Publications associées à Chronomètre de marine

Shaking force balancing of a 2-DOF isotropic horological oscillator

Simon Nessim Henein, Hubert Pierre-Marie Benoît Schneegans, Etienne Frédéric Gabriel Thalmann

Despite centuries of research and significant advances, the escapement mechanism used to count and maintain oscillations of mechanical time bases remains a complex mechanism and a major source of energy losses. We showed in previous work that, instead of t ...

2021

Rocker oscillator time bases

Simon Nessim Henein, Ilan Vardi

Since the invention of the pendulum clock by Christiaan Huygens in 1657, precision timekeepers have been regulated by oscillators. Although the pendulum is not an isochronous oscillator, its introduction as a time basis for clock regulation led to a signif ...

2021

Direct time-of-flight SPAD image sensors for light detection and ranging

Preethi Padmanabhan

Depth sensing is an increasingly important feature in many applications of consumer, automotive, augmented/virtual reality (AR-VR), space and bio-medical imaging. Long range, high depth resolution, high spatial resolution, and high frame rates are often co ...

EPFL2021

Flexure Pivot Oscillator With Intrinsically Tuned Isochronism

Simon Nessim Henein, Ilan Vardi, Etienne Frédéric Gabriel Thalmann, Mohammad Hussein Kahrobaiyan

The most important property for accurate mechanical time bases is isochronism: the independence of period from oscillation amplitude. This paper develops a new concept in isochronism adjustment for flexure-based watch oscillators. Flexure pivot oscillators ...

2020

Flexure Pivot Oscillators for Mechanical Watches

Etienne Frédéric Gabriel Thalmann

It appears that the concerted efforts of the watchmaking industry are leading towards a limit in mechanical watch accuracy. The general consensus in horology is that the time base's quality factor, a dimensionless number that characterizes the oscillator d ...

EPFL2020

Automatically Starting and Secured Detent Escapement for a Timepiece

Simon Nessim Henein, Ilan Vardi

A horological detent escapement for a horological movement arranged to transmit a torque from said horological movement to an oscillating regulating organ of said horological movement, the regulating organ comprising a first mobile body and the escapement ...

2019

Conceptual design of a rotational mechanical time base with varying inertia

Simon Nessim Henein, Etienne Frédéric Gabriel Thalmann

Flexure pivot oscillators have the potential to advantageously replace the traditional balance wheel-spiral spring oscillator used in mechanical watches due to their significantly lower friction. However, they have inherent nonlinear elastic properties tha ...

2019

Horological oscillator

Simon Nessim Henein, Ilan Vardi, Etienne Frédéric Gabriel Thalmann, Mohammad Hussein Kahrobaiyan, Billy Nussbaumer

Horological oscillator comprising: - a first inertial body (141; 151; 1305; 1405; 1505; 301; 311; 314; 41; 51; 507; 529; 544; 541; 901; 903) arranged to rotate with respect to a first axis; - a second inertial body (143; 153; 1306; 1406; 1506; 302; 313; 31 ...

2019

General 2 degree of freedom isotropic harmonic oscillator and associated time base without escapement or with simplified escapement

Simon Nessim Henein, Ilan Vardi, Lennart Rubbert

A mechanical isotropic harmonic oscillator including a frame, a mass configured to oscillate, and three flexure rods, each flexure rod connecting the mass to the frame. ...

2019

Programmable Multistable Mechanisms: Design, modeling, characterization and applications

Mohamed Gamal Abdelrahman Ahmed Zanaty

Multistable Mechanisms are mechanical devices having more than one stable state. Since these mechanisms can maintain different deformations with zero force, they are advantageous for low power environments such as wristwatches and medical devices. In this ...

EPFL2018