Flip Door Interlock for Fall Protection

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Solution Overview

Problem

Workers on raised platforms in manufacturing environments, particularly during aircraft fuselage assembly, face fall risks due to flip doors that are not adequately secured, posing a safety hazard when opened.

Innovation Solution

A flip door assembly with an interlock mechanism that requires a safety barrier to be engaged before the door can be opened, preventing inadvertent opening and ensuring the barrier remains in place while the door is open to prevent falls, and allowing removal only when the door is closed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If flip doors are opened to allow workers to access the fuselage or equipment to pass through, then accessibility is improved, but fall risk increases

Engineering Contradiction:
ImproveaccessibilityVSAvoidfall risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

An interlock mechanism acts as an intermediary between the safety barrier and the flip door. The interlock includes a receptacle that receives a keyed portion of the barrier, and a locking member that prevents door opening when the barrier is disengaged. This intermediary mechanism ensures that the door can only be opened when the safety barrier is properly in place, thus maintaining accessibility while preventing falls.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a safety barrier is added to prevent falls, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The safety barrier system is merged with the existing flip door assembly. The interlock mechanism is integrated into the door structure, with the receptacle and locking member becoming part of the door assembly rather than separate components. This merging approach enhances safety while minimizing the increase in overall system complexity by utilizing the existing door structure.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If the interlock mechanism prevents door opening when barrier is disengaged, then fall prevention is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvefall preventionVSAvoiddoor operation
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The system requires preliminary engagement of the safety barrier before the flip door can be opened. The interlock mechanism is designed so that the keyed portion of the barrier must first be inserted into the receptacle, which then releases the locking member to allow door opening. This preliminary action ensures safety is established before access is granted, preventing falls while maintaining operational clarity.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3878757B1Locking mechanism for fall protection
Publication Date: 2023.05.17 THE BOEING CO
  • EP3878757B1 patent drawingFigure 1
  • EP3878757B1 patent drawingFigure 2
  • EP3878757B1 patent drawingFigure 3

AI summary

A flip door assembly includes a flip door and an interlock that controls whether the flip door may be opened. A worker safety system in one embodiment includes a work stand, a safety barrier, and a flip door assembly. The flip door assembly selectively engages with a keyed portion of the safety barrier to prevent access to a defined area by a worker. The flip door assembly includes a flip door having a top surface that is substantially planar to a top surface of the work stand when closed, and substantially non-planar to the top surface of the work stand when open. The flip door assembly further includes an interlock that prevents the flip door from opening when the keyed portion of the safety barrier is disengaged from the interlock, and allows the flip door to open when the keyed portion of the safety barrier is engaged with the interlock.