Flexible Coupling with Bayonet Backup for Torque Continuity

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Solution Overview

Problem

Existing flexible coupling means for rotating mechanical components face challenges in minimizing the risk of torque transmission rupture due to diaphragm failure while maintaining a simple structure, especially under conditions of axial and angular misalignment.

Innovation Solution

A flexible coupling mechanism featuring a first and second member with diaphragms connected via a fastening system, incorporating a bayonet system as an emergency torque transmission device that allows rotational drive through circumferential play and axial clearances, ensuring continuity of torque transmission in case of diaphragm rupture, and featuring a simple structure with minimal mechanical parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single diaphragm coupling means is used to connect rotating members, then the structure remains simple, but the risk of torque transmission rupture increases when diaphragm rupture occurs

Engineering Contradiction:
Improvestructure simplicityVSAvoidtorque transmission continuity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by providing a backup torque transmission path through longitudinal splines that are prepared in advance. When the diaphragm ruptures, the splines immediately engage to prevent torque transmission interruption, thus cushioning against the harmful effect of diaphragm failure while maintaining structural simplicity.

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

Solution Approach 2:

The patent implements discarding and recovering by allowing the diaphragm to be discarded (ruptured) as a sacrificial element that protects the main rotating members. The backup spline mechanism recovers the torque transmission function after diaphragm failure, ensuring continuous operation while maintaining the simple single-coupling structure.

Inventive Principle:
Principle #34Discarding and recovering

2Reliability

If backup torque transmission devices are added to protect against diaphragm rupture, then torque transmission continuity is improved, but the number of mechanical parts increases and manufacture becomes complicated

Engineering Contradiction:
Improvetorque transmission continuityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the backup torque transmission function directly into the coupling means structure by integrating longitudinal splines into the member bodies. This combination eliminates the need for separate backup devices, reducing the number of mechanical parts while ensuring torque transmission continuity after diaphragm rupture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies universality by designing the member bodies to serve multiple functions: they provide structural support, accommodate diaphragm attachment, and contain integrated spline mechanisms for backup torque transmission. This multi-functionality reduces the overall number of parts and simplifies manufacturing while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If diaphragms are made thin to maintain simple structure, then device complexity is reduced, but fragility increases beyond nominal misalignment conditions

Engineering Contradiction:
Improvestructure simplicityVSAvoiddiaphragm durability
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent applies beforehand cushioning by preparing backup spline mechanisms that engage when diaphragms fail under excessive stress. The thin diaphragms can be made simpler while the pre-positioned splines cushion against the harmful effects of diaphragm rupture, protecting the rotating members from damage.

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

Solution Approach 2:

The patent implements this principle by using thin, simpler diaphragms as disposable sacrificial elements that protect the more critical rotating members. When diaphragms rupture under excessive stress, the backup splines take over, allowing the diaphragms to be replaced without damaging the main system, thus maintaining structural simplicity while improving durability.

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

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 coupling mechanism effectively maintains torque transmission between rotating members even after diaphragm rupture, protecting the diaphragms from excessive stress and allowing axial and angular misalignment, while maintaining a simplified structure and operation under normal conditions.

Implementation Method 1

In addition, the coupling means comprises, in the absence of said rupture of a diaphragm or of a connection between two diaphragms, an axial play in compression, an axial play in tension and a circumferential play between each protuberance and walls delimiting the corresponding bent groove.

Methodology Applied
Scientific EffectCircumferential play and axial clearances:

Implementation Method 2

Each annular disc is sometimes referred to as a 'diaphragm'. The term diaphragm is therefore used hereafter for convenience. Therefore, the two ring members are connected to each other only via the outer periphery of their diaphragm.

Methodology Applied
Scientific EffectFlexible deformation: Elasticity

Data Source

PatentEP2657558B1Flexible coupling means, and mechanical transmission
Publication Date: 2015.03.04 EUROCOPTER FRANCE SA
  • EP2657558B1 patent drawingFigure 1~2
  • EP2657558B1 patent drawingFigure 3~4

AI summary

The present invention relates to a coupling means (10) having a first member (20) suitable for being fixed to a first rotating member (2) and a second member (30) suitable for being fixed to a second rotating member (3), the first member (20) being provided with a first diaphragm (22) and the second member (30) being provided with a second diaphragm (32) secured to the first diaphragm (22). A backup torque transmission device includes at least one bayonet system including a protrusion (50) integral with a member (30) cooperating with a bent groove (60) integral with the other member (20) by being inserted into the bent groove (60) by a push-rotation movement, said coupling means (10) comprising in the absence of said break axial clearances in compression (70') and in tension (70") and a circumferential clearance between each protrusion (50) and walls delimiting the corresponding bent groove (60).