Passive Mechanical Locking for Lift Gate Fall Protection

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Solution Overview

Problem

Conventional fall protection systems for lifting gates, especially those used in industrial settings to prevent collisions with robot arms, are complex, maintenance-intensive, and require active control, making them costly and unreliable.

Innovation Solution

A passive mechanical locking device with a stop element and articulated jack mechanism that locks the gate carrier in place, using a spring force to secure the gate against unwanted vertical movements, allowing it to be easily unlocked by the drive device for operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fall protection systems with active control are used, then the lifting gate can be securely held in position, but the system becomes complex and maintenance-intensive

Engineering Contradiction:
Improvesecurity of lifting gateVSAvoidcomplexity of fall protection system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fall protection device operates autonomously without requiring external control signals. The articulated jack automatically engages the locking position when the lifting gate reaches its upper position and disengages when the gate moves downward, making the system self-regulating and eliminating the need for complex control systems while maintaining reliability

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention replaces complex electronically-controlled mechanical systems with a purely mechanical solution. The articulated jack uses mechanical linkages and spring forces to achieve automatic locking and unlocking, substituting electronic controls with mechanical self-regulation based on the gate's position and movement

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

2Reliability

If active control systems are implemented for fall protection, then the lifting gate can be reliably locked, but the system requires more maintenance

Engineering Contradiction:
Improvelocking reliabilityVSAvoidmaintenance intensity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The device automatically responds to the lifting gate's position and movement without requiring external control systems. The articulated jack self-activates through mechanical linkages when the gate reaches the upper position and self-deactivates when the gate moves down, eliminating maintenance-intensive electronic controls and sensors

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention uses simple, robust mechanical components that are inexpensive and durable. The articulated jack consists of basic mechanical elements like linkages, springs, and locking surfaces that can be easily replaced if needed, rather than complex electronic assemblies that require specialized maintenance

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If a passive mechanical locking device is used, then the system is simpler and requires less maintenance, but it must still reliably prevent downward movement

Engineering Contradiction:
Improvesimplicity of fall protectionVSAvoidprevention of downward movement
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The articulated jack employs spring forces that act as a counteracting force to prevent downward movement of the lifting gate. The springs are pre-loaded to generate sufficient locking force to counteract the weight of the gate and any external downward forces, ensuring reliable prevention of unintended movement

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The articulated jack uses curved guiding surfaces and rotational joints that allow smooth engagement and disengagement while maintaining reliable locking. The curved geometry of the locking surfaces ensures positive mechanical engagement that reliably prevents downward movement while allowing controlled movement in the intended direction

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Reliability

If the stop element strikes the gate carrier hard to prevent upward movement, then the gate is securely positioned, but the impact force may cause damage

Engineering Contradiction:
Improvepositioning accuracyVSAvoidimpact damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The stop element is designed to gradually decelerate the gate carrier as it approaches the upper position rather than causing a sudden hard impact. The articulated jack's mechanical linkages and spring elements act as cushioning elements that absorb the impact energy, preventing damage while ensuring the gate reaches its correct positioned

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 solution provides a reliable, low-maintenance, and cost-effective fall protection that securely holds the lifting gate in place without active control, preventing accidents from robot arm collisions while allowing for easy operation of the gate.

Implementation Method 1

using a spring force to secure the gate against unwanted vertical movements

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3748112B1Anti-fall device for a lift gate, in particular for protecting machinery
Publication Date: 2022.10.19 BRUHL SAFETY GMBH
  • EP3748112B1 patent drawingFigure 1
  • EP3748112B1 patent drawingFigure 2~3
  • EP3748112B1 patent drawingFigure 4

AI summary

The invention relates to a fall protection device for a lifting gate, in particular a machine guard lifting gate, with a mechanical locking device comprising a gate carrier movable in a vertical direction for common movement with the lifting gate and a support element fixed in the vertical direction, which can be brought into a mechanically locked engagement that blocks a vertical movement of the gate carrier.The invention is characterized in that the locking device further comprises at least one latch pivotably connected, at least indirectly, to the gate carrier, which can be pivoted into the mechanically locking engagement with the support element, and that a stop element is spring-loaded on the gate carrier, which has a guide in which the latch is guided in such a way that it is pivoted in the direction of the support element when the stop element is spring-loaded, wherein the stop element is assigned a stop in a predetermined vertical end position, against which the stop element abuts during a vertical movement of the gate carrier.