Publications by Lennart Rubbert

Flexible surgical device with controllable stiffness

The invention relates to a surgical device (10), comprising a tubular outer shaft (12,) and an inner element (14) having an elongated shape, the outer shaft comprising a distal (30a) and a proximal (30b) outer hinges, the inner element comprising an inner ...

2022

Design of a compliant load cell with adjustable stiffness

Charles Baur, Lennart Rubbert, Michal Stanislaw Smreczak

Manipulation at the sub-micron scale often requires force-sensing capabilities of milli-to nanonewton forces. This article presents a novel design of a compliant load cell with mechanically adjustable stiffness. The system enables adapting force sensitivit ...

2021

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

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

Higher-order continuation method for the rigid-body kinematic design of compliant mechanisms

Simon Nessim Henein, Lennart Rubbert

Compliant mechanisms are of great interest in precision engineering. In this paper we propose a higher order continuation method to help their rigid-body kinematic design. The method helps to investigate the choice of a mechanism configuration through the ...

2017

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

The mechanical isotropic harmonic oscillator comprises at least a two degrees of freedom linkage supporting an orbiting mass with respect to a fixed base with springs having isotropic and linear restoring force properties wherein the mass has a tilting mot ...

2015

Isotropic springs based on parallel flexure stages

Simon Nessim Henein, Nicolas Ferrier, Roland Andreas Bitterli, Sebastian Krzysztof Fifanski, Ilan Vardi, Lennart Rubbert

We define isotropic springs to be central springs having the same restoring force in all directions. In previous work, we showed that isotropic springs can be advantageously applied to horological time bases since they can be used to eliminate the escapeme ...

2015

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