Monolithic Drive Finger and Leaf Spring Assembly for Timepiece
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Solution Overview
Problem
Existing drive mechanisms for timepieces, such as those used for displaying date, day of the week, or month, face challenges in assembly and adjustment due to the need for precise operations and sufficient material thickness for axial holding and guiding return springs, and flexible elements like leaf springs are prone to deformation and energy loss, making it difficult to drive mobiles over large angular pitches.
Innovation Solution
A drive mechanism featuring a monolithic drive finger and leaf spring assembly, where the leaf spring only intervenes for retraction and does not deform during driving, allowing the finger to pivot freely and resume driving position without deforming, facilitating easy assembly and enabling drive over large angular pitches on a rigid element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return spring is used to keep the finger in contact with the pin, then the finger can be held in position to resume driving, but the assembly and adjustment become delicate and require several precise operations with sufficient material height/thickness
Solution Approach 1:
The patent combines the return spring and the guiding pin into a single monolithic component. The pin is formed with an integrated return spring that has a first end fixed to the pin body and a second end that engages the finger, eliminating the need for separate assembly operations and reducing structural complexity while maintaining the finger contact function.
Solution Approach 2:
The pin component serves multiple functions: it acts as both a guiding element for the finger and a mounting structure for the integrated return spring. This multi-functional design eliminates the need for separate guiding pins and return spring assemblies, simplifying both the structure and assembly process.
2Ease of operation
If a leaf spring is used to retract the driving finger, then the finger can be retracted during reverse rotation, but the spring must be dimensioned to overcome positioning jumper and impacts the energy of the mechanism
Solution Approach 1:
The patent extracts the retraction function from a separate leaf spring and integrates it into the pin component. The return spring on the pin provides the retraction force locally where needed, eliminating the need for a separate dimensioned leaf spring that would impact the overall mechanism energy.
Solution Approach 2:
The integrated return spring on the pin acts as an intermediary that provides localized retraction force without requiring a separate energy-storing leaf spring. This mediator component achieves finger retraction during reverse rotation while minimizing impact on the overall mechanism energy.
3Ease of operation
If a flexible element is used to drive the mechanism, then retraction is possible, but driving over large angular pitches becomes difficult and requires precise force balance
Solution Approach 1:
The patent merges the driving pin and return spring into a single component, creating a rigid driving element with an integrated flexible retraction element. This combination allows large angular pitch driving with the rigid pin while the integrated spring provides automatic retraction without requiring precise force balance calculations.
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 solution simplifies assembly and adjustment, reduces stress on the leaf spring, and allows efficient driving over large angular pitches without energy loss, as the leaf spring only assists in retraction, maintaining the drive mechanism's performance and longevity.
Implementation Method 1
the leaf spring returns the finger to a position in which it can resume driving the moving part when the normal rotation (in the first direction) of the driving wheel resumes
Data Source
Figure 1
AI summary
The present invention relates to a drive mechanism for equipping a movement in a timepiece. In particular, the present invention relates to such a mechanism comprising a finger for driving a moving part, notably a star wheel, said finger being carried by a driving part, notably a driving wheel, and arranged to be disengageable.