Locking Shackle Pin With Rotating Tab Keyhole Retention

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Solution Overview

Problem

Conventional shackles with clevis pins are inconvenient to use without tools and may not be secure enough, as they rely on threaded nuts or cotter pins.

Innovation Solution

A locking shackle and pin design featuring an entry eyehole with a non-linear insertion channel and a locking eyehole with a keyhole that engages a protruding locking tab, requiring axial rotation and a biasing mechanism for secure locking and easy release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a threaded nut or cotter pin is used to secure the clevis pin, then the pin can be secured to the shackle, but the operation becomes inconvenient without tools or less secure

Engineering Contradiction:

Improvesecurity of pin attachmentVSAvoidconvenience of pin installation and removal

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The pin head includes an integrated locking tab that automatically engages with a locking keyhole in the shackle when the pin is inserted. This self-locking mechanism eliminates the need for separate locking devices like nuts or cotter pins, and no tools are required for installation or removal. The user simply inserts the pin, the tab engages the keyhole to secure it, and pulls the tab to release for removal.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The locking function is merged into the pin itself by integrating the locking tab as part of the pin head structure. This combines the fastening function and the locking function into a single component, eliminating the need for separate locking mechanisms and simplifying the overall assembly.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If a simple insertion hole is used, then the pin can be easily inserted, but the pin can fall out unintentionally

Engineering Contradiction:

Improveease of pin insertionVSAvoidprevention of unintentional pin removal

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The locking keyhole in the shackle is designed with an asymmetric shape that matches the locking tab on the pin. The keyhole has a specific geometry that allows the tab to engage securely in one orientation but prevents removal unless the tab is deliberately manipulated. This asymmetric design ensures the pin cannot fall out unintentionally while maintaining ease of intentional insertion and removal.

Inventive Principle:

Principle #4Asymmetry

3Ease of operation

If a non-linear insertion channel is used in the entry eyehole, then the locking tab can pass through during insertion, but the channel complexity increases

Engineering Contradiction:

Improveability of locking tab to pass through during insertionVSAvoidcomplexity of insertion channel

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The non-linear insertion channel in the entry eyehole is designed with a curved path that guides the locking tab smoothly from the entry side to the interior of the shackle. The curved channel allows the tab to rotate or follow a curved trajectory during insertion, enabling the tab to clear the entry opening and engage the locking keyhole without requiring complex mechanical guides or multiple components.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS11808324B2Locking shackle and pin

Publication Date: 2023.11.07 CLARKE GRAHAM

AI summary

A locking shackle for use with a pin having a protruding locking tab. The shackle defines (a) an entry eyehole has a non-linear insertion channel through which the locking tab may pass; and (b) a locking eyehole having an insertion channel through which the locking tab may pass, and a locking keyhole which releasably engages the locking tab when the pin is fully inserted into the shackle.