DRILLING BIT Russian patent published in 2009 - IPC E21B10/02 

FIELD: mining.

SUBSTANCE: present invention pertains to drilling bits, designed for drilling with continuous removal of core material. The drilling bit has housing with a working butt end, reinforced by concentric well-, core-forming and intermediate cutters, and an inner core tube, put inside the housing, and the cavity between them is connected to the annular space by radial channels in the housing. The core-forming cutters are L-shaped. Their transverse part is located on the side of the longitudinal axis of the drill bit. The height of the transverse part and the overall height of the cutters have the following relationship: h≤0.5(H-ΔH), where h is the height of the transverse part of the cutters, H is the overall height of the cutters and ΔH is the height of the cutters, projecting above the butt end. The number of core forming cutters is more than the number of cutters in the adjacent row. Gap a, between the inner surface of the drill bit and the housing, and gap b, between the inner surface of the drill bit and the inner core tube have the following relationship: a=(0.5-0.6)·b. Such a drill bit increases integrity of the core, increases accuracy of locating rocks transported to the drilling interval and increases efficiency of prospecting as a whole.

EFFECT: increased integrity of the core, increased accuracy of locating rocks transported to the drilling interval and increased efficiency of prospecting as a whole.

3 cl, 2 dwg