Seal for a suspension drilling device

Claim 1

IN COMBINATION WITH A DRILL STRING, A TUBULAR BODY CONNECTED AT ONE END THEREOF TO A SECTION OF SAID DRILL STRING, A TUBULAR MANDREL SLIDABLY MOUNTED IN SAID BODY AND EXTENSIBLE THEREFROM, THE EXTENDING END OF SAID MANDREL BEING CONNECTED TO ANOTHER SECTION OF THE DRILL STRING, MEANS LIMITING LONGITUDINAL SLIDING MOVEMENT OF SAID MANDREL AND MEANS LIMITING ROTATIONAL MOVEMENT OF THE MANDREL IN SAID BODY, THE END PORTION OF SAID MANDREL IN SAID BODY BEING DIAMETRICALLY REDUCED AND PROVIDING AN ABUTMENT SHOULDER, A FIRST RADIALLY EXPANSIBLE SEAL UNIT POSITIONED ON SAID REDUCED PORTION OF THE MANDREL IN ABUTMENT WITH SAID SHOULDER, A SECOND RADIALLY EXPANSIBLE SEAL UNIT POSITIONED ON SAID REDUCED MANDREL PORTION IN SPACED RELATION FROM SAID FIRST SEAL UNIT, RESILIENTLY COMPRESSIBLE MEANS INTERPOSED BETWEEN THE FIRST AND SECOND SEAL UNITS FOR SPACING THE SAME APART, AND A SCREWTHREADED ELEMENT POSITIONED ON SAID REDUCED MANDREL PORTION IN ABUTMENT WITH SAID SECOND SEAL UNIT, WHEREBY UPON TIGHTENING OF SAID SCREW-THREADED ELEMENT SAID SEAL UNITS MAY BE RADIALLY EXPANDED INTO ENGAGEMENT WITH THE INSIDE SURFACE OF SAID TUBULAR BODY.