| 摘要 |
<p>PCT No. PCT/EP96/04854 Sec. 371 Date Jul. 21, 1998 Sec. 102(e) Date Jul. 21, 1998 PCT Filed Nov. 6, 1996 PCT Pub. No. WO97/17153 PCT Pub. Date May 15, 1997A drilling tool is proposed comprising a shaft which has both a chuck shaft suitable for fitting in machine tools and a drill-holding shaft, known per se, with chuck grooves and (optionally) coolant ducts. A replaceable drill bit (1) is fitted in a positive fit and detachably on the shaft. The drill bit can consist of a homogenous material and has cutting edges (2) inclined radially outwards and backwards; these cutting edges can be formed in one piece from the drill bit material or are composed of blades mounted in the central region and made from the drill bit material and complementary blades orignating from a cutter plate screwed onto the drill bit. The invention proposes that the cutting edges (2) should be aligned symmetrically about the drill bit axis and the cutting edges should be in cutting engagement over the entire radius of the bore to be drilled. Special securing devices comprising a pin with a fixing bore (7) and carrier grooves (5) on the outer circumference of the drill bit make it possible to fix the drill bit in matching securing devices on the drill shaft. In one particular embodiment, the drill bit in the drill shaft is clamped on matching wedge-shaped fitting surfaces. The invention is used preferably for spot drilling or boring of solid material as well as packet drilling and spot drilling of oblique surfaces of workpieces, the preferred diameter range being 5 to 50 mm. The drill bit can be re-ground or fitted with new screw-cutting plates or replaced after use with a new plate by simply releasing the positive-fit mount.</p> |
