EP4613142A1

EP4613142A1 - Slide fastener

Info

Publication number: EP4613142A1
Application number: EP22964498.4A
Authority: EP
Inventors: Kohei KAWARADA; Hisatomo SUGITA; Jun SHITAKA
Original assignee: YKK Corp
Current assignee: YKK Corp
Priority date: 2022-11-04
Filing date: 2022-11-04
Publication date: 2025-09-10
Also published as: CN117981952A; EP4613142A4; JP7789945B2; WO2024095482A1; CN220236213U; JPWO2024095482A1

Abstract

Each fastener elements (4,4') includes an element top portion (6,6') and an element bottom portion (5,5') which are arranged respectively on the top and bottom sides of a plane where the fastener tape (3,3') exists. The element top portion (6,6') includes a single elongate-shaped portion, the single solid portion including: a top face (61,61') that extends along a width direction of the slide fastener (1) which is orthogonal to the central line (CL) of the slide fastener (1); a front side face (62,62') that extends in the same direction; and a rear side face (63,63') that extends in the same direction. The element top portion (6,6') of the fastener element (4,4') is shaped not to stride over the central line (CL) of the slide fastener (1) in a closed state of the slide fastener (1).

Description

[Technical field]

The present disclosure is related to a slide fastener.

[Background Art]

Known are metal-made and resin-made elements as a fastener element of slide fastener, and the former ones may be swaged to a side-edge portion of fastener tape (i.e. through plastic deformation of metal) and the latter ones may be attached to a side-edge portion of fastener tape through injection molding. The metal-made elements have a higher gloss than the resin-made elements, and such appearance is more often preferred. Of course, there are some situations where the metal-made elements with a matte appearance without gloss are preferred.
Regarding the above-noted matter, the patent literature 1 discloses a resin-made element having an appearance similar to a metal-made element. The metal-made element may have sufficient attachment strength even if it has a narrower width because it is swaged to the fastener tape. In contrast, the resin-made elements are not like that. Therefore, in the PTL 1, a resin-made element includes a wider portion (see reference number 12 in Fig. 1 of PTL1) and a narrower portion (see reference number 13 in Fig. 1 of PTL1), thus balancing sufficient attachment strength and narrower element-width.
PTL2 discloses a similar resin-made element where a quadrate surface (see reference number 24a in Fig. 2 of PTL2) and a tapered surface (see reference number 24b in Fig. 2 of PTL2) are provided. Note that, as a metal-made element, known are a type shown in Fig. 19 of PTL2 (referred to as a single-sided metal-made element in PTL2) and a type shown in Figs. 20 and 21 of PTL2 (referred to as a double-sided metal-made element in PTL2).
PTL3 discloses a technique to configure a fastener element to have two divided portions to effect narrower appearance of fastener element in width.

[Citation List]

[Patent literature]

[PTL 1] International Publication No. 2010/082294
[PTL 2] International Publication No. 2016/046915
[PTL 3] International Publication No. 2019/216256

[Summary]

[Technical Problem]

The resin-made element may be configured to be narrower in width so as to have an imitated appearance of a metal-made element under a constraint of ensuring a desired attachment strength to a fastener tape and in turn, reducing a sliding resistance of slider owing to the narrower width of the resin-made elements. However, if one were obsessive on the appearance that matches a metal-made element, one or more problems may arise. For example, in a case of PTL1, if the resin-made element was configured to be further narrower in width, a tapered portion thereof (see reference numbers 13a,13b in Fig. 2 of PTL1) would also be further narrower in width accordingly. There is a possibility that one or more problems arise such as reduced mechanical strength of the tapered portion, or miniaturization and/or increased-cost of mold for injection molding. Also, in the approach of PTL3, a narrower-width appearance of fastener elements may be achieved, but it does not achieve a narrower width of the fastener element itself and as a result, it would fail to achieve reduced sliding resistance of slider.
Based on the foregoing non-limiting exemplary analysis, the present inventors have newly identified a new technical challenge to further promote the reduction in width of fastener element and to further reduce the sliding resistance of slider.

[Solution to Problem]

Slide fastener according to an aspect of the present disclosure may include: a pair of left and right fastener stringers each including a fastener tape and fastener elements attached at a given pitch to a side-edge portion of the fastener tape, each of the fastener elements including element top portion and element bottom portion which are arranged respectively on the top and bottom sides of a plane where the fastener tape exists, the element bottom portion having at least one engaging portion and at least one engaged portion; and a slider that moves forward on a central line of the slide fastener so as to alternately engage a respective fastener element of one fastener stringer of the pair of left and right fastener stringers and a respective fastener element of the other fastener stringer of the pair of left and right fastener stringers, and moves rearward on the central line of the slide fastener so as to disengage them. The element top portion of each fastener element may include a single elongate-shaped portion that includes: a top face that extends along a width direction of the slide fastener which is orthogonal to the central line of the slide fastener; a front side face that extends along the width direction of the slide fastener; and a rear side face that extends along the width direction of the slide fastener. The element top portion of each fastener element is shaped not to stride over the central line of the slide fastener in a closed state of the slide fastener where the respective fastener element of one fastener stringer of the pair of left and right fastener stringers and the respective fastener element of the other fastener stringer of the pair of left and right fastener stringers are engaged.
Slide fastener according to another aspect of the present disclosure may include: a pair of left and right fastener stringers each including a fastener tape and fastener elements attached at a given pitch to a side-edge portion of the fastener tape, each of the fastener elements including element top portion and element bottom portion which are arranged respectively on the top and bottom sides of a plane where the fastener tape exists, the element bottom portion having at least one engaging portion and at least one engaged portion; and a slider that moves forward on a central line of the slide fastener so as to alternately engage a respective fastener element of one fastener stringer of the pair of left and right fastener stringers and a respective fastener element of the other fastener stringer of the pair of left and right fastener stringers, and moves rearward on the central line of the slide fastener so as to disengage them. The element top portion of each fastener element may include: a top face that extends along a width direction of the slide fastener which is orthogonal to the central line of the slide fastener; a front side face that extends along the width direction of the slide fastener; a rear side face that extends along the width direction of the slide fastener; a first intermediate face extending along the width direction of the slide fastener at a position between the top face and the front side face; and a second intermediate face extending along the width direction of the slide fastener at a position between the top face and the rear side face, a first boundary line being between the top face and the first intermediate face, a second boundary line being between the top face and the second intermediate face. Each of the top face, the front side face and the rear side face of the element top portion of each fastener element is shaped not to stride over the central line of the slide fastener in a closed state of the slide fastener. Assuming that a first imaginary line extending in parallel to the width direction of the slide fastener and touching the first boundary line at least over a core thread provided in the side-edge portion of the fastener tape and a second imaginary line extending in parallel to the width direction of the slide fastener and touching the second boundary line at least over a core thread provided in the side-edge portion of the fastener tape are set for each of front and rear fastener elements, which are on different fastener stringers of the pair of left and right fastener stringers and being adjacent and engaged on the central line of the slide fastener, when the slide fastener is in the closed state, the element top portions of the fastener elements are shaped such that the first imaginary line of the rear fastener element and the second imaginary line of the front fastener element extend so as to form an interspace therebetween and so as not to intersect each other.
Slide fastener according to yet another aspect of the present disclosure may include: a pair of left and right fastener stringers each including a fastener tape and fastener elements attached at a given pitch to a side-edge portion of the fastener tape, each of the fastener elements including element top portion and element bottom portion which are arranged respectively on the top and bottom sides of a plane where the fastener tape exists, the element bottom portion having at least one engaging portion and at least one engaged portion; and a slider that moves forward on a central line of the slide fastener so as to alternately engage a respective fastener element of one fastener stringer of the pair of left and right fastener stringers and a respective fastener element of the other fastener stringer of the pair of left and right fastener stringers, and moves rearward on the central line of the slide fastener so as to disengage them. The element top portion of each fastener element may include: a top face that extends along a width direction of the slide fastener which is orthogonal to the central line of the slide fastener; a front side face that extends along the width direction of the slide fastener; a rear side face that extends along the width direction of the slide fastener; a first intermediate face extending along the width direction of the slide fastener at a position between the top face and the front side face; and a second intermediate face extending along the width direction of the slide fastener at a position between the top face and the rear side face, a first boundary line being between the top face and the first intermediate face, a second boundary line being between the top face and the second intermediate face. The element top portion of the fastener element has a proximal top end face positioned on a tape surface of the fastener tape, and a distal top end face positioned external of the tape surface of the fastener tape. The distal top end face of each fastener element of one fastener stringer of the pair of left and right fastener stringers and the distal top end face of each fastener element of the other fastener stringer of the pair of left and right fastener stringers are arranged alternately on the both sides of the central line of the slide fastener in the closed state of the slide fastener. Assuming that a first imaginary line extending in parallel to the width direction of the slide fastener and touching the first boundary line at least over a core thread provided in the side-edge portion of the fastener tape and a second imaginary line extending in parallel to the width direction of the slide fastener and touching the second boundary line at least over a core thread provided in the side-edge portion of the fastener tape are set for each of front and rear fastener elements, which are on different fastener stringers of the pair of left and right fastener stringers and being adjacent and engaged on the central line of the slide fastener, when the slide fastener is in the closed state, the element top portions of the fastener elements are shaped such that the first imaginary line of the rear fastener element and the second imaginary line of the front fastener element extend so as to form an interspace therebetween and so as not to intersect each other.
Any one of the above-noted embodiments may further include one or more following features alone or in any combination. Needless to say, another embodiment may be newly identified by replacing a feature of a part of either one of the above-noted embodiments with one of the following features.

