Abstract: A damping apparatus comprises an actuator consisting of an oscillating element for transforming an electric oscillation into a mechanical oscillation and an amplifying mechanism for amplifying the resulting mechanical oscillation as interposed between two structures at least one of which is a source of vibration so that the mechanical oscillation output of the actuator is superimposed on the vibration to be controlled. As such, it may include a sensor disposed in the path of propagation of the vibration to be attenuated and a control device which, in response to the output signal from said sensor, applies an electric oscillation associated with the vibration to be attenuated. A sensor transforms the mechanical vibration to be attenuated into an electric oscillation and, in response to this output electric oscillation, the control device applies an electric signal associated with the vibration to be attenuated to the oscillating element.

Abstract: The vibration isolation device of this invention is to be interposed between a vibrating body and a vibrated body, characterized in that at least one of the vibrating body and the vibrated body is fastened to the surface of a vibration isolating device which is abutted against it through a piezoelectric insert interposed constant ?K! which is represented by a particular formula or a fastener which is capable of piezoelectric displacement.

Abstract: An apparatus which is responsive to fluid pressure for detecting and indicating visually and accoustically the variation of pressure conditions such as the underinflation of vehicle tires. The apparatus comprises pressure sensors, annular conductive members, at least a pair of confronting heads, response means and indicating means. When the tire air pressure is normal, since the impedance value of the conductive members does not vary, the indicating device is not actuated. However, if the air pressure within even one of the tires becomes abnormal, the apparatus performs as designed and a signal emitted by the indicating device informs the driver of the abnormality.