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. 05, 2002
Filed:
Jul. 14, 2000
Other;
Abstract
An electric discharge machining apparatus comprises a quill movable in the vertical direction, at least one set of linear motor movers attached to the quill, symmetrically about a center axis of the quill, and a single set of linear motor stators facing the set of movers. An electrode mounting device ( ) for holding a tool electrode ( ) is attached to a lower end of the quill, coaxially with the quill. Preferably, the set of movers includes magnetic plates ( ) attached to the quill and a row of permanent magnets ( ) arranged on the magnetic plates, and the set of stators includes a yoke ( ) and a coil ( ) wound around the yoke. The quill has a hole ( ) in its center extending in the vertical direction, and an air cylinder ( ) providing counter balance for the load of the quill is preferably disposed in this hole. The quill has a density of 4g/cm or less, and is made of, for example, silicon nitride (Si N ) ceramics or a composite material of a light metal and at least 40% by volume of ceramics.