摘要 |
The present invention provides an improved two-stage actuator (20)' that broadly includes: a first cylinder (21 )°; an intensifier piston (22) mounted in the first cylinder for sealed sliding movement therealong,- the intensifier piston having a large-area surface (26, Al) exposed to ambient pressure, and having a small-area surface (30, A2); a second cylinder (23) having an end wall (36); an actuator piston (24) mounted in the second cylinder for sealed sliding movement therealong; an actuator rod (39) connected to the actuator piston for movement therewith and having an intermediate portion sealingly penetrating the second cylinder end wall; the actuator piston having a large-area surface (27, A3) and a small-area surface (37, A4),- an intermediate chamber (35) communicating the intensifier piston small-area surface with the actuator piston large-area surface; and an incompressible fluid in the chamber; whereby ambient pressure (i.e., the pressure of sea water at the depth at which the device is submerged) will create pressure in the intermediate chamber for urging the actuator pis ton to move toward the second cylinder end wall. |