Hydraulic operating system for opening bridges

Claim 1

IN COMBINATION WITH A BRIDGE SPAN PIVOTALLY MOUNTED ABOUT A FIXED AXIS, MEANS FOR MOVEMENT OF THE SPAN BETWEEN A LOWERED POSITION AND AN ELEVATED POSITION COMPRISING A PAIR OF LATERALLY SPACED FLUID MOTOR DEVICES HAVING PISTONS CONNECTED TO THE SPAN FORWARDLY OF THE FIXED AXIS AND FLUID OPERATING MEANS CONNECTED TO SAID MOTOR DEVICES FOR EXTENSION AND RETRACTION OF THE PISTONS BY EQUAL AMOUNTS TO ELEVATE AND LOWER SAID SPAN, AND MEANS MOUNTING THE MOTOR DEVICES FOR PIVOTAL DISPLACEMENT DURING SAID MOVEMENT OF THE SPAN FROM A SUBSTANTIALLY VERTICAL POSITION IN BOTH THE LOWERED AND ELEVATED POSITIONS OF THE SPAN, SAID FLUID OPERATING MEANS INCLUDING, FLUID PRESSURE SUPPLY MEANS, DIRECTIONAL CONTROL MEANS OPERATIVELY CONNECTING THE SUPPLY MEANS TO THE FLUID MOTOR DEVICES FOR EXTENSION OR RETRACTION OF THE PISTONS, STROKE LIMITING MEANS OPERATIVELY CONNECTED TO THE MOTOR DEVICES FOR DECLERATING MOVEMENT OF THE PISTONS AS THE SPAN APPROACHES THE LOWERED OR ELEVATED POSITIONS THEREOF, AND OVERLOAD RESPONSIVE MEANS OPERATIVELY CONNECTED TO THE MOTOR DEVICES FOR LIMITING PRESSURE DEVELOPED THEREIN.