Timepiece Rocker Arm Mechanism for Star Wheel Return
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Solution Overview
Problem
Existing actuation mechanisms in timepieces, such as calendar watches, face issues with mechanical stress and torque-induced deformation, leading to potential breakage or phase shifts during date indicator adjustments, especially around midnight, and one-way drive mechanisms cause index loss and prevent return to the rest position.
Innovation Solution
The actuation mechanism features a flexible arm with a proximal portion oriented radially and a rigid arm with a tangential bearing surface, allowing the flexible arm to push a star wheel tooth while maintaining alignment, and a flexible arm that can flex to return to the rest position despite torque resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rigid actuation arm is used to push the star wheel tooth, then the pushing force is transmitted effectively, but the mechanism cannot return to the rest position due to torque resistance from the star wheel
Solution Approach 1:
The actuation arm changes its physical state from rigid to flexible, allowing it to deform under torque and return to its rest position after actuating the star wheel, thereby resolving the contradiction between effective force transmission and return capability
Solution Approach 2:
The actuation arm transitions from a static rigid structure to a dynamic flexible structure that can adapt its shape during operation, enabling it to push the star wheel tooth effectively and then return to its original position by flexing
2Shape
If the flexible arm is positioned on the rear side of the actuating arm, then the structure is compact, but the end of the flexible arm shifts out of the pivot plane causing misalignment with the star teeth
Solution Approach 1:
The flexible arm is repositioned from the rear side to the front side of the actuating arm, creating an asymmetric configuration that maintains proper alignment of the flexible arm end with the star teeth while avoiding the misalignment issues caused by the previous symmetric rear-side positioning
3Reliability
If one-way drive mechanisms are used to prevent breakage during date adjustment, then mechanical breakage is prevented, but the index is lost and the corrector cannot return to its rest position
Solution Approach 1:
The actuation arm changes from rigid to flexible, allowing it to deform and return to its rest position after actuating the star wheel, thereby enabling the corrector to reset while maintaining mechanical reliability through the flexible connection
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 proper functioning and alignment of the actuation mechanism, preventing breakage and phase shifts, while allowing seamless return to the rest position without pushing the star wheel backward.
Implementation Method 1
the flexible arm comprising a proximal part oriented substantially radially with respect to the pivot axis of the rocker, and a second part which is oriented transversely with respect to the proximal part and separated from the latter by a bend
Data Source
Figure 1A~1B
Figure 2~4
AI summary
The actuation mechanism comprises a rocker arm (17) splitting into two branches (29, 31), one branch being flexible and the other rigid. The flexible branch (29) is located on the front side of the actuation arm (17) when the rocker pivots from its rest position to its fully tilted position, and its end (37) is arranged to push a tooth of a star (21). The flexible branch (29) further includes a support area designed to bear against a bearing surface (39) on the rigid branch (31) when the rocker pivots from its rest position to its fully tilted position.