DEVICE TO FORM DIRECTED CRACKS IN WELLS (VARIANTS) Russian patent published in 2006 - IPC E21C37/06 E21C37/02 

FIELD: mining, particularly to form cracks in wells to separate thereof from rock massif, for rock blocks mining and to break oversize stones.

SUBSTANCE: device in accordance with the first embodiment comprises cylindrical body with annular extension provided with percussion mechanism installed at cylindrical body end. Cylindrical body has sharpened free end and is made as bidentate wedge with dent angle α, having V-shaped cutting edge and two V-shaped vertical slots arranged from opposite sides of V-shaped cutting edge. Each above groove is defined by two planes arranged so that angle β<180° is created in-between. The planes form working edges of the bidentate wedge. Device in accordance with the second embodiment comprises cylindrical body with annular extension on free end thereof. The body is provided with percussion mechanism installed on cylindrical body end. The cylindrical body is provided with removable shell formed as two semi-cylinder coverings and may be axially displaced relative the semi-cylindrical coverings, which are provided with beams on outer sides thereof. The beams are located in upper covering parts.

EFFECT: increased operational efficiency due to creation of force directed to well wall and improved operational reliability due to simplified structure.

4 cl, 6 dwg