Watch Strap Attachment Device with Rotating Bar and Gutter Mechanism

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Solution Overview

Problem

Conventional attachment devices for timepieces and leather goods require tools for assembly and disassembly, making it impractical for users to change bracelets or clasps easily.

Innovation Solution

A fastening device with two elements, one featuring a bar and the other with opposing longitudinal openings, allowing rotation from an unhooked to a hooked position, enabling tool-free assembly and disassembly by articulating on the bar, with gutters having a slight size advantage and cylindrical housings for smooth rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional bars or pins are used for attachment, then the structure is simple and reliable, but tool assembly and disassembly is required making it impractical for users

Engineering Contradiction:
ImproveEase of assembly and disassemblyVSAvoidDevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The attachment device is divided into two separate elements: a first element with a bar and a second element with two gutters. This segmentation allows the bar to be inserted into the gutters independently, enabling tool-free assembly while maintaining structural reliability. The segmented design resolves the contradiction by making the attachment mechanism user-friendly without requiring complex tool-based operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment mechanism transitions from a static fixed connection to a dynamic rotational movement. The bar rotates within the gutters from an unhooked position to a hooked position, allowing easy attachment and detachment. This dynamic movement enables users to quickly assemble and disassemble the attachment without tools, improving ease of operation while keeping the device structure relatively simple.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the longitudinal opening of gutters is made slightly smaller than the bar, then the fit is secure and reliable, but insertion requires slight force

Engineering Contradiction:
ImproveAttachment reliabilityVSAvoidEase of insertion
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The dimensional parameters of the gutter opening and bar are carefully optimized. The longitudinal opening is made slightly smaller than the bar diameter, creating a friction fit that ensures reliable attachment. This parameter optimization resolves the contradiction by achieving secure attachment without requiring excessive insertion force, as the slight interference fit provides reliability while the rotational movement facilitates easy insertion.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3318156B1Attachment device
Publication Date: 2019.07.10 MONTRES BREGUET SA
  • EP3318156B1 patent drawingFigure 1
  • EP3318156B1 patent drawingFigure 2a~2d

AI summary

The invention relates to a device for attaching two elements of a watch strap to allow the two elements to be attached or detached, the first element comprising at least one bar at one of its ends. According to the invention, the second element comprises two grooves, each having a longitudinal opening opposite each other, one of the two elements being able to move from a detached position in which one of the elements is oriented at a predetermined angle relative to the other element, to a detached position in which the two elements are coplanar after a rotation of one of the two elements relative to the other by a predetermined angle such that each groove is hinged on the bar and holds the two elements attached to each other.