Patent GB-548819-A (GB)
Abstract: 548,819. Sliding clasp fasteners. WAHL BROS., Inc., and WATKINS, A. H. March 5, 1940, No. 14924/41. Divided out of 547,663. [Class 44] Sliding clasp fasteners have the inter-engaging elements in the form of spiral coils or separate loops made from flat material of uniform crosssection throughout their length, without the usual projections and recesses. The coils and loops are preferably elongated in a direction parallel to the stringer tapes and this elongation may be effected by flattening after the coils have been interengaged. The coils interengage over the major portion of their length in the direction of elongation and the distance between adjacent turns of the coils, or adjacent loops. is less than the width of the strip composing the coil or loops. Fig. ,1 shows a few interlocking turns of coils 11, 12 near the ends of separable tapes 13, the terminal coils 23, 24 on to which the slider rides at the end of the opening movement being short so that they do not interlock. With the slider, not shown, in this position the tapes can be separated by drawing a male member 25 attached to one tape from the socket member 26 attached to the other tape, and passing said member through the slider. The coils, which are respectively right-handed and left-handed, are secured to meeting edges of the stringers by securing with or without a cord 20 passed through the coil. Alternatively, the turns may be passed between the weft threads of a ladder-like tape formed by omitting warp threads from the central zone of the tape, the tape being then folded upon itself and secured. In a further method the coil is woven in the selvage edge. The coils and loops may, however, be secured in any suitable way as by adhesive. Fig. 8 shows coils 55, 59 attached to adjacent faces along the overlapping edges of materials 56, 60 to be secured. In this case the wider end of the slider is of S-form to embrace the oppositely directed edges. The application to materials overlying, with their edges in register, is also described, in which case the wider end of the slider is of M-form. An alternative form of slider which embraces the coils without embracing the tapes is also described. When the fastener elements are formed as separate loops, these may be produced from the tape material, or from the actual material to be fastened, suitably stiffened if necessary, by slotting to produce a comb-like blank, Fig. 18, the strips 82 having reduced ends 83 which are passed through apertures 84 and bent over, as in Fig. 14. Alternatively, a ladder-like blank may be produced, the continuous marginal strip which replaces the ends 83 being secured to the face of the unslotted portion of the blank. The narrow end of the slider may be flared as at 78, Fig. 11, so that any turns not properly interlocked may be pressed into place by moving the slider back thereover. A double-ended slider 80 may be used if desired, the stringers being interlocked only in the slider. Fig. 11 shows such slider being used to keep coils 55, 59 in correct position during attachment thereto of tapes &c. 75, 76. The tapes are applied between the sliders and pressed into place during passage through the upper slider 74. The sliders may be connected so as to be moved together. Two oppositely directed sliders may also be used to give a limited secured or open portion between the sliders which may be adjusted in position along the stringers. Specification 547,663 is referred to.