Centering Bolt With Positioning Arms For Gas Turbine Alignment

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Solution Overview

Problem

Gas turbine engines face challenges in maintaining accurate alignment and repeatability due to variability in bolt placement within clearance holes, leading to misalignment and unreliable data from instrumentation.

Innovation Solution

The introduction of positioning arms on bolts that extend to contact the inner diameter of clearance holes, with a spacer and spring mechanism to ensure centering and alignment, allowing for precise installation and repeated accuracy across multiple installations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional bolts are used without positioning features, then the device complexity is low, but the manufacturing precision and alignment accuracy deteriorate due to variability in bolt placement within clearance holes

Engineering Contradiction:
Improvebolt placement accuracyVSAvoidbolt structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The bolt is segmented into a screw portion and a separate positioning arm assembly. The positioning arms can be detached and reattached, allowing for precise alignment functionality while maintaining a relatively simple bolt structure. This segmentation enables the bolt to provide centering features without significantly increasing overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The positioning arms are pre-configured with specific geometries (such as tapered surfaces or predetermined angles) that automatically guide the bolt into proper alignment with the clearance hole before final tightening. This preliminary positioning action ensures accurate bolt placement without requiring complex adjustment mechanisms during installation.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If positioning arms with spring mechanisms are added to ensure centering, then the alignment accuracy improves, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvealignment accuracyVSAvoidbolt mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The spring mechanism is designed to automatically exert forcing on the positioning arms to maintain contact with the clearance hole walls. This self-regulating mechanism ensures consistent centering without requiring external adjustment or complex control systems, thereby improving alignment accuracy while limiting the increase in device complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If multiple positioning arms are used to prevent floating, then the stability and repeatability of bolt placement improve, but the manufacturing precision requirements and device complexity increase

Engineering Contradiction:
Improveinstallation repeatabilityVSAvoidnumber of positioning components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The positioning arms are designed with specific local geometries (such as tapered surfaces at specific angles) that are optimized for their centering function. This localized quality enhancement allows multiple positioning arms to work together effectively without requiring all components to be of high precision throughout, thereby improving installation repeatability while managing manufacturing complexity.

Inventive Principle:
Principle #3Local quality

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 solution enhances the accuracy and repeatability of bolt placement, improving engine efficiency, measurement accuracy, and data integrity by ensuring consistent alignment of bolts within clearance holes, thereby addressing the variability issues in existing technologies.

Implementation Method 1

a spring that biases at least one of the positioning arms towards the spacer

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3252322B1Centering bolt
Publication Date: 2020.09.23 RTX CORP
  • EP3252322B1 patent drawingFigure 1
  • EP3252322B1 patent drawingFigure 2A
  • EP3252322B1 patent drawingFigure 2B

AI summary

Aspects of the disclosure are directed to a bolt (252) comprising a body (302) having a head (434), a circumferential sidewall (440), a central bore (446) extending at least a portion of a length of the bolt (252), and a plurality of slots (608) extending through the sidewall (440) from the bore (446), a plurality of positioning arms (312) at least partially located within an interior of the bolt (252), and a screw (308) seated within the head (434), where a position of the screw (308) within the head (434) controls an extent to which the plurality of the positioning arms (312) are extended through the sidewall (440).