Watch Strap Snap-Fit System with Spring-Loaded Blade and Ramp Guide

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Solution Overview

Problem

Existing watch strap fastening systems are complex, difficult to use, and prone to damaging the watch case when changing straps, with many requiring specialized tools and causing scratches.

Innovation Solution

A flexible blade actuation system with a push button mechanism that allows easy clipping and unclipping of the strap, using a ramp for guided extraction and elastic means to absorb stress, ensuring the system is simple, safe, and suitable for thin bracelets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If spring-loaded spring bars are used to attach the strap, then the attachment mechanism is simple, but the pins scratch the inside of the lugs during insertion

Engineering Contradiction:
Improveattachment mechanismVSAvoidscratches on lugs
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by providing a ramp surface on the insert that guides the bar into the cage before the locking mechanism engages. This ramp ensures proper alignment and positioning of the bar within the cage prior to locking, preventing misalignment that would cause scratching during insertion.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary element - the ramp surface - that mediates between the bar and the cage. This ramp acts as a guiding interface that controls the insertion motion, ensuring the bar enters the cage smoothly and correctly positioned, thereby eliminating direct harmful contact that would cause scratches.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If pins are pushed outwards by a spring for automatic attachment, then simplicity is achieved, but the pins cannot be independently positioned and may become blocked

Engineering Contradiction:
Improveautomatic attachmentVSAvoidindependent pin positioning
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent divides the attachment function into separate elements: the bar with its two ends can be independently inserted into the cage, and the locking mechanism operates separately from the insertion process. This segmentation allows each pin (bar end) to be positioned independently while maintaining automatic attachment through the spring-loaded locking system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamics by making the locking mechanism movable rather than fixed. The locking element can dynamically adjust its position along the bar, allowing independent positioning of each bar end while maintaining the spring-loaded automatic locking function. This dynamic capability prevents blocking by accommodating variations in insertion timing and positioning.

Inventive Principle:
Principle #15Dynamics

3Extent of automation

If a complex tongue structure with folding zones is used for automatic attachment, then automatic attachment is achieved, but the construction becomes complicated and requires precise adjustments

Engineering Contradiction:
Improveautomatic attachmentVSAvoidtongue construction
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent extracts the essential automatic attachment function from the complex folded tongue structure and implements it through a simpler mechanism: a bar inserted into a cage with a locking system. This extraction removes the unnecessary folding zones and complex geometry while retaining the automatic attachment capability through spring-loaded locking.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies self-service by designing a mechanism where the spring automatically performs the locking action without requiring complex folded structures or precise manual adjustments. The spring-loaded system self-activates upon insertion, and the ramp surface guides the bar into correct positioning automatically, eliminating the need for complex pre-adjusted folding zones.

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

Enables quick and easy strap exchange without damaging the watch case, maintaining safety and stability while being compact and easy to implement, suitable for various materials and activities.

Implementation Method 1

elastic means, for example a spring, capable of absorbing stress and of returning the flexible blade into its initial position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3470935B1Snap-fitting system, for example for attaching a band to a watch
Publication Date: 2022.08.17 D HEURE EN HEURE SARL
  • EP3470935B1 patent drawingFigure 1~3
  • EP3470935B1 patent drawingFigure 4~5
  • EP3470935B1 patent drawingFigure 6~7

AI summary

The system for attaching a variable element (1), such as a bracelet, to a fixed object, such as a watch case, includes at least means for attaching said element to the fixed object. The attachment means include a spring-loaded blade (31) and a button (32) for actuating the blade, said blade (31) allowing the attachment system to be closed.