The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 02, 1999
Filed:
Jun. 23, 1997
Takahide Haga, Kawasaki, JP;
Katsuhide Watanabe, Fujisawa, JP;
Ebara Corporation, Tokyo, JP;
Abstract
A compact vibration cancellation apparatus based on a combination of air springs and electromagnetic actuators with smaller power capacity enables an anti-vibration table to be maintained in a level position even when the center of gravity of the anti-vibration table moves a large distance because of a movement of objective equipment on the table. The vibration cancellation apparatus is operable for isolating floor vibration or for canceling vibration of the objective equipment on the anti-vibration table. The apparatus includes displacement sensors, acceleration sensors, a levitation position control device, a vibration canceling control device, and air spring actuators for supporting four corners of the anti-vibration table by air pressure. The air pressure in each air spring actuator is controlled in response to a change of load which corresponds to a movement of the center of gravity caused by movement of the objective equipment on the anti-vibration table.