Non-Circular Locking Collar and Washer for Threaded Fastener Rotation Prevention

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Solution Overview

Problem

Existing fastening apparatuses that use keys to prevent rotation of threaded fastening elements can be difficult to remove without damaging components, and keys can shear or fail, leading to hazards and component damage.

Innovation Solution

A fastening apparatus featuring a threaded fastening element with a locking collar and a locking washer that fits within a recess in the component, preventing rotation with a non-circular outer shape and inner contact surfaces, allowing for easy removal without damaging the component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If keys are used to prevent rotation of threaded fastening elements, then rotation prevention is achieved, but removal becomes difficult and component damage may occur

Engineering Contradiction:

Improverotation preventionVSAvoidremoval difficulty

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The locking function is segmented into two parts: a permanent non-circular recess in the component and a removable non-circular collar on the fastening element. The collar can be removed with the fastening element, while the recess remains in the component, enabling easy removal without damaging the component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The locking feature (collar) is extracted from the component and placed on the fastening element instead. This allows the locking mechanism to be removed together with the fastening element, eliminating the problem of keys being difficult to remove or damaging the component.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If keys are used to prevent rotation, then locking is achieved, but keys can shear or fail creating hazards

Engineering Contradiction:

Improvelocking functionVSAvoidkey failure hazards

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The non-circular geometry of the collar and recess creates a self-locking mechanism through geometric constraint. The shapes are designed to prevent rotation without relying on the mechanical strength of a key, eliminating the hazard of key failure.

Inventive Principle:

Principle #25Self-service

3Reliability

If keys are used to prevent rotation, then locking is achieved, but component threads may be damaged when keys fail

Engineering Contradiction:

Improvelocking functionVSAvoidthread damage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The locking function is separated from the component threads by placing the non-circular collar on the fastening element rather than in the component. This protects the component threads from damage that would occur if a key failed while engaged with the component.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS7922433B2Locking fastening apparatus

Publication Date: 2011.04.12 AEROJET ROCKETDYNE OF DE INC

AI summary

In some embodiments fastening apparatus includes a threaded fastening element adapted to be threaded into a hole provided in a first component, the threaded fastening element including a locking collar that is defined by at least one outer peripheral surface, and a locking washer adapted to fit within a recess formed in the component to limit rotation of the threaded fastening element once the element is threaded into the component hole, the washer including an inner opening defined by at least one inner peripheral surface and a non-circular outer shape defined by an outer peripheral surface, the inner opening being adapted to receive the locking collar such that the at least one outer peripheral surface of the collar can contact the at least one inner peripheral surface of the washer.