JP7789945B2 - Slide fastener - Google Patents

Description

The present disclosure relates to a slide fastener.

Metal elements and resin elements are known as fastener elements for slide fasteners; the former are attached to the side edge of the fastener tape by crimping (i.e., through plastic deformation of the metal), while the latter are attached to the side edge of the fastener tape by injection molding. Metal elements have a higher gloss than resin elements, and this appearance is often preferred. Of course, there are also cases where a matte, non-glossy appearance is preferred even for metal elements.

Regarding the above points, Patent Document 1 discloses a resin element that looks similar to a metal element. Metal elements have sufficient attachment strength even when they are narrow because they are tightened against the fastener tape. Resin elements, on the other hand, do not. Therefore, Patent Document 1 achieves both sufficient attachment strength and a narrow element width by providing a relatively thick portion (see reference numeral 12 in Figure 1 of Patent Document 1) and a tapered portion (see reference numeral 13 in Figure 1 of Patent Document 1).

A similar resin element is also disclosed in Patent Document 2. In Patent Document 2, a quadrilateral surface (see reference numeral 24a in Figure 2 of Patent Document 2) and a tapered surface (see reference numeral 24b in Figure 2 of Patent Document 2) are provided. Known metal elements include the one shown in Figure 19 of Patent Document 2 (referred to as a single-sided metal element in Patent Document 2) and the one shown in Figures 20 and 21 of Patent Document 2 (referred to as a double-sided metal element in Patent Document 2).

Patent document 3 discloses providing two divided sections to one fastener element to make the fastener element appear narrower.

International Publication No. 2010/082294 International Publication No. 2016/046915 International Publication No. 2019/216256

Under the constraint of ensuring the desired attachment strength to the fastener tape, narrowing the resin element allows it to more closely resemble the appearance of a metal element, and the resulting narrowing can reduce the sliding resistance of the slider. However, insisting on matching the appearance with the metal element can lead to one or more problems. For example, in the case of Patent Document 1, narrowing the resin element also results in the tapered portion (see references 13a and 13b in Figure 2 of the same document) becoming even narrower. This can lead to one or more problems, such as a decrease in the mechanical strength of the tapered portion, or the need for a more detailed and/or more expensive injection molding die. Furthermore, the method of Patent Document 3 can make the fastener element appear narrower, but does not achieve a narrower fastener element itself, resulting in an inability to reduce the sliding resistance of the slider.

Based on the consideration of the above non-limiting examples, the inventors of the present application have discovered a new problem: to further reduce the sliding resistance of the slider by further reducing the width of the fastener element.

A slide fastener according to one aspect of the present disclosure comprises a pair of left and right fastener stringers, each of which includes a fastener tape and a plurality of fastener elements attached to the side edges of the fastener tape at a predetermined pitch. Each fastener element includes a lower element portion and an upper element portion respectively disposed above and below the plane of the fastener tape, the lower element portion having at least one engaging portion and at least one engaged portion. The slide fastener also includes a slider that advances along the center line of the slide fastener to alternately engage the individual fastener elements included in one of the pair of fastener stringers with the individual fastener elements included in the other of the pair of fastener stringers, and that moves backward along the center line of the slide fastener to disengage them. The upper element portion of each fastener element includes a single elongated portion that includes an upper surface extending along the width direction of the slide fastener, which is perpendicular to the center line of the slide fastener, a front side surface extending along the width direction of the slide fastener, and a rear side surface extending along the width direction of the slide fastener. In a closed state of the slide fastener in which an individual fastener element included in one of a pair of left and right fastener stringers is engaged with an individual fastener element included in the other of the pair of left and right fastener stringers, the upper part of each fastener element is shaped so as not to straddle the center line of the slide fastener.

A slide fastener according to another aspect of the present disclosure comprises a pair of left and right fastener stringers, each of which includes a fastener tape and a plurality of fastener elements attached to the side edge of the fastener tape at a predetermined pitch, each of which includes a lower element portion and an upper element portion respectively provided below and above the plane on which the fastener tape is located, the lower element portion having at least one engaging portion and at least one engaged portion, and a slider that moves forward on the center line of the slide fastener to alternately engage the individual fastener elements included in one of the pair of left and right fastener stringers with the individual fastener elements included in the other of the pair of left and right fastener stringers, and moves backward on the center line of the slide fastener to disengage them. The element upper part of each fastener element includes an upper surface extending along the width direction of the slide fastener which is perpendicular to the center line of the slide fastener, a front side surface extending along the width direction of the slide fastener, a rear side surface extending along the width direction of the slide fastener, a first intermediate surface extending along the width direction of the slide fastener between the upper surface and the front side surface, and a second intermediate surface extending along the width direction of the slide fastener between the upper surface and the rear side surface, wherein a first boundary line is defined between the upper surface and the first intermediate surface, and a second boundary line is defined between the upper surface and the second intermediate surface. When the slide fastener is in a closed state, the upper surface, front side surface, and rear side surface of the element upper part of each fastener element are shaped so as not to straddle the center line of the slide fastener. In the closed state of the slide fastener, in each of the front and rear fastener elements provided on different fastener stringers of a pair of left and right fastener stringers and adjacently engaged on the center line of the slide fastener, when a first imaginary line is set that is tangent to the first boundary line at least on the core string provided on the side edge of the fastener tape and extends parallel to the width direction of the slide fastener, and a second imaginary line that is tangent to the second boundary line at least on the core string provided on the side edge of the fastener tape and extends parallel to the width direction of the slide fastener, the upper part of the fastener element is shaped so that the first imaginary line of the rear fastener element and the second imaginary line of the front fastener element extend with a gap between them without intersecting.

A slide fastener according to a further aspect of the present disclosure comprises a pair of left and right fastener stringers, each of which includes a fastener tape and a plurality of fastener elements attached to the side edge of the fastener tape at a predetermined pitch, each of which includes a lower element portion and an upper element portion respectively provided below and above the plane on which the fastener tape is located, the lower element portion having at least one engaging portion and at least one engaged portion, and a slider that moves forward on the center line of the slide fastener to alternately engage the individual fastener elements included in one of the pair of left and right fastener stringers with the individual fastener elements included in the other of the pair of left and right fastener stringers, and moves backward on the center line of the slide fastener to disengage them. The element upper part of each fastener element includes an upper surface extending along the width direction of the slide fastener perpendicular to the center line of the slide fastener, a front side surface extending along the width direction of the slide fastener, a rear side surface extending along the width direction of the slide fastener, a first intermediate surface extending along the width direction of the slide fastener between the upper surface and the front side surface, and a second intermediate surface extending along the width direction of the slide fastener between the upper surface and the rear side surface, and a first boundary line is defined between the upper surface and the first intermediate surface, and a second boundary line is defined between the upper surface and the second intermediate surface. The element upper part of the fastener element has an upper base end surface located on the tape surface of the fastener tape and an upper tip surface located outside the tape surface of the fastener tape. When the slide fastener is in a closed state, the upper tip surfaces of the individual fastener elements included in one of the pair of left and right fastener stringers and the upper tip surfaces of the individual fastener elements included in the other of the pair of left and right fastener stringers are arranged alternately on both sides of the center line of the slide fastener. In the closed state of the slide fastener, in each of the front and rear fastener elements provided on different fastener stringers of a pair of left and right fastener stringers and adjacently engaged on the center line of the slide fastener, when a first imaginary line is set that is tangent to the first boundary line at least on the core string provided on the side edge of the fastener tape and extends parallel to the width direction of the slide fastener, and a second imaginary line that is tangent to the second boundary line at least on the core string provided on the side edge of the fastener tape and extends parallel to the width direction of the slide fastener, the upper part of the fastener element is shaped so that the first imaginary line of the rear fastener element and the second imaginary line of the front fastener element extend with a gap between them without intersecting.

