Dock Leveler Safety System with Pit Floor Sensor Surveillance
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Solution Overview
Problem
Vertically storing dock levelers pose safety risks as they descend to a lowered position, potentially colliding with personnel or objects in the pit area, as existing systems often rely on localized sensors that may not detect individuals or objects effectively until the deck is in operation, leading to accidental movements.
Innovation Solution
The implementation of a sensor system that surveys the area near the pit floor, using various sensors such as photoelectric eyes, proximity sensors, and pressure-sensitive mats to detect the presence of individuals or objects, triggering a controller to restrict the deck's movement and prevent accidental lowering, ensuring safe operation by determining the absence or presence of objects while the deck is in an upright position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If localized sensors are used to detect objects near the deck, then the device complexity is reduced, but the measurement precision and detection reliability deteriorate because sensors cannot effectively detect individuals or objects until the deck is in operation
Solution Approach 1:
The sensor system transitions from localized detection near the deck to area-wide surveillance of the pit floor, changing the detection dimension from point-based to plane-based coverage. This allows detection of individuals or objects before the deck descends, improving reliability without significantly increasing complexity through the use of distributed simple sensors like pressure-sensitive mats.
2Measurement precision
If sensors survey the area near the pit floor to detect individuals or objects early, then the detection precision improves, but the device complexity increases due to multiple sensors and control systems
Solution Approach 1:
The safety system is segmented into independent simple sensor units (photoelectric eyes, proximity sensors, pressure-sensitive mats) distributed across the pit floor area. Each sensor performs a simple detection function, and the controller integrates their signals. This segmentation achieves comprehensive area coverage and high detection precision while keeping individual component complexity low.
Solution Approach 2:
The controller acts as an intermediary that receives signals from multiple distributed sensors and processes them to determine the presence or absence of individuals or objects. This intermediary component coordinates the sensor network, enabling precise detection without requiring complex integration at the sensor level, thus managing system complexity effectively.
3Productivity
If the deck descends to a lowered position, then the productivity of loading and unloading operations improves, but the safety risk increases due to potential collisions with personnel or objects in the pit area
Solution Approach 1:
The sensor system performs preliminary detection of individuals or objects in the pit area before the deck begins its descent. The controller receives sensor signals and determines presence/absence conditions in advance, allowing the system to prevent deck movement if hazards are detected. This preliminary action eliminates collision risks while maintaining productivity by enabling safe operation when the area is clear.
Solution Approach 2:
The safety system applies preliminary anti-action by restricting deck movement when sensors detect individuals or objects in the pit area. The controller prevents the deck from descending to the lowered position when hazards are present, counteracting the potential harmful collision before it can occur. This allows uninterrupted operation when the area is safe, maintaining productivity while eliminating collision risks.
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
The safety system effectively prevents accidental collisions by determining the presence of individuals or objects before the deck descends, ensuring safe operation and preventing injuries by restricting the deck's movement when obstacles are detected, thus enhancing safety during loading and unloading operations.
Implementation Method 1
photoelectric eyes
Implementation Method 2
pressure-sensitive mats
Data Source
AI summary
Example dock leveler safety systems for vertically storing dock levelers are disclosed herein. An example dock leveler safety system disclosed herein may be used at a dock platform in a pit having a pit floor, where the pit floor is at a lower elevation than the dock platform and the dock platform and the pit floor define the pit. The dock leveler safety system comprises a deck to pivot relative to the dock platform between an upright position and a lowered position such that the deck extends farther over the pit floor when the deck is in the lowered position than when the deck is in the stored upright position. A sensor monitors a sensed region within the pit when the deck is in the upright position and the sensor provides a reaction signal in response to a body being detected within the sensed region. The deck enters a state of restricted movement in response to the reaction signal.