Patent ID: 8141583

Claim:
A controller for controlling a valve actuator, the apparatus comprising: an enclosure; a cylinder, housed within said enclosure, having a vertical length and an internal cavity configured to receive a first end of an actuator shaft, said shaft vertically traversing at least a portion of the vertical length of said cylinder corresponding to an operating stroke of said actuator shaft in response to opening and closing of a valve; a plunger disposed within said cylinder and adapted to engage said first end of said actuator shaft, said plunger traversing a vertical distance within said internal cavity corresponding to the distance traversed by said actuator shaft within said cavity, said plunger engageable within said internal cavity about at least one of a plurality of grooves such that said vertical placement of said plunger within said internal cavity corresponds to the operating stroke of said actuator shaft; wherein said plunger has a generally circular shape having a base and a plurality of teeth extending from said base, each of said teeth extending out from the perimeter of said base wherein each of said teeth are rigidly flexible to provide an outward retaining force from said base.