Patent Description:
Patent literature <NUM> discloses a technology that provides a slide fastener with narrower width. Left and right fastener elements are coupled alternately along a movement direction of a slider. The length of each fastener element is less than a width, in the left-right direction, of the alternately coupled left and right fastener elements. The shape of each fastener element includes a bent or curved shape.

[PLT <NUM>] <CIT> slide fastener according to the preamble of claim <NUM> is known from <CIT>.

In a conventional slide fastener shown in <FIG> of the present application, when a slider is pulled for coupling the left and right fastener elements <NUM>, a head <NUM> of left fastener element <NUM> is required to enter into an interspace between heads <NUM> of right fastener elements arranged adjacently in the right fastener tape. Likewise, a head <NUM> of right fastener element <NUM> is required to enter into an interspace between heads <NUM> of left fastener elements arranged adjacently in the left fastener tape. Force required for this movement of slider causing engagements of fastener elements <NUM> may be hardly small for physically-weak people such as infant or aged people.

The present inventors have newly recognized a value of supplying a slide fastener which allows reduced force for moving a slider for coupling fastener elements.

According to the present invention, the above problems are solved by a slide fastener according to claim <NUM>. Preferred embodiments of the invention are claimed in dependent claims <NUM> to <NUM>.

Hereinafter, non-limiting exemplary embodiments of the present invention will be described with reference to <FIG>. Disclosed one or more exemplary embodiments and respective features included in the exemplary embodiments are not mutually exclusive. A skilled person would be able to combine respective exemplary embodiments and/or respective features without requiring excess descriptions. Also a skilled person would appreciate synergistic effects of such combinations. Overlapping descriptions among the exemplary embodiments would be basically omitted. Referenced drawings are prepared for the purpose of illustration of the invention.

In the present specification, terms of direction defined as follows will be used. Front-rear direction matches a movement direction of a slider or would be recognized based on a movement direction of a slider. Left-right direction is orthogonal to the front-rear direction in a plan where paired fastener stringers exist. Up-down direction is orthogonal to the front-rear direction and the left-right direction respectively.

As shown in <FIG>, a slide fastener <NUM> is provided with a pair of fastener stringers <NUM> and at least one slider <NUM> for opening and closing the pair of fastener stringers <NUM>. Envisioned are examples where the slide fastener <NUM> is provided with two or more sliders. For the sake of description, a fastener tape <NUM> and a fastener element <NUM> of the left fastener stringer <NUM> of the pair may possibly be referred to as a left fastener tape <NUM> and a left fastener element <NUM> respectively. Likewise, a fastener tape <NUM> and a fastener element <NUM> of the right fastener stringer <NUM> of the pair may possibly be referred to as a right fastener tape <NUM> and a right fastener element <NUM> respectively.

The left and right fastener stringers <NUM> are closed by frontward movement of the slider <NUM>, and the left and right fastener stringers <NUM> are opened by rearward movement of the slider <NUM>. Closed left and right fastener stringers <NUM> results in coupled left and right fastener elements <NUM>. Opened left and right fastener stringers <NUM> results in decoupled left and right fastener elements <NUM>.

Each fastener stringer <NUM> included in the paired fastener stringers <NUM> has a fastener tape <NUM> and a plurality of fastener elements <NUM> attached to the fastener tape <NUM>. The fastener tape <NUM> is a thin flexible member and has upper and lower tape surfaces as a pair of tape surfaces. The fastener tape <NUM> has a side-edge <NUM> to which the fastener elements <NUM> are attached. Core thread <NUM> may be provided at the side-edge <NUM> for strengthening the coupling of the fastener tape <NUM> and the fastener element <NUM>. In some cases, the fastener tape <NUM> is a woven fabric or knitted fabric or combination thereof. The core thread <NUM> may be woven together with the fastener tape <NUM> or sewn to the fastener tape <NUM>.

The fastener element <NUM> has a base portion <NUM> secured to the fastener tape <NUM> and a terminal portion <NUM> positioned opposite to the base portion <NUM>. The terminal portion <NUM> is provided outwardly of fastener tape relative to the base portion <NUM>. Outwardly of fastener tape indicates a direction directed from a point over the tape surface of the fastener tape <NUM> to a point external to the tape surface. The terminal portion <NUM> of the fastener element <NUM> provided at one fastener tape <NUM> is arranged closer to the other fastener tape <NUM> than the base portion <NUM> of the fastener element <NUM>. The base portion <NUM> exists on the tape surface of the fastener tape <NUM>, particularly on the side-edge <NUM> and the core thread <NUM> of the fastener tape <NUM>. The terminal portion <NUM> does not exist on the tape surface of the fastener tape <NUM>. The fastener element <NUM> extends in the left-right direction from the base portion <NUM>, secured to the side-edge <NUM> of the fastener tape <NUM>, toward the terminal portion <NUM>, not existing on the tape surface of the fastener tape <NUM>.

The terminal portion <NUM> of the fastener element <NUM> has a terminal surface <NUM> to be opposed to or touched by a coupling pillar <NUM> of the slider <NUM>. In some cases, the terminal surface <NUM> touches the coupling pillar <NUM> of the slider <NUM> and slides on the side surface thereof. The base portion <NUM> of the fastener element <NUM> has a base end surface <NUM> to be opposed to or touched by a flange <NUM> of the slider <NUM>. In some cases, the base end surface <NUM> touches the flange <NUM> of the slider <NUM> and slides on the inner surface thereof. The terminal surface <NUM> of the fastener element <NUM> touches and/or slides on the side surface of the coupling pillar <NUM> so that the posture of the fastener element <NUM> may be stabilized. Likewise, the base end surface <NUM> of the fastener element <NUM> touches and/or slides on the inner surface of the flange <NUM> so that the posture of the fastener element <NUM> may be stabilized. In some cases, the base end surface <NUM> and/or the terminal surface <NUM> includes at least partially a flat surface.

The base portion <NUM> of the fastener element <NUM> has an upper portion provided above the fastener tape <NUM> and a lower portion provided under the fastener tape <NUM>. The base end surface <NUM> of the base portion <NUM> is divided into upper and lower sections by the fastener tape <NUM>. The upper section of the base end surface <NUM> is opposed to, or touches or in some cases slides on the inner surface of the upper flange of the slider <NUM>. The lower section of the base end surface <NUM> is opposed to, or touches or in some cases slides on the inner surface of the lower flange of the slider <NUM>.

Interspace between the terminal surface <NUM> and the base end surface <NUM> in the left-right direction matches the width of the fastener element <NUM> in the left-right direction. The fastener element <NUM> has front and rear surfaces which extend between the base end surface <NUM> and the terminal surface <NUM>. The front surface extends in left-right direction so as to form a first recess <NUM> and an engaging protrusion <NUM> described below. The front surface is a surface that face frontward of the movement direction of the slider. The rear surface extends in left-right direction so as to form an engaged recess <NUM> described below. The rear surface is a surface that face rearward of the movement direction of the slider.

