Scanning Head Probe Element Force Limiting Design

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Solution Overview

Problem

Existing probe systems using highly sensitive sensors are prone to damage due to excessive pressure loads and overload during large deflections, leading to inconsistent and unreliable probing behavior.

Innovation Solution

A probe design featuring a probe element with a first contact point for direct or indirect pressure transmission to sensors and a second contact point for supporting the probe element, limiting pressure forces on sensors, with a configuration that includes a transmission element and a mounting element to ensure uniform switching characteristics and protect sensitive sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If highly sensitive sensors are used to achieve exact probing behavior, then measurement precision is improved, but reliability deteriorates due to sensor overload and destruction during large deflections

Engineering Contradiction:
Improveprobing precisionVSAvoidsensor robustness
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A transmission element is introduced as an intermediary between the probe element and the sensor. This transmission element transfers the probing force to the sensor while limiting the maximum force transmitted, thereby protecting the highly sensitive sensor from overload during large deflections while maintaining measurement precision during normal operation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The probe element is designed with a stop position that prevents excessive deflection before the sensor can be overloaded. This mechanical limitation acts as a preventive measure, cushioning the sensor against harmful forces before they can cause damage, thus maintaining both sensor reliability and probing precision

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If the probe element is made deflectable to enable scanning operation, then ease of operation is improved, but harmful factors increase due to excessive pressure loads on sensors

Engineering Contradiction:
Improvescanning capabilityVSAvoidpressure load on sensors
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The transmission element serves as a mediator that allows the probe element to be highly deflectable for easy scanning operation while simultaneously limiting the pressure load transmitted to the sensor, thus enabling ease of operation without introducing harmful factors

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The probe element is designed to be dynamically deflectable during scanning operations, allowing free movement for ease of operation. The transmission element dynamically adapts the force transmission, being flexible during normal scanning but limiting excessive forces, thus enabling dynamic operation without harmful pressure loads

Inventive Principle:
Principle #15Dynamics

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 design allows for precise and robust probing with highly sensitive sensors, reducing wear and tear and ensuring consistent switching behavior, even under excessive deflection, by limiting pressure forces and maintaining sensor integrity.

Implementation Method 1

sensors (5), each with a pressure-sensitive surface (5.1), by which electrical signals can be generated when pressure forces with a directional component orthogonal to the pressure-sensitive surface (5.1) are applied

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP1762817B1Scanning head
Publication Date: 2009.03.18 DR JOHANNES HEIDENHAIN GMBH
  • EP1762817B1 patent drawingFigure 1
  • EP1762817B1 patent drawingFigure 2~3
  • EP1762817B1 patent drawingFigure 4~5

AI summary

The head has a probe element delectable relative to an annular element (9), where the probe element includes a longitudinal axis, and two contact points. Pressure-sensitive piezoresistive sensors (5) are stationary with respect to the annular element, where each sensor includes a pressure-sensitive surface. One sensor is adapted to produce electrical signals when a pressure force acts that has a directional component orthogonal to the pressure-sensitive surface. The probe element is arranged such that pressure forces that are able to be introduced into the sensors are limited in a stop position.