Watch Strap Interchangeable Attachment System

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Solution Overview

Problem

Existing watch buckle systems lack efficient and tool-free mechanisms for easily swapping straps without damaging the buckle, particularly for valuable items where the buckle should remain intact.

Innovation Solution

A fastening system with a first and second fastening element, a locking mechanism, and a return element that allows for tool-free attachment and detachment of a watch strand, preventing involuntary detachment and enabling easy swapping of straps while maintaining the buckle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a pin bar system is used to attach the strand to the buckle, then the strand can be detached, but the buckle is damaged and cannot be reused

Engineering Contradiction:
Improvestrand detachmentVSAvoidbuckle integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The fastening system is divided into separate components: a first fastening element attached to the strand, a second fastening element attached to the buckle, and a locking mechanism. This segmentation allows the strand to be detached and reattached multiple times without damaging the buckle, as the damage-prone pin bar is replaced with a reusable locking mechanism comprising a locking element and return element.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention enables the buckle to be recovered and reused after strand detachment. Instead of the traditional pin bar system that damages the buckle upon removal, the locking mechanism allows the strand to be detached and reattached indefinitely without compromising the buckle's integrity, effectively recovering the buckle for continuous use.

Inventive Principle:
Principle #34Discarding and recovering

2Adaptability or versatility

If the buckle is modified to allow strand removal, then the strand can be swapped, but the buckle's value is reduced through modifications

Engineering Contradiction:
Improvestrand interchangeabilityVSAvoidbuckle value preservation
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The fastening system separates the interchangeability function into distinct components: the first fastening element on the strand and the second fastening element on the buckle, connected by a locking mechanism. This allows strand interchangeability without modifying the buckle's essential structure, preserving its value while enabling versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking mechanism serves multiple functions: it secures the strand to the buckle, enables tool-free detachment, prevents involuntary detachment through the return element's elastic biasing, and allows repeated use. This multi-functionality achieves strand interchangeability without compromising the buckle's value.

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

3Reliability

If a traditional fastening system is used, then the buckle remains secure, but tool-free strand swapping is not possible

Engineering Contradiction:
Improvebuckle securityVSAvoidtool-free strand swapping
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism is designed to operate without tools through self-service principles. The locking element automatically engages with the return element through elastic biasing, and the user can detach the strand by simply pressing the release element, which triggers the locking element to disengage. This provides tool-free strand swapping while maintaining secure attachment during wear.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The locking mechanism transitions between locked and unlocked states dynamically. The locking element is biased by the return element to engage automatically when the strand is attached, and can be easily disengaged when needed. This dynamic behavior provides both security during wear and ease of operation for swapping.

Inventive Principle:
Principle #15Dynamics

4Reliability

If the locking mechanism uses elastic biasing, then involuntary detachment is prevented, but the mechanism complexity increases

Engineering Contradiction:
Improveprevention of involuntary detachmentVSAvoidlocking mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The elastic biasing function is extracted into a separate return element that independently provides the necessary force to keep the locking element engaged. This separation simplifies the overall design by dedicating specific components to specific functions: the locking element for engagement, the return element for biasing, and the release element for actuation, reducing overall mechanism complexity while maintaining reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The return element acts as an intermediary between the locking element and the strand attachment. It provides elastic biasing to ensure the locking element remains engaged during normal wear, preventing involuntary detachment, while allowing easy disengagement when the release element is actuated. This intermediary component adds reliability without significantly increasing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables secure, tool-free, and damage-free swapping of watch straps, providing flexibility in choosing bracelet designs without altering the buckle or watch case.

Implementation Method 1

a return element. The locking mechanism is configured such that the first locking member moves relative to the second locking member between a locked position and an unlocked position. In the locked position, the first locking member is engaged with the second locking member, the biasing member exerting a pressing force between the two locking members

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

In the unlocked position, an unlocking force opposite the pressing force is exerted on the biasing member, disengaging the second fastening member from the transverse housing

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4151116B1Attachment system for interchangeable strand
Publication Date: 2025.06.25 D HEURE EN HEURE SARL
  • EP4151116B1 patent drawingFigure 1a~1b
  • EP4151116B1 patent drawingFigure 1c~1e
  • EP4151116B1 patent drawingFigure 1f~2a

AI summary

A fastening system (1) intended to removably attach a strand (60) to a component (50); the fastening system (1) comprising: a first fastening element (10) intended to be attached to the strand (60) and having a transverse housing (11); a second fastening element (20) configured to be directly or indirectly attached to the component (50) and comprising a connecting portion (210) arranged to cooperate with the transverse housing (11); and a locking mechanism comprising a first locking element (12) provided on the fastening element (10) and a second locking element (212) provided on the second fastening element (20).The first locking element (12) moves relative to the second locking element (212) between a locked position in which the first locking element (12) is engaged with the second locking element (212), and an unlocked position, in which the first and second locking elements (12, 212) are not engaged.