Abstract: A jarring device for use in drilling comprises first and second members longitudinally relatively movable between a locked position and a released position said device comprising control means including a pair of locking devices each arranged to prevent relative movement between said members until a predetermined force is applied to one of said movable members in either of two longitudinal directions. The control means includes two locking devices each of which locks in one of the two directions.The locking devices may comprise pivotable bolts pivoted on a sliding member so that the free ends of the bolts contact an abutment on one of the movable members to effect locking, the bolts being retracted from engagement with the abutment by movement of the sliding member.

Abstract: A high-pressure sealing means for two parts of deep-well drilling tools which are longitudinally movable in relation to one another consists of a wearing sealing ring (7) which is disposed in an annular groove in a first part (1) and bears against the second part (2) and prestressed radially by a pressure ring (14). The wearing sealing ring (7) has a wall surface (13) extending substantially over its axial length, which seals against the second part (2). Moreover the ring (13) is smaller than the width of the annular groove (3) of the first part (1) receiving it and is displaceable between the two sides (4,5) of the annular groove for the selective formation of a static sealing surface at one of the sides (4,5) of the annular groove. The pressure ring (14) is formed from elastomer material, has a large volume, and is gripped, compressed and deformed between the wall surface (10) of the wearing sealing ring (7) situated opposite the sealing wall surface (13) and the bottom (6) of the annular groove.

Abstract: A locking device for a tool with telescopically displaceable parts such as the various tools including a drilling jar used in the deep-well drilling art comprises thickened spindle portion (1) and a sleeve portion (2) with a displaceable sleeve (11) displaceable therein to and away from an axial abutment (17). The thickening of the spindle portion provided by a rigid tapered sleeve (3) with tapered end surfaces (5 and 6) and the sleeve (11) within the sleeve portion with an internal tapered surface (12) are coupled via locking balls (19) disposed for radial movement in an annular cage 20 between the rigid and displaceable sleeves 3 and 11. The sleeve (11) is held by an axial spring (16) in such a position that the balls come to lie axially between the axial abutment (17) and a region of the tapered sleeve (3) having a larger diameter and thereby form a constriction to the passage of the sleeve (3) of the spindle portion ( 11).