Dual-hook Locking Device for Turbojet Nacelle Safety

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Solution Overview

Problem

The existing locking devices in turbojet engine nacelles are cumbersome and difficult to maintain due to their size, particularly at the front edge where piping is housed, and there is a need for additional locking mechanisms to ensure safety during flight, which complicates the assembly and increases stress on components.

Innovation Solution

A compact locking device with a dual-hook system where the second hook is offset from the first by 0.5 to 1.5 mm, allowing it to take over the locking function in case of failure, and actuating means to simultaneously operate both hooks, along with adjustable positioning to optimize prestress and reduce component size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional locking devices are provided at the front edge to ensure safety during flight, then reliability is improved, but device complexity and difficulty of installation increase due to piping constraints

Engineering Contradiction:
Improvesafety during flightVSAvoidlocking device assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the conventional locking function and the safety function into a single locking device by providing two hooks (first hook and second hook) that are offset from each other. The first hook performs the conventional locking function while the second hook provides the safety function. This merging eliminates the need for separate locking devices at the front edge, reducing assembly complexity while maintaining both safety and conventional locking functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking device is segmented into two distinct hooks with different functions: the first hook for conventional locking and the second hook for safety. This segmentation allows each hook to be optimized for its specific function while being part of a single integrated locking device, resolving the conflict between reliability and complexity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a complete additional locking device is provided at the front edge for safety, then reliability is improved, but ease of manufacture deteriorates due to piping constraints

Engineering Contradiction:
Improvesafety during flightVSAvoidlocking device installation ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By merging the safety function and conventional locking function into a single locking device with two offset hooks, the patent eliminates the need for separate additional locking devices. This integration significantly improves ease of manufacture and installation, as the single device can be installed in one operation without the complexity of fitting multiple separate devices around existing piping.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple separate locking devices are provided for conventional and safety functions, then reliability is improved, but compactness deteriorates

Engineering Contradiction:
Improvesafety functionVSAvoidlocking device compactness
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges two separate locking devices (one for conventional function, one for safety function) into a single compact locking device with two offset hooks. This integration maintains both functions while significantly improving compactness, as the two hooks are positioned offset from each other within the same structural component rather than requiring separate devices occupying additional space.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2178761B1Locking device
Publication Date: 2012.04.25 AIRCELLE SA
  • EP2178761B1 patent drawingFigure 1
  • EP2178761B1 patent drawingFigure 2
  • EP2178761B1 patent drawingFigure 3

AI summary

The invention relates to a locking device (13) that includes at least one locking system (16), intended to be placed on a first moving element (11), and a retaining member (17), intended to be placed on a second moving element (12), the locking system (16) having a first hook (18) designed to engage with the retaining member so as to lock the locking device (13). The locking system (16) includes at least a second hook (19) set back from the first hook (18) so as to engage with the retaining member in the event of the first hook (18) breaking.