Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B51/00—Tools for drilling machines
  • B23B51/08—Drills combined with tool parts or tools for performing additional working
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
  • B23B31/005—Cylindrical shanks of tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2231/00—Details of chucks, toolholder shanks or tool shanks
  • B23B2231/02—Features of shanks of tools not relating to the operation performed by the tool
  • B23B2231/0216—Overall cross sectional shape of the shank
  • B23B2231/0232—Hexagonal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23B—TURNING; BORING
  • B23B2231/00—Details of chucks, toolholder shanks or tool shanks
  • B23B2231/02—Features of shanks of tools not relating to the operation performed by the tool
  • B23B2231/026—Grooves
  • B23B2231/0268—Radial grooves

Definitions

• the present invention relates to drill bits and related tools. More particularly, it pertains to variations in bits which accommodate drilling or shaping into a variety of different materials and which may be secured or coupled firmly to the chuck of a power tool.
• a wood auger as shown in 3,136,347-Linquist, has a screw tip followed by cutting edges beyond which a spiral ridge serves as an auger for cut chips of wood.
• the upper end of the shank has an enlarged square collar beyond which is a hex-shaped end portion.
• Similar wood drills have had either round or square coupling portions.
• Twist drills more commonly have a uniform diameter like the one shown in 3,880,546-Segal. They typically have a round coupling configuration, although some have included a flat side to enable a better grasp by certain types of chucks.
• a reamer has been combined with a drill, the reamer function serving to dress and/or shape the hole initially formed in accordance with the drilling function.
• Typical examples are U. S. Patents 1,355,065-Simpson, 2,389,909-Hofbauer and 3, 667,857-Shaner et al.
• a twist drill is removably attached to a following reamer as shown in 2,369,120-Ferries.
• twist drills i n One problem i n most of the foregoing combined twist drills and reamers is that the manufacturing operations necessary to form the different cutting and shaping surfaces are exceedingly complex and, thus, costly. Any combination which is composed of a plurality of parts clearly is less desirable from at least the standpoint of cost. In addition, some of the prior drill bits are either more expensive to form or are less flexible as to mode of coupling to a drill because of complexity of shape of the coupling portion. Another problem in the use of twist drills i n conjunction with hand-held power tools is the danger to the operator when the rotating drill bit comes to asudden stop (as when, in the case of boring wood, one encounters an unseen knot or as in the case of high speed drilling in hard metal).
• a further object of the present invention is to provide new and improved drill bits which may be modified to any of several different forms each of which has features which accommodate particular characteristics of various materials being drilled.
• a drill bit in accordance with one feature of the present, invention, includes an elongated one-piece rod composed of tool steel.
• One end portion of the rod has a hexagonal cross-section. Its other end portion is pointed and is shaped along its length to define a twist drill of uniform external diameter and having a spiral groove with one margin defining a cutting edge facing the direction of rotation.
• An intermediate portion of the rod is formed along its length to follow the other end portion into a hole and is shaped to smooth the wall of the hole behind that one end portion.
• FIG. 1 is a side elevational view of one embodiment of a drill bit
• Figures 2, 3 and 4 individually are cross-sectional views taken respectively along lines 2-2, 3-3 and 4-4 in Figure 1;
• Figure 5 is a side elevational view of another embodiment;
• Figure 6 is a cross-sectional view taken along the line 6-6 in Figure 5;
• Figure 7 is a side elevational view of a further embodiment.
• FIG 8 is a side elevational view of still another embodiment.
• a twist drill 10 is formed from an elongated one-piece rod 12 composed of tool steel. Its upper end portion 14 has a hexagonal cross-section. Its lower end portion has a pointed free end 16 from which it is shaped along its length to define a twist drill 18. Twist drill 18 is of uniform external diameter and has a spiral groove 20 with one margin 22 that defines a cutting edge facing in a direction of rotation. An intermediate portion of rod 12, between upper and lower end portion 14 and 16, is formed along its length to define a reamer 24. Reamer 24 is joined to upper portion 14 by a smooth portion 26 and, in this case, includes slanted grooves 28 each with one margin 30 that defines a shaving edge. From the juncture 32 of upper end portion 14, all of the way to free end 16, the external diameter of rod 12 is continuous and uniform.
• Upper end portion 14 is of hexgonal cross section in all versions to be described.
• the ordinary twist drill in common use has a round upper end or coupling portion which continues into a spiral groove throughout the remainder of its length to its pointed end. If of a sufficiently hard tool steel and properly sharpened, it will form a reasonably clean hole in very hard metals. However, the hole form tends to be less smooth when drilled in many other materials such as soft metals, a variety of plastics and fiberous bodies. The walls of the hole may be left with burrs or scores. When a deep hole is needed, a soft plastic or the like tends to clog the grooves of a twist drill.
• twisting drill portion 18 need not be very long in itself, regardless of the overall length needed for the bit.
