Grab Hook Shoulder Structure for Loop-Load Stress Distribution

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Solution Overview

Problem

Traditional grab hooks suffer from point-load and shearing issues when using the loop method, leading to premature damage and reduced breaking strength, necessitating a reduction in the working load limit to compensate.

Innovation Solution

The design incorporates a multi-direction support shoulder with an extra wide throat and sloped regions, along with a recess with axially orientated contours, to distribute stress and prevent distortion or shearing of linkages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional grab hooks are used with the loop method, then the hook can securely hold the linkage, but point-load and shearing issues cause premature damage and reduced breaking strength

Engineering Contradiction:

Improvebreaking strengthVSAvoidlinkage durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a recess with axially orientated contours and sloped regions at specific locations within the hook body. These localized structural features concentrate the load distribution function where it is most needed - at the interface between the linkage and hook - while leaving the rest of the hook structure simple and strong.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The recess is segmented into multiple contours (first contour, second contour, etc.) that create distinct load-bearing zones. This segmentation allows different portions of the linkage to be supported by different contours, distributing the overall load across multiple discrete contact points rather than concentrating it at a single point.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the working load limit is reduced to compensate for premature damage, then safety is improved, but the load-bearing capacity of the hook is reduced

Engineering Contradiction:

ImprovesafetyVSAvoidload-bearing capacity

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The recess with its multi-contour structure is pre-formed in the hook body before use. This preliminary structural preparation ensures that load distribution is automatically achieved from the first application of load, preventing the progressive damage that would otherwise occur and necessitate reduced working load limits.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If a narrow throat design is used in grab hooks, then the latch mechanism can effectively close the opening, but the linkage cannot be properly positioned and stress distribution is poor

Engineering Contradiction:

Improvelatch closureVSAvoidthroat width

Core Design Contradiction:

Ease of operationVSShape

Solution Approach 1:

The invention transitions from a simple two-dimensional throat opening to a three-dimensional recess structure with axially orientated contours. This dimensional enhancement allows the throat to maintain its closure effectiveness while providing multiple contours that guide and position the linkage in various orientations, improving both accessibility and stress distribution.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12286997B2Grab hook with shoulder

Publication Date: 2025.04.29 SUNCOR STAINLESS

AI summary

A fastener assembly device includes a body. The body includes top and bottom regions, a channel within the body, and a recess defined in the channel. The recess is wider than any other area of the body.