Actuator and latch

Claim 1

A shock-absorbing actuator apparatus comprising: an actuator body having a central longitudinal chamber formed therein; a hollow piston rod disposed within the central chamber of the actuator body and slidably movable longitudinally therein, the piston rod at a first end thereof extending externally of the actuator body and being connected to an object which is to be displaced on operation of the actuator apparatus; an actuator piston disposed within the central chamber of the actuator body and having a centrally disposed longitudinal aperture therein, a second end of the piston rod being fixedly received within a first end of the aperture, the piston having a reduced forward end portion defining a shoulder and a tapered forward end defining a camming surface; striker means carried by the actuator piston at a second end thereof opposite said first end; a buffer rod disposed within the central chamber of the actuator body, a first end of the buffer rod extending through the aperture in the actuator piston at a second end of the actuator piston and being extendible into the hollow piston rod on movement of said piston roD toward the buffer rod; latch means having a bolt engageable with the shoulder on the actuator piston, said bolt being displaceable from the shoulder by a fluid under pressure to permit movement of the actuator piston in the actuator body, the fluid acting also to displace the actuator piston; buffer means for cushioning movement of the actuator piston on movement thereof toward the second end of the actuator body, said buffer means including a primary buffer and a secondary buffer, the primary buffer comprising, a buffer piston rod connected to the aforementioned buffer rod and axially aligned therewith, a driven element on the buffer piston rod, a driving element mounted for limited sliding movement on the buffer rod and on the buffer piston rod, and spring means between the driving element and the driven element; and means for introducing fluid under pressure into the actuator body to operate the latch means and to displace the actuator piston within the actuator body.