Fail-Safe Rotational Guide Structure for Flight Control Bearings

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Solution Overview

Problem

Rotational connection devices in flight control systems are prone to failure due to breakage of male and female elements, leading to loss of haptic feedback and movement measurement functions, which can result in catastrophic situations.

Innovation Solution

The rotational connection device is designed with a female element comprising two parts and a bearing that is fixed by multiple means, including ears with drilling, to maintain the bearing's position independently of breakage, ensuring continuous rotation guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single male element and female element are used for rotational connection, then the device complexity is reduced, but the reliability is compromised due to potential breakage causing loss of control function

Engineering Contradiction:
Improvecontrol function reliabilityVSAvoidrotational connection structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The male element is divided into a first male element part and a second male element part, while the female element is divided into a first female element part and a second female element part. Each part independently carries the bearing, so that breakage of one part does not cause loss of rotational guidance function. This segmentation resolves the contradiction by distributing the load and function across multiple parts, maintaining reliability without requiring a completely complex redundant system.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the bearing is fixed to only one element, then the ease of manufacture is improved, but the reliability deteriorates as breakage of that element causes bearing displacement and loss of function

Engineering Contradiction:
Improvebearing position stabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bearing fixation is segmented across two independent elements (first male element part with first fixing means and first female element part with second fixing means). This allows the bearing to be securely held by multiple independent attachment points, maintaining reliability while keeping each individual fixation method simple and manufacturable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bearing is pre-fixed to both the male and female element parts before final assembly. This preliminary action ensures that the bearing is already secured to multiple elements, so that even if one element breaks, the bearing remains in position. This approach maintains reliability without requiring complex post-assembly adjustments.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If redundant bearing fixation is implemented, then the reliability is improved, but the device complexity increases due to additional fixing means

Engineering Contradiction:
Improverotational guidance reliabilityVSAvoidfixing mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The redundancy is achieved through segmentation of the elements themselves (first and second parts of male and female elements), each with simple fixing means. Rather than adding complex redundant fixation mechanisms, the invention segments the elements so that each segment independently carries the bearing, providing reliability through distribution rather than through complex redundancy.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4251893B1Fail-safe guide device
Publication Date: 2024.09.18 SAFRAN SA
  • EP4251893B1 patent drawingFigure 1
  • EP4251893B1 patent drawingFigure 2
  • EP4251893B1 patent drawingFigure 3

AI summary

The invention relates to a device comprising: - a mount (10), - a frame (20) mounted so as to rotate relative to the mount; - a control arm (40) mounted so as to rotate on the frame (20); a roll spider (80) mounted so as to rotate on the frame (20); - a pitch spider (100) mounted so as to rotate on the control arm (40); - a roll motor (120) which is fixed relative to the frame (20) and which comprises a roll shaft (121) mounted so as to rotate on the roll spider (80); - a pitch motor (140) which is fixed relative to the frame (20) and which comprises a pitch shaft (141) mounted so as to rotate on the pitch spider (100). Drawing_references_to_be_translated