摘要 |
A motorized control for driving a rotatable shaft-actuated device, such as a valve, comprising a base plate, a top housing, a work plate intermediate the base plate and the top housing and a plurality of stiff legs extending between the base plate and the housing, wherein drive motors are mounted on the work plate to drive a drive shaft that is attached to the shaft-actuated device. The improvement provides elastomeric bias means that remain at rest during normal operation of the control, and deform, to store energy, at the end of control travel, to be released at the begining of travel in the opposite direction, to aid the controller to break loose any binding in the valve.
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