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. 12, 2016
Filed:
Dec. 25, 2012
Sumitomo Electric Industries, Ltd., Osaka-shi, JP;
Sumitomo Electric Hardmetal Corp., Itami-shi, JP;
Kawasaki Jukogyo Kabushiki Kaisha, Kobe-shi, JP;
Hisao Oka, Osaka, JP;
Yoshiji Sato, Itami, JP;
Kiichi Meguro, Itami, JP;
Junichi Tamura, Kakamigahara, JP;
Satoshi Suzuki, Kakamigahara, JP;
Sumitomo Electric Industries, Ltd., Osaka-shi, JP;
Sumitomo Electric Hardmetal Corp., Itami-shi, JP;
Kawasaki Jukogyo Kabushiki Kaisha, Kobe-shi, JP;
Abstract
A small diameter portion having an outside diameter smaller than a diameter of the drill is formed on a front end side of a body of the drill in which a cutting edge includes at least two portions, that is, a rotation center side cutting edge portion and an outer peripheral side cutting edge portion and point angles of the respective cutting edge portions reducing gradually from the rotation center side cutting edge portion to the outer peripheral side cutting edge portion. The cutting edge with the point angles varied is formed in the small diameter portion. A flat cutting edge having an inclination angle β of 30° or less with respect to a line perpendicular to an axis of the drill is provided in a step portion formed between the small diameter portion and a large diameter portion.