Abstract: A boring bar with electrodynamic actuators is for counteracting vibrations and machine tool provided with such a bar. The boring bar includes a wall, an internal recess and a longitudinal axis. The boring bar has a first electrodynamic actuator with coil windings associated with a moving mass and a spring assembly that are arranged to define a first actuation direction perpendicular to the longitudinal axis of the boring bar. A second electrodynamic actuator has coil windings associated with a moving mass and a spring assembly that are arranged to define a second actuation direction perpendicular to both the first actuation direction and the longitudinal axis of the boring bar. The actuators allow counteraction of the vibrations in the directions perpendicular to the longitudinal axis of the bar. The longitudinal axis also defines the boring direction.

Abstract: The invention relates to an unbalance dynamic load generator comprising at least one pair of eccentric rotating masses (M) which are symmetric with respect to a plane and whose motion is controlled by at least one control signal generated by a control module as a function of a preset signal (Fd(t)) having a given frequency. It is characterized in that, for at least one of the masses, it comprises a reference angular position sensor (C) delivering a position signal (SP) representing the passing of the said rotating mass (M) through a reference angular position and a control circuit comprising a calculation circuit (DSP) for calculating the periodicity of the rotation of the said mass from the successive position signals delivered by the position sensor (C) and for generating the said control signal (CS) as a function of the difference between the measured periodicity and the periodicity of the preset signal.

Abstract: The invention provides a dynamic beater comprising a spring-mass unit, said unit having a mass M and a stiffness K actuated by a drive motor and presenting a device for coupling to a host structure for damping, the beater presenting a first acceleration sensor secured to said mass and delivering a first signal s1, and a second acceleration sensor for mounting on the host structure and delivering a second signal s2, and also having a power amplifier supplying an output signal for controlling the drive motor in response to an input signal E which is a function of a difference between the signals from the first and second acceleration sensors after passing at least one of said signals through at least one lowpass filter and/or phase delay type filter.

Abstract: The invention relates to a damper device for damping vibration, the device comprising an energy converter device mounted on a baseplate for fixing to a structure, the energy converter device presenting a moving portion suspended by at least one spring. The moving portion presents at least one flat centering spring extending between an inside region having a first diameter and an outside region having a second diameter, said centering spring presenting at least two cutouts, each being in the form of a branch having at least one segment turning its concave side towards the outside of the spring.

Abstract: The invention provides a dynamic beater comprising a spring-mass unit, said unit having a mass M and a stiffness K actuated by a drive motor and presenting a device for coupling to a host structure for damping, the beater presenting a first acceleration sensor secured to said mass and delivering a first signal s1, and a second acceleration sensor for mounting on the host structure and delivering a second signal s2, and also having a power amplifier supplying an output signal for controlling the drive motor in response to an input signal E which is a function of a difference between the signals from the first and second acceleration sensors after passing at least one of said signals through at least one lowpass filter and/or phase delay type filter.

Abstract: The invention relates to an unbalance dynamic load generator comprising at least one pair of eccentric rotating masses (M) which are symmetric with respect to a plane and whose motion is controlled by at least one control signal generated by a control module as a function of a preset signal (Fd(t)) having a given frequency. It is characterized in that, for at least one of the masses, it comprises a reference angular position sensor (C) delivering a position signal (SP) representing the passing of the said rotating mass (M) through a reference angular position and a control circuit comprising a calculation circuit (DSP) for calculating the periodicity of the rotation of the said mass from the successive position signals delivered by the position sensor (C) and for generating the said control signal (CS) as a function of the difference between the measured periodicity and the periodicity of the preset signal.

Abstract: The invention relates to a damper device for damping vibration, the device comprising an energy converter device mounted on a baseplate for fixing to a structure, the energy converter device presenting a moving portion suspended by at least one spring. The moving portion presents at least one flat centering spring extending between an inside region having a first diameter and an outside region having a second diameter, said centering spring presenting at least two cutouts, each being in the form of a branch having at least one segment turning its concave side towards the outside of the spring.

Abstract: The invention relates to a damper device for damping vibration comprising a converter device for converting mechanical energy into electrical energy that is mounted on a baseplate for fixing to a structure for damping. Said converter device comprises an electrodynamic motor having a coil mechanically connected to the baseplate and a magnetic circuit suspended by at least one spring, the coil is coupled to an electrical load presenting a resistive component, and it presents a control device for causing the resistance of said resistive component to vary with at least two values.

Abstract: The invention relates to a resonant device comprising a mass/spring system composed of a main mass comprising at least one main mass element, and of at least one spring element (3). The device is one which comprises at least one additional mass (10) comprising at least one additional mass element (102) and a coupling device (204) able to couple the additional mass (10) to the main mass (1) and to decouple it therefrom, so as to modify the tuning frequency of the device.

Abstract: The invention relates to a generator of dynamic loads comprising a main mass/spring system composed of a main mass comprising at least one main mass element of mass M2 and of at least one main spring element of stiffness K2. The device is one which comprises an additional mass/spring system, which is coupled to the main mass/spring system and which is composed of an additional mass of mass m3 and of at least one additional spring element of stiffness K3, the assembly exhibiting a first and a second resonant frequency f0 and f2 respectively, and an anti-resonant frequency f1, with f0<f1<f2.