Abstract: 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 the 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 of the passage of electric current from a battery 61 to an electric control circuit 6.

Abstract: Disclosed is a tightening control apparatus for a torque wrench including a pressure detecting device for detecting an admission pressure supplied to a torque wrench. A pressure change detecting device determines a change in pressure detected by the pressure detecting device. A striking signal output device outputs a striking signal when the change reaches a reference value.

Abstract: This invention discloses a pneumatic cutter for concrete and the like in which: a suction pipe is provided on a circular arc-shaped case covering the upper half of a disk cutter member driven by air motor incorporated in a body, and a venturi section and an exhaust cylinder are provided in connection to the suction pipe in a row; a valve and a branched pipe are provided in connection to an air hose coupling cylinder in order, and in which a larger pipe of the branched pipe is connected to the air motor while a smaller pipe is connected to the venturi section; and an exhaust port of the air motor is provided on the body, and an exhaust nozzle which is provided on a surface where the circular arc-shaped case faces to the disk cutter member and the exhaust nozzle are connected to each other through a communicating passage.

Abstract: A communication passageway is formed to extend from the end surface of a cover member opposed to the axial end surface of the shoulder portion of a main shaft and through the main shaft so that in only one of the two particular phase conditions obtained per revolution of an oil cylinder, it establishes the communication between high and low pressure chambers to thereby equalize their pressures.The communication passageway establishes the communication between high and low pressure chambers in only one of the two particular phase conditions obtained per revolution of the oil cylinder and makes it possible to produce percussion torque in the other particular phase condition.

Abstract: A grinding and polishing apparatus wherein an air grinder is incorporated in the tool attaching spindle of a machining center main body in exactly the same manner as in the other exchange tools so that grinding and polishing operations can be performed. The tool attaching spindle is centrally formed with a tool mounting bore and a compressed air feed passage. The air grinder is attached to the tool mounting bore and driven by fluid being fed from the compressed air feed passage. The apparatus further includes air feed control means, whereby supply of fluid to the compressed air feed passage is started after the base portion of the air grinder is mounted in the tool mounting bore and supply of fluid is stopped immediately before the air grinder is removed from the tool mounting bore.

Abstract: An air motor includes an arrangement such that a part of an exhaust air from a cylinder of the air motor passes through a gear chamber containing a gear mechanism which links a gear fixed to a shaft directly connected to a rotor with a power output shaft and is discharged through a silencer.