Locking piston assembly

A locking, piston assembly (100) including a piston chamber (107), a piston rod (106) configured to be substantially extended from and substantially retracted into the piston chamber (107), and a piston head (108) coupled to the piston rod (106) and configured to move reciprocally in the piston chamber (107), with the locking piston assembly (100) being characterized by:

• at least one latch ring (130) extending from the piston head (108);
• and
• at least one lock (120) configured to engage the at least one latch ring (130) in order to mechanically lock the piston head (108) and the piston rod (106) in at least a substantially fully extended position in an absence of a pressurized fluid in the lock (120) and configured to disengage the at least one latch ring (130) in order to unlock the piston head (108) and the piston rod (106) upon introduction of the pressurized fluid that is provided to retract the piston rod (106), with the at least one lock (120) comprising;
• a biasing member(122);
• a locking member (124);
• a locking member upper seal (125) configured to continuously seal the locking member (124) to a lock bore(128) configured to receive the locking member (124);
• and
• a locking member lower seal (126) on red to block and unblock a piston chamber port (153) extending between the lock bore (128) and a piston chamber (107), with an upper seal cross-sectional area being greater than a lower seal cross-sectional area, wherein the lower seal cross-sectional area requires a first pressure to move the locking member (124) to an open position and the upper seal cross-sectional area requires a second pressure to keep the locking member (124) at the open position, and wherein the first pressure is greater than the second pressure;
• wherein the locking member (124) and the locking member lower seal (126) block the piston chamber port (153) when in a lock position and unblock the piston chamber port (153) when in an unlock position and wherein the pressurized fluid is introduced into the Mon chamber (107) and the piston rod (106) is retracted only after the at least one lock (120) is unlocked.