FASTENER STRINGER, SLIDE FASTENER, AND METHOD FOR PRODUCING STOPPER COMPONENT AND SLIDE FASTENER

TECHNICAL FIELD

The present disclosure relates to fastener stringer, slide fastener and methods for producing stop part and slide fastener.

BACKGROUND ART

There is a need to enhance user-friendliness in connection to opening and closing operation of slide fastener.

Patent literature 1 relates to a stop member of slide fastener and discloses that simplified operation of stop members is facilitated using magnets. In particular, when first and second bases of first and second parts are stacked, magnetic attraction or magnetic repulsion is effected between them and the second base rotates relative to the first base. At this instant, a second insert of the second member pivots toward an interspace between upper and lower flanges of slider. In such a way, the operational burden of stop member required for closing the slide fastener would be reduced. The permanent magnets are housed in housing portions of the bases.

Patent literature 2 discloses that a magnet is attached, by fitting, to a recess of a sliding plate.

Patent literature 3 discloses a slide fastener having magnetically attractable elements. Elastomer including non-magnetized particles is injection-molded, followed by application of magnetic field to magnetize those particles. Strength and position of the magnetic field would be appropriately controlled so that the magnetized particles would form a linear cluster in the elastomer. Then, the elastomer is solidified and a processing is performed for shaping it into fastener elements.

Patent literature 4 discloses that a non-magnetized magnet is attached to a tie and then magnetized.

CITATION LIST
Patent literature

[PTL 1] International Publication No. 2019/175944

[PTL 2] Japanese Patent No. 4 152 216

[PTL 3] U.S. Pat. No. 10 709 212

[PTL 4] Japanese registered utility-model 3 078 682

SUMMARY
Technical Problem

An aspect of the present disclosure aims to strengthen a structure that holds a magnetic body in a stop part.

Solution to Problem

Fastener stringer according to an aspect of the present disclosure includes: a fastener tape provided with a fastener element; and a stop part adhering to the fastener tape at a position adjacent to the fastener element, wherein the stop part includes a magnetic body and a base portion in which an entirety of the magnetic body is embedded, the base portion includes first and second resin portions which are distinguishable based on an interface formed between the first and second resin portions, and the first and second resin portions are arranged to cover separate first and second regions, respectively, in at least one surface of the magnetic body. The first and second resin portions may directly cover the first and second regions respectively. The respective resin portions and the respective regions may be in direct contact, and there may be no interspace between the portion and the region.

In some embodiments, the at least one surface of the magnetic body is covered by the first and second resin portions in a complemental manner; or in each surface of the magnetic body, the first and second regions are covered by the first and second resin portions respectively. In some embodiments, the first resin portion has one or more exposed surfaces exposed as not covered by the second resin portion. The exposed surface may extend radially with respect to a central axis of the magnetic body. In some embodiments, the second resin portion has an exposed surface that extends radially with respect to a central axis of the magnetic body. In some embodiments, a stack portion of the first and second resin portions is provided on a central axis of the magnetic body.

In some embodiments, the base portion has an axial protrusion in which the magnetic body is embedded, and a top surface of the axial protrusion includes exposed surfaces of the first and second resin portions. The base portion may have an axial protrusion in which the magnetic body is embedded, and a side wall of the axial protrusion may be configured by alternate arrangement of a wall of the first resin portion and a wall of the second resin portion in a circumferential direction. The base portion may have a recess having a bottom surface with the magnetic body arranged directly beneath the bottom surface, and the bottom surface of the recess may include exposed surfaces of the first and second resin portions.

In some embodiments, (a) the base portion is provided with an axial protrusion in which the magnetic body is embedded at least partially, and a side wall of the axial protrusion includes a wall of first resin portion and a wall of second resin portion; or (b) the base portion is provided with a recess having a bottom surface with the magnetic body arranged directly beneath the bottom surface, and the bottom surface of the recess includes an exposed surface of the first resin portion and an exposed surface of the second resin portion.

The first resin portion may be configured to receive the magnetic body, and the second resin portion may configure a remainder of the stop part other than the first resin portion. The magnetic body may be a permanent magnet having a pair of main surfaces arranged to cross a magnetic axis and a side surface connecting outer rims of the pair of main surfaces.

Slide fastener according to another aspect of the present disclosure is a slide fastener including a pair of fastener stringers; and a slider movable to open and close the pair of fastener stringers, wherein each of the pair of fastener stringers is any one of fastener stringers described above in which a permanent magnet is provided as the magnetic body, a pair of stop parts in the pair of fastener stringers include the permanent magnets so as to be magnetically attracted each other to cause a stack of the pair of stop parts, one of the pair of stop parts has a sloped surface that is sloped as extending along a circumferential direction with respect to a magnetic axis of the permanent magnet, and the other one of the pair of stop parts has a sliding portion that slides on the sloped surface in accordance with a magnetic attraction between the permanent magnets of the pair of stop parts.