As shown in <FIG>, the fastener element <NUM> has an intermediate portion <NUM> that is bent or curved between the terminal portion <NUM> and the base portion <NUM>. The intermediate portion <NUM> has an engaging protrusion <NUM> and an engaged recess <NUM> which are respectively protruded and recessed on an axis CL that matches the movement direction of the slider <NUM>. In some cases including the illustrated example, the engaging protrusion <NUM> protrudes moderately frontward. The vertex of the engaging protrusion <NUM> is positioned on the axis CL. The engaged recess <NUM> is moderately recessed frontward. The bottom point of the engaged recess <NUM> is positioned on the axis CL. As shown in <FIG>, the axis CL is positioned at the center of an interspace W10 in the left-right direction between the respective base end surfaces <NUM> of the base portions <NUM> of the left and right coupled fastener elements <NUM>. The axis CL is parallel to an elongated direction of the fastener tape <NUM>. At the engaging protrusion <NUM> of the intermediate portion <NUM>, the front surface of the fastener element <NUM> is bent or curbed in an arc so as to protrude frontward. At the engaged recess <NUM> of the intermediate portion <NUM>, the rear surface of the fastener element <NUM> is bent or curbed in an arc so as to protrude frontward.

As shown in <FIG>, the engaging protrusion <NUM> is positioned frontward beyond the region defined by a width W1 of the base portion <NUM> in the front-rear direction. That is, the frontward-most end of the engaging protrusion <NUM> is positioned forward than the frontward-most end of the base portion <NUM>. On the other hand, the engaged recess <NUM> is positioned nearby the center of the width W1 of the base portion <NUM> in the front-rear direction. In particular, the vertex of the engaging protrusion <NUM> is positioned out of the maximum width W1 of the base portion <NUM>, and the bottom point of the engaged recess <NUM> is positioned within the maximum width W1 of the base portion <NUM>. Note that, the bottom point of the engaged recess <NUM> is positioned within a maximum width W2 of the terminal portion <NUM>. The fastener element <NUM> is bent or curved such that the width of the fastener element <NUM> in the left-right direction would be reduced. Furthermore, undesired interference between to-be-coupled fastener elements <NUM> when the left and right fastener elements <NUM> are coupled would be suppressed, resulting in improved coupling therebetween when the coupling is completed. Note that, in the present specification, only illustrated is a case where the fastener element <NUM> is bent, and omitted is an illustration of a case where the fastener element <NUM> is curved.

In some cases, at least a part of the terminal portion <NUM> is positioned within the maximum width W1 of the base portion <NUM>. In some cases, the terminal surface <NUM> of the terminal portion <NUM> is positioned within the maximum width W1 of the base portion <NUM>.

In some cases, the fastener element <NUM> presents a bent shape of inverted V when viewed in elevation. In some cases, the fastener element <NUM> has first and second bars <NUM>, <NUM>. The boundary between the first and second bars <NUM>, <NUM> may exist on the axis CL. The coupled portion of the first and second bars <NUM>, <NUM> may be equal to the above-described intermediate portion <NUM>. The second bar <NUM> includes the above-described terminal portion <NUM>. The boundary between the first bar <NUM> and the base portion <NUM> may exist on an axis AX that is parallel to the axis CL and positioned at the center in the width of a core thread <NUM> in the left-right direction.

When the left and right fastener elements <NUM> are coupled, the left fastener element <NUM> is sandwiched between the right fastener elements <NUM> located adjacently on the right fastener tape <NUM>. In some cases, the engaging protrusion <NUM> of the left fastener element <NUM> is engaged with the engaged recess <NUM> of the right fastener element <NUM> positioned at the front side. Likewise, the engaged recess <NUM> of the left fastener element <NUM> is engaged with the engaging protrusion <NUM> of the right fastener element <NUM> positioned at the rear side.

When the left and right fastener elements <NUM> are coupled, the front surface of the first bar <NUM> of the left fastener element <NUM> and the rear surface of the second bar <NUM> of the right fastener element <NUM> positioned at the front side may be opposed to or in contact one another. The rear surface of the first bar <NUM> of the left fastener element <NUM> and the front surface of the second bar <NUM> of the right fastener element <NUM> positioned at the rear side may be opposed to or in contact one another.

When the left and right fastener elements <NUM> are coupled, the front surface of the second bar <NUM> of the left fastener element <NUM> and the rear surface of the first bar <NUM> of the right fastener element <NUM> positioned at the front side may be opposed to or in contact one another. The rear surface of the second bar <NUM> of the left fastener element <NUM> and the front surface of the first bar <NUM> of the right fastener element <NUM> positioned at the rear side may be opposed to or in contact one another.

Even when the left fastener element <NUM> is moved leftward when left and right fastener elements <NUM> are coupled, the second bar <NUM> of the left fastener element <NUM> is interfered with the first bar <NUM> of the right fastener element <NUM> positioned at the rear side, and the first bar <NUM> of the left fastener element <NUM> is interfered with the second bar <NUM> of the right fastener element <NUM> positioned at the front side. The same applies to the right fastener elements <NUM> relative to the left fastener elements <NUM>.

In some cases including the presently disclosed examples, an angle θ between the first and second bars <NUM>, <NUM> satisfies <NUM>°<θ<<NUM>°. In a case of <NUM>°>θ, when the left and right fastener elements <NUM> are coupled, the left and right fastener elements <NUM> are interfered with one another, increasing a required force for moving the slider <NUM> or making it impossible to suitably couple them. In a case of θ> <NUM>°, an interspace W3 between adjacent base portions <NUM> of the fastener elements <NUM> located on the same fastener tape <NUM> may be smaller, and the base portions <NUM> of the fastener elements <NUM> located on the same fastener tape <NUM> may be interfered one another or flexibility of the side-edge <NUM> of the fastener tape <NUM> may be lowered.

The relationship between the first and second bars <NUM>, <NUM> applies to the relationship between the front surface of the first bar <NUM> and the front surface of the second bar <NUM> by which the engaging protrusion <NUM> is formed, and similarly applies to the relationship between the rear surface of the first bar <NUM> and the rear surface of the second bar <NUM> by which the engaged recess <NUM> is shaped.

In some cases, a first recess <NUM>, which is different from the above-described engaged recess <NUM>, may be located between the first bar <NUM> and the base portion <NUM> and at the same side as the engaging protrusion <NUM> in the front-rear direction. The first recess <NUM> is a recess that is recessed in the opposite direction of the protruding direction of the engaging protrusion <NUM> at the same side as the engaging protrusion <NUM>. The first recess <NUM> is positioned on the core thread <NUM> of the fastener tape <NUM>. In more detail, the bottom point of the first recess <NUM> may be positioned on the axis AX. The existence of the first recess <NUM> may cause an increase in the maximum width W1 of the base portion <NUM>. As would be appreciated from <FIG>, an interspace W4 between the vertex position of the engaging protrusion <NUM> and the bottom position of the first recess <NUM> in the front-rear direction is substantially equal to an interspace W5 between the rearmost point of the terminal portion <NUM> and the bottom position of the engaged recess <NUM>. That is, the extent of protruding of the engaging protrusion <NUM> and the extent of depth of the engaged recess <NUM> are complementary. Accordingly, facilitated would be better coupling between the left and right fastener elements <NUM> of the same shape. Also, as appreciated from <FIG>, when the left and right fastener stringers <NUM> are coupled, the terminal portion <NUM> of the right fastener element <NUM> enters into the first recess <NUM> of the left fastener element <NUM>. Therefore, in a case where the first recess <NUM> is provided, an engagement angle between left and right fastener elements <NUM> would be greater (or deeper) compared with a case where the first recess <NUM> is not provided, increasing a lateral strength of slide fastener <NUM>.

The front and rear surfaces of the first bar <NUM> extend substantially in parallel between the axis AX and the axis CL, obliquely with respect to the left-right direction. The front and rear surfaces of the second bar <NUM> extend substantially in parallel from the axis CL toward the outward side of fastener tape, obliquely with respect to the left-right direction.

