Ring Flange Screw Tightening Guided by Gap Measurement

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Solution Overview

Problem

In flange connections, especially for wind turbine tower sections, the ring flanges are often not exactly parallel due to manufacturing tolerances, resulting in uneven gaps that existing methods struggle to accurately measure and close uniformly, affecting the assembly preload force and contact between flanges.

Innovation Solution

A method involving a tool carrier with sensors to detect and record gap sizes between ring flanges, determining primary positions for screw connection tightening, and adjusting the tool carrier's position using displacement sensors and control units to ensure uniform tightening, potentially using a laser scanner for precise gap measurement and rollers for support, allowing for controlled movement along the ring flanges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If sequential tightening of screw connections is performed using a self-propelled vehicle with position sensor, then the tightening process can be controlled along the flange circumference, but the method cannot adequately address uneven gap heights between non-parallel flange contact surfaces

Engineering Contradiction:
Improvecontrolled tightening processVSAvoidgap closure uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The gap size is measured and recorded before the tightening process begins. The control system uses this preliminary gap information to determine the tightening sequence, prioritizing screw connections at locations with larger gaps. This preliminary measurement and planning enables the system to adaptively close uneven gaps uniformly during the tightening process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system incorporates gap size measurement as feedback information that influences the tightening sequence decision. The control system continuously references the measured gap sizes to determine which screw connection should be tightened next, creating a closed-loop control that adapts to the actual flange alignment conditions and ensures uniform gap closure.

Inventive Principle:
Principle #23Feedback

2Productivity

If multiple screw connections are tightened simultaneously, then the overall assembly time is reduced, but the uneven gaps between flanges cannot be uniformly closed

Engineering Contradiction:
Improveassembly speedVSAvoidgap closure uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The tightening process applies different sequences and priorities to different local regions of the flange assembly based on locally measured gap sizes. Screw connections at locations with larger gaps are prioritized for tightening, while those at locations with smaller gaps are tightened later. This localized adaptation ensures uniform gap closure across the entire assembly while maintaining efficient productivity.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If the flange contact surfaces are made perfectly parallel, then uniform gap closure is achieved, but manufacturing tolerances make this impossible without adaptive tightening methods

Engineering Contradiction:
Improveflange parallelismVSAvoidassembly complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The system uses the gap measurement information to automatically determine and execute the optimal tightening sequence without requiring external intervention or complex manual adjustment procedures. The control system self-adapts to the actual flange alignment conditions by prioritizing screw connections at locations with larger gaps, enabling uniform gap closure while keeping the assembly process relatively simple.

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

This method ensures a uniform and complete closure of gaps between flanges, increasing the assembly preload force and achieving a gap-free connection by systematically determining and tightening screw connections based on measured gap sizes, thereby improving the axial contact between flange sections.

Implementation Method 1

the size of the gap between the two ring flanges at the respective current position is detected as a gap size value by means of the sensor

Methodology Applied
Scientific EffectLight reflection/Time of flight: LIDAR

Implementation Method 2

the respective current longitudinal position of the tool carrier in relation to the ring is repeatedly recorded as a position value by means of a displacement sensor arranged on the tool carrier

Methodology Applied
Scientific EffectDisplacement measurement: Displacement

Data Source

PatentEP3663034B1Method for tightening screw joints
Publication Date: 2024.02.07 HOHMANN FRANK
  • EP3663034B1 patent drawingFigure 1~4

AI summary

The invention relates to a method for tightening screw connections (10) located at screw positions arranged in series along two annular flanges (2a, 2b) clamped against each other, comprising a tool carrier (3) movable along the ring (2) formed by the annular flanges (2a, 2b) and comprising a tool (4) for tightening the screw connection (10) and a sensor, wherein the tool carrier (3) is moved at least once along the entire length of the ring (2), repeatedly recording the current longitudinal position of the tool carrier (3) relative to the ring (2) as a position value, and the sensor detects the size of the gap between the two annular flanges at the current position as a gap size value and transmits this information to a control and evaluation unit, which stores the individual gap size values ​​together with the respective associated position values ​​as data sets.wherein the control and evaluation unit further determines the largest or an above-average gap size value from the gap size values ​​contained in the data sets and designates the position value assigned to this determined gap size value as a primary position, and wherein the screw connection (10) subsequently tightened by the tool is the one located at the primary position or at a screw position (10) immediately following the primary position in the circumferential direction.