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:
Feb. 22, 1994
Filed:
Jul. 15, 1992
Applicant:
Inventors:
Peter C Chaconas, Glyndon, MD (US);
Paul A Stone, Silver Run, MD (US);
Assignee:
Black & Decker Inc., Newark, DE (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B23B / ;
U.S. Cl.
CPC ...
408211 ; 408225 ;
Abstract
A self-centering twist drill bit 20 is formed with a 'fishtail' cutting section 32 having major cutting lips 72 and 74 on a working end 26 thereof at a point angle of 190.degree.. Tip relief surfaces 76 and 78 trail cutting lips 72 and 74. A pilot tip 38 on the working end 26 extends axially from the 'fishtail' cutting section 32 and is formed with a split point having leading cutting edges 40 and 42 and minor cutting lips 46 and 48. Outer surfaces 58 and 60 of pilot tip 38 are each formed with a radial relief and a back taper and joins with cutting section 32 along fillets 92 and 100 which are also radially relieved.