible, so that the elevation start edge for forming the first missing portion 88 is released without being directed to the central elevated portion 74. Further, by forming the straight inclined missing portion 98 on the elevation startup edge of the central elevated portion 74 so as to form the curved portion 97 connecting the inclined missing portion 98 with both side edges of the elevation startup edge of the central elevated portion 74, it is possible to increase the gap between the curved portion 97 of the central elevated portion 74 and the first missing portion 88. By specifying the configuration of the double-sided engaging element 12, it is possible to prevent the generation of cracks, which may be generated in a section from the bent portion 97 to the first missing portion 88 due to the mold, without changing the size of the joint between the central elevated portion 74, the pair of left and right projecting portions 72, and the step surface 82, the tooth depression surrounded by the central elevated portion 74, the pair of right and left projecting portions 72, and the step surface 82, and the central elevated portion 74, or without reducing the engaging strength between the engaging elements.

Also, second missing portions 96 for expanding the gap with respect to the extreme projecting ends 86 of the left and right projecting portions 72 are formed on the left and right corners of the central elevated portion 74, whereby the gap between the central elevated portion 74 and the projecting portions 72 can be increased so as to prevent cracks that may be generated on the boundary between the central elevated portion 74 and the projecting portions 72 of the mold.

The slide fastener having the double-sided engaging elements of the present invention can be applied to, for example, clothes and bags formed of thick fabric, such as denim, leather, and synthetic leather. Since the slide fastener of the present invention has flexibility to bend around the coupling axis and flexibility to twist with respect to the coupling axis, it can operate to open in the forward direction or the reverse direction even when the slide fastener is bent.

Claims (4)

1. A double-sided engaging element (12, 112) for a slide fastener (10), comprising:

a sheet-coupling head body (76) having coupling bottom surfaces (70) on both front and rear surfaces thereof;

a thick body portion (78) extending from each of the coupling bottom surfaces (70) through the step surface (82) in one direction;

a pair of left and right leg portions (80) extending from the body portion (78);

a central elevated portion (74) elevated from the central portion on the front end side of each of the joint bottom surfaces (70); and

a pair of left and right projecting portions (72, 172) rising from each coupling bottom surface (70) while projecting from the body portion (78) toward each central elevated portion (74), wherein the central elevated portion (74) of the mating element is detachably coupled in a tooth depression between the left and right projecting portions (72, 172) surrounded by the central elevated portion (74), the left and right projecting portions (72, 172) and the step surface (82), characterized in that,

the dimension (T0) between the inner elevation start edges (84) of the left and right projecting portions (72, 172) is set smaller than the dimension (R0) between the left and right elevation start edges of the central elevated portion (74), and

an outer corner of an end portion of each of the right and left projecting portions (72, 172) with respect to the central elevated portion (74) has a first missing portion (88, 188) obtained by removing at least an elevation start edge side thereof.

2. The double-sided engaging element (12) for the slide fastener (10) according to claim 1, wherein the rise-starting edge of the first missing portion (88) includes a straight line portion, and

each extreme projecting end (86) of the elevation startup edge is connected by a straight line at a front end portion of each of the left and right projecting portions (72), and an intersection angle (α) between the straight line thereof and the straight line at the elevation startup edge of the first missing portion (88) is 5 ° to 45 °.

3. The double-sided engaging element (12, 112) for the slide fastener (10) according to claim 1 or 2, wherein each elevation start edge of the central elevated portion (74) has at least one second missing portion (96) adjacent to each extreme projecting end (86, 186) of the left and right projecting portions (72, 172) for expanding a gap between each elevation start edge and the extreme projecting ends (86, 186) of the left and right projecting portions (72, 172) at left and right corners of the central elevated portion (74).

4. The double-sided engaging element (12, 112) for the slide fastener (10) according to claim 3, wherein the elevation start edge of the second missing portion (96) includes a straight line portion, the second missing portion (96) starts from a further inside of the inner elevation start edge of each of the left and right projecting portions (72, 172), and

the second missing portion (96) includes an inclined missing portion (98) connecting each extreme projecting end (86, 186) of the elevation start edge by a straight line at the front end portion (72, 172) of each of the right and left projecting portions, and an intersection angle (β) between the straight line thereof and the straight line at the elevation start edge of the second missing portion (96) is set to 5 ° or more, the inclined missing portion (98) serving to expand the gap with respect to the projecting portion (72, 172).