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:
Aug. 09, 2016
Filed:
Jun. 06, 2012
Hirofumi Higashiwaki, Mie, JP;
Eiji Hashimoto, Chiba, JP;
Manabu Saito, Tokyo, JP;
Masao Watanabe, Tokyo, JP;
Tatsuo Nakahata, Tokyo, JP;
Hirofumi Higashiwaki, Mie, JP;
Eiji Hashimoto, Chiba, JP;
Manabu Saito, Tokyo, JP;
Masao Watanabe, Tokyo, JP;
Tatsuo Nakahata, Tokyo, JP;
MAKOTOLOY CO., LTD., Osaka, JP;
FUJI JUKOGYO KABUSHIKI KAISHA, Tokyo, JP;
Abstract
Provided is a step-shaped drill bit including at least two stepped cutting edges that are axially provided. A cutting edge of a first step from a tip is formed so as to satisfy at least one of the following conditions. That is, a number of blades is smaller, a point angle of the cutting edge is larger, or a clearance angle of the cutting edge is larger than that of cutting edges of a second and subsequent step(s). As a result, a thrust resistance during a perforation can be reduced compared with a case in which the first step cutting edge is formed such that the number of blades, the point angle of the cutting edge and the clearance angle of the cutting edge are the same as those of the second and subsequent step(s).