| 摘要 |
FIELD: drilling equipment, particularly used for enlarging drilled bores. ^ SUBSTANCE: drilling tool used to increase diameter of previously drilled bore comprises body, drilling means comprising drilling bits and adapted to widen the bore to obtain well bore having the second diameter exceeding the first one. Guiding member advancing from above body and adapted to be installed in previously drilled bore guides drilling tool along the bore. Stabilizing surfaces having ribs extending along tool axis are coaxially arranged around the drilling tool between above drilling bits. Stabilizing surface is located behind drilling means. Above stabilizing surfaces may abut upon wall of bore having the second diameter, which provides reduction of transversal force applied to drilling means. ^ EFFECT: increased stability, which reduces side load applied to drilling means of drilling tool and increased efficiency. ^ 11 cl, 7 dwg |
