GB774894A - Improvements in, or relating to, machine presses - Google Patents

Abstract

774,894. Punching; making toothed gearing. BIRMINGHAM STOPPER & CYCLE COMPONENTS CO., Ltd. Aug. 17, 1954 [May 22, 1953], No. 14424/53. Classes 83 (2) and 83 (4). A detachable work - holding and indexing device for adapting a punching press to punch notches in a circular blank, e.g. to form the teeth of a bicycle chain wheel, comprises a carrier secured within the frame of the press below the working bed, a shaft journalled in the carrier, passing through the working bed and supporting at its upper end a work-holder,- and fluid-pressure operated mechanism for rotating the workholder step-by-step in time with the movement of the press ram. A cam 38 secured on the crank-shaft 4 of the press actuates a valve 35 controlling the supply of oil to a cylinder 34. During the upward stroke of the punch 3, the piston in the cylinder 34 is returned by springs 32 to cause a pawl 42 to step a toothed wheel 10 on the shaft 6 carrying the work-holder 9. The power stroke of the piston actuates a finger 30 which locks the toothed wheel 10 while each notch is punched. The press is started by a pedal-operated clutch, and when the shaft 6 has turned through a complete revolution a projection thereon operates a valve 47 which disengages the clutch to stop the press. The gearblank is clamped on the work-holder 9 by a rotatable disc 15 supported on arms 16 pivotally mounted on the working bed 1. A handle 24 supported on the bed 1 operates a crank to raise or lower the clamping disc 15. A rod 48 connected to the arms 16 prevents engagement of the clutch when the clamping disc 15 is raised. The exhaust oil from the cylinder 34 is sprayed on to the tool to act as a lubricant.