[1] In the closed state of the slide fastener, the second imaginary line of the front fastener element extends so as to match or be contiguous with a third boundary line between the front side face and the first intermediate face of the rear fastener element.
[2] On each of the front and rear fastener elements, a width of the top face of the element top portion of the fastener element defined between the first and second imaginary lines is in a range of a lower bound to an upper bound, the lower bound being calculated by multiplying a value of 1/2 of a width of the element top portion by 0.8, and the upper bound being calculated by multiplying a value of 1/2 of the width of the element top portion by 1.2, wherein the width of the element top portion is defined between a bottom line of the front side face and a bottom line of the rear side face, the bottom lines being in contact with the fastener tape and extending in the width direction of the slide fastener.
[3] A third boundary line is defined between the front side face and the first intermediate face, a fourth boundary line is defined between the rear side face and the second intermediate face, and the first to fourth boundary lines are orientated substantially in parallel to each other at least over an entire width of a core thread provided in the side-edge portion of the fastener tape.
[4] The interspace is 1/3 or less of a distance between the first and second imaginary lines of one fastener element of the front and rear fastener elements, and/or the interspace is 1/5 or less of the distance between the first and second imaginary lines.
[5] The element top portion of each fastener element further includes: a first intermediate face extending along the width direction of the slide fastener at a position between the top face and the front side face; and a second intermediate face extending along the width direction of the slide fastener at a position between the top face and the rear side face, the first intermediate face is a curved surface that extends downward while curving from a first boundary line between the top face and the first intermediate face to a third boundary line between the first intermediate face and the front side face, the second intermediate face is a curved surface that extends downward while curving from a second boundary line between the top face and the second intermediate face to a fourth boundary line between the second intermediate face and the rear side face.
[6] The front side face and the rear side face are sloped, thereby the element top portion of each fastener element having a width that increases as being away from the top face. This results in the tapered shape, for example.
[7] Each of the front side face and the rear side face forms an angle in a range of 75° to 85° with a tape top surface of the fastener tape.
[8] Assuming that the rear side face of front fastener element of front and rear fastener elements and the front side face of rear fastener element of the front and rear fastener elements are translated along the width direction of the slide fastener to a common plane in the closed state of the slide fastener, the rear side face of the front fastener element and the front side face of the rear fastener element form at least segments of equal sides of an isosceles triangle having a vertex of an acute angle.
[9] The element top portion of each fastener element has a proximal top end face positioned on a tape surface of the fastener tape, and a distal top end face positioned external of the tape surface of the fastener tape, and the distal top end face of each fastener element of one fastener stringer of the pair of left and right fastener stringers and the distal top end face of each fastener element of the other fastener stringer of the pair of left and right fastener stringers are arranged alternately on the both sides of the central line of the slide fastener in the closed state of the slide fastener.
[10] The element top portion of each fastener element has a proximal top end face positioned on a tape surface of the fastener tape, and a distal top end face positioned external of the tape surface of the fastener tape, wherein assuming that the distal top end face of front fastener element of front and rear fastener elements and the distal top end face of the rear fastener element of the front and rear fastener elements are translated along the central line of the slide fastener to a common plane in the closed state of the slide fastener, the distal top end face of the front fastener element and the distal top end face of the rear fastener element form at least segments of equal sides of an isosceles triangle having a vertex of an acute angle.
[11] Each fastener element has an element central line that is parallel t o the width direction of the slide fastener, the element top portion and t he element bottom portion of each fastener element are arranged on the element central line and are shaped in symmetry with respect to the ele ment central line.
[12] The top face of the element top portion of each fastener element has a rectangular contour elongated along an element central line that is parallel to the width direction of the slide fastener.
[13] The element top portion is a substantially rectangular parallelepiped portion shaped to be elongated between a proximal top end face and a distal top end face along an element central line that is parallel to the width direction of the slide fastener, and the element bottom portion is elongated between a proximal bottom end face and a distal bottom end face along the element central line.
[14] The element top portion further includes a first intermediate face extending along the width direction of the slide fastener at a position between the top face and the front side face; and a second intermediate face extending along the width direction of the slide fastener at a position between the top face and the rear side face, in each fastener stringer of the pair of left and right fastener stringers, the distal top end face of the element top portion of the fastener element is positioned offset closer to the side-edge portion of the fastener tape than the distal bottom end face, and an intermediate surface is formed between the distal bottom end face and the distal top end face.
[15] An angle between the distal top end face and the intermediate surface is equal to an angle in a range of 90° to 100°.
[16] At least one of following conditions are satisfied: (i) the intermediat e surface has a width that gradually increases and then degreases as bei ng away from the distal top end face along the element central line; and (ii) the intermediate surface has a contour which is based a perfect circle with an arc segment cut off by the distal top end face.
[17] The element bottom portion includes a base portion having the proximal bottom end face; a head having the distal bottom end face; and a neck constricted between the base portion and the head so as to have a minimum width of fastener element.
[18] In each fastener stringer of the pair of left and right fastener stringers, the distal top end face is positioned outward of the fastener tape than a position in a direction along the element central line where the neck has the minimum element width; and/or in each fastener element of each fastener stringer of the pair of left and right fastener stringers, the distal top end face is positioned closer a position at the minimum element width of the neck relative to the distal bottom end face or a farthest position of distal bottom end face in the direction along the element central line.
[19] The element top portion of each fastener element has a proximal top end face positioned on a tape surface of the fastener tape, and a distal top end face positioned on an opposite side of the proximal top end face, the top face of the element top portion consists of total three regions of a main region, a first sloped region that is moderately sloped at a first given angle between the main region and a top edge of the proximal top end face, and a second sloped region that is moderately sloped at a second given angle between the main region and a top edge of the distal top end face.

[Advantageous Effects of Invention]

According to an aspect of the present disclosure, a reduction in width of fastener element is farther promoted to thereby further reduce a sliding resistance of slider.

[Brief Description of Drawings]

[Fig. 1] Fig. 1 is a schematic top view of a slide fastener according to an aspect of the present disclosure.
[Fig. 2] Fig. 2 is a schematic partial perspective view of the slide fastener, illustration of the slider omitted.
[Fig. 3] Fig. 3 is a schematic top view of the slide fastener, schematically depicting an engaged state of left and right fastener elements.
[Fig. 4] Fig. 4 is a left side view of the slide fastener when the slide fastener is closed, arrows pointing out locations of first and second imaginary lines DL1 and DL2.
[Fig. 5] Fig. 5 is a schematic partial cross-sectional view of the slide fastener taken along alternate long and short dashed lines IV-IV in Fig. 3.
[Fig. 6] Fig. 6 is a schematic perspective view of a fastener element attached to a side-edge portion of a fastener tape.
[Fig. 7] Fig. 7 is a schematic top view of two adjacent fastener elements attached to a side-edge portion of a fastener tape.
[Fig. 8] Fig. 8 is a schematic bottom view of the two adjacent fastener elements attached to the side-edge portion of the fastener tape.
[Fig. 9] Fig. 9 is a schematic side view of the two adjacent fastener elements attached to the side-edge portion of the fastener tape, depicting top and bottom distal end faces of the element top and bottom portions above and below an intermediate surface.
[Fig. 10] Fig. 10 is a schematic side view of the two adjacent fastener elements attached to the side-edge portion of the fastener tape (note that the right-side element is shown in cross section), depicting top and bottom proximal end faces of the element top and bottom portions above and below the fastener tape.

