Indexed Screw-Down Watch Crown for Precise Motif Orientation

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Solution Overview

Problem

Existing screw-down crowns on watches do not allow for precise angular indexing and orientation adjustment, especially when featuring inscriptions or motifs, detracting from the aesthetic appeal of luxury and high-quality products.

Innovation Solution

A screw-on orientable crown with integral angular indexing means and a subassembly that includes a fixed barrel and a tube, allowing for irreversible fixation through laser welding or gluing, enabling precise angular adjustment and sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If current mounting methods are used for screw-down crowns, then the assembly process is simple and well-known, but the crown cannot be positioned in a specific orientation relative to the case, which detracts from aesthetic appearance

Engineering Contradiction:
Improveangular positioning precisionVSAvoidmounting mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mounting mechanism is divided into separate components: a first tube with external threading, a second tube with internal threading, and a locking member. This segmentation allows each component to perform its specific function while maintaining overall simplicity of the assembly process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Indexing means are pre-formed on the first and second tubes before assembly. These indexing features (such as grooves, ridges, or notches) are created during manufacturing, so that when the tubes are screwed together, the angular orientation is automatically determined without requiring additional adjustment steps.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If a screw-down crown with inscription or motif is used, then aesthetic appeal is improved, but the ability to adjust angular indexing after mounting is lost

Engineering Contradiction:
Improveangular adjustment capabilityVSAvoidmounting stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The mounting system transitions from a static fixed position to a dynamic adjustable position. The locking member can be disengaged from the indexing means, allowing the crown to be removed and re-mounted at different angular orientations. Once the desired orientation is achieved, the locking member engages to provide a stable fixed position.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking member acts as an intermediary between the first and second tubes. It controls the engagement and disengagement of the indexing means, enabling both temporary adjustability and final stable fixation. This intermediary component allows the system to exhibit both dynamic and static characteristics as needed.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the crown is made irreversibly fixed through welding or gluing, then mounting stability is improved, but adaptability for orientation adjustment is reduced

Engineering Contradiction:
Improvecrown fixation stabilityVSAvoidorientation repositioning capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system provides its own adjustment and fixation mechanisms without requiring external welding or gluing processes. The threading between tubes provides self-holding capability, while the locking member with indexing means enables self-adjustment to various orientations. This eliminates the need for irreversible external fixation methods.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3805872B1Adjustable threaded crown
Publication Date: 2025.11.26 MECO SA
  • EP3805872B1 patent drawingFigure 1~2
  • EP3805872B1 patent drawingFigure 3~4
  • EP3805872B1 patent drawingFigure 5~6

AI summary

Rotatable screw-on crown (200) for watch case (100), comprising axially movable sub-assemblies (20) including an operating body (1) having a motif (19) and carrying a fixed axial barrel (2) having a first thread (21), and a tube (7) axially insertable into a housing (90) of the case and including angular indexing means (75) which are arranged to cooperate with complementary angular indexing means (45) which include an insert (4) mounted on this tube (7) to determine the angular orientation, with respect to an axial direction (D), of the crown body (1) with respect to the tube (7), which insert (4) includes a first tapping (41) arranged to cooperate with the first thread (21) of the fixed barrel (2) for screwing the crown body (1) into the tube (7).