Cutting by use of rotating axially moving tool – Tool of specific diverse material
Reexamination Certificate
2001-08-22
2003-12-02
Bishop, Steven C. (Department: 3722)
Cutting by use of rotating axially moving tool
Tool of specific diverse material
C407S119000, C408S230000, C428S547000
Reexamination Certificate
active
06655882
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a twist drill having a sintered cemented carbide body, and like tools, and the use thereof.
2. Background Information
A twist drill, and the like tools, having sintered cemented carbide bodies (cermets) of this type are described in International Patent Applications published as WO 99/10549, WO 99/10550, WO 99/10551, WO 99/10552 and WO 99/10553 of the Assignee herein. The aforementioned International Patent Applications furthermore describe the use of these sintered cemented carbide bodies as cutting inserts and cutting bits and for manufacturing drills and cemented carbide tools and tool inserts of all kinds. The entire content of said international patent applications hereby is expressly incorporated herein by reference.
Thus, there is further known from U.S. Pat. No. 5,992,546 issued to Heinrich et al. on Nov. 30, 1999, corresponding to International Patent Application No. WO 99/10552, an elongate rotary tool for machining materials, the rotary tool comprising an elongate body at a first end, a shank at a second and opposite end, the elongate body and the shank sharing a common axis, at least one face on the elongate body at an end opposite the shank, wherein the at least one face defines a corresponding flute extending along the elongate body toward the shank, at least one flank on an end of the elongate body at an end opposite the shank, and a cutting edge at a juncture of the at least one face and the at least one flank, wherein the at least one flank, the at least one face, and the cutting edge at the juncture thereof of the elongate rotary tool comprise a cermet comprising at least one hard component and a binder.
There is also known from U.S. Pat. No. 6,010,283 issued to Heinrich et al. on Jan. 4, 2000, corresponding to International Patent Application No. WO 99/10553, a cutting tool for chip forming machining of workpiece materials, the cutting tool comprising a rake face over which chips formed during the chip forming machining of workpiece materials flow, a flank face, and a cutting edge, for cutting into the workpiece materials to form the chips, formed at a junction of the rake face and the flank face, wherein at least the rake face, the flank face and the cutting edge of the cutting tool comprise a cermet comprising at least one hard component and a binder.
U.S. Pat. No. 6,022,175 issued to Heinrich et al. on Feb. 8, 2000, which corresponds to International Patent Application No. WO 99/10550, refers to a rotary tool comprising an elongate tool body having an axially forward end and an axially rearward end, a hard insert affixed to the tool body at the axially forward end thereof, and the hard insert comprising a WC-cermet comprising tungsten carbide and a binder.
There is also known from U.S. Pat. No. 6,170,917 issued to Heinrich et al. on Jan. 9, 2001, corresponding to International Patent Application No. WO 99/99/10551, a pick-style tool comprising an elongate tool body having an axially forward end and an axially rearward end, a hard insert affixed to the tool body at the axially forward end thereof, and the hard insert comprising a cermet comprising tungsten carbide and a binder.
There is also known from U.S. Pat. No. 5,788,427 issued to Zitzlaff et al. on Aug. 4, 1998, an indexable insert having two parallel cutting edges on opposite sides of an indexable insert body in the form of a rectangular block. In the intermediately placed top surface descending toward the center line thereof, there is a chipbreaking structure comprising alternating projections and recesses. These projections and recesses constitute a row, centered on the center line, of spherical-like chipbreaking bodies, between which concave chip guiding surfaces are formed. During metalcutting operations, this provides an even flow of chips with the formation of short chips which are free of grooves and tears along the edges.
Further, there is known from U.S. Pat. No. 5,967,706 issued to Hughes, Jr. on Oct. 19, 1999, a high speed milling cutter using a wedge to secure an insert within a pocket of the milling cutter wherein the wedge is tapered in both the axial direction and the radial direction. A screw urges the wedge within a tapered cavity to press the insert within the pocket along the axial wedge angle while rotation of the cutter creates centrifugal forces urging the wedge radially outward, thereby forcing the wedge against the radial wedge surface to further compress the insert within the pocket. The insert pocket may be extended to radially encompass the insert, thereby providing additional support against centrifugal forces for the insert.
There is also known from U.S. Pat. No. 6,145,606 issued to Haga on Nov. 14, 2000, a cutting insert which comprises a pair of top surfaces which intersect to form a chisel edge, and a pair of concave surfaces wherein each one of the concave surfaces is adjacent to and intersects its corresponding one of the top surfaces. The cutting insert further includes a pair of end surfaces and a pair of arcuate surfaces. One of the arcuate surfaces intersects the one top surface and further intersects the one end surface whereby the one arcuate surface joins the one top surface and the one end surface. The other of the arcuate surfaces intersects the other top surface and further intersects the other end surface whereby the other arcuate surface joins the other top surface and the other end surface.
It is known from German Patent No. 32 11 047 and from its corresponding U.S. Pat. No. 34,180 that in the case of cemented carbides comprising a binder consisting of cobalt, nickel or iron, under certain sintering conditions and after the addition of specific additives to the hard component powder blends, a binder enriched layer which however is at the same time depleted in or free of solid solution carbides will form near the surfaces of the sintered cemented carbide bodies, while a binder depleted layer which however is at the same time enriched in solid solution carbides will form beneath the enriched layer.
As used herein, the term “cermet” refers to those materials, only, which comprise at least one metallic phase and at least one ceramic phase such as tungsten carbide (WC). Diamond and graphite per se are not considered to be “ceramic” in the language of the present application. Thus, materials comprising diamond or graphite embedded in a metal matrix or bonded with a metal alloy do not form a “cermet” in the sense of the present invention.
It is the object of the present invention to provide a novel twist drill, and the like tools, having sintered cemented carbide bodies which comprise a binder consisting of cobalt, nickel and iron, but which, compared with presently available cermets having a binder comprising cobalt, nickel, and iron, exhibit improved mechanical properties, in particular an enhanced fatigue resistance and at the same time an enhanced toughness.
The invention teaches that this object can be achieved by a twist drill, comprising: a tip portion; a flute portion disposed adjacent to said tip portion; a central longitudinal axis; said tip portion being substantially cone shaped; said tip portion having a base portion and a top portion; said base portion being substantially wider than said top portion; said base portion being disposed immediately adjacent to said flute portion of said drill; said top portion being disposed on said tip portion opposite to said base portion; said tip portion comprising: a first chip face forming a portion of said conical surface of said tip portion; a second chip face forming a portion of said conical surface of said tip portion; a chisel edge arrangement configured to initiate drilling a material to be drilled; said chisel edge arrangement being disposed between said first chip face and said second chip face; said first chip face having a first end disposed adjacent to said chisel edge arrangement and a second end disposed opposite to said first end and adjacent to said body portion of said drill; said second chip face having a first end
Heinrich Hans-Wilm
Schmidt Dieter
Wolf Manfred
Bishop Steven C.
Kennametal Inc.
Nils H. Ljungman & Associates
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