[Description of Embodiments]

Hereinafter, various embodiments and features would be discussed with reference to drawings. A skilled person would be able to combine respective embodiments and/or respective features without requiring excess descriptions, and would appreciate synergistic effects of such combinations. Overlapping descriptions among the embodiments would be basically omitted. Referenced drawings aim mainly for describing inventions and are simplified for the sake of convenience of preparation of drawings. The respective features should be appreciated as universal features not only effective to presently presented slide fasteners but also effective to other various slide fasteners not presented in the present specification.
In the present specification, front-rear, left-right and up-down directions which are orthogonal to one another may be referred to as terms indicative of slide-fastener-based directions. Tape width direction, tape length direction and tape thickness direction which are orthogonal to one another may be referred to as terms indicative of fastener-tape-based directions. Element central line, element width direction and element thickness direction which are orthogonal to one another may be referred to as terms indicative of fastener-element-based directions. The front-rear direction, the tape length direction and the element width direction indicate a same direction and are in parallel one another, not necessarily limited to this though. Similarly, the left-right direction, the tape width direction and the element central line indicate a same direction and are in parallel one another. Similarly, the up-down direction, the tape thickness direction and the element thickness direction indicate a same direction and are in parallel one another.
The front-rear direction matches a direction that a slider 9 moves for opening and closing a slide fastener 1, and matches an elongation direction of the slide fastener 1. The left-right direction is a direction orthogonal to the front-rear direction, and matches the width direction of the slide fastener 1. The up-down direction is a direction orthogonal to the front-rear and left-right directions. Of course, there is no need for the up-down direction to be identical to a vertical direction (gravity direction). That is, the terms indicative of directions referred in the present specification are irrelevant to the vertical direction (gravity direction).
A slide fastener 1 will be described with reference to Figs. 1-10. Fig. 1 is a schematic top view of the slide fastener 1. Fig. 2 is a schematic partial perspective view of the slide fastener 1, illustration of slider 9 omitted. Fig. 3 is a schematic top view of the slide fastener 1, schematically depicting an engaged state of left and right fastener elements 4,4'. Fig. 4 is a left side view of the slide fastener 1 when the slide fastener 1 is closed. In this state, the distal top end face 65 of each fastener element 4 of one of the paired left and right fastener stringers 2,2' and the distal top end face 65' of each fastener element 4' of the other one of the paired left and right fastener stringers 2,2' are arranged alternately on both sides of a central line CL of the slide fastener 1. Fig. 5 is a schematic partial cross-sectional view of the slide fastener 1 taken along alternate long and short dashed lines IV-IV in Fig. 3. Fig. 6 is a schematic perspective view of a fastener element 4 attached to a side-edge portion 31 of a fastener tape 3,3'. Fig. 7 is a schematic top view of two adjacent fastener elements attached to the side-edge portion 31 of a fastener tape 3,3'. Fig. 8 is a schematic bottom view of the two adjacent fastener elements 4 attached to the side-edge portion 31 of the fastener tape 3,3'. Fig. 9 is a schematic side view of the two adjacent fastener elements 4 attached to the side-edge portion 31 of the fastener tape 3,3', depicting top and bottom distal end faces 65 and 55 of the element top and bottom portions 6 and 5 above and below an intermediate surface 7,7' described hereinbelow. Fig. 10 is a schematic side view of the two adjacent fastener elements 4 attached to the side-edge portion 31 of the fastener tape 3,3' (note that the right-side element is shown in cross section), depicting top and bottom proximal end faces 64 and 54,54' of element top and bottom portions 6 and 5 above and below the fastener tape 3,3'.
The slide fastener 1 is typically a flexible longitudinal member elongated in the front-rear direction with a substantially constant width in the left-right direction. The slide fastener 1 has a pair of left and right fastener stringers 2,2', and a slider 9. The slider 9 moves forward on a central line CL of the slide fastener 1 so as to alternately engage a respective fastener element 4 of one of the paired left and right fastener stringers 2,2' and a respective fastener element 4' of the other one of the paired left and right fastener stringers 2,2', and moves rearward on the central line CL of the slide fastener 1 so as to disengage them. A slider of a common structure may be employed as the slider 9. The slider 9 has a top wing on a side of element top portion 6,6' of the fastener element 4,4' described below, a bottom wing on a side of element bottom portion 5,5' of the fastener element 4,4' described below, and a coupling pillar that interconnects the top and bottom wings. The engaged left and right fastener elements 4,4' are disengaged by the coupling pillar. The coupling pillar of the slider 9 is arranged so as to guide the element bottom portions 5,5' in each process of engagement and disengagement of the fastener elements 4,4'. It is arbitrarily if the element top portion 6,6' touches the coupling pillar of the slider 9 or not in each process of engagement and disengagement of the fastener elements 4,4', and there may be a space formed between the element top portion 6,6' and the coupling pillar.
The left and right fastener stringers 2,2' are same in the configuration (or are in mirror-symmetry) except for the fastener element arrays being offset one another at a half-pitch (Pi/2) in the front-rear direction for a purpose of engagement of the fastener elements 4,4'. Thus, descriptions focusing on the left-side fastener stringer 2 would be equally applicable to the right-side fastener stringer 2'. Components of the right-side fastener stringer 2' corresponding to components of the left-side fastener stringer 2 would be denoted by numbers with colon which are identical to the numbers designated to the components of the left-side fastener stringer 2.
The fastener stringer 2,2' has a fastener tape 3,3', and plural fastener elements 4,4' attached at a given pitch Pi to the side-edge portion 31,31' (typically a core thread 33,33') of the fastener tape 3,3'. The fastener tape 3,3' has a tape length LN3 that is greater than a tape width W3. The fastener elements 4,4' are attached one by one at a given pitch Pi to the side-edge portion 31,31' of the fastener tape 3,3' along the tape length direction of the fastener tape 3,3'. The fastener tape 3,3' is a woven fabric or knitted fabric or mixture of the two and has a high flexibility. The fastener elements 4,4' are resin-made elements attached to the side-edge portion 31,31' of the fastener tape 3,3' through injection molding. As a material of the fastener element 4,4', nylon, polyacetal, polyamide, polypropylene, polybutylene terephthalate, polycarbonate and the like may be listed, but other material may be used.
The fastener tape 3,3' has, as a tape surface, a tape top surface 36,36' and a tape bottom surface 37,37', and has a tape thickness which is substantially constant and defined by the surfaces 36,36' and 37,37'. The tape top and bottom surfaces 36,36' and 37,37' are non-flat surfaces with unevenness in accordance with woven or knitted structure of fastener tape, but these could be seen as a two-dimensional planar surface. Further, the fastener tape 3,3' may be sectioned into a side-edge portion 31,31' to which the fastener elements 4,4' are attached and a tape main portion32,32' which is a remainder other than the side-edge portion 31,31'. The side-edge portion 31,31' may be provided with a core thread 33,33'. The core thread 33,33' is elongated along the side-edge portion 31,31'. The core thread 33,33' includes: a core thread top portion protruding upward from the tape top surface 36,36' of the fastener tape 3,3'; and a core thread bottom portion protruding downward from the tape bottom surface 37,37' of the fastener tape 3,3'. One of the core thread top and bottom portions may be omitted.
The fastener element 4,4' includes an element bottom portion 5,5' and an element top portion 6,6'. The element bottom and top portions 5,5' and 6,6' are arranged on bottom and top sides with respect to a plane where the fastener tape 3,3' exists, respectively. The element top portion 6,6' may be a substantially rectangular parallelepiped portion. The element bottom portion 5,5' may have at least one engaging portion 58 and at least one engaged portion 59. The side-edge portion 31,31' and/or the core thread 33,33' of the fastener tape 3,3' is interposed between the element bottom portion 5,5' and the element top portion 6,6' in the element thickness direction. The element bottom portion 5,5' includes a portion that is in contact with and adheres to the tape bottom surface 37,37' of the fastener tape 3,3'. The element top portion 6,6' includes a portion that is in contact with and adheres to the tape top surface 36,36' of the fastener tape 3,3'. The element bottom portion 5,5' and the element top portion 6,6' are directly coupled and stacked one another on the outside of the tape surface of the fastener tape 3,3'.
The fastener element 4,4' has an element central line CX that is parallel to a width of the fastener tape 3,3'. The element central line CX is parallel to the width direction of the slide fastener 1 and positioned at the center in the width direction of the fastener element 4,4'. The element top portion 6,6' is shorter than the element bottom portion 5,5' along the element central line CX. For example, the element top portion 6,6' has a length L6 that is greater than 2/3 of a length L5 of the element bottom portion 5,5' and is lesser than 4/5 of the length L5 of the element bottom portion 5,5'.
The element top portion 6,6' may be a substantially rectangular parallelepiped portion that is shaped to be elongated between the proximal top end face 64,64' and the distal top end face 65,65' on and along the element central line CX (that has an element-width lesser than an element-length). The element bottom portion 5,5' may be shaped to be elongated between the proximal bottom end face 54,54' and the distal bottom end face 55,55' on and along the element central line CX. This results in that the fastener element 4,4' in its entirety is shaped to be elongated and has an appearance that resembles a metal-made element. Note that the proximal top end face 64,64' is positioned on the tape top surface 36,36' of the fastener tape 3,3'. The distal top end face 65,65' is positioned on the outside of the tape surface of the fastener tape 3,3'. The proximal bottom end face 54,54' is positioned on the tape bottom surface 37,37' of the fastener tape 3,3'. The distal bottom end face 55,55' is positioned on the outside of the tape surface of the fastener tape 3,3'.
