BORE-HOLE MAGNETIC CATCHER Russian patent published in 1997 - IPC

FIELD: mining industry. SUBSTANCE: in repair and restoration of bore-holes for extraction of broken tools, equipment and other ferromagnetic parts including hard-alloy rotary bit teeth, use is made of bore-hole magnetic catcher having circular cylindrical body with adapter and cutting mill bit. Installed in body is magnetic system with washing passages located on peripheral magnetic circuit. Magnetic system has peripheral magnetic circuit and coaxial central magnetic circuit made of magnetically soft material. Located between them are permanent magnets. Central magnetic circuit can be made in the form of cone, truncated cone, multiface pyramid or truncated multiface pyramid with their bases directed towards catcher end face. Catcher is additionally provided with protective diamagnetic strips located above and below magnetic system. Catcher possesses enhanced attractive force acting at large distances with retention of holding force. Mass of permanent magnets and entire catcher is reduced. EFFECT: increased specific load lifting capacity and service life, simplified manufacture and assembly. 4 cl, 6 dwg