Nested Locking Thread Fastener With Opposite-Hand Threads

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Solution Overview

Problem

Standard threaded fasteners loosen over time due to vibration and lack adequate anti-tampering features, with existing locking systems often incurring permanent damage during use and requiring frequent reapplication of thread locking compounds.

Innovation Solution

A locking threaded fastener system comprising a first fastener and a second fastener connected by a rotating joint, where the first fastener is axially positioned within the second fastener, with opposite thread handedness, allowing simultaneous counter-rotation to resist loosening and prevent unauthorized removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard threaded fasteners are used, then the fastener can be easily tightened and loosened, but the fastener loosens over time due to vibration

Engineering Contradiction:

Improveresistance to looseningVSAvoidease of tightening and loosening

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The fastener is divided into two separate fastener components (first and second fasteners) with opposite thread handedness that are coupled together through a rotating joint. This segmentation allows each component to rotate independently, enabling the fastener to be tightened and loosened while maintaining resistance to vibrational loosening through the differential rotation capability of the rotating joint.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rotating joint introduces dynamic capability to the fastener system, allowing relative rotation between the first and second fastener components. This dynamic feature enables the fastener to adapt to vibrational forces by permitting controlled rotation, thereby preventing loosening while maintaining ease of operation during intentional tightening and loosening.

Inventive Principle:

Principle #15Dynamics

2Reliability

If thread locking compound is applied to standard fasteners, then locking effectiveness is improved, but the compound is messy and must be reapplied each time the fastener is removed

Engineering Contradiction:

Improvelocking effectivenessVSAvoidmaintenance requirements

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The rotating joint mechanism provides self-contained locking functionality through the mechanical interaction between the first and second fastener components with opposite thread handedness. The system maintains locking effectiveness through its inherent mechanical design rather than requiring external locking compounds, eliminating the need for reapplication after removal and avoiding messiness associated with compounds.

Inventive Principle:

Principle #25Self-service

3Reliability

If existing locking systems are used, then locking effectiveness is improved, but permanent damage is incurred in the tightening and loosening process

Engineering Contradiction:

Improvelocking effectivenessVSAvoidnumber of tightening/loosening cycles

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The rotating joint enables dynamic adjustment between the first and second fastener components during tightening and loosening operations. This dynamic capability allows the fastener to undergo multiple cycles of assembly and disassembly without incurring permanent damage, as the rotating joint accommodates the mechanical stresses and prevents thread damage that would otherwise limit the number of usable cycles.

Inventive Principle:

Principle #15Dynamics

4Object-affected harmful factors

If existing locking fasteners are used, then some anti-tampering features are provided, but adequate anti-tampering protection is not achieved

Engineering Contradiction:

Improvetampering resistanceVSAvoidfastener structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The fastener is segmented into two components with opposite thread handedness coupled by a rotating joint, creating a structurally complex assembly that provides inherent anti-tampering features. The differential thread configuration and rotating joint mechanism make unauthorized removal difficult while maintaining reasonable fastener structure for legitimate applications.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11754112B2Locking thread fasteners

Publication Date: 2023.09.12 SALVUCCI EMANUELE

AI summary

The present specification discloses a locking fastener that includes a first threaded fastener axially positioned within an axial through hole of a second threaded fastener, and captured therein by a rotating joint that permits rotation of the first threaded fastener and the second threaded fastener relative to one another about a common thread axis. In one or more embodiments, the first threaded fastener thread handedness is opposite to the second threaded fastener thread handedness. Additionally disclosed, is a screwdriver tool configured to simultaneously engage and oppositely rotate the first threaded fastener and the second threaded fastener into a mating component having a first mating thread and a second mating thread configured to receive the first threaded fastener and the second threaded fastener, respectively, driven at the same axial advance distance for each turn. Once tightened, the present locking fastener resists loosening and provides a tamper-resistant hold.