Each element top portion 6,6' includes (in an exemplary embodiments, consists of) a single elongate-shaped portion including: a top face 61,61' that extends along the width direction of the slide fastener 1 (e.g. the element central line CX) which is orthogonal to the central line CL of the slide fastener 1; a front side face 62,62' that extends along the width direction of the slide fastener 1 (e.g. the element central line CX); and a rear side face 63,63' that extends along the width direction of the slide fastener 1 (e.g. the element central line CX). The element top portion 6,6' is provided on the element central line CX and extends along the element central line CX, and this would equally apply to the single elongate-shaped portion thereof. Optionally, each element top portion 6,6' further includes: a first intermediate face 66,66' that extends along the width direction of the slide fastener 1 (e.g. the element central line CX) at a position between the top face 61,61' and the front side face 62,62'; and a second intermediate face 67,67' that extends along the width direction of the slide fastener 1 (e.g. the element central line CX) at a position between the top face 61,61' and the rear side face 63,63'. The arrangement of the first and second intermediate faces 66,66',67,67' allows the fastener element 4,4' to present a narrower appearance in the width when the fastener element 4,4' is viewed from above (e.g. see Figs. 1 and 3). Note that, the single elongate-shaped portion may be the above-noted substantially rectangular parallelepiped portion.
A first boundary line L1 is defined between the top face 61,61' and the first intermediate face 66,66'; a second boundary line L2 is defined between the top face 61,61' and the second intermediate face 67,67'; a third boundary line L3 is defined between the front side face 62,62' and the first intermediate face 66,66'; and a fourth boundary line L4 is defined between the rear side face 63,63' and the second intermediate face 67,67' (see Fig. 3). The first intermediate face 66,66' may be a curved surface that extends downward while curving (e.g. at a varying or constant curvature, or in an arc) from the first boundary line L1 between the top face 61,61' and the first intermediate face 66,66' to the third boundary line L3 between the first intermediate face 66,66' and the front side face 62,62', but should not limited to this and may be a flat sloped surface. The second intermediate face 67,67' may be a curved surface that extends downward while curving (e.g. at a varying or constant curvature, or in an arc) from the second boundary line L2 between the top face 61,61' and the second intermediate face 67,67' to the fourth boundary line L4 between the second intermediate face 67,67' and the rear side face 63,63', but should not limited to this and may be a flat sloped surface.
In an exemplary embodiment, as observed in the width direction of the slide fastener 1 (see Fig. 4 for example), the first and second intermediate faces 66,66',67,67' are curved surfaces having a constant curvature, and are easily distinguishable from the top face 61,61' which is observed as a substantially flat surface. The top face 61,61' may not be a perfectly flat surface but may be curved slightly as being away from the element central line CX but, its curvature is extremely smaller than (e.g. less than 1/10 of) the curvature of the first intermediate face 66. As such, the first boundary line L1 would be drawn between the first intermediate face 66 and the top face 61,61'. The same applies to the second boundary line L2 between the top face 61,61' and the second intermediate face 67,67'. In an exemplary embodiment, the front side face 62 and the rear side face 63 are a sloped surface at a constant angle as depicted in Fig. 4 i.e. a non-curved surface. Therefore, a boundary between the first intermediate face 66 and the front side face 62 may be set at a start point of curving of the first intermediate face 66. Similarly, a boundary between the second intermediate face 67 and the rear side face 63 may be set at a start point of curving of the second intermediate face 67.
In one case, the first to fourth boundary lines L1,L2,L3,L4 are orientated substantially in parallel to each other at least over the entire width of the core thread 33 provided in the side-edge portion 31,31' of the fastener tape 3,3' (alternatively, over a main region 61a of the top face 61 of the element top portion 6 discussed below). This may be a result of that the top face 61,61', the front side face 62,62', the rear side face 63,63', and the first and second intermediate faces 66,66',67,67' run in a same direction in parallel to each other.
A distance between the first boundary line L1 and the second boundary line L2 may slightly increase as being closer to the proximal top end face 64. A distance between the third boundary line L3 and the fourth boundary line L4 may slightly increase as being closer to the proximal top end face 64,64'. A distance between the first boundary line L1 and the second boundary line L2 may slightly increase as being closer to the distal top end face 65,65'. A distance between the third boundary line L3 and the fourth boundary line L4 may slightly increase as being closer to the distal top end face 65,65'. That is, the first boundary line L1 and/or the third boundary line L3 each may have a sloped line segment that is sloped frontward as being closer to the proximal top end face 64,64' or the distal top end face 65,65'. Likewise, the second boundary line L2 and/or the fourth boundary line L4 each may have a sloped line segment that is sloped rearward as being closer to the proximal top end face 64,64' or the distal top end face 65,65'.
The element top portion 6 has a rectangular contour elongated along the element central line CX (when viewed from above). Similarly, the top face 61 of the element top portion 6 has a rectangular contour elongated along the element central line CX (when viewed from above). Owing to the elongated shapes of the element top portion 6 and the top face 61, the fastener element 4 looks like a metal-made element even though it is actually a resin-made element.
In the present embodiment, in the closed state of the slide fastener 1 in which respective ones of the fastener elements 4 of one of the paired left and right fastener stringers 2,2' and respective ones of the fastener elements 4' of the other one of the paired left and right fastener stringers 2,2' are engaged, the element top portions 6,6' of the fastener elements 4,4' are shaped not to stride over (i.e. cross) the central line CL of the slide fastener 1. In other words, the element top portions 6,6' of the fastener elements 4,4' are shaped such that none of the top faces 61,61', the front side faces 62,62', the rear side faces 63,63' and the distal top end faces 65,65' stride over (i.e. cross) the central line CL of the slide fastener 1. In this situation, it may be promoted to further facilitate narrower width of the fastener elements and reduced sliding resistance of the slider. In more particular, the appearance of fastener element 4,4' is not precisely resembled to a metal-made element and rather has a different shape from a metal-made element; however, the appearance of fastener element 4,4' is indeed resembled to a metal-made element based on a motif of a metal-made element. As a result, it is facilitated that each fastener element 4,4' has a narrower width and simultaneously a pitch of the fastener elements 4,4' becomes lesser, thereby reducing the sliding resistance of the slider 9 (i.e. lesser force is required to move the slider 9 so as to open and close the slide fastener 1). In some cases, the mechanical strength of the fastener element 4,4' is enhanced and/or simplification of the mold for injection molding of the fastener elements 4,4' may be facilitated.
By way of precaution, the narrower width of the fastener element 4,4' may result in reduced pitch Pi of the fastener elements 4,4' and reduced sliding resistance of the slider 9 for opening and closing the slide fastener 1. That is, it is facilitated that the slider 9 is moved with lesser force to open or close the slide fastener 1.
When the fastener elements 4,4' are engaged as depicted in Fig. 1, the element top portions 6,6' of the fastener elements 4,4' are arranged in a zigzag pattern on both sides of the central line CL of the slide fastener 1. Similarly, when the fastener elements 4,4' are engaged, the top faces 61 of the element top portions 6 of the left fastener elements 4 and the top faces 61 of the element top portions 6' of the right fastener elements 4' are arranged in a zigzag pattern on both sides of the central line CL of the slide fastener 1. The element top portions 6,6' have portions facing each other in the width direction of the slide fastener 1 and thus, even if the slide fastener 1 is twisted, the fastener elements 4,4' are suppressed from being disengaged owing to interference between the element top portions 6,6'.
Discussion follows with reference to Fig. 3. Assuming that a first imaginary line DL1 extending in parallel to the width direction of the slide fastener 1 and touching the first boundary line L1 at least over the core thread 33,33' provided in the side-edge portion 31,31' of the fastener tape 3,3' and a second imaginary line DL2 extending in parallel to the width direction of the slide fastener 1 and touching the second boundary line L2 at least over the core thread 33,33' provided in the side-edge portion 31,31' of the fastener tape 3,3' are set for each of front and rear fastener elements E1,E2, which are on different fastener stringers 2,2' of the pair of left and right fastener stringers 2,2' and being adjacent and engaged on the central line CL of the slide fastener 1, when the slide fastener 1 is in the closed state, the element top portions 6,6' of the fastener elements 4,4' are shaped such that the first imaginary line DL1 of the rear fastener element E2 and the second imaginary line DL2 of the front fastener element E1 extend so as to form an interspace SP therebetween and so as not to intersect each other. This allows the top faces 61,61' of the element top portions 6,6' to be sufficiently narrowed in width. The first imaginary line DL1 is located at a position where a line parallel to the width direction of the slide fastener 1 is brought into contact (inscribed, regarding the fastener element 4,4',) with the first boundary line L1 after being translated forward from the element central line CX. Similarly, the second imaginary line DL2 is located at a position where a line parallel to the width direction of the slide fastener 1 is brought into contact (inscribed, regarding the fastener element 4,4',) with the second boundary line L2 after being translated rearward from the element central line CX. Regarding the third and fourth boundary lines L3,L4, the third and fourth imaginary lines may be similarly set.
Additionally or alternatively, when the slide fastener 1 is in the closed state, the second imaginary line DL2 of the front fastener element E1 extends so as to match or be contiguous with the third boundary line L3,L3' between the front side face 62,62' and the first intermediate face 66,66' of the rear fastener element E2. This ensures an appropriate width for the top faces 61,61' of the left and right element top portions 6,6'. Additionally or alternatively, on each of the front and rear fastener elements E1,E2, a width W61 of the top face 61,61' of the element top portion 6,6' of the fastener element 4,4' defined between the first and second imaginary lines DL1 and DL2 is in a range of a lower bound to an upper bound, the lower bound being calculated by multiplying a value of 1/2 of the width W6 of the element top portion 6,6' by 0.8, and the upper bound being calculated by multiplying a value of 1/2 of the width W6 of the element top portion 6,6' by 1.2, wherein the width W6 is defined between a bottom line of the front side face 62,62' and a bottom line of the rear side face 63,63', the bottom lines being in contact with the fastener tape 3,3' and extending in the width direction of the slide fastener 1. It should be noted that, if a width of the top face 61,61' of the element top portion 6,6' on the left or right side were narrowed extremely, the fastener element 4,4' would have an appearance that is far and different from a metal-made element. As an example, the width W6 of the element top portion 6 is 1.3mm or more. The length L6 of the element top portion 6 is 2.9mm or more.
