| 摘要 |
PCT No. PCT/BE92/00035 Sec. 371 Date May 16, 1994 Sec. 102(e) Date May 16, 1994 PCT Filed Aug. 28, 1992 PCT Pub. No. WO93/05264 PCT Pub. Date Mar. 18, 1993.The present invention discloses a core bit comprised of a body having blades thereon, with several cutters on each blade, and nozzles that emerge on the face of the body. The nozzles deflect liquids substantially obliquely with respect to an axis of rotation of the body, preferably according to an angle greater than 45 DEG . The nozzle defines an elbow portion formed from a molded portion of the body and from an insert opposite said molded portion on the side of the largest curvature of radius of the elbow. An inner hollow core retaining element includes an axial annular lip to engage an annular groove in the body. The annular lip and groove define a passage gap to regulate coring liquid flow therethrough. An inner portion between the blades has a cross-section with a curve having a most forward point adjacent the core, the curve having a first convex portion from the forward point to adjacent the insert and a second convex portion extending laterally outwardly.
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