Self-Clamping Cutting Tool Coupling with Differential Radii

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Solution Overview

Problem

Existing cutting tools with self-clamping mechanisms suffer from reduced elasticity and coupling strength due to repeated assembly and disassembly, leading to eventual failure in maintaining a secure coaxial connection between the cutting portion and tool body.

Innovation Solution

A cutting tool design featuring a male and female coupling member with specific diameter relationships and torque transmission elements, allowing for self-clamping through rotational alignment and friction, maintaining coaxiality and coupling strength without the need for heat expansion, and featuring piloting members for alignment and guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the cutting portion and tool body are connected through repeated assembly and disassembly, then the cutting tool can be reused multiple times, but the elasticity of the projections is reduced and the coupling strength is weakened

Engineering Contradiction:
ImprovereusabilityVSAvoidcoupling strength
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the coupling mechanism by providing support surfaces at different radial distances from the longitudinal axis (first support surface at radius R1, second support surface at radius R2 where R1 ≠ R2). This creates differential engagement that maintains elastic properties over repeated assemblies while preserving coupling strength through the asymmetric radial distribution of contact surfaces.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the projections are made elastic to enable self-clamping, then the coupling can be easily assembled and disassembled, but repeated use reduces the elasticity until coupling fails

Engineering Contradiction:
Improveself-clamping capabilityVSAvoidservice life
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The coupling mechanism is segmented into distinct functional elements: piloting members for alignment, multiple support surfaces at different radii for differential engagement, and wall recesses for elastic deformation. This segmentation allows each element to perform its specific function optimally while distributing wear across multiple contact points, extending service life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extends the coupling interaction from a single-plane engagement to a multi-radial engagement by positioning support surfaces at different radial distances (R1 and R2) from the longitudinal axis. This dimensional distribution creates a more robust coupling that maintains elastic properties through repeated assemblies by engaging multiple radial zones simultaneously.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Strength

If the support surfaces are positioned at different radial distances, then the coupling strength is maintained through differential engagement, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecoupling strengthVSAvoidradial positioning accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The piloting members are positioned at the extremities of the male coupling member to perform preliminary alignment before the support surfaces engage. This preliminary action establishes the correct radial positioning and coaxial alignment, thereby reducing the actual manufacturing precision requirements for the support surfaces themselves while maintaining coupling strength.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a robust and long-lasting self-clamping mechanism that maintains coupling strength and coaxial alignment, reducing wear and extending the tool's operational life by utilizing frictional forces and a continuous bore wall for enhanced elasticity and strength.

Implementation Method 1

maintaining coupling strength and coaxial alignment, reducing wear and extending the tool's operational life by utilizing frictional forces

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

featuring a continuous bore wall for enhanced elasticity and strength

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2667993B1Cutting tool
Publication Date: 2018.05.09 ISCAR LTD
  • EP2667993B1 patent drawingFigure 1
  • EP2667993B1 patent drawingFigure 2~4
  • EP2667993B1 patent drawingFigure 5~8

AI summary

A cutting tool (10) having a cutting head (12) removably secured to a shank (14) by frictional forces maintained between a male coupling member (28) located in a female coupling member (26). Support surfaces (32) of the male coupling (28) member engage support walls (54) of the female coupling member (26). The support surfaces (32) lie on a common cylinder having a larger diameter than a common cylinder on which the support walls (54) lie. The support walls (54) are located on a circumferentially continuous bore wall of the female coupling member (26).