A method of producing a stop part according to yet another aspect of the present disclosure is a method of producing a stop part adhered or to be adhered to a fastener tape of a fastener stringer, the method including: performing an injection molding such that a magnetic body is embedded in the stop part; and applying a magnetic field to the stop part to magnetize the magnetic body after said injection molding.

In some embodiments, said injection molding includes at least two injection moldings, a first region of at least one surface of the magnetic body is covered by a first resin portion during an initial injection molding, and a second region of at least one surface of the magnetic body is covered by a second resin portion during a following injection molding.

A method of producing a slide fastener according to yet further another aspect of the present disclosure is a method of producing a slide fastener having magnetically attractable but separable stop members, the method including: combining, as a pair, fastener stringers of any one of the above-described ones; and applying a magnetic field having a constant direction to stop parts which are included and coupled in the pair to magnetize magnetic bodies respectively embedded in the stop parts.

Advantageous Effects of Invention

According to an aspect of the present disclosure, facilitated is that a structure holding a magnetic body in a stop part is strengthened.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic top view of a slide fastener in an open state according to an aspect of the present disclosure.

FIG. 2 is a schematic bottom view of the left fastener stringer.

FIG. 3 is a schematic right side view of the left fastener stringer.

FIG. 4 is a schematic bottom view of the right fastener stringer.

FIG. 5 is a schematic cross-sectional schematic view of the left fastener stringer, illustrating a schematic cross-sectional configuration of a left stop part taken along a chain line X5-X5 in FIG. 1.

FIG. 6 is a schematic cross-sectional view of the right fastener stringer, illustrating a schematic cross-sectional configuration of a right stop part taken along a chain line X6-X6 in FIG. 4.

FIG. 7 is a schematic view illustrating that an insert of the right stop part is automatically inserted into the inside of a slider in accordance with magnetic attraction between permanent magnets in the left and right stop parts.

FIG. 8 is a schematic flowchart illustrating a method of producing a stop member.

FIG. 9 is a schematic process diagram illustrating that a first region in each surface of the left magnetic body will be covered by a first resin portion through a process of first injection molding.

FIG. 10 is a schematic process diagram illustrating that a first region in each surface of the right magnetic body will be covered by a first resin portion through a process of first injection molding.

FIG. 11 is a schematic process diagram illustrating that, through a process of second injection molding, a second region (not shown in FIG. 11) in each surface of the left magnetic body will be covered by a second resin portion, and the first resin portion will also be covered by the second resin portion.

FIG. 12 is a schematic process diagram illustrating that, through a process of second injection molding, a second region in each surface of the right magnetic body will be covered by a second resin portion, and the first resin portion will also be covered by the second resin portion.

FIG. 13 is a schematic perspective view of a first molded part in which the left magnetic body is partially covered by the first resin portion.

FIG. 14 is a schematic top view of the first molded part shown in FIG. 13.

FIG. 15 is a schematic bottom view of the first molded part shown in FIG. 13.

FIG. 16 is a schematic cross-sectional view of the first molded part shown in FIG. 15, illustrating a cross-section taken along a chain line X16-X16 in FIG. 15.

FIG. 17 is a schematic cross-sectional view of the first molded part shown in FIG. 15, illustrating a cross-section taken along a chain line X17-X17 in FIG. 15.

FIG. 18 is a schematic perspective view of the first molded part in which the right magnetic body is partially covered by the first resin portion.

FIG. 19 is a schematic top view of the first molded part shown in FIG. 18.

FIG. 20 is a schematic bottom view of the first molded part shown in FIG. 18.

FIG. 21 is a schematic cross-sectional view of the first molded part shown in FIG. 20, illustrating a cross-section taken along a chain line X21-X21 in FIG. 20.

DESCRIPTION OF EMBODIMENTS

Hereinafter, various embodiments and features will be described with reference to drawings. A skilled person would be able to combine respective embodiments and/or respective features without requiring excess description, and would appreciate synergistic effects of such combinations. Overlapping description among the embodiments are basically omitted. Referenced drawings aim mainly for describing inventions and are simplified for the sake of convenience of illustration. The respective features should be appreciated as universal features not only effective to a fastener stringer and stop part presently disclosed but also effective to other various fastener stringers and stop parts not disclosed in the present specification.

In the following descriptions, Front-rear direction matches a direction (up-down direction when FIG. 1 is viewed in front) in which a slider moves so as to open and close a slide fastener. Left-right direction is a direction (left-right direction when FIG. 1 is viewed in front) orthogonal to the front-rear direction and parallel to a tape surface of a fastener tape. Up-down direction is a direction orthogonal to the front-rear direction and perpendicular to a tape surface of the fastener tape. The tape surface of the fastener tape is a surface for defining a thickness of the fastener tape.

The slide fastener 1 has left and right fastener stringers 2a and 2b, and a slider 40 for opening and closing the slide fastener 1. As the slider 40 moves frontward, the slide fastener 1 is closed and the left and right fastener stringers 2a and 2b are coupled. As the slider 40 moves rearward, the slide fastener 1 is opened and the left and right fastener stringers 2a and 2b are decoupled.