As shown in <FIG>, in some cases, the terminal portion <NUM> of the fastener element <NUM> is provided with an accommodating recess <NUM> that accommodates the core thread <NUM> of the fastener tape <NUM> of the engagement-partner fastener stringer <NUM> when the paired fastener stringers <NUM> are coupled. The accommodating recess <NUM> extends in the front-rear direction, similar to the core thread <NUM>. The accommodating recess <NUM> of the fastener element <NUM> accommodates the core thread <NUM> so that up-down displacement of the terminal portion <NUM> of the fastener element <NUM> at the time of coupling would be effectively restricted. As shown in <FIG>, the accommodating recess <NUM> is located at the center in the thickness of the terminal portion <NUM> in the up-down direction. The terminal surface <NUM> of the terminal portion <NUM> is divided into upper and lower sections by the accommodating recess <NUM>. The upper section of the terminal surface <NUM> touches a side surface of an upper portion of the coupling pillar <NUM> of the slider <NUM>. The lower section of the terminal surface <NUM> touches a side surface of a lower portion of the coupling pillar <NUM> of the slider <NUM>. The depth D26 of the accommodating recess <NUM> which extends in the front-rear direction is less than the width of the core thread <NUM> in the left-right direction.

The fastener element <NUM> may be made of metal, resin or other material. In a case where the fastener element <NUM> is made of metal, the base portion <NUM> of the fastener element <NUM> is bifurcated, and is secured to the side-edge <NUM> of the fastener tape <NUM> through a step of swaging. In a case where the fastener element <NUM> is made of resin, the fastener element <NUM> is secured to the side-edge <NUM> of the fastener tape <NUM> through a step of injection molding performed while the side-edge <NUM> of the fastener tape <NUM> is arranged inside a cavity of a mold. In cases where the fastener element <NUM> is made of other material, it may be secured to the side-edge <NUM> of the fastener tape <NUM> through any suitable manner for that material.

The slider <NUM> has an upper wing <NUM>, a lower wing <NUM>, a coupling pillar <NUM>, and a flange <NUM>. The coupling pillar <NUM> couples the upper wing <NUM> and the lower wing <NUM>, and is opposed to or touched by the terminal surface <NUM> of the terminal portion <NUM> of the fastener element <NUM>. The flange <NUM> is provided at least one of the upper wing <NUM> and the lower wing <NUM>, and is opposed to or touched by the base end surface <NUM> of the base portion <NUM> of the fastener element <NUM>. The slider <NUM> may be made of metal, resin or other material. The slider <NUM> has paired front mouths adjacent at the left and right sides of the coupling pillar <NUM>, and the respective fastener elements <NUM> enter into the slider <NUM> through the front mouths respectively. The left and right fastener elements <NUM> coupled at the inside of the slider <NUM> moves out from the slider <NUM> through one rear mouth of the slider <NUM>. In some cases, the upper wing <NUM> of the slider <NUM> is provided with a pull-attachment column to which any type of pull can be attached.

The upper and lower wings <NUM> and <NUM> are arranged to be opposed one another with an interspace that is equal to the height of the coupling pillar <NUM> in the up-down direction. The distance between the upper and lower wings <NUM> and <NUM> in the up-down direction is slightly greater than the maximum thickness of fastener element <NUM> in the up-down direction.

The coupling pillar <NUM> of the slider <NUM> has a cross-sectional shape of triangle, more precisely an isosceles triangle, having a maximum width at front side and a minimum width at a rear side. The coupling pillar <NUM> has a left-side surface <NUM> and right-side surface 43n which come closer one another rearward. The left-side surface <NUM> is a flat surface, ensuring smooth sliding of the left fastener element <NUM>. The right-side surface 43n is a flat surface, ensuring smooth sliding of the right fastener element <NUM>.

The coupling pillar <NUM> has a rounded rear end 43r. Angle between the left-side surface <NUM> and the right-side surface 43n may be set suitably, e.g. <NUM>-<NUM>° in some cases, and <NUM>° in the presently disclosed example. The coupling pillar <NUM> has a front surface 43f that crosses the front-rear direction at the right angle. Arc surface is provided between the left-side surface <NUM> and the front surface 43f, and arc surface is provided between the right-side surface 43n and the front surface 43f, facilitating smooth sliding of fastener elements <NUM>.

The paired flanges <NUM> of the slider <NUM> have a maximum interspace in the left-right direction at a front side, and a minimum interspace in the left-right direction at the rear side. The paired flanges <NUM> include left and right flanges <NUM> and 44n. The left flange <NUM> has an inner surface 44m1 that is opposed to the right flange 44n. The right flange 44n has an inner surface 44n1 that is opposed to the left flange <NUM>. The base end surface <NUM> of the base portion <NUM> of the left fastener element <NUM> is opposed to, touches or slides on the inner surface 44m1 of the left flange <NUM>. The base end surface <NUM> of the base portion <NUM> of the right fastener element <NUM> is opposed to, touches or slides on the inner surface 44n1 of the right flange 44n.

In some cases including the presently disclosed examples, the upper wing <NUM> and the lower wing <NUM> are respectively provided with the paired flanges <NUM>. That is, the slider <NUM> has a pair of upper flanges provided at the upper wing <NUM> and a pair of lower flanges provided at the lower wing <NUM>. Total <NUM> flanges <NUM> may be provided so that an element passage between the upper wing <NUM> and the lower wing <NUM> would be suitably restricted. In some embodiments, the fastener element <NUM> may have a fin that will enter into a space between the upper and lower flanges. Variation is envisioned where the slider <NUM> has two flanges <NUM> only, in which one flange may possibly be provided at the upper wing <NUM> and the other one may possibly be provided at the lower wing <NUM>.

In some cases including the presently disclosed examples, as shown in <FIG> and <FIG>, in the left-right direction orthogonal to the axis CL, a first distance L1 between the axis CL and the terminal surface <NUM> of the terminal portion <NUM> is less than a second distance L2 between the axis CL and the base end surface <NUM> of the base portion <NUM>. According to such a configuration, a force required for moving the slider <NUM> for coupling the left and right fastener stringers <NUM> would be effectively reduced. In some cases, <NUM><P/Q<<NUM> is satisfied where P indicates the first distance L1; and Q indicates the second distance L2. In a case of <NUM>>P/Q, an element cannot reach at the core thread <NUM> on which an engagement-partner fastener element <NUM> is provided, possibly failing to restrict up-down displacement of the fastener element <NUM> when the elements are coupled. In a case of P/Q><NUM>, a second bar <NUM> of a fastener element <NUM> may possibly be interfered with a fist bar <NUM> of the other fastener element <NUM> when the elements are coupled.

In some cases including the presently disclosed examples, <NUM><2P/T<<NUM> is satisfied where T indicates an interspace W10 in an orthogonal direction (i.e. in the left-right direction) between the respective base end surfaces <NUM> of the base portions <NUM> of the coupled fastener elements <NUM> in the pair of fastener stringers <NUM>. In a case of <NUM>>2P/T, a fastener element <NUM> may not be able to reach a core thread <NUM> on which an engagement-partner fastener element <NUM> is provided, possibly failing to restrict up-down displacement of fastener element when the elements are coupled. In a case of 2P/T><NUM>, a second bar <NUM> of a fastener element may possibly be interfered with a fist bar <NUM> of the other fastener element when the elements are coupled.

In some cases including the presently disclosed examples, in a direction parallel to the axis CL, the maximum width W1 of the base portion <NUM> is greater than the minimum width W2 of the terminal portion <NUM> so that attachment strength of fastener element <NUM> to the fastener tape <NUM> would be increased.

