Hydraulic locking device with stroke adjusting means

Claim 1

IN A LOCKING DEVICE TO CONTROL RELATIVE MOVEMENT BETWEEN TWO MEMBERS, COMPRISING A HYDRAULIC CYLINDER CONNECTED TO ONE OF THE TWO MEMBERS, A PISTON ROD EXTENDING THROUGH BOTH ENDS OF SAID CYLINDER AND CONNECTED TO THE OTHER OF THE TWO MEMBERS, A PISTON UNITED WITH SAID PORTION ROD AND DIVIDING THE INTERIOR OF SAID CYLINDER INTO TWO LOCKING CHAMBERS, AND A LOCKING VALVE CONTROLLING FLUID FLOW BETWEEN THE TWO CHAMBERS TO CONTROL THE FREEDOM OF MOVEMENT OF SAID PISTON, THE IMPROVEMENT COMPRISING: LONGITUDINAL GUIDE MEANS FORMING A GUIDE SLOT EXTENDING LONGITUDINALLY BEYOND ONE END OF SAID CYLINDER; COOPERATING MEANS CARRIED BY THE CORRESPONDING END OF SAID PISTON ROD IN SLIDING ENGAGEMENT WITH SAID SLOT AND GUIDED ALONG A STRAIGHT PATH THEREBY TO PREVENT RELATIVE ROTATION BETWEEN THE CYLINDER AND THE PISTON ROD; AND MEANS TO LIMIT THE RANGE OF MOVEMENT OF SAID PISTON ROD, SAID LIMITING MEANS BEING ADJUSTABLE ACROSS THE GUIDE SLOT AT SELECTED POINTS TO BLOCK THE PATH OF SAID COOPERATING MEANS THEREBY TO LIMIT THE RANGE OF RELATIVE MOVEMENT BETWEEN THE TWO MEMBERS SELECTIVELY.