Hydro-pneumatic vehicle suspension unit

Claim 1

A SELF-ADJUSTING HYDRO-PNEUMATIC SPRING SUSPENSION UNIT FOR A VEHICLE COMPRISING A CYLINDER, AN ANNULAR RESERVOIR SURROUNDING THE CYLINDER AND HAVING ITS INNER WALL FORMED BY THE CYLINDER, A PRESSURE CHAMBER COMMUNICATING WITH A FIRST END OF SAID CYLINDER AND CONTAINING A LIQUID AND A GAS, A PISTON WORKING IN THE CYLINDER, A PISTON-ROD OF LESS DIAMETER THAN THE CYLINDER CARRYING SAID PISTON, A CLOSURE FOR THE SECOND END OF THE CYLINDER THROUGH WHICH SAID PISTON-ROD WORKS, THE PISTON AND THE END CLOSURE DEFINING THE ENDS OF AN ANNULAR PUMPING SPACE OF VARIABLE AXIAL LENGTH BETWEEN THE PISTON-ROD AND THE CYLINDER, A PASSAGE CONNECTING SAID PUMPING SPACE WITH THE FIRST END OF THE CYLINDER, A FIRST ONE-WAY VALVE IN SAID PASSAGE PERMITTING FLOW ONLY FROM THE PUMPING SPACE INTO THE FIRST END OF THE CYLINDER, A SECOND PASSAGE CONNECTING SAID PUMPING SPACE WITH THE RESERVOIR, A ONE-WAY VALVE IN SAID PASSAGE PERMITTING FLOW ONLY FROM THE RESERVOIR INTO THE PUMPING SPACE, AND A PORT IN THE CYLINDER WALL LEADING DIRECTLY AND FREELY INTO THE RESERVOIR AND CONTROLLED BY THE PISTON, SAID PORT PERMITTING FLOW DIRECTLY FROM THE FIRST END OF THE CYLINDER TO THE RESERVOIR AT A PREDETERMINED AXIAL POSITION OF THE PISTON.