In some cases including the presently disclosed examples, in a direction parallel to the axis CL, <NUM><R/(R+S)<<NUM> is satisfied where R indicates a maximum width W1 of the base portion <NUM>, and S indicates a minimum interspace W3 of adjacent base portions <NUM> of fastener elements <NUM> on the same fastener tape <NUM>. In a case of R/(R+S)><NUM>, the respective base portions <NUM> of adjacent fastener elements <NUM> on the same fastener tape <NUM> may possibly be interfered with one another when the left and right fastener elements <NUM> are coupled. In a case of <NUM> > R/(R+S), attachment strength of a fastener element <NUM> to a fastener tape <NUM> may be lowered and the base end surface <NUM> may not be able to have a sufficient area, possibly deteriorating a stability of posture of fastener element <NUM> inside a slider <NUM>.

Referring to <FIG>, how the right fastener element 20A is coupled to the left fastener element 20B, 20C will be described. As a result of frontward movement of the slider <NUM>, the terminal portion <NUM> of the fastener element 20A enters into a space between the respective terminal portions <NUM> of the fastener elements 20B, 20C as shown in <FIG>. In the fastener elements 20A to 20C, the first distance L1 is less than the second distance L2 as described above. Therefore, the terminal portion <NUM> of the fastener element 20A can smoothly enter into the interspace between the respective terminal portions <NUM> of the fastener elements 20B, 20C. Sufficient interspace is secured between the adjacent base portions <NUM> of fastener elements <NUM> on the same fastener tape <NUM>, and flexibility of posture change of fastener element <NUM> is also secured.

As a result of further frontward movement of the slider <NUM>, the fastener element 20A is pushed by the inner surface of the right flange and moves leftward as shown in <FIG> and <FIG>. Likewise, the fastener element 20B, 20C are pushed by the inner surface of the left flange and move rightward. The terminal portion <NUM> of the fastener element 20A overpasses the engaging protrusion <NUM> of the fastener element 20C. The engaged recess <NUM> of the fastener element 20A and the engaging protrusion <NUM> of the fastener element 20C are engaged. The terminal portion <NUM> and the second bar <NUM> of the fastener element 20B are pushed frontward by the fastener element 20A. The fastener element 20B does not strongly hinder the engagement between the fastener elements 20A and 20C.

As a result of further frontward movement of the slider <NUM>, as shown in <FIG>, the fastener elements 20A to 20C are coupled; the engaging protrusion <NUM> of the fastener element 20A is engaged with the engaged recess <NUM> of the fastener element 20B; the engaged recess <NUM> of the fastener element 20A is engaged with the engaging protrusion <NUM> of the fastener element 20C. The fastener element 20B is pushed rearward when the engaged recess <NUM> of the fastener element 20D positioned next to and at the front side of the fastener element 20A is coupled to the engaging protrusion <NUM> of the fastener element 20B.

As described above, in some cases including the presently disclosed examples, in an orthogonal direction orthogonal to the axis CL (i.e. in the left-right direction), the first distance L1 between the axis CL and the terminal surface <NUM> of the terminal portion <NUM> is less than the second distance L2 between the axis CL and the base end surface <NUM> of the base portion <NUM>. Therefore, as in <FIG>, the left and right fastener elements <NUM> would be suppressed from strongly interfered with one another when the elements are coupled, reducing a force required to pull the slider <NUM> for coupling the left and right fastener elements <NUM>. As described above, in a case where <NUM><P/Q<<NUM> is satisfied, a strength against a force for pulling apart in the left-right direction and a resistance against a thrust in the up-down direction would be suitably ensured while a force for pulling the slider <NUM> is reduced.

Force of <NUM> N was required for moving a slider for coupling fastener elements in an example in which L1: <NUM>, L2: <NUM>, θ: <NUM>°, W1: <NUM>, W2: <NUM>, W3: <NUM>, and angle between left-side and right-side surfaces <NUM>, 43n of the coupling pillar <NUM> of the slider <NUM>: <NUM>°. In the type of slide fastener shown in <FIG>, <FIG> N is required for moving a slider for coupling fastener elements.

In another working example, L1: <NUM>, L2: <NUM>, θ: <NUM>°, W1: <NUM>, W2: <NUM>, W3: <NUM>, and angle between left-side and right-side surfaces <NUM>, 43n of the coupling pillar <NUM> of the slider <NUM>: <NUM>°. Force of <NUM> N was required for moving a slider for coupling fastener elements.

Further aspects of the present disclosure would be described further hereinafter with reference to <FIG>. <FIG> is a schematic and partial elevational view of a slide fastener <NUM> where a slider <NUM> is schematically illustrated by dash-dot line. <FIG> is a schematic and partial elevational view showing coupled left and right fastener stringers <NUM>. <FIG> is a schematic end view taken along a two-dot chain line X12-X12 in <FIG>. <FIG> is a schematic end view taken along a two-dot chain line X13-X13 in <FIG>. <FIG> is a schematic perspective view of a fastener element <NUM> fixed to a fastener tape <NUM>. <FIG> is a schematic elevational view of a fastener element <NUM> fixed to a fastener tape <NUM>. <FIG> is a schematic end view taken along a two-dot chain line X16-X16 in <FIG>, showing a sloped surface <NUM> provided on a terminal portion <NUM> of fastener element <NUM>. <FIG> is a schematic end view taken along a two-dot chain line X17-X17 in <FIG>, showing a locking wall <NUM> provided on a fastener element <NUM>. <FIG> is a schematic front view of a fastener element <NUM> fixed to a fastener tape <NUM>. <FIG> is a schematic rear view of a fastener element <NUM> fixed to a fastener tape <NUM>. <FIG> is a schematic side view of a fastener element fixed to a fastener tape, showing a terminal surface <NUM> of a terminal portion <NUM> of fastener element <NUM>.

Unlike the fastener element <NUM> shown in <FIG>, a fastener element <NUM> of the present <FIG> etc. does not present a bent shape of inverted V when viewed in elevation, but does have an intermediate portion <NUM> that is equivalent to the intermediate portion of the fastener element <NUM> shown in <FIG> and <FIG>. As shown in <FIG>, the intermediate portion <NUM> has an engaging protrusion <NUM> and an engaged recess <NUM> which are respectively protruded and recessed on an axis CL that matches a movement direction of the slider <NUM>. Furthermore, in an orthogonal direction orthogonal to the axis CL (i.e. in the left-right direction), the first distance L1 between the axis CL and the terminal surface <NUM> of the terminal portion <NUM> is less than the second distance L2 between the axis CL and the base end surface <NUM> of the base portion <NUM>. Force required for moving the slider <NUM> for coupling the left and right fastener stringers <NUM> would be effectively reduced, and the slider <NUM> can be moved much easier with lesser force.

There is no change that, when left and right fastener elements <NUM> are coupled, the engaging protrusion <NUM> of the fastener element <NUM> at one side of the left and right sides is engaged or fitted with the engaged recess <NUM> of the fastener element <NUM> of the other side of the left and right sides. In the embodiment disclosed in <FIG>, the fastener element <NUM> included in the fastener stringer <NUM> at one side of the left and right sides can be engaged with the fastener tape <NUM>, more particularly a core thread <NUM> of the fastener stringer <NUM> at the other side of the left and right sides. In contrast, in the disclosed embodiment of <FIG>, the fastener element <NUM> (in particular, a terminal portion <NUM>) at one side of the left and right sides can be engaged with a displacement-restricting portion <NUM> of the (engagement-partner) fastener element <NUM> at the other side of the left and right sides, thus its up-down displacement would be prevented. As the fastener element <NUM> is harder than the core thread <NUM>, the up-down displacement of the fastener element <NUM> would be sufficiently prevented. The left-right length of the fastener element <NUM> would be reduced and the interspace W10 would be reduced. As a result, use of conventional sliders (See <FIG>) would be facilitated without a need of use of dedicated or special sliders (See <FIG>). Avoiding the use of dedicated or special sliders would allow an increased efficiency of manufacturing of slide fasteners (or a reduced burden of management of manufacturing of slide fasteners), or allows to facilitate the reduction of price of slide fastener.

