Autoshut-off device for oil pressure type pulse wrench.

摘要

This invention is intended to effect torque control of high accuracy by detecting the oil pressure at the time of the generation of a pulse which forms the basis of the generated torque for a torque wrench and using the data thus obtained to effect torque control. Oil pressure pulses generated in a pulse generating mechanism (3) by the rotation of an air motor (1) are transmitted to a hydraulic cylinder (4) by a piston (33), a rod (36) and a piston (35). In addition, a pressure sensor (5) installed in the hydraulic cylinder (34) detects the oil pressure pulses and its signal is used to switch a switching valve (7), whereupon a stopping switching valve (9) and a stopping differential pressure valve (8) are successively switched, stopping the feeding of air to the air motor (1) while cutting off the passage of electric current from a battery (61) to an electric control circuit (6). <IMAGE>