Electrostatic Clamping for Scale Detachment and Stability

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Solution Overview

Problem

Existing methods for holding a scale on a carrier, such as wringing and gluing, face challenges in achieving high stability and drift resistance while being detachable, as they can lead to peeling, non-reproducible length errors, and difficulty in replacing damaged scales.

Innovation Solution

The method employs electrostatic clamping using bipolar electrostatic attraction between a scale and a carrier, with electrodes on the carrier and a counter-electrode on the scale, allowing for a short force path and easy detachment, reducing the risk of peeling and length errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wringing is used to hold the scale on the carrier, then stability and drift resistance are improved, but the scale becomes difficult to detach and replace

Engineering Contradiction:
ImprovestabilityVSAvoiddetachability
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent changes the physical state of the attachment from permanent (wringing) to controllable and reversible by introducing electrostatic field parameters. By applying voltage to electrodes, the attachment force can be adjusted, allowing the scale to be firmly held during operation and easily detached when needed, resolving the contradiction between stability and detachability.

Inventive Principle:
Principle #35Parameter changes

2Strength

If gluing is used to hold the scale on the carrier, then attachment strength is improved, but shrinkage processes lead to non-reproducible length errors

Engineering Contradiction:
Improveattachment strengthVSAvoidlength accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the chemical-mechanical attachment system (gluing) with an electrostatic field-based system. This substitution eliminates the shrinkage processes inherent in adhesive curing, preventing the generation of internal stresses and non-reproducible length errors while maintaining strong attachment through electrostatic forces between charged electrodes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If a long force path through the entire thickness of the scale is used, then structural stability is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidposition measurement accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent segments the force transmission path by introducing intermediate support elements that provide localized support points. This segmentation allows the scale to maintain structural stability through distributed support while keeping the effective force path short at any given point, thereby preserving measurement precision by minimizing deformation across the scale thickness.

Inventive Principle:
Principle #1Segmentation

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

This approach provides a stable, drift-resistant, and detachable attachment that minimizes mechanical stresses and thermal expansion issues, ensuring high precision and ease of replacing defective scales, while maintaining accuracy and reducing manufacturing complexity.

Implementation Method 1

The method employs electrostatic clamping using bipolar electrostatic attraction between a scale and a carrier, with electrodes on the carrier and a counter-electrode on the scale

Methodology Applied
Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

A dielectric is provided between the electrodes

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP2002216B1Method for holding a scale on a carrier and arrangement having a carrier and a scale
Publication Date: 2015.07.08 DR JOHANNES HEIDENHAIN GMBH
  • EP2002216B1 patent drawingFigure 1~2
  • EP2002216B1 patent drawingFigure 3~4
  • EP2002216B1 patent drawingFigure 5~6

AI summary

According to the invention, a scale (1) having a measuring graduation (15) is reliably and releasably held on a carrier (2) by means of electrostatic clamping.