GB561980A - Improvements relating to draw bench dogs - Google Patents

Abstract

561,980. Drawing tongs and grippers. T.I. (GROUP SERVICES), Ltd., and HACKETT, G. Dec. 8, 1942, No. 17455. [Class 83 (iv)] A draw bench hook c and carriage a has wedge grippers f for the work slidably mounted on the carriage and rotated at i for activation by a lever h pivoted on the carriage and fitted with a spring h<1> that tends to move the wedges to the open position. Levers are pivoted one on each side of the carriage and connected by a pin and roller j<1> that actuates the lever h to close the wedge jaws. The levers j are also connected to the carriage at their other ends through toggles m and to each other by a weight l. At the end of the return stroke of the carriage, an adjustable stop p breaks the toggle and the lever j acts to close the jaws f on the work. At the same time a spring controlled rod s trips a pivoted latch q allowing the hook c to drop and engage the chain d. As the hook takes up the pull; the chain lifts and the hook re-engages the catch at r, and at the end of the draw a fixed cam engages the roller n and straightens the toggle releasing the grip of the jaws f on the work. The chain then being freed from pull falls away from the hook. The lever j may be replaced by a member slidable on the carriage, or the catch may be tripped by a cross-bar t carried by the levers j. When a rope is employed to return the carriage it is attached to the junction of the toggle links, and on impact of this with the stop p a slight further movement of the carriage operates the toggle, the fixed cam being dispensed with.