Air-oil shock absorber especially adapted for ground vehicles

Claim 1

A SHOCK ABSORBING DEVICE WHICH IS CONNECTED BETWEEN A PAIR OF SHOCK RECEIVING ELEMENTS, FOR CUSHIONING ABRUPT SHOCKS TENDING SUDDENLY TO MOVE ONE OF SAID ELEMENTS TOWARD AND FROM THE OTHER, SAID DEVICE COMPRISING: A CYLINDER FIXED TO ONE OF SAID ELEMENTS AND PROVIDING A MAIN CHAMBER ADAPTED TO CONTAIN SUBSTANTIALLY INCOMPRESSIBLE LIQUID; A HOLLOW PISTON AXIALLY TELESCOPINGLY SLIDABLE IN THE CYLINDER AND CONNECTED WITH THE OTHER OF SAID ELEMENTS FOR MOVEMENT THEREWITH; MEANS DEFINING A MOVABLE WALL IN THE HOLLOW INTERIOR OF THE PISTON OPPOSING AND COOPERABLE WITH THE OUTER END PORTION THEREOF TO DEFINE A VARIABLE VOLUME PRESSURE CHAMBER IN THE PISTON IN WHICH COMPRESSIBLE MEDIUM IS MAINTAINED UNDER A PRESSURE WHICH HAS A PREDETERMINED MINIMUM VALUE WHEN THE PRESSURE CHAMBER IS AT MAXIMUM VOLUME; MEANS DEFINING A RESTRICTED PASSAGE COMMUNICATING THE MAIN CHAMBER WITH THE PRESSURE CHAMBER AT THE SIDE OF THE MOVABLE WALL ADJACENT TO THE INNER END OF THE PISTON, TO CAUSE THE MOVABLE WALL TO MOVE IN RESPONSE TO CHANGES IN PRESSURE OF THE LIQUID, DUE TO MOVEMENT OF THE PISTON RELATIVE TO THE CYLINDER, AND TO TRANSMIT SUCH PRESSURE CHANGES TO THE COMPRESSIBLE MEDIUM IN THE PRESSURE CHAMBER, THE RESTRICTION OF SUCH PASSAGE MEANS PROVIDING FOR RETARDATION OF PISTON MOVEMENT RELATIVE TO THE CYLINDER; A SECOND VARIABLE VOLUME PRESSURE CHAMBER, COMPRISING MEANS FIXED WITH RESPECT TO THE CYLINDER AND A SECOND WALL MOVABLE IN OPPOSITE DIRECTIONS TO INCREASE AND DECREASE THE VOLUME OF THE SECOND PRESSURE CHAMBER; AT ONE SIDE OF SAID SECOND MOVABLE WALL; MEANS PROVIDING ANOTHER RESTRICTED PASSAGE COMMUNICATING THE MAIN CHAMBER WITH SAID SECOND PRESSURE CHAMBER AT THE OTHER SIDE OF SAID SECOND MOVABLE WALL WHEREBY THE LATTER IS CAUSED TO BE MOVED IN RESPONSE TO CHANGES IN PRESSURE OF THE LIQUID; AND MEANS DEFINING A PREDETERMINED LIMIT OF MOTION OF SAID SECOND MOVABLE WALL IN THE DIRECTION TO INCREASE THE VOLUME OF SAID SECOND PRESSURE CHAMBER, TO ENABLE SAID SECOND CHAMBER TO BE FILLED WITH COMPRESSIBLE MEDIUM AT A SUBSTANTIALLY HIGHER PREDETERMINED PRESSURE THAN THE FIRST CHAMBER, SO THAT SAID SECOND MOVABLE WALL HAS NO TENDENCY TO MOVE IN RESPONSE TO INCREASING LIQUID PRESSURE UNTIL THE VOLUME OF THE FIRST CHAMBER HAS BEEN REDUCED TO A SUBSTANTIAL EXTENT BY COMPRESSION OF THE COMPRESSIBLE MEDIUM THEREIN.