Drill bit for hand drills
Patent 4840519 Issued on June 20, 1989. Estimated Expiration Date: 
June 24, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 24, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3333490 Tool chuck Drill chuck for percussion drilling Tool holder for drilling machines, drilling device as well as drills and set of drills Patent #: 4702651 InventorApplicationNo. 07/065944 filed on 06/24/1987US Classes:408/226, Including detailed shank279/123, Jaws279/19, Lost motion279/60, Obliquely guided reciprocating jaws408/240Clamping jawsExaminersPrimary: Bilinsky, Z. R.Attorney, Agent or FirmInternational ClassesB25D 17/00 (20060101)B23B 31/00 (20060101) B25D 17/08 (20060101) Foreign Application Priority Data1983-12-27 DEAbstractThe invention contemplates an improved drill-bit construction wherein the shank by which the bit is clamped is characterized by (a) three angularly spaced grooves which are continuous over their entire length of engageability to the jaws of a multi-jaw chuck, (b) at least one of the grooves being closed at its rear end, (c) the rear end of the closed-end groove is at no greater offset than 5-mm from the rear end of the bit, and (d) the diameter of the cutting part of the bit shank is greater than the diameter of the clamping part of the shank, to an extent which at most results from shaped formation of the chip-removal groove. | |
