Aircraft Attachment Return Device Reducing Operator Effort

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional return devices for aircraft attachment systems face issues with high return forces that disturb load balance, require significant operator effort, and can weaken stoppers due to violent retraction, while also risking fuel tank puncture during crashes.

Innovation Solution

A return device with an elastic return means and a gear reduction member that reduces the tensile return force, using a slender element with pulleys to divide the force and allow rapid retraction to a storage position, and locking/unlocking means to manage the attachment device's movement between storage and working positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If an elastic return means is used to retract the attachment device, then the attachment device can be automatically returned to storage position, but the return force disturbs the balance of the external load and requires significant operator effort

Engineering Contradiction:

Improveautomatic retractionVSAvoidoperator effort

Core Design Contradiction:

Extent of automationVSEase of operation

Solution Approach 1:

The return device is segmented into distinct functional components: elastic return means for generating retraction force, gear reduction member for force multiplication, and slender element for force transmission. This segmentation allows each component to be optimized independently, reducing the overall operational burden while maintaining automatic retraction capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The gear reduction member acts as an intermediary between the elastic return means and the attachment device. It transforms the high-force, short-displacement elastic return into a lower-force, longer-displacement retraction action, thereby reducing the effort required by operators while preserving automatic retraction

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a high return force is used to maintain the attachment device in storage position during accelerations, then the device remains secure, but the violent retraction weakens stoppers and increases wear

Engineering Contradiction:

Improvesecurity during accelerationsVSAvoidstopper durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The system incorporates cushioning elements and controlled retraction mechanisms that absorb and dissipate the energy of violent returns before they reach the stoppers. This beforehand cushioning protects the stoppers from excessive wear while maintaining the high return force needed for security during aircraft accelerations

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The violent retraction force, which initially appears harmful to the stoppers, is converted into a beneficial controlled action through the gear reduction member and damping elements. The energy that would otherwise damage the stoppers is transformed into a controlled retraction process that secures the attachment device while minimizing wear on mechanical components

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If the attachment device is positioned close to the rotor axis to limit disturbances, then flight behavior is improved, but the risk of fuel tank puncture during crash increases

Engineering Contradiction:

Improveflight behaviorVSAvoidcrash damage risk

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The attachment device transitions from a static fixed position to a dynamic reconfigurable position. During normal flight, it operates close to the rotor axis for optimal flight behavior. During crash or emergency conditions, the elastic return means automatically retracts it to a safe position away from fuel tanks, adapting to different operational states to eliminate the harmful crash risk while preserving flight performance

Inventive Principle:

Principle #15Dynamics

4Force

If the elastic return means is stretched to provide sufficient return force, then the attachment device can be held in storage position, but the return force increases and disturbs load balance when load is present

Engineering Contradiction:

Improvereturn forceVSAvoidload balance

Core Design Contradiction:

ForceVSStability of the object's composition

Solution Approach 1:

The system changes the operational parameters of the elastic return means through the gear reduction member. By transforming the force-displacement characteristics, the system maintains high return force when needed (empty attachment device) while reducing the disturbing effect on load balance when external loads are present, as the gear reduction allows the same elastic element to operate in different force ranges

Inventive Principle:

Principle #35Parameter changes

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 solution effectively retracts the attachment device away from sensitive areas without disturbing load balance, reduces operator effort, and maintains the device in the storage position during aircraft accelerations, while allowing smooth deployment under load, thus enhancing safety and reducing wear on stoppers.

Implementation Method 1

a return device comprising an elastic return means (11) exerting a tensile return force on the attachment device (15)

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a gear reduction member (12) making it possible to reduce the tensile return force exerted by the elastic return means (11) on the attachment device (15), an elongated element (20), a first free end (21) of which is secured to the attachment device (15) and a second free end (22) of which is secured to the gear reduction member (12)

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP3225547B1A return device for retracting a movable attachment device, and an aircraft fitted with such a return device

Publication Date: 2018.08.22 EUROCOPTER FRANCE SA

Figure 1~2
Figure 3
Figure 4~5

AI summary

The present invention relates to a return device (10) for retracting an attachment device (15) of an aircraft (6), said attachment device (15) being movable between a retracted storage position and a deployed working position (POS2), said return device (10) tending to place said attachment device (15) in said retracted storage position in the absence of an external load (5) while allowing the movement of the attachment device (15) towards said deployed working position (POS2) in the presence of an external load (5), characterized in that said return device (10) comprises: • an elastic return means (11) for exerting a tensile return force on said attachment device (15) and automatically returning said attachment device (15) to said retracted storage position,• a multiplication element (12) for said tensile restoring force exerted by said elastic restoring means (11) on said attachment device (15), • a longitudinal element (20) comprising a first free end (21) fixed to said attachment device (15) and a second free end (22) fixed to said multiplication element (12).