GB1158075A - Power wrench - Google Patents

Abstract

1,158,075. Nut runners. INGERSOLL-RAND CO. 31 July, 1967, No. 35115/67. Heading B3N. [Also in Division F2] A fluid-pressure actuated power wrench comprises a fluid - pressure motor 7, which drives a spindle 10 connected to an output shaft 5 by gears. Motor shaft 8 is connected to shaft 10 by a torque responsive clutch 14 which comprises a helical spring 19 which is expanded out of engagement with a driven member 16 when the torque exceeds a predetermined value, to cause yield of a torque-sensitive coupling between clutch part 15 and shaft 8, the clutch remaining disengaged until the motor is switched off. The sleeve 24 has helical slots 29 housing rollers 30 pivoted on pins mounted in a collar 32 and having a pin 31<SP>1</SP> extending through an axial slot 33 in a stub shaft 27 which is splined to the clutch part 15. The rollers 30 are biased to the rear of the slot by a spring 36 acting through a cup 34. A spring seat 37 for the other end of the spring is held in place by a nut 38 threaded on the sleeve 24 and which can be adjusted by a gear key 42 to vary the torque at which the coupling yields. On yielding, rotary movement of the part 15 relative to the sleeve 24 expands the clutch spring 19 to reduce the clutching engagement, and at the same time a piston rod 59, which is biased into abutting engagement with the pin 31<SP>1</SP>, shifts forwardly to permit a valve element 52 to seat on seat 48, cutting off the air supply to the motor 7, and cutting off the pressure to the forward (left-hand) face of a piston 58, so that the pressure falls, and the pressure on the right-hand face of the piston shifts it forwardly (to the left), and thus shifts the rollers 30 to the end of their slots to complete clutch disengagement and ensure that the clutch remains disengaged until manual actuation of a throttle button 12 cuts off the supply of compressed air to the right-hand face of the piston.