Space Frame Node with Cup-Shaped Connectors and Tenons
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Solution Overview
Problem
Existing methods for interconnecting space frame structures, such as in vehicles and buildings, face challenges with stress concentration at weld points and the time-consuming setup of jigs for joining structural members, as well as difficulties in inspecting interior welds.
Innovation Solution
A single-piece node body with cup-shaped connectors and a tenon design that allows for direct attachment of frame members, distributing welds away from high-stress areas and enabling easier inspection, while eliminating the need for jigs and reducing the complexity of the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If hollow castings (lugs or nodes) are used at frame junctions with tubes fitted interiorly, then the need for jigs to hold every element is obviated, but the tubes still require coping to maximize insertion dimension and stress concentration occurs at the point of intersection
Solution Approach 1:
Instead of fitting tubes interiorly into hollow castings as in conventional designs, this patent inverts the approach by having the node body extend outwardly to receive tubes. The cup-shaped connectors with tenons protrude from the node body, allowing tubes to be fitted over the tenons rather than inside hollow cavities. This inversion eliminates the need for coping while distributing stress along the tenon length rather than concentrating it at the intersection point.
Solution Approach 2:
The node body is segmented into multiple cup-shaped connectors, each with its own tenon. This segmentation allows each tube connection to be independently optimized with a tenon that distributes the weld stress along its length, rather than having all tubes converge at a single stress concentration point in the center of a hollow casting.
2Length of moving object
If tubes are coped to maximize insertion dimension into castings, then insertion depth is improved, but stress concentration occurs at the point of intersection and the coping process adds manufacturing complexity
Solution Approach 1:
The patent inverts the conventional approach by having tenons extend outwardly from the node body rather than having hollow castings with interior cavities. Tubes are fitted over the tenons without requiring coping, as the tenon length provides sufficient insertion depth while distributing stress along its length rather than concentrating it at the tube intersection point.
3Manufacturing precision
If jigs are employed to hold tubes while joining, then positioning accuracy is improved, but the setup and use of jigs is time consuming
Solution Approach 1:
The cup-shaped connectors with tenons are pre-formed as integral parts of the node body during manufacturing. This preliminary action eliminates the need for separate positioning jigs during assembly, as the tenons themselves provide the positioning function. Tubes can be directly fitted over the pre-formed tenons, significantly reducing assembly time while maintaining positioning accuracy.
4Strength
If welds are interior to a casting, then structural integrity is improved, but inspection of welds may be difficult or require expensive test equipment
Solution Approach 1:
The patent inverts the conventional hidden weld approach by having tenons extend outwardly from the node body. Welds are applied to the exterior surfaces of the tenons, making them readily accessible for inspection using standard welding inspection techniques. This eliminates the need for expensive non-destructive testing equipment while maintaining structural integrity through proper weld distribution along the tenon length.
Data Source
AI summary
A node for interconnecting frame members of a frame, the node including a single piece node body. A plurality of cup-shaped node connectors are disposed on the node body. Each of the plurality of node connectors include a closed end attached to the node body and an open end opposite the closed end and extending away from the node body. A sidewall extends between and connects the closed end to the open end. A tenon is formed on the open end. The tenon is shaped and sized to fit within a frame member. A transition is formed between the sidewall and the tenon defining a peripheral, radially outwardly facing groove in cooperation with the frame member, the groove shaped and sized to receive a weld.