GB547663A - Improved separable fastener - Google Patents

Abstract

547,663. Sliding-clasp fasteners. WAHL BROS., Inc. March 5, 1940, No. 4061. Convention date, Feb. 16, 1939. [Class 44] In a sliding-clasp fastener having interlocking spirals 9, 10 the material of the spirals, preferably " plastic," is of uniform segmental crosssection, the straight position of the section being disposed internally and oblique with respect to the axis of the spiral. The coils are somewhat flattened to provide elongated " loops" which interengage over more than half their major dimension. The gap between adjacent turns is slightly less than the width of the coil material measured parallel two the length of the stringer. The spirals are of non-uniform pitch, the transverse end portions of the " loops" which are presented towards the other spiral having a smaller pitch angle than that of the adjacent side portions. The spirals may be connected to the tapes 5, 6 by cords 7, 8 passed through the coils and stitched to the tapes, or the turns of the coils may be passed through ladder-like apertures in the tape which is then folded longitudinally in known manner. When the stringers are to be entirely separable the turns of each spiral near the end are less elongated so that they do not interlock, these ends being secured in end fittings 34, 32, Figs. 12, 13, the latter being removably inserted in the former.