Patent GB-971800-A (GB)
Title: Controllable-torque drive arrangements
IPC: B25B23/145
Filed: 1962-12-12
Abstract: 971,800. Positive clutches; slip couplings. MASTER POWER CORPORATION. Dec. 12, 1962 [Dec. 14, 1961], No. 46946/62. Heading F2C. [Also in Division B3] A pneumatic impact wrench 10, Fig. 61, comprises a motor housing 11, a clutch housing 13, valve means 14 in a handle 12, an output spindle 15, and torque control means 16. A driving member 17, Figs. 1, 13, is coupled to a driven member 18, by helical splines 20, 21, member 17 having teeth 17a for co-operation with an impact clutch. A member 27 is rotatably mounted on member 17 by balls 28, Figs. 1, 3, and is keyed to a sleeve 31 by a pin 32. Sleeve 31 is rotatably mounted on driven member 18, by balls 35, and a hollow body 38 is screwed to member 27, so that the tension in Belleville washers 42 can be adjusted, to exert a force to move members 17, 18 into engagement, to maintain an air sealing engagement of faces 25, 26. Air is supplied to faces 25, 26, from valve means 14, through an auxiliary air circuit formed by conduits 58, 57, 56, 55, 49, 45, and also to the motor through conduit 77. Valve means 14, Figs. 1, 16, comprises a bush 61, a secondary valve 66, slidable in the bush, and a primary valve 68, slidable in valve 66. Body 38, Fig. 6, is adjustable on sleeve 31, to vary the torque setting, by a worm 95 on a key 94, which is passed through an aperture 92 or 93, and co-operates with splines 96 on the sleeve. A locking collar 97 is slidably keyed and splined on body 38, and is removed prior to adjusting the torque setting, by depressing a detent 100. Sleeve 31 is graduated on its forward face, which co-operates with a line on collar 97, to indicate the torque setting. In operation, air is supplied to bush 65, Fig. 16, primary valve 68 is seated on valve seat 71, air passes through bore 72 into chamber 73, to move secondary valve 66 off its seat 78, and to pressurize the auxiliary air circuit. Trigger 91, Fig. 1, is depressed, rod 83, Fig. 16, moves down, and rubber plug 90 closes bore 72 of primary valve 68, thus isolating the auxiliary air circuit which is still pressurized. Trigger 91 is further depressed, and valve 68 moves away from seat 71, air passes through ports 75 in valve 66, and ports 76, to conduit 77, and thence to the motor, which then drives the wrench. When the predetermined torque is reached, members 17, 18 move axially relative to each other on splines 20, 21, to overcome washers 42, and faces 25, 26 are separated to allow the air to escape. Valve 66 is seated at 78, and the motor stops. In a modification, Figs. 25, 26, 28, a nut runner 112 has an in-line handle 113, and an angled head 119, the drive being supplied through shaft 124, and bevel gears 126, 127. Air is supplied from valve means 14<SP>1</SP> to conduits 152, 153, 49<SP>1</SP>, 156, 156a, 157, 158, 159, 163, and thence to seal faces 136, 137, and also through conduit 77<SP>1</SP> to the motor. The torque setting is adjusted by holding nut 140 stationary, and rotating head 119, thus screwing the nut on shaft 124, and compressing or expanding washers 42<SP>1</SP>. In a further modification, the coupling means between the driving and driven members may comprise a ball and cams 165-167, Fig. 33, instead of helical splines or bevel gears. U.S.A. Specifications 3,001,428 and 3,001,429 are referred to.