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. 22, 1986
Filed:
May. 01, 1984
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
A drill made of cemented carbide, is constructed for compensating for the brittleness of cemented carbide to increase its cross-break strength. For this purpose, the ratio of the diameter c of the web portion (1) to the drill diameter d is set in the range of 25% to 35%, and the flute width ratio (b:a) is set in the range of 0.4:1 to 0.8:1. Further, to decrease the cutting resistance on the drill, the radial rake .theta..sub.r angle of the cutting lip 4 measured at positions spaced at least 2/3 of the drill diameter toward the outer peripheral side is set in the range of -5.degree. to positive valves. Furthermore, to promote the chip ejecting function, the relative distance L between the cutting lip 4 and the flute wall 5 opposed thereto, is decreased.