It is also possible to understand that a width of the top face 61 of the element top portion 6 of the left fastener element 4 is defined between the first and second imaginary lines DL1 and DL2, but it may also be possible to understand that it is defined between the first and second boundary lines L1 and L2. Note that, due to the sloping of the front side face 62 and the rear side face 63 of each element top portion 6, the width of the top face 61 of the element top portion 6 is lesser than the width of the element top portion 6 in the same direction.
The above-noted interspace SP may be 1/3 or less of a distance between the first and second imaginary lines DL1 and DL2 and/or may be 1/5 or more of the distance between the first and second imaginary lines DL1 and DL2 at one fastener element of the front and rear fastener elements E1,E2. By appropriately sizing the interspace SP, the top faces 61,61' would have an appropriate width.
As shown in Fig. 2, for each fastener element 4, the width W6 and the height H6 of the element top portion 6 may satisfy the following formula: 0.8<(H6/W6)<0.95. There is a possibility of reduced attachment strength of the fastener element 4 to the fastener tape 3,3' as a result of the narrower width of the element top portion 6, but a degree of the reduction of the attachment strength may be compensated by increasing the height H6 relative to the width W6. Note that, the height H6 is equal to a distance from the tape top surface 36,36' of the fastener tape 3,3' (or a plane including it) to the top face 61 of the element top portion 6 (e.g. the main region 61a described below). Note that, the PTL 1 discloses a fastener element which is designed under the condition of (H6/W6)<0.8 for a purpose of suppressing its degree of protruding.
The above-noted front side face 62,62' and the rear side face 63,63' are preferably sloped surfaces, not vertical surfaces, relative to the tape top surface 36,36' of the fastener tape 3,3'. Specifically, the front side face 62,62' is a descent slope that approaches the tape top surface 36,36' of the fastener tape 3,3' as extending forward from the top face 61,61'. Similarly, the rear side face 63,63' is a descent slope that approaches the tape top surface 36,36' of the fastener tape 3,3' as extending rearward from the top face 61,61'. For a purpose of facilitating a narrower width of the fastener element 4,4', the front side face 62,62' and the rear side face 63,63' each desirably forms an angle in a range of 75° to 85° with the tape top surface 36,36' of the fastener tape 3,3'. Further, the front side face 62,62' and the rear side face 63,63' are sloped, thereby the element top portion 6,6' of the fastener elements 4,4' each has a width that increases as being away from the top face 61,61'. As a result, each element top portion 6,6' has a tapered shape, for example.
In some cases, as shown in Fig. 4, assuming that the rear side face 63 of the front fastener element 4 and the front side face 62' of the rear fastener element 4' are translated along the width direction of the slide fastener 1 to a common plane, the rear side face 63 and the front side face 62' form at least segments of equal sides of an isosceles triangle RC having a vertex of an acute angle in the closed state of the slide fastener 1. In other words, a slant line including the rear side face 63 of the front fastener element 4 translated to a common plane and a slant line including the front side face 62' of the rear fastener element 4' translated to the common plane form equal sides of an isosceles triangle RC having a vertex of an acute angle. As such, the left and right fastener elements 4,4' have an improved symmetry (with respect to the central line CL of the slide fastener 1).
As appreciated by referring to Fig. 5, with respect to the front and rear fastener elements E1,E2 in the closed state of the slide fastener 1, assuming that the distal top end face 65 of the front fastener element 4 and the distal top end face 65' of the rear fastener element 4' are translated along the central line CL of the slide fastener 1 to a common plane, they form at least segments of equal sides of an isosceles triangle having a vertex of an acute angle. In other words, a slant line including the distal top end face 65 of the front fastener element 4 translated to a common plane and a slant line including the distal top end face 65' of the rear fastener element 4' translated to the common plane form equal sides of an isosceles triangle RC1 having a vertex of an acute angle. As such, the left and right fastener elements 4,4' have an improved symmetry (with respect to the central line CL of the slide fastener 1). Note that, the isosceles triangle RC depicted in Fig. 4 has an upwardly directed vertex, and the isosceles triangle RC1 depicted in Fig. 5 has a downwardly directed vertex. The vertex angle of the isosceles triangle RC is preferably in a range of 10° to 40° and more preferably in a range of 15° to 30°. The vertex angle of the isosceles triangle RC1 is preferably in a range of 5° to 20° and more preferably in a range of 7° to 13°.
Hereinafter, the shape of the fastener element 4,4' will be described in detail without intension of limiting. The element top portion 6,6' is a block-like portion arranged on the top side of the fastener tape 3,3', and has the top face 61,61', the front side face 62,62', the rear side face 63,63', the proximal top end face 64,64' and the distal top end face 65,65'. Typically, the present element top portion 6,6' of the present fastener element 4,4' is configured not to be engageable with an element top portion 6,6' of a fastener element 4,4' with which the present fastener element 4,4' including the present element top portion 6,6' is engaged (i.e. an engagement structure (e.g. a pair of one or more engaging portions and one or more engaged portions) is not included). The engagement function of the fastener elements 4,4' may be solely ensured by the element bottom portions 5,5'.
Each of the front side face 62,62', the rear side face 63,63', the proximal top end face 64,64' and the distal top end face 65,65' is one of side faces of the element top portion 6,6'. The front side face 62,62' and the rear side face 63,63' extend in parallel so as to be orthogonal or substantially orthogonal to the side-edge portion 31,31' of the fastener tape 3,3'. More specifically, the front side face 62,62' and the rear side face 63,63' extend along the element central line CX between the proximal top end face 64,64' and the distal top end face 65,65'. The proximal top end face 64,64' is positioned on the tape surface of the fastener tape 3,3' and in more detail, stands upward from the tape top surface 36,36' of the fastener tape 3,3'. The distal top end face 65,65' is positioned external of the tape surface of the fastener tape 3,3' and in more detail, stands upward from an intermediate surface 7,7' noted below. Note that, the distal top end face 65,65' is positioned outward of the fastener tape 3,3' viewed from the proximal top end face 64,64' and in more detail, is positioned away from the proximal top end face 64,64' in the outward direction of the fastener tape 3,3' crossing the side-edge portion 31 of the fastener tape 3,3'. Preferably, interconnection corners of respective side faces are chamfered so as to be round. The outward of fastener tape indicates, regarding a given fastener stringer, a direction directed from a position on a tape surface of the fastener tape to a position on the outside of the tape surface, and is typically orthogonal to the side-edge portion (or the core thread) of the fastener tape.
The top face 61,61' may have a rectangular contour elongated along the above-noted element central line CX. Additionally or alternatively, 1.7<(L61/W61)<2.3 may be satisfied where W61 indicates a width of the top face 61,61'; and L61 indicates a length of the top face 61,61' (see Fig. 7). The first and second intermediate faces 66,66' and 67,67' (if these were omitted, the front and rear side faces 62,62' and 63,63') are respectively coupled to the two long sides of the rectangular contour of the top face 61,61'. The proximal and distal top end faces 64,64' and 65,65' are respectively coupled to the two short sides of the rectangular contour of the top face 61,61'. Preferably, interconnection corners of the top face 61,61' with a respective surface noted above are chamfered to be round. Owing to the slope of the front side face 62, the rear side face 63,63', the proximal top end face 64 and the distal top end face 65, the top face 61 may be a reduced region than a shape (contour) of the element top portion 6 viewed from above.
The front and rear side faces 62,62' and 63,63' are preferably sloped such that the top face 61,61' appears narrower in width. That is, as seen in Figs. 9 and 10, the front side face 62,62' is sloped so as to be away from the element central line CX as extending downward from the top face 61,61' (or the first intermediate face 66,66'), and the rear side face 63,63' is sloped so as to be away from the element central line CX as extending downward from the top face 61,61' (or the second intermediate face 67,67'). As a result, the element top portion 6,6' is shaped to be a trapezoid when viewed in the direction along the element central line CX. Here, the top face 61,61' matches the upper base of the trapezoid.
The proximal top end face 64,64' is sloped so as to be away from the distal top end face 65,65' as extending downward from the top face 61,61', and the distal top end face 65,65' is sloped so as to be away from the proximal top end face 64,64' as extending downward from the top face 61,61' (see Fig. 5). Assuming that a plane where the tape top surface 36,36' of the fastener tape 3,3' exists is set as a base, preferably, an angle θ₆₄ between the plane and the proximal top end face 64 (see Fig. 5) is greater than an angle θ₆₂ between the plane and the front side face 62 (see Fig. 10) and is greater than an angle θ₆₃ between the plane and the rear side face 63,63' (see Fig. 10). The same applies to an angle θ₆₅ between the plane and the distal top end face 65. Owing to the relatively moderate sloping of the angle θ₆₂ and the angle θ₆₃, the appearance of elongated shape of the element top portion 6 and the attachment strength of the fastener element 4 are well balanced.
The top face 61,61' of the element top portion 6,6' consists of a two-dimensional single face or a two-dimensional series of faces. In the latter case, as shown in Fig. 4, the top face 61,61' may consist of total three regions of a main region 61a, a first sloped region 61b and a second sloped region 61c (see Fig. 5). The first sloped region 61b is moderately sloped at a first given angle θ_61b between the main region 61a and the top edge of the proximal top end face 64. The second sloped region 61c is moderately sloped at a second given angle θ_61c between the main region 61a and the top edge of the distal top end face 65.
The main region 61a may be a flat surface that is oriented in parallel to the tape top surface 36,36' of the fastener tape 3,3' or a plane including the same. The first given angle θ_61b may be an angle between a plane where the main region 61a exists and the first sloped region 61b. The second given angle θ_61c may be an angle between the plane where the main region 61a exists and the second sloped region 61c. Advantageously, the second given angle θ_61c is lesser than the first given angle θ_61b. This facilitates that the distal top end face 65 has a sufficient height, suppressing the fastener elements 4,4' from being disengaged as the element top portions 6,6' interfere with one another when the slide fastener 1 is twisted, for example.
Further description follows with reference to Fig. 5. The proximal top end face 64 extends upward steeply between positions P1 and P2. The top face 61 extends between the positions P2 and P5. In more detail, the first sloped region 61b extends upward moderately from the position P2 toward the position P3. The main region 61a extends horizontally between the positions P3 and P4. The second sloped region 61c extends downward moderately from the position P4 toward the position P5. The distal top end face 65 extends downward steeply between the positions P5 and P6. Each of the distance between the positions P1 and P2 and the distance between the positions P5 and P6 is sufficiently lesser than the distance between the positions P2 and P5.
