Abstract: A hydro-impulse screwing device comprises a rotary drive motor, a power source for the motor, a drive shaft, a pulsating hydraulic drive connecting the motor to the shaft and a power cut-off for the motor. The load at which the power cut-off functions is adjustable. The tool has a borehole extending through the length of the shaft, a conduit for conducting hydraulic fluid from the drive to the borehole, a valve in the borehole movable from a closed position to an open position in response to hydraulic pressure corresponding to a predetermined load to allow hydraulic pressure from the drive to actuate the power cut-off, a biassing element in the borehole for biassing the valve toward a closed position against the hydraulic pressure, wherein the force of the biassing element is adjusted at the end of the drive shaft to change the load at which the power cut-off operates.

Abstract: This invention relates to a rotary impulse screwing device which generates only one pulse per rotation of the output shaft. Two main and two additional lamellas are adjustably positioned in the output shaft. The two main lamellas seal at a minimum of two times per rotation of the output shaft. The two additional lamellas are adjusted independently via separate recess tracks to ensure that each additional lamella seals at only one point per rotation of the output shaft. The independently articulated additional lamellas further ensure that the load on the output shaft bearing is symmetrical on non-impulse points of rotation.

Abstract: The power-operated tool, preferably a screw driving implement, includes a switching clutch which transfers the torque from the drive shaft to the output shaft. Upon reaching the given reactive maximum torque, the switching mechanism is activated to turn off the drive. The clutch components are still engaged, so that one torque is transferred to the screw after the unit is turned off. This allows for unsupervised motion upon the output shaft. One should be able to interrupt the torque transfer to the output shaft completely and to return the switching clutch to its original position with certainty and ease. The switching mechanism maintains the valve body of the on-off valve in the open position, with the clutch component of the separating clutch separated by at least one buffer.

Abstract: A power screwdriver or nutsetter has an output shaft provided with a torque measuring transducer and a shaft rotation angle transducer mounted thereon. Tool output torque or final turning of a screw or nut can be measured directly and transmitted to a control unit through a shaft mounted slipring assembly. In one embodiment a bevel gear drive is connected to the output shaft and a force measuring transducer is mounted between the shaft and the tool housing for measuring gear reaction forces corresponding to tool output torque.