Cutting by use of rotating axially moving tool – Processes – Bit detachable
Reexamination Certificate
1999-04-05
2001-04-24
Bishop, Steven C. (Department: 3722)
Cutting by use of rotating axially moving tool
Processes
Bit detachable
C407S042000, C407S113000, C408S224000, C408S233000, C408S713000
Reexamination Certificate
active
06220795
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to combined spotting (or centering) drills and milling cutters.
BACKGROUND OF THE INVENTION
Spotting and centering drills with indexable replaceable inserts are used to form spotting and centering holes in a workpiece. These holes provide an accurate center position for twist, spade or other drills used to drill a straight, deep bore in the workpiece. One such drill is described in U.S. Pat. No. 5,259,707 to Keller (“the '707 patent”). The cutting insert of the tool described in the '707 patent features a V-shaped cutting edge. The two sides of the cutting blade are symmetrical, with the apex of the “V” disposed coaxial with the axis of rotation of the drill. This design is problematic because at the center of rotation no cutting forces are applied. Instead, workpiece material at the axis of rotation is pressed aside by the point of the insert, which increases cutting forces and temperature of the tool, decreases tool life and, in some cases, decreases feed rates.
Indexable drills featuring a shank and multiple cutting inserts, with the point of the insert being radially offset from the rotational axis, are known in the art. Such a drill is described in U.S. Pat. No. 5,758,997 to Mealey et al. (“the '997 patent”). FIG. 9 of the '997 patent suggests it is known to radially offset the point of a cutting insert relative to the rotational centerline of the tool. The cutting tool of the '997 patent is principally intended to drill holes, typically using a spotting hole for a guide. Because of the use of even numbers of inserts to balance drilling forces, and the relatively shallow cutting angles of the inserts of the drill of the '997, it is apparent the drill is not designed to form spotting or centering holes.
SUMMARY OF THE INVENTION
One aspect of the present invention is a spotting drill and milling cutter comprising a shank having an insert pocket and a rotational axis, and an insert mounted in the pocket. The insert has a primary cutting edge and a secondary cutting edge, with the primary cutting edge having a point that is radially offset with respect to the rotational axis. The insert further includes a primary radial relief surface associated with the primary cutting edge.
Another aspect of the present invention is an insert for a spotting drill and milling cutter having a shank with an insert pocket for receiving the insert and a rotational axis. The insert comprises a primary cutting edge having a point that is radially offset with respect to the rotational axis when said insert is received in the insert pocket and a secondary cutting edge. The insert further includes a primary radial relief surface associated with the primary cutting edge.
Yet another aspect of the present invention is a method of forming a spotting hole in a workpiece. The method is accomplished using a rotary cutter having a rotational axis, a primary cutting edge, a secondary cutting edge and a tertiary edge. The primary cutting edge terminates at a point that is radially offset 0.001″ to 0.1 00″ with respect to the rotational axis and the tertiary edge has a cutting portion extending between the point and the rotational axis. The method involves causing relative rotation between the workpiece and the rotary cutter and then causing relative feed between the rotary cutter and the workpiece so that the point first contacts the workpiece, and then the primary cutting edge and the cutting portion of the tertiary edge contact the workpiece and remove material from the workpiece so as to form a circular cavity. Next, relative feed between the rotary cutter and the workpiece is effected so as to cause the secondary cutting edge to engage the workpiece and remove material from the workpiece so as to form a spotting hole concentric with the circular cavity.
REFERENCES:
patent: 2575239 (1951-11-01), Stephens
patent: 3878905 (1975-04-01), Schaumann
patent: 4060335 (1977-11-01), Holloway et al.
patent: 4072438 (1978-02-01), Powers
patent: 4115024 (1978-09-01), Süssmuth
patent: 4302135 (1981-11-01), Lillie
patent: 4338050 (1982-07-01), Ozer et al.
patent: 4355932 (1982-10-01), Koppelmann et al.
patent: 4642001 (1987-02-01), Gill et al.
patent: 4844669 (1989-07-01), Tsujimura et al.
patent: 4859123 (1989-08-01), Koesashi et al.
patent: 4927303 (1990-05-01), Tsujimura et al.
patent: 5259707 (1993-11-01), Keller
patent: 5340246 (1994-08-01), Tukala
patent: 5474407 (1995-12-01), Rödel et al.
patent: 5758997 (1998-06-01), Mealey et al.
patent: 5839857 (1998-11-01), Paya
patent: 5893683 (1999-04-01), Johnson
patent: 5951214 (1999-09-01), Rothballer et al.
patent: 5957755 (1999-09-01), LaFlamme
patent: 5971676 (1999-10-01), Kojima
patent: 6039515 (2000-03-01), Lamberg
patent: 0677825 (1979-08-01), None
Product Information Sheet entitled “Ingersoll Indexable Spotting Drill—Series FAK”, date: at least as early as Apr. 24, 2000.
VIT's 90° Indexable Carbide Centering Drill, vol. 1, Issue 1, Nov. 20, 1996.
Indexable Carbide Spot Drill & Countersink Tools Brochure, undated.
Bishop Steven C.
Downs Rachlin & Martin PLLC
Vermont Indexable Tooling, Inc.
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