Any of the above-described aspects may further include one or more of the following features or any combination thereof. Needless to say, it is also possible to grasp a new aspect by replacing some features of any of the above-described aspects with any of the following features.
[1] When the slide fastener is in a closed state, the second imaginary line of the front fastener element coincides with or extends adjacent to the third boundary line between the front side surface of the rear fastener element and the first intermediate surface.
[2] In each of the front and rear fastener elements, the width of the upper surface of the element upper part of the fastener element determined between the first virtual line and the second virtual line falls within a range determined by a lower limit value obtained by multiplying 0.8 by half the width of the element upper part determined from the lower edge of the front side surface that is in contact with the fastener tape and extends along the width direction of the slide fastener and the lower edge of the rear side surface that is in contact with the fastener tape and extends along the width direction of the slide fastener, and an upper limit value obtained by multiplying 1.2 by half the value.
[3] A third boundary line is defined between the front side surface and the first intermediate surface, and a fourth boundary line is defined between the rear side surface and the second intermediate surface, and the first to fourth boundary lines are oriented approximately parallel to each other at least across the entire width of the core cord provided at the side edge portion of the fastener tape.
[4] The gap is 1/3 or less of the distance between the first imaginary line and the second imaginary line in one of the fastener elements of the front and rear fastener elements, and/or the gap is 1/5 or more of the distance between the first imaginary line and the second imaginary line.
[5] The upper element portion of each fastener element further includes a first intermediate surface extending along the width direction of the slide fastener between the upper surface and the front side surface, and a second intermediate surface extending along the width direction of the slide fastener between the upper surface and the rear side surface, the first intermediate surface being a curved surface extending downward while curving from a first boundary line between the upper surface and the first intermediate surface to a third boundary line between the first intermediate surface and the front side surface, and the second intermediate surface being a curved surface extending downward while curving from a second boundary line between the upper surface and the second intermediate surface to a fourth boundary line between the second intermediate surface and the rear side surface.
[6] The upper portion of each fastener element may have a tapered shape, for example, as the front and rear sides of the element may be tapered to increase in width as they move away from the upper surface.
[7] The front and rear sides each form an angle within the range of 75° to 85° with respect to the upper surface of the fastener tape.
[8] When the slide fastener is in a closed state, the rear side of the front fastener element of the front and rear fastener elements and the front side of the rear fastener element of the front and rear fastener elements are moved parallel to a common plane along the width direction of the slide fastener, and the rear side of the front fastener element and the front side of the rear fastener element form at least a part of the equal sides of an isosceles triangle with an acute apex angle.
[9] The upper element portion of each fastener element has an upper base end surface located on the tape surface of the fastener tape and an upper tip surface located outside the tape surface of the fastener tape, and when the slide fastener is in a closed state, the upper tip surfaces of the individual fastener elements included in one of the pair of left and right fastener stringers and the upper tip surfaces of the individual fastener elements included in the other of the pair of left and right fastener stringers are alternately arranged on both sides of the center line of the slide fastener.
[10] The element upper part of each fastener element has an upper base end surface located on the tape surface of the fastener tape and an upper tip surface located outside the tape surface of the fastener tape, and when the upper tip surface of the front fastener element of the front and rear fastener elements and the upper tip surface of the rear fastener element of the front and rear fastener elements are moved parallel to a common plane along the center line of the slide fastener in the closed state of the slide fastener, the upper tip surface of the front fastener element and the upper tip surface of the rear fastener element form at least a part of the equal sides of an isosceles triangle with an acute apex angle.
[11] Each fastener element has an element center line parallel to the width direction of the slide fastener, and the element upper and element lower portions of each fastener element are provided on the element center line and are shaped symmetrically with respect to the element center line.
[12] The upper surface of the element upper portion of each fastener element has an elongated rectangular contour along the element center line parallel to the width direction of the slide fastener.
[13] The upper part of the element is a roughly rectangular parallelepiped portion that is elongated between the upper base end face and the upper tip face along the element center line that is parallel to the width direction of the slide fastener, and the lower part of the element is elongated between the lower base end face and the lower tip face along the element center line.
[14] The upper part of the element further includes a first intermediate surface extending along the width direction of the slide fastener between the upper surface and the front side surface, and a second intermediate surface extending along the width direction of the slide fastener between the upper surface and the rear side surface, and in each fastener stringer of the pair of left and right fastener stringers, the upper tip surface of the upper part of the element of the fastener element is offset closer to the side edge of the fastener tape than the lower tip surface, and an intermediate surface is formed between the lower tip surface and the upper tip surface.
[15] The angle between the upper tip surface and the intermediate surface is equal to an angle in the range between 90° and 100°.
[16] At least one of the following conditions (i) and (ii) is satisfied: (i) the width of the intermediate surface gradually increases and then gradually decreases with increasing distance from the upper tip surface along the element centerline; and (ii) the intermediate surface has a circular contour with an arc cut off by the upper tip surface.
[17] The lower element portion includes a base portion having a lower proximal end surface, a head portion having a lower distal end surface, and a neck portion having a narrowed shape to have a minimum element width between the base portion and the head portion.
[18] In each fastener stringer of a pair of left and right fastener stringers, the upper tip surface is positioned outward of the fastener tape along the element center line from the position of the smallest element width at the neck portion; and/or in each fastener element of each fastener stringer of a pair of left and right fastener stringers, the upper tip surface is positioned closer to the position of the smallest element width at the neck portion in the direction along the element center line than the lower tip surface or its most distal end position.
[19] The upper part of each fastener element has an upper base end surface located on the tape surface of the fastener tape and an upper tip end surface located on the opposite side of the upper base end surface, and the upper surface of the upper part of the element is composed of a total of three regions: a main region, a first inclined region that gradually inclines at a first predetermined angle between the main region and the upper end of the upper base end surface, and a second inclined region that gradually inclines at a second predetermined angle between the main region and the upper end of the upper tip end surface.

According to one aspect of the present disclosure, it is possible to further promote narrowing of the fastener element, thereby further reducing the sliding resistance of the slider.

1 is a schematic top view of a slide fastener according to one embodiment of the present disclosure. 1 is a schematic partial perspective view of a slide fastener, with the slider not shown. 1 is a schematic top view of a slide fastener, showing the state in which left and right fastener elements are engaged with each other; FIG. 2 is a left side view of the slide fastener when the slide fastener is in a closed state, with the positions of a first imaginary line DL1 and a second imaginary line DL2 indicated by arrows. 4 is a schematic partial cross-sectional view of the slide fastener taken along the dashed line IV-IV in FIG. 3. FIG. 2 is a schematic perspective view of a fastener element attached to a side edge of a fastener tape. 1 is a schematic top view of two adjacent fastener elements attached to the side edge of a fastener tape. FIG. 1 is a schematic bottom view of two adjacent fastener elements attached to the side edge of a fastener tape. FIG. 1 is a schematic side view of two adjacent fastener elements attached to the side edges of a fastener tape, showing the upper tip surface of the upper element and the lower tip surface of the lower element above and below the mid-plane. This is a schematic side view of two adjacent fastener elements attached to the side edge of a fastener tape (however, the right element is a cross-sectional view), showing the upper base end surface of the upper element and the lower base end surface of the lower element above and below the fastener tape.

Various embodiments and features will be described below with reference to the drawings. Those skilled in the art will be able to combine the various embodiments and/or features without the need for excessive explanation, and will also be able to understand the synergistic effects of such combinations. Duplicate explanations between embodiments will generally be omitted. The reference drawings are primarily intended to describe the invention and have been simplified for ease of illustration. Each feature is not only valid for the slide fastener illustrated in this application, but is understood to be a universal feature that is also applicable to various other slide fasteners not illustrated in this specification.

In this specification, the terms used to indicate directions based on the slide fastener include the front-to-rear direction, left-to-right direction, and up-to-down direction, which are perpendicular to one another. The terms used to indicate directions based on the fastener tape include the tape width direction, tape length direction, and tape thickness direction, which are perpendicular to one another. The terms used to indicate directions based on the fastener element include the element center line, element width direction, and element thickness direction, which are perpendicular to one another. Although not necessarily limited to this, the front-to-rear direction, tape length direction, and element width direction refer to the same direction or are parallel to one another. Similarly, the left-to-right direction, tape width direction, and element center line refer to the same direction or are parallel to one another. Similarly, the up-to-down direction, tape thickness direction, and element thickness direction refer to the same direction or are parallel to one another.

The front-to-back direction corresponds to the direction of movement of the slider 9 for opening and closing the slide fastener 1, and coincides with the longitudinal direction of the slide fastener 1. The left-to-right direction is a direction perpendicular to the front-to-back direction and corresponds to the width direction of the slide fastener 1. The up-to-down direction is a direction perpendicular to the front-to-back and left-to-right directions. Of course, the up-to-down direction does not have to coincide with the vertical direction (direction of gravity). In other words, the terms indicating directions referred to in this specification are unrelated to the vertical direction (direction of gravity).

