GB957805A - Improvements in or relating to the working of metals - Google Patents

Abstract

957,805. Making crank-shafts; rolling. BIRMINGHAM SMALL ARMS CO. Ltd. Oct. 11, 1962 [July 12, 1961], No. 25178/61. Headings B3A and B3M. A method of rolling the fillets of the crankpins and journals of a crank-shaft comprises rolling all the fillets except those of one or two journals, measuring the amplitude of eccentricity of the or each remaining journal, and then rolling the or each remaining journal to cause opposite distortion of the crank-shaft to reduce the eccentricity to an acceptable value. Rolling of the fillets leads to burnishing, which improves the physical properties and fatigue resistance of the fillets. Control of the rolling may be hydraulic pneumatic or electric. As shown, clamps 6 carrying hydraulically actuated rollers are arranged on the crank-pins and journals of the crank-shaft 1, cylinders 7 determining the pressure on the rollers. The crank-shaft is driven through gearing 4 by a motor 5, and an indexing drum D driven by the same motor through gearing G actuates valves 8-11 to control the rolling sequence. These valves direct fluid at either high or low pressure from reducing valves VH and VL to the cylinders 7. For rolling the final journal, signals from a transducer 26 and a reference pick up 27 are fed to a computer 28 to control, via a valve 29, the rolling pressure in a cylinder 34. The cylinder 34, Figs. 3 and 4, controls the pressure between rolls 39 and inclined rolls 38 through levers 31 and 32, the rolls 38 being supported by a profiled back-up roll 37. Specifications 943,255, 957,711 and 957,712 are referred to.