Escapement Torque Transmission Optimization
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Solution Overview
Problem
Traditional escapements in watchmaking experience variations in torque transmission due to planar impulsion surfaces, leading to performance compromises and pallet lifting-off during transitions.
Innovation Solution
The escapement features impulsion surfaces on both pallets and teeth with specific geometric configurations, where the tangent of the impulsion surface intersects the center-to-center line at optimized angles, ensuring constant torque transmission and preventing pallet lifting-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If planar impulsion surfaces are used on pallets, then manufacturing is simplified, but torque transmission varies throughout the impulsion phase
Solution Approach 1:
The patent applies curvature to the impulsion surfaces of both the pallets and escapement wheel teeth, replacing traditional planar surfaces with specifically curved profiles. The curvature is designed so that the tangent of the impulsion surface intersects the center-to-center line between the escapement wheel and anchor at optimized angles, ensuring constant torque transmission throughout the impulsion phase while remaining manufacturable
2Ease of manufacture
If planar impulsion surfaces are used on pallets, then manufacturing is easier, but pallet lifting-off occurs during transitions
Solution Approach 1:
The curved impulsion surfaces on both pallets and teeth create continuous contact during transitions by optimizing the angle of intersection between the tangent of the impulsion surface and the center-to-center line. This curvature prevents the pallet from lifting off the tooth during the transition from impulsion phase on the pallet to impulsion phase on the tooth
3Ease of manufacture
If conventional radius of curvature is used on convex part of pallet, then manufacturing is simpler, but torque transmission varies significantly (25-35% variation)
Solution Approach 1:
The patent optimizes the radius of curvature parameters of the impulsion surfaces, specifically designing the convex part at the start of the impulsion surface with a specifically optimized radius rather than conventional radii. This parameter optimization, combined with the overall curved profile, ensures that the derivative of the torque ratio remains constant, eliminating the 25-35% torque variation present in conventional designs
Data Source
AI summary
An escapement for a timepiece, comprising: —an escapement wheel pivotally mounted around a corresponding axis of rotation and intended to be driven by a drive source, said escapement wheel comprising a plurality of teeth; —a pallet fork pivotably mounted around a corresponding axis of rotation, said pallet fork comprising an entry pallet and an exit pallet, each pallet comprising a rest face arranged to block the escapement wheel, as well as a pulse face arranged to interact with the escapement wheel in order to transmit the pulses received from the latter to a regulating member arranged to perform oscillations, said pallet fork being arranged to free the escapement wheel periodically under the control of the regulating member, characterized in that at least one of the pulse faces is shaped in such a way that, on at least one portion of the pulse face, and considered at each point of contact (C′) between the escapement wheel and the pulse face, the tangent of the pulse face intersects the center-to-center distance between the escapement wheel and the pallet fork according to an angle (αorientation) that observes a particular relation.