PNEUMATIC DRILLING DEVICE Russian patent published in 2003 - IPC

FIELD: mining industry, particularly, sinking pneumatic percussion machines applicable, for instance, in drilling holes of large diameters. SUBSTANCE: device includes body with chambers of forward and reverse strokes, hollow piston-striker, central air distributing tube, reducer and box with crown bit. Box has through holes communicating reverse stroke chamber with longitudinal bores of crown bit shank for separation of compressed air flow with oil aerosols into two flows. One flow through clearances of contact surfaces of crown bit shank-box pair directly to atmosphere and the other flow is also directed to atmosphere but through clearances of contact surfaces of crown bit. EFFECT: increased impact energy and prolonged service life of claimed pneumatic drilling device. 1 dwg