Leaf Spring Torque Indicator for Watch Barrel
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Solution Overview
Problem
Existing dynamometric devices for indicating the torque reserve of a watch mechanism's barrel spring are complex, costly, and interfere with sensitive components, often providing inaccurate or unreliable power reserve estimates due to neglecting factors like spring relaxation and gear train fouling.
Innovation Solution
A compact dynamometric device using a leaf spring with an elastic arm and a needle indicator, where the leaf spring is fixed to a plate and supports the ratchet pawl, allowing it to deform under torque and display the torque reserve on a graduated scale, avoiding interference with the winding mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a helical compensation spring is used to indicate torque reserve, then the indication mechanism can be implemented, but the spring lacks repetitiveness and reliability
Solution Approach 1:
The patent changes the physical parameters of the spring system by using a flat elastic leaf spring instead of a helical spring, and by pre-stressing the leaf spring to create a stable force field. This parameter change provides repeatable and reliable indication without requiring complex compensation mechanisms.
Solution Approach 2:
The patent employs a composite spring system combining a flat elastic leaf spring with a pre-stress mechanism. This composite approach creates a stable force field that compensates for variations in the mainspring characteristics, providing reliable indication while maintaining simplicity.
2Measurement precision
If existing dynamometric devices are used to indicate torque reserve, then power reserve estimation is provided, but they interfere with sensitive components and provide inaccurate readings
Solution Approach 1:
The patent extracts the indication function from the existing complex dynamometric devices and implements it through a simplified leaf spring mechanism that operates independently. The leaf spring's free end directly indicates torque reserve without interfering with the winding mechanism or other sensitive components.
Solution Approach 2:
The patent introduces a free-stressing leaf spring as an intermediary element between the mainspring and the indication system. This leaf spring acts as a mediator that transfers torque information to the indicator without creating harmful interactions with the winding mechanism.
3Reliability
If a complex dynamometric device is implemented, then torque reserve indication is achieved, but the device is costly and requires meticulous assembly
Solution Approach 1:
The patent merges the indication function with the existing ratchet pawl support structure by mounting the leaf spring on the pawl support. This integration eliminates the need for separate complex indication mechanisms, reducing manufacturing cost and assembly complexity while maintaining reliable torque indication.
Solution Approach 2:
The patent makes the ratchet pawl support structure multi-functional by using it to mount both the ratchet pawl and the free-stressing leaf spring. This universal use of existing components simplifies the overall device and reduces the number of parts requiring meticulous assembly.
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
Provides a reliable, simple, and compact indication of the torque reserve without disturbing the watch's operation, ensuring accurate power reserve estimation and avoiding over-winding or under-winding issues.
Implementation Method 1
capable of deforming under the action of a torque
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a dynamometric device (100) indicating the torque reserve of a watch part comprising a barrel ratchet (2) cooperating with a ratchet pawl (3) to maintain accumulated, in a barrel spring, the energy transmitted by a winding crown, said pawl (3) movable by pivoting about an axis (10), between an engagement position where a tooth (31) of the ratchet pawl (3) cooperates with said ratchet (2), and a disengagement position where each tooth (31) of said pawl (3) disappears before the rotation of the ratchet (2) during a winding maneuver of said barrel, said pawl (3) being returned towards said ratchet (2) under the action of a spring (4).It includes a spring blade (1) having an elastic arm (8) fixed to the plate, and said shaft (10) is mounted on a support (12) of said arm (8), at one end of which it has a needle (6) visualizing the torque reserve of the barrel, in cooperation with a torque reserve indicator (5).