Valve actuator mechanism for lift-turn type valves

A valve actuator mechanism for a lift-turn type plug valve having an internal valve element for movement between an opened and closed position and having a valve stem, which valve element is operated by linear unseating movement, rotational repositioning movement and linear reseating movement, said valve actuator mechanism comprising:

• an actuator housing adapted for fixed assembly with said plug valve;
• a first actuator stem extending from said housing and adapted to be connected in nonrotatable relation and linearly immovable relation with said valve stem;
• a movement translation mechanism within said housing being connected to said first actuator stem;
• a second actuator stem being supported for linear and rotational movement within said actuator housing and defining cam groove means including linear and rotational groove portions, said second actuator stem being in interconnected relation with said movement translation means;
• cam follower means supported by said housing and engaging said cam groove means, said cam follower means and cam groove means moves said valve element in one of said valve element positions, said cam follower means and said cam groove means being cooperative during an operational sequence of said valve actuator to allow predetermined linear travel of said second actuator stem during an initial portion of stem movement in one direction to cause unseating of said valve element, cause 90.degree. rotational movement of said second actuator stem during an intermediate portion of stem movement in said one direction to rotate said valve element and allow predetermined linear travel of said second actuator stem during a terminal portion of stem movement to reseat said valve element;
• and
• a movement translation mechanism incorporating gear means, said gear means translating said operational sequence movement of said second actuator stem, respectively, into an initial linear travel of said first actuator stem in said one direction, an intermediate rotational movement of said first actuator stem and a terminal linear travel of siad first actuator stem in an opposite direction during said one direction of said second actuator stem.