Locking cylinder

Claim 1

IN A FLUID-PRESSURE ACTUATOR HAVING A CYLINDER MEMBER AND A PISTON MEMBER RECIPROCABLE AXIALLY THEREIN, MEANS FOR LOCKING THE PISTON AT A LIMIT POSITION IN SAID CYLINDER COMPRISING: A CIRCUMFERENTIAL SET OF DISCRETE LATCH FINGERS OF CURVED TRANSVERSE CROSS-SECTION OF THE SHAPE OF LONGITUDINAL SECTIONS SEVERED FROM A CYLINDRICAL CONFIGURATION BY LONGITUDINAL RADIAL SAW CUTS, SAID CYLINDRICAL CONFIGURATION HAVING A CONCENTRIC, GENERALLY RING-SHAPED ENLARGEMENT AT ONE END AND A FLANGE AT THE OTHER END, THE SECTIONS OF THE ENLARGEMENT CONSTITUTING BEARING PORTIONS OF THE INDIVIDUAL FINGERS AND THE SECTIONS OF THE FLANGE CONSTITUTING LATCH ELEMENTS OF THE INDIVIDUAL FINGERS; MEANS FIXED RELATIVE TO ONE OF SAID CYLINDER MEMBER AND PISTON MEMBER AND FORMING A CIRCUMFERENTIALLY CONTINUOUS GENERALLY RING-SHAPED CAVITY CONFINING AND JOURNALING SAID BEARING PORTIONS OF THE FINGERS FOR SWINGING MOVEMENT OF THE FINGERS; LATCH MEANS FIXED RELATIVE TO THE OTHER OF SAID CYLINDER MEMBER AND PISTON MEMBER TO ENGAGE SAID LATCH ELEMENTS TO RELEASABLY ANCHOR THE PISTON MEMBER AT A LIMIT POSITION RELATIVE TO THE CYLINDER MEMBER, SAID FINGERS BEING BIASED TOWARD THEIR LATCHING POSITIONS; AND LOCKING MEANS TO ENGAGE SAID FINGERS TO POSITIVELY LOCK THE FINGERS AT THEIR LATCHED POSITIONS, SAID LOCKING MEANS BEING RELEASABLY IN RESPONSE TO FLUID PRESSURE ON THE SIDE OF THE PISTON IN THE DIRECTION OF RETRACT THE PISTON FROM THE LIMIT POSITION.