The slide fastener 1 will be described with reference to Figures 1 to 10. Figure 1 is a schematic top view of the slide fastener 1. Figure 2 is a schematic partial perspective view of the slide fastener 1, with the slider 9 omitted. Figure 3 is a schematic top view of the slide fastener 1, showing the engagement state of the left and right fastener elements 4, 4'. Figure 4 is a left side view of the slide fastener 1 when the slide fastener 1 is in the closed state. At this time, the upper end surfaces 65 of the individual fastener elements 4 included in one of the pair of left and right fastener stringers 2, 2' and the upper end surfaces 65' of the individual fastener elements 4' included in the other of the pair of left and right fastener stringers 2, 2' are alternately arranged on both sides of the center line CL of the slide fastener 1. Figure 5 is a schematic partial cross-sectional view of the slide fastener 1 taken along the dashed line IV-IV in Figure 3. Figure 6 is a schematic perspective view of the fastener elements 4 attached to the side edge portions 31 of the fastener tapes 3, 3'. Fig. 7 is a schematic top view of two adjacent fastener elements 4 attached to the side edge portions 31 of the fastener tapes 3, 3'. Fig. 8 is a schematic bottom view of two adjacent fastener elements 4 attached to the side edge portions 31 of the fastener tapes 3, 3'. Fig. 9 is a schematic side view of two adjacent fastener elements 4 attached to the side edge portions 31 of the fastener tapes 3, 3', showing the upper tip surface 65 of the element upper portion 6 and the lower tip surface 55 of the element lower portion 5 above and below the intermediate surfaces 7, 7' described below. Fig. 10 is a schematic side view of two adjacent fastener elements 4 attached to the side edge portions 31 of the fastener tapes 3, 3' (however, the right element is a cross-sectional view), showing the upper base end surface 64 of the element upper portion 6 and the lower base end surfaces 54, 54' of the element lower portion 5 above and below the fastener tapes 3, 3'.

The slide fastener 1 is typically a flexible, elongated member that extends longitudinally with a substantially constant width. The slide fastener 1 includes a pair of left and right fastener stringers 2, 2' and a slider 9. The slider 9 advances along the center line CL of the slide fastener 1 to alternately engage the individual fastener elements 4 included in one of the pair of left and right fastener stringers 2, 2' with the individual fastener elements 4' included in the other of the pair of left and right fastener stringers 2, 2', and moves backward along the center line CL of the slide fastener 1 to disengage them. A slider of a conventional structure can be used as the slider 9. The slider 9 includes upper blades on the upper element 6, 6' sides of the fastener elements 4, 4' (described below), lower blades on the lower element 5, 5' sides, and connecting posts connecting the upper and lower blades. The connecting posts disengage the engaged left and right fastener elements 4, 4'. The connecting posts of the slider 9 are provided to guide the movement of the lower element parts 5, 5' in both the engagement and disengagement processes of the fastener elements 4, 4'. In both the engagement and disengagement processes of the fastener elements 4, 4', it is optional whether the upper element parts 6, 6' contact the connecting posts of the slider 9 or not, and there may be a gap between them.

The left and right fastener stringers 2, 2' have the same configuration (or are mirror images except for that point) except for the fact that the fastener elements 4, 4' are arranged offset by half a pitch (Pi/2) in the front-to-rear direction to allow for engagement between them. Therefore, the description of the left fastener stringer 2 also applies to the right fastener stringer 2'. Elements of the right fastener stringer 2' that correspond to elements of the left fastener stringer 2 are referenced using the same Arabic numerals as those assigned to the elements of the left fastener stringer 2, followed by a colon.

The fastener stringer 2, 2' includes a fastener tape 3, 3' and a plurality of fastener elements 4, 4' attached to the side edge portions 31, 31' (typically, core strings 33, 33' provided thereon) of the fastener tape 3, 3' at a predetermined pitch Pi. The fastener tape 3, 3' has a tape length LN3 greater than the tape width W3. The fastener elements 4, 4' are individually attached to the side edge portions 31, 31' of the fastener tape 3, 3' at a predetermined pitch Pi along the tape length direction of the fastener tape 3, 3'. The fastener tape 3, 3' is a woven fabric, a knitted fabric, or a mixture of these, and has high flexibility. The fastener elements 4, 4' are resin elements attached to the side edge portions 31, 31' of the fastener tape 3, 3' by injection molding. Examples of materials for the fastener elements 4, 4' include nylon, polyacetal, polyamide, polypropylene, polybutylene terephthalate, polycarbonate, etc., but other materials can also be used.

The fastener tape 3, 3' has an upper tape surface 36, 36' and a lower tape surface 37, 37' as tape surfaces, and has a substantially uniform tape thickness defined by these. The upper tape surface 36, 36' and the lower tape surface 37, 37' of the fastener tape 3, 3' are non-flat surfaces with irregularities corresponding to the tape weave or knit structure, but can be considered to be two-dimensional planes. Furthermore, the fastener tape 3, 3' can be divided into side edge portions 31, 31' to which the fastener elements 4, 4' are attached, and the remaining tape main portion 32, 32'. A core cord 33, 33' can be provided in the side edge portion 31, 31'. The core cord 33, 33' extends longitudinally along the side edge portion 31, 31'. The core cords 33, 33' include upper core cord portions that protrude upward from the upper tape surfaces 36, 36' of the fastener tapes 3, 3' and lower core cord portions that protrude downward from the lower tape surfaces 37, 37' of the fastener tapes 3, 3'. It is also possible to omit either the upper core cord portion or the lower core cord portion.

The fastener elements 4, 4' include lower element portions 5, 5' and upper element portions 6, 6'. The lower element portions 5, 5' and upper element portions 6, 6' are respectively located below and above the plane on which the fastener tapes 3, 3' are located. The upper element portions 6, 6' may be approximately rectangular parallelepiped portions. The lower element portions 5, 5' may have at least one engaging portion 58 and at least one engaged portion 59. The side edge portions 31, 31' and/or core cords 33, 33' of the fastener tapes 3, 3' are sandwiched between the lower element portions 5, 5' and upper element portions 6, 6' in the element thickness direction. The lower element portions 5, 5' include portions that contact and adhere to the tape lower surfaces 37, 37' of the fastener tapes 3, 3'. The upper element portions 6, 6' include portions that contact and adhere to the tape upper surfaces 36, 36' of the fastener tapes 3, 3'. Outside the tape surfaces of the fastener tapes 3, 3', the element lower parts 5, 5' and element upper parts 6, 6' are directly bonded and laminated.

The fastener elements 4, 4' have an element center line CX that is parallel to the tape width of the fastener tapes 3, 3'. The element center line CX is parallel to the width direction of the slide fastener 1 and is positioned at the width center of the fastener elements 4, 4'. On the element center line CX, the upper element portions 6, 6' are shorter than the lower element portions 5, 5'. For example, the length L6 of the upper element portions 6, 6' is greater than two-thirds of the length L5 of the lower element portions 5, 5' and less than four-fifths of the length L5 of the lower element portions 5, 5'.

The upper element portions 6, 6' may be approximately rectangular parallelepiped portions elongated along the element center line CX between the upper base end faces 64, 64' and the upper tip faces 65, 65' (the element width is smaller than the element length). The lower element portions 5, 5' may be elongated along the element center line CX between the lower base end faces 54, 54' and the lower tip faces 55, 55'. This allows the fastener elements 4, 4' to have an elongated overall shape, resembling the appearance of a metal element. The upper base end faces 64, 64' are located on the tape upper surfaces 36, 36' of the fastener tapes 3, 3'. The upper tip faces 65, 65' are located outside the tape surface of the fastener tapes 3, 3'. The lower base end faces 54, 54' are located on the tape lower surfaces 37, 37' of the fastener tapes 3, 3'. The lower tip surfaces 55, 55' are located outside the tape surfaces of the fastener tapes 3, 3'.

Each element upper portion 6, 6' includes a single elongated portion (in the exemplary embodiment, it consists of this single elongated portion) that includes an upper surface 61, 61' extending along the width direction of the slide fastener 1 (e.g., the element center line CX), which is perpendicular to the center line CL of the slide fastener 1, a front side surface 62, 62' extending along the width direction of the slide fastener 1 (e.g., the element center line CX), and a rear side surface 63, 63' extending along the width direction of the slide fastener 1 (e.g., the element center line CX). The element upper portion 6, 6' is located on the element center line CX and extends along the element center line CX, and this also applies to the single elongated portion. Optionally, each element upper portion 6, 6' further includes a first intermediate surface 66, 66' extending along the width direction of the slide fastener 1 (e.g., along the element center line CX) between the upper surface 61, 61' and the front side surface 62, 62', and a second intermediate surface 67, 67' extending along the width direction of the slide fastener 1 (e.g., along the element center line CX) between the upper surface 61, 61' and the rear side surface 63, 63'. By providing the first and second intermediate surfaces 66, 66', 67, 67', the fastener elements 4, 4' can be made to appear thinner when viewed from above (e.g., see Figures 1 and 3). Note that the single elongated portion may be the above-mentioned approximately rectangular parallelepiped portion.

