Collet With Elastic Joints For High Speed Clamping

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Solution Overview

Problem

Existing collets face challenges in reliably coupling tool holders at high speeds due to insufficient clamping force and stability, especially in rotational applications.

Innovation Solution

A collet composed of multiple clamping segments connected by elastic joints made of plastic, designed as elongated fastening webs, which provide a restoring force without external springs, ensuring reliable clamping and easy manufacturability through radial alignment and geometric shape optimization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If additional restoring elements such as garter springs are added to generate restoring force, then the restoring force increases, but the device complexity increases

Engineering Contradiction:
Improverestoring forceVSAvoiddevice complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent merges the restoring force generation function into the joint structure itself by designing the joint with an asymmetric cross-section (different thicknesses in different radial directions). This eliminates the need for separate restoring elements like garter springs, as the joint's own geometric asymmetry provides the necessary restoring force when deflecting from the neutral position.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The joint structure serves itself by generating the restoring force through its own geometric design rather than requiring external restoring elements. The asymmetric thickness distribution in the joint creates an inherent mechanical advantage that automatically generates restoring force during deflection, making the system self-sufficient.

Inventive Principle:
Principle #25Self-service

2Reliability

If the collet is designed with multiple clamping segments and elastic joints, then the clamping force and stability improve, but the manufacturing complexity increases

Engineering Contradiction:
Improveclamping stabilityVSAvoidmanufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The collet is divided into multiple clamping segments connected by elastic joints, allowing independent deflection of each segment while maintaining overall structural integrity. This segmentation enables the collet to adapt to slight variations in tool holder geometry and maintains reliable clamping force distribution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The joint's asymmetric cross-sectional parameters (different thicknesses in different directions) are optimized to provide the desired restoring force characteristics. By carefully selecting the thickness parameters, the design achieves both high clamping stability and manufacturability through standard plastic molding processes.

Inventive Principle:
Principle #35Parameter changes

3Force

If the fastening webs are made with larger volume to increase restoring force, then the clamping force increases, but the collet volume increases

Engineering Contradiction:
Improveclamping forceVSAvoidcollet volume
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The joint structure concentrates material volume strategically in the asymmetric thickness regions where it is most effective for generating restoring force. Rather than uniformly increasing the entire joint volume, the design places material only where needed - with greater thickness in specific radial directions - thereby achieving high clamping force with minimal overall volume increase.

Inventive Principle:
Principle #3Local quality

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 achieves a high clamping force and stability, allowing reliable coupling of tool holders at high speeds with a simple design and economic manufacturability, ensuring the clamping segments automatically return to their initial position after deflection.

Implementation Method 1

The joints are made of an elastic material and are firmly connected to the clamping segments... The spring properties of each individual clamping element are generated or defined at the rear end section of the collet by the volume of the fastening webs

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP1982782B1Collet
Publication Date: 2011.09.14 REINAUER JOSEF
  • EP1982782B1 patent drawingFigure 1a~2
  • EP1982782B1 patent drawingFigure 3~5
  • EP1982782B1 patent drawingFigure 6~7

AI summary

Clamping tongs (1) comprise clamping segments (2) and single hinges (3). Preferred Features: The radial deflection of the clamping segments is carried out below the hinges on the rear part of the tongs. The hinges are individually connected to the clamping segments. The hinges are made from am elastic material.