Watch Case Bayonet Connection for Precision Assembly
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Solution Overview
Problem
Existing watch case assembly methods, such as screw threads and elastic tab assemblies, lack precision and reproducibility, and are not robust enough for repeated assembly and disassembly, risking breakage.
Innovation Solution
A bayonet connection system with rigid lugs and grooves, featuring stops for precise positioning and a radial compression joint for secure assembly, eliminating the need for an elastically deformable zone and reducing component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If screw thread assembly is used to connect the back and caseband, then the connection can be secure, but the precision and reproducibility of angular positioning is insufficient
Solution Approach 1:
The connection system is segmented into distinct functional elements: lugs on the back, grooves with clearances in the caseband, and a separate compression seal. This segmentation allows each element to perform its specific function - positioning, guiding, and sealing - independently, achieving precise angular positioning without complex integrated mechanisms.
Solution Approach 2:
A compression seal is introduced as an intermediary element between the back and caseband. This mediator applies radial clamping force to secure the connection while allowing the rigid lug-groove mechanism to handle positioning. The intermediary separates the securing function from the positioning function, improving precision.
2Ease of operation
If elastic tab assembly is used to replace screw thread, then assembly/disassembly becomes easier, but robustness decreases with risk of breakage over time
Solution Approach 1:
Instead of using elastic deformation to achieve connection, the invention inverts the approach by using rigid structures (lugs and grooves) that guide and constrain movement. The elasticity is transferred to the compression seal which deforms radially to provide clamping force, while the primary connection structure remains rigid and break-resistant.
Solution Approach 2:
The invention changes the physical state parameter of the connection system from elastically deformable (tabs) to rigid with controlled compression (seal). The rigid lug-groove structure maintains dimensional stability and resistance to breakage, while the compression seal provides the necessary flexibility for assembly and sealing through radial deformation.
3Reliability
If multiple components are used to ensure secure assembly, then reliability improves, but manufacturing cost and device complexity increase
Solution Approach 1:
The invention merges multiple functions into the compression seal: it provides radial clamping force to secure the connection, ensures watertight sealing between parts, and maintains constant pressure to prevent accidental movement. This consolidation of securing, sealing, and pressure-maintaining functions into a single component reduces overall complexity while improving reliability.
Solution Approach 2:
The compression seal is designed as a multi-functional element that simultaneously performs mechanical securing (through radial clamping), sealing (watertight barrier), and positioning stabilization (preventing accidental movement). This universal component replaces what would traditionally require multiple separate elements, reducing component count while maintaining or improving reliability.
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 bayonet connection provides precise, robust, and reproducible assembly with enhanced security and sealing, minimizing manufacturing costs and component requirements.
Implementation Method 1
a first compression seal applying a clamping force on the first part in a direction perpendicular to the central axis A in the locking position
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a watch case comprising a first part (2) with rims (4) on its outer perimeter, one of the rims (4) comprising a lug (5), and a second part (3) with recesses (9) on its inner perimeter opening onto a groove (7) opening in turn onto a groove (6) delimited at its ends respectively by a first stop (6a) and a second stop (6b), said groove (6) receiving the lug (5) with the first stop (6a) limiting the movement of the lug (5) in the disassembly and assembly positions and with the second stop (6b) limiting the movement of the lug (5) in the locking position, said watch case (1) also comprising a first compression seal (14) applying a radial clamping force on the first part (2) in the locking position.