The slider 40 has an upper wing 81, a lower wing, and an interconnection pillar 83 that interconnects the upper wing 81 and the lower wing. Front mouths are arranged at the left and right sides of the interconnection pillar 83. A rear mouth is arranged at the opposite side of these front mouths. An insert 7a described below is inserted into the inside of the slider 40 via the rear mouth of the slider 40. Flanges 86, downwardly protruded and extending along the front-rear direction, are arranged at the left and right side-edges of the upper wing 81. Flanges, upwardly protruded and extending along the front-rear direction, are arranged at the left and right side-edges of the lower wing. An insert 7b described below is inserted into the interspace between these upper and lower flanges. When the slider 40 is situated frontward away from the stop parts 5a and 5b, the fastener tape 3b has been inserted in the interspace between the upper and lower flanges of the slider 40. Each of the fastener stringers 2a and 2b has a fastener tape 3a,3b provided with a fastener element 4a,4b, and a stop part 5a,5b adhering to the fastener tape 3a,3b at a position adjacent to the fastener element 4a,4b. The fastener tape is a belt-like member having softness and elongated in the front-rear direction, and is a woven fabric, knitted fabric or mixture of these fabrics. The fastener element is configured to be engageable with a partner element and for example, is a resin-made or metal-made element or a coil-like element of helically wound monofilament. The fastener element is adhered to the fastener tape through injection molding, swaging, sewing or adhesion. The illustrated fastener element is a resin-made element having a base portion, a neck and a head. The base portion adheres to the side-edge portion of the fastener tape.

The stop parts 5a and 5b are capable of being coupled in a separable manner. Each of the stop parts 5a and 5b has a base portion 6a,6b and an insert 7a,7b that extends toward the fastener element 4a,4b away from the base portion 6a,6b (i.e. frontward). The entireties of magnetic bodies 30a and 30b are embedded in the base portions 6a and 6b (See FIGS. 5 and 6) respectively. The magnetic bodies 30a and 30b have different shapes and here, the magnetic body 30a has a cylindrical shape and the magnetic body 30b has a discoid shape. As described above, the insert 7a is inserted into the inside of the slider 40 via its rear mouth. The insert 7b is inserted into the inside of the slider 40 via the interspace between the flange of the upper wing 81 and the flange of the lower wing. Note that, the configurations of the stop parts 5a and 5b can be inverted in the left-right direction.

The base portion 6a of the left stop part 5a has an axial protrusion 11 in which the magnetic body 30a is embedded. The axial protrusion 11 is arranged to protrude downward. The base portion 6b of the right stop part 5b has a recess 21 having a bottom surface 21b with the magnetic body 30b arranged directly beneath the bottom surface 21b. The magnetic bodies embedded in the base portions of the stop parts illustrated in FIGS. 1 to 5 and 6 are permanent magnets produced through magnetization of non-magnetized magnetic bodies (the magnetic bodies 30a and 30b may be referred to as permanent magnets 30a and 30b hereinbelow). Accordingly, when the base portion 6a of the left stop part 5a and the base portion 6b of the right stop part are positioned to be spatially close to each another (e.g. when the base portion 6b is arranged beneath the base portion 6a), a magnetic attraction is effected between the permanent magnet 30b of the base portion 6b and the permanent magnet 30a of the base portion 6a, allowing the base portion 6a and the base portion 6b to be stacked one another and allowing the axial protrusion 11 of the base portion 6a to fit to the recess 21 of the base portion 6b.

The permanent magnet 30a,30b may be a rare-earth magnet such as a neodymium magnet. The permanent magnet 30a,30b has, as total 3 surfaces, a pair of main surfaces 34 and 35 arranged to cross a magnetic axis AX1,AX2 (or that define a thickness of the permanent magnet), and a side surface 36 connecting the outer rims of the main surfaces 34 and 35 of the pair (See FIGS. 5 and 6). The side surface 36 extends along the magnetic axis AX1,AX2 at a position radially outward from the magnetic axis AX1,AX2 to couple the outer rim of the main surface 34 and the outer rim of the main surface 35.

The magnetic axis AX1,AX2 of the permanent magnet 30a,30b matches a central axis of the magnetic body 30a,30b. The magnetic axis is an axis extending along an arrangement direction of N-pole and S-pole of the permanent magnet, and is defined based on the lines of magnetic force formed about the permanent magnet. The central axis AX1 of the magnetic body 30a matches a central axis of the axial protrusion 11. The central axis AX2 of the magnetic body 30b matches a depth direction of the recess 21. Note that the permanent magnets 30a and 30b can be shaped like a prism or a polygonal plate. Other shapes such as a cone, a pyramid, or a sphere can also be employed.

