GB705728A - - Google Patents

Abstract

705,728. Making releasable fasteners. LIGHTNING FASTENERS, Ltd. Nov. 28, 1952 [Dec. 4, 1951], No. 28386/51. Classes 83 (2) and 83 (4). [Also in Group XXV] Shearing.-A machine for making top stops and attaching them to stringers of sliding clasp fasteners comprises means adapted intermittently to feed wire or strip material 20 to a shearing position, punch means 6 adapted to reciprocate to cut-off a predetermined length of material,to form the length of material about an anvil 32 to produce a substantially U-shaped element, and then to transfer the element to a clamping position, and means adapted to clamp the element on t6 a stringer tape, the anvil forming part of a pivotally mounted lever 30 and the punch means being adapted to tilt the lever as it transfers the element to the clamping position,. whereby the anvil is removed from the path of the punch means. As shown, a wire 20 is fed by two rollers 21, 22 into a channel 23 and thence across a shearing position in the machine. One of the rollers 22 is indirectly driven by a ratchet wheel 24 which is moved by a pawl 26 connected by a bell crank lever- 27 and a rod 28 to an adjustable driving plate 29 on a cam shaft 14- which is connected to a driving motor through a one-revolution clutch. Thus for every revolution of the cam-shaft, the wire is advanced a predetermined amount. A length of the wire 20 to form the top stop is sheared by the punch 6 which is reciprocated in a channel by the cam shaft 14. A spring 15 mounted on a peg 16 holds the punch against its cam. After the length of wire has been sheared, further movement of the punch bends the length of wire to the U-shape by engaging it with the anvil 32, FigÀ 5. The anvil 32 is part of the pivoted lever 30 which is urged by a a spring 36 so that normally the anvil is in the path of the punch 6. After the length of wire has been bent to U-shape the anvil is removed from the path of the punch by the engagement of a cam 'block 33 on the punch with a trip portion 34 on the lever. When the punch 6 reaches the top of its travel, the beaded edge of a fastener stringer is inserted in the U-shaped length of wire by hand and two clamping tools are then caused to move transversely to bend the U-shaped length of wire about' the edge of the stringer, The clamping tools are moved by two pivoted levers 17 which are actuated through a sliding wedge member 18, by a cam on the cam-shaft 14. The machine is arranged to stop when the punch is in its highest position so that the stringer tape can be inserted and when it is restarted it then goes-through a cycle of clamping the length of wire to the stringer tape, and shearing and bending the next length under the control of the cam-shaft 14.