HYDRAULIC DRILLING JAR Russian patent published in 2007 - IPC E21B31/113 

FIELD: drilling equipment, particularly devices to create impact loads for stuck drilling string section freeing from oil or gas well.

SUBSTANCE: device comprises tubular body and mount slidably connected with each other so that the components are restricted from rotation. Tubular body has slots formed in outer surface thereof, inner anvil extensions, the first sealing member arranged from the first end side. Mount has slots in inner surface, belt having increased diameter, percussion means arranged between anvil extensions, the second sealing member arranged in percussion means from the side of the second body end and defining working liquid chamber. Mount also has circular valve having annular side surface, two ends, outer surface and inner surface defined by inner cavity, as well as restriction mechanism, which restricts working liquid communication with one section of working liquid chamber. The restriction mechanism is installed in working liquid chamber and has mount extending through inner cavity and located inside body. The restriction mechanism includes at least one bypass valve arranged in circular valve, which restricts working liquid flow inside one chamber section in one direction. Inner circular valve surface is in tight contact with mount belt having increased diameter. Circular valve travel is limited by two stops projecting from inner body surface and is equal to at least difference between inner and outer surface radii. Stop, which limits longitudinal circular valve travel towards percussion means with the second sealing member installed therein is defined by projection extending from inner body surface having decreased diameter adapted to be slidably connected to the second sealing member of percussion means. At least one percussion means arranged in working liquid chamber has self-sealing member. Diameter of each inner body surface is equal to that of mount, which defines movable connection with the first sealing member arranged in the body.

EFFECT: increased reliability and service life, prevention of uncontrolled device actuation.

3 cl, 5 dwg