Watch Strap Horn Blade Interlocking Mechanism

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Solution Overview

Problem

Existing methods for attaching a bracelet to a watch case require skill and tools, often result in visible defects, and provide excessive freedom of movement, compromising the watch's fit on the wrist.

Innovation Solution

A device featuring a horn with a rigid blade that interlocks with a housing in the bracelet strand, along with a bar passing through the horn to secure the bracelet, utilizing a rigid insert and inclined blade for a secure, tool-free attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional piston-based fastening methods are used, then the bracelet can be attached to the watch case, but the operation requires skill and tools, increasing complexity and difficulty of operation

Engineering Contradiction:
Improveease of attachmentVSAvoidcomplexity of fastening mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the complex piston mechanism from the fastening system and replaces it with a simplified blade-housing interlocking system. The bar directly engages with the blade in the housing without requiring pistons, springs, or specialized tools, making the attachment operation straightforward while maintaining secure fastening.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The blade-housing interlocking mechanism is designed to be self-aligning and self-securing. When the bar is inserted through the passage, the blade automatically engages with the housing features, eliminating the need for external tools or skilled manipulation to secure the bracelet.

Inventive Principle:
Principle #25Self-service

2Ease of manufacture

If traditional fastening methods with bars and pistons are used, then the bracelet can be secured, but visible defects and holes may appear at the junction, worsening aesthetic appearance

Engineering Contradiction:
Improveintegration qualityVSAvoidvisible defects
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by designing the blade and housing features to be precisely positioned and shaped within the bar cross-section. The blade is embedded in the housing such that the interface is hidden within the bar's cross-sectional profile, making the junction invisible from external views while maintaining structural integrity.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If traditional fastening methods are used, then the bracelet can be attached, but excessive freedom of movement is allowed, worsening the fit and maintenance on the wrist

Engineering Contradiction:
Improvebracelet movement freedomVSAvoidwatch fit stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs asymmetry in the blade and housing design where the blade has a specific orientation and shape that engages with corresponding asymmetric features in the housing. This asymmetric interlocking provides directional constraints that limit unwanted movement while allowing the natural flexing needed for comfort, achieving optimal fit stability.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3698219B1Fixing device for a bracelet
Publication Date: 2021.10.20 MONTRES BREGUET SA
  • EP3698219B1 patent drawingFigure 1a
  • EP3698219B1 patent drawingFigure 1b~2b

AI summary

The invention relates to a device for attaching a strap to a watch case, the device comprising at least one horn as well as a strap strand, the horn and the strap being held together by means of a bar. According to the invention, the horn comprises a rigid blade arranged to fit together with at least one recess made in the strap strand, said at least one recess having an opening for receiving said blade during the placement of the strap strand so as to form a rigid link once the bar is put in place, towards a second position B in which the insert is locked on the staff.