Publications related to Marine chronometer

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

Theory and design of spherical oscillator mechanisms

Simon Nessim Henein, Roland Andreas Bitterli, Ilan Vardi, Lennart Rubbert, Mohammad Hussein Kahrobaiyan, Nicolas Ferrier, Billy Nussbaumer

In previous work, we showed that two degree of freedom oscillators can be advantageously applied to horological time bases since they can be used to eliminate the escapement mechanism. We subsequently examined planar two degree of freedom oscillators based ...

2018

Escapement-Based Movements as Positioning Mechanisms: Design and Modelling

Romain David Besuchet

This work has been triggered by an industrial project targeting the design of a mechatronic injector for the medical field. Injections are usually performed using a syringe, a quite clumsy tool that transforms the injection task in a positioning one. The q ...

EPFL2016

Xy isotropic harmonic oscillator and associated time base without escapement or with simplified escapement

Simon Nessim Henein, Ilan Vardi, Lennart Rubbert

The mechanical isotropic harmonic oscillator comprises at least a two degree of freedom linkage supporting an orbiting mass with respect to a fixed base with springs having isotropic and linear restoring force properties. The oscillator may be used in a ti ...

2015

Un nouveau régulateur mécanique pour une réserve de marche exceptionnelle

Simon Nessim Henein, Philippe Schwab

«Voyager, c’est bien utile, ça fait travailler l’imagination» (Céline). C’est à l’occasion d’un voyage en train entre Neuchâtel et Genève que Pierre Genequand, alors ingénieur au CSEM, eut l’idée d’associer les avantages des structures flexibles et les car ...

2014

Analyse, synthèse et création d'échappements horlogers par la théorie des engrenages

Olivier Laesser

In principle, knowledge of watch and clock escapements is acquired through the study of the geometry and operation of numerous realizations, studied patiently one after the other. Knowing the classics, one can hope to construct a new realizations by borrow ...

EPFL2014

Analyse et mise en oeuvre d'un moteur électromagnétique microfabriqué

Sebastiano Merzaghi

Until now, the preferred solution for MEMS (Micro Electro Mechanical Systems) actuation is the electrostatic one. The main reason is that this kind of actuators can be easily manufactured following the microfabrication rules, as their geometry perfectly fi ...

EPFL2010

Conception et optimisation multicritère des échappements libres pour montres-bracelets mécaniques

Thierry Conus

The watchmaking crisis of the nineteen-seventies in effect marked an interruption of scientific research into the working of mechanical watches. For the past few years, a revival of interest in these timepieces has given industrialists the financial resour ...

EPFL2007