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:
Sep. 24, 1996
Filed:
Jul. 29, 1994
Yoshiharu Seto, La Mirada, CA (US);
Xilinx, Inc., San Jose, CA (US);
Abstract
A screw shaft feed mechanism includes a screw shaft (25) rotatably supported by a frame (19) and extending in a shaft feed direction of a work table (shaft fed base) (1); a nut member (39) rotatably supported by the work table (1) and engaged with the screw shaft (25); a screw shaft drive motor (29) for rotating the screw shaft (25); and a nut drive motor (57) for rotating the nut member (39), wherein both screw shaft driving means and nut driving means are provided with a motor having a device detecting a rotational angle of a motor shaft, respectively. In a positioning control method for a screw shaft feed mechanism, the screw shaft drive motor (29) and the nut drive motor (57) are activated simultaneously; the screw shaft drive motor (29) and the nut drive motor (57) are deactivated in such a way that a time difference is produced between when the screw shaft (25) stops and when the nut member (39) stops; and the work table (1) is located by controlling deceleration of any one of the screw shaft drive motor (39) and the nut drive motor (57) which is stopped later. In this positioning control method, it is possible to locate the work table at high speed and simultaneously at high positioning accuracy.