| 摘要 |
<p>The present invention provides a motorised valve actuator wherein the drive from the motor (1) to the output shaft (4) of the actuator is via a worm (3) and worm wheel (2) or other gear mesh which is incapable of being back driven, the actuator having an alternative manual drive, the manual drive comprising a hand wheel (37) and a clutch (25) and lever (44) to change from motor power drive to hand drive mode, the actuator further having an intermediate shaft (24) between the motor (1) and output shaft (4), the hand wheel (37) being carried by or at least operatively linked to the intermediate shaft (24) to drive the intermediate shaft (24), the clutch mechanism being associated with/ mounted on the intermediate shaft (24), the intermediate shaft (24) being positioned between the motor (1) and the worm/ worm (3) wheel (2) drive whereby the clutch mechanism associated with/ mounted on the intermediate shaft (24) operates substantially freely when the lever (44) is operated to bring the actuator into hand drive mode, the output shaft torque generated by the previous motor powered run and locked into the output shaft (4) by the non-back driving worm (3) /worm (2) wheel mesh not being locked into the clutch mechanism.</p> |
