Waterproof Watch Case Assembly Rate Stability
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Solution Overview
Problem
The assembly of waterproof timepieces leads to pressure variations within the watch case, causing rate deviations in the movement, which disrupts the chronometric precision and requires complex adjustments to maintain factory settings, especially during after-sales service.
Innovation Solution
A method involving a specific assembly process where the movement is adjusted before casing, with a second element that transitions from a configuration allowing fluid communication to a sealed configuration, minimizing pressure changes and maintaining the movement's rate stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the case back is closed to ensure waterproofing, then water resistance is improved, but pressure increases causing rate deviation in the movement
Solution Approach 1:
The method performs the rate adjustment of the movement before closing the case back, so that the adjustment is made when the movement is still accessible and the case is open. This preliminary action allows the rate to be set correctly before the pressure change occurs when the case is sealed, thereby avoiding the need to reopen the case for adjustments.
Solution Approach 2:
The method involves measuring the rate of the movement both before closing the case back (M1) and after closing the case back (M2), then comparing these measurements. This feedback loop allows for verification that the rate adjustment made before sealing remains accurate after sealing, or enables calculation of the pressure-induced deviation for compensation.
2Manufacturing precision
If the movement is adjusted after casing, then the chronometric precision can be maintained, but the complexity of assembly and maintenance increases
Solution Approach 1:
The rate adjustment is performed as a preliminary action before the case back is closed, making the adjustment process simpler and more accessible. This avoids the complexity of designing and implementing adjustment mechanisms that would need to operate through or around the sealed case back.
Solution Approach 2:
The method enables the movement to self-adjust or be easily adjusted before sealing without requiring complex adjustment mechanisms integrated into the sealed case structure. The adjustment is performed in a straightforward manner when the case is still open.
3Reliability
If the case back is locked to ensure sealing, then waterproofing is improved, but the pressure variation causes rate loss
Solution Approach 1:
The rate adjustment is performed before the case back is locked and sealed, so that the adjustment is made under different pressure conditions. This preliminary adjustment accounts for the fact that the movement will experience pressure changes when the case is sealed, allowing for pre-compensation or accurate baseline setting.
Solution Approach 2:
The method uses feedback from rate measurements taken both before (M1) and after (M2) closing the case back to verify and potentially adjust for pressure-induced rate changes. This feedback mechanism ensures that the final rate accuracy is maintained despite the sealing process.
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
This method ensures that the chronometric precision of the timepiece is maintained by reducing rate variations induced by pressure changes, facilitating easier maintenance and ensuring consistent performance post-assembly.
Implementation Method 1
The pressure inside a waterproof watch case obeys Boyle's Law: p1.V1 = p2.V2
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Method of assembling a timepiece comprising a watch movement and a watertight case, the method comprising the following steps: - a first step of closing the case by placing and locking a first case element, in particular a case back, then - a second step of closing the case by actuating a second case element, in particular a stem, in particular a winding stem or a valve stem or a pusher stem, the second case element being movable between a first configuration in which fluid communication between the inside of the case and an environment outside the case is permitted and a second configuration in which fluid communication between the inside of the case and the environment outside the case is limited, the second closing step being an actuation of the second element moving from the first configuration to the second configuration.