• Reamer 24 can then have a groove 28 which is larger, so as better to serve as an auger of the cut particles out of the hole.
• the cutting edge of margin 30 of groove 28 serves to dress the hole.
• Smooth portion 26 then may serve, in the case of drilling into softer materials, to finally smooth the finish of the hole, removing any imperfections left by reamer 24.
• portion 26 is more like a honing operation. With harder materials, the surface of smooth portion 26 might be inlaid with diamond dust or the like for achieving that function. Being of uniform diameter entirely to juncture 32, the entire drill bit is subject to being readily manufactured on the same machine, if desired. Also, the top of the bit always is free to avoid interference with the surface which surrounds the formed hole. Specifically as shown in Figure 1, the twist of groo've 28 is opposite of that of the twist of groove 20.
• margins 22 and 30 face in the same direction. That not only allows the reamer portion to auger cut material on out of the hole, but it also allows insertion into the hole of a cutting lubricant when necessary for harder materials.
• a circular shear groove 34 disposed near juncture 32.
• Groove 34 is defined to enable the body of the drill bit, beyond the chuck, to shear off when the drill bit in any way becomes stuck in the hole.
• the depth of groove 34 is selected in view of the size of the drill bit to insure that the drill bit shears free before a driving hand-held power tool will spin backwardly an amount sufficient to cause injury to the operator.
• Groove 34 preferably is continuous but need not be.
• a drill bit 40 again includes an upper end portion 42 of hexagonal cross-section that includes a shear groove 43. Portion 42 is joined at 44 to a smooth-walled section 46 which continues into an upper twist drill portion 48. Portion 48 has a groove 50 with a cutting margin 52. Portion 40 then continues into a reamer portion 54 which includes longitudinally oriented splines 56 separated by grooves 58. Each spline 56 defines a cutting edge that faces in the direction of rotation as defined by margin 52. Continuing beyond portion 54 is a lower twist drill portion 60 which, as before, includes a groove 62 with a cutting edge margin 64 and finally terminates in a pointed end 66.
• Reamer portion 54 is of the straight type which often is more suitable when dealing with particularly hard materials in which a hole is to be formed. At least with some hard materials, a smoother finish can be provided with this variety of reamer as compared with a twisted reamer. Nevertheless, the straight reamer still can leave blemishes in the shaved surface.
• the purpose of upper twist drill portion 48 is to make a final sweep of the wall so as to remove any burrs left by the reamer, as well as to auger on out of the hole particles
• twist drill portion 60 tends to ride more smoothly within an already formed bore.
• a drill bit 70 has its upper or coupling portion 72 of hexagonal cross-section as before.
• Portion 72 includes a shear groove 73 and then continues into a smooth portion 74 following which is a twist reamer 76 that has a spiral groove 78 with a shaving margin 80 at one side of the groove.
• twist reamer 76 is a pointed twist drill portion 82 that has its spiral groove 84 with a cutting-edge margin 86.
• hex portion 72 preferably has an additional detenting groove 88.
• a drill bit 90 again has its coupling or upper end 92 of hexagonal cross-section. Included in portion 92 is a circumferential detenting
• portion 92 continues into a smooth portion 94 following which is a pointed twist drill portion 96 that has a spiral groove 98 with acutting-edge margin 100.
• hex portion 92 has a uniform cross-sectional area which is significantly larger than that of portions 94 and 96.
• portion 92 is sized to be almost as large as the maximum that can be accepted by a conventional drill chuck designed to grasp any of a series of bits of different diameters up to that maximum. All bits in a set of different sizes should have the same diameters of large portion 92. Thus, even the smallest drill in the set has a large coupling portion that is more securely grasped by the chuck. This avoids the frequent problem with ordinary bits, wherein the smaller bits most frequently slip inside such a chuck.
• hex portion 2 is larger than the drill stem of portions 94 and 96, no shear groove has been included. In case of a blockage to rotation of the stem, the bit stem will shear off without the danger posed when the stem is larger than the hex shank.
• the twist drill portions and the reamer portions are shown as being of approximately the same length. That is not necessary. Depending upon the materials to be drilled, one portion might be considerably longer than another. In most cases, a reamer or smoothing portion need not be very long as compared with the lower twist drill portion. In other cases, as mentioned above, it may, on the other hand, be desired to shorten the relative length of the twist drill portion. In any case, it is also to be noted that no matter what additional sections are included, the lower twist drill portion may still be used for those applications that require only that portion. Thus, the user would not need to have ordinary twist drills and, in using just the twist drill portion, it still would be exceedingly well gripped by the common form of chuck.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Drilling Tools (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=22174867

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• 1983
  • 1983-03-04 WO PCT/US1983/000299 patent/WO1984003461A1/en unknown
  • 1983-03-04 EP EP19830901289 patent/EP0139636A1/de not_active Withdrawn
  • 1983-03-04 AU AU14717/83A patent/AU1471783A/en not_active Abandoned

Non-Patent Citations (1)

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