Patent GB-740975-A (GB)
Title: Covered slide fastener
IPC: A44B19/04
Filed: 1952-08-26
Abstract: 740,975. Sliding-clasp fasteners. SECO SOC. ANON. BRIG SOC. POUR L'ETUDE ET LA CONSTRUCTION D'ENTREPRISES INDUSTRIELLES. Aug. 26, 1952 [Sept. 3, 1951], No. 21421/52. Class 44. [Also in Group XXII] In a covered slide fastener, Fig. 2, integral angular pointed projections 7, 8 on the coupling part 4 and the free end 6 of each fastener member, each have a first lateral face defining, with the associated leg of the fastener, a triangular recess, and a second lateral face, the second lateral faces being parallel to each other, and the projections 7, 8 deform the bead 2 of the stringer tape 1 so that the bead is compressed at the tips of the projections and expanded into the recesses. Fig. 3 shows a fastener member prior to fitting to the bead 2, the coupling part 4 having a projection 9 and a complementary recess 10, Fig. 5. A hook 5 is formed by a coupling leg 3 and an attaching leg, the free end 6 of which is adapted to overlap the part 4 and to co-operate with a set-back surface thereon. The fastener members on one tape 1, Fig. 2, are mirror images of those on the other tape 1. Accoridng to the embodiments of Figs. 6 and 7 (not shown) the centre part of the hook 5 is weakened to facilitate bending of the attaching leg, by imparting a polygonal shape to the inner edge of the hook at this centre part. Manufacture is effected in a continuous process, the fastener members being punched out of a strip of metal with parallel edges and finally clamped to a stringer tape positioned at right angles with respect to the direction of movement of the strip and also movable longitudinally. In the embodiment of Fig. 8, the strip 21 having parallel edges 13, 14 is moved to a station 15 where the coupling recess 10 and projection 9 are stamped out. At station 16, a recess 17 having a part 18 is punched out of the strip. At station 19, a recess 20 and recess 24 are stamped out of the opposite sides of the strip and a cut 23 made, to form the projections 7, 8, the end 6, and edges 21, 25 of a coupling part of one fastener member and to form the rear edge 22, 26 of the hook of the preceding fastener member. At the same time the preceding fastener member is severed from the strip. The severed members remain within a guideway which embraces them laterally and are pushed forward by the movement of the strip 12. On reaching station 27, the attaching leg is spread apart from the coupling leg 3 by a punch introduced obliquely in a direction opposite to the movement of the strip. Finally, at station 28, the tape 1 is introduced into the hook opening and the attaching leg is pressed towards the coupling leg to embrace the bead 2. Thereafter the tape is moved vertically downwards by a distance equal to that between fastener members on a tape. In the embodiment of Fig. 10, a tongue 32 is finally upset at a station 34 to form the end 6 and projection 8. In the embodiment of Fig. 14, complementary pairs of projections 9 and recesses 10 are each formed side by side on opposite surfaces of the strip at station 37. At station 38 two recesses 39 are stamped-out while at station 41 recesses 42 are cut out and a pair of mirror image fasteners are severed from the strip. At station 43 the two fastener members are separated by two transverse cuts and a cut along the centre line of the strip. In other embodiments described with reference to Figs. 16 to 26 (not shown) the length of a fastener member corresponds to the width of the strip and in one form (Fig. 21, not shown) the members are stamped out in mirror-like pairs and finally separated. In this case two stringer tapes are.inserted into the fastener hook openings in directions diverging from the centre of symmetry of a pair of members.