Abstract: A carriage drive system for a metal working machine wherein the carriage supports the metal working tool. The carriage drive comprises a worm gear rotatably engaged with a rack arrangement, driven by a motor and gear box on the carriage. The rack arrangement comprises a pair of rack sections opposed to one another along the sides of the worm gear. The carriage drive is pivotably supported on the carriage by a pivot pin which permits slight rocking and self centering motion in the carriage drive as it propels the carriage on its ways.

Abstract: A valve operator utilizes a disconnectable worm gear arrangement to drive a valve spindle. An hand crank may be used to disengage the power-driven worm gear arrangement and to manually drive the valve spindle, if necessary, by pivoting a bracket holding the end of the worm shaft. The worm gear is self-locking so that reaction forces from the valve cannot move the worm gear. A torque-sensing lever, responsive to axial movement of a highly torqued drive shaft, pivots against the force of a biasing spring to operate a microswitch to cut off electrical power to the drive motor for the valve operator should the torque exceed a predetermined amount. Additional protection against torque overload is provided by an adjustable mechanical clutch which operates in the event of control element failure or misadjustments. One or more microswitches, adjustable in position, are engaged by a traveler which moves along a lead screw driven by a gear arrangement coupled to the valve spindle to control operation of the actuator.

Abstract: A lead screw type control for a miniature worm gear actuated potentiometer having a rotor with a main drive spur gear and a ratcheting drive rack gear. The invention contemplates rack gear teeth formed with a gentle ramp opposed to a more acute ramp such as to resemble a sawtooth configuration in profile. The main drive spur gear is formed on less than the total of the rotor circumference. The ratcheting rack gear is mounted on a portion of the rotor circumference that does not include the spur gear. The main drive spur gear teeth are functional in a plane perpendicular to the plane in which the ratcheting rack gears are effective. Ratcheting is accomplished when the driving lead screw has driven the main-drive spur gear to one of its limits in either a clockwise or counterclockwise direction. At this point, if the same direction of rotation is continued, the ratcheting rack gear is urged into engagement with the driving lead screw by the force of a contact spring.