This thesis focuses on the development of a short-term, operationally stable finite element-based simulation of a mechanical watch lever escapement. This was accomplished in four steps: by choosing a reference escapement based on the needs of the study, by executing a reverse engineering methodology to create a lever escapement in computer-aided design (CAD) software, by capturing experimental data from the reference escapement via custom- built apparatus and then reconciling this data with an analytical model, and by using the knowledge gained from these efforts to develop an implicit dynamic simulation of a lever escapement that aimed to achieve performance metrics defined by watchmaking sources.
The final version of the simulated lever escapement was able to meet two of the three performance goals defined for the study. The simulation met the primary performance goal by achieving stable operation for two seconds. During this window of stability, the simulated lever escapement met the secondary performance goal of the study by achieving timing performance metrics defined by watchmaking sources. Unfortunately, the tertiary performance goal was not met as the balance amplitude of the final simulation was outside of the target range by 5.23% when compared against the lower bound. Although the balance amplitude error of the simulated escapement would be indicative of a mechanism that needs servicing, its performance during the stability period was assessed to be representative of a functional lever escapement and therefore, its dynamics and sensitivities were explored and presented. / Master of Science / Mechanical watches rely on physics to keep accurate time. The time regulation mechanism within a mechanical watch is called an escapement, and the most widely used escapement design adopted by watchmakers is the lever escapement. While prior attempts have been made to simulate the physics that these mechanisms use to keep accurate time, achieving stable operating performance in a complete lever escapement simulation remains elusive in published studies. The examination of a stable, simulated lever escapement could reveal new insights into these mechanisms by reducing the impact of transient phenomena.
This thesis focuses on the development of a short-term, operationally stable simulation of a lever escapement mechanism. This was achieved by developing a model of a real-world lever escapement, by capturing experimental data to improve the model, and then by applying the knowledge gained from these efforts to create a dynamic simulation in Abaqus/CAE. The final simulation was able to meet two of the three performance goals defined for the study, which proved that it is possible to create a simulation of a lever escapement. Furthermore, the study revealed unexpected phenomena that may be present in real-world lever escapements and may affect their performance.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/112753 |
| Date | 30 November 2022 |
| Creators | Naperkoski, Brian Michael |
| Contributors | Mechanical Engineering, West, Robert L., Philen, Michael Keith, Bohn, Jan Helge |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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