Slide clasp fastener

Dec. 23, 1969

TADAO YOSHIDA

SLIDE CLASP FASTENER

3,484,906

Filed March 6, 1968

<img file="US3484906A_D0001.tif" />

<img file="US3484906A_D0002.tif" />

<img file="US3484906A_D0003.tif" />

^f0

22 // 43 /3 //

<img file="US3484906A_D0004.tif" />

/2

17 /5 25 G

<img file="US3484906A_D0005.tif" />

<img file="US3484906A_D0006.tif" />

<img file="US3484906A_D0007.tif" />

<img file="US3484906A_D0008.tif" />

United States Patent Office

3,484,906

Patented Dec. 23, 1969

3,484,906 SLIDE CLASP FASTENER Tadao Yoshida, 171 3-chpme, Tamagawa-Yoga-cho, Setagaya-ku, Tokyo, Japan Filed Mar. 6, 1968, Ser. No. 711,120 Int. CI. A44b 19/14

U.S. Cl. 24—205.1 4 Claims

ABSTRACT OF THE DISCLOSURE

A sliding clasp fastener of the concealed type having rows of interlocking plastics elements secured to the folded edges of a pair of carrier tapes. Each element has one leg shorter than the other for sliding engagement with the slider. The slider has its free edge terminated short of the tape surface wthout extending into the folds of the tapes.

This invention relates to sliding clasp fasteners or zippers, and has particular reference to a sliding clasp fastener of the concealed type which substantially simulates a garment seam in its closed position.

Sliding clasp fasteners having two rows of interlocking elements formed from a single plastic filament and secured to the folded edges of a pair of opposed carrier tapes are well known, and such fasteners when closed by a reciprocating slider mask the elements from external view, only leaving a linear seam in the junction of the opposed tapes.

Fasteners of this type have the slider mounted with its free edges inserted in between the folds of the tapes. This arrangement not only renders the movement of the slider rather sluggish, but also gives a tendency for the slider to rub against the folded portions of the tapes and the stitchings that hold the elements thereto.

Whereas, it is an object of the present invention to provide a novel sliding clasp which will eliminate the above noted difficulties.

Briefly stated, the fastener according to this invention comprises a pair of carrier tapes each having an inwardly folded edge portion, a row of meandering fastener elements formed from a single plastics filament and secured to the edge portion of each of said carrier tapes, and a slider slidably mounted on said carrier tapes for coupling and uncoupling said fastener elements, each fastener element'including a coupling head, two legs one shorter than the other, and connecting portions, and said slider having a guide channel configured to embrace the connecting portion continguous to the long leg, a flank portion abutting the connecting portion of the short leg, and free edges terminating short of the tape surface without extending into the folded edge portions of the respective tapes. For a better understanding of the invention, there are presented in the drawings preferred forms which accomplish the object of the invention. In the accompanying drawings:

FIG. 1 is a transverse cross-sectional view illustrating one embodiment of the invention;

FIG. 2 is a transverse cross-sectional view illustrating the second embodiment of the invention; and

FIGS. 3α and 3b are respectively a plan and a front elevational view of the interlocking fastener element chain employed in the construction of the concealed fastener of the invention, while FIG. 3c is a partly sectional side view of one of the elements of said chain.

Reference to FIG. 1 shows a pair of carrier tape stringers 10 each having an inwardly folded edge portion 11 to which a row of interlocking fastener elements 12 are secured by stitching 13. A chain of these elements 12 are formed from a single plastics filament, such as nylon, into a meander structure in which each element has a base portion 14 deformed to provide a coupling head 15 for engagement with a corresponding part of the adjacent mating interlocking element.

The element 12 according to the invention is provided with two leg or limb portions, of which the upper leg 16 abutting the bottom surface of the folded tape portion is shorter in length than the lower leg 17, as clearly seen from FIG. 3α. To conform cooperatively with this alter10 nately short and long limb structure of the element chain, there is proposed a slider 18 having guide channels 19 configured in conformity with the round periphery of the connecting portion 20 of each long-leg element which lies opposite to the coupling head portion 15, and guide flanks 15 21 spaced apart by a distance determined by the total length of the two adjacent short-leg elements in their coupled disposition. It is preferred for the purposes of the invention to terminate the free edges 22 of the slider 18 normally at a point at least apart from the tape surface 20 without having them inserted in between the folds of the respective carrier tapes, as shown in FIGS. 1 and 2.

With this construction, the slider 18 operates to close the two opposed carrier tape's, when the connecting portions 20 of the long-leg elements 17 are guided embrac25 ingly by and in sliding contact with the walls of the guide channels 19, while the connnecting portions 20 of the short-leg elements are similarly guided by the flanks 21 of the slider. In this way, contrary to conventional fastener constructions of the concealed fashion, the slider accord30 ing to the invention does not forcibly contact the frictionally resistant fabric system of the tape or the stitchings holding the elements to the folded edge portions of the tapes. This facilitates the sliding motion of the slider with the added fact that the inner guide walls thereof 35 are maintained in sliding engagement with the least frictionally resistant surfaces of the plastics elements during coupling and uncoupling operation.

In the first embodiment shown in FIG. 1, there is provided a spacing braid 23 inserted between the upper and 4° lower legs of the elements and extending longitudinally of the entire fastener. The provision of this braid serves to hold the elements from shifting out of position with respect to the stitchings when lateral load is applied to the closed tape juncture.

While the problem of wear has been considered of the tape and of the upper sewing threads securing the shortleg elements to the folded edge portions of the tapes, there is further provided means for preventing wear of the lower sewing threads which would otherwise occur ⁵⁰ in contact with the base wall of the slider. This wear preventing means is revealed in the first embodiment, FIG. 1, as a pair of longtiudinal recesses 24 formed in the base wall of the slider. In the second embodiment, FIG. 2, it is revealed as grooves 25 formed in the lower ⁵⁵ legs 17.

In addition to the various advantages of the invention that have been advanced, it will be understood that since the free edges of the slider terminate short of the tape surface and do not extend into the folds of the tape ^U stringers, the thickness of the slider is so much reduced as compared with conventional counterparts, which, as a result, will facilitate ironing the garment to which the fastener is attached.