Screw Socket Assembly for Tubular Structures

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Solution Overview

Problem

Existing methods for assembling tubular building structures, such as wind turbine towers, face challenges including corrosion at joining points due to moisture ingress and require access from both sides, making them inefficient and prone to structural weaknesses, especially in tall structures where external assembly is difficult or unsafe.

Innovation Solution

The method involves pre-mounting screw sockets with surface treatments at the manufacturing site, allowing for one-sided assembly using bolts, which minimizes corrosion risk and enables assembly from within the structure, using serrated or unserrated screw sockets fastened by press fit, magnets, or adhesive, and employing surface treatments like galvanizing and powder coating to create a sealed outer surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional bolts and nuts are used to join tube sections, then the structure can be assembled without welding, but moisture percolating into the screw connections causes corrosion leading to structural weaknesses

Engineering Contradiction:
Improvestructural integrityVSAvoidcorrosion at joining points
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The screw connection is extracted from the tube wall by using blind sockets that protrude from the outer surface. This allows the screw threads to be located outside the tube wall where they can be properly protected and accessed for tightening, while the tube wall itself remains intact and corrosion-resistant.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The blind sockets are pre-installed in the tube sections before assembly. This preliminary action ensures that the joining points are properly prepared with corrosion protection measures in place before the actual assembly occurs, preventing moisture ingress from the beginning.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If traditional bolt-and-nut connections are used, then assembly can be performed, but access from both sides of the structure is required which is difficult or unsafe for tall structures

Engineering Contradiction:
Improveassembly processVSAvoidaccess from both sides
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

Instead of requiring access from both sides of the tube section to install and tighten bolts, the invention inverts the approach by using blind sockets that protrude from the outer surface. This allows all assembly operations to be performed from the inside of the tube section, eliminating the need for external access and making tall structure assembly safe and feasible.

Inventive Principle:
Principle #13The other way round (Inversion)

3Strength

If tube sections are joined by welding, then strong connections are achieved, but thermal stresses are induced requiring highly skilled people and quality control

Engineering Contradiction:
Improvejoint strengthVSAvoidquality control requirements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention replaces the thermal welding process with a mechanical screw connection system using blind sockets. This substitution eliminates thermal stresses and the associated quality control requirements for skilled welders, while still achieving strong, reliable joints through proper mechanical fastening design.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enhances corrosion resistance and allows for efficient assembly of tall structures without external access, reducing the need for cranes and protecting workers from harsh weather conditions while maintaining structural integrity.

Implementation Method 1

The screw socket may comprise a serrated circumferential surface adapted to provide frictional resistance against rotation of the screw socket after mounting

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The screw sockets may be mounted in holes in the wall elements at the manufacturing site

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2593619B1Method of assembling a tubular building structure by using screw sockets
Publication Date: 2021.12.15 TA TOWERS APS
  • EP2593619B1 patent drawingFigure 1~2
  • EP2593619B1 patent drawingFigure 3~4

AI summary

The present invention relates to a method of assembling a tubular building structure 1 comprising a circumferential wall structure formed from a plurality of wall elements 2,20. The method comprises the step of mutually assembling at least some of the wall elements 2,20 by use of screw sockets 4 mounted in holes in the wall elements 2,20 and bolts. The wall elements may be superposed tube sections 2 arranged on top of each other, and these tube sections 2 may be formed by interconnecting axially extending tube segments 20In some embodiments of the invention, the screw sockets 4 are mounted at the manufacturing site, and the wall elements 2,20 are subsequently transported to the erection site of the tubular building structure 1. Preferably the mutual assembly of the wall elements 2,20 is performable solely by people working inside the tubular building structure 1 fastening the bolts 5 to the pre-mounted screw sockets 4. A method according to the present invention may comprise the following steps: A first surface treatment of at least an outer surface of the wall elements 2,20 and/or the screw sockets 4, insertion of the screw sockets 4 into holes in the wall elements 2,20, and a second surface treatment of at least an outer surface of the wall elements 2,20 with the screw sockets 4 inserted therein. Hereby a sealed outer surface can be obtained whereby the risk of moisture percolating into the screw connections over time and the resulting likely corrosion can be minimised compared to traditional assembly methods by use of ordinary bolt-and-nut connections.