Self-Locking Nut Assembly with Integrated Lock Pin

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Solution Overview

Problem

Conventional nut assemblies are prone to 'backing off' or 'reverse threading,' which can lead to loose wheel ends, potentially causing leaks or breakage, posing safety concerns and requiring additional locking features to inhibit relative motion between the nut and washer.

Innovation Solution

A self-locking nut assembly with a lock pin operatively coupled to both the nut and washer, held by a spring or elastic member, allowing relative movement in the uninstalled configuration and engaging a lock feature in the installed configuration to prevent rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional nut assemblies are used without locking features, then the structure is simple and easy to manufacture, but the nut may back off or reverse thread during use, causing loosening and safety concerns

Engineering Contradiction:
Improveprevention of nut backing offVSAvoidstructure of nut assembly
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the nut and washer into a single integrated component, eliminating the need for separate locking features. The integrated design incorporates locking functionality within the single piece structure, resolving the contradiction by merging multiple functions (fastening and locking) into one component, thus maintaining simplicity while preventing back-off.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single piece nut assembly is designed to automatically prevent back-off through its inherent structural features without requiring additional active locking mechanisms. The design enables the nut to self-lock through its geometry and material properties, eliminating the need for complex external locking systems while maintaining reliability.

Inventive Principle:
Principle #25Self-service

2Reliability

If locking features are added to prevent backing off, then the reliability improves, but the device complexity increases

Engineering Contradiction:
Improveprevention of relative motion between nut and washerVSAvoidnumber of components and locking mechanisms
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the nut and washer into a single integrated component, eliminating the need for separate locking features. The integrated design incorporates locking functionality within the single piece structure, resolving the contradiction by merging multiple functions (fastening and locking) into one component, thus maintaining simplicity while preventing back-off.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single piece nut assembly is used, then the number of components is reduced, but additional locking features are needed to prevent rotation

Engineering Contradiction:
Improvenumber of componentsVSAvoidprevention of rotation during installation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The single piece nut assembly is designed to automatically prevent back-off through its inherent structural features without requiring additional active locking mechanisms. The design enables the nut to self-lock through its geometry and material properties, eliminating the need for complex external locking systems while maintaining reliability.

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 nut assembly from loosening by ensuring secure engagement between the nut and washer, enhancing safety and reliability by maintaining the wheel end securely attached.

Implementation Method 1

a spring or elastic member holds the lock pin to the nut and washer

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3055577B1Lockable single piece nut assembly
Publication Date: 2018.08.22 STEMCO PRODUCTS INC
  • EP3055577B1 patent drawingFigure 1
  • EP3055577B1 patent drawingFigure 2
  • EP3055577B1 patent drawingFigure 3

AI summary

A nut assembly is provided. The nut assembly includes a nut having a bottom extension surface and an intermediate member. The intermediate member includes at least one radially extending slot. The nut assembly also includes a washer having a base and an inner wall. The inner wall has a locking feature. The nut and the washer are operably coupled by a plurality of locking pins. The locking pin slidingly fits in the slot on the intermediate member and engages the locking feature when the nut assembly is in the installed configuration.