As discussed above, the element bottom portion 5,5' is shaped so as to be elongated along the element central line CX and between the proximal bottom end face 54,54' and the distal bottom end face 55,55' and so as to have at least one engaging portion 58 and at least one engaged portion 59 between the proximal bottom end face 54,54' and the distal bottom end face 55,55'. The present element bottom portion 5 is typically configured to be engaged with two respective element bottom portions 5',5' of two fastener elements 4',4' with which the present fastener element 4 including the present element bottom portion 5 is engaged. For this purpose, the engaging portion 58 and the engaged portion 59 are appropriately shaped. The engaging portion 58 protrudes along the central line CL of the slide fastener 1 or an axial line parallel to it, typically. The engaged portion 59 is recessed along the central line CL of the slide fastener 1 or an axial line parallel to it, typically.
The proximal bottom end face 54,54' stands downward from the tape bottom surface 37 of the fastener tape 3,3'. The distal bottom end face 55,55' positioned away from the proximal bottom end face 54,54' in the outward direction of the fastener tape 3,3' across the side-edge portion 31 of the fastener tape 3,3' (i.e. positioned external of tape surface of the fastener tape 3,3').
The distal bottom end face 55,55' may be a curved surface that protrudes most along the element central axis CX of the fastener element 4. The distal bottom end face 55,55' is sloped downward steeply from the position P8 toward the position P7 as shown in Fig. 5. The distal bottom end face 55,55' may include a moderate curbed surface in the vicinity of the position P7.
In some cases, the distal top end face 65 is positioned offset closer to the side-edge portion 31 (or the core thread 33) than the distal bottom end face 55,55', and an intermediate surface 7,7' is formed between the distal bottom end face 55,55' and the distal top end face 65. This allows one to place a priority on the design of narrowing the width of the element top portion 6,6'. In connection with this, owing to the narrower width of the element top portion 6,6', the appearance of the fastener element 4 which is similar to a metal-made element may be ensured. Accordingly, provided be the narrow-width fastener elements 4 which look like metal-made elements based on a motif of a metal-made element.
The intermediate surface 7,7' may be a flat surface orthogonal to the thickness direction of the fastener element, and may be positioned in a same plane as the fastener tape 3,3', not necessarily limited to this though. Preferably, the intermediate surface 7,7' is positioned in a same plane as the tape top surface 36,36' of the fastener tape 3,3' or is positioned in a plane that is closer to the tape top surface 36,36' than the tape bottom surface 37 of the fastener tape 3,3'. In this case, it is ensured that the element bottom portion 5,5' under the intermediate surface 7,7' has a sufficient thickness, enhancing the engagement strength of the fastener elements 4,4'. Typically, an angle θ1 between the distal top end face 65 and the intermediate surface 7,7' is equal to an angle in a range of 90° to 100° (see Fig. 5). An angle θ₅₅ between the distal bottom end face 55,55' and the intermediate surface 7,7' is equal to an angle in a range of 80° to 90°(see Fig. 5). It may be possible to form the intermediate surface 7,7' as a sloped surface or non-flat surface.
The intermediate surface 7,7' may have a top view shape (or an exposed shape thereof when the fastener elements 4,4' are disengaged) which depends on the engagement structure of the element bottom portions 5,5'. Typically, (i) the intermediate surface 7,7' has a width that gradually increases and then degreases as being away from the distal top end face 65 along the element central line CX; and/or the intermediate surface 7,7' has a contour which is based a perfect circle with an arc segment cut off by the distal top end face 65.
As would be appreciated from Fig. 3, the intermediate surface 7 of the fastener element 4 may include two placement region 71 on which the element top portions 6',6' (e.g. shoulders 8 noted below) of two fastener element 4',4' of engagement partners are placed respectively, and an intermediate region 72 interposed between these two placement regions 71. The intermediate region 72 may have an area which is in a range of 0.5 to 1.5 times a total value of areas of the two placement regions 71. The same description applies to the fastener element 4'. When the fastener elements 4,4' are engaged, the intermediate region 72,72' can be visible (when viewed from above). At this instance, the intermediate region 72,72' is positioned on the deeper side between the element top portions 6,6' (and between the top faces 61,61' thereof) and is less noticeable.
In some cases including the illustrated example, the element bottom portion 5 has a base portion 51 having the proximal bottom end face 54; a head 53 having the distal bottom end face 55; and a neck 52 constricted between the base portion 51 and the head 53 so as to have a minimum width of fastener element. The head 53 includes two engaging portions 58, as the at least one engaging portion 58, which protrude in the opposite directions along the tape length direction (see Fig. 6). The neck 52 includes two engaged portions 59, as the at least one engaged portion 59, which are recessed so as to form the constricted shape of the neck 52. The same description applies to the element bottom portion 5'.
The base portion 51 is formed to have a width that is substantially equal to a width of the element top portion 6,6'. That is, the width W51 of the base portion 51 is equivalent to the width W6 of the element top portion 6,6'. Therefore, the pitch P1 of the fastener elements 4 can be determined based on the structure of the element bottom portion 5,5'. Note that, the length of the base portion 51 along the element central line CX is lesser than the length L6 of the element top portion 6,6'. The proximal bottom end face 54,54' is positioned on the opposite side of the proximal top end face 64,64' of the element top portion 6,6' such that the fastener tape 3,3' is interposed therebetween. The base portion 51 has two side faces 512,513 that are provided to be orthogonal to the width direction of fastener element, each of two side faces 512,513 extending along the element central line CX to cross the core thread 33 (see Fig. 8).
The neck 52 has a width W52 that is the narrowest in the element bottom portion 5,5' (see Fig. 8). The head 53 has a width W53 that is the widest in the element bottom portion 5,5' except for the base portion 51. The element bottom portion 5,5' has a width that gradually decreases until reaching the width W52 as extending in the outward direction of the fastener tape from an intermediate position between the base portion 51 and the neck 52 (i.e. from a start position of the neck) and that gradually increases until reaching the width W53 after passing the width W52. As a result, the neck 52 is shaped to have a constricted portion and is shaped such that the each engaged portion 59 has a semi-cylindrical accommodation space. The head 53 has a width that decreases from the width W53 in the outward direction of fastener tape. The bottom surfaces of the base portion 51, the neck 52 and the head 53 are formed in the same plane so that one bottom surface 56 is formed for the element bottom portion 5,5'. The side faces of the base portion 51, the neck 52 and the head 53 are formed continuously to define one contour. As depicted in Fig. 5, the base portion 51 adheres to the core thread 33, having a width defined between the positions P11 and P12, and to a portion of the fastener tape 3,3' in the vicinity of the core thread 33.
The two respective engaging portions 58 are sectioned by the element central line CX of the fastener element 4 and/or may be in mirror symmetry with respect to the element central line CX (i.e. they may be semi-cylindrical portions). Similarly, the two engaged portions 59 are sectioned by the element central line CX of the fastener element 4 and/or may be in mirror symmetry with respect to the element central line CX (i.e. they may be portions having a semi-cylindrical accommodation space).
The two engaged portions 59 may be respectively covered at least partially from above by the two shoulders 8 of the element top portions 6,6' (see Fig. 6). The shoulders 8 are arranged on the both sides of the neck 52 when viewed from a position under the fastener element 4 (see Fig. 8). When the left and right fastener elements 4,4' are engaged, the head 53 of the fastener element 4 on one side of the left and right sides is inserted and held between the necks 52' of adjacent fastener elements 4' on the other side of the left and right sides. In this situation, the head 53 is arranged directly under the shoulders 8' of those fastener elements 4' and thus is restricted from upward and downward displacement. That is, the shoulder of the fastener element 4 functions as a portion that restricts the displacement of the fastener element 4' of the engagement partner. Advantageously, the shoulder 8 forms a portion of the block-like element top portion 6,6', and does not have a distinguishable shape as a shoulder (when the element top portion 6,6' is viewed from above).
The distal top end face 65 is positioned outward of the fastener tape 3,3' than a position in the direction along the element central line CX where the neck 52 has the minimum element width W52 (see Figs. 5-8). This allows the element top portion 6,6' to be formed to be elongate and/or allows the shoulders 8 to have a sufficient area. Additionally or alternatively, the distal top end face 65 is positioned closer to the position at the minimum element width W52 of the neck 52 relative to the distal bottom end face 55,55' or the farthest position thereof in the direction along the element central line CX. That is, as shown in Fig. 8, the length L8 is lesser than the length L9. In this case, it is ensured that the intermediate surface 7,7' has a sufficient length L7 (See Fig. 7). Note that, by increasing the length L7 of the intermediate surface 7,7', the left and right fastener elements 4,4' would be more stably engaged.
Method of producing the slide fastener 1 would be apparent for a skilled person in view of the above descriptions and thus omitted. A cavity shape of a mold for injection molding of the fastener element 4 is simplified owing to the element top portion 6,6' of a relatively simple shape. The slopes of the side faces (e.g. the front side face 62 and the rear side face 63) of the element top portion 6,6' serve as a draft for the fastener element 4 out of the mold cavity. A gate may be positioned at a location (e.g. the distal bottom end face 55,55') other than the cavity surface for molding the top face 61,61' of the element top portion 6,6'. This ensures that the top face 61,61' has a high flatness and/or smoothness. The distal bottom end face 55,55' may have a gate mark. It is preferable that the cavity surface of the mold has a high smoothness so that the external surface of the fastener element 4 has a high smoothness.
A metal foil may be attached onto the top face 61,61' to enhance the degree of luster. In this case, it would be possible to ensure the light reflection across wider angular range owing to the first and second sloped regions 61b and 61c. Note that, this feature would be equally applicable to a case where the metal foil is not provided.
Based on the above-described teachings, those skilled in the art may make various changes to each embodiment. The codes incorporated in the claims are for reference only and should not be referred to for a purpose of limiting the scope of claims.

