Aircraft Window Sealed Frame Segmentation

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Solution Overview

Problem

Large aircraft windows require a seal that can withstand significant thermal expansions, aerodynamic forces, and differential pressures while being releasable for emergency evacuation, but existing solutions are either incompatible with aircraft conditions or excessively costly and cumbersome.

Innovation Solution

A sealed frame with separate sealing joints for the window and supporting structure, using removable and rigid retaining means to clamp the seals in place, allowing for thermal expansion and easy release, and utilizing elastomer seals with U-shaped sections to optimize sealing and load transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single seal is used to secure the window to the supporting structure, then the sealing function is provided, but the seal must be excessively enlarged to accommodate thermal expansion and differential pressure, increasing its mass and deteriorating its visual appearance

Engineering Contradiction:
Improvesealing functionVSAvoidseal mass
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The single seal is divided into two separate seals: a first seal arranged on the window periphery and a second seal arranged on the supporting structure periphery. This segmentation allows each seal to be optimized for its specific function and size, eliminating the need for an excessively enlarged single seal to accommodate both sealing and thermal expansion requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A retaining means is introduced as an intermediary element between the two seals. This retaining means maintains the window and supporting structure in abutment against the respective seals, enabling the seals to function effectively at smaller sizes while still providing reliable sealing under thermal expansion and pressure differential conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the seal core is cut to separate the window from the supporting structure for evacuation, then emergency release is enabled, but the frame becomes non-reusable and manufacturing costs increase for each window type

Engineering Contradiction:
Improveemergency releaseVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The sealing system is segmented into separate reusable components (first seal, second seal, and retaining means). The retaining means can be released and reused, while only the seals are replaced. This segmentation eliminates the need to manufacture entirely new frames for each window type and allows the retaining means to be reused across multiple windows.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of discarding the entire frame structure after cutting the seal core, the invention allows recovery and reuse of the retaining means. Only the seals are discarded and replaced, significantly reducing manufacturing costs and enabling the system to be adapted to different window types without creating waste.

Inventive Principle:
Principle #34Discarding and recovering

3Adaptability or versatility

If a removable retaining means is used to clamp the seals, then the window can be easily released for evacuation and the system becomes reusable, but the device complexity increases with multiple separate components

Engineering Contradiction:
ImprovereusabilityVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system is segmented into three distinct functional components: first seal, second seal, and retaining means. This segmentation provides adaptability and reusability while keeping each component relatively simple in design. The modular nature allows easy replacement of seals while retaining the complex retaining mechanism for reuse.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If separate sealing joints are used for the window and supporting structure, then thermal expansion play is accommodated and manufacturing costs are reduced, but the device complexity increases with multiple sealing components

Engineering Contradiction:
Improvemanufacturing costVSAvoidsealing system structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The sealing system is divided into separate first and second seals arranged on different peripheries, allowing each seal to be manufactured independently at lower cost while accommodating thermal expansion. The segmentation enables standardization of seal components that can be used across different window types.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separate seal design creates a universal system where the same seal components and retaining means can be used with different window types and sizes. This multi-functionality reduces manufacturing costs through economies of scale while the modular structure manages the complexity of accommodating various thermal expansion requirements.

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

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 provides a cost-effective, adaptable, and reusable sealing system that maintains the window in place under various conditions while allowing for easy release during emergencies, optimizing manufacturing costs and mechanical performance.

Implementation Method 1

the seal must be able to allow significant play between the window and the supporting structure to take into account the differential expansions of the supporting structure and the window

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the frame is provided with a removable and rigid retaining means for clamping the first and second seals as well as the window and the supporting structure

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2159154B1Sealed window frame
Publication Date: 2011.07.06 EUROCOPTER FRANCE SA
  • EP2159154B1 patent drawingFigure 1~3
  • EP2159154B1 patent drawingFigure 4~6

AI summary

The frame has two sealing joints (11, 12) respectively positioned on a peripheral edge (3') of a window (3) and a peripheral edge (2') of a carrier structure (2). A detachable maintenance unit (20) maintains the edge of the window in one of the joints and the edge of the carrier structure in the other joint. The maintenance unit includes locking units (21, 22) cooperating with each other in a reversible manner for tightly fitting the former joint and the window and for tightly fitting the latter joint and the carrier structure.