GB1498169A - Manipulator - Google Patents

Abstract

1498169 Linkwork SHIROYAMA KOGYO KK 21 June 1976 25751/76 Heading F2K [Also in Division B8] A manipulation arm, used in forge press working or die cast working etc. for gripping and transferring workpieces, comprises two equal length arms 5, 9 the first arm 5 of which is pivotally mounted at one end about the axis of coaxial driving shafts 3a, 4a, on a structure 1, 2 and pivotally connected at its other end via a pin 10 to one end of the second arm 9 the other free end of which pivotally carries via a pin 18 a swivable head 16 having an air suction cap gripper 21. Independent driving motors 3, 4 simultaneously or selectively drive the shafts 3a, 4a, shaft 3a being drivingly keyed fast with the first arm 5 whilst the shaft 4a passes freely through the arm 5 and is drivingly keyed to a first sprocket 6 which is connected via a chain 12 to a second sprocket 11 fast on the pivot pin 10 which is keyed fast to the second arm 9 and freely pivotal in the first arm 5. In addition, connecting rods 8, 15 of equal lengths corresponding to the length of the arms 5, 9 are connected between a fixed pin 7 on the structure 2 via crank hubs 13, 19 pivotally mounted on the pivot pins 10, 18, to a pin 20 on the swivable head 16, the arrangement of the two connecting rods 8, 15 constituting a parallelogram linkage whereby during relative pivotal movement of the arms 5, 9 the head 16 and its associated gripper suction cap 21 are always maintained (i.e. unchanged) at a horizontal orientation. As shown, the sprockets 6, 11 are in the ratio of 2 to 1 to form a straight line motion mechanism, whereby with the motor 3 driving through shaft 3a and the motor 4 inoperative holding sprocket wheel 6 stationary, the arrangement is such that as the arm 5 turns the chain 12 wraps around the larger sprocket 6 to turn the smaller sprocket 11 twice the angular amount in the opposite direction such that the head 16 and gripper 21 move in a straight line motion, i.e. C to B &c. in Fig. 4. If at any position it is required to move the gripper head 16 from the straight line path the second motor 4 may be operated to drive the shaft 4a and via the sprockets 6, 11 and chain 12 turn the second arm 9 from B to A &c. (Fig. 4). By having sprockets 6, 11 of different ratios other than 2 to 1, movement paths of the head 16 and gripper 21 other than straight line motion may be accomplished by operation of the driving motor 3 alone, the second motor 4 always enabling movement of head 16 and grippers 21 from such path simply by operating the second motor 4 either separately from or simultaneously with the motor 3 to additionally drive and turn the second arm relative the first arm via the chain and sprockets 12, 6, 11.