The base portion 6a has an outer peripheral portion 12 arranged around the axial protrusion 11. Sliding portions 13p,13q,13r are arranged in the outer peripheral portion 12. The base portion 6b has an outer peripheral portion 22 arranged around the recess 21. Sloped surfaces 23p,23q,23r are arranged in the outer peripheral portion 22. While the axial protrusion 11 fits to the recess 21 in accordance with the magnetic attraction between the permanent magnets as described above, the sliding portion 13p,13q,13r and the sloped surface 23p,23q,23r are brought into contact and the sliding portion 13p,13q,13r slides down the sloped surface 23p,23q,23r, resulting in a rotation of the base portion 6b relative to the base portion 6a. It can be said that the magnetic attraction effected in the axial direction is converted into a rotational force around the axial direction.

The insert 7a is configured to be open at the right side to receive the insert 7b. As shown in FIG. 3, the insert 7a has an upper plate 14 and a lower plate 15, and an insertion space 16 is defined between the plates 14 and 15. Also, as shown in FIG. 2, a bar 8a is arranged adjacent to the insert 7a on the both upper and lower sides of the fastener tape 3a, and a flange passage is defined on the both upper and lower sides of the fastener tape 3a. Similar to the insert 7a, the bar 8a extends frontward from the base portion 6a. The flange of the slider 40 is inserted into the flange passage between the insert 7a and the bar 8a, facilitating that the slider 40 is kept on the insert 7a.

The insert 7b has an insertion end shaped to taper as extending leftward away from the fastener tape 3b, and the insertion end will be smoothly inserted into the interspace between the right-side upper and lower flanges of the slider 40. Modified fastener element 4b′ is coupled to a front end of the insert 7b, allowing the slider 40 to smoothly move onto the fastener elements 4a and 4b from a position over the stop member. The bar 8b is connected to the insert 7b at the opposite side of the insertion end. The bar 8b is arranged to protrude on the both upper and lower surfaces of the fastener tape 3b and collides with the right-side upper and lower flanges of the slider 40. The bar 8b defines a stop position for the insert 7b that is to be inserted into the inside of the slider 40.

As shown in FIG. 7, when the slider 40 is positioned at a rearmost position (i.e. when the insert 7a is inserted into the inside of the slider 40) and when the base portion 6b is positioned beneath the base portion 6a, the magnetic attraction would be effected between the permanent magnet 30a of the base portion 6b and the permanent magnet 30b of the base portion 6a. This magnetic attraction allows the base portion 6a and the base portion 6b to be stacked one another and allows the axial protrusion 11 of the base portion 6a to fit to the recess 21 of the base portion 6b. While the axial protrusion 11 fits to the recess 21 (i.e. while the base portions 6a and 6b approach one another along the axial direction), the sliding portion 13p,13q,13r and the sloped surface 23p,23q,23r are brought into contact and the sliding portion 13p,13q,13r slides down the sloped surface 23p,23q,23r. In accordance with this, the base portion 6b rotates counterclockwise relative to the base portion 6a, and the insert 7b is inserted into the inside of the slider 40 via the interspace between the right-side upper and lower flanges of the slider 40. As the slider 40 moves frontward, the insert 7b is inserted into an insertion space 16 of the insert 7a and the left and right stop parts 5a and 5b are coupled. As the slider 40 moves frontward further, the left and right fastener elements 4a and 4b are engaged.

The sliding portions 13p,13q,13r are arranged in a circumferential direction about the magnetic axis AX1 of the permanent magnet 30a. Likewise, the sloped surfaces 23p,23q,23r are arranged in a circumferential direction about the magnetic axis AX2 of the permanent magnet 30b. Each sloped surface is sloped as extending in a circumferential direction about the magnetic axis AX2 of the permanent magnet 30b. The sliding portion 13p,13q,13r slides on (descends) the sloped surface 23p,23q,23r in accordance with the magnetic attraction between the permanent magnets 30a and 30b. The arrangement of 3 sliding portions allows increased rotational stability, but the arrangement of just one sliding portion might be sufficient. The same applies to the sloped surface. Of course, it is also possible to omit the sliding portions and the sloped surfaces and to rotate the base portion 6b relative to the base portion 6a by hand. The permanent magnets 30a and 30b would be aligned such that the respective magnetic axes AX1 and AX2 match, and thus it would be possible to omit the axial protrusion 11 and the recess 21.

The base portion 6a has a guide 17 arranged adjacent to and rearward of the insert 7a and protruded downward likewise the axial protrusion 11. The guide 17 is arranged to define a groove that is in spatial communication to the orifice of the insert 7a, and has a guide surface that is inclined downward rightwardly. When the base portions 6a and 6b are attracted magnetically each other, the insert 7b may possibly be placed onto the guide surface of the guide 17. Even in this case, the insert 7b can descend on the guide surface of the guide 17 and pivot clockwise to the right. The insert 7b can enter into the inside of the slider 40 via the interspace between the right-side upper and lower flanges of the slider 40 similar to the above, after descending across the guide surface of the guide 17.

