Helicopter Tail Folding Mechanism Spline Coupling

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Solution Overview

Problem

Existing helicopter tail folding mechanisms face issues with alignment, reliability, load-bearing capacity, and maintenance due to the use of face gear couplings, which are inflexible and require frequent maintenance.

Innovation Solution

A tail folding mechanism utilizing a threaded first and second shaft with form-fitting hubs, a dampener, and a wave spring for efficient power transmission and decoupling, allowing for lighter and more economical folding with improved reliability and reduced maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If face gear coupling is used for tail folding mechanism, then power transmission is achieved, but alignment precision and reliability deteriorate

Engineering Contradiction:

Improvecoupling reliabilityVSAvoidalignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces the traditional face gear coupling mechanism with a spline-based coupling system. This substitution eliminates the alignment and reliability issues inherent in face gear couplings by using a more robust spline engagement mechanism that provides inherent alignment tolerance and more reliable power transmission during tail folding operations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary coupling mechanism that acts as a mediator between the driving and driven shafts during tail folding. This intermediate coupling system allows for smooth engagement and disengagement while maintaining power transmission, resolving the alignment and reliability problems of direct face gear coupling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If face gear coupling is used for tail folding mechanism, then power transmission is achieved, but load bearing capacity deteriorates

Engineering Contradiction:

Improveload bearing capacityVSAvoidpower transmission capacity

Core Design Contradiction:

StrengthVSPower

Solution Approach 1:

The patent substitutes the face gear coupling with a spline-based power transmission system that provides superior load bearing capacity. The spline mechanism distributes loads more effectively across multiple contact points, thereby increasing the overall strength and load bearing capacity while maintaining full power transmission capability during tail folding operations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of repair

If face gear coupling is used for tail folding mechanism, then coupling function is achieved, but maintenance interval shortens

Engineering Contradiction:

Improvemaintenance intervalVSAvoidcoupling reliability

Core Design Contradiction:

Ease of repairVSReliability

Solution Approach 1:

The patent replaces the maintenance-intensive face gear coupling with a spline-based coupling system that requires less frequent maintenance. The spline mechanism's simpler structure and more robust engagement characteristics reduce wear and the need for frequent maintenance interventions, thereby extending maintenance intervals while improving coupling reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Weight of moving object

If traditional tail folding mechanism is used, then folding function is achieved, but mechanism weight increases

Engineering Contradiction:

Improvemechanism weightVSAvoidfolding operation efficiency

Core Design Contradiction:

Weight of moving objectVSEase of operation

Solution Approach 1:

The patent substitutes traditional heavy-duty coupling mechanisms with a lighter spline-based coupling system that maintains full folding functionality. This substitution reduces the overall weight of the tail folding mechanism while preserving the ability to perform folding operations effectively, thereby improving the weight-to-functionality ratio.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 mechanism enables efficient and reliable tail folding without damaging helicopter parts, providing a lighter, more practical, and economical solution with enhanced load management and reduced maintenance intervals.

Implementation Method 1

Dampener is located in the front region and has a damping function

Methodology Applied

Scientific EffectDamping: Damping

Implementation Method 2

a wave spring for efficient power transmission and decoupling

Methodology Applied

Scientific EffectWave spring: Spring

Data Source

PatentUS12179901B2Tail folding mechanism

Publication Date: 2024.12.31 TUSAS TURK HAVACILIK VE UZAY SANAYII ANONIM SIRKETI

AI summary

A folding mechanism for a tail located on a helicopter has a front region on the tail, a rear region connected to the front region can be folded around the axis on which it is supported, a first shaft located on the front region and a second shaft located on the rear region enables power to be transmitted to the tail rotor during the flight movement of the helicopter, a first coupling and a second coupling located on the first shaft with a threaded form, a first hub located on the first shaft surrounding the first coupling all around and is form-fitting to the first coupling to enable the first coupling to make at least a partial spherical rotational movement, and a second hub located on the second shaft is arranged opposite the second coupling and being form-fitting to the second coupling with a dampener located on the front region.