Tubular Profile Node Structure with Thread-Engaged Tool-Free Assembly
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Solution Overview
Problem
Existing solutions for assembling structures using tubular profiles and nodes are plagued by the need for tools, inadequate finish quality, and complex manufacturing processes, which result in structures that are not robustly or securely fastened.
Innovation Solution
The solution involves designing nodes with arms that have polygonal cross-sections with screw threads on beveled corners, which can be easily inserted into tubular profiles with internal square shapes. This configuration allows for secure fastening without tools, by simply rotating the node and tubular profile relative to each other by no more than 45°.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screws or securing means are used to join tubular profiles to nodes, then the joint is secure, but tools are required and the finish is defective with visible heads
Solution Approach 1:
The patent replaces the traditional screw-threading mechanical system with a press-fit interference system. The arms of the node are designed with dimensions that create interference fit when inserted into the tubular profiles, eliminating the need for screws, bolts, or other securing means that require tools and leave visible heads.
Solution Approach 2:
The node arms are designed to automatically secure themselves within the tubular profiles through interference fit. The dimensions of the arms (e.g., 24mm x 24mm square cross-section) are specifically chosen to create sufficient friction and mechanical interlocking with the internal dimensions of the tubular profiles (e.g., 26mm x 26mm), allowing the structure to assemble without external tools or additional securing elements.
2Ease of operation
If inserts are threaded into tubular profiles and nodes are threaded to inserts, then no tools are needed, but threading takes considerable time
Solution Approach 1:
The patent extracts and eliminates the intermediate threaded insert component from the assembly system. Instead of using tubular profiles with internal threads requiring time-consuming threading operations, the design uses smooth-bored tubular profiles that directly receive the node arms through press-fit interference, dramatically reducing assembly time while maintaining tool-free operation.
Solution Approach 2:
The patent changes the dimensional parameters of the node arms and tubular profile interiors to create optimal interference fit conditions. By carefully selecting dimensions (e.g., 24mm arm vs. 26mm profile interior), the system achieves secure fastening through friction and mechanical interlocking without requiring threading operations, thus improving assembly speed.
3Ease of operation
If press-fit is used with interference, then no tools are needed, but the fastening is not sufficiently robust and secure
Solution Approach 1:
The patent employs composite structural design where the node arms and tubular profiles work together as a composite system. The node arms with specific cross-sectional dimensions (e.g., 24mm x 24mm) combined with tubular profiles of matching dimensions (e.g., 26mm x 26mm internal) create a composite fastening system that leverages both friction and mechanical interlocking for robust securement.
Solution Approach 2:
The patent utilizes the geometric relationship between the square cross-sections of the node arms and the circular/rounded internal geometry of the tubular profiles. This geometric interaction creates multiple contact points and distributes stresses effectively, enhancing the robustness of the press-fit connection while maintaining smooth insertion without tools.
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
This approach eliminates the need for tools and complex manufacturing processes, providing a robust, secure, and quick assembly method for structures made from tubular profiles and nodes, while maintaining a clean and aesthetically pleasing finish.
Implementation Method 1
each arm (1.2) has bevels (1.2.3) determined at its free end to open and facilitate the entry of each arm (1.2) into its respective tubular profile (2). In addition, and with regard to each of the corners of this area with a square edge, there is a bevel with a screw thread; so that four external bevelled sections are determined along the arm
Implementation Method 2
This configuration allows for secure fastening without tools, by simply rotating the node and tubular profile relative to each other by no more than 45°
Implementation Method 3
each arm (1.2) has bevels (1.2.3) determined at its free end to open and facilitate the entry of each arm (1.2) into its respective tubular profile (2)
Data Source
AI summary
A structure for determining shelves and items of furniture, formed by nodes (1) and tubular profiles (2). Each node (1) has at least two arms (1.2) fitted and fastened inside the ends of each section of tubular profile (2), which is a single-body piece along the entire inside of an internal shape (2.1) with a square external edge. Each arm (1.2) of the node (1) has a part (1.2.1) corresponding to the internal square shape (2.1) with a square polygonal edge, the corners have bevels along the length with screw threads (1.2.2) extending parallel to the longitudinal axis of each arm, such that by inserting each arm (1.2) into a tubular profile (2) and rotating relative to one another, the crests of the screw threads (1.2.2) engage against the internal faces of walls (2.2) of the internal square shape (2.1), fastening each node (1) to a respective tubular profile (2).