Abstract: A tool mounting between a cutting tool, for example a drill, and a machine spindle, comprising a tool element and a tightening device. The tool element consists of a body and an expandable attachment tap. The attachment tap is formed with grooves to receive a gripping implement of a tool interchanging mechanism and with a through opening to receive an end portion of a pull rod. The tightening device comprises a pull rod movably mounted in an inner pipe and forwardly projecting resilient portions. During changing to an other tool the opening at the attachment tap (13) is moved over the end portion by means of the gripping implement while a wall of the opening of the attachment tap slip against the resilient portions until a stop pin on the tool shank engages the end surface of the end portion and the resilient portions snap into recesses in the hole wall.

Abstract: A throttle actuating mechanism is employed in conjunction with a chain saw which has a trigger and is mounted for pivotal movement about a rotary axis from a rest position toward a workpiece. The mechanism includes a lever pivoted coaxially with the rotary axis of the chain saw and carrying an adjustable pin. The pin is engaged by the chain saw trigger when the chain saw is pivoted toward the workpiece, whereby the lever pivots in a first direction along with the lever. A spring yieldably opposes pivotal movement of the lever in the first direction, thereby causing the pin to actuate the trigger when the chain saw leaves its rest position. The lever engages a stop while pivoting in the opposite direction and before the chain saw reaches its rest position, whereby the trigger is deactivated when the chain saw is in its rest position.

Abstract: A tool shaft is detachably fastened in a tool holder by means of a plurality of gaskets which are each sandwiched between a pair of press rings. The tool shaft extends through the press rings and gaskets. A screw is provided for compressing the gaskets between the press rings. The gaskets are disposed in recesses of larger volume. The gaskets are nonsymmetrical about the longitudinal axis of the tool shaft. When compressed, the gaskets force the tool shaft laterally against the rings to prevent radial misalignment of the tool shaft.