Control type liquid seal vibration control device

A control type liquid-sealed vibration-proof device which comprises a vibration-insulating base made of a rubber elastomer, a first attachment fitting connected to the vibration-insulating base on the vertically one side thereof a cylindrical main body fitting connected to the vibration-insulating base on the other side thereof a diaphragm attached to the main body fitting so as to oppose to the vibration-insulating base, a partition division partitioning an interior enclosed between the vibration-insulating base and the diaphragm into a main liquid chamber on the vibration-insulating base side and a first subsidiary chamber on the diaphragm side and including a membrane and a partition proper, a switchover chamber surrounded by the partition proper and the membrane, capable of switching over the introduction of the atmospheric pressure and a negative pressure, a second subsidiary liquid chamber spaced apart from the switchover chamber through the membrane, and a first orifice and a second orifice through which to put the main liquid chamber into communication with the first and the second subsidiary liquid chambers, respectively,

• which device is characterized in that either of the membrane and a wall surface of the switchover chamber opposed thereto is provided with differentiated steps so that by the introduction of a negative pressure into the switchover chamber the membrane may come, stepwise from its outer circumference in order, into contact with the wall surface to be put under constraint.