GB729960A - Power operated torque-applying tools, such as socket wrenches - Google Patents

Abstract

729,960. Screwing-up and unscrewing bolts etc.; tapping. HAUTAU, L. A., and HAUTAU, C. F. Dec. 30, 1952, No. 33015/52. Class 83 (3). In a machine for screwing-up fasteners, such as bolts 87, or for tapping, the wrench 100 is rotated by a hydraulic motor 28 through gearing 50, 51 and is fed axially by a hydraulic motor 28 through gearing 50, 51 and is fed axially by a hydraulic or pneumatic jack 30, the speed and torque of the motor at various stages being controlled by means including relays, contactors and solenoids and also an adjustable spring-loaded feeler rod 84 which extends through the wrench socket 29 so that it can engage the head of the bolt 87. A pump 20 supplies the motor 28 and, at the beginning of the operation, a solenoid 34 sets a valve in the pump so that the supply passes through a flow-control valve 23 to rotate the motor at low speed and torque while a solenoidoperated valve 33 is set to supply air to the jack 30 to hold the wrench in the retracted position. The operator then closes a switch to set the valve 33 so that the wrench is lowered to engage the socket with the bolt head and start the bolt on the threads. When the socket has engaged the bolt head by a small amount, movement of the feeler rod is arrested by the bolt head while the wrench continues to move until, after a predetermined movement, the roller 74 of a switch 55 carried by the wrench disengages from an arm 73 on the feeler rod. The switch 55 then closes and energizes a solenoid 37 that opens a valve 25 so that an increased flow of fluid is supplied to the motor through a by-pass line 26 and flow-control valve 24, thus rotating the wrench at high speed and low torque. At a predetermined position in the downward movement of the wrench, the undersurface of a collar 104 carried by it contacts the roller 106 of a switch 56 on the stationary wrench-housing to energize the solenoid 34, so that the pump operates at high pressure, and de-energize the solenoid 37 so that the fluid flow is reduced, the wrench thus being driven at low speed and high torque forthe final tightening of the bolt. When, owing to increase, resistance to turning of the bolt, the pressure in the supply line 22 to the motor rises, a pressure valve 27 closes a valve 27a (not shown), but the wrench continues to rotate until one of several buttons 105 on the collar 104 contacts the roller 107 of a switch 58 in series with the switch 27a. The closure of the two switches 27a and 58 de-energizes the solenoid 34 so that the pump again supplies at low pressure with the result that the motor stalls,. the wrench stopping at the required position since the number of buttons 105 corresponds to the number of faces on the bolt head. The wrench housing is adjustable on a pillar 14 and the downward movement of the wrench is limited by the abutment of an adjustable nut 98 with a rubber cushion 61 on the upper end of the gear shaft 60. It is stated that the machine may be used for unscrewing or for tapping.