Belt and track tensioner

Claim 1

IN COMBINATION WITH AN ENDLESS TRACK OR BELT HAVING AT LEAST ONE TRACK-ENGAGING HEEL MOVABLY MOUNTED ON A FRAME MEMBER, ANU HYDRAULIC TENSIONER COMPRISING: AN HYDRAULIC ASSEMBLY INCLUDING ON OPEN-ENDED CYLINDER, A PISTON IN SAID CYLINDER, SAID PISTON HAVING RIDGE-RECEIVING ANNULAR PERIPHERAL GROOVES, AND MEANS COMMUNICATING WITH SAID CYLINDER WHEREBY FLUID IS INTRODUCED INTO AND RETAINED IN SAID CYLINDER TO MOVE SAID PISTON OUTWARDLY, SAID HYDRAULIC ASSEMBLY BEING ADAPTED ON OUTARD MOVEMENT OF SAID PISTON TO CAUSE MOVEMENT OF SAID MOVABLE WHEEL TO INCREASE TENSION ON SAID TRACK, AND LOCKING MEANS ENGAGING THE OPEN END OF SAID CYLINDER AND SAID PISTON TO PREVENT INWARD MOVEMENT OF SAID PISTON, INCLUDING A PAIR OF COOPERATING RING HALVES PROVIDED WITH ANNULAR INTERNAL RIDGES ADAPTED TO COOPERATE WITH SAID ANNULAR PERIPHERAL RIDGE-RECEIVING GROOVES ON SAID PISTON, AND MEANS SUBSTANTIALLY ENCIRCLING SAID RING HALVES FOR RESILIENTLY URGING SAID RIDGES IN ENGAGEMENT WITH SAID RIDGE-RECEIVING GROOVES.