Multi-Stage Differential for Timepiece Balance
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Solution Overview
Problem
Conventional differentials with three inputs and one output become unbalanced and may cease to function if one of the pendulums oscillates at a frequency different from the others, leading to poor force distribution and potential shutdown of the watch.
Innovation Solution
A differential mechanism with an input/output shaft and multiple rotary members, including satellites, is designed to distribute excess force between outputs, ensuring the system remains balanced even if one or two outputs stop, by incorporating additional stages that connect the first and second stages, allowing continued operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional differential with three inputs and one output is used, then the system can average the speeds of rotation of three barrels, but the system becomes unbalanced and may cease to function if one of the pendulums oscillates at a different frequency
Solution Approach 1:
The differential is segmented into multiple independent stages (first stage with first satellite, second stage with second satellite, third stage with third satellite), where each stage processes one input independently. This segmentation allows each stage to operate autonomously, preventing imbalance propagation when one pendulum oscillates at a different frequency, thus maintaining system reliability while preserving speed averaging capability.
2Adaptability or versatility
If one pendulum oscillates at a frequency different from the others, then frequency variation is allowed, but force distribution becomes poor and the watch may shut down
Solution Approach 1:
The third satellite stage acts as an intermediary between the first and second stages, redistributing forces from all three inputs through its meshing with both first and second satellites. This intermediary mechanism ensures balanced force distribution to the single output even when input frequencies differ, allowing frequency variation tolerance without compromising force distribution or causing shutdown.
3Adaptability or versatility
If a differential with one input and three outputs is designed, then three balance wheels can be powered by the same source, but the system becomes unbalanced as soon as one pendulum oscillates at a different frequency
Solution Approach 1:
The differential employs dynamic force redistribution through its multi-stage planetary gear mechanism. Each satellite stage dynamically adjusts force distribution based on the instantaneous oscillation frequencies of the connected pendulums. This dynamic adaptation maintains system balance even when one pendulum oscillates at a different frequency, enabling power distribution to multiple oscillators without compromising stability.
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
The mechanism allows the different oscillators to oscillate at various frequencies and maintains watch functionality by distributing forces effectively, preventing shutdown when one or two outputs cease operation.
Implementation Method 1
a first satellite associated with the first rotary member and forming with the latter a first stage of the differential, a second satellite associated with the second rotary member and forming with the latter a second stage of the differential connected to the first stage by the third rotary member
Data Source
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AI summary
The differential according to the invention comprises an input/output shaft (2; 21); a first, a second, a third and a fourth rotating member (6, 8, 10, 11; 24, 26, 28, 29) mounted movable around the shaft and relative to each other, the first and second rotating members (6, 8; 24, 26) defining respectively a first and a second output/input (6a, 8a; 24a, 26a) of the differential, the third or fourth rotating member (10, 11; 28, 29) defining a third output/input (10a; 26a) of the differential; a first satellite (7; 25) associated with the first rotating member (6; 24) and forming with the latter a first stage of the differential; a second satellite (9; 27) associated with the second rotating member (8; 26) and forming with the latter a second stage of the differential connected to the first stage by the third rotating member (10; 28); and a third satellite (12; 31) associated with the fourth rotating member (11;29) and forming with the latter a third stage of the differential, this third stage connecting the first and second stages to each other. A planetary version and a spherical version of this differential are proposed.