Shock absorbing and static load supporting drill string apparatus

Claim 1

IN AN APPARATUS FOR INSERTION INTO A DRILL STRING AND HAVING UTILITY FOR ABSORBING SHOCK LOADING AND FOR SUPPORTING STATIC LOADING EXISTING IN THE DRILL STRING, SAID APPARATUS COMPRISING: A TUBULAR BODY HAVING ONE END PORTION ADAPTED TO BE SECURED TO A DRILL STRING MEMBER; A PISTON MEMBER HAVING ONE END PORTION ALSO ADAPTED TO BE SECURED TO A DRILL STRING MEMBER, SAID PISTON MEMBER BEING RECIPROCABLY CARRIED BY SAID BODY TO DEFINE THEREWITH A SEALED PRESSURE TRANSMITTING LIQUID CHAMBER AND AN AXIAL PASSAGE THROUGH WHICH DRILLING FLUID MAY FLOW TOWARD THE BORE HOLE BOTTOM; A SEALED GAS CAVITY FORMED INTERNALLY IN A SELECTED ONE OF SAID TUBULAR BODY AND SAID PISTON MEMBER TO COMMUNICATE WITH SAID LIQUID CHAMBER; A MOVABLE SEPARATION ELEMENT SEPARATING THE GAS IN SAID GAS CAVITY AND SAID LIQUID TO PREVENT THE INTERMINGLING OF GAS LIQUID AND TO TRANSMIT BY MOVEMENT THE FLUID PRESSURE OF THE LIQUID TO THE GAS; AND VALVE MEANS EXTENDING THROUGH SAID TUBULAR BODY AND INTO SAID SEALED GAS CAVITY WHEREBY THE PRESSURE IN THE GAS CAVITY MAY BE SELECTIVELY VARIED.