Shackle Self-Centering Cross Member

Solution Overview

Problem

Existing shackles with constant diameter closure cross members face challenges in maintaining a 90-degree angle for the eye of a wire or rope, leading to suboptimal load ratings due to additional bending stresses and require numerous sized washers and sleeves for centering, which are prone to loss.

Innovation Solution

A shackle design featuring a closure cross member with a concave shaped center section, matching the diameter of the larger lug, ensures automatic centering and alignment of the load with the shackle's centerline, reducing bending stresses and eliminating the need for multiple sized add-ons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a constant diameter closure cross member is used, then the shackle structure is simple and easy to manufacture, but the eye connection cannot be centered properly and bending stresses increase

Engineering Contradiction:

Improveclosure cross member manufacturing simplicityVSAvoidload alignment and centering accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The closure cross member transitions from constant diameter to variable diameter with a concave center section. The concave section has a smaller diameter that matches the lug hole diameter, creating automatic centering when the cross member is inserted. This local geometric modification enables proper alignment without complex assembly procedures while maintaining manufacturing feasibility.

Inventive Principle:

Principle #3Local quality

2Reliability

If washers or sleeve add-on devices are used to center the eye connection, then centering accuracy is improved, but the device complexity and number of parts increase

Engineering Contradiction:

Improvecentering accuracyVSAvoidnumber of add-on parts

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The centering function previously requiring separate washers or sleeve add-on devices is integrated directly into the closure cross member through the concave center section. This merger eliminates the need for multiple auxiliary parts, reducing device complexity while maintaining reliable centering accuracy. The cross member now performs both its primary closing function and the centering function simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The concave center section of the closure cross member enables automatic self-centering during assembly. When the cross member is inserted through the lug holes, the geometry of the concave section naturally guides and centers the eye connection without requiring external centering devices or complex alignment procedures. The system centers itself through its own geometric features.

Inventive Principle:

Principle #25Self-service

3Reliability

If washers and sleeves are used for centering, then centering is achieved, but the risk of losing small parts increases

Engineering Contradiction:

Improvecentering functionVSAvoidloss of small add-on parts

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The centering function previously requiring separate washers or sleeve add-on devices is integrated directly into the closure cross member through the concave center section. This merger eliminates the need for multiple auxiliary parts, reducing device complexity while maintaining reliable centering accuracy. The cross member now performs both its primary closing function and the centering function simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The concave center section of the closure cross member enables automatic self-centering during assembly. When the cross member is inserted through the lug holes, the geometry of the concave section naturally guides and centers the eye connection without requiring external centering devices or complex alignment procedures. The system centers itself through its own geometric features.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9726255B1Shackle with self centering closure cross member

Publication Date: 2017.08.08 TARRANT PATRICK M

AI summary

A shackle with a closure cross member having a concave cross section is disclosed. The closure cross member is inserted into the lugs at the end of a bail of a shackle such that the concave cross section is disposed between the inner faces of the lugs on the bail. The concave cross section of the closure cross member works to center a wire or rope connected to the shackle closure cross member and ensure that the wire or rope is perpendicular to the centerline of the closure cross member. The concave cross section disposed between the inner faces of the lugs on the bail ensures that the wire or rope connecting a load to the shackle remains normal to the centerline of the closure cross member regardless of the movement or orientation of the load attached to the shackle.