A first boundary line L1 is defined between the upper surface 61, 61' and the first intermediate surface 66, 66', a second boundary line L2 is defined between the upper surface 61, 61' and the second intermediate surface 67, 67', a third boundary line L3 is defined between the front side surface 62, 62' and the first intermediate surface 66, 66', and a fourth boundary line L4 is defined between the rear side surface 63, 63' and the second intermediate surface 67, 67' (see FIG. 3). The first intermediate surface 66, 66' may be a curved surface extending downward (e.g., with a constant or varying curvature and/or an arc) from the first boundary line L1 between the upper surface 61, 61' and the first intermediate surface 66, 66' to the third boundary line L3 between the first intermediate surface 66, 66' and the front side surface 62, 62', but is not limited to this and may also be a flat, inclined surface. The second intermediate surface 67, 67' is a curved surface that extends downward while curving (e.g., with a constant or varying curvature and/or in an arc) from the second boundary line L2 between the upper surface 61, 61' and the second intermediate surface 67, 67' to the fourth boundary line L4 between the second intermediate surface 67, 67' and the rear side surface 63, 63', but is not limited to this and may also be a flat inclined surface.

In an exemplary embodiment, as viewed in the width direction of the slide fastener 1 (see, for example, FIG. 4), the first and second intermediate surfaces 66, 66', 67, 67' are curved surfaces with a constant curvature and are easily distinguishable from the top surfaces 61, 61', which are viewed as substantially flat. The top surfaces 61, 61' are not completely flat, and may curve slightly as they move away from the element center line CX. However, the curvature is extremely small compared to the curvature of the first intermediate surface 66 (e.g., less than 1/10 of that curvature). In this manner, a first boundary line L1 can be defined between the first intermediate surface 66 and the top surfaces 61, 61'. The same applies to the second boundary line L2 between the top surfaces 61, 61' and the second intermediate surfaces 67, 67'. In an exemplary embodiment, the front side surface 62 and the rear side surface 63 are inclined surfaces with a constant slope, i.e., non-curved surfaces, as shown in FIG. 4. Therefore, the boundary between the first intermediate surface 66 and the anterior side surface 62 can be set at the curvature start point of the first intermediate surface 66. Similarly, the boundary between the second intermediate surface 67 and the posterior side surface 63 can be set at the curvature start point of the second intermediate surface 67.

In some cases, the first to fourth boundary lines L1, L2, L3, and L4 are oriented approximately parallel to one another at least across the entire width of the core cord 33 provided on the side edge portions 31 and 31' of the fastener tapes 3 and 3' (or across the main region 61a of the upper surface 61 of the element upper portion 6, which will be described later). This may be a result of the upper surfaces 61 and 61', the front side surfaces 62 and 62', the rear side surfaces 63 and 63', and the first and second intermediate surfaces 66, 66', 67, 67' extending parallel to one another in the same direction.

The distance between the first boundary line L1 and the second boundary line L2 may increase slightly as they approach the upper base end surface 64. The distance between the third boundary line L3 and the fourth boundary line L4 may increase slightly as they approach the upper base end surface 64, 64'. The distance between the first boundary line L1 and the second boundary line L2 may increase slightly as they approach the upper distal end surface 65, 65'. The distance between the third boundary line L3 and the fourth boundary line L4 may increase slightly as they approach the upper distal end surface 65, 65'. That is, the first boundary line L1 and/or the third boundary line L3 may each include a slanted line that slopes forward as they approach the upper base end surface 64, 64' or the upper distal end surface 65, 65'. Similarly, the second boundary line L2 and/or the fourth boundary line L4 may each include a slanted line that slopes rearward as they approach the upper base end surface 64, 64' or the upper distal end surface 65, 65'.

The element upper part 6 has an elongated rectangular outline along the element center line CX (when viewed from above). The upper surface 61 of the element upper part 6 also has an elongated rectangular outline along the element center line CX (when viewed from above). Due to the elongated shape of the element upper part 6 and upper surface 61, the fastener element 4 appears to be a metal element, even though it is actually a resin element.

In this embodiment, when the slide fastener 1 is in a closed state in which an individual fastener element 4 included in one of the pair of left and right fastener stringers 2, 2' is engaged with an individual fastener element 4' included in the other of the pair of left and right fastener stringers 2, 2', the element upper portions 6, 6' of the fastener elements 4, 4' are shaped so as not to straddle (in other words, not to intersect) the center line CL of the slide fastener 1. In other words, the element upper portions 6, 6' of the fastener elements 4, 4' are shaped so that none of the upper surfaces 61, 61', front side surfaces 62, 62', rear side surfaces 63, 63', and upper tip surfaces 65, 65' straddle (in other words, not to intersect) the center line CL of the slide fastener 1. This can further promote narrowing of the fastener elements and further reduce the sliding resistance of the slider. More specifically, rather than faithfully resembling the shape of a metal element, the appearance of the fastener elements 4, 4' can be resembling a metal element using a metal element as a motif, although the shape is different from that of the metal element. As a result, it is possible to promote the narrowing of the individual fastener elements 4, 4', and at the same time, it is promoted to promote the narrowing of the pitch of the fastener elements 4, 4', thereby reducing the sliding resistance of the slider 9 (i.e., it is possible to move the slider 9 with less force to open and close the slide fastener 1). In some cases, it is possible to increase the mechanical strength of the fastener elements 4, 4' and/or promote the simplification of the mold for injection molding the fastener elements 4, 4'.

Just to be clear, narrowing the fastener elements 4, 4' reduces the pitch Pi of the fastener elements 4, 4', which can also reduce the sliding resistance of the slider 9 used to open and close the slide fastener 1. In other words, it is easier to open and close the slide fastener 1 by moving the slider 9 with less force.

As shown in Figure 1, when the fastener elements 4, 4' are engaged, the upper parts 6, 6' of these elements are arranged in a zigzag pattern on both sides of the center line CL of the slide fastener 1. Similarly, when the fastener elements 4, 4' are engaged, the upper surface 61 of the upper part 6 of the left fastener element 4 and the upper surface 61 of the upper part 6' of the right fastener element 4' are arranged in a zigzag pattern on both sides of the center line CL of the slide fastener 1. The upper parts 6, 6' of the elements have portions that face each other in the width direction of the slide fastener 1, so that even if the slide fastener 1 is twisted, interference between the upper parts 6, 6' prevents the fastener elements 4, 4' from becoming disengaged.

Referring to Figure 3, when the slide fastener 1 is in a closed state, in each of the front and rear fastener elements E1, E2 provided on different fastener stringers 2, 2' of a pair of left and right fastener stringers 2, 2' and adjacently engaged on the center line CL of the slide fastener 1, when a first imaginary line DL1 is set that is tangent to the first boundary line L1 at least on the core strings 33, 33' provided on the side edges 31, 31' of the fastener tapes 3, 3' and extends parallel to the width direction of the slide fastener 1, and a second imaginary line DL2 is set that is tangent to the second boundary line L2 at least on the core strings 33, 33' provided on the side edges 31, 31' of the fastener tapes 3, 3' and extends parallel to the width direction of the slide fastener 1, the element upper parts 6, 6' of the fastener elements 4, 4' are shaped so 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 without intersecting with a gap SP between them. This allows the upper surfaces 61, 61' of the element upper parts 6, 6' to be sufficiently narrow. The first imaginary line DL1 is located at a position where a line parallel to the width direction of the slide fastener 1 touches the first boundary line L1 (is inscribed with respect to the fastener elements 4, 4') when moved forward in parallel from the element center 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 touches the second boundary line L2 (is inscribed with respect to the fastener elements 4, 4') when moved backward in parallel from the element center line CX. The third and fourth imaginary lines can also be set similarly for the third and fourth boundary lines L3, L4.

Additionally or alternatively, when the slide fastener 1 is in the closed state, the second imaginary line DL2 of the front fastener element E1 coincides with or extends close to the third boundary line L3, L3' between the front side surface 62, 62' and the first intermediate surface 66, 66' of the rear fastener element E2. This ensures an appropriate width for the upper surfaces 61, 61' of the left and right element upper parts 6, 6'. Additionally or alternatively, in each of the front and rear fastener elements E1 and E2, the width W61 of the upper surface 61 of the element upper portion 6 of the fastener element 4, 4′, determined between the first imaginary line DL1 and the second imaginary line DL2, falls within a range determined by a lower limit of 0.8 multiplied by half the width W6 of the element upper portion 6, 6′, determined by the lower edge of the front side surface 62, 62′ that contacts the fastener tape 3, 3′ and extends along the width direction of the slide fastener 1, and the lower edge of the rear side surface 63, 63′ that contacts the fastener tape 3, 3′ and extends along the width direction of the slide fastener 1, and an upper limit of 1.2 multiplied by half the width W6. Note that if the widths of the upper surfaces 61, 61′ of the left and right element upper portions 6, 6′ are made extremely small, the appearance of the fastener elements 4, 4′ will become different from and will no longer resemble metal elements. As an example, the width W6 of the element upper portion 6 is 1.3 mm or more. The length L6 of the upper element portion 6 is 2.9 mm or more.

