Self-Locking Threaded Plug Ratchet Ring for Anti-Rotation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing self-locking threaded assemblies in gas turbine engines lack a simple, robust, and reusable anti-rotation feature that is easy to manufacture and maintain, and often require special tools or knowledge to operate.

Innovation Solution

A self-locking plug assembly featuring a ratchet ring with flexible fingers that engage polygonal sides, combined with a biasing means like a coil spring and an annular retaining ring, provides double anti-rotation protection without the need for special tools, using a design that is simple, robust, and easy to handle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex locking mechanisms with multiple components are used, then anti-rotation protection is improved, but device complexity increases

Engineering Contradiction:
Improveanti-rotation protectionVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the locking function and anti-rotation function into a single integrated mechanism. The ratchet ring with flexible fingers provides both locking (preventing loosening) and anti-rotation protection simultaneously, eliminating the need for separate locking mechanisms and reducing overall device complexity while maintaining double protection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ratchet ring assembly serves multiple functions: it provides locking action through the flexible fingers engaging the polygonal head, prevents rotation through the ratcheted outer profile, and maintains constant engagement through the biasing means. This multi-functional design reduces the number of components needed while achieving comprehensive protection

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple movable elements are used for locking, then self-locking capability is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improveself-locking capabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The locking mechanism is segmented into distinct functional elements: the ratchet ring with flexible fingers, the biasing means, and the polygonal head. Each segment performs a specific function and can be manufactured independently using standard machining processes, simplifying production while maintaining the self-locking capability through their coordinated interaction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible fingers are designed with specific geometric parameters (width, thickness, engagement angle) that allow them to provide locking force through elastic deformation. By optimizing these parameters, the mechanism achieves reliable self-locking with simple manufacturing processes, avoiding complex assembly procedures

Inventive Principle:
Principle #35Parameter changes

3Reliability

If robust locking mechanisms are used, then reliability is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvelocking reliabilityVSAvoidoperational simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism is designed to be self-actuating through the biasing means that automatically maintains engagement between the flexible fingers and the polygonal head. The system requires no external power source, adjustment, or special operational knowledge - the mechanical elements self-regulate to maintain secure locking and anti-rotation protection throughout operation

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

The solution effectively prevents the self-locking plug from loosening or falling out during engine operation, ensuring secure sealing and easy maintenance, while being adaptable for various applications beyond gas turbine engines.

Implementation Method 1

a biasing means, such as a coil spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a ratchet ring with flexible fingers that engage polygonal sides

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP3421823B1Self-locking threaded article with polygonal head and ratchet ring assembly
Publication Date: 2021.05.26 GENERAL ELECTRIC CO
  • EP3421823B1 patent drawingFigure 1
  • EP3421823B1 patent drawingFigure 2
  • EP3421823B1 patent drawingFigure 3

AI summary

A self-locking plug assembly includes ratchet ring (16) circumscribing body (12) having centerline (18) and shank (90) having a threaded top portion. Flexible fingers (22) spiral away from periphery of ratchet ring (16) to engage polygonal sides (28) of polygonal sided ring attached to body (12). Hooks (31) may extend radially outwardly and downwardly from periphery of ratchet ring (16). Spring (56) around polygonal portion of body rests on ratchet ring (16). Annular retaining ring (58) snapped into annular groove in body compresses spring (56). Hooks (31) may engage notches in the upper wall. Alternatively, hooks may include paws extending inwardly from downwardly extending legs of hooks and into the pockets and engaging upper pocket walls to axially secure the ratchet ring. Body may be borescope plug with a lower end of shank conforming to lower port opening in upper wall. Alternatively, flexible fingers extend outwardly from radially outer rim of ratchet ring and engage polygonal sides of inner side of polygonal sided ring circumscribing ratchet ring.