Removable-Support Watch Fixing Device for Tool-Free Strap Changes

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Solution Overview

Problem

Existing watch attachment mechanisms are difficult to detach without tools, aesthetically unappealing, and can lead to the watch case falling during impacts, while requiring additional components for each strap change.

Innovation Solution

A flange-based fixing device with inner ribs and cutouts allows easy attachment and detachment of the watch case to a bracelet without tools, providing secure support and maintaining the watch's appearance by hiding the mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ring is fixed to the base-cap by driving, then the ring remains fixed on the case to hold the bracelet, but it becomes difficult for users to remove the ring to separate the bracelet from the watch case

Engineering Contradiction:
Improvefixing reliabilityVSAvoidease of removal
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The fixing device transitions from a static driven connection to a dynamic snap-fit mechanism. The resilient element allows the fixing device to be inserted easily and locked automatically, while also enabling simple removal by applying outward force to overcome the elastic retention force.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The fixing device is separated into distinct functional elements: a resilient element for automatic locking, a locking element for engagement, and a release mechanism. This segmentation allows independent optimization of each function - secure locking during wear and easy release when needed.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If a ring or band is used to attach the bracelet to the watch case, then the bracelet can be easily changed, but the ring appears visibly around the watch case which detracts from the aesthetic appearance

Engineering Contradiction:
Improveease of bracelet changeVSAvoidaesthetic appearance
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The visible ring or band is extracted from the design and replaced by a concealed fixing device. The fixing mechanism is integrated into the case structure with components that remain hidden during normal wear, eliminating the aesthetic drawback while preserving the ease of bracelet replacement functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fixing device components are nested within the case structure. The resilient element, locking element, and other components are positioned within recesses and openings of the case, allowing them to function while remaining concealed from external view.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Adaptability or versatility

If the ring is mounted around the case on the dial side, then the bracelet can be attached, but the ring appears visibly around the dial of the watch which detracts from the aesthetic appearance

Engineering Contradiction:
Improvebracelet attachment capabilityVSAvoiddial appearance
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

Instead of mounting the fixing mechanism on the visible dial side, the invention inverts the approach by placing all fixing components on the concealed case back or within internal recesses. The bracelet attaches to external lugs while the fixing mechanism remains hidden, reversing the traditional visible-ring approach.

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

4Reliability

If the fixing device uses a resilient element with locking ribs, then it provides secure support and prevents the watch case from falling during impacts, but the structure becomes more complex

Engineering Contradiction:
Improvesupport and protection capabilityVSAvoidfixing device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple functions are merged into single components. The resilient element simultaneously provides mounting support, shock absorption, and locking engagement. The locking element combines the locking rib and release mechanism in one integrated piece, reducing overall structural complexity while maintaining protective capabilities.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3088970B1Watch intended for being mounted on a removable support
Publication Date: 2025.09.10 ETA SA MFG HORLOGERE SUISSE
  • EP3088970B1 patent drawingFigure 1
  • EP3088970B1 patent drawingFigure 2
  • EP3088970B1 patent drawingFigure 3~4

AI summary

The invention relates to a watch (1) intended to be mounted on a support (2) in a removable manner, comprising a watch case (4) and a removable, independent fixing device (10) arranged to hold the watch case (4) in an opening (3) provided on the support (2), the watch case (4) comprising an upper part (4a), dial side, and a lower part (4b) comprising a base (5), said lower part (4b) being arranged to fit into the opening (3) of the support (2) and being smaller than the dimensions of the upper part (4a) to form a flat peripheral shoulder (8). According to the invention, the fastening device (10) comprises a flange (12) having a central opening (14) arranged to receive the lower part (4b) of the watch case (4) and an inner rim (16) delimiting said central opening (14), said inner rim (16) being arranged to fit into the opening (3) of the support (2).The inner rim (16) has on its inner wall locking means for the fastening device (10) on the lower part (4b) of the watch case (4), arranged to allow locking of the fastening device (10) on the watch case (4) so ​​as to be able to hold the support (2) between the flange (12) and the flat shoulder (8) of the watch case (4) and to allow unlocking of the fastening device (10) of the watch case (4) by application on the flange (12) of a force (F) substantially perpendicular to the flange (12) and directed outwards so as to be able to release the support (2).