MECHANICAL JAR Russian patent published in 2002 - IPC

FIELD: oil and gas producing industry; applicable in elimination of tools sticking in well drilling and workovers. SUBSTANCE: mechanical jar has body with anvil, rod with striker and uncoupling unit which consists of stop, retainer, collet and thread bushing. Retainer is located between stop and thread bushing and engageable with spring regulated by thread bushing which is installed in jar body low part. Collet is engageable by means of its lugs with retainer and stop for pressing retainer out of seat. EFFECT: higher operating reliability of mechanical jar due to provision of uncoupling unit with stop, retainer and thread bushing ensuring smooth regulation of operation force of uncoupling unit. 2 dwg