A concentric follow pipe drilling tool

Abstract

The invention relates to a drilling tool, in particular to a concentric simultaneous casing drilling tool, which comprises a connector (1), wherein a central drill bit (2) is glidingly connected onto the connector (1); an arc groove is formed in the connector (1) between the connector (1) and the central drilling bit (2); at least two expanding drill sheets (3) are uniformly distributed along the central drill bit (2) between the connector (1) and the central drill bit (2); the root parts of the expanding drill sheets (3) are arranged in the arc groove; embossments (4) are arranged at the end parts of the connector (1) between the two adjacent expanding drill sheets (3); and the two sides of each embossment (4) abut on the expanding drill sheets (3). The expanding drill sheets (3) do not swing in the tangential direction as the expanding drill sheets (3) are jammed by the embossments (4) in the tangential direction when the concentric simultaneous casing drilling tool rotates, so that the expanding drill sheets (3) are prevented from being ruptured due to swing caused by tangential impact.

Description

technical field [0001] The invention relates to a drilling tool, in particular to a concentric and tubular drilling tool. Background technique [0002] In building construction, concentric follower drilling is a new drilling technology developed on the basis of down-the-hole drilling technology. Successfully drilled and formed holes effectively, and the concentricity of the holes is high. [0003] In the construction of concentric follower pipe drilling, concentric follower pipe drilling tools are used for drilling. The current concentric follower pipe drilling tools mainly include connectors, center drill bits and reaming drill pieces. The reaming drill pieces are usually multi-piece and The center bit is evenly distributed between the connector and the center bit; when the drilling tool is not working, the reaming drill piece is contracted. When the drilling tool is working, the center bit moves upwards to drive the expansion The drill piece expands outward until both th...

AI Technical Summary

Problems solved by technology

However, because the reaming drill piece is clamped between the connector and the center drill bit, it is clamped by the connector and the center drill bit during work, so when the drilling tool rotates, the tangential impact force of the rock, soil, sandstone, etc. on the reaming drill piece will cause The reaming drill piece swings in the circumferential direction along the center drill bit, so that the reaming drill piece is often broken due to impact

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