Alternating Escapement Wheels for Watchmaking Efficiency

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Solution Overview

Problem

Existing watchmaking exhaust systems, such as the Swiss anchor and Robin type exhausts, have relatively low mechanical efficiency, typically around 30% to 40%, due to high energy expenditure during clearance phases and inefficient energy transmission.

Innovation Solution

The proposed watchmaking exhaust system improves mechanical efficiency by optimizing the layout and geometry of the exhaust mobiles and blocker, minimizing the clearance energy required and maximizing energy transmission through a direct impulse mechanism, resulting in higher yields of up to 120% to 160% compared to conventional systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional escapement devices (Swiss lever or Robin type) are used, then the structure is simple and easy to manufacture, but the mechanical efficiency is low (30% to 40%) due to high energy expenditure during clearance phases

Engineering Contradiction:
Improvemechanical efficiencyVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The escapement device is divided into two independent escape wheels (first escape wheel and second escape wheel) that operate in alternation. This segmentation allows one wheel to be in impulse phase while the other is in clearance phase, effectively halving the energy expenditure during clearance and improving mechanical efficiency from 30-40% to 120-160%.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The two escape wheels rotate in opposite directions and alternate their impulse and clearance phases periodically. This periodic action ensures that while one wheel is delivering impulse to the oscillator, the other is clearing without significant energy loss, creating a continuous efficient operation cycle.

Inventive Principle:
Principle #19Periodic action

2Loss of energy

If the clearance energy is minimized and direct impulse mechanism is used, then mechanical efficiency increases to 120% to 160%, but the layout and geometry optimization becomes more complex

Engineering Contradiction:
Improveclearance energyVSAvoidlayout and geometry optimization
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

Different geometric configurations are applied to different parts of the escapement system. The escape wheels have specifically designed tooth profiles and angles optimized for their respective functions (impulse delivery vs. clearance). The blocker and impulse surfaces have localized geometric features that minimize clearance energy while maximizing impulse transmission efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention optimizes specific geometric parameters such as the angle of impulse surfaces, tooth profiles, and relative positions of escape wheels and blocker. These parameter changes are carefully tuned to minimize clearance energy expenditure while maintaining manufacturability through precise but achievable geometric specifications.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If direct impulse mechanism is used to maximize energy transmission, then mechanical efficiency improves, but disturbances to the oscillator increase

Engineering Contradiction:
Improveenergy transmission efficiencyVSAvoidoscillator stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The harmful disturbances to the oscillator are extracted and isolated by using a separate second escape wheel dedicated to clearance operations. This wheel operates independently without directly disturbing the oscillator, while the first escape wheel provides clean impulse delivery. This separation removes the source of disturbances while maintaining high energy transmission efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3394682B1Timepiece escapement device and operating method of such a device
Publication Date: 2025.04.30 ROLEX SA
  • EP3394682B1 patent drawingFigure 1
  • EP3394682B1 patent drawingFigure 2
  • EP3394682B1 patent drawingFigure 3

AI summary

The invention relates to an escapement device (400) comprising a first escapement wheel (1), a second escapement wheel (2), and a brake-lever (3), said second escapement wheel being disposed between the first escapement wheel and the brake-lever, in particular the second escapement wheel coming into contact and engaging with both the first escapement wheel and the brake-lever.