Bracelet Clasp Spring Assembly Segmentation for Rigidity

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Solution Overview

Problem

Existing folding clasps face challenges in maintaining constructive rigidity while providing the necessary elasticity for proper leaflet attachment and release, particularly when forces are exerted on the spars or longitudinal members.

Innovation Solution

The implementation of a base element and leaflet comprising at least two spring blades as the elastic device, which allows for simultaneous pressure exertion to unlock the leaflets or leaflet from the base element, enhancing rigidity and elasticity through the use of thin spring blades and solid spacers to prevent warping and friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single longitudinal member is used in the base element or leaflet, then the device complexity is reduced, but the constructive rigidity is insufficient and warping occurs

Engineering Contradiction:
Improvestructure complexityVSAvoidconstructive rigidity
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent applies segmentation by dividing each longitudinal member into multiple spring blades (at least two) that are stacked and articulated together. This segmentation allows each blade to contribute to the overall rigidity while maintaining the elasticity needed for the folding mechanism, thereby resolving the contradiction between structural simplicity and constructive rigidity.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If thin spring blades are used to provide elasticity, then the ease of manufacture is improved, but the constructive rigidity deteriorates due to warping

Engineering Contradiction:
Improvemanufacturing easeVSAvoidwarping resistance
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent segments the longitudinal members into multiple thin spring blades that are stacked together. This segmentation allows each individual blade to remain thin and easy to manufacture while the stacked assembly collectively provides the necessary rigidity and resistance to warping, thus resolving the contradiction between ease of manufacture and warping resistance.

Inventive Principle:
Principle #1Segmentation

3Strength

If multiple spring blades are stacked to double the stiffness, then the strength is improved, but the force required to unhook the leaflets increases

Engineering Contradiction:
Improvespring stiffnessVSAvoidunhooking force
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The patent employs dynamics by designing the spring blade assembly to be articulated and movable rather than rigidly fixed. The multiple spring blades can deflect and move during the unhooking process, allowing the increased stiffness to be dynamically managed. This enables the system to provide strong holding force when closed while still allowing controlled release when force is applied, resolving the contradiction between strength and unhooking force.

Inventive Principle:
Principle #15Dynamics

4Reliability

If solid spacers are added between spring blades to prevent friction, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvefriction preventionVSAvoidcomponent quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces solid spacers as intermediary elements between the spring blades. These spacers act as mediators that prevent direct contact and friction between the blades while maintaining the stacked configuration. This intermediary approach resolves the contradiction by providing reliable friction prevention without requiring complex mechanical structures, as the spacers are simple geometric elements integrated into the blade assembly.

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

This configuration doubles the stiffness of the spring assembly, maintaining deflection while requiring twice the force to unhook the leaflets, ensuring secure attachment and easy release, and avoids issues like warping and friction, with the option to fill spaces with soft materials for added comfort.

Implementation Method 1

an elastic device composed of at least two spring blades which make up each of the spars or longerons

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2870893B1Bracelet clasp
Publication Date: 2016.06.08 THE SWATCH GROUP MANAGEMENT SERVICES AG
  • EP2870893B1 patent drawingFigure 1~2
  • EP2870893B1 patent drawingFigure 3~5
  • EP2870893B1 patent drawingFigure 6~7

AI summary

The bracelet clasp includes a rectangular base element wherein each of the long sides is formed of side bars each formed of at least two leaf springs forming an elastic device allowing first and second folding parts to be locked onto said base element and disengaged therefrom when a pressure is exerted simultaneously on said side bars.