Abstract: A gear train between an input shaft and an output shaft includes an output gear, through which the output shaft moves axially, and an intermediate gear coaxial with a control shaft carrying an idler gear meshing with a nut threaded on the output shaft. The idler gear is axially movable between a first position in which a first dog clutch connects the idler gear to the intermediate gear so that the nut rotates relative to the output shaft, thereby causing the shaft to be fed to the right, and a second position in which the first dog clutch is disengaged and a second dog clutch connects the idler gear to a fixed member, thereby causing the rotating shaft to be fed to the left. A collar on the shaft acts on a lever which moves the control shaft together with the idler gear from the first position to an intermediate position.

Abstract: A two speed gearbox comprises an input shaft, an output shaft and a reduction gear mechanism, such as an epicyclic gear mechanism, having high speed low torque and low speed high torque output drives. A dog clutch connects the high speed output drive to the output shaft when the clutch is fully engaged. A slidable coupling is rotatable with the low speed output drive and is movable between a first position in which it is disconnected from the output shaft and a second position in which it is connected to the output shaft for driving the latter. A weak spring urges the slidable coupling towards its second position and means, such as a strong compression spring, urges the clutch members of the clutch in to full engagement. A radial flange on the driven clutch member and balls held captive with the slidable coupling interact to maintain the slidable coupling in its first position against the urging force of the weak spring while the clutch members are maintained in full engagement by the compression spring.

Abstract: A control lever for a power tool of a type which is normally held in an operator's hand during use and has a generally cylindrical body and an on/off switch. The switch is operated by an arm of the which is pivotally connected at or adjacent one end to the body. The arm is biased towards a first position in which the switch is `off` and is pivotably movable to a second position in which the switch is `on`. A latch member is mounted for pivotal movement relative to the body and biased by a torsion spring towards a first position in which, when the arm is also in its first position, the latch member engages the arm to prevent unintentional movement of the arm to its second position. The latch member has a thumb engageable section which extends through a slot or aperture in the arm whereby an operator can pivot the latch member towards a second position thus permitting the arm to be moved towards its second position to turn the switch `on`.

Abstract: A power feed rotary tool, such as a drill or a tapper, has an electric motor for rotating the working head and a pneumatic system for advancing the working head. A control rod extends from one end of the tool housing, and is displaced together with the working head, but does not rotate. The control rod controls the feed stroke of the working head. The electric motor is connected to the tool housing between its ends.