Watch Mechanism Synchronizing Minute and Second Hands
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Solution Overview
Problem
Existing watch mechanisms lose synchronization between the minute and second hands during the setting process, as the minute hand is decoupled from the power flow, leading to asynchronous operation when the crown is pressed and released.
Innovation Solution
Implementing a dual third wheel group mechanism, where one part is linked to the mainspring barrel and the other to the minute wheel, and a friction clutch to ensure synchronized operation of both hands, along with a locking mechanism using a concentric locking ring and locking pawls for step-by-step minute hand adjustment and a zero setting mechanism involving a pivoted lever and heart-shaped setting curve for precise second hand resetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the minute hand is decoupled from the power flow during setting, then the setting operation can be performed, but the synchronization between minute and second hands is lost
Solution Approach 1:
The third wheel group is divided into two separate parts: one part remains connected to the power flow to drive the second hand, while the other part is connected to the minute wheel for setting operations. This segmentation allows independent control of the two functions, enabling setting without disrupting the power flow and maintaining hand synchronization.
2Ease of operation
If the crown is pulled out for setting, then the minute hand can be adjusted, but the connection between second and minute hands is lost
Solution Approach 1:
The system dynamically reconfigures the gear train connections based on the crown position. When the crown is pulled out for setting, the gear train is reconfigured to allow independent minute hand adjustment while maintaining the second hand's connection to the power flow. When the crown is pushed in, the system automatically synchronizes both hands, dynamically adapting the mechanical connections to maintain reliability during operation.
3Ease of operation
If the minute wheel is turned independently, then setting is possible, but the hands start asynchronously when movement restarts
Solution Approach 1:
An intermediary gear train mechanism is introduced between the minute wheel and the power flow. This intermediary system allows the minute hand to be set independently by turning the crown, while simultaneously maintaining the correct phase relationship with the second hand through the gear ratios. The intermediary mechanism ensures that when the movement restarts, both hands are properly synchronized despite the independent setting operation.
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
Ensures that the minute and second hands start and run synchronously without play, maintaining accurate timekeeping and preventing damage to the watch's components during the setting process.
Implementation Method 1
a friction clutch to ensure synchronized operation of both hands
Implementation Method 2
at least one pivotally mounted locking pawl arranged within the locking ring, which is acted upon radially outwards by a spring element
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The clock has an adjusting shaft (16) coupled with a center-wheel group (40) of a clockwork mechanism such that rotation of the shaft adjusts a minute indicator. The shaft co-operates with an arm (18), intermediate element (20), and zero resetting arm (22) for driving second indicator in a zero position when moving the shaft in an adjusting position. The wheel group includes resting mechanisms that enable 60 resting positions, so that the minute indicator is adjusted between 60 positions of the minute indicator in a minute index by the rotation of the shaft in the adjusting position.