Chain Lock Fastening Mandrel Anti-Torque Design

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Solution Overview

Problem

Existing chain lock designs face challenges in permanently attaching a chain end link to a securing part in a simple and reliable manner, as they are either complex to manufacture or vulnerable to being unscrewed under torque.

Innovation Solution

A chain lock design featuring a chain end link with a fastening mandrel, where the mandrel's insertion section has a non-circular cross-section extension that fits form-fittingly into a receiving opening of the securing part, allowing for secure attachment through radial pressing, pin engagement, or welding, effectively preventing twisting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a crimp connection is used to attach the chain end link to the locking component, then the manufacturing complexity is reduced, but the connection becomes vulnerable to being unscrewed under high torque

Engineering Contradiction:
Improvemanufacturing complexityVSAvoidresistance to unscrewing under torque
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The fastening mandrel features a non-circular cross-section (square, rectangular, or polygonal) that creates an asymmetric fit within the receiving opening. This asymmetric geometry prevents rotational movement of the chain end link relative to the locking component, eliminating the vulnerability to unscrewing while maintaining a relatively simple crimp connection manufacturing process

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If fastening pins are positioned within a circumferential groove to allow rotational connection, then the chain end link can rotate relative to the locking element, but the manufacturing precision requirements increase significantly

Engineering Contradiction:
Improverotational freedomVSAvoidpositioning precision of fastening pins
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The non-circular cross-section of the fastening mandrel (square, rectangular, or polygonal shape) provides inherent rotational positioning without requiring precise circumferential grooves. The asymmetric geometry naturally guides and constrains the mandrel's orientation during insertion, eliminating the need for high-precision groove positioning while still allowing the chain end link to rotate relative to the locking component

Inventive Principle:
Principle #4Asymmetry

3Ease of manufacture

If a simple crimp connection is used without additional anti-rotation features, then the manufacturing process is simplified, but the connection fails to absorb high torque effectively

Engineering Contradiction:
Improvesimplicity of connectionVSAvoidtorque absorption capacity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The non-circular cross-section of the fastening mandrel (square, rectangular, or polygonal) provides inherent anti-rotation capability that significantly increases torque absorption capacity. This asymmetric geometry creates mechanical interlocking with the receiving opening, allowing the simple crimp connection to withstand high torque loads without requiring complex additional anti-rotation features

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3216954B1Chain lock
Publication Date: 2020.12.30 ABUS AUGUST BREMICKER SOEHNE KG
  • EP3216954B1 patent drawingFigure 1
  • EP3216954B1 patent drawingFigure 2
  • EP3216954B1 patent drawingFigure 3

AI summary

A chain lock comprises at least one locking element and a chain permanently attached at one end to the locking element. The chain has a chain end link with a fastening pin, wherein an insertion section of the fastening pin is inserted into a receiving opening of the locking element, the insertion section of the fastening pin having a projection with a non-circular cross-section at its end. The receiving opening of the locking element has a receiving section in which the projection of the fastening pin is received, at least substantially, in a form-fitting manner.