Nut-Locking Assembly With Elastic Washer for Controlled Unlocking

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Solution Overview

Problem

Existing locking devices face difficulties in maintaining effective locking and ease of assembly due to opposing wedge forces and limited angular rotation, making dismantling and assembly challenging, especially under vibrations.

Innovation Solution

A locking device assembly featuring a nut, ring, and washer with deformable tabs and notches, allowing for positive locking by ensuring the ring and nut remain locked through angular configurations, with identical thread pitches and drive surfaces for coordinated rotation, and a radial offset to accommodate sufficient angular range for unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If different pitches are used between the threads of the ring/nut assembly and the screw/nut and screw/ring assemblies, then the ring can rotate freely relative to the nut over a large angle, but the assembly becomes difficult to mount and lock because the rotation angle is limited by the length of the smallest pitch

Engineering Contradiction:
Improverotation freedom of ring relative to nutVSAvoiddifficulty of assembly and locking
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent changes the pitch parameter of the threads to be identical across all three thread assemblies (screw/nut, screw/ring, and ring/nut). This parameter unification allows the ring to rotate freely relative to the nut without being constrained by different pitch lengths, while also simplifying the assembly and locking process by eliminating the complexity of coordinating different pitch specifications.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If finer or wider pitches are used to allow larger rotation angles, then the ring can rotate more freely, but the assembly becomes difficult to mount and lock since the rotation angle is limited by the length of the smallest pitch

Engineering Contradiction:
Improveangular rotation rangeVSAvoidease of assembly and locking
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent standardizes the pitch parameter across all thread assemblies to be identical, which provides adaptability for sufficient rotation range while maintaining ease of assembly and locking. This uniform pitch specification eliminates the operational difficulty that would arise from coordinating different pitch lengths, allowing the device to be mounted and locked efficiently.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the nut and ring are tightly constrained to prevent rotation, then locking is achieved, but the device blocks under very small angles making dismantling or assembly almost impossible

Engineering Contradiction:
Improvelocking effectivenessVSAvoidease of assembly and dismantling
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces a dynamic locking mechanism where the locking elements (such as tabs or protrusions) are designed to engage only after a specific rotation angle is achieved. During assembly, the ring can rotate freely relative to the nut, and only when the predetermined angle is reached do the locking elements engage to secure the position. This dynamic approach ensures reliable locking while maintaining ease of assembly and dismantling, as the locking is automatic and occurs at the appropriate stage.

Inventive Principle:
Principle #15Dynamics

4Reliability

If a positive locking means is added to ensure secure locking, then locking reliability improves, but the device complexity increases due to the additional third part that must be broken or plastically deformed

Engineering Contradiction:
Improvelocking securityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the positive locking means into the existing nut and ring structure, merging the locking function with the primary components rather than adding a separate third part. The locking elements are formed as integral features of the nut or ring, such as tabs that bend or protrusions that engage with corresponding features on the other component. This merging approach maintains locking security while avoiding the increase in device complexity that would result from adding an independent locking component.

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

The solution ensures secure locking and controlled unlocking, maintaining effective torque resistance while simplifying assembly and disassembly, with a visual indication of the locked position and adaptable to various angular ranges for reliable operation.

Implementation Method 1

said at least one tongue being deformable elastically between a rest configuration and a constraint configuration

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3688322B1Nut-locking device and associated assembly unit
Publication Date: 2022.11.09 LISI AEROSPACE
  • EP3688322B1 patent drawingFigure 1~2
  • EP3688322B1 patent drawingFigure 3~4
  • EP3688322B1 patent drawingFigure 5~6

AI summary

The invention concerns a unit (210) for a locking device, comprising: a nut (212) comprising two coaxial taps in opposite directions; and a ring (213); said ring including a third tap (38); the first (18) and third (38) taps being capable of engaging with a single first thread (22); said ring including a second thread (40) capable of engaging with the second tap (20) of the nut. The unit further comprises a washer (214) configured (274) so as to be inserted around one (212) of the nut and the ring, the washer comprising an elastic engagement means (272) for engaging with the other (213) of the ring and the nut in an installation position of the unit, so as to prevent the ring and the nut from rotating relative to each other.