Hydraulically actuated orienting device

Claim 1

AN ORIENTING SUB FOR INSERTION IN A DRILL STRING FOR EARTH BORING OPERATIONS COMPRISING: AN OUTER TUBULAR MEMBER HAVING A BORE THERETHROUGH; A TUBULAR PISTON IN SAID BORE AXIALLY AND RADIALLY MOVABLE THEREIN AND HAVING AT LEAST ONE ORIFICE IN ITS WALL NEAR ITS LOWER END, AN EXTERNAL ANNULAR SHOULDER HAVING A DOWNWARDLY FACING NOTCH THEREIN, AND A RESTRICTED OPENING AT ITS LOWER END DEFINING A FIRST OUTLET PASSAGE CONSTITUTING AN OUTLET AREA FOR THE PASSAGE OF DRILLING FLUID FROM SAID SUB; THE HOLLOW OF SAID PISTON FORMING A PASSAGEWAY FOR DRILLING FLUID THROUGH SAID SUB; A TUBULAR SEAL BETWEEN SAID PISTON AND SAID BORE LOCATED BELOW SAID EXTERNAL SHOULDER AND HAVING AN INTERNALLY RECESSED PORTION AT ITS LOWER END TO FORM AN ANNULAR RECESS BETWEEN ITS LOWER INTERNAL SURFACE AND SAID PISTON, THE UPPER END OF SAID SEAL AND THE LOWER SURFACE OF SAID EXTERNAL SHOULDER DEFINING AN ANNULAR RACE; MEANS FOR INDICATING THE ORIENTATION OF SAID PISTON AND SAID NOTCH RADIALLY WITH RESPECT TO SAID OUTER TUBULAR MEMBER; MEANS FOR SECURING SAID POSTON IN ORIENTED POSITION AGAINST RADIAL MOVEMENT; MEANS FOR EQUALIZING PRESSURE BETWEEN SAID RACE AND THE HYDROSTATIC HEAD OF THE WELL BORE; A SECOND OUTLET PASSAGE FROM SAID PASSAGEWAY DEFINED BY SAID ORIFICES AND SAID ANNULAR RECESS; SEALING MEANS CARRIED BY