Dual-Spring Large Rocker Mechanism for Perpetual Date Accuracy
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Solution Overview
Problem
Existing perpetual and secular calendar mechanisms face difficulties in accurately and reliably transitioning date displays due to the strong return spring of the large rocker, leading to inconsistent and hard-to-regulate movements, especially when transitioning from months with 28 or 29 days to the next month, causing potential over-jumps in date indicators.
Innovation Solution
The mechanism employs a dual-spring system for the large rocker, with one spring maintaining the rocker in the rest position and another providing a substantially constant torque for its fall, eliminating the need for a regulator and dissipator device, ensuring consistent and accurate date transitions by adjusting the positioning and characteristics of the springs relative to the rocker's pivot axis and through pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single strong return spring is used to arm the large rocker for 24 hours, then the rocker has sufficient force to advance the date display by one or more steps, but the strong force causes the date indicator to jump one or two steps too far when transitioning from months of 28 or 29 days
Solution Approach 1:
The single return spring is divided into two separate springs: a first return spring that arms the large rocker for 24 hours and a second return spring that provides a constant torque during the fall. This segmentation allows each spring to have optimized characteristics for its specific function, preventing the over-jump problem while maintaining sufficient force.
Solution Approach 2:
The invention changes the parameter characteristics of the return mechanism by introducing a second spring with substantially constant torque. This modifies the force profile during the rocker's fall, transforming it from a high-force variable torque system to a controlled constant torque system that prevents excessive date jumps.
2Reliability
If the amplitude of the winding stroke is increased to ensure sufficient force for date transition, then the date display can transition reliably, but the mechanism becomes harder to regulate and adjust
Solution Approach 1:
By segmenting the return spring function into two independent springs with different characteristics, the invention simplifies adjustment and regulation. Each spring can be independently optimized and adjusted, making the mechanism easier to regulate while maintaining reliable date transitions.
Solution Approach 2:
The dual-spring system provides self-regulating characteristics where the first spring automatically arms the rocker for the appropriate duration and the second spring automatically provides constant torque during fall, reducing the need for complex external regulation and adjustment mechanisms.
3Manufacturing precision
If a regulator and dissipator device are added to control the fall speed of the large rocker, then the date indicator jumps are prevented, but the device complexity increases
Solution Approach 1:
The invention extracts and eliminates the need for complex regulator and dissipator devices by using a simpler dual-spring mechanism. The second return spring with substantially constant torque directly prevents over-jumps without requiring additional regulation components, thereby reducing device complexity.
Solution Approach 2:
The invention replaces complex mechanical regulation and dissipation systems with a simpler spring-based torque control system. The second return spring provides the necessary torque control through its elastic properties alone, substituting the need for complex mechanical regulators and dissipators.
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 ensures reliable and easy adjustment of the calendar mechanism, preventing untimely jumps in date, day, and month indicators, maintaining accurate date transitions without the complexity of regulating the rocker's fall speed.
Implementation Method 1
a first return spring of the large rocker constantly resting on the through pin of the large rocker
Implementation Method 2
a second return spring of the large rocker arranged to provide a substantially constant torque to the large rocker during its fall from its maximum lifted position
Implementation Method 3
a large rocker pivoted around an axis
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The device for actuating in its drop a large rocker for controlling the display of an instantaneous date mechanism of a timepiece having a perpetual or secular date mechanism comprises a device for setting the large rocker to an angular value that is a function of the number of days in a given month and causing it to drop once per day, this large rocker driving a date indicator one step per day from the first to the penultimate day of a month and by one, two, three or four steps at the end of a month, depending on whether this month has thirty-one, thirty, twenty-nine or twenty-eight days. This device comprises at least one first return spring (26) for returning the large rocker (2) in its drops, its end resting permanently on a pin (24) belonging to the large rocker and being fixed to a date plate (1) in such a position relative to this pin (24) and to the pivot arbor (3) of the large rocker, that the lever arm applying the force of this first return spring (26) to the large rocker decreases as a function of the angular setting travel of this large rocker and therefore of said first return spring (26).