In the present embodiment, the base portion 6a includes first and second resin portions 41a and 42a which are distinguishable based on an interface formed between the portions (see FIGS. 2, 3 and 5). The first and second resin portions 41a and 42a are arranged to cover separate first and second regions 31 and 32 respectively in at least one surface of the magnetic body 30a (See FIG. 17). This enables that the increased thickness of resin portion around the magnetic body 30a is suppressed and a structure of the stop part 5a for holding the magnetic body 30a is strengthened. In particular, the thicknesses of the first and second resin portions 41a,41b,42a,42b on at least one surface of the magnetic body 30a can be increased, and the second resin portion 42a,42b can be interposed between the first resin portions 41a and 41b, facilitating strengthened interconnection therebetween. Compared with a case where a magnetic body is housed in a recess and this recess is closed by a lid, a structure required for securement of the lid (e.g. nail and slot with which the nail is fitted) can be omitted.

Just as a cation, when the first region 31 is covered by the first resin portion 41a, the first resin portion 41a is in direct contact with the first region 31 (there is no interspace between them). Similarly, when the second region 32 is covered by the second resin portion 42a, the second resin portion 42a is in direct contact with the second region 32 (there is no interspace between them). The first and second resin portions 41a and 42a may be formed from a same resin material but can be distinguishable based on an interface formed between the portions. The second region 32 can be formed based on contact between the magnetic body and a mold surface during a first injection molding, for example.

The same descriptions as described above would apply to the base portion 6b. The above descriptions would be read with respective replacements of the base portion 6a, the magnetic body 30a and the first and second resin portions 41a,42a with the base portion 6b, the magnetic body 30b and the first and second resin portions 41b,42b, thus overlapped descriptions would be omitted. FIGS. 1, 4 and 6 would be referred for the base portion 6b. FIG. 6 illustrates that, in each of the main surfaces 34 and 35 of the magnetic body 30b, the first region 31 is covered by a first resin portion 41b and a second region 32 is covered by a second resin portion 42b.

At least one surface of the permanent magnet 30a,30b (e.g. a main surface and/or a side surface) may be covered by the first resin portion 41a,41b and the second resin portion 42a,42b in a complemental manner. This avoids that the surface of the permanent magnet 30a,30b is not covered by the first and second resin portions and partially exposed in the stop part 5a, 5b. Alternatively, this would cancel a need to provide an additional resin portion to suppress that exposure. Preferably, in each surface (i.e. all surfaces) of the main surface 34,35 and the side surface 36 of the permanent magnet 30a,30b, the first and second regions 31,32 are covered by the first and second resin portions 41a,41b,42a,42b respectively.

The first resin portion 41a,41b may have one or more exposed surfaces that is not covered by the second resin portion 42a,42b and is exposed in the stop part 5a,5b. There is a restriction on the thickness of the resin portion around the magnetic body 30a,30b, but the first resin portion 41a,41b can be formed to be thicker and a strength of the first resin portion 41a,41b can be ensured. Note that the exposed surface of the first resin portion 41a,41b can be formed by contact between the first molded part and a mold surface during a second injection molding. From a viewpoint of suppression of defective moldings, the exposed surface of the first resin portion 41a,41b or the exposed surface of the second resin portion 42a,42b preferably extends radially with respect to the central axis of the magnetic body 30a,30b.

More detail descriptions will be presented below. As shown in FIG. 1, the bottom surface 21b of the recess 21 in the base portion 6b is configured by a combination of the exposed surface of the first resin portion 41b and the exposed surface of the second resin portion 42b. In the bottom surface 21b of the recess 21, the first resin portion 41b has an exposed surface formed in a radial (Y-shaped) pattern. This radial exposed surface has a central surface and a plurality of extending surfaces extending radially outward from the central surface. The exposed surface of the second resin portion 42b is interposed between the extending surfaces. The exposed surfaces of the second resin portion 42b are arranged at constant angular intervals in the circumferential direction about the central axis AX2 of the magnetic body 30b. As such, the bottom surface 21b of the recess 21 is formed by the radial exposed surface of the first resin portion 41b and the total 3 exposed surfaces of the second resin portion 42b.

As shown in FIG. 4, the lower surface of the base portion 6b at the opposite side of the recess 21 is configured by a combination of the exposed surface of the first resin portion 41b and the exposed surface of the second resin portion 42b. In the lower surface of the base portion 6b at the opposite side of the recess 21, the second resin portion 42b has an exposed surface that is formed in a radial (Y-shaped) pattern. The radial exposed surface has a central surface and a plurality of extending surfaces extending radially outward from the central surface. The width of the extending surface differs between radially inward position and radially outward position. As the extending surface extends away from the central surface, the width of the extending surface gradually decreases, and the width of the extending surface suddenly increases after passing a border between the radially inward position and the radially outward position. The radially outward region of the extending surface is shaped like a fan. The exposed surfaces of the first resin portion 41b is interposed between the extending surfaces. The respective exposed surfaces of the first resin portion 41b extend radially outward about the central axis AX2 of the magnetic body 30b. Therefore, it could be said that the total 3 exposed surfaces of the first resin portion 41b are formed in a radial pattern. The total 3 exposed surfaces of the first resin portion 41b are arranged at constant angular intervals in the circumferential direction about the central axis AX2 of the magnetic body 30b. As such, the lower surface of the base portion 6b is formed by the radial exposed surface of the second resin portion 42b and the total 3 exposed surfaces of the first resin portion 41b.

