Reusable Anti-rotation Lock for Gas Turbine Nosecone

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Solution Overview

Problem

Conventional locks used in gas turbine engines for securing the nosecone to the inlet case are single-use, requiring replacement each time the nosecone is disconnected for maintenance, leading to inefficiencies and increased costs.

Innovation Solution

A reusable lock design featuring an annular ring with a protrusion and a tab having a ramped and angled circumferential end, which resists rotation by engaging with detents on the inlet case, allowing for multiple uses by returning to its original position after disengagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-use lock is used to secure the nosecone to the inlet case, then the reliability of the connection is improved, but the productivity and maintenance efficiency deteriorate due to requiring replacement after each disconnection

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmaintenance efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The lock is designed to be reusable through an elastic tab that returns to its original position after disengagement, allowing the lock to be recovered and reused multiple times instead of being discarded after single use

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The tab is designed with elastic properties allowing it to dynamically change position - deforming during engagement/disengagement and returning to original position for reuse, transforming a static single-use component into a dynamic reusable one

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If a single-use lock is used to prevent unwanted rotation, then the stability of the connection is improved, but the loss of time increases due to replacement requirements during maintenance

Engineering Contradiction:
Improveconnection stabilityVSAvoidmaintenance time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The lock maintains connection stability through its engagement mechanism while being recoverable for reuse, eliminating the time loss associated with replacing locks during maintenance operations

Inventive Principle:
Principle #34Discarding and recovering

3Productivity

If a reusable lock with elastic tab is used, then the productivity is improved by allowing multiple uses, but the device complexity increases due to the elastic tab and ramped surface mechanism

Engineering Contradiction:
Improvemaintenance efficiencyVSAvoidlock structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The lock is segmented into distinct functional components - the annular ring for engagement, the elastic tab for reversible deformation, and the ramped surface for controlled disengagement - allowing complexity to be distributed and managed

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If the tab is designed with ramped and angled circumferential ends, then the ease of operation is improved by allowing controlled disengagement, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvedisengagement easeVSAvoidtab geometry precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The ramped and angled surfaces are pre-configured during manufacturing to guide the disengagement process, performing the complex geometric alignment in advance rather than requiring high precision during operation

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3348785B1Anti-rotation lock for threaded in place nosecone or spinner
Publication Date: 2021.11.17 RTX CORP
  • EP3348785B1 patent drawingFigure 1
  • EP3348785B1 patent drawingFigure 2A
  • EP3348785B1 patent drawingFigure 2B~2C

AI summary

A lock (104; 204) for securing a nosecone (64; 200) having first threading (102; 202) to an inlet case (66; 250) having second threading (115; 253) and for use with a gas turbine engine (20) having an axis (A-A') includes an annular ring (106; 206) designed to be positioned about the first threading (102; 202). The lock (104; 204) also includes a tab (108; 208) extending radially from the annular ring (106; 206), and having a ramped circumferential end (110; 211) and an angled circumferential end (112; 213) such that the ramped circumferential end (110; 211) passes over a detent of the inlet case (66; 250) in response to the nosecone (64; 200) being fastened to the inlet case (66; 250) and the angled circumferential end (112; 213) engages with the detent (114; 252) to resist unfastening of the nosecone (64; 200) from the inlet case 66; 250).