Chain Shortening Claw With Rotating Safety Pin Lock

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Solution Overview

Problem

Existing chain shortening claws require excessive force to insert or remove chain links, and the securing mechanisms are complex, making operation difficult.

Innovation Solution

A chain shortening claw with a safety pin that can reversibly displace against a spring force and rotate, allowing for reduced axial movement and improved securing performance, enabling easier insertion and removal of chain links with a smaller axial displacement path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional securing mechanism is used to hold chain links in the receiving pocket, then the chain links are secured, but excessive force is required to insert or remove the chain links

Engineering Contradiction:
Improvesecuring performanceVSAvoidinsertion and removal operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The securing mechanism uses a movable safety pin that can be displaced axially against spring force to transition between locked and unlocked positions. This dynamic mechanism allows easy insertion/removal when the pin is moved, while maintaining secure holding when the pin is in the locked position, resolving the contradiction between securing reliability and ease of operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The safety pin performs both axial displacement and rotational movement to achieve the unlocking function. By adding the rotational dimension to the axial movement, the mechanism achieves effective unlocking with reduced axial travel distance, making insertion and removal easier while maintaining secure holding during normal operation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the safety pin is displaced axially to release the chain link, then the chain link can be removed, but a large axial displacement path is required

Engineering Contradiction:
Improveremoval operationVSAvoidaxial displacement path
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The safety pin is designed to perform rotational movement in addition to axial displacement. This rotational component (more than 50°, preferably 60-120°) allows the pin to exit the slot and release the chain link with a shorter axial travel path, reducing the required displacement to less than once the nominal diameter of the chain link.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

A groove is provided in the safety pin that guides a ball or similar element, which mediates the conversion of axial movement into rotational movement. This intermediary mechanism ensures that the rotational motion occurs automatically during axial displacement, enabling the shortened travel path while maintaining effective unlocking.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Length of moving object

If the safety pin is made to rotate during axial movement, then the axial travel path is shortened, but the mechanism becomes more complex

Engineering Contradiction:
Improveaxial displacement pathVSAvoidlocking mechanism
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The rotational and axial movements of the safety pin are combined into a single integrated action. The groove in the safety pin that guides the ball is formed as part of the pin itself, and the ball is retained in the base body, merging multiple functions into a compact design that does not significantly increase overall mechanism complexity while achieving shortened axial travel.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The safety pin's own geometry (the groove formed in it) serves to guide its rotational movement during axial displacement. The groove and ball combination automatically converts linear motion to rotational motion without requiring external actuators or complex control mechanisms, allowing the mechanism to serve itself.

Inventive Principle:
Principle #25Self-service

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 simplifies the operation of inserting and removing chain links by reducing the required force and axial displacement, enhancing securing performance while preventing accidental actuation, thus improving usability and security.

Implementation Method 1

the safety pin can be reversibly displaced against a spring force

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3640499B1Chain shortening blade
Publication Date: 2022.03.16 THIELE GMBH & CO KG
  • EP3640499B1 patent drawingFigure 1a~1d
  • EP3640499B1 patent drawingFigure 1e~1f
  • EP3640499B1 patent drawingFigure 2a~2d

AI summary

Chain shortening element, in particular chain shortening claw 1 for a link chain 2, comprising an elongated base body 4 with a slotted receiving pocket 8 into which a horizontal chain link 9 can be inserted, such that the horizontal chain link 9 comes to rest with its bend 10 in the receiving pocket 8 and the vertical chain link 13 following it in the longitudinal direction 12 of the chain is arranged in a slot 14 of the receiving pocket 8 which is open on one side and the base body 4 has a coupling point 7 or a second receiving pocket 8 on the side opposite the receiving pocket 8, wherein the vertical chain link 13 is engaged by a locking pin 3 and the locking pin 3 is reversibly displaceable against a spring force, wherein the locking pin 3, when performing an axial movement, also performs a rotational movement and thereby positions a recess 15 formed in the locking pin 3 over the slot 14, such thatthat the stationary chain link 13 can be pulled out of the slot 14 or inserted into the slot 14.