GB1073952A - Improvements relating to drawbenches - Google Patents

Abstract

1,073,952. Drawing. SIR JAMES FARMER NORTON & CO. Ltd. May 8, 1964 [Feb. 14, 1963], No. 5981/63. Heading B3P. A draw carriage includes fluid-operated means for actuating means for gripping a rod or the like to be drawn, fluid-operated means for actuating the chain hook of the carriage, and fluid-operated cushioning means associated with the chain hook to prevent snatch when the hook engages the chain. The carriage comprises a frame 10, runner wheels 11, chain hook 12 and grippers 13. The hook 12 is operated by air cylinders 14 and is connected to the carriage through two cushion cylinders 17. Each gripper 13 is operated by a cylinder 16 to close the jaws on to the work. There are two reservoirs 19 mounted on the carriage and these are re-filled, each time the carriage reaches the die-plate end of the drawbench, by nozzles 18 which engage supply nozzles fixed on the drawbench. A cam on the carriage opens a valve to allow air to reach the supply nozzles. The pneumatic circuit includes sequence valves which ensure that when the start signal is received the gripper cylinders 16 operate first and then the hook cylinders 14 operate. When the hook engages the draw chain the pistons in the cylinders 17 move and compress the air up to a limit set by a relief valve. Air then escapes from the cylinders 17 until the pistons engage the end of the cylinders and the carriage begins to move. A device for preventing damage to workpieces at the end of the draw, particularly slender tubes, comprises an hydraulic cylinder under pressure from a pneumatic dash-pot. The ram of the cylinder is engaged by the leading end of the workpiece when it shoots forward as it leaves the die, and compresses the air in the cylinder against a pre-set relief valve, Fig. 3 (not shown). The Specification states that the whole apparatus could be operated by hydraulic instead of pneumatic means.