ES342387A1 - Improvements in or relating to Apparatus for Forging Crankshafts and like Forgings. - Google Patents

Abstract

In a crankshaft forging apparatus having a pair of slidable cradles 14, 14a movable towards each other for upsetting therebetween a workpiece 21, and a transversely movable anvil 16 for forging the crankpin, the movements of the cradles and anvil are effected by an hydraulic actuator unit B through hydraulic transmission means. Workpiece 21 may be preformed with enlarged portions or these may be produced by the upsetting. Cradles 14, 14a slide on stationary rods 19, 19a having stationary pistons 20, 20a working in moving cylinders 13, 13a. These are supplied with hydraulic fluid from actuator cylinders 11, 11a which may be interconnected to ensure uniform movements of the cradles. The inner forging surfaces of the cradles may have die portions for shaping the crank webs. The crank pin is formed by a forked anvil 16 consisting of two halves (16), (16a), Fig. 7 (not shown), pivoted at 29 to a vertical slide (30) actuated by a pair of pistons 15 supplied with hydraulic fluid from actuator cylinder 12. The two fork halves (16), (16a) are pivoted by hydraulic cylinders (28) and locked in their closed position by a clamp (31) actuated by an hydraulic cylinder (33). The cradles 14, 14a have pivoted caps (25), Fig. 5 (not shown), actuated by hydraulic cylinders (26). The actuator unit B may be operated by the ram 17 of a press and the hydraulic system provides a force multiplication of at least 2: 1. The actuator cylinders 11, 11a, 12 are dimensioned so that the cradles 14, 14a are moved before the anvil 16. Alternatively the actuator units may be operated by an hydraulic pressure generator. An auxiliary pressure generator is used to supply the ancillary cylinders (26), (28), (33) and for retracting the cradles. For determining the angular position of the crank throws, a rotary jig (22), Fig. 6 (not shown), is housed in cradle 14 and rotated by a chain (23) driven by a reduction motor unit (24), or alternatively by a rack transmission driven by a cylinder unit. In another embodiment, Figs. 8-10 (not shown), the cradles are moved by pistons working in single stationary cylinders (35) and are retracted by cylinders (36).