Patent GB-917545-A (GB)
Title: Master and slave manipulators
Inventor: OPPENHEIMER PAUL
IPC: B25J3/04
Filed: 1960-03-15
Abstract: 917,545. Master and slave manipulators. LUCAS (INDUSTRIES) Ltd., JOSEPH. March 13, 1961 [March 15, 1960], No. 9058/60. Class 39 (4). A manipulator comprises a handle end having a pivoted arm 5 coupled by a pin-and-slot arrangement 8, 7 to the piston rod 9 of a master cylinder 10, the cylinder 10 being connected to a slave cylinder 13 through an hydraulic circuit including servo mechanism 30, Fig. 2. The slave piston controls a toothed rack 14 operating toothed segments 15, 16 connected to arms 17, 18 pivoted to jaws 19, 20. The arms 17, 18 and links 21, 22 maintain the jaw faces parallel to each other and springs 24, 25 return the jaws to their open position. The handle and jaws are carried at opposite ends of a rod 61 universally mounted in a support 62. The servo mechanism 30, which ensures that a magnified pressure is exerted by the slave piston relative to the pressure applied to the master piston, comprises a body 31 having a stepped piston 33 biased by a spring 34 in a stepped bore 32, the larger end of the bore being connected through an inlet 35 to the master cylinder 10. The smaller end of the bore 32 is connected to a further bore 36 having an outlet 37 connected to the slave cylinder 13, the bore 36 containing a piston 38 biased by a spring 39. A conical seating in the piston 38 receives the stem 40 of a piston 41 biased by a spring 43 in a cylinder 42 connected at both ends to a valve chamber 44. A T- shaped valve member 45 having a stem engaging a recess 46 in the piston 33 is urged by a bowed spring to close ports 47, 48 but is rockable by the piston so as to uncover either one of them. Port 48 is connected to a compressed air supply. When the master piston is actuated hydraulic fluid is forced past the sealing in piston 38 into the bore 36 and thence to the slave cylinder through outlet 37. The pressure at the inlet 35 is also applied to both ends of the piston 33 which moves to the right owing to the different areas of its ends whereby valve 45 is rocked to close port 47 and open port 48. Compressed air is thus applied to the left-hand end of cylinder 42 to move piston 41 which in turn moves piston 38 to increase the pressure in bore 36 and hence also in the slave cylinder. The increased pressure also acts on the smaller end of the piston 33 which rocks to close the port 48. Since both ports 47, 48 are closed the system remains in equilibrium. If the pressure in the master cylinder is increased the mechanism acts to admit more compressed air through the port 48 which opens and the pressure in the slave cylinder is increased. If the master cylinder pressure is reduced the valve 45 rocks to open the 47 and connect the left-hand end of the cylinder 42 to atmosphere through exhaust passage 49. Stop cocks 11, 12, 28, 29 permit the mechanism 30 to be cut out and a direct connection to be established between the cylinders 10, 13. In a modification (Fig. 3, not shown), a further servo mechanism is provided to control opening of the jaws and the springs 24, 25 may be omitted. The Provisional Specification refers to Specification 786,524.