The present application relates to drill bits and, more particularly, to drill bits including a pilot tip to bore through wood, metal and plastics.
One of the most commonly used drill bits to drill through metal is a twist drill formed with a chisel edge at the working end of the drill bit. The chisel edge is formed perpendicular to the axis of the drill bit and usually extends across the small portion of the drill bit diameter. Also, the chisel edge extends equally on opposite sides of the drill bit axis. A cutting edge extends from each opposite end of the chisel edge and tapers axially rearwardly to the outer periphery of the drill bit diameter. In use, the chisel edge is the first portion of the drill bit to engage a workpiece. The chisel edge engages the workpiece and works and extrudes the material in the intermediate vicinity rather than forming chips swarf, sawdust and the like for extraction. A work material enables the drill bit to begin to move into the material of the workpiece whereby the cutting edges begin to cut the material to form removable chips which are discharged via helical flutes running axially rearwardly from the chisel edge and the cutting edges.
While a drill bit with a chisel edge is satisfactory for some drilling operations, it does not provide holes with accurately located centers or round holes. For example, it tends to skip away from the desired location of the hole as a rotating chisel edge engages the workpiece. Further, in the out of round characteristics of the drill bit or tool holder connected to the shank of the drill bit is transmitted to the working end while drilling the hole.
European Patent Publication No. EP0315643 discloses a drill bit having a pilot tip which extends axially ahead of an outer cutting portion. The pilot tip has a smaller diameter than the outer cutting portion. In use, the pilot tip cuts a pilot hole which self-centers the drill bit. Next, the outer cutting portion cuts a main hole in the workpiece which corresponds to the diameter of the drill bit.
A drill bit sold by the Applicant also has a pilot tip which extends axially ahead of an outer cutting portion. The pilot tip has a “split point” cutting edge arrangement to cut the self-centering pilot hole and the outer cutting portion has a pair of major cutting edges arranged on opposite sides of the axis to cut the primary hole. The split point has two inner minor cutting edges arranged on opposite sides of the axis. The two inner minor cutting edges are spaced apart and connected at the extreme tip of the split point by a slight chisel edge. The split point also has an outer minor cutting edge that extends from the end of each inner minor cutting edge and tapers axially rearward to the outer periphery of the pilot tip. In use, the two inner minor cutting edges engage a workpiece to initiate the drilling operation slightly in advance of the engagement of the workpiece by the outer minor cutting edges. The chisel edge does not work or extrude the material in its immediate vicinity, like in the case of the common twist drill mentioned above, because the chisel edge is insignificantly small. The chips created by the inner and the outer minor cutting edges are separate from each other and are therefore smaller in size.
Once the pilot tip begins drilling the self-centering pilot hole, the major cutting edges of the outer cutting portion engage the workpiece and create chips which are also separate from those created by the minor cutting edges of the pilot tip. This arrangement produces smaller chips during the drilling operation which, in turn, reduces resistance to the passage of the drill bit through the workpiece as the drilling process progresses. The drill bit has debris channels in the form of a pair of helical flutes to transport the chips away from the cutting edges and out of the hole being drilled in the workpiece. Smaller chips are naturally easier to convey along the flutes and are less likely to clog up the flutes. A clogged flute creates the problem of significantly increased resistance to the passage of the drill bit through the workpiece. Deeper flutes transport such chips and other debris more easily and are less prone to clogging. However, deeper flutes also result in a thinner web that reduces the strength of the dill bit. A compromise is met by a web that tapers radially outwardly and axially rearward from the pilot tip of the working end towards the drill bit shank. This provides deeper flutes in the region of the working end where efficient debris removal is most important. Also, it provides a thicker web towards the shank where robustness is important. The prior art drill bit has a tapering web with a thickness increasing from the tip portion to the shank portion at a uniform taper rate. See U.S. Pat. Nos. 6,050,754, 6,190,097, 7,267,514 7,520,703, and 8,470,515 each of which is assigned to Applicant, and each of which is incorporated by reference in its entirety.
