Aircraft Wing Tip Joint Combining Tension and Pinned Lug Mechanisms
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Solution Overview
Problem
The existing tension joints used to attach wing tip devices to aircraft wings face difficulties in efficiently distributing higher aerodynamic loads and moments, particularly due to the limited attachment area and increased weight of the devices, which complicates assembly and maintenance.
Innovation Solution
A combination joint comprising a tension joint and a pinned lug joint is used, where the ribs have abutment surfaces and lugs that are interleaved with pins to efficiently transfer complex loads and moments, with the tension joint nearest the upper wing cover and the pinned lug joint nearest the lower wing cover, optimizing load distribution and weight constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a tension joint is used to attach the wing tip device, then the attachment is simple, but the load distribution is insufficient for higher aerodynamic loads
Solution Approach 1:
The patent combines a tension joint and a pinned lug joint into a single integrated attachment system. The tension joint components (abutment surfaces, tension bolts) work together with the pinned lug joint components (lugs with holes, pins) to create a hybrid connection that leverages the load-distributing capability of the tension joint and the moment-resisting capability of the pinned lug joint, thereby achieving superior load distribution for high aerodynamic loads while maintaining reasonable structural complexity
Solution Approach 2:
The joint utilizes composite construction by integrating two different joint types (tension and pinned lug) into a unified attachment system. This composite approach allows the structure to exploit the complementary strengths of each joint type: the tension joint's simplicity and the pinned lug joint's ability to handle complex load combinations, resulting in an optimized attachment system
2Strength
If the attachment area is increased to distribute higher loads, then the load distribution improves, but the weight of the wing tip device increases
Solution Approach 1:
The patent applies local quality by concentrating the load-bearing functions in specific localized features: the abutment surfaces for tension loading, the lugs with holes for pinned connection, and the pins themselves for moment resistance. This localized reinforcement allows efficient load distribution without requiring a general increase in the overall size or weight of the wing tip device structure
3Strength
If the weight of the wing tip device is increased to handle higher loads, then the load capacity improves, but the handling and maintenance difficulty increases
Solution Approach 1:
The attachment system is segmented into distinct functional components: the wing tip device with its integrated lugs and abutment surfaces, the pins for connection, and the tension bolts. This segmentation allows the heavy wing tip device to be designed with built-in attachment features rather than adding separate heavy mounting structures, and enables maintenance personnel to work with individual components (such as removing just the pins) rather than handling the entire heavy assembly
Data Source
AI summary
A joint including first and second rib components, the first rib having an abutment surface and a plurality of lugs disposed adjacent to the abutment surface; and the second rib having an abutment surface and a plurality of lugs disposed adjacent to the abutment surface, wherein the abutment surfaces of the respective ribs are abutting and joined with a tension joint, and wherein the lugs are pinned to form a pinned lug joint by aligning respective holes in the plurality of lugs such that the lugs of the first and second ribs are interleaved and have one or more pins passing through the aligned lug holes. The joint may be used for attaching a wing tip device to the outboard end of an aircraft wing.