Self-Locking Threaded Fastener for Vibration-Resistant Assembly

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Solution Overview

Problem

Existing threaded fasteners in high vibration or safety-critical environments risk loosening without additional locking parts, increasing complexity and cost.

Innovation Solution

A threaded fastener design with inward and outward threads and a compressible part that secures the parts axially by applying a preload when the threads disengage, eliminating the need for additional locking elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional locking parts (locking wire or clip) are used to prevent fastening parts from unthreading, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefastening securityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the fastening function and the locking function into a single integrated threaded fastener. The inwardly extending thread on one fastener engages with the outwardly extending thread on the other fastener, and the compressible part provides automatic locking through axial preload, eliminating the need for separate locking wires or clips.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The threaded fastener is designed to automatically secure itself through the interaction of the inwardly and outwardly extending threads combined with the compressible part. When the fasteners are assembled, the compressible part automatically applies axial preload that locks the threads against unthreading, without requiring additional locking parts or special tools.

Inventive Principle:
Principle #25Self-service

2Reliability

If additional locking parts are used to secure fastening, then reliability is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improvefastening securityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the fastening function and the locking function into a single integrated threaded fastener. The inwardly extending thread on one fastener engages with the outwardly extending thread on the other fastener, and the compressible part provides automatic locking through axial preload, eliminating the need for separate locking wires or clips.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If additional locking parts and special tools are used for fastening, then reliability is improved, but productivity deteriorates

Engineering Contradiction:
Improvefastening securityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The threaded fastener is designed to automatically secure itself through the interaction of the inwardly and outwardly extending threads combined with the compressible part. When the fasteners are assembled, the compressible part automatically applies axial preload that locks the threads against unthreading, without requiring additional locking parts or special tools.

Inventive Principle:
Principle #25Self-service

4Reliability

If additional locking parts are used to prevent fastening loosening, then reliability is improved, but cost increases

Engineering Contradiction:
Improvefastening securityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent combines the fastening function and the locking function into a single integrated threaded fastener. The inwardly extending thread on one fastener engages with the outwardly extending thread on the other fastener, and the compressible part provides automatic locking through axial preload, eliminating the need for separate locking wires or clips.

Inventive Principle:
Principle #5Merging (Combining)

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

Provides secure fastening without additional parts or tools, reducing complexity and cost while maintaining stability against vibrations.

Implementation Method 1

the compressible part loads the inwardly extending thread axially into abutment with the outwardly extending thread to secure the first and second threaded parts axially together

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4421334B1Threaded fastener
Publication Date: 2025.09.03 GOODRICH ACTUATION SYST
  • EP4421334B1 patent drawingFigure 1~2
  • EP4421334B1 patent drawingFigure 3~4

AI summary

A threaded fastener comprising a first threaded part (1) defining an axis, A, from a first end (111) to a second end (112) thereof, the threaded part having a radially inwardly extending thread along a portion (11) thereof between the first and the second end and a non-threaded portion (12) between the thread and the second end, and a second threaded part (2) defining an axis from a first end (211) and a second end (212) thereof and having a radially outwardly extending thread (21) along a portion thereof between the first and the second end and a non-threaded portion between the thread and the first end, the fastener further comprising a compressible part (13, 300) arranged to provide an axial load to one of the first and the second threaded parts when the parts are fastened together. The first threaded part is arranged to be fastened around and to the second threaded part by rotating the inwardly extending thread of the first threaded part along the outwardly extending thread of the second threaded part until the inwardly extending thread and the outwardly extending thread no longer engage and the inwardly extending thread lies along the non-threaded portion of the second threaded part, and wherein the compressible part is preloaded such that when the inwardly extending thread and the outwardly extending thread no longer engage and the inwardly extending thread lies along the non-threaded portion of the second threaded part, the compressible part loads the inwardly extending thread axially into abutment with the outwardly extending thread to secure the first and second threaded parts axially together.