As would be appreciated from <FIG>, the fastener element <NUM> has at least one displacement-restricting portion <NUM> provided adjacent to the intermediate portion <NUM> or a pair of displacement-restricting portion <NUM> arranged to sandwich the intermediate portion <NUM> in the front-rear direction. The displacement-restricting portion <NUM> protrudes from the base portion <NUM> outwardly of fastener tape. The displacement-restricting portion <NUM> positioned at the front side of the intermediate portion <NUM> is provided to occupy at least partially a space between the engaging protrusion <NUM> and the base portion <NUM>. The displacement-restricting portion <NUM> positioned at the rear side of the intermediate portion <NUM> extends from the base portion <NUM> toward the terminal portion <NUM> (a first protuberance <NUM> described below). The displacement-restricting portion <NUM> is provided at the center position or height in the thickness of the base portion <NUM> along the up-down direction, but not necessarily limited thereto. The displacement-restricting portion <NUM> may be referred to as a shoulder in the case of <FIG>.

Various manners are envisioned regarding engagement between the terminal portion <NUM> of the fastener element <NUM> and the displacement-restricting portion <NUM> of the engagement-partner fastener element <NUM>. As shown in <FIG>, the terminal portion <NUM> of the fastener element <NUM> is provided with an accommodating recess <NUM> that accommodates the displacement-restricting portion <NUM>. The accommodating recess <NUM> has a concavity that extends in parallel to the axis CL, but not necessarily limited thereto. Regarding the coupled two fastener elements <NUM>, the accommodating recess <NUM> of the terminal portion <NUM> of one fastener element <NUM> accommodates the displacement-restricting portion <NUM> of the other fastener element <NUM>, thereby preventing displacement of fastener element <NUM> in the up-down direction. For example, the fastener elements <NUM> are prevented from locally decoupled in accordance of flexure of slide fastener <NUM> along the elongated direction thereof, for example. Note that, in one fastener element <NUM>, the accommodating recess <NUM> is positioned away from the base portion <NUM> farther than the engaging protrusion <NUM> and the engaged recess <NUM>.

As shown in <FIG>, in the embodiment where the displacement-restricting portion <NUM> is provided at the center position or height in the thickness of the base portion <NUM> along the up-down direction, the accommodating recess <NUM> is provided at the center position or height in the thickness of the terminal portion <NUM> of the fastener element <NUM> along the up-down direction. The terminal portion <NUM> of the fastener element <NUM> has an upper portion 22p and a lower portion 22q which are arranged to sandwich the accommodating recess <NUM> (See <FIG>).

The rear end of the terminal portion <NUM> of the fastener element <NUM> is provided with a first protuberance <NUM> that protrudes in a direction opposite to the depth direction of the engaged recess <NUM> (i.e. rearward). Alternatively or additionally, the front end of the terminal portion <NUM> of the fastener element <NUM> is provided with a second protuberance <NUM> that protrudes in the same direction as the engaging protrusion <NUM> (i.e. frontward) with an amount of protruding less than an amount of protruding of the engaging protrusion <NUM>. The accommodating recess <NUM> would be elongated longer, facilitating more sufficient engagement between the accommodating recess <NUM> and the displacement-restricting portion <NUM>. In some cases, the upper portion 22p and the lower portion 22q of the terminal portion <NUM> of the fastener element <NUM> are respectively provided with first and second protuberances <NUM>, <NUM>, not necessarily limited to through.

Note that, in view of interrelationship of planes B1, T1 and T2 shown in <FIG>, it would be possible to understand that the second protuberance <NUM> has an amount of protruding that is lesser than that of the engaging protrusion <NUM>. Distance between a plane B1 set at a bottom position of an intermediate recess <NUM> (described below) located between the second protuberance <NUM> and the engaging protrusion <NUM> and a plane T1 set at the vertex of the second protuberance <NUM> is less than a distance between the plane B1 and a plane T2 that is set at the vertex of the engaging protrusion <NUM>. Note that, each of the planes B1, T1 and T2 is a plane that is orthogonal to the axis CL.

Similar to the embodiment shown in <FIG>, the fastener element <NUM> has a first recess <NUM> that is recessed between the engaging protrusion <NUM> and the base portion <NUM> (See <FIG>). Unlike the embodiment shown in <FIG>, the first recess <NUM> is not positioned on the core thread <NUM> but is positioned outwardly of fastener tape than the core thread <NUM>. Regarding two coupled fastener elements <NUM>, the first protuberance <NUM> of the terminal portion <NUM> of one fastener element <NUM> is engaged with the first recess <NUM> of the other fastener element <NUM>. More sufficient engagement of the engaging protrusion <NUM> and the engaged recess <NUM> would be facilitated.

As shown in <FIG>, in an embodiment where the displacement-restricting portion <NUM> is provided at a center position or height in the thickness of the base portion <NUM> along the up-down direction, the first recess <NUM> is divided into upper and lower sections by the displacement-restricting portion <NUM>. As shown in <FIG>, the first recess <NUM> has upper and lower recesses 29p and 29q which are arranged to sandwich the displacement-restricting portion <NUM> in the up-down direction. Regarding two coupled fastener elements <NUM>, the upper portion 22p of the terminal portion <NUM> of one fastener element <NUM> is arranged in the upper recess 29p of the first recess <NUM> of the other fastener element <NUM>. Likewise, the lower portion 22q of the terminal portion <NUM> of one fastener element <NUM> is arranged in the lower recess 29q of the first recess <NUM> of the other fastener element <NUM>. The displacement-restricting portion <NUM> is sandwiched between the upper portion 22p and the lower portion 22q of the terminal portion <NUM> of the fastener element <NUM>. The same explanation as the first recess <NUM> would apply to the second recess <NUM>, and thus overlapping description would be omitted. Note that, the second recess <NUM> has upper and lower recesses 39p and 39q which are arranged to sandwich the displacement-restricting portion <NUM> in the up-down direction.

Unlike the embodiment shown in <FIG>, the fastener element <NUM> has a second recess <NUM> that is recessed at a position between the engaged recess <NUM> and the base portion <NUM> (See <FIG>). The first recess <NUM> and the second recess <NUM> are arranged to sandwich the intermediate portion <NUM> (an extending portion 23j described below) in the front-rear direction. The second recess <NUM> is provided outwardly of fastener tape than the core thread <NUM>. Regarding two coupled fastener elements <NUM>, the second protuberance <NUM> of the terminal portion <NUM> of one fastener element <NUM> is engaged with the second recess <NUM> of the other fastener element <NUM>. More sufficient engagement of the engaging protrusion <NUM> and the engaged recess <NUM> would be facilitated. An intermediate protrusion <NUM> is provided between the engaged recess <NUM> and the second recess <NUM>. When the left and right fastener elements <NUM> are coupled, the intermediate protrusion <NUM> of the front-side fastener element <NUM> enters into the intermediate recess <NUM> located between the second protuberance <NUM> and the engaging protrusion <NUM> of the rear-side fastener element <NUM>, thereby facilitating more sufficient engagement between the second protuberance <NUM> and the second recess <NUM>. The intermediate protrusion <NUM> is projected rearward. The intermediate recess <NUM> is recessed rearward.

