Hydraulic actuator fitted with pivoted joint

Claim 1

A HYDRAULIC ACTUATOR COMPRISING: A CYLINDER; A PISTON MADE OF TWO HOLLOW PISTON SECTIONS DISPOSED IN SAID CYLINDER AND DIVIDING SAID CYLINDER INTO TWO VARIABLE-VOLUME WORKING CHAMBERS FOR LONGITUDINAL DISPLACEMENT IN UNISON RELATIVE THERETO AND FORMING A SPACE THEREBETWEEN FOR AUTOMATIC TAKE-UP MOVEMENT TOWARD EACH OTHER; FIRST MEANS DEFINING A COAXIAL, ANNULAR INTERNAL BEARING SURFACE IN THE INTERIOR OF SAID FIRST PISTON SECTION, SECOND MEANS DEFINING A SIMILAR COAXIAL, ANNULAR INTERNAL BEARING SURFACE IN THE INTERIOR OF SAID SECOND PISTON SECTION; A BACKLASH-FREE PIVOTAL BEARING MEANS CLAMPED BETWEEN SAID FIRST AND SECOND PISTON SECTIONS, AND ROTATABLE RELATIVE THERETO, HAVING A FIRST PORTION DEFINING AN ANNULAR EXTERNAL BEARING SURFACE WHICH ENGAGES SAID INTERNAL BEARING SURFACE OF SAID FIRST PISTON, AND HAVING A SECOND PORTION DEFINING AN ANNULAR EXTERNAL BEARING SURFACE WHICH ENGAGES SAID INTERNAL BEARING SURFACE OF SAID SECOND PISTON, SAID EXTERNAL SURFACES IN SAID PORTIONS OF SAID PIVOTAL BEARING MEANS BEING DUAL-BASE SPHERICAL SEGMENTS OF SUBSTANTIALLY EQUAL RADIUS WITH A COMMON CENTER; AND AT LEAST ONE THRUST LINK MOUNTED ON ONE OF SAID PORTIONS OF SAID PIVOTAL BEARING MEANS AND EXTENDING THROUGH ONE OF SAID HOLLOW PISTON SECTIONS.