| 摘要 |
PROBLEM TO BE SOLVED: To prevent the propagation of vibration to a placing object placed on an upper base regardless of the magnitude of vibration by a vibration resistant mechanism to absorb vibration so as to prevent propagation of vibration of a lower base to the upper base and a seismic isolation mechanism to displaceably support the lower base. SOLUTION: A vibration isolation device 1 comprises an upper base 3 on which a placing object 2 is installed; a lower base 4 positioned facing a position below the upper base 3; a vibration resistant mechanism 5 located between the upper and lower bases 3 and 4; and a seismic isolation mechanism 7 located between the lower base 4 and a foundation 6. The vibration resistant mechanism 5 consists of elastic substances 8a and 8b, such as rubber, having elasticity and the seismic isolation mechanism 7 comprises stays 10a and 10b slidably supporting the lower base 4 erected from the foundation 6; coil spring 11a and 11b to energize the lower base 4 to an origin position; and lock mechanisms 12a and 12b to lock the lower base 4 to the origin position. A control circuit 21 releases a lock by the lock mechanisms 12a and 12b and effects switching from vibration resistant operation to seismic isolation operation when acceleration detected by an acceleration sensor 9 exceeds a limit value. |
