Patent ID: 6854704

Claim:
A valve actuator for moving a valve gate between open and closed valve positions within a valve body, the valve actuator comprising: an operator assembly comprising: an operator housing defining a pressure chamber therein and having a fluid entry port; an operator member within the operator housing movable toward the valve body in response to pressurized fluid introduced into the operator housing pressure chamber through the fluid entry port; and a shaft extending from a shaft aperture in the operator housing, the shaft axially movable through the shaft aperture, sealingly rotatable with respect to the operator housing, and rotatable with respect to the operator member, and a bonnet assembly comprising: a bonnet housing securable to the valve body, the bonnet housing having a bonnet housing bore therethrough; an elongated bonnet stem having first and second ends, the stem axially movable in the bonnet housing bore, unconnected at the first end to the operator member, and securable at the second end to the valve gate for moving the valve gate to the top and closed valve positions; a spring for producing a biasing force opposing axial movement of the operator member toward the valve body; a contact member, separate from the operator member, having an outer flange, and rotatably and axially affixed to the first end of the bonnet stem, and having a surface facing the operator member for drive contact with the operator member; an upper spring retainer having an inner flange for engagement with the outer flange to transmit the biasing force to the bonnet stem and to receive the movement of the operator member toward the valve body; and a base ring coaxially surrounding the bonnet housing, the base ring securing the operator housing to the bonnet housing.