[Reference codes]

1: : Slide fastener
2: : Fastener stringer
3: : Fastener tape
4: : Fastener element
5: : Element bottom portion
6: : Element top portion
7: : Intermediate surface
8: : Shoulder
9: : Slider
51: : Base portion
52: : Neck
53: : Head
54: : Proximal bottom end face
55: : Distal bottom end face
58: : Engaging portion
59: : Engaged portion
61: : Top face
61a: : Main region
61b: : First sloped region
61c: : Second sloped region
62: : Front side face
63: : Rear side face
64: : Top proximal end surface
65: : Top distal end surface
71: : Placement region
72: : Intermediate region

Claims

A slide fastener (1) comprising:
a pair of left and right fastener stringers (2,2') each including a fastener tape (3,3') and fastener elements (4,4') attached at a given pitch (Pi) to a side-edge portion (31,31') of the fastener tape (3,3'), each of the fastener elements (4,4') including element top portion (6,6') and element bottom portion (5,5') which are arranged respectively on the top and bottom sides of a plane where the fastener tape (3,3') exists, the element bottom portion (5,5') having at least one engaging portion (58) and at least one engaged portion (59); and

a slider (9) that moves forward on a central line (CL) of the slide fastener (1) so as to alternately engage a respective fastener element (4) of one fastener stringer of the pair of left and right fastener stringers (2,2') and a respective fastener element (4') of the other fastener stringer of the pair of left and right fastener stringers (2,2'), and moves rearward on the central line (CL) of the slide fastener (1) so as to disengage them, wherein

the element top portion (6,6') of each fastener element (4,4') comprises a single elongate-shaped portion that includes: a top face (61,61') that extends along a width direction of the slide fastener (1) which is orthogonal to the central line (CL) of the slide fastener (1); a front side face (62,62') that extends along the width direction of the slide fastener (1); and a rear side face (63,63') that extends along the width direction of the slide fastener (1),

the element top portion (6,6') of each fastener element (4,4') is shaped not to stride over the central line (CL) of the slide fastener (1) in a closed state of the slide fastener (1) where the respective fastener element (4) of one fastener stringer of the pair of left and right fastener stringers (2,2') and the respective fastener element (4') of the other fastener stringer of the pair of left and right fastener stringers (2,2') are engaged.
The slide fastener of Claim 1, in which the element top portion (6,6') of each fastener element (4,4') further includes a first intermediate face (66,66') extending along the width direction of the slide fastener (1) at a position between the top face (61,61') and the front side face (62,62'); and a second intermediate face (67,67') extending along the width direction of the slide fastener (1) at a position between the top face (61,61') and the rear side face (63,63'), a first boundary line (L1) being between the top face (61,61') and the first intermediate face (66,66'), a second boundary line (L2) being between the top face (61,61') and the second intermediate face (67,67'), wherein
assuming that a first imaginary line (DL1) extending in parallel to the width direction of the slide fastener (1) and touching the first boundary line (L1) at least over a core thread (33,33') provided in the side-edge portion (31,31') of the fastener tape (3,3') and a second imaginary line (DL2) extending in parallel to the width direction of the slide fastener (1) and touching the second boundary line (L2) at least over a core thread (33,33') provided in the side-edge portion (31,31') of the fastener tape (3,3') are set for each of front and rear fastener elements (E1,E2), which are on different fastener stringers (2,2') of the pair of left and right fastener stringers (2,2') and being adjacent and engaged on the central line (CL) of the slide fastener (1), when the slide fastener (1) is in the closed state,

