BOREHOLE FISHING TOOL Russian patent published in 2006 - IPC E21B31/08 

FIELD: mining, particularly fishing for or freeing objects in boreholes or wells.

SUBSTANCE: fishing tool comprises body with pull means and auger with stepped shank spring-loaded in axial direction and arranged in body cavity. The fishing tool also comprises slurry trap and drive to provide auger rotation. The drive is made as screw self-releasing couple. Pull means is made as cable connected with auger shank so that pull means and auger shank may rotate with respect to each other. The body is made as reversed cup. Fishing tool auger has bearing assembly installed on the shank between cup bottom and spring. The body has striking mechanism made as hollow disc arranged on shank between upper body end and unit, which connects pull means with cable. The disc includes axial orifice having drift diameter less than diameter of larger auger shank step. Auger travel exceeds distance between lower end of striking mechanism and upper end of larger auger shank step. Auger travel is adjusted by washers freely installed on auger shank. Sludge trap is made as container with perforated bottom located below upper end of spiral auger blade.

EFFECT: reduced rime and labor inputs for equipment trips, simplified structure and increased operational efficiency.

5 cl, 1 dwg