Note that, at the side of the lower surface of the base portion 6b, the first resin portion 41b and the second resin portion 42b are stacked on the central axis AX2 of the magnetic body 30b, that is the first resin portion 41b is covered by the second resin portion 42b on the central axis AX2 of the magnetic body 30b. This facilitates that molten resin, which will be the second resin portion 42b, smoothly flows into grooves interposed in the first resin portion 41b. As a result, a strengthened interconnection between the first and second resin portions would be achieved, and the structure for holding the magnetic body would also be strengthened. Also at the side of the upper surface of the base portion 6b, the first resin portion 41b may be covered by the second resin portion 42b similarly to the above.

As shown in FIG. 2, the top surface and/or the side surface of the axial protrusion 11 is configured by a combination of the exposed surface of the first resin portion 41a and the exposed surface of the second resin portion 42a. In the top surface of the axial protrusion 11, the second resin portion 42a has the exposed surface formed in a radial (Y-shaped) pattern. This radial exposed surface has a central surface and a plurality of extending surfaces radially outwardly extending from the central surface. The exposed surface of the first resin portion 41a is interposed between the extending surfaces. These exposed surfaces of the first resin portion 41a are arranged at constant angular intervals in the circumferential direction about the central axis AX1 of the magnetic body 30a.

In the side surface of the axial protrusion 11, the exposed surface of the first resin portion 41a and the exposed surface of the second resin portion 42a are arranged alternately in the circumferential direction with respect to the central axis AX1 of the magnetic body 30a. Each of the exposed surfaces of the first and second resin portions 41a,42a is formed in the extent to be in both of the top surface and the side surface of the axial protrusion 11. Therefore, the side wall of the axial protrusion 11 would be configured by alternate arrangement of the walls of the first resin portion 41a and the walls of the second resin portion 42a in the circumferential direction with respect to the central axis AX1 of the magnetic body 30a. There is a restriction on the thickness of the resin portion around the magnetic body 30a, but the respective resin portions can be formed to be thicker and a strength of the resin portions about the magnetic body 30a can be ensured.

Note that the first resin portion 41a and the second resin portion 42a are stacked in the central axis AX1 of the magnetic body 30a at the side of the top surface of the axial protrusion 11, that is the first resin portion 41b is covered by the second resin portion 42b. This facilitates that molten resin, which will be the second resin portion 42a, smoothly flows into grooves interposed in the first resin portion 41a. As a result, a strengthened interconnection between the first and second resin portions would be achieved, and the structure for holding the magnetic body would also be strengthened. Also, the first and second resin portions 41a,42a are stacked on the main surface of the magnetic body 30a at the opposite side of the top surface of the axial protrusion 11.

For a purpose of enhancing the magnetic attraction between the permanent magnets 30a and 30b, the resin portion may preferably be formed to be thinner on the main surface of the permanent magnet 30a at the side of the top surface of the axial protrusion 11 and similarly, the resin portion may preferably be formed to be thinner on the main surface of the permanent magnet 30b at the side of the bottom surface 21b of the recess 21. However, there is a restriction with respect to the thickness of the resin portion from a viewpoint of securement of strength. The first and second resin portions cover the first and second regions of a surface of the magnetic body respectively, as described above, facilitating that a desired thickness is ensured for the first and second resin portions regardless of the imposed restriction of the resin thickness. The first and second resin portions are not stacked redundantly, thus the increased size of the stop part is suppressed. In this instance, the first resin portion is covered by the second resin portion on the central axis of the magnetic body (the magnetic axis of the permanent magnet). This facilitates the smooth flow of the second resin portion into the grooves interposed in the first resin portion. Furthermore, upsizing of the stop part would be suppressed as the first resin portion is not covered by the second resin portion to an extent that the first resin portion does not have the exposed surface.

The shape, location, area and number of the exposed surface of the first resin portion 41a,41b may be modified variously. The same applies to the exposed surface of the second resin portion 42a,42b. The first resin portion 41a does not have an exposed surface in the upper surface of the base portion 6a but it may have an exposed surface there.

Each fastener stringer 2a and 2b (simultaneously the stop parts 5a and 5b) can be produced by an injection molding of stop part and a following magnetization of the magnetic body (i.e. application of magnetic force) as shown in FIG. 8. In the process of injection molding, problem otherwise caused when a permanent magnet is used may be avoided if a non-magnetized magnetic body is used. For example, in a case where a non-magnetized magnetic body is used, there is no possibility that it is magnetically attached to a surrounding magnetic parts while being transferred by a chuck or gripper. Also, there is no need to check if a mold is magnetic or not. With respect to the magnetization, it can be carried out by forming a strong magnetic field by electromagnets and placing in the field the stop part with the non-magnetized magnetic body embedded therein.

