Patent ID: 8464799

Claim:
A surface controlled subsurface control valve for operating in a wellbore extending through a subterranean formation, the valve comprising: a valve body defining a bore for fluid to flow through; a bore closure assembly movable between an open position in which the bore closure assembly allows fluid flow through the bore and a closed position in which the bore closure assembly prevents fluid flow through the bore; a mechanical linkage operatively coupled to the bore closure assembly; a rotary motor operatively coupled to the mechanical linkage; and a primary control assembly configured to vary the force applied to the bore closure assembly by the rotary motor, such that: during a first portion of movement of the bore closure assembly in a first direction, the rotary motor applies a first amount of force to the bore closure assembly, the first amount of force based on a first present operating condition; and during a subsequent portion of movement of the bore closure assembly in the first direction, the rotary motor applies a second amount of force to the closure assembly, the second amount of force different than the first amount of force and applied by the rotary motor in the same direction as the first force and during movement of the bore closure assembly in the first direction, the second amount of force based on a second present operating condition.