Cutting by use of rotating axially moving tool – With means to apply transient – fluent medium to work or product – Including tool with duct
Reexamination Certificate
2000-01-07
2001-09-04
Wellington, A. L. (Department: 3722)
Cutting by use of rotating axially moving tool
With means to apply transient, fluent medium to work or product
Including tool with duct
C408S059000, C408S144000, C408S230000, C408S713000
Reexamination Certificate
active
06283682
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a helically fluted twist drill device.
More specifically, the present invention relates to a helically fluted twist drill device for cutting materials.
2. Information Disclosure Statement
Three-flute twist drills otherwise known as core drills are primarily used for enlarging and finishing drilled, cast or punched holes. Generally, such three-flute drills will not produce original holes.
Some three-flute drills are manufactured by means of a process which includes the step of providing a cylindrical blank which defines three equidistantly spaced longitudinally extending flutes and bores.
The cylindrical blank or rod is extruded when it is still in its soft state. The extruded material is then heat treated or sintered to bring such material to its final state of hardness.
Subsequently, a helical flute is machined between adjacent bores such that the resultant machined twist drill includes three flutes or channels which extend helically from a shank portion disposed adjacent to one end of the blank to a second end of the blank.
Next, the second end of the blank is machined to provide a point. The bores are provided so that a cutting fluid under pressure can be fed through the twist drill while the drill is rotating at high speed. The cutting fluid flows from the shank to the point so that lubrication of the twist drill within the drilled hole is accomplished. Also, the cutting fluid flows from the point of the twist drill back through the flutes. Such flow of the cutting fluid from the point through the flutes conveys the cut material from the point towards the shank of the twist drill. The aforementioned process is known as chip evacuation.
Accordingly, it is desirable that the cross sectional area of the flutes or channels be as large as possible so as to avoid clogging of the same by chips or material being drilled or cut during the drilling operation.
Nevertheless, when large flutes are machined, there is a tendency to cut the flute in such a way that the surface of the flute exposes the adjacent bore. If such exposure occurs, the resultant twist drill will be useless.
Also, in order to machine the flutes, various shape grinding wheels have been required. The multiplicity of grinding wheels of various shapes has often been necessary in order to generate the flute form needed for that particular drill size. The use of special grinding wheels can be very expensive with a single wheel costing between $300.00-$400.00. Also, 12-15 different wheels are required in order to make various drill sizes.
Additionally, the operation of truing the form of the grinding wheels as such wheels wear is labor intensive.
The present invention overcomes the aforementioned problems by providing an arrangement in which twist drills of various sizes can be machined using a single straight grinding wheel such as a type IAI grinding wheel with a {fraction (1/32)} inch-{fraction (1/16)} inch radius.
In the grinding operation according to the present invention, the axis of the grinding wheel is disposed at an approach angle within the range 2-4 degrees relative to the longitudinal axis of the twist drill.
Therefore it is a primary objective of the present invention to provide a fluted twist drill and a method of manufacturing the same which overcomes the problems associated with the prior art arrangements.
Another object of the present invention is the provision of a fluted twist drill having at least three flutes. Each flute defines a flute surface which when taken in a section normal to the longitudinal axis of the twist drill is of generally S-shaped configuration so that hooking the flutes is inhibited, that is the flutes have no undercut areas.
A further object of the present invention is the provision of a fluted twist drill having at least three flutes which can be manufactured in various sizes using a standard straight grinding wheel.
Other objects and advantages of the present invention will be readily apparent to those skilled in the art by a consideration of the detailed description contained hereinafter taken in conjunction with the annexed drawings.
SUMMARY OF THE INVENTION
The present invention relates to a helically fluted twist drill device for cutting materials. The device includes a cylindrical core having a first diameter, a longitudinal axis and a first and a second extremity, the second extremity defining a cutting point. At least three portions extend helically outwardly away from the core so that the portions define a second diameter. The arrangement is such that adjacent portions define therebetween a helical flute. Each of the flutes has a flute surface which is of S-shaped configuration when viewed as a cross section disposed normal to the longitudinal axis, the cross section being viewed in a direction from the first towards the second extremity. Each of the portions further defines a helical bore connected to a source of a cutting fluid for permitting a flow of the cutting fluid through the bore towards the cutting point. The arrangement is such that in use of the device, the cutting fluid conveys the materials away from the cutting point through each flute. The first diameter has a dimension within a first range which is 20-35% of a dimension of the second diameter. Also, the second extremity of the core and adjacent portions is of cusp-shaped configuration for defining the cutting point so that wandering of the drill device is inhibited.
Many modifications and variations of the present invention will be readily apparent to those skilled in the art by a careful consideration of the detailed description of the present invention described hereinafter taken in conjunction with the annexed drawings. However, such modifications and variations fall within the spirit and scope of the present invention as defined by the appended claims.
REFERENCES:
patent: 4134704 (1979-01-01), Jackley et al.
patent: 4826368 (1989-05-01), Tikal et al.
patent: 4898503 (1990-02-01), Barish
patent: 4932815 (1990-06-01), Krauss
patent: 5046902 (1991-09-01), Zubov et al.
patent: 6045305 (2000-04-01), Plummer
patent: 3709647 (1988-10-01), None
Besly Drills, Turboflute Drills are not just for Deep Hole Drilling, Catalog, Revised 1995, Besly Products Corp. 100 Dearborn Ave. S. Beloit IL 61080.
Hertel “T.F. Drill Solid Carbide Drills” Hertel 9041 Executive Pk Dr. Bldg 5 Knoxville TN 37923 Brochure. No Date.
Konet “Regrinding Procedures For KCC/KSC Drills” Brochure—No Date.
Archer David J.
Carter Monica S.
Wellington A. L.
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