The injection molding can be carried out through two steps of first and second injection moldings. In the first injection molding, the magnetic bodies 30a and 30b are placed in molding cavities defined by upper and lower molds 18 and 19 as shown in FIGS. 9 and 10. Preferably, the magnetic body 30a,30b is sandwiched and held between the lower and upper molds 18 and 19, thus suppressing its displacement. Note that, appropriate clamping pressure is set for sandwiching the magnetic body 30a,30b.

The first region 31 of the surface (e.g. the main surface 34,35 and the side surface 36) of the magnetic body 30a,30b is exposed in the molding cavity. The second region 32 of the surface (e.g. the main surface 34,35 and the side surface 36) of the magnetic body 30a,30b is in contact with the mold surface of the lower mold 18 or the upper mold 19. Molten resin flows into the molding cavity through a gate and in turn, is solidified by cooling the upper and lower molds. In such a way, the first molded part 60a (see FIGS. 13-17) and the first molded part 60b (see FIGS. 18-21) are obtained. The first resin portion 41a adheres to the first region 31. The first resin portion 41a does not adhere to the second region 32. The second region 32 remains exposed as not covered by the first resin portion 41a.

In the process of the second injection molding, the first molded part 60a,60b is placed in a molding cavity defined by the upper and lower molds 18 as illustrated in FIGS. 11 and 12. Preferably, the first molded part 60a,60b is sandwiched and held between the lower mold 18 and the upper mold 19, thus suppressing its displacement. The second region 32 of the surface (e.g. the main surface 34,35 and the side surface 36) of the first molded part 60a,60b is exposed in the molding cavity. The first resin portion 41a,41b of the first molded part 60a,60b is partially in contact with the mold surface of the lower mold 18 or the upper mold 19. This contact surface of the first resin portion 41a,41b will be the exposed surface of the first resin portion 41a,41b in the stop part.

Molten resin flows into the molding cavity through a gate and in turn, is solidified by cooling the upper and lower molds. In such a way, the stop part 5a, 5b (simultaneously the fastener stringer 2a,2b with the stop part 5a,5b adhering) is obtained. The second resin portion 42a,42b adheres to the second region 32. The second resin portion 42a,42b adheres not only to the magnetic body 30a,30b but also to the first resin portion 41a,41b. Note that the side-edge portion of the fastener tape 3a,3b is also placed in the molding cavity during the second injection molding and as a result of this, the stop part 5a,5b adheres to the fastener tape 3a,3b.

With reference to the first molded part 60a illustrated in FIGS. 13-17, it would be possible to understand that each of the main surface 34,35 and the side surface 36 of the magnetic body 30a is covered by the first resin portion 41a and the second resin portion 42a in a complemental manner. Furthermore, it would be possible to understand that the first resin portion 41a is configured to receive the magnetic body 30a, and the second resin portion 42a configures a remainder of the stop part 5a other than the first resin portion 41a.

The first molded part 60a has covers 64,65 covering the main surfaces 34,35 of the magnetic body 30a, and a plurality of walls 66 covering the side surface 36 of the magnetic body 30a. The covers 64 and 65 are interconnected via the plurality of walls 66. The first region 31 is larger than the second region 32 in the main surface 34 of the magnetic body 30a. The same applies to the main surface 35 and the side surface 36 of the magnetic body 30a. By widening the first region 31 than the second region 32 as such, stability of the first molded part 60a on the lower mold 18 during the second injection molding would be enhanced. Note that, the covers 64,65 and the walls 66 adhere to the respective surfaces of the magnetic body 30a.

The covers 64 and 65 are provided with grooves 64a and 65a extending radially inward, respectively. The grooves 64a are formed to expose the main surface 34 of the magnetic body 30a in its outer peripheral area. The same applies to the grooves 65a. The first resin portion 41a is formed thinner in the center of the cover 65, allowing the grooves 65 to be in spatial communication (as a result, the Y-shaped groove is formed). Therefore, during the second injection molding, a molten resin can smoothly flow into and through the grooves 65a. Longitudinal grooves 66a are formed between adjacent walls 66 in the circumferential direction. The longitudinal groove 66a and the groove 65a are continuous, and a groove is formed which continuously extends over the side surface 36 and the main surface 35 of the magnetic body 30a. The longitudinal groove 66a is in spatial communication with a slot between interconnecting portions 62 described below, and the molten resin can more freely flow during the second injection molding.

The cover 65 has a center 65p and a plurality of extending portions 65q extending radially outward from the center 65p. The center 65p is thinner than the extending portion 65q, ensuring that the (three) grooves 65a are in spatial communication over the above-described center 65p. The extending portion 65q becomes wider as extending radially outward, i.e. has a fan-shape. Therefore, the groove 65a can extend with a substantially constant width in the radial direction.

