Abstract: A valve operator has a de-clutch mechanism for automatically shifting the clutch out of handwheel drive and into electric motor drive upon actuation of the electric motor. The motor drive sleeve 23 has an annular step 25 which has a flat 26. The clutch 50 is biased by spring 55 toward the motor drive sleeve 23 but is prevented from moving in the direction of the motor drive sleeve by the clutch fork 40 which has extending therefrom two latch arms 71,72 one of which 71 is longer than the other 72. The longer latch arm 71 abuts against the step 25 on the motor drive sleeve. When the electric motor M is energized, the motor drive sleeve rotates and the flat 26 comes into alignment first with the longer latch arm 71 and later with the shorter latch arm 72, thereby releasing in two steps the clutch fork 40 and allowing the clutch 50 to shift out of handwheel drive and into electric motor drive.

Abstract: A portable drive unit for a valve actuator includes a portable two-cycle or four-cycle gasoline engine and a gear reducer. The gasoline engine is bolted, through vibration damper means, to the housing or gear box of the gear reducer. The gear box is clamped to the valve actuator through an annular clamp and clamp-receiving adapter structure which also includes vibration damper means. A flexible sleeve coupling in the bore of the annular clamp and clamp-receiving adapter couples the output shaft of the gear reducer to the handwheel input shaft of the valve actuator.

Abstract: A de-clutch mechanism is actuated, when the power is off, by manual actuation of a de-clutch lever shaft. When thus actuated, the de-clutch mechanism couples a rotatable driven sleeve to a handwheel drive and decouples the sleeve from the power drive. When the power is activated, the de-clutch mechanism automatically disconnects the handwheel drive. A typical application of the de-clutch mechanism is in valve operators.