Expandable Watch Strap With Loop Stop Surface

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Solution Overview

Problem

Traditional watch straps face limitations in adjustment range, ease of use, and durability, particularly failing to accommodate diverse user morphologies and handling conditions such as wearing gloves or withstanding strong accelerations.

Innovation Solution

A watch strap design featuring an extensible strand with a loop that can surround a watch case, utilizing stop surfaces for secure attachment and adjustable tensile force, allowing for easy donning and removal without a traditional clasp, and incorporating elastic or rigid elements for flexibility and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional clasps (pin buckles or folding clasp mechanisms) are used, then secure attachment is achieved, but ease of operation deteriorates due to delicate handling requirements and inability to use with gloves

Engineering Contradiction:
Improvesecure attachmentVSAvoidhandling ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent removes the traditional clasp mechanism entirely from the watch bracelet system. Instead of using pin buckles or folding clasps, the invention employs a simple loop that passes through the watch case and secures with a stop surface, eliminating complex clasping mechanisms that require delicate handling.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than using a clasp that closes around the watch case, the invention inverts the approach by using a loop that passes through the watch case from the back, with the stop surface preventing removal. This reversal simplifies the operation to a single pulling motion that works even with gloves on.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If traditional clasps are used, then secure attachment is achieved, but device complexity increases due to multiple components and assembly steps

Engineering Contradiction:
Improvesecure attachmentVSAvoidclasp mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the entire traditional clasp mechanism (pin buckles, folding clasps, multiple links) from the watch bracelet system. The replacement is a simple loop with a stop surface that integrates directly with the watch case, dramatically reducing component count and assembly complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the functions of the clasp, anchor point, and adjustment mechanism into a single integrated loop structure that works with the watch case. The stop surface on the loop cooperates directly with the watch case geometry, eliminating the need for separate clasp components and simplifying the overall system.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If bracelets are made entirely of elastic material, then ease of operation improves, but reliability deteriorates under strong accelerations

Engineering Contradiction:
ImproveflexibilityVSAvoidhold security
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent employs a composite construction where the bracelet combines elastic material segments with rigid structural elements. The elastic portions provide flexibility and ease of operation, while the rigid loop with stop surface and watch case integration provide reliable anchoring that resists strong accelerations and maintains secure hold.

Inventive Principle:
Principle #40Composite materials

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 design provides a wide adjustment range, ease of use, and enhanced durability, ensuring a secure fit during wear, even under strong accelerations, and is suitable for both professional and sports use, while being glove-friendly and cost-effective.

Implementation Method 1

at least one extensible strand (4)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3058840B1Expandable wristwatch
Publication Date: 2018.04.18 SWATCH SA
  • EP3058840B1 patent drawingFigure 1~2
  • EP3058840B1 patent drawingFigure 3~4
  • EP3058840B1 patent drawingFigure 5~7

AI summary

Bracelet (3) comprising an extendable strap (4). This bracelet (3) comprises a buckle (5) arranged to encircle a case (2) or a projecting element of said bracelet (3), formed by said extendable strap (4) or by an added buckle (59), and said buckle (5) comprising a stop surface (50) arranged to cooperate, in an engaged position, with either a first complementary stop surface (20) of said case (2), or with a second complementary stop surface (30) of said projecting element of said bracelet (3). Watch (1) comprising, attached to a case (2), such a bracelet (3), of which said buckle (5) is arranged to cooperate with said case (2).