Capacitive Proximity Sensor with Adjustable Switching Point

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Solution Overview

Problem

Existing boarding aids for vehicles, particularly public transport, face issues with load detection accuracy due to manufacturing tolerances, leading to complex and time-consuming adjustment processes for inductive proximity sensors, which complicates the structure and maintenance.

Innovation Solution

A capacitive proximity sensor with an individually adjustable switching point is used, allowing for software-based adjustment of the trigger value without physical changes to the sensor or detection object, simplifying the structure and reducing costs by accepting manufacturing tolerances as the actual state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inductive proximity sensors are used for load detection, then detection reliability is improved, but device complexity increases due to adjustment mechanisms

Engineering Contradiction:

Improvedetection reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical adjustment system (adjustment screw, spring-loaded detection object) with a software-based solution. The capacitive proximity sensor's switching point is adjusted electronically through programmable thresholds rather than physical repositioning, eliminating mechanical complexity while maintaining detection reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection principle from inductive to capacitive sensing, which allows for software-based threshold adjustment. The capacitive sensor detects changes in electrical field capacitance caused by load, enabling flexible electronic calibration without mechanical adjustment components.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If physical adjustment of detection object position is performed, then manufacturing precision is improved, but ease of manufacture deteriorates

Engineering Contradiction:

Improvetrigger position precisionVSAvoidease of manufacture

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent eliminates mechanical adjustment components (adjustment screws, spring-loaded mechanisms) by using a capacitive sensor with software-based threshold calibration. This allows precise trigger position setting through electronic parameters rather than physical assembly adjustments, greatly simplifying manufacturing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs calibration in advance by storing reference capacitance values corresponding to known load states (empty, partially loaded, fully loaded) in the control unit. This preliminary calibration eliminates the need for manual adjustment during assembly or maintenance, improving both manufacturing ease and operational reliability.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If adjustment screw and spring-loaded detection object are used, then adaptability is improved, but ease of repair deteriorates

Engineering Contradiction:

ImproveadjustabilityVSAvoidease of repair

Core Design Contradiction:

Adaptability or versatilityVSEase of repair

Solution Approach 1:

The patent replaces mechanical adjustment components with electronic software configuration. The capacitive sensor's switching threshold is adjusted through programmable parameters stored in the control unit, eliminating adjustment screws and spring-loaded mechanisms that require disassembly and mechanical skill to repair.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-calibration by automatically comparing measured capacitance values against stored reference values for different load states. This self-service calibration eliminates the need for manual intervention during maintenance, making the system easier to repair and maintain.

Inventive Principle:

Principle #25Self-service

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 simplifies the structure, reduces costs, and allows for easy maintenance by eliminating the need for physical adjustments, enabling quick and reliable setting of the trigger value, even during operation, through software adjustments.

Implementation Method 1

The proximity sensor is formed by a capacitive proximity sensor with an individually adjustable switching point

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4265503A1Climbing aid with proximity switch having adjustable switching point

Publication Date: 2023.10.25 BODE - DIE TUR GMBH

Figure 1~2
Figure 3~4

AI summary

The invention relates to a boarding aid (20) for a vehicle, in particular for a public transport vehicle. This aid comprises a tread (24) and a measuring device (28) for detecting a load on the tread (24), wherein the measuring device (28) is formed by a proximity sensor (30) and a detection object (32). The distance between the proximity sensor (30) and the detection object (32) changes due to the load on the tread (24), and the detection object can be detected by the proximity sensor (30) from a certain distance. The proximity sensor (30) is a capacitive proximity sensor (30) with an individually adjustable switching point, wherein the proximity sensor (30) is programmable such that its trigger value can be set in relation to the position of the detection object (32) at a definable trigger position.