Retractable Leash Coupling Mechanism for Tangling Prevention

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Solution Overview

Problem

Existing dog leashes, such as flexi leashes and retractable leashes, have limitations that make them impractical for various situations, particularly during training or in dense environments, and often require multiple leashes to be carried for different scenarios.

Innovation Solution

A leash device with a retractable mechanism that allows the leash to be decoupled and reconnected from the retractor mechanism, enabling it to function as both a flexi leash and a retractable leash, with features like a translational coupling mechanism, elastic elements, and locking mechanisms to manage leash length and prevent tangling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a long retractable leash is used, then the dog can be controlled at a distance and training is enabled, but the leash easily gets tangled in undergrowth or between legs

Engineering Contradiction:
Improveleash lengthVSAvoidtangling
Core Design Contradiction:
Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent implements a dynamic leash system where the coupling mechanism can transition between coupled and uncoupled states. The leash length is dynamically adjustable - when coupled, the retractor mechanism automatically manages leash length and prevents tangling; when uncoupled, the full leash length is available for training. This dynamic state change resolves the contradiction between needing long leash length and avoiding tangling.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the leash is kept short to prevent tangling, then control is maintained, but the dog cannot be trained with extended range

Engineering Contradiction:
Improveleash function adaptabilityVSAvoidmanual adjustment frequency
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent creates a universal leash device that combines both flexi leash and retractable leash functions in a single device. The coupling mechanism enables the leash to operate in two modes: coupled mode for automatic retraction and short leash functionality, and uncoupled mode for extended range training. This multi-functionality eliminates the need for owners to carry multiple leashes and manually switch between them, resolving the contradiction between adaptability and ease of operation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple leashes are carried for different situations, then all training and walking needs are covered, but the device complexity and portability are reduced

Engineering Contradiction:
Improveleash functionalityVSAvoidnumber of devices to carry
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the functionality of two separate leashes (flexi leash and retractable leash) into a single integrated device. The coupling mechanism allows the same leash to perform both functions by simply changing its coupling state. This consolidation reduces the number of devices owners need to carry and manage, while maintaining full functionality for both casual walking and training scenarios, thus resolving the contradiction between adaptability and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 device provides a versatile solution that prevents tangling and allows seamless transition between leash functions, enhancing usability and safety by adapting to different environments and situations without the need for multiple leashes.

Implementation Method 1

the coupling mechanism has an elastic element, in particular a spring, which acts with a permanent force on the coupling mechanism

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

Reeling is usually achieved by a reeling mechanism consisting of a drum and a torsion spring. The torsion spring applies a torque to reel the leash onto the drum

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP4387438B1Leash device with reel mechanism
Publication Date: 2025.10.01 NOGEL CLAUDIA
  • EP4387438B1 patent drawingFigure 1
  • EP4387438B1 patent drawingFigure 2~3
  • EP4387438B1 patent drawingFigure 4~5

AI summary

: The invention relates to a leash device (10) for animals, in particular for dogs, comprising: a housing (30) which is designed to be held by a person; a retraction mechanism (40) which is arranged inside the housing (30); a leash (20) which is designed to be connected by one end to an animal and by the other end, via a coupling mechanism (50), to the retraction mechanism (40) of the leash device; wherein the retraction mechanism (40) is designed to retract the leash (20) into the housing (30) from an at least partially extended state; and wherein the coupling mechanism (50) is designed to uncouple the leash (20) from the retraction mechanism (40) when the leash is completely extended.