The width of the upper surface 61 of the element upper portion 6 of the left fastener element 4 can be understood as being defined by the first imaginary line DL1 and the second imaginary line DL2, but can also be understood as being defined between the first boundary line L1 and the second boundary line L2. Note that due to the inclination of the front side surface 62 and the rear side surface 63 of each element upper portion 6, the width of the upper surface 61 of the element upper portion 6 is smaller than the width of the element upper portion 6 in the same direction.

The above-mentioned gap SP may be 1/3 or less of the distance between the first imaginary line DL1 and the second imaginary line DL2 in one of the front and rear fastener elements E1, E2, and/or may be 1/5 or more of the distance between the first imaginary line DL1 and the second imaginary line DL2. By appropriately adjusting the size of the gap SP, the upper surfaces 61, 61' can be made to an appropriate width.

As shown in Figure 2, for each fastener element 4, the width W6 and height H6 of the element upper portion 6 can satisfy the condition 0.8 < (H6/W6) < 0.95. While narrowing the element upper portion 6 may reduce the attachment strength of the fastener element 4 to the fastener tapes 3, 3', this reduction in attachment strength can be compensated for by increasing the height H6 relative to the width W6. The height H6 is equal to the distance from the tape upper surfaces 36, 36' of the fastener tapes 3, 3' or a plane containing them to the upper surface 61 of the element upper portion 6 (e.g., the main region 61a described below). The fastener element disclosed in Patent Document 1 is designed to satisfy the condition (H6/W6) < 0.8 in order to minimize its protrusion.

The above-mentioned front side surfaces 62, 62' and rear side surfaces 63, 63' are preferably inclined surfaces rather than perpendicular to the tape upper surfaces 36, 36' of the fastener tapes 3, 3'. Specifically, the front side surfaces 62, 62' are downwardly inclined surfaces that approach the tape upper surfaces 36, 36' of the fastener tapes 3, 3' as they extend forward from the upper surfaces 61, 61'. Similarly, the rear side surfaces 63, 63' are downwardly inclined surfaces that approach the tape upper surfaces 36, 36' of the fastener tapes 3, 3' as they extend rearward from the upper surfaces 61, 61'. In order to facilitate narrowing of the fastener elements 4, 4', it is desirable that the front side surfaces 62, 62' and rear side surfaces 63, 63' each form an angle within the range of 75° to 85° with respect to the tape upper surfaces 36, 36' of the fastener tapes 3, 3'. Furthermore, due to the inclination of the front side surfaces 62, 62' and the rear side surfaces 63, 63', the width of each element upper portion 6, 6' of each fastener element 4, 4' increases with increasing distance from the upper surface 61, 61'. For example, as a result, each element upper portion 6, 6' has a tapered shape.

As shown in Figure 4, in some cases, when the rear side surface 63 of the front fastener element 4 and the front side surface 62' of the rear fastener element 4 are translated parallel to a common plane along the width direction of the slide fastener 1 while the slide fastener 1 is in a closed state, the rear side surface 63 of the front fastener element 4 and the front side surface 62' of the rear fastener element 4' form at least a portion of the equal sides of an isosceles triangle RC with an acute apex angle. In other words, a diagonal line including the rear side surface 63 of the front fastener element 4 translated parallel to a common plane and a diagonal line including the front side surface 62' of the rear fastener element 4' form equal sides of an isosceles triangle RC with an acute apex angle. In this way, the symmetry of the left and right fastener elements 4, 4' (with respect to the center line CL of the slide fastener 1) is enhanced.

5, when the upper tip surface 65 of the front fastener element 4 of the front and rear fastener elements E1, E2 and the upper tip surface 65' of the rear fastener element 4' of the front and rear fastener elements E1, E2 are translated parallel to a common plane along the center line CL of the slide fastener 1, the upper tip surface 65 of the front fastener element 4 and the upper tip surface 65' of the rear fastener element 4' form at least a portion of the equal sides of an isosceles triangle with an acute apex angle. In other words, the oblique line including the upper tip surface 65 of the front fastener element 4 translated parallel to a common plane and the oblique line including the upper tip surface 65' of the rear fastener element 4' form the equal sides of an isosceles triangle RC1 with an acute apex angle. In this way, the symmetry of the left and right fastener elements 4, 4' (with respect to the center line CL of the slide fastener 1) is enhanced. The isosceles triangle RC shown in Figure 4 and the isosceles triangle RC1 shown in Figure 5 have an apex angle pointing upward, while the isosceles triangle RC1 has an apex angle pointing downward. The apex angle of the isosceles triangle RC is preferably in the range of 10° to 40°, and more preferably in the range of 15° to 30°. The apex angle of the isosceles triangle RC1 is preferably in the range of 5° to 20°, and more preferably in the range of 7° to 13°.

The shape of the fastener elements 4, 4' will be described in detail below, without any intention of limitation. The element upper parts 6, 6' are block-shaped portions located above the fastener tapes 3, 3', and have upper surfaces 61, 61', front side surfaces 62, 62', rear side surfaces 63, 63', upper base end surfaces 64, 64', and upper tip surfaces 65, 65'. The element upper parts 6, 6' are typically configured so as not to engage with the element upper parts 6, 6' of the fastener elements 4, 4' that engage with the fastener elements 4, 4' that include the element upper parts 6, 6' (i.e., they do not include an engaging structure (e.g., pairs of one or more engaging portions and one or more engaged portions)). The engaging function of the fastener elements 4, 4' can be ensured solely by the element lower parts 5, 5'.

The front side surfaces 62, 62', rear side surfaces 63, 63', upper base end surfaces 64, 64', and upper tip end surfaces 65, 65' are each one of the side surfaces of the element upper portion 6, 6'. The front side surfaces 62, 62' and rear side surfaces 63, 63' extend parallel to and perpendicular to the side edge portions 31, 31' of the fastener tapes 3, 3'. More specifically, the front side surfaces 62, 62' and rear side surfaces 63, 63' extend along the element center line CX between the upper base end surfaces 64, 64' and the upper tip end surfaces 65, 65'. The upper base end surfaces 64, 64' are on the tape surface of the fastener tapes 3, 3', and more specifically, rise upward from the tape upper surfaces 36, 36' of the fastener tapes 3, 3'. The upper tip surfaces 65, 65' are located outside the tape plane of the fastener tapes 3, 3', and more specifically, they rise upward from the intermediate surfaces 7, 7' described below. The upper tip surfaces 65, 65' are located outside the tape plane of the fastener tapes 3, 3' when viewed from the upper base end surfaces 64, 64', and more specifically, they are located away from the upper base end surfaces 64, 64' beyond the side edge portions 31 of the fastener tapes 3, 3' and outside the tape plane of the fastener tapes 3, 3'. Preferably, corners of the joining points on each side surface are chamfered to be rounded. The "outside the tape" refers to the direction from a position on the tape plane of the fastener tape to a position outside the tape plane with respect to a certain fastener stringer, and typically is perpendicular to the side edge portions (or core strings) of the fastener tape.

As described above, the upper surfaces 61, 61' may have an elongated rectangular contour along the element center line CX. Additionally or alternatively, when the width of the upper surfaces 61, 61' is W61 and the length of the upper surfaces 61, 61' is L61 (see FIG. 7), the relationship 1.7 < L61/W61 < 2.3 may be satisfied. The first intermediate surfaces 66, 66' and the second intermediate surfaces 67, 67' (or, if omitted, the front side surfaces 62, 62' and the rear side surfaces 63, 63') are individually connected to the two long sides of the rectangular contour of the upper surfaces 61, 61'. The upper base end surfaces 64, 64' and the upper tip end surfaces 65, 65' are individually connected to the two short sides of the rectangular contour of the upper surfaces 61, 61'. Preferably, the corners at the connection points between the upper surfaces 61, 61' and the above-mentioned surfaces are chamfered and rounded. Due to the inclination of the front side surface 62, rear side surfaces 63, 63', upper base end surface 64 and upper tip surface 65, the upper surface 61 can have an area that is smaller than the top view shape (contour) of the element upper part 6.

To make the top surfaces 61, 61' appear narrower, the front side surfaces 62, 62' and rear side surfaces 63, 63' may be sloped. That is, the front side surfaces 62, 62' slope away from the element center line CX as they extend downward from the top surfaces 61, 61' (or the first intermediate surfaces 66, 66'), while the rear side surfaces 63, 63' slope away from the element center line CX as they extend downward from the top surfaces 61, 61' (or the second intermediate surfaces 67, 67') (see Figures 9 and 10). As a result, the element top portions 6, 6' are shaped like a trapezoid when viewed in a direction along the element center line CX. Here, the top surfaces 61, 61' coincide with the upper base of the trapezoid.

