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:
Jul. 22, 1997
Filed:
May. 17, 1995
Max W Durney, Penngrove, CA (US);
Castle Tool Machinery, Incorporated, Petaluma, CA (US);
Abstract
A spade drill bit device including an elongated shaft formed for rotation about a longitudinal axis thereof, and a flattened blade portion at one end of said shaft. The blade portion has generally planar and parallel opposing faces, and defines opposing side edges, and an end cutting edge therebetween. The cutting edge includes a pair of opposing side spurs each having spur tip portions positioned at the lateral extremities of the cutting edge and terminates at the corresponding side edge. A cutting edge triangular-shaped center tip is included axially aligned with the longitudinal axis, and having a distal end extending beyond the side spurs. The center tip is defined by downward edge portions extending away from the distal end. The cutting edge further includes respective converging edge portions extending between and connecting each side spur to the center tip. Each converging edge portion intersects a respective downward edge portion at a corresponding curved nadir portion positioned closer to the center tip than the respective spur portion.