Pipe Node Connector Mechanism for Space Frame Assembly

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Solution Overview

Problem

Existing mechanisms for space frame construction face structural safety issues due to large openings in tubular framework members, which reduce ultimate tension and compression resistance, and expose bolts to corrosion, while incomplete threaded assembly can lead to failure under load.

Innovation Solution

A mechanism where the sleeve is rotated to transmit torque to the bolt, ensuring full screwing into the node connector, with a socket set screw confirming engagement, and a design that eliminates openings through the walls of the tubular framework members for improved structural reliability and corrosion protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If large openings are made in the pipe portion for bolt insertion, then ease of assembly is improved, but ultimate tension and compression resistance are reduced

Engineering Contradiction:
Improveease of assemblyVSAvoidultimate tension and compression resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent extracts the bolt insertion function from the pipe wall openings and relocates it to the conical end. The bolt is inserted through the conical end rather than through openings in the pipe portion, eliminating the need for wall openings while maintaining assembly capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The conical end acts as an intermediary element that facilitates bolt insertion without compromising the pipe wall integrity. The conical end provides a dedicated insertion path for the bolt while the pipe wall remains intact and full-strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If longitudinal slotted holes are made through the sleeve walls for pin passage, then ease of assembly is improved, but ultimate compression resistance is reduced and corrosion protection is compromised

Engineering Contradiction:
Improveease of assemblyVSAvoidultimate compression resistance
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent removes the longitudinal slotted holes from the sleeve design. Instead, the pin passes through discrete openings in the sleeve that are positioned to minimize structural compromise and maximize corrosion protection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sleeve is designed with localized openings for pin passage rather than continuous slotted holes. These discrete openings provide the necessary assembly function while maintaining maximum structural strength and corrosion resistance in the remaining sleeve material.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If electroplated coatings are applied to protect bolts against corrosion, then corrosion protection is improved, but hydrogen embrittlement risk increases

Engineering Contradiction:
Improvecorrosion protectionVSAvoidhydrogen embrittlement risk
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent converts the harmful effect of electroplating (hydrogen embrittlement) into a beneficial protective mechanism. By using electroplating to protect the bolt from corrosion while controlling the plating process to minimize hydrogen absorption, the design achieves dual benefits of corrosion protection and reduced embrittlement risk.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the parameters of the electroplating process (such as plating material, plating thickness, and plating conditions) to optimize the balance between corrosion protection and hydrogen embrittlement risk. By controlling these parameters, the design achieves adequate protection while minimizing harmful hydrogen absorption.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If the internal thread length of the node connector is reduced, then manufacturing complexity is reduced, but confirmation of complete bolt engagement becomes difficult

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidconfirmation of complete engagement
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent incorporates a feedback mechanism through the pin and sleeve assembly that provides tactile and visual confirmation of complete bolt engagement. When the bolt is fully screwed in, the pin reaches a specific position in the sleeve, providing clear feedback to the assembler that engagement is complete.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The design allows the assembly itself to confirm its own completeness through the mechanical interaction between the pin, sleeve, and bolt. The geometry of the components ensures that full engagement is self-verifying without requiring external measurement or inspection tools.

Inventive Principle:
Principle #25Self-service

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 provides a reliable, aesthetically pleasing, and economical connection that ensures the space frame can carry tension and compression loads without thread stripping, allowing for wider span structures and improved corrosion resistance.

Implementation Method 1

the sleeve is rotated to transmit torque to the bolt, ensuring full screwing into the node connector

Methodology Applied
Scientific EffectTorque transmission: Torque

Implementation Method 2

tension from the pipe to the node connector, and conversely, is transmitted through the bolt

Methodology Applied
Scientific EffectTension: Tension

Implementation Method 3

compression is transmitted through the sleeve

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP1997972B1An improved mechanism for the connection of a pipe to a node of a three-dimensional structure
Publication Date: 2012.12.26 GAMANIS GEORGE A
  • EP1997972B1 patent drawingFigure 1
  • EP1997972B1 patent drawingFigure 2
  • EP1997972B1 patent drawingFigure 3

AI summary

An improved mechanism (12) for the connection of a pipe (9) to a node connector (1) of a three-dimensional structure includes: a bolt (8) with a pin (4); a sleeve (3) with a radial threaded hole (20) and two longitudinal grooves (14); a socket set screw (2) screwed through the radial threaded hole (20); a conical end (7) fixed to the pipe (9). The bolt (8) has a radial groove (18) between the pin (4) and the bolt head (19). The radial groove (18) and the radial threaded hole (20) have the same circumferential position; and the same longitudinal position exactly when the sleeve (3) and the bolt head (19) are in contact with the corresponding bearing surfaces (28,29) of the conical end (7). The problem of the confirmation, that the bolt (8) is completely screwed into the node connector (1), is solved; and the probability of encountering environmentally induced cracking in the bolt (8) is eliminated.