Reactor Wall Repair Socket With Floating Nut for Vibration Loosening

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Solution Overview

Problem

The existing fastening systems for panels in turbofan engines are prone to loosening due to vibratory stresses, leading to ovalization of holes and potential destruction of the cage nut and deterioration of the contact surface, necessitating a simple and effective replacement method for both new and existing engines.

Innovation Solution

A fastening system involving a sleeve with a floating nut that is locked in rotation within a socket body, allowing for easy installation and replacement by drilling a larger hole to accommodate the sleeve, which includes a self-tapping socket body and a caged nut for secure panel fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional fastener with a hole and cage nut is used to fix panels to the engine shell, then the panel can be secured at a distance from the shell face, but the fastener loosens under vibratory stresses causing hole ovalization and cage destruction

Engineering Contradiction:
Improvefastener reliabilityVSAvoidhole shape stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The fastening system is divided into separate functional components: a socket body that remains fixed in the shell, a floating nut that absorbs vibrations, and a panel that is secured. This segmentation allows each component to perform its specific function optimally, with the floating nut isolating vibratory stresses from the fixed socket body and hole structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The floating nut acts as an intermediary element between the fixed socket body and the panel. It absorbs and isolates the vibratory stresses that would otherwise be transmitted to the hole and cause ovalization, while still maintaining the secure connection to the panel through thread engagement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the existing fastener is replaced, then the reliability can be improved, but the replacement process is complex and time-consuming

Engineering Contradiction:
Improvefastener reliabilityVSAvoidfastener replacement ease
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The socket body is pre-installed and fixed to the engine shell before the panel is attached. This preliminary action creates a stable, vibration-resistant foundation that eliminates the need for complex removal and reinstallation procedures, as only the panel and floating nut need to be removed for replacement, not the entire fastening system.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By separating the fixed socket body from the removable floating nut and panel assembly, the system enables simple replacement of only the worn floating nut without disturbing the securely anchored socket body, significantly reducing repair complexity and time.

Inventive Principle:
Principle #1Segmentation

3Reliability

If a secure fastening system is designed to resist vibrations, then the panel attachment reliability improves, but the installation complexity increases

Engineering Contradiction:
Improvepanel attachment reliabilityVSAvoidfastening system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fastening system segments vibration resistance functionality into the floating nut component, which is specifically designed to absorb vibratory stresses through its ability to move independently within the socket body. This isolates the complexity of vibration resistance to a single component rather than requiring a complex integrated system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The floating nut is designed to be dynamically movable within the socket body, allowing it to adapt to and absorb vibratory movements. This dynamic capability provides vibration resistance without requiring complex mechanical structures, as the simple floating design naturally accommodates vibrational forces.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3234311B1System for repairing a fastener equipping a reactor wall
Publication Date: 2021.01.27 SAFRAN AIRCRAFT ENGINES SAS
  • EP3234311B1 patent drawingFigure 1~2
  • EP3234311B1 patent drawingFigure 3~5
  • EP3234311B1 patent drawingFigure 6~10

AI summary

An attachment system intended to equip a wall (17), said system including a nut intended to receive a screw (31) of which the orientation is normal to the wall (17), said screw (31) passing through an element such as an outer panel (32) in order to attach said element to the wall (17). The attachment system comprises a socket (26) having a threaded cylindrical outer face (34) intended to be screwed into a hole (29) passing through the wall (17) and having dimensions greater than the dimensions of the fastener that said repair socket (26) replaces, said socket (26) carrying, in the central region of same, a nut (28) receiving the attachment screw (32).