GB813687A - Improvements in or relating to torque transmitting device - Google Patents

Abstract

813,687. Screwing-up screws. LIVERMONT, F. W. Oct. 11, 1955 [Oct. 14, 1954], No. 28934/55. Class 83 (3). [Also in Group XXIV] A screwing-up tool comprising an overloadclutch has a tool-holder 14 rotatably supporting collars 23, 24 separated by torque-transmitting balls 29 engaging depressions 27, 28 in the collars. The collars and balls are pressed together by a spring 17. A sleeve 36, splined to the holder 14 by balls 38, has clutch-jaws 44 engageable with clutch-jaws on the collar 23 under the action of a light spring 41. Friction locking-balls 49 in radial holes in the holder 14 engage the bore of the sleeve 36 and a piston 45 located in an axial bore 13 of the holder 14 and acted upon in opposite directions by springs 46, 47. A driving member 10 has clutch-jaws 35 engageable with clutch-jaws 34 on the collar 24 and carries a cylindrical post 12 slidable in the bore 13. In operation, the member 10 is rotated continuously. When the tool 16 is applied to the work the clutch-jaws 34, 35 are engaged and the post 12, acting through the spring 47, moves the piston 45 so that a conical surface 48 thereon moves the locking balls 49 to frictionally grip the bore of the sleeve 36, and the tool 16 is rotated. When a predetermined torque is reached the balls 29 ride out of the depressions 27, 28 and engage in the next pair of depressions. During this movement the collar 23 and sleeve 36 move axially to compress the spring 41. The collar 23 immediately returns to its original position, but the sleeve 36 does not return as it is locked in its forward position by the balls 49. Thus the clutch-jaws 43, 44 are separated and the sleeve 36 and tool-holder 14 stop rotating. When the tool 16 is removed from the work the spring 47 separates the clutch-jaws 34, 35, and allows the piston 45 to release the locking- balls 49 so that the sleeve 36 moves to reengage the clutch-jaws 43, 44 and the tool is ready for use again. In a modification, the sleeve 36 is integral with the collar 23 and has a radial recess to receive a locking-ball to hold the collar 23 disengaged upon excess torque. In another modification the locking-balls 49 are replaced by a leaf-spring locking device. In a further modification the tool is clutched to the collar 24, and the member 14, instead of carrying the tool, is connected to the driving member.