Tiller Arm Position Sensor Radial Orientation

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Solution Overview

Problem

Existing devices for detecting the vertical tiller position of industrial trucks are not precise and reproducible due to wear and tear issues with contact sensors and sensitivity limitations in non-contact sensors, particularly because of axial bearing play affecting the distance between the sensor and counterpart.

Innovation Solution

A device with a drawbar articulated on a bracket that pivots about a horizontal axis, using a contactless sensor with an active surface normal arranged radially to the pivot axis, minimizing the influence of axial bearing play and ensuring precise detection through inductive or capacitive sensing, with a counterpart designed to maintain a consistent distance for accurate signal generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a contact sensor is used for detecting the vertical tiller position, then the device can be constructed simply and inexpensively, but the sensor is subject to wear and tear leading to failure and high repair costs

Engineering Contradiction:
Improveconstruction simplicityVSAvoidsensor durability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the mechanical contact sensor with a non-contact sensor that detects the vertical tiller position through electromagnetic or optical fields. The sensor detects the position of a counterpart (such as a magnet or reflective surface) attached to the tiller without any physical contact, thereby eliminating wear and tear while maintaining detection functionality. This substitution resolves the contradiction by sacrificing some construction simplicity for significantly improved reliability.

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

2Reliability

If a non-contact sensor is used for detecting the vertical tiller position, then the sensor is less sensitive to interference and wear, but the detection precision is limited due to the gap between the sensor and counterpart

Engineering Contradiction:
Improvesensor durabilityVSAvoidposition detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent optimizes the gap distance between the non-contact sensor and its counterpart to a specific range that balances reliability and precision. By carefully controlling this parameter (the distance), the system achieves both wear-free operation and sufficient detection accuracy for the intended application. This parameter optimization resolves the contradiction by finding the optimal operating point rather than treating it as a binary choice.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the surface normal of the active sensor surface is arranged radially with respect to the horizontal axis, then the accuracy and reproducibility of detection is enhanced, but the device complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidsensor arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs an asymmetric arrangement where the surface normal of the active sensor surface is oriented radially with respect to the horizontal axis of the tiller bracket. This asymmetric configuration optimizes the detection geometry to minimize the influence of axial bearing play, thereby improving measurement precision. The increased complexity is justified by the significant improvement in detection accuracy and reproducibility.

Inventive Principle:
Principle #4Asymmetry

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 configuration enhances the accuracy and reproducibility of detecting the vertical tiller position, reducing dependency on bearing wear and allowing for reliable activation/deactivation of the traction drive based on precise position detection.

Implementation Method 1

the sensor has an active sensor surface on which the counterpart or on the counterpart is guided past when the drawbar moves relative to the drawbar bracket

Methodology Applied
Scientific EffectInductive sensing: Electromagnetic Induction

Implementation Method 2

using a contactless sensor with an active surface normal arranged radially to the pivot axis, minimizing the influence of axial bearing play and ensuring precise detection through inductive or capacitive sensing

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentEP2284061B1Device for detecting the vertical position of a tiller arm of an tiller truck
Publication Date: 2013.04.17 JUNGHEINRICH AG
  • EP2284061B1 patent drawingFigure 1~3
  • EP2284061B1 patent drawingFigure 4~5
  • EP2284061B1 patent drawingFigure 6~7

AI summary

The device has a shaft that is pivoted opposite to a shaft support (28) around a horizontal axis. A sensor (34) is provided for contact-free recording of the position of a counter piece (42). A surface normal of an active sensor surface (44) is arranged with respect to the horizontal axis in a radial manner. An independent claim is also included for an industrial truck with wheels.