Publications de Mohammad Hussein Kahrobaiyan

Mechanical oscillator with tunable isochronism defect

Simon Nessim Henein, Mohammad Hussein Kahrobaiyan, Mohamed Gamal Abdelrahman Ahmed Zanaty

Mechanical oscillator (1) for a timepiece comprising an inertial mass (3) arranged to oscillate about a neutral position under the effect of a restoring force provided by at least one elastic element (5),characterised in that said mechanical oscillator (1) ...

2020

Device for measuring a force exerted on an object

Simon Nessim Henein, Charles Baur, Mohammad Hussein Kahrobaiyan, Mohamed Gamal Abdelrahman Ahmed Zanaty

The present invention relates to a device for measuring a contact force exerted by an object on a probe comprising a lever and said probe for contacting the object. The lever is pivotably coupled to a body by coupling means. The device comprising a fixed f ...

2020

Two degree of freedom oscillator system

Simon Nessim Henein, Billy Nussbaumer, Mohammad Hussein Kahrobaiyan

Oscillator system (1) comprising:- a substantially planar frame (3);- a first sub-oscillator (5), a second sub-oscillator (7), a third sub-oscillator (9), and a fourth sub-oscillator (11), each sub-oscillator (5, 7, 9, 11) comprising a substantially rigid ...

2020

Flexure Pivot Oscillator With Intrinsically Tuned Isochronism

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

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

Horological oscillator

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

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

Two degree of freedom mechanical oscillator

Simon Nessim Henein, Mohammad Hussein Kahrobaiyan, Ilan Vardi

Mechanical oscillator (10) comprising an inertial body (101) joined to a support (100) by means of an elastic system (102, 103, 104, 105, 106, 107) arranged to provide the inertial body (101) with substantially no degrees of freedom in translation and with ...

2018

Flexure-Pivot Oscillator Restoring Torque Nonlinearity and Isochronism Defect

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

Flexure pivot based oscillators can advantageously replace the hairspring and balance wheel, the time base used in mechanical watches, by drastically reducing friction. However, flexure pivots have drawbacks including gravity sensitivity and restoring torq ...

AMER SOC MECHANICAL ENGINEERS2018

Mechanical oscillator

Simon Nessim Henein, Mohammad Hussein Kahrobaiyan, Ilan Vardi

wherein k1, k3, k5 . . . are constants and θ is an angle of inclination of said third axis (x, P) of said inertial body with respect to a direction of said third axis (xr) when said inertial body is in said resting position. ...

2018

Theory and design of spherical oscillator mechanisms

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

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

Gravity-Insensitive Flexure Pivot Oscillators

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

Classical mechanical watch plain bearing pivots have frictional losses limiting the quality factor of the hairspring-balance wheel oscillator. Replacement by flexure pivots leads to a drastic reduction in friction and an order of magnitude increase in qual ...

2018

An Analytical Model for Beam Flexure Modules Based on Timoshenko Beam Theory

Simon Nessim Henein, Mohammad Hussein Kahrobaiyan, Mohamed Gamal Abdelrahman Ahmed Zanaty

Short beams are the key building blocks in many compliant mechanisms. Hence, deriving a simple yet accurate model of their elastokinematics is an important issue. Since the Euler-Bernoulli beam theory fails to accurately model these beams, we use the Timos ...

2017

Investigating The Size-Dependent Static And Dynamic Behavior Of Circular Micro-Plates Subjected To Capillary Force

Simon Nessim Henein, Mohammad Hussein Kahrobaiyan, Ilan Vardi

The size-dependent static deflection, pull-in instability and resonant frequency of a circular microplate under capillary force have been studied using modified couple stress elasticity theory. SiZe-dependency is a phenomenon in which the normalized quanti ...

Amer Soc Mechanical Engineers2016

Investigation of Size-Dependency in Free-Vibration of Micro-Resonators Based on the Strain Gradient Theory

Mohammad Hussein Kahrobaiyan

This paper investigates the vibration behavior of micro-resonators based on the strain gradient theory, a non-classical continuum theory capable of capturing the size effect appearing in micro-scale structures. The micro-resonator is modeled as a clamped-c ...

FapUNIFESP (SciELO)2016