Patent ID: 7789602

Claim:
A motor element comprising: an elongated shank; a drive shaft rotatably mounted in the elongated shank; a longitundinally-extending rod mounted in the drive shaft and coaxially displaceable within the drive shaft, the longitudinally-extending rod having an open front end proximate a front end region of the elongated shank, and a rear end; a tool-holder, at least one end of the tool-holder being disposed within the open front end of the longitudinally-extending rod; a disconnectable coupling disposed between the longitudinally-extending rod and the tool-holder; a locking element for the coupling that prevents the coupling from disconnecting the tool-holder from the longitudinally-extending rod when a tool is inserted into the tool-holder; an actuating sleeve mounted in an annular groove in the elongated shank and located near the rear end of the longitudinally-extending rod; and an axially movable pressure element located aft of the rear end of the longitudinally-extending rod, the axially movable pressure element being connected to the actuating sleeve, wherein locking/unlocking of the tool-holder and the longitudinally-extending rod is effected by a relative movement between the tool-holder and the tool, and wherein rotation of the actuating sleeve moves the pressure element forward, toward the rear end of the longitudinally-extending rod, thereby moving the longitudinally-extending rod forward, unlocking the coupling.