Fiber Composite Spring Arrangement for Machine Tool Clamping

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Solution Overview

Problem

Existing clamping devices in machine tools, particularly those using disk spring assemblies, have high mass, limited service life, and require significant assembly effort, making them inefficient and prone to corrosion.

Innovation Solution

A clamping device utilizing a spring arrangement made of fiber composite materials, designed as a compact, lightweight buckling bar spring with adjustable properties, which is easy to manufacture and install, and can be actuated hydraulically, pneumatically, or electrically for simplified operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If disk spring assemblies are used to generate clamping force, then the required clamping force is achieved, but the mass increases and service life is limited

Engineering Contradiction:
Improveclamping forceVSAvoidmass of spring arrangement
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by replacing traditional metal disk springs with spring elements made from fiber-reinforced plastics (FRP) or carbon-fiber-reinforced plastics (CFRP). These composite materials provide the necessary elastic modulus and strength to generate the required clamping force while significantly reducing the mass compared to conventional metal spring assemblies.

Inventive Principle:
Principle #40Composite materials

2Force

If disk spring assemblies are used to generate clamping force, then the required clamping force is achieved, but the assembly effort increases

Engineering Contradiction:
Improveclamping forceVSAvoidassembly effort
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The spring arrangement is segmented into multiple individual spring elements that can be independently manufactured and then assembled. Each spring element is a separate component that can be produced using standardized manufacturing processes, and the modular design allows for easier assembly and replacement compared to a monolithic disk spring assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The use of composite materials enables simplified manufacturing processes for the spring elements, as FRP and CFRP components can be manufactured through molding and curing processes that integrate multiple operations into fewer steps, reducing overall assembly effort.

Inventive Principle:
Principle #40Composite materials

3Force

If traditional spring arrangements are used, then clamping force is generated, but corrosion resistance is poor

Engineering Contradiction:
Improveclamping forceVSAvoidcorrosion resistance
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent employs fiber-reinforced plastics and carbon-fiber-reinforced plastics as spring materials, which inherently possess excellent corrosion resistance. These composite materials do not rust or degrade when exposed to moisture, chemicals, or harsh environmental conditions, thereby significantly improving the reliability and service life of the clamping device compared to traditional metal springs.

Inventive Principle:
Principle #40Composite materials

4Force

If disk spring assemblies with large number of springs are used, then the required clamping force is achieved, but the service life is limited

Engineering Contradiction:
Improveclamping forceVSAvoidservice life
Core Design Contradiction:
ForceVSDuration of action of stationary object

Solution Approach 1:

The use of high-strength composite materials like carbon-fiber-reinforced plastics provides superior fatigue resistance and structural integrity compared to conventional metal disk springs. This extends the service life of the spring arrangement by preventing material degradation, fatigue failure, and corrosion over extended operational periods.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a large number of simple, individually replaceable spring elements made from durable composite materials. While each individual element is simple and potentially replaceable, the collective arrangement provides extended service life through redundancy and ease of replacement, effectively creating a durable yet maintainable system.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 fiber composite spring arrangement provides a durable, corrosion-resistant clamping solution with extended service life and reduced assembly effort, offering improved performance and reliability in machine tool applications.

Implementation Method 1

the spring arrangement (17) has a plurality of spring elements (27) made of a fiber composite material

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the spring arrangement can be designed, for example, as a buckling bar spring with a plurality of bar-shaped spring elements spaced apart from one another in the circumferential direction

Methodology Applied
Scientific EffectBuckling:

Data Source

PatentEP3028795B1Clamping device
Publication Date: 2017.06.14 OTT JAKOB & SPANNTECHN
  • EP3028795B1 patent drawingFigure 1
  • EP3028795B1 patent drawingFigure 2
  • EP3028795B1 patent drawingFigure 3~4

AI summary

The invention relates to a clamping device (1) for clamping a workpiece or a tool or tool holder (3) on a machine part (2) of a machine tool, comprising an axially (4) displaceable drawbar (7), a clamping set (11) movable via the drawbar (7) between a clamping position and a release position, a spring assembly (17) associated with the drawbar (7) for generating the clamping or pull-in force of the clamping set (11), and a release unit (23) by which the clamping set (11) can be moved via the drawbar (7) against the force of the spring assembly (17) into the release position. According to the invention, the spring assembly (17) comprises several spring elements (27) made of a fiber composite material.