The first molded part 60a may have an annular flange 61 protruding radially outward relative to the central axis AX1 of the magnetic body 30a. The annular flange 61 is connected to an outer rim of the cover 64 via a plurality of interconnecting portions 62. Provision of the annular flange 61 allows the first molded part 60a to be stably gripped by a chuck or gripper. The annular flange 61 may impede the flow of molten resin during the second injection molding. Therefore, a groove 63 may be formed at the inner side of the annular flange 61 (e.g. between the annular flange 61 and the cover 64). The molten resin can flow into the longitudinal groove 66a via a slot formed between interconnecting portions 62. Note that in illustrated example, the groove 64a and the groove 65a are arranged in a non-superimposed and complemental manner in the circumferential direction, but should not be limited to this. That is, the groove 64a may be positioned between the adjacent grooves 65a in the circumferential direction, and vice versa.

With reference to the first molded part 60b illustrated in FIGS. 18-21, it would be possible to understand that each of the main surface 34,35 and the side surface 36 of the magnetic body 30b is covered by the first resin portion 41b and the second resin portion 42b in a complemental manner. Furthermore, it would be possible to understand that the first resin portion 41b is configured to receive the magnetic body 30b, and the second resin portion 42b configures a remainder of the stop part 5b other than the first resin portion 41b.

The descriptions related to the first molded part 60a would mostly apply to the first molded part 60b, thus overlapping descriptions would be omitted. For example, features that the first region 31 is larger than the second region 32; the cover 64,65 is provided with grooves extending radially inward; and the cover 65 has a center 65p and a plurality of extending portions 65q would be not limited to the first molded part 60a but would similarly apply to the first molded part 60b. However, unlike the first molded part 60a, the cover 64 is shaped in a radial pattern and the widths of the extending portions 65q are substantially constant in first molded part 60b.

The cover 64 has a center 64p and a plurality of extending portions 64q extending radially outward from the center 64p. The center 64p is formed to be not thinner than the extending portion 64q, and a spatial communication of the (three) grooves 64b is interrupted by the center 64p. The extending portions 64q extend radially outward while having a constant width. Therefore, the groove 64b between the extending portions 64q would be shaped like a fan having a narrower width at radially inward area and having a wider width at radially outward area. The groove 64b, the longitudinal groove 66b and the groove 65b are in spatial communication, forming a groove that extends over the main surface 34, the side surface 36 and the main surface 35 of the magnetic body 30b.

The first molded part 60a,60b is not limited to the illustrated shape, but can be modified to other various shapes.

Method of producing a slide fastener would be appreciated by a skilled person in the art in light of the technical level at the time of filling of this application and the above descriptions, particularly in light of the method of producing the stop parts. Unique improvements in relation to the stop part of the present application would be discussed below.

With respect to a timing of magnetization of the magnetic body 30a,30b embedded in the stop part, it may preferably done after a slide fastener 1 is assembled from a pair of fastener stringers. The stop parts 5a and 5b are coupled one another in the slide fastener 1, and the base portion 6a and the base portion 6b are stacked. Therefore, the magnetic body 30a of the base portion 6a and the magnetic body 30b of the base portion 6b are aligned at upper and lower positions with a distance. In this condition, a magnetic field with a constant direction (e.g. a magnetic field in which lines of magnetic force extend along the up-down direction) is applied to the rear end portion of the slide fastener 1. Then, as would be well understood by referring to FIGS. 5 and 6, the lower half of the magnetic body 30a would be magnetized to S-pole (first pole) and the upper half of the magnetic body 30a would be magnetized to N-pole (second-pole). Similarly, the lower half of the magnetic body 30b would be magnetized to S-pole (first pole) and the upper half of the magnetic body 30b would be magnetized to N-pole (second-pole). The magnetic bodies 30a and 30b are prevented from inversely magnetized with respect to the N-pole and S-pole by applying a magnetic field having a constant direction to the rear end portion of the slide fastener 1 in the assembled state.

Note that the magnetic bodies 30a and 30b not yet magnetized have been referred to as non-magnetized magnetic bodies, but slightly magnetized magnetic bodies could be used. The non-magnetized magnetic bodies 30a and should not be limited to ones causing no magnetic field at all, but could be ones causing a magnetic field with small magnetic flux density.

Based on the above teachings, a skilled person in the art would be able to add various modifications to the respective embodiments. Reference codes in Claims are just for reference and should not be referred for the purpose of narrowly construing the scope of claims.

REFERENCE CODES

1 Slide fastener

2
a,
2
b Fastener stringer

3
a,
3
b Fastener tape

4
a,
4
b Fastener element

5
a,
5
b Stop part

6
a,
6
b Base portion

7
a,
7
b Insert

30
a,
30
b Magnetic body (the permanent magnet)

41
a,
41
b First resin portion

42
a,
42
b Second resin portion

31 First region

32 Second region

34,35 Main surface

36 Side surface

FASTENER STRINGER, SLIDE FASTENER, AND METHOD FOR PRODUCING STOPPER COMPONENT AND SLIDE FASTENER

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