Underwing Flap Support Clevis With Fuse-Pin Ground-Strike Release
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Solution Overview
Problem
Commercial aircraft wing flaps often contact the ground during landing, causing potential damage to the wing structure, and existing structural joints are heavy, costly, and inefficient in managing this contact.
Innovation Solution
An underwing flap support structure featuring a one-piece underwing beam with an integral clevis and a spherical bearing support assembly, allowing the beam to pivot and detach from the wing upon ground contact, minimizing damage through a shear force mechanism and failsafe catcher system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the underwing beam is directly connected to the wing structure, then structural strength is improved, but weight and complexity increase
Solution Approach 1:
The connection system is segmented into modular components: the underwing beam, spherical bearing support assembly, clevis, and fuse pin. This segmentation allows each component to be optimized independently, reducing overall weight while maintaining structural integrity through the bearing-supported connection.
Solution Approach 2:
The spherical bearing support assembly acts as an intermediary between the underwing beam and the wing structure. It provides a controlled connection mechanism that reduces stress concentrations and distributes loads more efficiently, allowing for weight reduction in the overall structure.
2Stability of the object's composition
If the underwing beam is rigidly attached to the wing, then structural stability is improved, but damage from ground contact increases
Solution Approach 1:
The connection system transitions from a static rigid attachment to a dynamic controlled-separation system. The spherical bearing allows rotational movement, and the fuse pin provides a controlled failure mode that enables the underwing beam to detach during ground contact while maintaining stability during normal operation.
Solution Approach 2:
The potential harmful effect of ground contact is converted into a beneficial controlled separation mechanism. The fuse pin is designed to shear under excessive load, transforming the harmful impact force into a controlled detachment that protects the main wing structure from damage.
3Strength
If complex joint structures are used to prevent detachment, then structural integrity is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The fuse pin is designed as a sacrificial, disposable component that is replaced after shear failure. This allows the use of a simple, inexpensive pin rather than a complex, expensive reusable locking mechanism, significantly reducing manufacturing costs while maintaining structural integrity during normal operation.
Solution Approach 2:
The complex prevention-of-detachment function is extracted from the main structure and embodied in the separate, replaceable fuse pin component. This extraction simplifies the main structural components and reduces overall manufacturing complexity while maintaining the required structural integrity.
4Reliability
If multiple attachment points are used, then structural reliability is improved, but device complexity increases
Solution Approach 1:
The spherical bearing support assembly serves multiple functions simultaneously: it provides structural support, allows controlled rotation, enables detachment through fuse pin shear, and acts as a mounting point for the underwing beam. This multi-functionality reduces the need for separate components at multiple attachment points, simplifying the overall device while maintaining reliability.
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 reduces weight, cost, and damage to the wing structure by enabling controlled separation of the underwing beam from the wing, maintaining structural integrity and reducing installation complexities.
Implementation Method 1
a spherical bearing support assembly carrying a race and a spherical bearing
Implementation Method 2
a force applied to an aft portion of the underwing beam that is sufficient to urge separation from the wingbox creates a moment inducing the one-piece underwing beam to apply a shear force to enable the one-piece underwing beam and the integral clevis to pivot, shear the forward-aft oriented fuse pin
Data Source
AI summary
An underwing flap support mounting structure is disclosed that includes an underwing beam comprising an integral clevis at a forward end of the underwing beam and mounted to a lower skin of a wingbox, wherein the integral clevis comprises a first clevis bore and second clevis bore; and a wingbox lug fitting comprising a wingbox lug and a spherical bearing support assembly carrying a race and a spherical bearing, the wingbox lug having a wingbox lug bore and the spherical bearing having a spherical bearing bore, wherein a forward-aft oriented fuse pin is slidably received in the spherical bearing bore, the first clevis bore, and the second clevis bore to inhibit relative linear-vertical motion of the underwing beam and the integral clevis relative to a wingbox lug fitting that is mounted to the lower skin of the wingbox.