Abstract: This invention relates to a driving device (1) comprising a drive shaft (3) that is rotatably supported in a housing, which driving device includes a position indicator for said drive shaft, wherein a cam (27) is present on the drive shaft, whose cam surface mates with one end of a feeler pin (29) which extends perpendicularly to the drive shaft, and which end is pressed against said cam surface under spring pressure (37), all this in such manner that movement of the feeler pin in its longitudinal direction, which is effected by the cam surface upon rotation of the drive shaft, provides an indication as regards the angular displacement of the drive shaft.

Abstract: This invention relates to a driving device (1) comprising a drive shaft (3) that is rotatably supported in a housing, which driving device includes a position indicator for said drive shaft, wherein a cam (27) is present on the drive shaft, whose cam surface mates with one end of a feeler pin (29) which extends perpendicularly to the drive shaft, and which end is pressed against said cam surface under spring pressure (37), all this in such manner that movement of the feeler pin in its longitudinal direction, which is effected by the cam surface upon rotation of the drive shaft, provides an indication as regards the angular displacement of the drive shaft.

Abstract: An electro-mechanical actuator for operating a fluid control valve and controlling the operation of one or more field instruments, including other valve actuators. An electro-mechanical actuator has a drive unit and an electric motor driving the drive unit to open and close a fluid control valve to the fully opened and fully closed states under the control of monitoring limit open and limit closed sensors. Auxiliary control output lines connected to other field instruments from the electro-mechanical actuator drive associated fluid control valves to fully open and fully closed states. Limit open sensors and limit closed sensors monitor the valve open and closed state of the other respective field instruments and through a respective pair of auxiliary travel input lines to the electro-mechanical control the field instrument.

Abstract: A fluid motor actuator of the type in which an actuator member is moved in either one of two opposite directions from a rest position to an actuated position includes a fail-safe mechanism having compression springs coupled with the actuator member for compression of the compression springs in response to actuation of the actuator member in either of the two opposite directions for establishing a restoring force which, upon loss of motive power, will return the actuator member to the rest position and maintain the actuator member in the rest position pending restoration of motive power.