Articulated lifter with substantially constant jaw gripping factor

Claim 1

IN A LIFTER OF THE CHARACTER DESCRIBED, A LIFTER FRAMEWORK, A JAW-SUPPORTING HEAD MOUNTED FOR FREE FLOATING VERTICAL SHIFTING MOVEMENTS ON THE FRAMEWORK, A PAIR OF JAW-SUPPORTING ARMS PIVOTALLY CONNECTED AT THEIR PROXIMATE ENDS TO SAID HEAD AT POINTS SPACED APART THEREON FOR SWINGING MOVEMENTS TOWARD AND AWAY FROM EACH OTHER, ONE OF THE POINTS BEING LOCATED ON ONE SIDE AND THE OTHER POINT BEING LOCATED ON THE OPPOSITE SIDE OF THE CENTRAL VERTICAL AXIS OF THE HEAD, A PAIR OF OPPOSED OBJECTENGAGING JAWS CARRIED AT THE DISTAL ENDS OF SAID ARMS, SAID ARMS BEING MOVABLE IN UNISON BETWEEN A POSITION OF WIDE ANGULARITY THEREBETWEEN WHEREIN THE JAWS CARRIED THEREBY ARE WIDELY SEPARATED AND ARE FULLY OPEN, AND A POSITION OF SMALL ANGULARITY WHEREIN THE JAWS ARE IN CLOSE PROXIMITY TO EACH OTHER AND ARE FULLY CLOSED, A PAIR OF THRUST LINKS, ONE FOR EACH ARM, EACH HAVING ONE END THEREOF PIVOTED TO ITS RESPECTIVE ARM MEDIALLY THEREOF AND THE OTHER END THEREOF PIVOTED TO THE FRAMEWORK, THE POINT OF PIVOTAL CONNECTION BETWEEN EACH THRUST LINK AND THE FRAMEWORK BEING OFFSET LATERALLY OUTWARDLY FROM THE VERTICAL PLANE PASSING THROUGH THE POINT OF PIVOTAL CONNECTION BETWEEN THE RESPECTIVE ARM AND THE HEAD AND NORMAL TO THE PLANE OF SWINGING MOVEMENT OF THE ARMS, WHEREBY SAID JAW-SUPPORTING ARMS, IN MOVING FROM THEIR POSITIONS OF WIDE ANGULARITY TO THEIR POSITIONS OF SMALL ANGULARITY, WILL MOVE INITIALLY TOWARD POSITIONS OF ALIGNMENT WITH THE RESPECTIVE THRUST LINKS TO WHICH THEY ARE PIVOTED AND EFFECT RAISING MOVEMENTS OF THE HEAD, AND THEREAFTER WILL MOVE AWAY FROM SUCH POSITIONS OF ALIGNMENT AND EFFECT LOWERING OF THE HEAD, THE LENGTH OF SAID ARMS BEING SUCH, AND THE POINTS OF PIVOTAL CONNECTION BETWEEN THE ARMS AND THEIR RESPECTIVE THRUST LINKS BEING SO LOCATED, THAT DURING MOVEMENT OF THE ARMS BETWEEN THEIR POSITIONS OF WIDE AND SMALL ANGULARITY THE JAWS CARRIED THEREBY WILL TRAVEL IN SUBSTANTIALLY STRAIGHT DOWNWARDLY AND INWARDLY INCLINED LINEAR PATHS, AND MEANS CONSTRAINING SAID ARMS TO MOVE TOWARD AND AWAY FROM EACH OTHER IN UNISON.