Digital Magnetic Sensor Fork Positioning for Industrial Trucks

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Solution Overview

Problem

Industrial trucks with side shift capability face challenges in accurately determining the lateral position of forks, especially during centering, due to external influences on analog sensors, leading to potential collisions with support legs during vertical displacement.

Innovation Solution

The use of digital magnetic sensors and permanent magnets to automatically return load engagement means to a predetermined lateral position, providing robust and accurate positioning through digital output signals controlling the movement of forks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If an analogous sensor is used to determine the position of the fork yoke, then the position can be determined automatically, but the signal from the sensor is influenced by external factors such as movement or play between mechanical components, causing the position indication to deviate from the true position

Engineering Contradiction:
Improveautomatic position determinationVSAvoidposition indication accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical analogous sensor system with a magnetic field-based detection system. A permanent magnet is attached to the fork yoke, and a magnetic sensor (such as a Hall sensor) is mounted on the truck frame. This substitution eliminates the direct mechanical connection between the sensor and the moving parts, thereby removing the influence of mechanical play and movement on the position measurement. The magnetic field detection provides accurate position information without being affected by mechanical component tolerances.

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

2Ease of operation

If the forks are manually positioned, then the driver can control the position, but it is difficult to determine the exact lateral position of the forks in relation to a predetermined position

Engineering Contradiction:
Improvemanual controlVSAvoidlateral position determination
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces a magnetic positioning system that provides precise lateral position determination to assist manual operation. The permanent magnet on the fork yoke interacts with the magnetic sensor on the frame to generate accurate position signals. This allows the driver to manually control the forks while having access to precise position feedback, enabling accurate centering and positioning without relying solely on visual estimation or manual judgment.

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

3Device complexity

If the forks are positioned without accurate lateral position determination, then the operation is simpler, but the forks or load may hit the support legs during vertical displacement

Engineering Contradiction:
Improvepositioning system complexityVSAvoidcollision avoidance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements a magnetic field-based position detection system that provides reliable collision avoidance information. The permanent magnet attached to the fork yoke and the magnetic sensor mounted on the frame create a contactless positioning system. This system accurately determines the lateral position of the forks, enabling the control system to prevent vertical displacement when the forks are not properly centered, thereby avoiding collisions with support legs while maintaining relatively simple device architecture.

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

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

Ensures precise and safe positioning of load engagement means, reducing the risk of collisions and enhancing operational ease by providing accurate and reliable lateral positioning of forks.

Implementation Method 1

a first digital magnetic sensor having a first side which senses a north pole of a permanent magnet and generates a first digital output signal and a second side which senses a south pole of a permanent magnet and generates a second digital output signal

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP2168904B1Industrial truck with automated lateral movement of the load engagement means
Publication Date: 2011.11.30 BT PROD
  • EP2168904B1 patent drawingFigure 1~2
  • EP2168904B1 patent drawingFigure 3a~3c
  • EP2168904B1 patent drawingFigure 4~6

AI summary

The present invention relates to an industrial truck with vertically and laterally movable load engagement means (3) comprising means for automatically returning said load engaging means (3) to a predetermined lateral position on the truck whereby said means comprises at least a first digital magnetic sensor (9) arranged on the truck, indicating a first predetermined position and at least a first magnetic means (10) arranged on the load engagement means (3), wherein the load engagement means (3) is arranged to be moved to said predetermined position according to signals generated by the digital magnetic sensor (9).