HYDRAULIC PUNCH FOR BOREHOLES DRILLING Russian patent published in 1995 - IPC

FIELD: boreholes drilling. SUBSTANCE: hydraulic punch for boreholes drilling has hollow body with central chamber and guiding parts. Upper part of body has head with central hole. Head has pipe to form upper pumping chamber between pipe and head. Lower part of body has drilling head. Piston hammer with enlarged central part to make hits on drilling head is, using guiding parts, mounted in the body. Guiding valve with inner cavity is located over piston hammer. Guiding valve is made in the form of control valve with blind upper butt, and is mounted so, that its body cavity, located over guiding valve, is capable to communicate with upper pumping chamber, as control valve being in its lower position, and with central canal of piston hammer, as control valve being in its upper position. Diameter of central chamber of body is bigger than diameter of central part of piston hammer. EFFECT: hydraulic punch is used in borehole drilling bits. 4 cl, 4 dwg