The invention relates to a composite
drill bit capable of changing a
rock cutting mode without pulling out of a hole, which belongs to a drilling exploration tool and comprises a
drill bit base body and a centralizing edge arranged on the periphery of the
drill bit base body and integrated with the
drill bit base body, the centralizing edge is formed by alternately arranging a fixed
drill bit mounting seat and convex edges, and the length of the fixed
drill bit mounting seat is greater than that of the lower edge of the drill bit base body; a cavity is formed in the lower portion of the drill bit base body. A movable seat is mounted in the cavity, movable drill bit mounting seats are fixed below the movable seat, a moving channel is formed between the movable drill bit mounting seats and below the movable seat, a flow guide
pipe is arranged in the drilling tool connector and penetrates through the cavity and the movable seat, the lower end of the flow guide
pipe is arranged in the moving channel, and a plurality of flow guide holes are formed in the periphery of the outer wall of the lower middle section of the flow guide
pipe. According to the device, the drill bit can be rapidly replaced under the condition of not pulling out a hole, the device is suitable for a stratum structure where heterogeneous rocks (
conglomerate rocks) and homogeneous rocks frequently and alternately occur, the non-working time occupied by pulling out the hole and replacing the drill bit is shortened, the drilling cost is reduced, the labor intensity of workers is reduced, and the drilling efficiency is improved.