Industrial Truck Tiller Arm Angle Sensor Safety Control

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Solution Overview

Problem

Industrial trucks face challenges in preventing operator feet from being squeezed between the load carrier and the floor, especially at large pivot angles, and the housing movement, which existing sensor systems struggle to address effectively.

Innovation Solution

An industrial truck equipped with a horizontal pivot angle sensor that communicates with a control unit to disable the lowering of the load carrier when the pivot angle exceeds a predetermined range, and optionally disables lifting at another range, using a hydraulic system control to prevent squeezing by blocking the return flow or pump operation, with sensors like accelerometers or gyros for precise angle detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sensor is added to prevent foot squeezing, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses the existing tiller arm pivot angle sensor as an intermediary to indirectly detect foot squeezing risks. Instead of adding sensors directly to the load carrier or floor area, the system monitors the tiller arm's pivot angle as a proxy indicator. When the pivot angle exceeds a threshold, it infers that the operator's feet are in danger zone, thereby preventing foot squeezing without direct contact sensors in the hazard area.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical sensor systems with an electronic control system that utilizes existing sensor data. The control unit processes pivot angle information from the tiller arm sensor and automatically controls the hydraulic system to prevent lowering, substituting mechanical foot switches or pressure sensors with an electronic angle-based control mechanism.

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

2Reliability

If lowering is disabled at large pivot angles, then foot squeezing risk is reduced, but operational flexibility deteriorates

Engineering Contradiction:
ImprovesafetyVSAvoidoperational flexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent implements dynamic control of the lowering function based on real-time tiller arm pivot angle. The system automatically adjusts the lowering capability according to the operator's position: allowing lowering when the pivot angle is within safe ranges (operator positioned safely) and disabling it when the pivot angle exceeds thresholds (operator in danger zone). This dynamic adaptation maintains operational flexibility while ensuring safety.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system continuously monitors the tiller arm pivot angle and provides feedback to the control unit, which adjusts the lowering function accordingly. This closed-loop feedback mechanism ensures that the lowering capability is dynamically adjusted based on the operator's position, maintaining operational flexibility when safe and preventing foot squeezing when dangerous conditions are detected.

Inventive Principle:
Principle #23Feedback

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 solution significantly reduces the risk of foot squeezing by optimizing material handling operations, allowing operators to safely maneuver the truck without unnecessary restrictions, even in narrow areas or with moving truck housings, by disabling lowering and lifting at critical angles, thus enhancing safety and operational ease.

Implementation Method 1

sensors like accelerometers or gyros for precise angle detection

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

sensors like accelerometers or gyros for precise angle detection

Methodology Applied
Scientific EffectGyroscope: Gyroscope

Implementation Method 3

using a hydraulic system control to prevent squeezing by blocking the return flow or pump operation

Methodology Applied
Scientific EffectHydraulic Press: Hydraulic Press

Data Source

PatentEP3789268B1An industrial truck
Publication Date: 2022.03.23 TOYOTA MATERIAL HANDLING MFG SWEDEN
  • EP3789268B1 patent drawingFigure 1~2
  • EP3789268B1 patent drawingFigure 3~4
  • EP3789268B1 patent drawingFigure 5

AI summary

Industrial truck (1) comprising, a tiller arm (2) for maneuvering the industrial truck (1), a load carrier (3), an horizontal pivot angle sensor (4), a control unit (5), an hydraulic system (6) for operating the load carrier (3), wherein the control unit (5) operable to control functions of the industrial truck including travel and lifting function, wherein the angle sensor (4) is operable to detect the horizontal pivot angle (α) of the tiller arm (2) around a vertical axis (7), wherein the load carrier (3) is operable to be maneuvered to an elevated position, characterized in that the industrial truck (1) is arranged such that the angle sensor (4) can send detected pivot angle (α) values to the control unit (5), wherein the industrial truck (1) is arranged such that control unit (5) is operable to communicate with and control the hydraulic system (6) of the industrial truck (1), wherein the control unit (5) is arranged such that when the pivot angle (α) of the tiller arm (5) is determined by the sensor (4) to be within a first predetermined range of pivot angles (α1-α2), the control unit (5) controls the hydraulic system such that lowering of load carrier (3) is disabled.