Fiber Rope Shackle With Self-Tightening Noose Structure

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Solution Overview

Problem

Metal shackles used in lifting and towing are heavy, bulky, and difficult for a single person to manually lift and deploy, posing safety and storage challenges, and soft shackles with buttons can be dangerous and unsuitable for heavier loads.

Innovation Solution

A shackle design featuring a flexible elongate member formed into a continuous endless loop with three noose portions, allowing for self-tightening and loosening through a shackle pin, using materials like aramid fibers and UHMwPE to reduce weight and enhance safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal shackles are designed to be strong for heavy load situations, then strength is improved, but weight and bulkiness increase making them difficult to manually lift and deploy

Engineering Contradiction:

ImprovestrengthVSAvoidweight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent changes the material parameter from metal to synthetic fiber (aramid, UHMwPE), fundamentally altering the weight-to-strength ratio. This material substitution enables the shackle to maintain high breaking loads (e.g., 20,000 kg to 600,000 kg) while reducing weight by a factor of 5-10 times compared to traditional metal shackles, directly resolving the contradiction between strength and weight

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The shackle body is constructed from composite synthetic fiber materials combining aramid and UHMwPE (Ultra-High Molecular Weight Polyethylene). This composite structure leverages the high tensile strength of aramid and the low density of UHMwPE to achieve optimal strength-to-weight ratio, enabling the shackle to withstand heavy loads while remaining lightweight and manually deployable

Inventive Principle:

Principle #40Composite materials

2Strength

If metal shackles are designed to be strong for heavy load situations, then strength is improved, but bulkiness increases affecting storage ease

Engineering Contradiction:

ImprovestrengthVSAvoidbulkiness

Core Design Contradiction:

StrengthVSVolume of moving object

Solution Approach 1:

Changing from metal to synthetic fiber material fundamentally alters the volume characteristics. The flexible nature of the rope allows the shackle to collapse into a compact form when not in use, dramatically reducing storage volume while maintaining full strength capacity when deployed, thus resolving the contradiction between strength and bulkiness

Inventive Principle:

Principle #35Parameter changes

3Ease of repair

If soft shackles use a button design to allow rope replacement, then ease of repair is improved, but reliability deteriorates due to accidental opening and inability to handle heavier loads

Engineering Contradiction:

Improveease of repairVSAvoidreliability

Core Design Contradiction:

Ease of repairVSReliability

Solution Approach 1:

The shackle is divided into replaceable components: the shackle body (rope structure) and the shackle pin (metal component). This segmentation allows the rope portion to be replaced independently when worn, maintaining ease of repair, while the robust metal pin provides reliable locking. The design resolves the contradiction by allowing modular replacement without compromising overall system reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shackle transitions from a static button design to a dynamic self-tightening mechanism. When the shackle pin is inserted, the end noose portions automatically tighten around it, creating a secure mechanical lock that prevents accidental opening. This dynamic self-tightening feature maintains reliability while preserving the ability to replace the rope component

Inventive Principle:

Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design provides a lightweight, safer shackle that can be easily handled and stored, effectively securing heavy loads without the risk of catastrophic failure, while maintaining high strength and durability.

Implementation Method 1

using materials like aramid fibers and UHMwPE to reduce weight and enhance safety

Methodology Applied

Scientific EffectHigh-strength fiber material properties:

Implementation Method 2

a contraction or extension of the intermediate noose portion causes a movement of said length of rope through where the elongate member passes through itself, thereby effecting a proportional tightening or loosening of one or each of said end noose portions

Methodology Applied

Scientific EffectMechanical advantage through rope circuit geometry: Mechanical Advantage

Implementation Method 3

a tightening of said end noose portions promotes a contraction of said eyes about said shackle pin and a corresponding coupling of the shackle pin to the shackle body

Methodology Applied

Scientific EffectFriction and mechanical interlocking: Friction

Data Source

PatentUS12359706B2Shackle

Publication Date: 2025.07.15 RIGGING CONCEPTS LTD

AI summary

The present invention relates to a shackle. The shackle comprises a shackle body for use with a shackle pin. The shackle body comprises a flexible elongate member comprising at least one length of rope circuitously formed so that the flexible elongate member passes through itself and defines three sequentially adjacent noose portions Three sequentially adjacent noose portions comprise an intermediate noose portion and two end noose portions at opposing ends of the shackle body.