Watch Strap Bar with Retractable Pivots for Tool-Free Interchangeability

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Solution Overview

Problem

Existing watch bracelet attachment devices require significant structural modifications and protruding elements that can be inconvenient for wearers, leading to increased manufacturing costs and potential injury risks.

Innovation Solution

A device comprising a bar secured to the watch case with a pivot and notch system, along with a removable cover and ball pawls, allows for easy assembly and disassembly of the bracelet without major structural changes, using a bar with flanges and grooves to securely hold the insert in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional fixing devices with radial fingers and axial slots are used, then the bracelet can be separated from the case without using a tool, but the actuating member protrudes and can catch on or injure the wearer

Engineering Contradiction:
Improvetool-free bracelet separationVSAvoidprotruding actuating member causing injury risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the actuating function from a protruding radial finger and relocates it to a button element that is flush with the bracelet end surface. The button can be pressed laterally to actuate the release mechanism without protruding beyond the bracelet's outer contour, thereby eliminating the injury risk while maintaining tool-free operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a radial finger that protrudes outward to push the piston back, the invention uses a button that is pressed laterally (perpendicular to the traditional radial direction). This inverted actuation direction allows the release mechanism to be triggered without any protruding elements, solving the safety hazard while preserving ease of operation.

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

2Adaptability or versatility

If interchangeable bracelet devices with actuating members are used, then the bracelet can be removed and replaced, but significant structural modifications are required at the bar level, leading to increased manufacturing costs

Engineering Contradiction:
Improveinterchangeable bracelet capabilityVSAvoidmanufacturing cost due to structural modifications
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The invention segments the interchangeable bracelet mechanism into distinct functional components: a bar with piston and tube assembly, an insert with housing, and a button actuator. This segmentation allows each component to be manufactured separately using standard processes, avoiding the need for major structural modifications to the bar itself, thereby reducing manufacturing costs while maintaining interchangeability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an insert as an intermediary component that mediates between the bar and the button actuator. The insert contains the housing and provides the interface for the button to actuate the piston, allowing the bar to remain structurally simple and easy to manufacture while still enabling interchangeable bracelet functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If a bar with piston and elastic member is used, then secure attachment to the watch case is achieved, but a tool is required to push the pistons back against the elastic member stress for separation

Engineering Contradiction:
Improveattachment securityVSAvoidtool requirement for bracelet separation
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The invention makes the bracelet attachment system self-servicing by incorporating a button actuator that the wearer can operate directly. When the button is pressed, it automatically pushes the piston back against the elastic member's stress, triggering the release mechanism without requiring any external tools. This maintains the secure attachment provided by the elastic member while enabling tool-free separation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3756501B1Fixing device for a bracelet
Publication Date: 2023.06.21 MONTRES BREGUET SA
  • EP3756501B1 patent drawingFigure 1~2
  • EP3756501B1 patent drawingFigure 3a~3c
  • EP3756501B1 patent drawingFigure 4~6

AI summary

The invention relates to a device for attaching a watch strap to a watch case. The device comprises, on the one hand, a bar attached to the watch case by means of a lug, and on the other hand, an insert attached to the end of a strap. The bar and the insert are complementary and cooperate by interlocking, forming removable assembly means to make the strap interchangeable. According to the invention, the bar is formed by a cylindrical hollow body equipped with two retractable pivots and having at least one housing. This housing is arranged to cooperate by interlocking with an insert. The bar includes means for retaining the insert. The bar is arranged to pivot from a first position in which the insert can be positioned on the bar, to a second position in which the insert is locked onto the bar by means of locking means cooperating with said retaining means.