As would be understood from the above description, various shapes of fastener elements <NUM> would be envisioned. In some cases, the terminal portion <NUM> of the fastener element <NUM> has a taper portion <NUM> that has a tapered width along a direction from the engaging protrusion <NUM> toward the engaged recess <NUM>. In the illustrated example, the terminal portion <NUM> of the fastener element <NUM> has a pair of sloped surfaces <NUM> that extend along the axis CL, and the paired sloped surface <NUM> come closer one another as extending along the direction from the engaging protrusion <NUM> to the engaged recess <NUM>. Accordingly, lowered would be a possibility that the fastener element <NUM> touches the upper and lower wings <NUM>, <NUM> of the slider <NUM> and, when the slider <NUM> moves frontward while the fastener stringer <NUM> is twisted, it would be suppressed that the fastener elements <NUM> do not enter into the slider <NUM> suitably and smooth movement of the slider <NUM> is hindered. Note that, an embodiment is envisioned where one of the paired sloped surfaces <NUM> is replaced by a flat surface. That is, there is no need for the taper portion <NUM> to be configured symmetrically with respect to a plane such as a plane parallel to the fastener tape <NUM>.

The sloped surface <NUM> may provide a sliding surface for a locking pawl <NUM> that may be incorporated into the slider <NUM>, in addition to or as an alternative to facilitate smooth entering of fastener elements <NUM> into the slider <NUM>. Concretely, the locking pawl <NUM> incorporated into the slider <NUM> slides on the sloped surfaces <NUM> when the slider <NUM> moves frontward. Accordingly, the movement of the slider <NUM> into which the locking pawl <NUM> is incorporated would be smoother. For this purpose, the sloped surface <NUM> extends to cross the axis CL in the left-right direction. Accordingly, the locking pawl <NUM>, designed to move along the axis CL, would be allowed to slide on the sloped surface <NUM> smoothly. Additionally or alternatively, the sloped surface <NUM> extends from the terminal portion <NUM> toward the base portion <NUM> of the fastener element <NUM>. As a further addition or alternative, the sloped surface <NUM> is formed across the terminal portion <NUM> and the intermediate portion <NUM> of the fastener element <NUM>. In other words, the sloped surface <NUM> includes a first region included in the terminal portion <NUM> of the fastener element <NUM> and a second region included in the intermediate portion <NUM>. In the illustrated example, the sloped surface <NUM> is a sloped surface that is slanted downward along a direction from the front-side to the rear-side and formed across the terminal portion <NUM> and the intermediate portion <NUM>. When the slider <NUM> moves frontward, the locking pawl <NUM> can easily ride over the fastener element <NUM> or the fastener element <NUM> can be protected from being scratched by the locking pawl <NUM>.

In some cases, the fastener element <NUM> has a locking wall <NUM> by which the locking pawl <NUM> of the slider <NUM> can be locked, and the engaging protrusion <NUM> protrudes (frontward) from the locking wall <NUM>. The locking wall <NUM> may be formed, for example, by providing a recess at the upper or lower surface of the intermediate portion <NUM> of the fastener element <NUM> or by forming the engaging protrusion <NUM> at the extending portion 23j of the intermediate portion <NUM> (described below). The locking pawl <NUM> of the slider <NUM> is urged downward by an elastic member such as a leaf spring within the slider <NUM>. The locking pawl <NUM> of the slider <NUM> can be moved upward in accordance with operation of the pull tab of the slider <NUM>. When human nips the pull tab of the slider <NUM> and moves the slider <NUM>, the locking pawl <NUM> of the slider <NUM> can ride over the locking wall <NUM>. As would be appreciated from <FIG>, the engaging protrusion <NUM> may have a size in the up-down direction that is greater than the width of the accommodating recess <NUM> in the up-down direction. Even when the locking wall <NUM> is provided, more sufficient engagement between the engaging protrusion <NUM> and the engaged recess <NUM> would be facilitated.

Segmentation of the base portion <NUM>, the terminal portion <NUM>, and the intermediate portion <NUM> is illustrated in <FIG>, but not necessarily limited thereto. The base portion <NUM> is a portion secured to the fastener tape <NUM>. The terminal portion <NUM> is provided at the opposite side relative to the base portion <NUM> in the fastener element <NUM> that extends away from the fastener tape <NUM>. The intermediate portion <NUM> is provided between the base portion <NUM> and the terminal portion <NUM>. Likewise the embodiment shown in <FIG>, the fastener element <NUM> includes a bent or curved portion between the terminal portion <NUM> and the base portion <NUM>. In the illustrated example, the fastener element <NUM> includes the first and second bars <NUM>, <NUM> (See <FIG>). In the illustrated example, as shown in <FIG>, the intermediate portion <NUM> includes the extending portion 23j that extends from the base portion <NUM> toward the terminal portion <NUM>. The engaging protrusion <NUM> protrudes frontward from the front surface of the extending portion 23j of the intermediate portion <NUM>. The engaged recess <NUM> is a recess provided at the rear surface of the extending portion 23j of the intermediate portion <NUM>.

The front surface of the extending portion 23j of the intermediate portion <NUM> extends so as to shape the first recess <NUM>, the locking wall <NUM> and the second protuberance <NUM>. The rear surface of the extending portion 23j of the intermediate portion <NUM> extends so as to shape the second recess <NUM>, the intermediate protrusion <NUM>, the engaged recess <NUM> and the first protuberance <NUM>. Note that, the locking wall <NUM> is a part of the front surface of the extending portion 23j of the intermediate portion <NUM>. Note that, the front-side displacement-restricting portion <NUM> is coupled to the front surface of the extending portion 23j of the intermediate portion <NUM>. The rear-side displacement-restricting portion <NUM> is coupled to the rear surface of the extending portion 23j of the intermediate portion <NUM>.

Similar to the embodiment shown in <FIG>, the engaging protrusion <NUM> includes an angular portion positioned on the axis CL, and the engaged recess <NUM> includes a concavity that is positioned on the axis CL and is shaped complementary to the angular portion 24c. In some cases, the engaging protrusion <NUM> is configured to have a width in the left-right direction that is narrowed toward the front-side and, for example it is V-shaped by the pair of sloped surfaces 24a, 24b. The paired sloped surfaces 24a, 24b come closer as extending frontward along the axis CL. One sloped surface 24a is slanted frontward as extending along a direction from the base portion <NUM> toward the terminal portion <NUM>. The other sloped surface 24b is slanted frontward as extending along a direction from the terminal portion <NUM> toward the base portion <NUM>. Cross point of the paired sloped surfaces 24a, 24b is at a vertex of the V-shaped engaging protrusion <NUM> (the angular portion). The vertex of the V-shaped engaging protrusion <NUM> may be positioned on the axis CL. Similarly, the engaged recess <NUM> is configured to be narrower in the left-right direction toward the front-side and, for example is defined to be V-shaped by a pair of sloped surfaces 25a, 25b. The paired sloped surfaces 25a, 25b come closer one another as extending frontward along the axis CL. One sloped surface 25a is slanted frontward as extending along a direction from the base portion <NUM> toward the terminal portion <NUM>. The other sloped surface 25b is slanted frontward as extending along a direction from the terminal portion <NUM> toward the base portion <NUM>. Cross point of the paired sloped surfaces 25a, 25b is at a bottom point of the V-shaped engaged recess <NUM> (the concavity). The bottom point of the V-shaped engaged recess <NUM> may be positioned on the axis CL.

