GB713108A - Improved method and means for making slide fasteners - Google Patents

Abstract

713,108. Moulding. sliding-clasp fasteners. RI-RI-WERK AKT.-GES. Dec. 11, 1951 [Dec. 14, 1950], No. 28981/51, Class 87 (2) [Also in Group XXV] In a method of moulding sliding-clasp fasteners in which a stringer tape is clamped in a dieblock and fastener elements are injectionmoulded in a row along one edge of the tape, that portion of the tape that is disposed outside the cavities in which the elements are moulded is stretched prior to and during the moulding by means disposed in the die-block. This stretching compensates for shrinkage of the tape after moulding. Figs. 1, 2 and 3 show a die block comprising mating dies 1, 2 having shallow recesses 11, 12 which receive the flat parts of two stringer tapes. These recesses have rack-shaped parts 16, 17 which, when the dies 1, 2 are pressed together, clamp the tapes and stretch them. In a modification, Fig. 4, the rack-shaped parts are replaced by undulating parts 16<1>. 17<1>. The parts 16, 17 are separate from the dies, the part 16 being secured to die 1 by screws 18 and the part 17 to the die 2 by grub-screws 19 and springs 20. As shown in Fig. 3, the parts 17 have been pushed, against the action of their springs, towards parts 16 to clamp the tape. This pushing is effected by studs 25 forming part of an injection-moulding machine. In modifications both parts 16, 17 may be resiliently mounted or may be fixed to or integral with the dies. The tape beads are accommodated in channels 15 in the dies. The plastic material is injected through gate 7, sprue 8 and runners 9 into the mould cavities 5, 6.