Piezoelectric Switch Contact Mounting for Small-Force Detection

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Solution Overview

Problem

Existing electrical device switching systems lack sensitivity in detecting small forces and contact pressures, particularly in applications like touch-sensitive hotplates, where precise detection of operator interactions is crucial.

Innovation Solution

A compact electrical device switching device featuring a planar piezoelectric sensor element mounted on a bent, resilient bearing unit that bends upon contact, allowing for high sensitivity and rapid response to mechanical stress, with an optional vibration unit for enhanced precision and an amplifier circuit for evaluating small bending paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a piezoelectric sensor element is mounted on a rigid bearing unit, then the device structure is simple and stable, but the sensitivity to small contact forces is insufficient

Engineering Contradiction:
Improvedetection sensitivityVSAvoidbearing unit structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The bearing unit is designed as a resilient element that can dynamically bend in response to contact forces, transforming the rigid structure into a dynamic one that adapts to applied loads, thereby enhancing sensitivity without requiring complex additional components

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bearing unit's mechanical properties are changed by introducing resilience, allowing it to deform under small forces and amplify the sensor element's response, thus improving measurement precision through parameter modification rather than structural complexity

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the sensor element is made thicker for structural stability, then manufacturing is easier, but the bending sensitivity decreases

Engineering Contradiction:
Improvebending sensitivityVSAvoidsensor element fabrication
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Instead of increasing thickness (one dimension) for stability, the solution moves to optimizing the planar dimensions and mounting configuration (other dimensions), allowing thin sensor elements to achieve both stability and sensitivity through proper geometric design and resilient support

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If the bearing unit is designed to bend easily for high sensitivity, then detection precision improves, but the device becomes more complex

Engineering Contradiction:
Improvecontact force detectionVSAvoidbearing unit design
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The bearing unit is designed as a flexible resilient element that naturally bends under load, using the inherent properties of flexible materials to achieve high sensitivity without complex mechanical mechanisms, thus improving detection while maintaining design simplicity

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution enables precise detection of small contact forces and rapid activation of electrical devices, particularly suitable for touch-sensitive applications like hotplates, with improved sensitivity and response time, allowing for efficient and safe operation.

Implementation Method 1

at least one piezoelectric sensor element which is provided to detect a touch of the contact area

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2210341B1Electric appliance switching device
Publication Date: 2020.02.26 BSH HAUSGERATE GMBH
  • EP2210341B1 patent drawingFigure 1
  • EP2210341B1 patent drawingFigure 2
  • EP2210341B1 patent drawingFigure 3~4

AI summary

The invention relates to an electric appliance switching device having a contact body (34) forming a contact region (30, 32) for contacting in an electric appliance operation process, at least one piezoelectric sensor element (36, 38) that is provided in order to detect contact of the contact region (30, 32), and a storage unit (44; 44a-g) for storing the sensor element. In order to achieve a high degree of sensitivity to the piezoelectric sensor element in a sensing process, the invention proposes that the storage unit (44; 44a-g) have a storage means (46; 46a-g) provided for the purpose of causing the sensor element (36, 38) to bend based on contact to the contact region (30, 32).