Rotary Cutting Tool Axial Locking via Parallel Stop Shoulders
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Solution Overview
Problem
Existing drill tools with conical gripping surfaces require high tolerance and are complex to manufacture, making them challenging to achieve effectively through mechanical machining.
Innovation Solution
The use of parallel stop surfaces and shoulders on the coupling legs and cutting head, which limit axial movement and prevent displacement without the need for conical sections, simplifying manufacturing and reducing tolerance requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conical gripping surfaces are used to achieve positive locking between tool body and cutting head, then axial displacement prevention is improved, but manufacturing complexity and tolerance requirements increase
Solution Approach 1:
Instead of using conical surfaces that widen toward the rear end to achieve positive locking, the patent inverts the approach by using shoulders that extend outward from parallel stop surfaces. The shoulders protrude from the stop surfaces of the coupling legs and engage with corresponding shoulders on the cutting head, creating axial locking through a inverted geometric configuration that is simpler to manufacture
Solution Approach 2:
The patent changes the geometric parameters of the gripping surfaces from conical (with specific taper angles) to parallel surfaces with perpendicular shoulders. This parameter change transforms the locking mechanism from one requiring precise angular tolerances to one that can be achieved with standard orthogonal machining, significantly reducing manufacturing complexity while maintaining reliable axial locking
2Reliability
If conical gripping surfaces are used to prevent axial displacement, then locking function is improved, but tolerance requirements increase
Solution Approach 1:
The patent inverts the conventional conical locking approach by using shoulders extending from parallel stop surfaces. This inversion replaces the need for precise conical surface intersections with simple shoulder-to-shoulder engagement, dramatically reducing tolerance requirements while maintaining effective axial locking
Solution Approach 2:
By changing the geometric parameters from conical surfaces requiring precise angle tolerances to parallel surfaces with 90-degree shoulders, the patent reduces the critical tolerance zones. The parallel stop surfaces and perpendicular shoulders can be manufactured with standard tolerances, eliminating the need for high-precision conical surface machining
Data Source
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AI summary
The invention relates to a tool for rotary cutting machining, comprising a tool body (10) and a replaceable cutting head (30) de- tachably attachable to the tool body. At its front end, the tool body is provided with two coupling legs (13a, 13b) projecting in axial direction. The respective coupling leg is provided with a stop surface (16a, 16b) for transferring torque from the tool body to the cutting head, which stop surface is designed for abutment against a corresponding stop surface (36a, 36b) of the cutting head. The respective coupling leg is provided with a shoulder (26a, 26b) protruding from the stop surface of the coupling leg. The cutting head is provided with two shoulders (46a, 46b) facing the front end of the cutting head and arranged on opposite sides of the centre axis of the cutting head, which shoulders border on a respective one of said stop surfaces of the cutting head and are arranged to extend in under a respective one of said shoulders of the coupling legs of the tool body when the cutting head is attached to the tool body, so as to thereby prevent the cutting head from being displaced in axial direction away from the tool body. The invention also relates to a tool body and a cutting head included in such a tool.