Abstract: A pulse tool, especially a nutsetter, comprises a pulse unit including a hydraulic cylinder driven by a motor, and a driven shaft supported in the hydraulic cylinder. Two seal rollers are supported in radial grooves of the driven shaft. The rollers are power-operated towards the inner wall of the cylinder. The seal rollers are simultaneously in contact only in a single rotary position of the cylinder with seal strips that project relative to the inner wall of the cylinder so as to produce an angular momentum. To simplify the structure of the pulse tool and to extend the period of use at the same time, the radial groove which receives the seal roller serving as a compensating roller comprises a lift delaying device for the limited centrifugal movement of the compensating roller.

Abstract: The invention is directed to a method for tightening threaded fasteners by means of a controlled fastener-driving tool. The tightening of the fasteners is controlled by the elastic limit thereof. The slope of the actual load-strain characteristic curve is continuously determined during the fastener-driving operation. This actual slope is compared with a predetermined slope determined with reference to a characteristic curve. When the predetermined slope is reached, a control signal is generated to switch off the fastener-driving tool. In practice, departures occur in the actual characteristic curve of an actual fastener-driving operation.

Abstract: 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.

Abstract: An artificial hinge pin having a self-cutting threaded portion is inserted into a prepared bone with reduced reaction moment by a hand-held power tool which imposes a rotary oscillating movement on the pin during the insertion process. The tool has an output shaft driven by an overriding ratchet type coupling providing repeated impacts to the output shaft. A plurality of elastic rods connected to the output shaft are arranged coaxially around the shaft and are anchored to a rotary brake disk. Braking force on the disk is controlled by an adjustable compression spring. The eigenfrequency of the elastic system comprising the rods and output shaft may be adjusted to the impact frequency of the ratchet coupling.