The upper base end surfaces 64, 64' are inclined away from the upper tip surfaces 65, 65' as they extend downward from the upper surfaces 61, 61', and the upper tip surfaces 65, 65' can be inclined away from the upper base end surfaces 64, 64' as they extend downward from the upper surfaces 61, 61' (see FIG. 5). When the plane on which the tape upper surfaces 36, 36' of the fastener tapes 3, 3' exist is taken as a reference, the angle θ ₆₄ (see FIG. 5) formed between this plane and the upper base end surface 64 is preferably larger than the angle θ ₆₂ (see FIG. 10) formed between this plane and the front side surface 62 and larger than the angle θ ₆₃ (see FIG. 10) formed between this plane and the rear side surface 63, 63'. The same applies to the angle θ ₆₅ formed between this plane and the upper tip surface 65. The relatively gentle inclination of the formed angle θ ₆₂ and the formed angle θ ₆₃ satisfies both the appearance of the elongated shape of the element upper portion 6 and the mounting strength of the fastener element 4 .

The upper surface 61, 61' of the element upper portion 6, 6' may consist of a single two-dimensional surface or multiple two-dimensionally continuous surfaces. In the latter case, the upper surface 61, 61' may consist of a total of three regions: a main region 61a, a first inclined region 61b, and a second inclined region 61c, as shown in FIG. 4 (see FIG. 5). The first inclined region 61b gently inclines at a first predetermined angle θ _61b between the main region 61a and the upper end of the upper base end surface 64. The second inclined region 61c gently inclines at a second predetermined angle θ _61c between the main region 61a and the upper end of the upper tip end surface 65.

The main region 61a may be a flat surface oriented parallel to the tape upper surface 36, 36' of the fastener tape 3, 3' or a plane including the tape upper surface 36, 36'. The first predetermined angle θ _61b may be the angle between the plane on which the main region 61a exists and the first inclined region 61b. The second predetermined angle θ _61c may be the angle between the plane on which the main region 61a exists and the second inclined region 61c. Advantageously, the second predetermined angle θ _61c is smaller than the first predetermined angle θ _61b . This makes it easier to provide the upper tip surface 65 with a sufficient height, and, for example, prevents the element upper portions 6, 6' from interfering with each other and causing the fastener elements 4, 4' to disengage when the slide fastener 1 is twisted.

Further explaining with reference to Figure 5, the upper base end surface 64 extends steeply upward between positions P1 and P2. The upper surface 61 extends between positions P2 and P5. Specifically, the first inclined region 61b slopes gently upward from position P2 to position P3. The main region 61a extends horizontally between positions P3 and P4. The second inclined region 61c slopes gently downward from position P4 to position P5. The upper tip surface 65 extends steeply downward between positions P5 and P6. The distance between positions P1 and P2 and the distance between positions P5 and P6 are both sufficiently smaller than the distance between positions P2 and P5.

As described above, the element lower portions 5, 5' are elongated along the element center line CX between the lower base end surfaces 54, 54' and the lower tip surfaces 55, 55', and are shaped to have at least one engaging portion 58 and at least one engaged portion 59 between the lower base end surfaces 54, 54' and the lower tip surfaces 55, 55'. The element lower portion 5 is typically configured to engage with each of the element lower portions 5', 5' of the two fastener elements 4', 4' that are mating members of the fastener element 4 that includes this element lower portion 5. The engaging portion 58 and the engaged portion 59 are appropriately shaped for this purpose. The engaging portion 58 typically protrudes along the center line CL of the slide fastener 1 or an axis parallel thereto. The engaged portion 59 typically is recessed along the center line CL of the slide fastener 1 or an axis parallel thereto.

The lower base end surfaces 54, 54' rise downward from the tape undersurface 37 of the fastener tapes 3, 3'. The lower tip surfaces 55, 55' are located beyond the side edge portions 31 of the fastener tapes 3, 3' and away from the lower base end surfaces 54, 54' (i.e., outside the tape plane of the fastener tapes 3, 3'). The lower tip surfaces 55, 55' may be the most protruding curved surface on the element central axis CX of the fastener element 4. As shown in FIG. 5, the lower tip surfaces 55, 55' slope steeply downward from position P8 to position P7. The lower tip surfaces 55, 55' may include a gradual curved surface near position P7.

In some cases, the upper tip surface 65 is offset closer to the side edge 31 (or core cord 33) of the fastener tape 3, 3' than the lower tip surface 55, 55', and an intermediate surface 7, 7' is formed between the lower tip surface 55, 55' and the upper tip surface 65. This makes it easier to prioritize narrowing the width of the element upper portion 6, 6'. In this regard, the narrow width of the element upper portion 6, 6' ensures that the appearance of the fastener element 4 resembles a metal element. In this way, it is possible to provide a narrow fastener element 4 that resembles a metal element and is based on the motif of a metal element.

The intermediate surfaces 7, 7' may be flat surfaces perpendicular to the element thickness direction, but may be, but are not necessarily, flush with the fastener tapes 3, 3'. Preferably, the intermediate surfaces 7, 7' are flush with the upper tape surfaces 36, 36' of the fastener tapes 3, 3', or are closer to the upper tape surfaces 36, 36' than the lower tape surfaces 37 of the fastener tapes 3, 3'. In this case, the thickness of the lower element portions 5, 5' below the intermediate surfaces 7, 7' can be sufficiently ensured, thereby increasing the engagement strength between the fastener elements 4, 4'. Typically, the angle θ1 between the upper tip surface 65 and the intermediate surface 7, 7' is equal to an angle between 90° and 100° (see FIG. 5). The angle _θ55 between the lower tip surface 55, 55' and the intermediate surface 7, 7' is equal to an angle between 80° and 90° (see FIG. 5). The intermediate surfaces 7, 7' may also be inclined or non-flat.

The top view shape of the intermediate surfaces 7, 7' (or their exposed shape when the fastener elements 4, 4' are disengaged) may depend on the engagement structure of the lower element portions 5, 5'. Typically, (i) the width of the intermediate surfaces 7, 7' gradually increases and then gradually decreases as they move away from the upper tip surface 65 along the element center line CX; and/or the intermediate surfaces 7, 7' have a circular contour with an arc cut off by the upper tip surface 65.

As can be seen from FIG. 3, the intermediate surface 7 of the fastener element 4 may include two mounting areas 71 on which the upper element portions 6', 6' (e.g., shoulder portions 8, described below) of the two mating fastener elements 4', 4' are individually mounted, and an intermediate area 72 between these two mounting areas 71. The area of the intermediate area 72 may be within a range of 0.5 to 1.5 times the total area of the two mounting areas 71. The same applies to the fastener element 4'. When the fastener elements 4, 4' are engaged, their intermediate areas 72, 72' are visible (when viewed from above). At this time, the intermediate areas 72, 72' are located at the back between the upper element portions 6, 6' (and between their upper surfaces 61, 61') and are not noticeable.

In some cases, including the illustrated example, the lower element portion 5 includes a base portion 51 having a lower base end surface 54, a head portion 53 having a lower tip end surface 55, and a neck portion 52 that is constricted to provide the smallest element width between the base portion 51 and the head portion 53. The head portion 53 includes at least one engaging portion 58, namely, two engaging portions 58 that protrude on opposite sides in the tape length direction (see Figure 6). The neck portion 52 includes at least one engaged portion 59, namely, two engaged portions 59 that are recessed to form a constriction in the neck portion 52. The same applies to the lower element portion 5'.

The base 51 is formed with approximately the same width as the element upper parts 6, 6'. That is, the width W51 of the base 51 is equal to the width W6 of the element upper parts 6, 6'. Therefore, the pitch Pi of the fastener elements 4 can be determined based on the structure of the element lower parts 5, 5'. The length of the base 51 along the element center line CX is shorter than the length L6 of the element upper parts 6, 6'. The lower base end faces 54, 54' are located on the opposite side of the fastener tapes 3, 3' from the upper base end faces 64, 64' of the element upper parts 6, 6'. The base 51 has two side faces 512, 513 arranged perpendicular to the element width direction, both of which extend along the element center line CX and straddle the core cord 33 (see Figure 8).

The neck portion 52 has a width W52, which is the narrowest element width, at the lower element portion 5, 5' (see Figure 8). The head portion 53 has a width W53, which is the widest element width at the lower element portion 5, 5' other than the base portion 51. The width of the lower element portion 5, 5' gradually decreases from the midpoint between the base portion 51 and the neck portion 52 (i.e., the neck start position) as it extends outward from the tape until it reaches width W52. After passing width W52, the width gradually increases until it reaches width W53. As a result, the neck portion 52 is shaped to have a constriction, and each engaged portion 59 is shaped to have a semi-cylindrical receiving space. The width of the head portion 53 gradually decreases from width W53 outward from the tape. The lower surfaces of the base portion 51, neck portion 52, and head portion 53 are formed on the same plane, forming a single lower surface 56 of the lower element portion 5, 5'. The side surfaces of the base portion 51, neck portion 52, and head portion 53 are continuous and form a single contour. As shown in FIG. 5, the base portion 51 is fixed to the core string 33 having a width defined between positions P11 and P12 and to a part of the fastener tapes 3, 3' adjacent thereto.

