Patent ID: 7028986

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; and 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 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 open 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 by bolts disposed in apertures in the base ring and threaded into longitudinal openings in a base of the operator housing, wherein the bolts provide substantially the only securement between the operator assembly and the bonnet assembly.