Cooper Industries, Inc.

Deutsche Gardner-denver Gmbh

Eugen Mattheiss

Heinz-Gerhard Anders

Jurgen K Koltermann

Bernhard J Polzer

Dieter W Stein

Konrad Karl Kettner

Dieter Stein

Dieter Weimer

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.

Hydro-impulse screwing device

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. In this way, the drive shaft continues to operate, allowing the clutch component to return to its original position where it engages the other clutch component of the separating clutch, even following interruption of the torque transfer. The power-operated tool may be designed as a hand-operated screw driver or as a multiple screw driver.

Power-operated tool

A power-operated tool is fitted with a drive, whose driving shaft can, by means of a connecting coupling whose actuation depends on the reaction torque, be coupled with a driven shaft. The connecting coupling first interrupts transfer of the torque to the driven shaft, so that, in spite of the running drive, no torque can be transferred to the driving shaft. Immediately afterwards, the drive is disconnected. As a result of this sequence of disconnections, the motor, which continues running, can no longer have any influence on the work in progress so that the fastener being tightened does not reach the point of plastic deformation.

Torque limiting screw-tightening tool

A pneumatic screwdriver or nutsetter includes a manually actuated electrical switch and a solenoid operated motive air shutoff valve which includes a spring biased reset element for moving the shutoff valve closure element from a valve closed position to a valve open position prior to introduction of compressed air to the tool motor. The reset element is retracted away from the closure element by pressurized air upon startup of a tool operating cycle. The closure element is released upon deenergization of the solenoid at a predetermined signal to close the shutoff valve. In an alternate embodiment the switch is replaced by a pneumatic valve and the reset element is pressure air biased to move the shutoff element from the shutoff valve closed position to the open position.

Power tool, in particular a hand-held compressed air screwdriver

A pneumatic screwdriver or nutsetter includes a manually actuated electrical switch and a solenoid operated motive air shutoff valve which includes a spring biased reset element for moving the shutoff valve closure element from a valve closed position to a valve open position prior to introduction of compressed air to the tool motor. The reset element is retracted away from the closure element by pressure air on startup of a tool operating cycle. The closure element is released upon deenergization of the solenoid at a predetermined signal to close the shutoff valve. In an alternate embodiment the switch is replaced by a pneumatic valve and the reset element is pressure air biased to move the shutoff element from the shutoff valve closed position to the open position.

Growing community of inventors

Lauchheim, Germany

Eugen Mattheiss