Variable volume piston chamber in a shock absorber

Claim 1

A SHOCK ABSORBER COMPRISING AN ELONGATED HOUSING MEANS CONTAINING A FLUID, A PISTON ROD MOUNTED IN SAID HOUSING MEANS FOR MOVEMENT ALONG THE LENGTH THEREOF, A PISTON HEAD MOUNTED ON SAID PISTON ROD WITHIN SAID HOUSING MEANS, SAID PISTON HEAD BEING DISPOSED IN SEALING RELATION WITH SAID HOUSING MEANS TO PROVIDE UPPER AND LOWER FLUIT CHAMBERS, SAID PISTON HEAD HAVING A FIRST FLUID PASSAGEWAY COMMUNICABLE WITH SAID UPPER AND LOWER CHAMBERS, A CHECK VALVE MOUNTED ON SAID PISTON HEAD OPERABLE TO PERMIT FLUID FLOW THROUGH SAID FIRST FLUID PASSAGEWAY WHEN SAID PISTON IS MOVING IN A FIRST DIRECTION, SAID PISTON HEAD HAVING A SECOND FLUID PASSAGEWAY COMMUNICABLE WITH SAID UPPER AND LOWER CHAMBERS, A VALVE MEMBER DISPOSED ON SAID PISTON HEAD OPERABLE TO PERMIT FLUID FLOW THROUGH SAID SECOND PASSAGEWAY WHEN SAID PISTON HEAD IS MOVING IN A DIRECTION OPPOSITE FROM SAID FIRST DIRECTION, YIELDABLE MEANS FOR URGING SAID SECOND MENTIONED VALVE MEMBER IN A CLOSED POSITION, SAID PISTON HEAD HAVING A CHAMBER, A MOVABLE PISTON MEMBER MOUNTED ON SAID PISTON ROD RECEIVABLE WITHIN SAID CHAMBER AND OPERABLE TO VARY THE VOLUME OF SAID CHAMBER, THEREBY PROVIDING A VARIABLE VOLUME CHAMBER, MEANS FOR BIASING SAID PISTON MEMBER INTO SAID CHAMBER AND SAID SECOND MENTIONED VALVE MEMBER HAVING A RESTRICTED PASSAGEWAY PERMITTING COMMUNICATION BETWEEN SAID SECOND PASSAGEWAY AND SAID VARIABLE VOLUME CHAMBER.