The two engaging portions 58 may each be separated by the element center line CX of the fastener element 4 and/or may be mirror-symmetrical about the element center line CX (i.e., each is a semi-cylindrical portion). Similarly, the two engaged portions 59 may each be separated by the element center line CX of the fastener element 4 and/or may be mirror-symmetrical about the element center line CX (i.e., each is a portion having a semi-cylindrical receiving space).

The two engaged portions 59 are each at least partially closed from above by two shoulders 8 of the element upper portions 6, 6' (see Figure 6). The shoulders 8 are located on both sides of the neck portion 52 when the fastener element 4 is viewed from below (see Figure 8). When the left and right fastener elements 4, 4' are engaged, the head 53 of one of the fastener elements 4 on the left or right side is inserted and held between the necks 52' of the adjacent fastener element 4' on the other side. At this time, the head 53 is located directly below the shoulders 8' of those fastener elements 4', restricting its upward displacement. In other words, the shoulders of the fastener element 4 function as parts that restrict the displacement of the mating fastener element 4'. Advantageously, the shoulders 8 form part of the block-shaped element upper portions 6, 6' and do not have a shape that is distinguishable as a shoulder (when the element upper portions 6, 6' are viewed from above).

The upper tip surface 65 is positioned outward of the fastener tape 3, 3' relative to the minimum element width W52 at the neck 52 in the direction along the element center line CX (see Figures 5 to 8). This allows the element upper portions 6, 6' to be formed longer and/or allows the shoulder portions 8 to have sufficient area. Additionally or alternatively, the upper tip surface 65 is positioned closer to the minimum element width W52 at the neck 52 relative to the lower tip surfaces 55, 55' or their extreme ends in the direction along the element center line CX. That is, the length L8 shown in Figure 8 is shorter than the length L9. In this case, the length L7 of the intermediate surfaces 7, 7' can be sufficiently secured (see Figure 7). Note that increasing the length L7 of the intermediate surfaces 7, 7' enhances stability when the left and right fastener elements 4, 4' are engaged.

The manufacturing method of the slide fastener 1 is clear to those skilled in the art from the above description, and will not be described further. The cavity shape of the mold used for injection molding the fastener element 4 is simplified thanks to the relatively simple shape of the upper element portions 6, 6'. The slope of the side surfaces (e.g., the front side surface 62 and rear side surface 63) of the upper element portions 6, 6' serves as a draft angle for the fastener element 4 from the mold cavity. It is preferable to set the gate position at a location other than the molding cavity surface of the upper surfaces 61, 61' of the upper element portions 6, 6' (e.g., the lower tip surfaces 55, 55'). This ensures high flatness and/or smoothness of the upper surfaces 61, 61'. The lower tip surfaces 55, 55' may have gate marks. It is preferable that the cavity surface of the mold also have high smoothness so that the outer surface of the fastener element 4 has high smoothness.

Metal foil can be attached to the upper surfaces 61, 61' to increase gloss. In this case, the first inclined region 61b and the second inclined region 61c can ensure light reflection over a wider angle range. Please note that this also applies when no metal foil is provided.

In light of the above teachings, those skilled in the art will be able to make various modifications to the embodiments. The reference numerals included in the claims are for reference purposes only and should not be used to limit the scope of the claims.

DESCRIPTION OF SYMBOLS 1: Slide fastener 2: Fastener stringer 3: Fastener tape 4: Fastener element 5: Lower element 6: Upper element 7: Intermediate surface 8: Shoulder 9: Slider 51: Base 52: Neck 53: Head 54: Lower base end surface 55: Lower tip surface 58: Engaging portion 59: Engaged portion 61: Upper surface 61a: Main region 61b: First inclined region 61c: Second inclined region 62: Front side surface 63: Rear side surface 64: Upper base end surface 65: Upper tip surface 71: Placement region 72: Intermediate region

Claims (22)

