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:
Apr. 28, 1992
Filed:
Oct. 24, 1990
Kunio Arai, Atsugi, JP;
Yasuhiko Kanaya, Machida, JP;
Hitachi, Seiko, Ltd., Kanagawa, JP;
Abstract
A spindle and Z-axis unit comprises a spindle housing and a hollow rotor shaft rotatable and axially movable with respect to the spindle housing. The rotor shaft carries a collet at its lower end for chucking a machine tool such as a drill bit. The tool is changed in the collet by pneumatic actuation of a diaphragm which actuates a push rod within the rotor shaft to move the collet axially against a spring bias to clamp and unclamp the tool. The shaft is moved in the Z-direction along with a thrust bearing assembly by a screw nut which actuates a road to move the rotor shaft in the Z-direction to drill a workpiece after a pressure foot has first been moved to clamp the workpiece with respect to the spindle. Thus, the moving weight or mass previously attributable to parts such as a spindle saddle and spindle housing can be eliminated without impairing the reliability and chucking force of the collet mechanism.