Timepiece Glass or Dial Fastening with Stress-Absorbing Spacers
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Solution Overview
Problem
Existing methods for fixing fragile watch components, such as sapphire dials, are inadequate due to material limitations and manufacturing tolerances, leading to potential breakage and difficulty in assembly.
Innovation Solution
A fastening device with a spacer element is used between the component and the fixing element, allowing for screws to secure fragile components like sapphire dials without direct contact, using spacers made of various materials to absorb stresses and maintain positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional fixing methods (screws, feet, or mounting on outer diameters) are used for sapphire dials, then assembly is simplified, but the fragile sapphire material breaks due to tightening stresses and pressing forces
Solution Approach 1:
The patent introduces an intermediary element (adhesive layer or elastic spacer) between the dial and the fixing structure. This intermediary absorbs the tightening stresses and pressing forces, preventing direct transmission to the fragile sapphire dial while maintaining secure attachment. The intermediary acts as a buffer that protects the dial from mechanical damage during assembly and operation.
2Ease of manufacture
If sapphire dials are drilled with wider manufacturing tolerances, then manufacturing becomes easier, but conventional assembly methods fail due to misalignment and improper fit
Solution Approach 1:
The patent changes the parameters of the fixing system by introducing compliant elements (elastic spacers or adhesive layers) that can accommodate variations in hole diameter and position. This allows the system to tolerate wider manufacturing tolerances in the drilled holes while maintaining proper alignment and secure attachment, eliminating the need for tight tolerance drilling.
3Strength
If screws are tightened directly against sapphire dials, then fastening strength is maximized, but the dial breaks due to concentrated stresses
Solution Approach 1:
The patent applies beforehand cushioning by placing an elastic spacer or adhesive layer between the screw head and the sapphire dial before tightening. This cushioning element distributes the concentrated stress from the screw over a larger area and absorbs the tightening forces, preventing stress concentration that would cause the fragile dial to break while still maintaining adequate fastening strength.
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 effectively secures fragile components without damage during assembly and disassembly, ensuring resistance to breakage and maintaining positional integrity.
Implementation Method 1
at least one spacer (4), arranged to be inserted between the component (1) and the fixing element (3), and to maintain them at an axial and radial distance from each other, and to support an axial force resulting from the cooperation between the fixing means (20) and the complementary fixing means (30)
Data Source
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AI summary
The present invention relates to a fastening device (10) for a watchmaking structure (2) equipped with at least one fastening means (20), for a component (1) having at least one through hole (11), having at least one fastening element (3) dimensioned to be inserted into the hole (11) with a non-zero radial clearance, this fastening element (3) having a complementary fastening means (30) arranged to cooperate in a complementary manner with a fastening means (20) of the structure (2), this device (10) having at least one spacer (4) arranged to be inserted between the component (1) and the fastening element (3) and to maintain them at an axial and radial distance from each other, and to support an axial force resulting from the cooperation between the fastening means (20) and the complementary fastening means (30) when the fastening element (3) is in its position closest to the structure (2),the component (1) is at a distance from said structure (2) when said fastening element (3) is in its position closest to said structure (2).