Chain Lock Safety Bolt With Bend-to-Fail Assembly Indication

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Solution Overview

Problem

Existing chain lock safety bolts fail to unambiguously differentiate between correct and incorrect assembly, allowing for potential reuse after incorrect installation, which can lead to failure and safety issues.

Innovation Solution

A safety bolt design featuring a base body with a through-opening, spring rings, and balls, where a leg extending from the spring ring bends if incorrectly inserted, rendering the bolt unusable after incorrect assembly, ensuring clear recognition of correct installation and preventing reuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional locking bolt is used, then the chain lock can be secured, but it cannot unambiguously differentiate between correct and incorrect assembly, allowing potential reuse after incorrect installation

Engineering Contradiction:
Improveassembly identification reliabilityVSAvoidlocking bolt structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses visual indicators (color-coded markings or positional visibility) to indicate correct versus incorrect assembly. The marking on the locking bolt allows immediate visual identification of proper installation orientation, eliminating ambiguity without adding mechanical complexity.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The locking bolt features asymmetric design elements including a specific marking orientation and the positioning of functional components (spring washer, balls, locking element) that only align correctly in one orientation. This asymmetry ensures unambiguous identification of correct assembly while preventing reuse after incorrect installation.

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If the locking bolt allows reuse after incorrect installation, then manufacturing simplicity is maintained, but safety issues arise due to potential failure

Engineering Contradiction:
Improvelocking bolt manufacturing simplicityVSAvoidsafety risk from incorrect assembly
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates preventive measures directly into the locking bolt design: the asymmetric marking and component arrangement prevent incorrect assembly from the outset by making it visually identifiable. This preliminary anti-action eliminates the need for post-assembly verification and prevents safety risks before they can materialize.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The design converts the potential harm of incorrect assembly into a beneficial feature: the asymmetric marking and component positioning that would normally complicate manufacturing actually serve as built-in safety indicators. The very features that differentiate correct from incorrect assembly become the safety mechanism itself.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If the locking bolt components are simplified for easy manufacturing, then production cost decreases, but the ability to provide clear assembly feedback is reduced

Engineering Contradiction:
Improveproduction simplicityVSAvoidassembly correctness detection
Core Design Contradiction:
Ease of manufactureVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs visual markings (color-coded or contrast-marked features) on the locking bolt that are simple to manufacture yet provide immediate and unambiguous feedback on assembly correctness. These markings require minimal additional manufacturing steps while dramatically improving detectability of proper installation.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The asymmetric marking and component positioning are applied locally to specific features of the locking bolt rather than requiring complex changes to the entire structure. This localized approach maintains overall manufacturing simplicity while providing clear assembly feedback at critical locations.

Inventive Principle:
Principle #3Local quality

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 solution provides unambiguous identification of correct assembly, prevents reuse after incorrect installation, enhancing both safety and availability by ensuring the safety bolt is only functional when correctly installed.

Implementation Method 1

The spring washer has at least one leg extending longitudinally along the base body, which bends if the locking bolt is incorrectly inserted into the opening

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3964731B1Safety bolt, chain lock and method for securing a chain lock
Publication Date: 2023.08.30 RUD KETTENFABRIK RIEGER & DIETZ GMBH & CO
  • EP3964731B1 patent drawingFigure 1~2
  • EP3964731B1 patent drawingFigure 3~6
  • EP3964731B1 patent drawingFigure 7~8

AI summary

The invention relates to a locking bolt (16) that can be inserted into an opening (28) formed by the two chain lock arms (12, 14) of a chain lock (10) to prevent them from separating, comprising a base body (30) with a through-opening (32), at least one spring ring (34), at least two balls (36) and a locking element (38) that is inserted into the through-opening (32), wherein an annular groove (54) is provided in a cylindrical surface (59) of the base body (30) in which the spring ring (34) sits, wherein the annular groove (54) is provided with two bores (66) that are aligned with the through-opening (32) and in which the balls (36) sit, and wherein the spring ring (34) has at least one leg (64) extending in the longitudinal direction of the base body (30), which if the locking bolt (16) is incorrectly inserted into the opening (28), it bends.Furthermore, the invention relates to a chain lock (10) for connecting two chains formed from links and to a method for connecting two chains by means of a chain lock (10) and for securing against the chain lock jaws (12, 14) of the chain lock (10) from interlocking by means of a locking bolt (16).