Waterproof Watch Case Compression-Resistant Structure
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Solution Overview
Problem
Existing waterproof wristwatch cases face limitations in depth capability due to material weaknesses and thickness constraints, particularly when trying to withstand pressures of 3 to 4 times higher than current designs, which would require significant thickness increases, making them unwearable.
Innovation Solution
A waterproof wristwatch case design featuring a protective casing with a crystal, side wall, and bottom made from high-modulus materials like ceramic and metal alloys, incorporating a structure resistant to compression and a radial clamping mechanism that separates sealing and pressure resistance, allowing for a total thickness of less than 17.7 mm to withstand pressures up to 50 MPa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the case thickness is increased to withstand higher pressures (3-4 times greater than current designs), then the depth capability is improved, but the wearability and overall thickness become excessive
Solution Approach 1:
The patent divides the case into three distinct functional layers: an outer decorative case made of traditional materials (gold, silver, plastic), an intermediate bearing surface layer, and an inner compression-resistant cup made of high-strength material (titanium, steel). This segmentation allows each layer to perform its specific function optimally without requiring the entire case to be thick and heavy.
Solution Approach 2:
The invention applies different material properties to different regions of the case. The inner cup uses materials with high compression strength (titanium or steel) specifically where pressure resistance is needed, while the outer case can use aesthetically pleasing but mechanically weaker materials. This localized application of material properties resolves the contradiction between strength and thickness.
2Ease of manufacture
If a lower-strength material is used on the case positioned between the lens and inner bezel, then manufacturing ease and aesthetics are improved, but the structural integrity under high pressure deteriorates
Solution Approach 1:
The case is segmented into an outer decorative portion that can be easily manufactured from traditional materials and an inner functional cup that provides compression resistance. This segmentation allows each part to be optimized for its specific purpose without compromise.
Solution Approach 2:
The invention uses a composite structure combining traditional watch case materials (gold, silver, plastic) for the outer case with high-strength materials (titanium, steel) for the inner pressure-resistant cup. This composite approach allows the case to achieve both aesthetic/manufacturing advantages and structural integrity.
3Length of stationary object
If the bearing surface is made thinner to reduce overall case thickness, then wearability is improved, but the risk of permanent damage under high pressure increases
Solution Approach 1:
The bearing surface function is segmented from the decorative case and assigned to a dedicated inner cup structure. This allows the bearing surface to be optimized for strength and pressure distribution without being constrained by aesthetic or thickness requirements of the outer case.
Solution Approach 2:
The inner cup acts as a pre-positioned protective structure that distributes and absorbs compressive forces before they can damage the bearing surface or movement. This 'cushioning' structure is built in advance to prevent damage under high pressure.
4Ease of manufacture
If the bezel portion resting against the case-bezel support is cantilevered, then manufacturing simplicity is improved, but the transmission of compressive force deteriorates
Solution Approach 1:
The bezel is segmented into an outer decorative bezel and an inner functional structure. The inner cup provides a solid, non-cantilevered support structure that properly transmits compressive forces, while the outer bezel maintains aesthetic and manufacturing simplicity.
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 design enables the watch case to reach depths of several thousand meters while maintaining a wearable thickness, with the sealing and pressure resistance mechanisms functioning independently, reducing the overall thickness by approximately 10% compared to conventional designs.
Implementation Method 1
a flat peripheral surface extending over the entire edge of the inner face of the crystal is in contact with a corresponding bearing surface of the side wall, at least a portion of which forms the width of the cross-section of a compression-resistant structure with parallel side faces, perpendicular to the bearing surface
Implementation Method 2
means for radially clamping this gasket against these portions of constant cross-section of the crystal and the case's side wall
Implementation Method 3
the components of the crystal and the case back are made of materials having a Young's modulus > 100,000 MPa and a flexural strength > 500 MPa, the material of the compression-resistant structure having a Young's modulus > 100,000 MPa and a compression strength > 500 MPa
Data Source
Figure 1
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AI summary
This watch case comprises a protective casing surrounded by a case middle (5) and a bezel (9). The protective casing includes a crystal (3), a side wall (2), and a case back (1). A flat peripheral surface extending along the entire edge of the inner face of the crystal is in contact with a corresponding bearing surface of the side wall (2), at least a portion of which forms the cross-sectional width of a compression-resistant structure with parallel lateral faces (SR), perpendicular to the bearing surface, and extending continuously to the case back (1). Means for securing and sealing the casing elements include at least one annular gasket (4) surrounding the lateral face of the crystal (3) and the outer lateral face of the side wall (2) of the casing, and means for radially clamping this gasket (4, 5a).