Watch Escapement Non-Planar Peg and Fork Profiles
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Solution Overview
Problem
Conventional watch escapement mechanisms experience slippage and energy losses due to non-optimized geometry of the plate peg and fork assembly, leading to increased wear and reduced efficiency.
Innovation Solution
The introduction of non-planar geometric profiles for the engagement surfaces of the peg and fork, with specific cam portions designed to minimize friction and optimize both release and impulse functions, allowing for a rolling movement without slipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional flat engagement surfaces are used between the peg and fork, then the structure is simple and easy to manufacture, but slippage occurs during release and impulse functions leading to increased wear and energy losses
Solution Approach 1:
The patent applies curved cam profiles to the engagement surfaces of the peg and fork, replacing conventional flat surfaces. The cam portions have specific geometric profiles that enable rolling contact without slipping, thereby reducing energy losses while maintaining manufacturability through precise curvature design
Solution Approach 2:
The patent optimizes the geometric parameters of the cam profiles, including the curvature radii and profile shapes of the engagement surfaces. By carefully selecting and adjusting these parameters, the design achieves minimal slippage and optimal energy transfer efficiency
2Reliability
If conventional flat engagement surfaces are used between the peg and fork, then manufacturing is simple, but wear of parts increases due to slippage and friction
Solution Approach 1:
The curved cam profiles eliminate sliding friction by enabling rolling contact between the peg and fork. This significantly reduces wear of the engagement surfaces, improving reliability and extending the service life of the escapement mechanism
Solution Approach 2:
The cam profiles are designed to dynamically adapt the contact points between the peg and fork during operation. The changing geometry ensures optimal contact conditions throughout the release and impulse cycles, minimizing wear while maintaining ease of manufacture through standardized cam design
3Power
If the same geometry is used for both release and impulse functions, then the structure is symmetric and simple, but the geometry cannot be optimized for both functions simultaneously
Solution Approach 1:
The patent employs different cam profiles for the release and impulse functions. The first cam portion is optimized for the release function with one geometric profile, while the second cam portion is optimized for the impulse function with a different profile, allowing each function to operate at optimal efficiency
Solution Approach 2:
The escapement mechanism uses asymmetric cam geometries where the engagement surfaces for release and impulse are deliberately made different. This asymmetry allows optimization of each function's performance characteristics, improving overall power efficiency despite increased geometric complexity
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 design significantly reduces wear and energy losses, enhancing the efficiency and power conservation of the escapement mechanism while maintaining accuracy and reliability over time.
Implementation Method 1
The optimization of the geometry of the contact surfaces between the pin and the fork aims in particular to reduce friction in order to reduce the wear of the parts, or even to reduce the energy losses to increase the efficiency of the escapement
Implementation Method 2
It is sought to have a rolling movement without slipping between the parts of the peg and the fork coming into contact
Data Source
Figure 1
Figure 2(a)~3
Figure 4~5(b)
AI summary
An escapement mechanism (3) for a watch movement comprising an anchor (7) with a fork (13), and a balance wheel assembly (4) with a pin coupled to a balance (2). The fork comprises a first lug (19) and a second lug (21). The pin comprises a first cam portion (12) configured to engage an engagement surface (23) of the first lug, and a second cam portion (14) configured to engage an engagement surface (25) of the second lug. The portion of the engagement surfaces in contact with the cam portions comprises a non-planar geometric profile.