Watch Case Bayonet Connection With Elastic Locking Tab
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing watch case bayonet connections are complex to manufacture, costly, and difficult to assemble correctly, with variability in quality depending on operator skill, and there is a risk of damage during locking due to unclear positioning and potential over-tightening.
Innovation Solution
A bayonet connection with an elastic fitting tab and clearance configuration that generates a resistant torque, providing sensory feedback for correct locking and ensuring precise orientation and watertight sealing through elastic deformation and a progressive slope obstacle, allowing reversible assembly without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bayonet connection is used to assemble the case back to the case body, then precise orientation and reliable locking are achieved, but the structure becomes complex and requires additional elastic closure elements
Solution Approach 1:
The patent combines the elastic closure element and the locking tab into a single integrated component. The elastic element is formed as part of the case back structure itself, eliminating the need for separate elastic closure elements while maintaining the bayonet connection's reliable locking function.
Solution Approach 2:
The case back structure serves multiple functions: it provides the sealing surface, the locking mechanism, and the elastic closure function all in one component. The integrated elastic locking tab performs both sealing and locking operations, reducing overall device complexity.
2Manufacturing precision
If a bayonet connection with additional elastic closure elements is used, then precise orientation is ensured, but the cost and size of the case increase
Solution Approach 1:
The patent merges the elastic closure element with the case back structure, creating a single-component solution that maintains precise orientation capabilities while eliminating additional parts, thereby reducing manufacturing complexity and cost.
3Manufacturing precision
If manual pre-positioning is used with press-fit assembly, then operator skill determines accuracy, but the process is simple and cost-effective
Solution Approach 1:
The bayonet connection with integrated elastic locking tab provides self-aligning and self-locking functionality. The elastic element automatically engages with the locking groove at the correct orientation, eliminating the need for manual pre-positioning and reducing dependence on operator skill.
4Ease of operation
If a screw-on case back is used, then assembly is simple, but it is difficult to determine if the gasket is sufficiently compressed for a proper seal
Solution Approach 1:
The elastic locking tab provides tactile feedback to the operator during assembly. When the tab engages with the locking groove, the operator can feel the distinct click or resistance change, providing immediate feedback that the case back is correctly positioned and the gasket is properly compressed.
5Manufacturing precision
If a bayonet connection is used, then precise orientation is achieved, but it is difficult to know if the case back is correctly positioned in the locking position
Solution Approach 1:
The integrated elastic locking tab provides clear tactile feedback when engaged in the locking position. The operator can detect the correct positioning through the distinct engagement sensation, eliminating uncertainty about whether the case back is properly locked.
6Reliability
If excessive force is applied during locking, then the case back may be damaged, but adequate force is needed to ensure proper sealing
Solution Approach 1:
The elastic locking tab acts as a cushioning element that absorbs excess force. When the case back is being locked, the elastic element compresses to provide a progressive resistance, preventing sudden excessive forces that could damage the case back while ensuring adequate sealing pressure.
Solution Approach 2:
The elastic locking tab changes the force parameter from a sudden high-force application to a progressive compression. The elastic element gradually compresses during locking, distributing the force over time and preventing peak forces that could cause damage while maintaining adequate sealing pressure.
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 ensures precise orientation and correct locking of the case back, prevents accidental disassembly, and maintains watertightness while being cost-effective and space-efficient, with sensory feedback for correct assembly.
Implementation Method 1
said elastic portion is configured to deform elastically when the elastic locking tab encounters the obstacle during a relative rotation of the case and the case back around the axial direction
Implementation Method 2
the bayonet joint is configured to ensure an elastic fit generating a resisting torque tending to oppose a relative rotation of the case and the case back
Implementation Method 3
The obstacle includes a deformation ramp having a progressive slope configured to progressively deform, in an elastic manner, the elastic portion carrying the elastic locking tab during the relative rotation
Data Source
Figure 1~2
Figure 3~5
AI summary
One aspect of the invention relates to a watch case (100) comprising a case middle (110) and a case back (120) assembled by a bayonet joint by relative rotation of the case middle (110) and the case back (120) around an axial direction (D), characterized in that said bayonet joint is configured to ensure an elastic fit generating a resisting torque tending to oppose a relative rotation of the case middle (110) and the case back (120), said bayonet joint comprising an elastic fitting tab (130) formed at the level of an elastic portion (123) of said case back (120), said elastic fitting tab (130) being configured to cooperate with a clearance (140) formed in the thickness of the case middle (110),said clearance (140) comprising an obstacle (143) locally limiting the depth of said clearance (140) in a radial direction relative to the axial direction (D) and configured to form a hard point when the elastic locking tab (130) encounters the obstacle (143) during a relative rotation of the case (110) and the case back (120) around the axial direction (D).