US 12,146,589 B2
Actuator assembly for conducting partial stroke testing
Edward G. Holtgraver, Tomball, TX (US)
Filed by QTRCO, Inc., Tomball, TX (US)
Filed on Mar. 15, 2022, as Appl. No. 17/695,020.
Claims priority of provisional application 63/161,579, filed on Mar. 16, 2021.
Prior Publication US 2022/0299132 A1, Sep. 22, 2022
Int. Cl. F16K 37/00 (2006.01); F15B 15/20 (2006.01); F16K 31/122 (2006.01)
CPC F16K 37/0083 (2013.01) [F15B 15/20 (2013.01); F16K 31/1221 (2013.01); F16K 31/1225 (2013.01)] 7 Claims
OG exemplary drawing
 
1. An actuator assembly comprising:
a force module, said force module comprising:
a casing defining a first piston chamber;
a first piston mounted in said first piston chamber for reciprocal movement therein;
a compression spring disposed in said first piston chamber, said compression spring exerting a biasing force on said first piston;
a first piston rod connected to said first piston and having a first free end and a second end connectable to a reciprocally movable shaft;
a first fluid pressure source selectively operable to apply a first force to said first piston in a first direction;
a tandem piston module, said tandem piston module comprising:
a cartridge forming a second piston chamber;
a second piston mounted in said second piston chamber for reciprocal movement therein;
a second piston rod having a first end connected to said second piston and a second free end;
a second fluid pressure source selectively operable to apply a second force to said second piston in an opposite direction to said first direction whereby said biasing force and said second force together exceed said first force.