Conical Collet Asymmetry for Quick Tool Exchange

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Solution Overview

Problem

Existing devices for tool exchange in cutting tools require complex fastening mechanisms and large installation lengths, limiting quick and easy tool changes without special fastening elements.

Innovation Solution

A conical receiving opening with a non-round cross-section, such as a polygonal shape, for torque transmission, allowing the tool carrier insert to be fixed using the collet attachment thread, eliminating the need for special screws and reducing axial length, while maintaining high torque transmission capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a double conical collet with diametrically opposite retaining screws is used (DE 20 2007 013 371 U1), then torque transmission capability is improved, but device complexity and ease of operation deteriorate due to requiring lateral accessibility and high attachment effort

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidattachment effort
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies asymmetry by using a single-sided attachment mechanism where the retaining screw is accessible from one side only, eliminating the need for lateral accessibility required by diametrically opposite screws. The asymmetric design allows the screw to engage a corresponding asymmetric feature on the collet, providing secure attachment while simplifying the fastening operation to a single-sided action.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent extracts the torque transmission function from a complex multi-screw system and concentrates it into a single retaining screw mechanism. By removing the need for multiple diametrically opposite screws and their associated lateral accessibility requirements, the design achieves adequate torque transmission with reduced complexity and improved ease of operation.

Inventive Principle:
Principle #2Taking out (Extraction)

2Strength

If retaining screws diametrically opposite one another are used, then torque transmission is improved, but ease of operation worsens due to requiring lateral accessibility

Engineering Contradiction:
Improvetorque transmissionVSAvoidlateral accessibility requirement
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent replaces the symmetric diametrically opposite screw arrangement with an asymmetric single-sided screw configuration. The retaining screw engages with an asymmetric feature on the collet, allowing attachment from one side only and eliminating the lateral accessibility requirement while maintaining adequate torque transmission capability.

Inventive Principle:
Principle #4Asymmetry

3Manufacturing precision

If a form-fitting torque transmission is arranged on the front edge of the conical receiving opening, then torque transmission precision is improved, but reliability worsens due to increased risk of contamination and damage

Engineering Contradiction:
Improveform-fitting precisionVSAvoidcontamination and damage risk
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent inverts the conventional approach by placing the form-fitting torque transmission feature not on the front edge of the conical receiving opening, but rather on the collet itself through an asymmetric engagement feature. This reversal moves the precision interface away from the contamination-prone front edge location to a more protected position, maintaining form-fitting precision while improving reliability.

Inventive Principle:
Principle #13The other way round (Inversion)

4Strength

If special fastening elements are used for tool carrier insert, then torque transmission is improved, but device complexity worsens

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidnumber of special fastening elements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the retaining screw mechanism to serve multiple functions: it provides both the attachment function and the torque transmission function. The asymmetric feature on the collet that engages with the retaining screw serves as both the positioning element and the torque transmission interface, eliminating the need for separate special fastening elements and reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2292358B1Device with a holder for a cutting tool
Publication Date: 2012.11.28 HEIMATEC
  • EP2292358B1 patent drawingFigure 1
  • EP2292358B1 patent drawingFigure 2~6
  • EP2292358B1 patent drawingFigure 7~10

AI summary

The device (1) has a chuck fastening and a chuck, which is provided for fixing the tool. The chuck is formed in a conical support opening (5). A cone section of a tool carrier insert is arranged in the conical support opening for the chuck such that the cone section is fixed in functional position with the help of a thread (8) of the chuck fastening.