HOLE REAMER Russian patent published in 1995 - IPC

FIELD: mining art. SUBSTANCE: hole reamer has case provided with grooves being curvilinear at longitudinal cross-section and axial washing channel, extensible rock-breaking tools which are mounted inside the grooves and have working surface, curvilinear support surface which follows profiles of grooves of the case, and hydraulic chamber. Hole reamer is provided with annular piston with restrictor holes; the piston is disposed inside the hydraulic chamber for interaction with lower edges of rock-breaking tools. Hydraulic chamber is made in form of annular cavity and connected with axial washing channel. Top part of working surface of rock-breaking tools when they are withdrawn is disposed higher than cross-section of grooves is disposed, the cross-section has maximal radius of curvilinear surface. EFFECT: improved efficiency of operation. 3 dwg