Transducer Plate for Multi-Leaf Spring Deflection Measurement

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Solution Overview

Problem

Existing load measuring devices in multi-leaf spring arrangements are susceptible to contamination and damage, leading to inaccurate data collection, and often require complex constructions and extensive control efforts.

Innovation Solution

A transducer plate with a multifunctional bending bar design, featuring clamping ridges, stiffening webs, and a measuring sector with a strain gauge, is integrated into the multi-leaf spring arrangement to measure leaf spring deflections while being robust and resistant to contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a thin film transducer is directly mounted within the stack of leaf springs, then the sensitivity of the force sensor is improved, but the susceptibility to damage and contamination increases leading to failure of collected data

Engineering Contradiction:
Improvesensitivity of force sensorVSAvoidsusceptibility to damage and contamination
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary protective structure (housing or enclosure) that separates the thin film transducer from the harsh environment within the leaf spring stack. This mediator protects the sensitive transducer elements from direct exposure to contamination and mechanical damage while still allowing the transducer to function and measure forces accurately.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs protective housings or enclosures that act as flexible barriers around the thin film transducer. These protective shells allow the sensitive thin film elements to be shielded from damage and contamination while maintaining the necessary mechanical coupling for force measurement.

Inventive Principle:
Principle #30Flexible shells and thin films

2Strength

If a bar-like construction bearing the sensor is used, then the stiffness with respect to bending forces is improved, but the ability to follow leaf spring deflections deteriorates leading to distorted measurement results

Engineering Contradiction:
Improvestiffness of sensor constructionVSAvoidaccuracy of deflection measurement
Core Design Contradiction:
StrengthVSMeasurement precision

Solution Approach 1:

The patent divides the sensor construction into segmented parts: a stiff supporting structure for mounting and a separate, more flexible measurement component. This segmentation allows the stiff bar-like construction to provide structural support while the flexible portion can follow leaf spring deflections accurately without distortion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different mechanical properties to different parts of the sensor construction. The mounting structure uses high stiffness materials and designs for structural stability, while the measurement portion uses more flexible materials or geometries that can accurately track leaf spring deflections. This local differentiation of mechanical properties resolves the contradiction between overall stiffness and deflection following capability.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If multiple strain gauges and sophisticated beam construction are used, then the measurement capability is improved, but the device complexity and control efforts increase

Engineering Contradiction:
Improveload measurement capabilityVSAvoidcomplexity of beam construction and control
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates unnecessary components from complex beam constructions and multi-strain gauge arrangements. By removing redundant elements and focusing on a simplified transducer design, the patent achieves adequate measurement precision with significantly reduced device complexity and control requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs simple, readily manufacturable transducer components that can be easily replaced if needed, rather than investing in complex, expensive beam constructions. This approach prioritizes functional adequacy over measurement sophistication, reducing both device complexity and maintenance burden.

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 transducer plate effectively measures leaf spring deflections with high accuracy, is resistant to contamination, and requires less complex control efforts, providing reliable vehicle load data.

Implementation Method 1

a measuring sector (60) centrally arranged in the bending section (22) between the clamping ridges (30) and the stiffening webs (40), respectively, wherein a wire strain gauge (70) can be disposed on the measuring sector (60) for deflection evaluation

Methodology Applied
Scientific EffectStrain gauge: Piezoresistive Effect

Data Source

PatentEP4239298B1Transducer plate for a multi-leaf spring assembly
Publication Date: 2025.04.30 BOLLHOFF OTALU SA
  • EP4239298B1 patent drawingFigure 1~2
  • EP4239298B1 patent drawingFigure 3~4
  • EP4239298B1 patent drawingFigure 5

AI summary

A transducer plate 20 adapted to be mounted in a multi-leaf spring arrangement 10 so that a deflection of an adjacent leaf spring 12 can be measured, said transducer plate 20 comprises the following features: at least two oppositely arranged clamping ridges 30 which are spaced from each other by a bending section 22, at least two stiffening webs 40 oppositely arranged to each other and each bridging a distance between the opposed clamping ridges 30 wherein the at least two stiffening webs 40 are spaced from each other by the bending section 22, and mechanically decoupled from the bending section 22 by an intermediate separation segment 50 formed as a recess or an opening, and a measuring sector 60 centrally arranged in the bending section 22 between the clamping ridges 30 and the stiffening webs 40, respectively, wherein a wire strain gauge can be disposed on the measuring sector 60 for deflection evaluation.