In one aspect, this application relates to a drill bit having a thinner web thickness at its tip and a smaller helix angle to improve pull-through, drilling life and efficiency.
According to another aspect, an elongated drill bit with a longitudinal axis and a nominal diameter comprises a shank at one end and a working end is the other end. A flute portion is formed between the shank and the working end. The shank, working end, and flute portion are continuous with one another and are generally unitarily formed. The working end comprises a pilot tip with a cutting portion. The flute portion includes a tapered web that has a web thickness at the working tip of about 7% to 20% of the nominal diameter at the tip of the working end. Also, the flute portion includes a helix angle of from about 30° to 35°.
Implementations of this aspect may include one or more of the following features. A second cutting portion may be formed at a terminus of the flute portion axially spaced from the pilot tip first cutting portion. The second cutting portion may include a pair of cutting edges on opposed sides of the pilot tip.
According to another aspect, an elongated drill bit with a longitudinal axis includes a shank at one end having a nominal diameter, a working end at an opposite end, and a flute portion between the shank and the working end. The shank, the working end and the flute portion re continuous with one another. The flute portion includes a helix angle of approximately 30° to 35°. The working end includes a pilot tip with a first cutting portion and a second cutting portion axially spaced from the first cutting portion. The second cutting portion is at a terminus of the flute portion and includes a pair of cutting edges on opposing sides of the pilot tip. A tapered web is formed in the flute portion. A thickness of the web at the tip of the working end is approximately 9% to 15% of the nominal diameter.
Implementations of this aspect may include one or more of the following features. The drill bit may have: (a) a nominal diameter of ¼ inch or less and the thickness of the web at the tip of the working end is approximately 13% to 15% of the nominal diameter; (b) a nominal diameter between 17/64 inch and 21/64 inch the thickness of the web at the tip of the working end is approximately 11% to 13% of the nominal diameter; or (c) a nominal diameter greater than or equal to 11/32 inch and the thickness of the web at the tip of the working end is approximately 9% to 10% of the nominal diameter. The drill bit may have: (a) a nominal diameter of 17/64 inch or less and the web thickness at the shank is approximately 68% to 76% of the nominal diameter; (b) a nominal diameter between 9/32 inch and ⅜ inch and the web thickness at the shank is approximately 61% to 65% of the nominal diameter; or (c) a nominal diameter 25/64 inch or larger and the web thickness at the shank is about 55% to 60% of the nominal diameter. A thickness of the web at the shank may be approximately 55% to 76% of the nominal diameter of the bit. The web taper rate may be approximately 0.070 to 0.074. The helix angle may be approximately 34.5°.
The working end and at least a portion of the flute portion may formed of a first metal section, and the shank is formed of a second metal section that is welded to the first metal section, the second metal section having a material toughness higher than the first metal section. A length to diameter ratio of the first metal section may be between approximately 0.7 and 3.0. The hardness of the first metal section may be at least approximately 65 HRc. The hardness of the second metal section may be approximately 45-55 HRc. At least one of the first and second metal sections may be heat treated so as to have a recognizable different appearance than the other of the first and second metal sections.
In another aspect, a set of drill bits includes a first drill bit having a first nominal diameter, a second drill bit having a second nominal diameter, and a third drill bit having a third nominal diameter. Each of the drill bits has a shank at a first end, a working end at a second end, and a flute portion between the shank and the working end. The shank, the flute portion and the working end are continuous with one another. The flute portion has flutes with a helix angle of approximately 30° to 35° and a tapered web. The first drill bit has a nominal diameter of 17/64 inch or less and a thickness of the web at the working end of approximately 13% to 15% of the nominal diameter. The second drill bit has a nominal diameter between 17/64 inch and 21/64 inch and a thickness of the web at the working end of approximately 11% to 13% of the nominal diameter. The third drill bit has a nominal diameter greater than or equal to 11/32 inch and a thickness of the web at the working end of approximately 9% to 10% of the nominal diameter.