the element top portions (6,6') of the respective fastener elements (4,4') are shaped such that the first imaginary line (DL1) of the rear fastener element (E2) and the second imaginary line (DL2) of the front fastener element (E1) extend so as to form an interspace (SP) therebetween and so as not to intersect each other.
The slide fastener of Claim 2, wherein in the closed state of the slide fastener (1), the second imaginary line (DL2) of the front fastener element (E1) extends so as to match or be contiguous with a third boundary line (L3) between the front side face (62,62') and the first intermediate face (66,66') of the rear fastener element (E2).
The slide fastener of Claim 2 or 3, wherein on each of the front and rear fastener elements (E1,E2), a width (W61) of the top face (61,61') of the element top portion (6,6') of the fastener element (4,4') defined between the first and second imaginary lines (DL1,DL2) is in a range of a lower bound to an upper bound,
the lower bound being calculated by multiplying a value of 1/2 of a width (W6) of the element top portion (6,6') by 0.8, and

the upper bound being calculated by multiplying a value of 1/2 of the width (W6) of the element top portion (6,6') by 1.2, wherein

the width (W6) of the element top portion (6,6') is defined between a bottom line of the front side face (62,62') and a bottom line of the rear side face (63,63'), the bottom lines being in contact with the fastener tape (3,3') and extending in the width direction of the slide fastener (1).
The slide fastener of any one of Claims 2-4 wherein a third boundary line (L3) is defined between the front side face (62,62') and the first intermediate face (66,66'),
a fourth boundary line (L4) is defined between the rear side face (63) and the second intermediate face (67,67'), and

the first to fourth boundary lines (L1,L2,L3,L4) are orientated substantially in parallel to each other at least over an entire width of a core thread (33,33') provided in the side-edge portion (31,31') of the fastener tape (3,3').
The slide fastener of any one of Claims 2-5, wherein the interspace (SP) is 1/3 or less of a distance between the first and second imaginary lines (DL1,DL2) of one fastener element of the front and rear fastener elements (E1,E2).
The slide fastener of Claim 6, wherein the interspace (SP) is 1/5 or less of the distance between the first and second imaginary lines (DL1,DL2).
The slide fastener of any one of Claims 1-7, wherein the element top portion (6,6') of each fastener element (4,4') further includes:
a first intermediate face (66,66') extending along the width direction of the slide fastener (1) at a position between the top face (61,61') and the front side face (62,62'); and a second intermediate face (67,67') extending along the width direction of the slide fastener (1) at a position between the top face (61,61') and the rear side face (63,63'),

the first intermediate face (66,66') is a curved surface that extends downward while curving from a first boundary line (L1) between the top face (61,61') and the first intermediate face (66,66') to a third boundary line (L3) between the first intermediate face (66,66') and the front side face (62,62'),

the second intermediate face (67,67') is a curved surface that extends downward while curving from a second boundary line (L2) between the top face (61,61') and the second intermediate face (67,67') to a fourth boundary line (L4) between the second intermediate face (67,67') and the rear side face (63,63').
The slide fastener of any one of Claims 1-8, wherein the front side face (62,62') and the rear side face (63) are sloped, thereby the element top portion (6,6') of each fastener element (4,4') having a width that increases as being away from the top face (61,61').
The slide fastener of any one of Claims 1-9, wherein each of the front side face (62,62') and the rear side face (63) forms an angle in a range of 75° to 85° with a tape top surface (36) of the fastener tape (3,3').
The slide fastener of any one of Claims 1-10, wherein assuming that the rear side face (63) of front fastener element (E1) of front and rear fastener elements (E1,E2) and the front side face (62') of rear fastener element (E2) of the front and rear fastener elements (E1,E2) are translated along the width direction of the slide fastener (1) to a common plane in the closed state of the slide fastener (1),
the rear side face (63) of the front fastener element (E1) and the front side face (62') of the rear fastener element (E2) form at least segments of equal sides of an isosceles triangle having a vertex of an acute angle.
The slide fastener of any one of Claims 1-11, wherein the element top portion (6,6') of each fastener element (4,4') has a proximal top end face (64,64') positioned on a tape surface of the fastener tape (3,3'), and a distal top end face (65,65') positioned external of the tape surface of the fastener tape (3,3'), and
the distal top end face (65,65') of each fastener element (4) of one fastener stringer of the pair of left and right fastener stringers (2,2') and the distal top end face (65') of each fastener element (4') of the other fastener stringer of the pair of left and right fastener stringers (2,2') are arranged alternately on the both sides of the central line (CL) of the slide fastener (1) in the closed state of the slide fastener (1).
The slide fastener of any one of Claims 1-12 in which the element top portion (6,6') of each fastener element (4,4') has a proximal top end face (64,64') positioned on a tape surface of the fastener tape (3,3'), and a distal top end face (65,65') positioned external of the tape surface of the fastener tape (3,3'), wherein
assuming that the distal top end face (65) of front fastener element (E1) of front and rear fastener elements (E1,E2) and the distal top end face (65') of the rear fastener element (E2) of the front and rear fastener elements (E1,E2) are translated along the central line (CL) of the slide fastener (1) to a common plane in the closed state of the slide fastener (1), the distal top end face (65) of the front fastener element (E1) and the distal top end face (65') of the rear fastener element (E2) form at least segments of equal sides of an isosceles triangle having a vertex of an acute angle.
The slide fastener of any one of Claims 1-13, wherein each fastener element (4,4') has an element central line (CX) that is parallel to the width direction of the slide fastener (1), and
the element top portion (6,6') and the element bottom portion (5,5') of each fastener element (4,4') are arranged on the element central line (CX) and are shaped in symmetry with respect to the element central line (CX).
The slide fastener of any one of Claims 1-14, wherein the top face (61,61') of the element top portion (6,6') of each fastener element (4,4') has a rectangular contour elongated along an element central line (CX) that is parallel to the width direction of the slide fastener (1).
The slide fastener of any one of Claims 1-15, wherein the element top portion (6,6') is a substantially rectangular parallelepiped portion shaped to be elongated between a proximal top end face (64,64') and a distal top end face (65,65') along an element central line (CX) that is parallel to the width direction of the slide fastener (1), and
the element bottom portion (5) is elongated between a proximal bottom end face (54) and a distal bottom end face (55) along the element central line (CX).
The slide fastener of Claim 16, wherein the element top portion (6,6') further includes a first intermediate face (66,66') extending along the width direction of the slide fastener (1) at a position between the top face (61,61') and the front side face (62,62'); and a second intermediate face (67,67') extending along the width direction of the slide fastener (1) at a position between the top face (61,61') and the rear side face (63,63'), in each fastener stringer (2,2') of the pair of left and right fastener stringers (2,2'), the distal top end face (65,65') of the element top portion (6,6') of the fastener element (4,4') is positioned offset closer to the side-edge portion (31,31') of the fastener tape (3,3') than the distal bottom end face (55), and an intermediate surface (7,7') is formed between the distal bottom end face (55) and the distal top end face (65,65').
The slide fastener of Claim 17, wherein an angle between the distal top end face (65,65') and the intermediate surface (7,7') is equal to an angle in a range of 90° to 100°.
The slide fastener of Claim 17 or 18, wherein at least one of following conditions are satisfied:
(i) the intermediate surface (7,7') has a width that gradually increases and then degreases as being away from the distal top end face (65,65') along the element central line (CX); and

(ii) the intermediate surface (7,7') has a contour which is based a perfect circle with an arc segment cut off by the distal top end face (65,65').
The slide fastener of any one of Claims 16-19 in which the element bottom portion (5) includes a base portion (51) having the proximal bottom end face (54); a head (53) having the distal bottom end face (55); and a neck (52) constricted between the base portion (51) and the head (53) so as to have a minimum width of fastener element,
in each fastener stringer (2,2') of the pair of left and right fastener stringers (2,2'), the distal top end face (65,65') is positioned outward of the fastener tape (3,3') than a position in a direction along the element central line (CX) where the neck (52) has the minimum element width; and/or

in each fastener element (4,4') of each fastener stringer (2,2') of the pair of left and right fastener stringers (2,2'), the distal top end face (65,65') is positioned closer a position at the minimum element width (W52) of the neck (52) relative to the distal bottom end face (55) or a farthest position of distal bottom end face (55) in the direction along the element central line (CX).
The slide fastener of any one of Claims 1-20, wherein the element top portion (6,6') of each fastener element (4,4') has a proximal top end face (64,64') positioned on a tape surface of the fastener tape (3,3'), and a distal top end face (65,65') positioned on an opposite side of the proximal top end face (64,64'),
the top face (61,61') of the element top portion (6) consists of total three regions of a main region (61a), a first sloped region (61b) that is moderately sloped at a first given angle between the main region (61a) and a top edge of the proximal top end face (64), and a second sloped region (61c) that is moderately sloped at a second given angle between the main region (61a) and a top edge of the distal top end face (65,65').