Ykk Corporation

Shigeru Imai

Yoshihiro Kousaka

Takashi Kato

A coil-shaped fastener element is comprised of a coupling head bulging to both sides, upper/lower leg portions adjacent the coupling head and a connecting portion for connecting the upper and lower leg portions. With providing a stepped portion in a center of the upper leg portion, a portion of the fastener element on a side of the coupling head is formed thick while a portion thereof on a side of the connecting portion is formed thin. A coupling space is provided between the upper and lower leg portions. A protruded portion protruded into the coupling space is provided in a back of the stepped portion of the upper leg portion. A slope portion is formed such that the coupling space is expanded from an inside of an upper portion of the coupling head to a base portion of the protruded portion. A core thread is inserted between the upper and lower leg portions and sewed using a sewing yarn of multi-thread chain stitches as fixing yarn, such that a side edge of the core thread is protruded toward the coupling head. Upon coupling, the coupling head is allowed to be inserted quickly along the slope portion and an excessive insertion of a mating coupling element is prevented by the protruded portion and core thread so as to stabilize the coupling. Thus, the linear slide fastener enables a smooth and quick coupling operation.

Linear slide fastener

The present invention provides an apparatus for manufacturing a slide fastener spiral continuous element row wherein a monofilament is carried on a mandrel while ensuring an accurate pitch of elements even in a high-speed operation and a stepped form of an upper leg portion can be accurately formed at a predetermined portion of each the element. In order to continuously manufacture the slide fastener spiral element row from the continuous monofilament made of synthetic resin, the monofilament transferred continuously is wound spirally around the mandrel and carried while being retained between screw grooves of opposed screws. Then, a coupling head is formed by hitting a portion of the spiral monofilament carried on the mandrel by a pressing roller, the portion corresponding to the coupling head. After that, a stepped upper leg portion is formed by pressing a portion of the spiral monofilament by a rotary hammer at a predetermined position on the mandrel, the portion corresponding to the upper leg portion.

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Toyama-ken, Japan

Shigeru Imai