Adjustable Bracelet Pin Track Mechanism for Tool-Free Sizing

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Solution Overview

Problem

Conventional bracelets often require specialized tools or professional assistance to adjust, leading to inconsistent fit due to seasonal changes in wrist size and lack of fine-tuning adjustments, making them uncomfortable and impractical for various wear scenarios.

Innovation Solution

An adjustable bracelet design featuring a clasp with a track system and a pin mechanism that allows for precise length adjustments without tools, using first and second opening sections of varying heights to restrict or allow pin movement, along with spring-loaded buttons for frictional retention, enabling users to easily adjust the bracelet length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If links are removed to adjust bracelet length, then the bracelet can be shortened, but special tools or jeweller assistance are required

Engineering Contradiction:
Improveease of adjustmentVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The bracelet is divided into modular links that can be independently adjusted. The clasp mechanism is segmented into movable components (link, pin, opening sections) that allow incremental length adjustments without requiring removal of entire link sections, enabling user-friendly adjustment while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The clasp mechanism incorporates dynamic elements including a rotatable link with a pin that can move between different opening sections. The spring-loaded buttons provide dynamic retention that holds the link in position during adjustment but releases when force is applied, enabling easy user operation without complex tools.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If one link is removed, then the bracelet length is reduced, but the bracelet becomes too loose; if two links are removed, then the bracelet is shorter, but it becomes too tight

Engineering Contradiction:
Improvelength adjustment precisionVSAvoidfit adaptability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

Instead of requiring removal of entire links (excessive action), the mechanism allows partial adjustment by moving the pin between multiple opening sections within the clasp. This enables fine-grained length adjustment in incremental steps, providing precise fit control without the all-or-nothing constraint of traditional link removal.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The mechanism changes the adjustment parameter from discrete link count (1 link = fixed length reduction) to continuous pin position along the track (multiple opening sections = variable length adjustment). This allows the bracelet length to be precisely tuned to match wrist size variations across different seasons and wear scenarios.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the bracelet fit is adjusted for summer wear, then it fits tightly in summer, but it becomes too loose in winter

Engineering Contradiction:
Improveseasonal fit adaptabilityVSAvoidre-adjustment ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The bracelet adjustment mechanism is designed for user self-service operation. The spring-loaded buttons and movable link allow the wearer to easily adjust the bracelet length themselves without requiring professional assistance, enabling quick adaptation to seasonal fit changes through simple manual manipulation.

Inventive Principle:
Principle #25Self-service

4Ease of operation

If a traditional clasp is used, then the structure is simple, but the link cannot be rotated or adjusted

Engineering Contradiction:
Improvelink rotatabilityVSAvoidclasp mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The link with the pin is nested within the clasp mechanism, specifically within the track formed by opening sections. The pin fits within the openings, and the entire link assembly rotates within the clasp structure. This nested arrangement allows rotational adjustment functionality while containing all components within a compact footprint, minimizing overall mechanism complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 comfortable, secure, and stylish fit adjustments without requiring special tools or professional assistance, accommodating seasonal changes and various wrist sizes, while maintaining the same bracelet structure, thus increasing user enjoyment and resale value.

Implementation Method 1

The buttons are adapted to allow frictional retention of the link in a cover of the clasp when the link is approximately parallel to the track

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3097812B1Adjustable bracelet
Publication Date: 2017.11.01 FOSSIL GROUP INC
  • EP3097812B1 patent drawingFigure 1A~1B
  • EP3097812B1 patent drawingFigure 1C~2A
  • EP3097812B1 patent drawingFigure 2B~2C

AI summary

A bracelet may be adjustable. The bracelet may be a portion of a watch and/or jewelry. The bracelet may include a clasp with a track that includes a plurality of first openings and second openings. A first end of the bracelet may include a link with a pin. The pin may be disposed in the track, and the length of the bracelet may be adjusted by moving the pin along a length of the track. The pin may have a length and a cross-sectional shape perpendicular to the length. The cross-sectional shape may allow the pin to travel along the length of the track when the link is disposed at an angle relative to the length of the track and may restrict the pin from travelling along the length of the track when the link is approximately parallel to the length of the track.