The paired sloped surfaces 24a, 24b of the engaging protrusion <NUM> are substantially symmetrical with respect to the axis CL. Likewise, the paired sloped surfaces 25a, 25b of the engaged recess <NUM> are substantially symmetrical with respect to the axis CL. Furthermore, the sloped surfaces 24a, 25a are in parallel one another at least partially, and the sloped surfaces 24b, 25b are in parallel one another at least partially. Based on such features, it would be readily appreciated that the fastener element <NUM> includes the first and second bars <NUM>, <NUM> similar to the embodiment shown in <FIG>. That is, the first and second bars <NUM>, <NUM> shown by dotted lines in <FIG> are included in the fastener element <NUM>. The angle θ between the first and second bars <NUM>, <NUM> satisfies <NUM>°<θ<<NUM>°.

The second protuberance <NUM> protrudes frontward from the front surface of the second bar <NUM>. The second recess <NUM> is formed at the rear surface of the first bar <NUM>. Engagement of the second protuberance <NUM> and the second recess <NUM> increases the resistance of the slide fastener <NUM> against a lateral pulling force.

Here, with reference to <FIG>, we are going to consider about a difference between conventional and presently disclosed fastener elements. <FIG> shows a fastener element <NUM> according to the present disclosure, and <FIG> shows a conventional fastener element <NUM>'. The conventional fastener element <NUM>' has a base portion <NUM>', a head portion <NUM>' and a neck portion <NUM>'. It would be appreciated that a protruded portion <NUM>' extending frontward in the head portion <NUM>' of the conventional fastener element <NUM> is shifted toward the base portion <NUM>' as illustrated by an arrow to arrive at a position where the engaging protrusion <NUM> of the presently disclosed fastener element <NUM> is located. That is, in the presently disclosed fastener element <NUM>, the engaging protrusion <NUM> is provided at a position shifted closer to the base portion <NUM> than the first protuberance <NUM> in the left-right direction, and the first recess <NUM> is provided at a position shifted closer to the base portion <NUM> than the engaged recess <NUM> in the left-right direction. Therefore, even when a force required for moving the slider <NUM> is reduced, it would be possible to facilitate that the strength of slide fastener <NUM> against a lateral pulling force is improved.

The engaging protrusion <NUM> is a frontward-most protruding portion in the terminal portion <NUM> and the intermediate portion <NUM> of the fastener element <NUM>, and has a front-side vertex A. The first protuberance <NUM> is a rearward-most protruding portion in the terminal portion <NUM> and the intermediate portion <NUM> of the fastener element <NUM>, and has a rear-side vertex B. Furthermore, the engaged recess <NUM> is a frontward-most recessed portion in the terminal portion <NUM> and the intermediate portion <NUM> of the fastener element <NUM>, and has a rear-side bottom point C. The first recess <NUM> is a rearward-most recessed portion in the terminal portion <NUM> and the intermediate portion <NUM> of the fastener element <NUM>, and has a front-side bottom point D. Interspace W11 between a first plane parallel to the axis CL and including the vertex A and a second plane parallel to the axis CL and including the vertex B is equal to an interspace W12 between a third plane parallel to the axis CL and including the bottom point C and a fourth plane parallel to the axis CL and including the bottom point D. Likewise, the interspace between the first and fourth planes is equal to the interspace between the second and third planes.

When the left and right fastener elements <NUM> are coupled, the engaging protrusions <NUM> and the engaged recesses <NUM> of the respective left and right fastener elements <NUM> are arranged on the same axis. Similarly, the first protuberances <NUM> and the first recesses <NUM> of the respective left and right fastener elements <NUM> are arranged on the same axis. According to such an aspect, an interference caused when one of left and right fastener elements <NUM> enters into a space between the other ones of left and right fastener elements <NUM> would be reduced, and the following coupling between the left and right fastener elements <NUM> would be strengthened.

In the front-rear direction, the bottom point F of the second recess <NUM> is positioned between the bottom point C of the engaged recess <NUM> and the vertex B of the first protuberance <NUM>. In the front-rear direction, the bottom point E of the intermediate recess <NUM> is positioned between the vertex A of the engaging protrusion <NUM> and the bottom point D of the first recess <NUM>.

Note that, as appreciated from <FIG>, similar to the embodiment shown in <FIG>, an interspace W4 between the bottom point of the first recess <NUM> and the vertex position of the engaging protrusion <NUM> in the front-rear direction is substantially equal to an interspace W5 between the bottom position of the engaged recess <NUM> and the rearmost point of the terminal portion <NUM> (the first protuberance <NUM> in particular).

<FIG> is a schematic elevational view of a fastener element. As shown in <FIG>, the locking wall <NUM> by which the locking pawl <NUM> of slider <NUM> can be locked extends up to the terminal surface <NUM> of the terminal portion <NUM> of the fastener element <NUM>. According to such an aspect, even in a condition shown in <FIG>, engagement between the locking pawl <NUM> and the locking wall <NUM> would be ensured, and stop positions for the slider <NUM> can be set with narrower pitch. The locking pawl <NUM> can touch the respective locking walls <NUM> of both left and right fastener elements <NUM>. When the movement direction of the slider <NUM> matches a vertical direction, after the slider <NUM> is moved frontward and released, the locking pawl <NUM> can touch the locking walls <NUM> of either one of the left and right fastener elements <NUM>, thus hindering rearward movement of the slider <NUM>. The fastener element <NUM> has a non-flat curved surface <NUM> that is directed rearward gradually as extending from the engaged recess <NUM> toward the first protuberance <NUM>, thereby increasing the strength of slide fastener <NUM> against a lateral pulling force.

Further description will be followed with reference to <FIG>. <FIG> is a schematic and partial elevational view showing coupled left and right fastener stringers <NUM> of a slide fastener <NUM>, the base portion <NUM> of fastener element <NUM> having first and second legs <NUM>, <NUM>. <FIG> is a schematic end view taken along a two-dot chain line X24-X24 in <FIG>. <FIG> is a schematic end view taken along a two-dot chain line X25-X25 in <FIG>. <FIG> is a schematic elevational view of a fastener element <NUM> fixed to a fastener tape <NUM>. <FIG> is a schematic end view taken along a two-dot chain line X27-X27 in <FIG>. <FIG> is a schematic end view taken along a two-dot chain line X28-X28 in <FIG>.

In the present embodiment, the base portion <NUM> is configured to cause an opposite rotational moment to reduce a rotational moment caused in accordance with engagement of the engaging protrusion <NUM> and the engaged recess <NUM>, when the pair of fastener stringers <NUM> are pulled apart laterally. Looking at the fastener elements <NUM> labelled by 20F, <NUM> and <NUM> in <FIG>, when the paired fastener stringers <NUM> are pulled apart laterally, a position P1 where the engaging protrusion <NUM> of the fastener element 20F receives a force F1 from the terminal portion <NUM> of the fastener element <NUM> is different from a position P2 where the terminal portion <NUM> of the fastener element 20F receives a force F2 from the engaging protrusion <NUM> of the fastener element <NUM> in the left-right direction. As a result, a rotational moment is caused which rotates the fastener element 20F clockwise. The base portion <NUM> is configured to cause a rotational moment that is opposite and to reduce this rotational moment.

