WELL TOOL WITH RADIALLY RETRACTABLE PARTS Russian patent published in 2008 - IPC E21B10/32 E21B7/28 E21B29/00 

FIELD: mining.

SUBSTANCE: well tool can be made in form of boring head, tube cutter or regulated equaliser. A well tool contains: case at least one radial extended part installed in the case and traveling between retracted and extended positions, jaw part operationally connected with the extended part and traveling against the case for extending of the extended part, and support part facilitating retracting of the extended part from the extended position. The support part is designed to facilitate travel of the extended part against the jaw part or the case for retraction of the extended part. The well tool also can comprise a driven part operationally connected with the extended part and designed to move the extended part in the direction of the extended position in response to changes of fluid medium pressure; it (the well tool) comprises also a packing part of two positions; in the first position the driven part is isolated from the influence of pressure changes, while in the second position the driven part is subject to influence of changes of pressure.

EFFECT: reliability and simplicity at operation of well tool.

50 cl, 19 dwg