Self-Actuating Lock Nut With Snap Ring
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Solution Overview
Problem
Conventional screws and nuts tend to loosen due to vibration or fluid exposure, as they lack effective mechanisms for secure locking without additional washers.
Innovation Solution
A self-locking hex nut assembly with a cylindrical sleeve and snap ring mechanism that engages threads of different types, requiring specific torque sequences to transition from a stowed to a deployed position, enhancing frictional locking and resisting rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional screws and nuts are used without additional washers, then the device complexity is reduced, but the reliability of the locking mechanism deteriorates due to loosening from vibration or fluid exposure
Solution Approach 1:
The patent combines multiple locking functions into a single integrated nut assembly. The self-locking nut incorporates a locking mechanism with locking elements that engage with the screw threads, eliminating the need for separate flat washers, tension washers, or split lock washers. This merging of functions reduces component count while maintaining reliable vibration-resistant locking through the integrated locking elements that prevent both rotation and prying loose
Solution Approach 2:
The locking mechanism is nested within the nut structure itself. The locking elements are positioned inside the nut's internal geometry, with some locking elements engaging the screw threads from the interior. This nested arrangement allows the locking function to be embedded within the fastener assembly without adding external components, reducing overall device complexity while ensuring reliable locking
2Reliability
If a self-locking mechanism with multiple thread types and torque requirements is implemented, then the reliability of the locking mechanism is improved, but the ease of operation deteriorates due to specific torque sequences required
Solution Approach 1:
The locking mechanism utilizes dynamic torque characteristics where the torque requirement changes during the tightening process. The locking elements are designed to engage at specific torque thresholds, creating a progressive locking sequence. As torque is applied, different locking elements engage at different stages, providing progressive stabilization. This dynamic behavior ensures reliable locking while still allowing straightforward installation with a standard torque application
Solution Approach 2:
The locking mechanism operates autonomously during the tightening process without requiring operator intervention or knowledge of specific torque sequences. As torque is applied to the fastener, the locking elements automatically engage with the screw threads at the appropriate stages based on the torque level. The mechanism self-regulates the locking sequence through its mechanical design, eliminating the need for the operator to follow complex torque procedures while ensuring reliable locking
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 assembly provides a secure, vibration-resistant locking mechanism without additional washers, ensuring the hex nut remains fixed in place by increasing torque and friction between threads, effectively preventing loosening.
Implementation Method 1
causing the first set of threads to lock against the second set of threads via an increase in friction
Implementation Method 2
The reaction between these sets of threads is transmitted to the third set of thread causing additional friction against the fourth set of threads
Data Source
AI summary
The present invention relates to an assembly of a self-locking hex head screw and a self-locking hex nut that use parallel screw threads of one or various types that lock against each other upon applying a torque. The resulting counteracting torque forces provided by the screw thread types are further enhanced by applying a physical lock using press fit surfaces on the nut and finally when a snap ring is deployed to that prevent these threads from prying loose later on.