Rotational Joint for Aircraft Folding Wing Oblique Cut
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Solution Overview
Problem
Existing aircraft with foldable wings face challenges in reducing span for ground operations due to clashing inner and outer wing parts, requiring secondary structures and limited internal volume at junctions, making it difficult to integrate actuation mechanisms, especially with oblique cut planes.
Innovation Solution
Aircraft design featuring a rotational joint with a follower and guide, where the wing tip device is rotatable about an Euler axis, separated by an oblique cut plane, allowing for load transfer across the joint through an arcuate path, enabling effective load distribution and movement between flight and ground configurations without clashing, using interlocking rings for continuous interface and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the wing tip device is separated by an oblique cut plane to avoid clashing during rotation, then the span reduction for ground operations is achieved, but the integration of actuation mechanisms becomes difficult
Solution Approach 1:
A rotational joint acts as an intermediary mechanism between the fixed wing and the wing tip device. This joint includes a follower and guide that interlock to transfer loads while allowing relative rotation. The rotational joint mediates the connection across the oblique cut plane, enabling the wing tip device to rotate between flight and ground configurations while maintaining structural integrity and load transfer capability.
2Adaptability or versatility
If a rotational joint with follower and guide is used to enable rotation about Euler axis, then movement between configurations is achieved, but load transfer across the joint becomes challenging
Solution Approach 1:
The guide defines an arcuate path that curves about the Euler axis at a radial distance from it. This curved geometry allows the follower to move along the arcuate path during rotation, enabling the joint to accommodate the rotational movement while maintaining load transfer capability across the joint.
3Ease of operation
If the follower moves along the arcuate path defined by the guide, then rotation is enabled, but rubbing and wear increase
Solution Approach 1:
The patent replaces direct mechanical contact and sliding with a rotational joint system that uses a follower moving along a guided arcuate path. This substitution reduces rubbing and wear by ensuring controlled, constrained movement rather than direct friction-based contact, thereby improving reliability while maintaining rotation capability.
4Length of moving object
If the fixed wing and wing tip device are separated by an oblique cut plane, then clashing is avoided, but sealing of actuation mechanism becomes difficult
Solution Approach 1:
The rotational joint serves as an intermediary structure that provides a sealed interface between the fixed wing and the wing tip device. The follower and guide interlock to create a continuous interface that can be sealed, preventing ingress of contaminants while allowing the oblique cut plane separation to maintain span reduction capability.
Data Source
AI summary
A folding wing having a wing tip device (3) rotatable between flight and ground configurations, about an Euler axis of rotation (11). The wing tip device (3) and a fixed wing (1) are separated along an oblique cut plane (13) passing through the upper and lower surfaces of the folding wing. A rotational joint (15) for coupling the wing tip device (3) to the fixed wing (1) during rotation between the ground and flight configurations. The rotational joint includes a follower (17a) and a guide (17b), one which being fixed relative to the wing tip device and the other being fixed relative to the fixed wing. The follower and guide interlock such as by interlocking rings. The follower is received in the guide such that during rotation between the ground and flight configurations the follower moves along the arcuate path defined by the guide.