One-Piece Watch Strap Bar With Elastic Pivot Retraction

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Solution Overview

Problem

Existing methods for attaching a bracelet to a watch, such as spring bars and elastic latching members, are complex and costly to manufacture, and do not allow easy retraction of pivots without tools.

Innovation Solution

A one-piece bar with a body comprising multiple elements connected by recessed portions and peripheral frames of a substantially closed 'M' shape, providing longitudinal elasticity and allowing easy deformation for attachment and detachment, while being made from cost-effective materials like plastic or rubber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a spring bar with multiple components is used, then the attachment mechanism is functional, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidnumber of components
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines multiple components (bar body, spring element, and latching mechanism) into a single integrated spring bar. The bar body includes an elastic portion and a latching portion formed as one piece, eliminating the need for separate assembly of multiple parts and reducing manufacturing complexity while maintaining functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring bar is segmented into functional portions (elastic portion and latching portion) within a single integrated structure. This allows the bar to be manufactured as one piece while still providing the functional separation needed for elasticity and latching operations.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If a traditional spring bar is used, then the attachment is secure, but the pivot retraction requires tools and multiple steps

Engineering Contradiction:
Improvepivot retraction easeVSAvoidattachment/detachment time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The latching portion is designed to be manually operable without tools. The user can directly manipulate the latching portion to retract the pivot from the housing, enabling tool-free attachment and detachment operations.

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 offers a simplified, cost-effective, and robust attachment mechanism with improved flexibility and resistance to breakage, allowing easy retraction and prolonged lifespan without material aging.

Implementation Method 1

The elastic portion is configured to deform elastically in a longitudinal direction in which the bar extends

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3647882B1One-piece bar for attaching a strap to a watch
Publication Date: 2025.01.01 THE SWATCH GRP RES & DEVELONMENT LTD
  • EP3647882B1 patent drawingFigure 1

AI summary

The invention relates to a one-piece bar for attaching a bracelet to a watch, the bar extending along a longitudinal direction and comprising two pivots and a body connecting the two pivots, each pivot being intended to fit into a corresponding housing of a respective lug of a watch case, the body comprising a plurality of elements connected to each other, each element having a hollowed-out portion, so as to give longitudinal elasticity to the bar to allow its elastic deformation along the longitudinal direction.