Shackle Captured Pin Assembly Tool-Free Installation
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Solution Overview
Problem
Existing shackles require tools for installation and removal, and they often lose components, posing risks in hazardous conditions and subsea environments where tool use is difficult or impossible.
Innovation Solution
A shackle with a captured pin assembly featuring a rotating locking clip that moves between locked and unlocked positions, using a split ring retaining spring clip and threaded openings to secure the shackle pin without tools, ensuring all components remain attached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional screw-pin or bolt-type shackles are used, then the shackle pin can be securely fastened, but tools are required for installation and removal which are difficult to use in hazardous conditions
Solution Approach 1:
The shackle pin assembly is designed to be self-retaining through the interaction of the reduced diameter portion, spring clip, and locking groove. The spring clip automatically engages the locking groove when the pin is inserted, and the reduced diameter portion ensures proper positioning without requiring tools for installation or removal
Solution Approach 2:
The spring clip acts as an intermediary element between the shackle pin and the ear opening. It provides the retaining force necessary to secure the pin while allowing tool-free operation. The rotating locking clip serves as another intermediary that provides visual indication and additional retention without requiring tools
2Reliability
If traditional shackles with separate cotter pins or retaining mechanisms are used, then the connection can be secured, but components may become separated and lost in hazardous conditions
Solution Approach 1:
The retaining function is merged into the shackle pin assembly itself through the integrated spring clip and locking groove mechanism. The reduced diameter portion of the pin works in conjunction with the spring clip to provide retention, eliminating the need for separate cotter pins or retaining mechanisms that could become lost
Solution Approach 2:
The spring clip is nested within the ear opening, and the reduced diameter portion of the shackle pin is nested within the spring clip's retained space. This nested arrangement ensures that all components remain contained within the shackle assembly and cannot become separated or lost
3Reliability
If a rotating locking clip is added to prevent component separation, then component retention is improved, but the device complexity increases
Solution Approach 1:
The rotating locking clip serves multiple functions: it provides visual indication of the locked position, acts as an additional retaining mechanism, and can be manipulated to release the spring clip from the locking groove. This multi-functionality justifies the added complexity by providing enhanced reliability without requiring separate components
Data Source
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AI summary
A shackle with captured pin assembly. The shackle includes a pair of opposed legs. A first ear for one of the opposed legs includes an opening therethrough to receive a shackle pin. A recess in the opening receives a spring clip surrounding a shaft of the shackle pin. A second ear for another of the opposed legs is opposed to the first ear. The second ear has an opening therethrough to receive the shackle pin and has an opening with a threaded portion. The shackle pin has a head, a threaded portion engageable with the threaded portion of the second ear opening, and a reduced diameter portion. The rotating retaining clip rotates about an axis parallel to the shackle pin between a locked and an unlocked position.