Drive mechanisms, more particularly for valve actuators

摘要

This invention relates to a motorized actuator in which the motor shaft is drivably connected with the output shaft through an intermediate shaft assembly. The motor shaft assembly includes a worm and wormwheel which is formed with cut-outs each drivably receiving the extended ends of some of the teeth of a pinion which forms part of the intermediate shaft assembly. The pinion is at all times in driving engagement with a gear on the output shaft and is axially movable by a lever to disengage the motor drive so as to allow independent manual operation of the pinion and thereby the output shaft by a handwheel mounted on a shaft. The shaft is drivably coupled with a wormwheel which is in driving engagement with the pinion by means of the driving lugs.