BOREHOLE PUNCH FOR PIPES Russian patent published in 1996 - IPC

FIELD: underground repair of holes. SUBSTANCE: borehole punch is provided with hollow plunger mounted in area of cylinder and forming working chamber together with it which is equipped with ducts communicating plunger space with rod chamber and connected with shearing member to rod made fast to shifter having upper thrust surface and holes communicating its space with space of hole. Cone rigidly connected to working string and shearing member with shifter and check valve are mounted in shifter for axial movement and interaction with thrust surface of shifter. Check valve is manufactured in the form of crushed stopper and is put in shifter for interaction with cone it the latter is displaced axially to communicate shifter space to working chamber. In this case axis of side duct of body is located at angle to plane perpendicular to direction of axial movement of rod. Angle between axis of side duct of body and plane perpendicular to direction of axial movement of rod is chosen within 25 deg. EFFECT: enhanced operational reliability of punch and expanded functional capabilities of it. 2 cl, 3 dwg