A slide fastener (1),
a pair of left and right fastener stringers (2, 2'), each of which includes a fastener tape (3, 3') and a plurality of fastener elements (4, 4') attached to side edge portions (31, 31') of the fastener tape (3, 3') at a predetermined pitch, each of which includes an element lower portion (5, 5') and an element upper portion (6, 6') respectively provided below and above a plane on which the fastener tape (3, 3') exists, and each of which includes an element lower portion (5, 5') having at least one engaging portion (58) and at least one engaged portion (59);
a slider (9) that moves forward on the center line (CL) of the slide fastener (1) to alternately engage the individual fastener elements (4) included in one of the pair of left and right fastener stringers (2, 2') with the individual fastener elements (4') included in the other of the pair of left and right fastener stringers (2, 2'), and moves backward on the center line (CL) of the slide fastener (1) to release the engagement;
The element upper portion (6, 6') of each fastener element (4, 4') is a single elongated portion having an upper surface (61, 61') extending along the width direction of the slide fastener (1) perpendicular to the center line (CL) of the slide fastener (1), a front side surface (62, 62') extending along the width direction of the slide fastener (1), and a rear side surface (63, 63') extending along the width direction of the slide fastener (1), and includes a single elongated portion whose narrow width is defined by the front side surface (62, 62') and the rear side surface (63, 63') ,
In a closed state of the slide fastener (1) in which an individual fastener element (4) included in one of the pair of left and right fastener stringers (2, 2') is engaged with an individual fastener element (4') included in the other of the pair of left and right fastener stringers (2, 2'), the element upper parts (6, 6') of the fastener elements (4, 4') are shaped so as not to straddle a center line (CL) of the slide fastener (1) ,
The element upper portion (6, 6') of each fastener element (4, 4') further includes a first intermediate surface (66, 66') extending along the width direction of the slide fastener (1) between the upper surface (61, 61') and the front side surface (62, 62'), and a second intermediate surface (67, 67') extending along the width direction of the slide fastener (1) between the upper surface (61, 61') and the rear side surface (63, 63'), a first boundary line (L1) is defined between the upper surface (61, 61') and the first intermediate surface (66, 66'), and a second boundary line (L2) is defined between the upper surface (61, 61') and the second intermediate surface (67, 67'),
In the closed state of the slide fastener (1), in each of the front and rear fastener elements (E1, E2) that are provided on different fastener stringers (2, 2') of the pair of left and right fastener stringers (2, 2') and that are adjacently engaged on the center line (CL) of the slide fastener (1), at least a first imaginary line (DL1) that is in contact with the first boundary line (L1) and extends parallel to the width direction of the slide fastener (1) on a core string (33, 33') provided on the side edge portion (31, 31') of the fastener tape (3, 3') and a small imaginary line (DL2) that is in contact with the first boundary line (L1) and extends parallel to the width direction of the slide fastener (1), When a second imaginary line (DL2) is set that is in contact with the second boundary line (L2) and extends parallel to the width direction of the slide fastener (1) at least on a core string (33, 33') provided on the side edge portion (31, 31') of the fastener tape (3, 3'), the element upper portions (6, 6') of each fastener element (4, 4') are shaped so 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 without intersecting with a gap (SP) therebetween,
In each of the front and rear fastener elements (E1, E2), the width (W61) of the upper surface (61, 61') of the element upper portion (6, 6') of the fastener element (4, 4') determined between the first imaginary line (DL1) and the second imaginary line (DL2) falls within a range determined by a lower limit value obtained by multiplying 1/2 of the width (W6) of the element upper portion (6, 6') determined by the lower side of the front side surface (62, 62') that contacts the fastener tape (3, 3') and extends along the width direction of the slide fastener (1) and the lower side of the rear side surface (63, 63') that contacts the fastener tape (3, 3') and extends along the width direction of the slide fastener (1) by 0.8 and an upper limit value obtained by multiplying the half value by 1.2,
The slide fastener of each fastener element (4, 4') satisfies 0.8<(H6/W6)<0.95 with respect to the width (W6) of the element upper portion (6, 6') and the height (H6) of the element upper portion (6, 6'). The slide fastener according to claim 1, wherein, in the closed state of the slide fastener (1), the second imaginary line (DL2) of the front fastener element (E1) coincides with or extends adjacent to a third boundary line (L3) between the front side surface (62, 62') and the first intermediate surface (66, 66') of the rear fastener element ( E2) . 2. The slide fastener according to claim 1, wherein a third boundary line (L3) is defined between the front side surface (62, 62') and the first intermediate surface (66, 66'), a fourth boundary line (L4) is defined between the rear side surface (63) and the second intermediate surface (67, 67'), and the first to fourth boundary lines (L1, L2, L3, L4) are oriented approximately parallel to each other at least across the entire width of the core strings (33, 33') provided on the side edge portions (31, 31') of the fastener tapes ( 3 , 3'). The slide fastener according to claim 1, wherein the gap (SP) is 1/3 or less of the distance between the first imaginary line (DL1) and the second imaginary line (DL2) in one of the front and rear fastener elements ( E1 , E2). The slide fastener according to claim 4 , wherein the gap (SP) is equal to or greater than 1/5 of the distance between the first imaginary line (DL1) and the second imaginary line (DL2). The element upper portion (6, 6') of each fastener element (4, 4') further includes a first intermediate surface (66, 66') extending along the width direction of the slide fastener (1) between the upper surface (61, 61') and the front side surface (62, 62'), and a second intermediate surface (67, 67') extending along the width direction of the slide fastener (1) between the upper surface (61, 61') and the rear side surface (63, 63'),
The first intermediate surface (66, 66') is a curved surface that extends downward while curving from a first boundary line (L1) between the upper surface (61, 61') and the first intermediate surface (66, 66') to a third boundary line (L3) between the first intermediate surface (66, 66') and the front side surface (62, 62'),
6. A slide fastener according to claim 1, wherein the second intermediate surface (67, 67') is a curved surface that extends downward while curving from a second boundary line (L2) between the upper surface (61, 61') and the second intermediate surface (67, 67') to a fourth boundary line (L4) between the second intermediate surface (67, 67 ') and the rear side surface (63, 63'). A slide fastener according to any one of claims 1 to 5, wherein the element upper portion (6, 6') of each fastener element (4, 4') becomes wider as it moves away from the upper surface (61, 61') due to the inclination of the front side surface (62, 62 ') and the rear side surface (63). The slide fastener according to any one of claims 1 to 5, wherein the front side surface (62, 62') and the rear side surface (63) each form a first angle within a range of 75° to 85° with respect to the tape upper surface ( 36 ) of the fastener tape (3, 3'). 6. The slide fastener according to claim 1, wherein when the rear side surface (63) of the front fastener element (E1) of the front and rear fastener elements (E1, E2) and the front side surface (62') of the rear fastener element (E2) of the front and rear fastener elements (E1, E2) are moved parallel to a common plane along the width direction of the slide fastener (1) in the closed state of the slide fastener (1), the rear side surface (63) of the front fastener element (E1) and the front side surface (62') of the rear fastener element ( E2 ) form at least a part of the equal sides of an isosceles triangle with an acute apex angle. The element upper portion (6, 6') of each fastener element (4, 4') has an upper base end surface (64, 64') positioned on the tape surface of the fastener tape (3, 3') and an upper tip end surface (65, 65') positioned outside the tape surface of the fastener tape (3, 3'),
6. A slide fastener according to any one of claims 1 to 5, wherein, in the closed state of the slide fastener (1), the upper tip surfaces (65, 65') of the individual fastener elements (4) included in one of the pair of left and right fastener stringers (2, 2') and the upper tip surfaces (65') of the individual fastener elements (4') included in the other of the pair of left and right fastener stringers (2, 2 ') are alternately arranged on both sides of a center line (CL) of the slide fastener (1). The element upper portion (6, 6') of each fastener element (4, 4') has an upper base end surface (64, 64') positioned on the tape surface of the fastener tape (3, 3') and an upper tip end surface (65, 65') positioned outside the tape surface of the fastener tape (3, 3'),
6. The slide fastener according to claim 1, wherein, in the closed state of the slide fastener (1), when the upper tip surface (65) of the front fastener element (E1) of the front and rear fastener elements (E1, E2) and the upper tip surface (65') of the rear fastener element (E2) of the front and rear fastener elements (E1, E2) are moved parallel to a common plane along a center line (CL) of the slide fastener (1), the upper tip surface (65) of the front fastener element (E1) and the upper tip surface (65') of the rear fastener element (E2) form at least a part of the equal sides of an isosceles triangle with an acute apex angle . A slide fastener according to any one of claims 1 to 5, wherein each fastener element (4, 4') has an element center line (CX) parallel to the width direction of the slide fastener (1), and the element upper part (6, 6') and the element lower part (5, 5') of each fastener element (4, 4 ') are provided on the element center line (CX) and are shaped symmetrically with respect to the element center line (CX). A slide fastener according to any one of claims 1 to 5, wherein the upper surface (61, 61') of the element upper portion (6, 6') of each fastener element (4, 4 ') has an elongated rectangular contour along an element center line (CX) parallel to the width direction of the slide fastener (1). The element upper portion (6, 6') is a substantially rectangular parallelepiped portion that is elongated along an element center line (CX) that is parallel to the width direction of the slide fastener (1) between an upper base end surface (64, 64') and an upper tip end surface (65, 65'),
6. A slide fastener according to claim 1 , wherein the element lower portion (5) is shaped to be elongated along the element center line (CX) between a lower base end surface (54) and a lower tip end surface (55). The element upper portion (6, 6') further includes a first intermediate surface (66, 66') extending along the width direction of the slide fastener (1) between the upper surface (61, 61') and the front side surface (62, 62'), and a second intermediate surface (67, 67') extending along the width direction of the slide fastener (1) between the upper surface (61, 61') and the rear side surface (63, 63'),
15. The slide fastener according to claim 14, wherein in each fastener stringer (2, 2′) of the pair of left and right fastener stringers (2, 2′), the upper tip surface (65, 65′) of the element upper portion (6, 6′) of the fastener element (4, 4′) is offset closer to the side edge portion (31, 31′) of the fastener tape (3, 3′) than the lower tip surface (55), and an intermediate surface (7, 7′) is formed between the lower tip surface (55) and the upper tip surface ( 65 , 65′). 16. A slide fastener according to claim 15 , wherein the angle between said upper tip surface (65, 65') and said intermediate surface (7, 7') is equal to an angle ranging between 90° and 100°. At least one of the following conditions (i) and (ii) is satisfied:
16. A slide fastener according to claim 15, wherein (i) the width of the intermediate surface (7, 7') gradually increases and then gradually decreases as it moves away from the upper tip surface (65, 65') along the element center line (CX); and (ii) the intermediate surface (7, 7') has a contour of a perfect circle with an arc cut off by the upper tip surface ( 65 , 65'). 15. A slide fastener according to claim 14, wherein the element lower part (5) includes a base part (51) having the lower base end surface (54), a head part (53) having the lower tip surface (55), and a neck part (52) having a narrowed shape so as to have a minimum element width between the base part (51) and the head part (53 ),
a slide fastener in which, in each fastener stringer (2, 2') of the pair of left and right fastener stringers (2, 2'), the upper tip surface (65, 65') is positioned outward of the fastener tape (3, 3') from the position of the smallest element width in the neck portion (52) along the element center line (CX); 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 upper tip surface (65, 65') is positioned closer to the position of the smallest element width in the neck portion (52) in the direction along the element center line (CX) as compared to the lower tip surface (55) or its most distal end position. Each element upper portion (6, 6') of each fastener element (4, 4') has an upper base end surface (64, 64') positioned on the tape surface of the fastener tape (3, 3') and an upper tip end surface (65, 65') positioned on the opposite side of the upper base end surface (64, 64'),
6. A slide fastener according to claim 1, wherein the upper surface (61, 61') of the element upper portion (6) is composed of a total of three regions: a main region (61a), a first inclined region (61b) that gradually inclines at a first predetermined angle between the main region (61a) and the upper end of the upper base end surface (64), and a second inclined region (61c) that gradually inclines at a second predetermined angle between the main region (61a) and the upper end of the upper tip surface (65, 65' ). The angle (θ) between the plane on which the main region (61a) exists and the second inclined region (61c) is an acute angle. _61c ) is the angle (θ ) between the plane on which the main region (61a) exists and the acute angle between the first inclined region (61b). _61b 20. The slide fastener according to claim 19, wherein the length is smaller than 1/2. The element lower portion (5, 5') is shaped to be elongated between a lower base end surface (54) and a lower tip end surface (55) along an element center line (CX) parallel to the width direction of the slide fastener (1),
The element lower portion (5, 5') includes a base portion (51) having the lower base end surface (54), a head portion (53) having the lower tip end surface (55), and a neck portion (52) having a narrowed shape so as to have a minimum element width between the base (51) and the head portion (53),
A slide fastener according to any one of claims 1 to 5, wherein the base (51) is an elongated portion having a narrow width defined by a front side extending along the width direction of the slide fastener (1) and a rear side extending along the width direction of the slide fastener (1). the front side surface (62, 62') and the rear side surface (63) of the single elongated portion each form a first angle within a range of 75° to 85° with respect to the tape upper surface (36) of the fastener tape (3, 3');
22. The slide fastener according to claim 21, wherein the front side and the rear side of the base (51) each form a second angle with respect to the tape underside (37, 37') of the fastener tape (3, 3'), the second angle being greater than the first angle.