Self-locking head-replaceable carbide drill mechanism
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Solution Overview
Problem
Existing head-replaceable carbide drills lack a self-locking function, making them difficult to manufacture and assemble/disassemble, and requiring complex screw fixation or interference fits, which complicates the drilling process.
Innovation Solution
A self-locking head-replaceable carbide drill design featuring a cutter head with intersecting notches and protrusions on the shank, allowing for non-contact, interference, and non-interference fits during assembly, ensuring a stable and secure connection without screws, facilitating easy assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screw fixation is used to connect cutter head and shank, then the connection is secure, but the assembly and disassembly process becomes complex and time-consuming
Solution Approach 1:
The patent removes the screw fixation mechanism from the connection system between cutter head and shank. Instead of using screws, the invention employs a direct interference fit where the cylindrical handle of the cutter head fits into a corresponding cavity in the shank, eliminating the need for additional fastening components and simplifying the assembly process.
Solution Approach 2:
The cutter head and shank are designed with self-locking geometric features - specifically, the cylindrical handle with diameter D1 fitting into the shank cavity, creating an interference fit that automatically locks the components together without requiring external fastening mechanisms. The self-service nature is evident in the automatic locking action upon insertion.
2Strength
If interference fit fixation is used between cutter head and shank, then the connection is firm, but the manufacturing precision requirements become strict and difficulty increases
Solution Approach 1:
The patent applies interference fit only at the critical interface between the cylindrical handle and shank cavity, while other parts of the components maintain standard tolerances. The local quality enhancement is concentrated at the connection zone where diameter D1 of the handle interferes with the shank cavity, providing strong connection without requiring high precision throughout the entire component manufacturing.
Solution Approach 2:
The invention uses specific dimensional parameters - the diameter D1 of the cylindrical handle is designed to be slightly larger than the diameter of the shank cavity, creating a controlled interference fit. By carefully selecting and controlling this specific parameter (the interference amount), the patent achieves firm connection while maintaining reasonable manufacturing precision requirements.
3Reliability
If conventional fixation methods are used, then the connection is stable, but the cutter head replacement process becomes time-consuming
Solution Approach 1:
The patent segments the drill structure into a reusable shank and replaceable cutter head portions. The cutter head with its cylindrical handle can be independently removed and replaced from the shank, allowing rapid replacement of worn cutting elements without replacing the entire drill tool, thus reducing replacement time while maintaining connection stability during operation.
Solution Approach 2:
The self-locking interference fit design allows the cutter head to be quickly inserted into and locked by the shank through a simple push-in motion, and equally quickly removed by applying axial force. This self-service mechanism eliminates the need for tools or complex procedures, enabling rapid cutter head replacement while ensuring stable connection during drilling operations.
Data Source
AI summary
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.