Watch Case Crown Angular Positioning Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing watch case designs fail to precisely and reliably orient a distinctive sign on the control crown relative to the watch case's longitudinal axis, often requiring complex and difficult-to-implement solutions that lack precision or are aesthetically unsatisfactory.
Innovation Solution
A watch case design featuring a screw-down crown with an internal part and an external part having micro toothing or splines for angular indexing, combined with a clamping ring and coil spring mechanism, allowing for precise and reproducible angular positioning of the distinctive sign.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If frustoconical surfaces are used to clamp the outer part and inner part of the crown, then angular orientation can be achieved, but the conicity must be almost identical and relative angular displacement occurs with too great a difference in taper
Solution Approach 1:
The crown is divided into an outer part and an inner part that can be assembled separately. The indexing means are provided on the inner part, allowing precise angular orientation to be established during assembly and then maintained through the clamping mechanism without requiring perfect conicity matching throughout the entire structure.
Solution Approach 2:
The indexing means (protrusions and recesses) are pre-configured on the inner part to establish the desired angular orientation before the final clamping operation. This preliminary positioning ensures that when the parts are clamped together, the distinctive sign is already in the correct angular position, eliminating the need for perfect conicity matching during the clamping process itself.
2Reliability
If a flat gasket is interposed between the crown and tube, then sealing is achieved, but the precision of angular orientation is limited due to compression dependence on screwing degree
Solution Approach 1:
The sealing function is separated from the angular orientation function. The indexing means on the inner part establish angular orientation independently, while the flat gasket provides sealing at the interface between the crown assembly and tube. This segmentation allows each function to be optimized independently without compromising the other.
Solution Approach 2:
The angular orientation is preliminarily established by the indexing means (protrusions and recesses) on the inner part before the crown is screwed onto the tube. This preliminary angular positioning ensures that the distinctive sign achieves its determined angular orientation independently of the compression force applied by the flat gasket during screwing.
3Manufacturing precision
If a nut is used to lock the threaded ring, then angular positioning can be achieved, but the solution is difficult to implement industrially due to tightening torque and requires specialized tools
Solution Approach 1:
The angular positioning function is integrated into the inner part of the crown through pre-configured indexing means (protrusions and recesses), rather than requiring a separate locking mechanism like a nut. This integration simplifies the assembly process and eliminates the need for specialized tools or complex locking operations during industrial manufacturing.
Solution Approach 2:
The inner part of the crown is designed with self-indexing capabilities through its own protrusions and recesses that automatically engage with corresponding features on the outer part. This self-indexing mechanism eliminates the need for external locking devices or specialized tooling, allowing workers to simply assemble the parts without requiring expertise in angular positioning or specialized equipment.
4Manufacturing precision
If elastic braking means are used to orient the decorative element, then angular orientation is achieved, but the junction remains visible and the element can be moved accidentally
Solution Approach 1:
The angular orientation function is integrated into the structural core of the crown (the inner part) rather than being a separate decorative element. The indexing means are built into the inner part itself, ensuring that the distinctive sign achieves precise angular orientation as an integral part of the crown structure, not as an add-on that could become visible or loose.
Solution Approach 2:
The angular orientation mechanism is merged with the structural inner part of the crown. The protrusions and recesses are formed as integral features of the inner part, combining the aesthetic function (holding the distinctive sign) with the positioning function in a single unified component, eliminating visible junctions and accidental movement risks.
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
The solution ensures precise and reproducible angular orientation of the distinctive sign, maintaining its position even after multiple screwings and unscrewings, without visible junctions or accidental movement, and is industrially feasible without requiring specialized tools or temperature changes.
Implementation Method 1
a coil spring (6) intended to come into engagement with an internal face of the bottom of the external part, the coil spring being capable of exerting a force on the clamping ring in order to enable the clamping ring to be expanded and contracted
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
This watch case comprises a middle (1), a tube (3, 23), which is secured to the middle (1) and is provided with a thread, a control crown (C) which is provided with a thread screwed onto the tube (3, 23), the control crown (C) having an external part (10, 20) that has a distinctive mark (S) that is visible from the outside and an internal part (2, 24) housed inside the external part (10, 20) and clamping means (11) for axially holding said external part (10, 20) and said internal part (2, 24) in an angular position determined with respect to the longitudinal axis of said tube. The internal part (2, 24) has first angular indexing means (2a, 24a), the external part (10, 20) having second angular indexing means (10a, 20a), these indexing means being shaped so as to engage axially in one another.