When the paired fastener stringers <NUM> are pulled apart laterally, the right fastener stringer <NUM> is pulled apart from the left fastener stringer <NUM>, and the left fastener stringer <NUM> is pulled apart from the right fastener stringer <NUM>. The coupled fastener elements <NUM> each is pulled outward in the left-right direction by the core thread <NUM> of the fastener tape <NUM> to which it is coupled. In a case where the base portion <NUM> is provided with at least one notch <NUM> that reaches the core thread <NUM> of the fastener tape <NUM>, a distribution of force applied from the core thread <NUM> to the base portion <NUM> of the fastener element <NUM> would be fluctuated along a direction the core thread <NUM> extends. The notch <NUM> is positioned appropriately so that an oppositely-directed rotational moment is caused which allows the fastener element 20F to rotate counterclockwise when the paired fastener stringers <NUM> are pulled apart laterally. In some cases, at least a portion 17e of the core thread <NUM> at the side of the base end surface <NUM> of the base portion <NUM> is exposed through the notch <NUM>.

The notch <NUM> extends from the base end surface <NUM> toward the terminal portion <NUM> until it reaches the core thread <NUM> so that the upper surface of the fastener tape <NUM> is exposed. As a result, the base portion <NUM> has a first leg <NUM> provided at a side of the engaged recess <NUM> (i.e. at rear-side) and a second leg <NUM> provided at a side of the engaging protrusion <NUM> (i.e. at front-side). The first leg <NUM> and the second leg <NUM> are provided to sandwich the notch <NUM>. The contact area of the first leg <NUM> with the fastener tape <NUM> is greater than the contact area of the second leg <NUM> with the fastener tape <NUM>. The width W51 of the first leg <NUM> along the extending direction of the core thread <NUM> is greater than the width W52 of the second leg <NUM>. In some cases, the following condition is satisfied so that magnitude of rotational moment would be set appropriately.

In the embodiment shown in <FIG>, the fastener element <NUM> has individual features such as the first protuberance <NUM>, the second protuberance <NUM>, the locking wall <NUM>, the sloped surface <NUM>, the first recess <NUM> and the second recess <NUM>, but embodiments are envisioned where one or more selected features are omitted.

In the embodiment shown in <FIG> and <FIG>, the first leg <NUM> is partially thinned in a region at the side of the second leg <NUM> such that the width of the first leg <NUM> appears to be reduced. In other words, the first leg <NUM> has a recess (or step) <NUM> provided at the side of the second leg <NUM>, so that the first leg <NUM> appears to have a reduced width <NUM>' from the width W51. Accordingly, the first and second legs <NUM>, <NUM> appear to extend with equivalent or closer widths. This avoids a problem that the base portion <NUM> appears to be asymmetry as a result of that the notch <NUM> is provided at the side of the second leg <NUM> so as to cause a rotational moment opposite to the rotational direction the fastener element <NUM> rotates when the paired fastener stringers <NUM> are pulled apart in the left-right direction, for example. Note that the step surface <NUM> of the recess <NUM> should not be limited to a horizontal surface and may be a sloped surface. As shown in <FIG>, the notch <NUM> may be provided such that the first leg <NUM> only exists. As shown in <FIG>, additionally or alternatively to the notch <NUM>, a hole <NUM> may be provided at a position closer to a front side of the base portion <NUM>. Even in such a case, it is expected that a similar result is obtained as described above based on the same principle described above. An embodiment is envisioned where the notch <NUM> or the hole <NUM> is provided at only one side of the upper and lower sides of the fastener element <NUM> relative to the fastener tape <NUM>.

In an embodiment shown in <FIG>, the fastener element <NUM> is configured differently i.e. to have different shapes in an upper half <NUM> at the side of upper surface of the fastener tape <NUM> and a lower half <NUM> at the side of lower surface of the fastener tape <NUM>. In one sense, the fastener element <NUM> is configured to be asymmetry, i.e. have asymmetrical shapes with respect to a plane where the fastener tape <NUM> exists. The upper half <NUM> of the fastener element <NUM> has a rectangular contour, taking a design functionality of fastener element <NUM> (See <FIG>), not necessarily limited to this though. In contrast, the lower half <NUM> of the fastener element <NUM> has the base portion <NUM>, the terminal portion <NUM> and the intermediate portion <NUM> similarly as described above, taking a coupling functionality of fastener element <NUM>. Even in such a case, the same effect as described above would be obtained unless there is no inconsistency.

The upper half <NUM> of the fastener element <NUM> has a cover <NUM> that covers an interspace between the left and right fastener tape <NUM>. The cover <NUM> protrudes from the fastener tape <NUM> outwardly of fastener tape. When the left and right fastener stringers <NUM> are closed, the upper halves <NUM> of adjacent fastener elements <NUM> in the left-right direction are in contact with or engaged with one another. The cover <NUM> may include one or more or a pair of displacement-restricting portions <NUM>. In one fastener element <NUM>, the intermediate portion <NUM> of the lower half <NUM> of the fastener element <NUM> is coupled to the cover <NUM> of the upper half <NUM> of the fastener element <NUM>. The engaging protrusion <NUM> of the intermediate portion <NUM> either is coupled to the cover <NUM> of the upper half <NUM>. The extending portion 23j of the intermediate portion <NUM> of the lower half <NUM> extends from the base portion <NUM> farther than the cover <NUM> of the upper half <NUM>. The terminal portion <NUM> of the lower half <NUM> is positioned farther from the base portion <NUM> than the cover <NUM> of the upper half <NUM>. Regarding coupled two fastener elements <NUM>, a displacement-restricting portion <NUM> of one fastener element <NUM> is placed onto the upper surface <NUM> of the intermediate portion <NUM> and the terminal portion <NUM> of the other fastener element <NUM>.

In a slide fastener <NUM> according to the embodiment shown in <FIG>, as an additional or alternative of the slider <NUM> shown in <FIG>, an additional or alternative slider <NUM> can be included that may close the left and right fastener stringers <NUM> by moving in the opposite direction (i.e. rearward in the movement direction of the slider <NUM>) relative to the slider <NUM> shown in <FIG>.

Following inventions are also disclosed in the present disclosure. Individual features or combinations of individual features can be applied to the respective inventions described in the appendix below.

Claim 1:
A slide fastener (<NUM>) comprising:
a pair of left and right fastener stringers (<NUM>) wherein each fastener stringer (<NUM>) includes a fastener tape (<NUM>) and a plurality of fastener elements (<NUM>) attached to the fastener tape (<NUM>), each fastener element (<NUM>) including a base portion (<NUM>) secured to the fastener tape (<NUM>) and a terminal portion (<NUM>) positioned opposite to the base portion (<NUM>); and
at least one slider (<NUM>) for opening and closing the pair of left and right fastener stringers (<NUM>), wherein
each of the fastener elements (<NUM>) at the left and right sides has an intermediate portion (<NUM>) including bent or curved portion between the terminal portion (<NUM>) and the base portion (<NUM>),
the intermediate portion (<NUM>) has an engaging protrusion (<NUM>) and an engaged recess (<NUM>) which are respectively protruded and recessed on an axis (CL) that matches a movement direction of the slider (<NUM>), and
the fastener element (<NUM>) at one side of the left and right sides has at least one displacement-restricting portion (<NUM>) that prevents displacement, along an up-down direction, of the fastener element (<NUM>) at the other side of the left and right sides, characterized in that:
the terminal portion (<NUM>) of the fastener element (<NUM>) is provided with a second protuberance (<NUM>) protruding in a same direction as the engaging protrusion (<NUM>) with an amount of protruding less than an amount of protruding of the engaging protrusion (<NUM>).