Adjustable Screw-Down Crown for Angular Indexing

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Solution Overview

Problem

Existing screw-down crowns for watches with patterns or non-revolutionary designs face challenges in angular indexing adjustment during assembly, leading to aesthetic issues and limited orientation options, particularly in luxury and high-quality products.

Innovation Solution

An orientable screw-down crown with a subassembly featuring a crown body and a tube, incorporating an indexing relief mechanism and a conical spring for relative rotation, allowing the crown to be indexed to a desired angular orientation after assembly, using a fixed barrel and complementary indexing relief with grooves, and a movable barrel with elastic return for secure mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed screw-down crown is used with a pattern or non-revolutionary design, then the crown provides reliable waterproof sealing, but the crown cannot be adjusted to a desired angular orientation after assembly

Engineering Contradiction:
Improveangular indexing adjustmentVSAvoidcrown structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The crown is divided into two separate parts: a crown body and a tube. The crown body can rotate relative to the tube during assembly to achieve the desired angular orientation, while the tube remains fixed in the housing. This segmentation allows independent positioning of each component, enabling angular indexing without complicating the overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The crown body is preliminarily positioned at the desired angular orientation relative to the tube before final assembly. The indexing relief mechanism allows the crown body to be rotated to the correct angle while still on the tube, ensuring proper orientation is achieved during the assembly process itself rather than requiring post-assembly adjustment.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the crown is screwed tightly in a fixed position during assembly, then the waterproof seal is compressed effectively, but the crown cannot be repositioned angularly after sealing

Engineering Contradiction:
Improvepost-assembly orientation adjustmentVSAvoidwaterproof sealing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The crown assembly transitions from a dynamic state during assembly to a static sealed state. During assembly, the crown body can rotate dynamically on the tube to achieve the desired orientation. Once positioned, the crown is screwed down to compress the seal and lock in place. The indexing relief mechanism enables this transition by allowing rotation only during the assembly process, not after sealing.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The angular orientation is determined preliminarily during assembly before the final sealing action. The crown body is rotated to the desired angle while still accessible, then screwed down to compress the seal. This ensures both the desired orientation and reliable waterproof sealing are achieved without compromising either requirement.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If a simple screw-down crown is used, then the manufacturing is economical, but the crown lacks angular indexing capability for aesthetic positioning

Engineering Contradiction:
Improvemanufacturing costVSAvoidangular indexing
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The crown is segmented into a crown body and a tube that can be manufactured separately using standard, economical processes. The indexing relief features are simple geometric elements (grooves or protrusions) that can be added during manufacturing without requiring complex machinery or expensive materials. This segmentation maintains manufacturing simplicity while enabling angular indexing functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The indexing capability is achieved by changing the geometric parameters of the crown structure - specifically by adding indexing reliefs (grooves or protrusions) at specific angular positions. These are simple dimensional changes that can be incorporated into standard manufacturing processes without significantly increasing cost, yet they provide the desired angular indexing functionality for aesthetic positioning.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If the crown body is made rotatable on the tube during assembly, then angular indexing is enabled, but the risk of losing waterproof sealing increases

Engineering Contradiction:
Improveangular positioningVSAvoidwatertight seal
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The angular positioning is performed preliminarily during assembly while the crown body is still accessible and can rotate on the tube. The indexing relief mechanism allows the crown body to be rotated to the desired angle before final tightening. Once positioned, the crown is screwed down to compress the seal, locking both the angular position and the waterproof seal simultaneously, eliminating the risk of losing sealing after positioning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system transitions from a dynamic state (crown body rotatable on tube) to a static sealed state (crown screwed down compressing seal). During the dynamic phase, angular positioning is achieved through rotation. During the transition to the static phase, the seal is compressed and locked, ensuring waterproofing. The indexing relief mechanism controls this transition, allowing rotation only when needed and preventing it after sealing, thus maintaining reliability.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables simple, economical, and reliable angular indexing of the crown relative to the watch case, maintaining watertight sealing and enhancing the aesthetic appeal of luxury watches by allowing precise orientation adjustments.

Implementation Method 1

a spring which pushes said mobile cannon axially away from said crown body, said spring tending to dismiss said mobile cannon from said crown body

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a seal arranged to cooperate with a support surface which involves said tube and which arranges to compress the seal in the completely screwed position of the subset

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3805874B1Adjustable threaded crown
Publication Date: 2023.12.27 MECO SA
  • EP3805874B1 patent drawingFigure 1~2
  • EP3805874B1 patent drawingFigure 3~4
  • EP3805874B1 patent drawingFigure 5~11

AI summary

A rotating screw-down crown (200) for a watch case (100), a subassembly (20) of which comprises a tube (11) that is axially insertable into a housing (90) in the case, and an operating body (1) having a motif (19) and a relief (15) extending axially and, in the engaged position, cooperating for indexing the motif (19) relative to the case (100) with a complementary relief (55) that is part of a fixed barrel (5) which is pushed away from the body (1) by a spring (12) held between them, and, in the disengaged position by compression of the spring (12) remaining axially distant from the complementary relief (55) and without cooperating with it, the subassembly (20) having an axial stop (3) fixed to the body (1) to axially hold the fixed barrel (5) with a stroke corresponding to the deformation of the spring (12) to allow disengagement, by compression of the body (1), between relief (15) and complementary relief (55).