Abstract: A vibration damper, e.g. for damping retraction or extension springing forces on motor vehicles, includes a pressure medium cylinder in which a piston with a piston rod is axially slidably arranged. The piston divides the cylinder into first and second chambers which contain an electrorheological or magnetorheological fluid as a pressure medium. The two chambers are connected with one another through a throttle gap with at least one field generating element arranged adjacent thereto. The length of the throttle gap is divided by a gap intersection point into a first throttle gap section connected with the first chamber, and a second throttle gap section connected with the second chamber. A non-return check valve is arranged in a bypass gap connected parallel to the first throttle gap section between the gap intersection point and the first chamber.

Abstract: The invention relates to a vibration damper, especially for damping retraction or extension springing forces on motor vehicles, which includes a pressure medium cylinder (2), in which a piston (3) with a piston rod (3) is axially slidably arranged. The piston divides the pressure medium cylinder (2) into a retraction chamber (5) and an extension chamber (6), in which an electrorheological or magnetorheological fluid is contained as a pressure medium. The retraction (5) and extension chambers (6) are connected with one another at least by a throttle gap (7), in the region of which at least one field force generating element (17) is arranged. At least one further non-return check valve (14) is arranged in a further gap (13) between the pressure medium chambers (5, 6). The invention is characterized in that the length of the throttle gap (7) is divided by a gap intersection or gating point (10) into a first throttle gap section (11) and a second throttle gap section (12).

Abstract: An apparatus for determining the unbalance of a rotational body includes a central mounting plate with a mounting fixture on which the rotational body is received, an outer frame, and a plurality of supporting webs that connect the mounting plate to the frame. The webs are configured and arranged so that the mounting plate can pivotally vibrate about a pivot axis, and translationally vibrate in the plane of the mounting plate. A first vibration transducer measures the pivoting vibration and a second vibration transducer measures the translational vibration. The pivot axis remains in the central plane of the mounting plate which coincides with the effective plane of the translational vibration measuring transducer.

Abstract: A support structure with a vibration damper permits rotatably holding a rotatable body to be balanced, without applying undesirable constraining forces to the rotor or wheel. The vibration damper is an elastomeric element, for example a metal rubber composite element, inserted between the rotatable body and a support which itself is separately mounted by spring elastic mountings in a machine frame. The vibration damping element is effective between the rotatable body and the support if the element is inserted between a bearing and the rotatable body or if the element is inserted between the bearing and the support.