Hydraulic shock absorber with initial impact damping

Claim 1

IN A DIRECT ACTING HYDRAULIC SHOCK ABSORBER COMPRISING A TUBULAR CYLINDER HAVING A BORE CLOSED BY A FOOT VALVE AT ONE END, MEANS DEFINING A RESERVOIR CONTIGUOUS TO THE CYLINDER AND WITH WHICH THE CYLNDER BORE COMMUNICATES THROUGH SAID FOOT VALVE, A CLOSURE BEARING CLOSING THE OPPOSITE END OF THE CYLINDER BORE, A PISTON RECIPROCABLY OPERABLE IN THE CYLINDER BORE AND HAVING A PISTON ROD EXTENDING THROUGH SAID CLOSURE BEARING, THE PISTON DIVIDING THE CYLINDER BORE INTO A COMPRESSION CHAMBER BETWEEN THE PISTON AND THE FOOT VALVE AND A REBOUND CHAMBER BETWEEN THE PISTON AND THE CLOSURE BEARING, BOTH OF SAID CHAMBER BEING FILLED WITH HYDRAULIC FLUID AND THE PISTON HAVING METERING ORIFICE MEANS THERETHROUGH FOR SHOCK DAMPING DISPLACEMENT OF HYDRAULIC FLUID BETWEEN SAID CHAMBERS THROUGH THE ORIFICE MEANS IN THE RECIPROCATIONS OF THE PISTON WITHIN THE CYLINDER, THE IMPROVEMENT COMPRISING: A SUBSTANTIALLY SPHERICAL FREE FLOATING MASS IN SAID COMPRESSION CHAMBER BETWEEN SAIS FOOT VALVE AND SAID PISTON AND IN UNINTERRUPTED ALIGNMENT WITH SAID ORIFICE MEANS, SAID MASS BEING OF BULK COMPRESIBLE ELASTOMERIC MATERIAL A SUBSTANTIAL PART OF THE VOLUME OF WHICH COMPRISES GAS-FILLED, SMALL, UNCONNECTED, DISCRETE AND INDEPENDENTLY ACTING, GENERALLY BUBBLE-LIKE CELLS, SAID MASS BEING OF A DIAMETER ONLY SLIGHT LESS THAN THE DIAMETER OF SAID CYLINDER BORE, WHEREBY SHOCK WAVES CREATED BY PRESSURE SURGES OF A MAGNITUDE GREATER THAN CAN BE ACCOMMODATED BY THE ORIFICE MEANS WILL BE ABSORBED BY BULK COMPRESSION OF SAID MASS AND CONTINUED COMPRESSION MOVEMENT OF THE PISTON IS REFLECTED IN RAPIDLY INCREASING SPRING RATE RESISTANCE TO COMPRESSION OF SAID MASS AND DAMPING OTHERWISE PROCEEDING BY DISPLACEMENT OF HYDRAULIC FLUID THORUGH SAID ORIFICE MEANS AND SAID FOOT VALVE.