CUTTER AND PULL SPEAR Russian patent published in 2014 - IPC E21B29/00 E21B31/16 

FIELD: mining.

SUBSTANCE: device comprises a pipe cutter housing with a slot, where on the pin a cutter is mounted. Cutter moving unit is implemented as a bottom hydraulic cylinder, where a power piston with a plunger is installed, on the bottom end of which a tip with cone attachment, supported by spring-loaded cutter is installed. The bottom hydraulic cylinder is connected through the top end with the spear housing, in the openings of which the dies are mounted. The spear housing is connected through the top end with the upper hydraulic cylinder and is fitted with an expanding cone. The upper hydraulic cylinder comprises a ring piston with hollow stem connected with expanding cone of the spear, enclosed by dies. The top end of the hollow plunger forms movable connection with the expanding cone, which forms with the spear housing a cavity, hydraulically connected through a circulating hole in the hollow step body with its axial channel. The circulating hole in the initial position is shut with shutter with a sitting bevel fitted to a ball valve. The upper hydraulic cylinder of the device through a sleeve and sub is connected to a drilling string. The cutter is supported by a spring-loaded thruster in a bore of the pipe cutter housing, on external side of which a bearing box with a protective bush is installed.

EFFECT: improvement of reliability, expansion of technical capabilities.

3 cl, 3 dwg