Balancing Screw Tool for In-Situ Gas Turbine Rotor Access

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Solution Overview

Problem

Balancing rotor discs in assembled gas turbine engines is challenging due to limited access, making it difficult to accurately and reliably position balancing screws, which can lead to inefficiencies and potential damage from vibrations.

Innovation Solution

A tool and method for inserting or removing balancing screws through the inner and outer casings of a gas turbine engine using a tightening body with a holding portion and engagement portion, allowing for controlled and repeatable balancing by aligning inspection holes and using a key-shaped engagement portion to transfer torque to the balancing screw.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a balancing screw is simply dropped through a tube for insertion, then the insertion process is simple, but the screw may be lost into the engine and its position is not reliable

Engineering Contradiction:
Improveinsertion simplicityVSAvoidscrew positioning reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a tube as an intermediary device that guides the balancing screw into the threaded hole. The tube ensures the screw follows a controlled path and is properly positioned, preventing loss into the engine while maintaining simple insertion through the tube mechanism

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If access to rotating components is limited after engine assembly, then the engine structure remains compact and complete, but precision balancing becomes difficult

Engineering Contradiction:
Improveengine assembly completenessVSAvoidbalancing operation accessibility
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent segments the balancing operation into two parts: the tube is inserted through existing access points in the assembled engine, while the balancing screw is then fed through the tube. This segmentation allows balancing to be performed on fully assembled engines without requiring disassembly, maintaining both engine completeness and operational ease

Inventive Principle:
Principle #1Segmentation

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

Enables safe, secure, and repeatable insertion or removal of balancing screws, reducing the risk of loss and ensuring precise balancing of rotor discs in situ, thereby minimizing downtime and maintenance costs.

Implementation Method 1

a key-shaped engagement portion to transfer torque to the balancing screw

Methodology Applied
Scientific EffectTorque: Torque

Data Source

PatentEP2947335B2Screw tool
Publication Date: 2022.11.16 ROLLS ROYCE PLC
  • EP2947335B2 patent drawingFigure 1
  • EP2947335B2 patent drawingFigure 2
  • EP2947335B2 patent drawingFigure 3

AI summary

A tool and method for inserting an externally threaded object into a threaded receiving hole and removing and externally threaded object from the receiving hole. The tool is provided with an outer body that has a holding portion to hold the externally threaded object during insertion or removal. The holding portion may be a thread that corresponds with the thread of the externally threaded object. The tool also has a tightening body inside the outer body that has an engagement portion for engaging a corresponding engageable portion of the externally threaded body. The tightening body is rotated within the outer body to tighten or loosen the externally threaded body. During insertion or removal, the externally threaded body is securely held by the holding portion of the outer body.