Watch Dial Shock Resistance via Segmented Plate Design
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Solution Overview
Problem
Watch dials made of fragile materials like mother-of-pearl or aventurine are prone to cracking or breaking upon shock, failing to meet shock resistance standards such as Swiss watch industry standard NIHS 91-10 due to uneven stress distribution during radial or vertical impacts.
Innovation Solution
A dial structure comprising two plates of different dimensions, where a larger support plate with a peripheral rim absorbs shocks, allowing the fragile plate to move freely and reducing stress, with distinct radial play for each plate to mitigate impact stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fragile plate is mounted with the same play as the support plate, then the dial structure is simple, but the fragile plate is stressed during shock and liable to crack or break
Solution Approach 1:
The dial is segmented into two distinct plates (support plate and fragile plate) with different functions. The support plate handles shock absorption while the fragile plate provides aesthetic appearance. This segmentation allows each plate to be optimized for its specific purpose, resolving the contradiction between structural simplicity and shock resistance.
Solution Approach 2:
Different play values are assigned to different parts of the dial structure. The fragile plate is mounted with greater radial play than the support plate, creating localized differences in mechanical behavior. This local quality adjustment ensures the fragile plate is protected during radial shocks while maintaining overall structural integrity.
2Object-affected harmful factors
If the fragile plate is mounted facing the bezel with play to absorb vertical shocks, then vertical shock absorption is improved, but the fragile plate collides with the bezel and is stressed
Solution Approach 1:
The support plate acts as an intermediary between the fragile plate and the bezel during vertical shocks. It absorbs the impact force first, preventing direct collision between the fragile plate and the bezel. This mediator approach protects the fragile plate while still providing vertical shock absorption.
Solution Approach 2:
The support plate provides beforehand cushioning by being positioned between the fragile plate and external shock sources. It is designed to absorb shocks before they can reach the fragile plate, preventing stress concentration on the fragile material.
3Device complexity
If the edges of the plates are vertically aligned, then the dial structure is conventional and simple, but both plates butt against the case middle during radial shock
Solution Approach 1:
The edges of the support plate and fragile plate are deliberately misaligned, creating an asymmetric structure. This asymmetry allows different radial play values for each plate, enabling the fragile plate to move freely during radial shocks while the support plate provides structural support and absorbs the impact.
Data Source
AI summary
A dial to be mounted in a watch case includes a first support plate and a second fragile plate, the two plates defining a horizontal plane and being bonded one on top of the other in a vertical direction relative to the horizontal plane. The second plate has a smaller section in the horizontal plane than the section of the first plate in order to leave free on the first plate a peripheral rim to be mounted with play inside the watch case.