Multilayer Load Cell Assembly for Automated Strain Sensing

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Solution Overview

Problem

Existing strain gauges and load sensors are not suitable for automated application and installation in industrial processes, lacking mechanical stability and requiring manual, time-consuming methods that are prone to errors and inefficiencies.

Innovation Solution

A mechanically stabilized, deformable multilayer load cell with a fastening intermediary body, carrier substrate, and piezoresistive elements, allowing for automated mounting and integration into industrial processes, featuring a durable electrical connection and protective lacquer coat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If foil strain gauges are directly applied to constructive parts by adhesive, then strain measurement capability is achieved, but automated application and connection becomes impossible

Engineering Contradiction:
Improvestrain measurement capabilityVSAvoidautomated application and connection
Core Design Contradiction:
Measurement precisionVSExtent of automation

Solution Approach 1:

The load cell is divided into separate functional layers (fastening intermediary body, carrier substrate, piezoresistive elements, wiring, protective coating) that can be manufactured independently and assembled automatically, eliminating the need for manual adhesive application while maintaining measurement precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A fastening intermediary body is introduced as an intermediary component between the constructive part and the carrier substrate, enabling automated mechanical fastening while preserving the strain transfer function previously achieved through adhesive bonding

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If semiconductor strain gauges are integrated in ceramic substrates with temperature sensors, then measurement accuracy is improved, but device complexity and installation sensitivity increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The carrier substrate serves multiple functions: it provides mechanical support, transfers strain to piezoresistive elements, and integrates temperature compensation capabilities, eliminating the need for separate temperature sensors and reducing overall device complexity

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

Solution Approach 2:

The piezoresistive elements and temperature compensation elements are integrated into a single carrier substrate assembly, reducing the number of separate components and simplifying installation while maintaining measurement accuracy

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If mechanical bridge construction is used for mounting strain gauges, then mounting stability is achieved, but installation becomes expensive and sensitive

Engineering Contradiction:
Improvemounting stabilityVSAvoidinstallation cost and sensitivity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The mounting function is separated from the sensing function by introducing a dedicated fastening intermediary body, allowing the sensing elements to be mounted using simple, automated processes while the fastening body provides the required mechanical stability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Complex mechanical bridge constructions are replaced by a simplified fastening intermediary body with standardized fastening structures, enabling automated installation while maintaining mounting stability through proper mechanical attachment

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

4Strength

If reactive viscose adhesive is used to secure strain gauges, then bonding is achieved, but installation time and handling effort increase significantly

Engineering Contradiction:
Improvebonding strengthVSAvoidinstallation time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

Adhesive bonding is replaced by mechanical fastening using the fastening intermediary body, allowing instantaneous attachment without waiting for adhesive curing and eliminating the need for time-consuming pressure application and thickness reduction steps

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

Solution Approach 2:

The fastening intermediary body is pre-configured with fastening structures that enable immediate mechanical attachment, eliminating the time required for adhesive application, curing, and pressure application that characterizes reactive viscose adhesive methods

Inventive Principle:
Principle #10Preliminary action

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

Enables reliable, automated installation and operation of load sensors in harsh environments, reducing sensitivity to handling and ensuring accurate measurement of mechanical deformation with minimal energy consumption.

Implementation Method 1

a piezoresistive element 42 which is integrated in an electric circuit 41 and is arranged on the carrier substrate 40

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP4545925B1Mechanically stabilized, deformable multilayer load cell, a method of manufacture thereof, and a constructive part in combination therewith
Publication Date: 2025.12.10 BOLLHOFF OTALU SA
  • EP4545925B1 patent drawingFigure 1~2
  • EP4545925B1 patent drawingFigure 3~4
  • EP4545925B1 patent drawingFigure 5

AI summary

A mechanically stabilized, deformable multilayer load cell adapted to be fastened to a body so that by means of a deformation of the body, a mechanical force acting upon the body is determinable, and which comprises the following features: a fastening intermediary body having a fastening structure with which the load cell is fastenable, preferably mechanically fastenable, to a component via the fastening intermediary body, a carrier substrate onto which at least one piezoresistive element is applied in an electric circuit, the carrier substrate has the form of a plate, preferably a rectangular plate, and is fastened to the fastening intermediary body by means of an adhesive layer.