UNIVERSAL CORE DRILL AND CORE DRILL BIT Russian patent published in 1994 - IPC

FIELD: well drilling. SUBSTANCE: universal core drill has casing 5 embracing ribs 10. Provided between annular channel 2 and casing 5 is through annular channel 11. Source of vibration excitation is made in form of ball. Length of core receiver 3 is shorter than distance between stop end face of body 2 and end face of core drill bit 1. Core catchers 12 may be spaced at 1.5-2.0 m. Body 14 of core drill bit 1 has percussive flat end 23 located above working blades 15. Side inclined channels 18 and 21 are located on side surfaces of vertical channels above and under ball vibrator 20. Channels 18 are communicated with hollow of body 14, and channels 21 are communicated with drill string-borehole annulus. Annular hollow 19 and vertical channels are located from the side of end face 23. Total area of cross-sections of side inclined channels 18 and 21 does not exceed 35-40% of total areas of vertical channels. EFFECT: higher efficiency. 4 cl, 3 dwg