Patent GB-1124030-A (GB)
Title: Improvements in work transfer mechanisms
IPC: B65G25/02
Filed: 1965-12-10
Abstract: 1,124,030. Transferring blanks. B. J. WALLIS. 10 Dec., 1965 [14 Dec., 1964], No. 52688/65. Heading B3W. A work transfer device comprises a carriage mounted for reciprocating movement on a base, a pair of support arms adjacent each of two opposite ends of the carriage, each of said support arms extending laterally from one side of the carriage the outer ends of said arms terminating at the same side of the carriage, a first work engaging member secured to one arm in each pair and a second work engaging member secured to the other arm in each pair, both said work engaging members being disposed laterally on said one side of the carriage and being spaced laterally apart, means for moving the two work engag'ng members towards and away from each other and means for reciprocating the carriage to advance workpieces gripped between the two members. The device, which transfers workpieces through a progressive punching die has a carriage 16 which reciprocates on guide rods 18, 20 mounted on a base 14. A pair of hollow arms 22 project from one side of the carriage and through each slides a rod 24. A bar 26 connects the rods 24 and has workgrippers 28 mounted thereon. Two further rods 32 slide in bushes 30 in the carriage and are connected to a bar 34 which carries workgrippers 36. The ends of the rods are formed with rack-teeth 72 and 76 which mesh with a pinion 74, so that the rods move simultaneously in opposite directions. The rod 32 is pivotally connected to one end of a link 68, the other end of which is journalled on a crank-pin 66 mounted on a pinion 60 which meshes with a rack 58. The rack 58 is formed on an actuating bar 54 which is slidably mounted in the carriage 16 and has a further rack section 52, which meshes with a pinion 50 mounted on a shaft 42. Also mounted on the shaft 42 is a pinion 44 which is rotated by the reciprocation of a rack 46 which has a lost-motion connection with the ram 12 of the press, through the nuts 48. The motion of the work-grippers 28 and 36 is rectangular, as shown by the arrows 80, 144, 146 and 148 on Fig. 1 and to achieve this motion the actuating bar has a lost-motion connection with the carriage 16. Secured to each end of the actuating bar 54 is a bush 90 and mounted on a common pivot screw 82 at each end of the carriage are two latches 84, 86, which are biased by spring plungers to a position eccentric to the bushes 90. In its eccentric position the latch 86 locks the carriage to the base, by moving into engagement with an abutment 118 secured to the base. The latch 86 is disengaged from the abutment by the action of a conical end 96 of the bush which co-operates with a chamfer on one side of the latch. The latch 84 locks the actuating rod to the carriage by engaging behind a shoulder formed by machining a flat 108 on the bush. The latch 84 is disengaged by a heel 130 on the latch engaging a cam 128 secured to the base. As the carriage approaches the left-hand end of its stroke, the left-hand end latch 86 engages the abutment 118 and the right-hand end latch 84 is disengaged from the shoulder on the bush 90, so that the carriage is locked and the bar 54 is released, as the ram reaches the top of its stroke. As the ram descends the actuator bar moves to the right to open the work-grippers 28, 36 and when the left-hand end bush 90 contacts the carriage, this too moves to the right. Safety Device.-The pinion 44 is not mounted directly on the shaft 42 but is secured to a sleeve which has a flange plate connected to it, Fig. 17 (not shown) the flange plate being connected to a collar on the shaft by a shear pin. Two electrical inserts in the collar are bridged by a brass plug in the flange plate. If the shear pin breaks the plug moves away from the contacts and stops the press. Additionally, a second rack 194, which meshes with a pinion fixed on the shaft 42, and the upper end 196 of which is normally just below the under-surface of the ram 12 in its lowest position, is effective to retract the fingers if the shear pin breaks. In a modification, Figs. 19 to 21 (not shown) the pinion (50) is connected to the actuating bar 54(a) through a crank-pin and link mechanism so that the actuating bar has harmonic motion. In this case the rod (32) meshes directly with the pinion 74.