| 摘要 |
PURPOSE:To have a high precision level adjustment regardless of the response performance of valves, by improving the work control of intake and exhaust valves in a pneumatic spring device to bear an anti-vibratory table. CONSTITUTION:A pneumatic spring device 32 to support the table 31 is designed to provide possibility of level adjustment by actuating the intake 37 exhaust 36 valves by means of comparison of the signal from sensor 34 sent to a control device 35 with the reference value. It takes three seconds after the intake 37 and exhaust 36 valves are actuated till the air in the pneumatic spring device moves thereby and the table 31 is actually moved vertically, so that the table 31 works simply as indicated by the Curve 131 if these valves 36, 37 are put in operation either simultaneously or at a certain interval, after the intake valve 37 and 1 or exhaust valve 36 are actuated and before the table 31 commences the vertical motion actually. Thus a fine adjustment becomes possible, that will never be obtained from the function of either of the valves. |
