Self-synchronizing load lifting and lowering system for straddle carriers and the like

Claim 1

FOR USE WITH A STRADDLE CARRIER HAVING A FRAME AND A FLUID RESERVOIR, A SELF-SYNCHRONIZING LOAD LIFTING AND LOWERING SYSTEM COMPRISING: LOAD ENGAGING MEANS, A PLURALITY OF LOAD LIFTING MECHANISMS, EACH MECHANISM INCLUDING: A FLUID MOTOR CONNECTED TO THE FRAME AND THE SAID LOAD ENGAGING MEANS, THE SAID MOTOR HAVING: A CYLINDER CONNECTED TO THE SAID LOAD ENGAGING MEANS, THE SAID CYLINDER HAVING A HEAD END AND A ROD END, A PISTON SLIDABLY DISPOSED IN THE SAID CYLINDER AND A PISTON ROD CONNECTED TO THE SAID PISTON AND THE FRAME AND EXTENDING THROUGH THE SAID CYLINDER ROD END, A MOTOR CONTROL AND SYNCHRONIZING VALVE INCLUDING: A BODY, A BORE IN THE SAID BODY, INLET, OUTLET, FIRST AND SECOND MOTOR PORTS DISPOSED IN THE SAID BODY AND COMMUNICATING WITH THE SAID BORE, THE SAID OUTLET PORT BEING CONNECTED TO COMMUNICATE WITH THE FLUID RESERVOIR, THE SAID FIRST MOTOR PORT BEING CONNECTED TO COMMUNICATE WITH THE SAID CYLINDER ADJACENT THE SAID ROD END AND THE SAID SECOND MOTOR PORT BEING CONNECTED TO COMMUNICATE WITH THE SAID CYLINDER ADJACENT THE SAID HEAD END, AND A SPOOL SLIDABLY DISPOSED IN THE SAID BORE THE SAID BODY AND SPOOL BEING MOVABLE RELATIVE TO EACH OTHER FROM A FIRST POSITION IN WHICH FLUID COMMUNICATION BETWEEN THE SAID INLET AND OUTLET PORTS AND THE SAID MOTOR PORTS IS BLOCKED TO EITHER A SECOND POSITION IN WHICH THE SAID INLET PORT IS PLACED IN FLUID COMMUNICATION WITH THE SAID FIRST MOTOR PORT AND THE SAID OUTLET PORT IS PLACED IN FLUID COMMUNICATION WITH THE SAID SECOND MOTOR PORT OR A THIRD POSITION IN WHICH THE SAID INLET PORT IS PLACED IN FLUID COMMUNICATION WITH THE SAID MOTOR PORT AND THE SAID OUTLET PORT IS PLACED IN FLUID COMMUNICATION WITH THE SAID FIRST MOTOR PORT, A VALVE ACTUATING MOTOR FOR MOVING THE SAID VALVE BODY BETWEEN THE SAID FIRST, SECOND AND THIRD POSITIONS RELATIVE TO THE SAID SPOOL AND INCLUDING: AN ELONGATED CYLINDER WITH A HEAD END AND A ROD END, THE SAID ACTUATING MOTOR CYLINDER BEING FIXED TO THE SAID VALVE BODY, A FIRST PORT COMMUNICATING WITH THE SAID ACTUATING MOTOR CYLINDER ADJACENT THE SAID SAID ROD END THEREOF AND A SECOND PORT COMMUNICATING WITH THE SAID ACTUATING MOTOR CYLINDER ADJACENT THE SAID HEAD END THEREOF, A PISTON SLIDABLY DISPOSED IN THE SAID ACTUATING MOTOR CYLINDER,