US Patent 10081066 Self-locking head-replaceable carbide drill

A self-locking head-replaceable carbide drill, comprising a cutter head disposed at the upper end of a cutter shank. A cylinder is disposed at the lower part of the cutter head, a vertical cylinder holding slot or cylinder handle holding hole is disposed at the upper end of the cutter bar, at least two cutter head notches are disposed on the drilling body of the cutter head, and each cutter head notch is formed by intersecting a first and a second cutter head contact face. At least two upward protrusions disposed on the wall of the upper end of the cutter bar and have the same number as the cutter head notches. When assembling the cutter head and the cutter shank, the cutter head ridge edges and the inner surfaces of the protrusions are in non-contact fit, interference fit and non-interference fit in sequence.