Escapement Assembly Anti-Overbanking Wall Design
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Solution Overview
Problem
Conventional escapements with guard pins are prone to malfunction and damage due to the risk of the roller pin penetrating into the notch during changes in rotation direction, leading to sudden stopping of the timepiece movement.
Innovation Solution
The design features pallets, a roller, and a pin configured such that each horn of the pallet fork can only penetrate into the roller's notch when the pin is partially situated in the pallet fork, ensuring reliable operation by maintaining the distance between the pin and the anti-overbanking wall greater than the notch's junction, and incorporating specific geometrical characteristics to prevent penetration in knocking situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the guard pin is removed to reduce overall thickness, then the escapement size is reduced, but the reliability deteriorates due to risk of horn penetration into the notch during knocking
Solution Approach 1:
The anti-overbanking wall acts as an intermediary protective structure between the horn and the notch. It prevents the horn from penetrating into the notch during knocking situations by providing a physical barrier that the horn contacts before it could reach the notch, thus eliminating the reliability issue while maintaining the reduced thickness design
Solution Approach 2:
The geometric parameters of the horn and anti-overbanking wall are specifically designed and constrained. The horn's length and the anti-overbanking wall's position are dimensioned so that the horn can only reach the notch when the pin is properly positioned in the pallet fork entry, not when it is in knocking positions. This parameter control ensures reliability without requiring a guard pin
2Ease of operation
If the horn is allowed to penetrate into the notch for normal operation, then the pallet fork can pivot correctly, but the harmful effect occurs during knocking when sudden stopping and damage may result
Solution Approach 1:
The anti-overbanking wall provides localized protection at the specific location where the horn could penetrate the notch. This localized structural feature allows the horn to penetrate the notch during normal operation when needed for pallet fork pivoting, while preventing penetration during knocking situations where the horn would contact the anti-overbanking wall first
Solution Approach 2:
The anti-overbanking wall provides preliminary protection by being positioned to intercept the horn before it can reach the notch during knocking. This preliminary anti-action prevents the harmful penetration from occurring in the first place, allowing the design to permit penetration during normal operation without risk during knocking
Data Source
AI summary
An escapement is disclosed which includes pallets, a roller and a pin fastened to the roller, intended to cooperate with one another. The pallets have no guard pin and include a pallet fork intended to cooperate with the pin and the roller and including first and second horns delimiting an entry of the pallet fork. The roller has an anti-overbanking wall in which a notch is formed, in a region adjacent to the pin. The pallets, the roller and the pin are conformed and dimensioned in such a manner that, in the service position, the anti-overbanking wall is able to define an abutment for the first and second horns, and each of the horns is able to penetrate to the interior of the notch exclusively when the pin is at least partly situated in the entry of the pallet fork.