To solve a problem, for example, in which holding a movable mass becomes difficult because the spring characteristics of a rubber constituting a basis are set low in order to set the characteristic value at a low value. In a first dynamic vibration absorber including a movable mass that is coupled to a vibration damping target member via an MRE as a first elastic member having elastic characteristics variable with a magnetic field, and being capable of varying a vibration characteristic value of the movable mass by controlling the magnetic field, the dynamic vibration absorber has a second elastic member different from the MRE, and the vibration damping target member and the movable mass are elastically-coupled to each other via the second elastic member.

A mechanical system, such as cryogenic refrigerator system, is described. The system comprises two or more axial moving elements generating two or more cyclic forces along parallel axes and a vibration attenuation unit. The cyclic forces are provided with common frequency and certain phase difference between them. The vibration attenuation unit is configured for attenuating vibrations corresponding to two or more modes of vibrations characterized by a frequency corresponding to operation frequency of said two or more cyclic forces.

A rotorcraft having an antivibration system, the antivibration system being arranged at the interface between a fuselage of the rotorcraft and a casing of a main power transmission gearbox, or “MGB”, in order to transmit rotary motion generated by an engine of the rotorcraft to a main rotor providing the rotorcraft at least with lift, and possibly also propulsion, the antivibration system including calculation means for analyzing as a function of time the dynamic excitation and the resulting vibration transmitted to the fuselage of the rotorcraft.

An example cantilever assembly includes a cantilever including an anchor configured to be coupled to a support, a tip, and an arm positioned between the anchor and the tip, a hollow conductive tube positioned at the tip of the cantilever, and a magnet suspended inside the hollow conductive tube with a first spring and a second spring. The first spring and the second spring are positioned at a first end and a second end of the hollow conductive tube respectively, and the magnet is positioned between the first spring and the second spring. The magnet is configured to move coaxially inside the hollow conductive tube as permitted by the first spring and the second spring, and the magnet suspended inside the hollow conductive tube operates as a tuned mass damper (TMD) to limit a resonant response of the cantilever assembly.

A steering wheel damper may include a plate fastened to a hub of a steering wheel; one or more posts each having one side fixed to a surface of the plate and the other side extending perpendicular to the surface of the plate; a mass body spaced from the plate, attached to the other side of the post, supported by the posts, and having upper and lower portions configured as magnet bodies having different polarities; and an electromagnet made by winding a coil around a core fixed to the surface of the plate.

A vibration isolation device for optimally decoupling shear forces that are orthogonal to the principal direction of isolation from microvibrations. A pivoting load support element is free to pivot about a pivot point in response to shear forces, with optimal isolation from coupling to the principal direction of vibration isolation. A friction free bearing for small motion is provided to respond to the forces perpendicular to the principal direction of vibration isolation. An internal load support plate associated with the pivoting element is supported by equalizing springs and is damped by an active actuator driven according to a sensor on the internal load support plate. Adjustment points, such as screws, adjust the pivoting element with respect to the fixed pivot point.

A method, system and devices to selectively control modal vibrations in an elastic panel with a number of force actuators distributed throughout the surface of the elastic panel to excite/depress the response of one or more vibrational resonant modes included in a prescribed subset. The force actuators are disposed such that prescribed modal excitation/depression may be realized when the actuators are driven by a common source signal.

A new type of independently damping pendulum suspension for pendulum dampers for use in tall slender constructions and technical installations, more particularly used in wind turbines. A Cardan joint is equipped with damping elements and mounted at the other end opposite the pendulum mass. The Cardan joint is able, despite the small motions, to sufficiently damp the oscillations of the pendulum produced by disturbing frequencies.

The present invention relates to improvements in or relating to tremor stabilisation apparatus and methods, in particular to gyroscopic devices for use in controlling tremors of parts of the body and for reducing effects of tremors on the human body. The apparatus includes a wearable element and at least one gyroscopic device mounted or mountable to the wearable element, the gyroscopic device including a gyroscope and a gyroscope housing. The at least one gyroscopic device may be mounted within the housing such that the gyroscope may precess with respect to the housing. The mount may include a hinge to which the gyroscope is mounted and a hinge plate or hinge mount to which the hinge is mounted for rotation with respect to the gyroscope housing, such as a turntable mounted to the gyroscope housing. The gyroscopic devices may include a control arrangement to control the precession of the gyroscope.

An active vibration damper includes a lower outer wall for placement on a floor, and front and rear outer walls, with the front and/or rear outer wall including first and second receptacles in an outer side thereof. The first receptacle receives a permanent magnet and is pot-shaped to maintain a closed configuration of the front and/or rear outer wall. A primary part of an electrical linear actuator is fixed at least on an inside of the lower outer wall, and a secondary part is arranged above the primary part and acted upon by the primary part. Retaining elements fixed to an inside of the upper outer wall movably hold the secondary part for displacement in a substantially linear manner in a left-right direction when the primary part is correspondingly impinged on. A magnetic back iron yoke is received in the second receptacle at the height of the secondary part.