Diving Watch Case Sealing With Conical Crystal Support
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Solution Overview
Problem
Existing water-resistant watch cases fail to maintain effective water resistance during dives to large depths due to inadequate pressure handling, as traditional sealing methods are insufficient to withstand high water pressures.
Innovation Solution
A water-resistant watch case design featuring conical bearing surfaces on the crystal and middle part, combined with a gasket system that includes a metal alloy for enhanced stress distribution and a polymer component for additional strength, ensuring the crystal and middle part are securely fastened and resistant to pressure-induced deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sealing methods with simple packings are used, then the watch case can be assembled easily, but the water resistance cannot be guaranteed during dives to very large depths
Solution Approach 1:
The sealing structure is divided into multiple functional components: a first packing element for sealing between the back and middle part, a second packing element for sealing between the crystal and middle part, and a dome structure for pressure equalization. Each component performs a specific sealing or pressure management function, allowing the system to maintain water resistance while managing complexity through functional segmentation.
Solution Approach 2:
The dome structure is pre-assembled within the case before final assembly, creating a pre-configured pressure management system. The dome is positioned to receive and distribute water pressure forces before they reach the crystal and back, providing preliminary protection against pressure-induced deformation during deep dives.
2Strength
If the crystal is fastened with traditional methods, then the assembly is simple, but the crystal may break or thickness may reduce under high water pressure
Solution Approach 1:
A second packing element serves as an intermediary component between the crystal and the middle part. This packing element distributes the clamping forces and water pressure forces over a larger area of the crystal, preventing stress concentrations that could lead to breakage or thinning. The intermediary packing absorbs and redistributes mechanical stresses, protecting the crystal while maintaining a relatively simple fastening structure.
3Ease of manufacture
If the back is fastened by screwing to internal tapping, then assembly is straightforward, but the tapping can be damaged at high water pressure
Solution Approach 1:
The dome structure is installed and pre-configured within the case before final assembly, creating a protective barrier that receives water pressure forces first. This preliminary arrangement ensures that when the watch is subjected to high water pressure, the dome absorbs and distributes these forces before they reach the screwed back and its internal tapping, preventing damage to the tapping while maintaining straightforward assembly procedures.
Solution Approach 2:
The dome structure acts as a cushioning element positioned beforehand to absorb and distribute water pressure forces. This prior cushioning protects the vulnerable internal tapping of the screwed back from direct exposure to high water pressures, preventing damage while allowing the use of simple screwed fastening methods for assembly.
4Strength
If conventional gasket materials are used, then manufacturing is simple, but stress distribution is insufficient preventing plasticization of the middle part
Solution Approach 1:
The sealing system uses different packing materials optimized for specific functions: the first packing element uses a material suitable for withstanding compression between the back and middle part, while the second packing element uses a material optimized for sealing against the crystal and distributing stresses uniformly. This composite approach to material selection enhances stress distribution capability and prevents plasticization of the middle part, while each individual packing can still be manufactured using conventional methods.
Data Source
AI summary
A water-resistant watch case of a diving watch, includes a back mounted on a lower side of a middle part, and a crystal mounted on an upper side of the middle part. The crystal includes an annular peripheral surface mounted by a first portion of an annular gasket made of amorphous metal on an inner annular surface that is complementary in shape, on the upper side of the middle part. A second portion of the gasket on the first portion of the gasket maintains the crystal against the middle part. The annular peripheral surface of the crystal is inclined towards the inside of the watch case at an angle less than 90° relative to a central axis perpendicular to the plane of the watch case to distribute stresses between the crystal and the middle part due to the water pressure.