Dock Leveller Safety Device Using Electronic Sensor Detection
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Solution Overview
Problem
Existing dock leveller safety devices are not reliable in preventing free-falls due to variations in vehicle dimensions and parking distances, and regular testing is often impractical due to high test weights, which can reduce the dock leveller's lifetime and lead to undetected malfunctions.
Innovation Solution
A dock leveller with an electronically controlled valve and sensor system that detects deck movement velocity and acceleration, automatically stopping the deck when a preset threshold is exceeded, and a method for testing the safety device to ensure compliance with EN1398 standards, allowing for reliable fall prevention and reduced wear on the dock leveller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hose break valve is used for fall prevention, then the deck is protected from free-fall, but different valve types are needed for different dock leveller designs
Solution Approach 1:
The patent replaces the mechanical hose break valve system with an electronic control system comprising position sensors, control units, and electronically controlled valves. This substitution allows the fall prevention function to be implemented through software control rather than mechanical pressure-actuated valves, enabling universal application across different dock leveller designs while maintaining reliable fall protection.
2Reliability
If an electronic sensor detects vehicle position for fall prevention, then the deck is protected from free-fall, but the protection reliability decreases due to vehicle dimension variations
Solution Approach 1:
The patent introduces an intermediary mechanical linkages system that physically connects the sensor to the deck position measurement. Instead of directly measuring vehicle position, the system uses linkages to translate deck position into sensor-readable signals, providing indirect but more reliable measurement of the actual safety-critical parameter (deck position) rather than the variable parameter (vehicle position).
3Reliability
If regular testing with test load is performed, then the safety device functionality is verified, but the dock leveller lifetime is reduced due to high test weights
Solution Approach 1:
The patent creates a simplified test configuration that copies the essential safety test requirements without requiring full test loads. By using the electronic control system and position sensors, the system can verify safety functionality through controlled deck position measurements and electronic valve operation testing, eliminating the need for heavy physical test loads while still confirming safety device effectiveness.
4Adaptability or versatility
If the deck is free-floating during normal operation, then the deck adapts to vehicle bed movement, but the deck becomes vulnerable to free-fall when vehicle support is removed
Solution Approach 1:
The patent implements a feedback control system where position sensors continuously monitor deck position and vehicle presence, and the control unit adjusts the electronically controlled valves to maintain safety. During normal operation, the system allows free-floating behavior while continuously monitoring conditions. When a free-fall risk is detected (vehicle moves away or deck position becomes unsafe), the system automatically actuates the valves to stop deck movement, providing adaptive protection that maintains both operational flexibility and safety.
Data Source
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AI summary
The invention relates to safety device (11) for use in a dock leveller (10) having a deck (15) pivotally connected to a ramp (12), at least one electronically controlled valve (23) for stopping a movement of the deck (15) in response to a control signal, and at least one electronic sensor (25). For enhancing the safety device (11) such that the functionality is enhanced and/or that a testing can be performed in an effective and reliable way the electronic sensor (25) is constructed and/or arranged to detect a fall-movement of the deck (15).