Implementations of this aspect may include one or more of the following features. The first drill bit may have a web thickness at the shank of approximately 68% to 76% of the nominal diameter. The second drill bit may have a web thickness at the shank is approximately 61% to 65% of the nominal diameter. The third drill bit may have a web thickness at the shank is about 55% to 60% of the nominal diameter. Each of the webs may have a web taper rate of approximately 0.070 to 0.074. Each of the helix angles may be approximately 34.5°. Each of the working ends and at least a portion of each of the flute portions may be formed of a first metal section, and each of the shanks may be formed of a second metal section that is welded to the first metal section, where the first metal section may have a first material hardness that is higher than a second material hardness of the second metal section.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The present invention will become more fully understood from the detailed description and the accompanying drawings.
The following description of the drawings is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Referring to
The fluted portion 26 is formed with a pair of helical flutes 30 defined by a pair of helical lands 32 formed at a helix angle α measured with respect to the axis X-X. The helix angle α is between approximately 30° and 35°. In one embodiment, the helix angle may be approximately 34.5°. The helical flutes 30 and the helical lands 32 extend axially rearward from the working end 24 to the shank 28 and each have a pitch S. The pitch S is the linear distance on the drill bit between one full 360° revolution of a helical land. The pitch S is determined by the helix angle α and the major or nominal diameter D of a the fluted portion 26 of the drill bit 20, according to the formula: S=πD/(tan α). For example, in a ½ drill bit, the pitch S may be between approximately 1.87 and 3.36 inches, e.g., between approximately 1.87 and 2.24 inches. In a ½″ drill bit where the helix angle α is approximately 34.5°, the pitch is approximately 2.29 inches.
Referring to
The pilot tip 36 is also formed with a pair of rounded circumferential outer surfaces 56, 58. Each outer surface 56, 58 extend axially rearward on opposite sides of the pilot tip 36. The outer surface 56 is formed with a forward edge 60 and a trailing edge 62 (in the direction of rotation R). The outer surface 58 is formed with a forward edge 64 and a trailing edge 66 (in the direction of rotation R).
When viewed from above, as shown in
When viewed from the side, as shown in
Returning to
Each second cutting edge 70, 72 run radially inwardly in a substantially straight line from the periphery of the major diameter D towards the pilot tip 36. The second cutting edges 70, 72 are substantially on a plane which passes through the longitudinal axis X-X. In the region adjacent the pilot tip 36, the second cutting edge 70 begins to curve towards the working end 24 to form a radius at a forward edge 78 of a fillet 80. The second cutting edge 70 merges with the forward edge 60 of the outer surface 56 at the fillet 80. Likewise, the second cutting edge 72 extends from the periphery of the major diameter D towards the pilot tip 36 and eventually curves in an identical manner into a radius at a forward edge 82 of a fillet 84. The second cutting edge 72 merges with the forward edge 64 of the outer surface 58 at the fillet 84.
Each fillet 80, 84 begins at a respective forward edge 78, 82 with a relatively large radius and extends rearward in a curved path from the respective forward edge 78, 82, wherein the radius becomes progressively smaller until each fillet terminates in an approximately right-angle shaped corner 86, 88, respectively. In addition, each fillet 80, 84 extends radially inward from the respective forward edge 78, 82 to a respective trailing corner 86, 88 in the same manner as the rounded outer surfaces 56, 58. Accordingly, the fillets 80, 84 create relief behind the forward edges 78, 82.
As discussed above, relief is provided behind the edges mentioned above. For example, the primary clearance face 74, the secondary clearance face 75 the fillet 80, and the outer surface 56, which trail, the second cutting edge 70, the fillet forward edge 78 and the pilot tip forward edge 60, respectively, create relief behind these edges in the manner described above. Thus, when the drill bit 20 is used to drill a hole in a workpiece, these trailing surfaces do not engage and rub against the walls of the hole. Similarly, the primary clearance face 76, secondary clearance face 77, the fillet 84, and the outer surface 58, which trail, the second cutting edge 72, the fillet forward edge 82 and the pilot tip forward edge 64, respectively, also create relief behind these edges. Thus, when the drill bit 20 is used to drill a hole in a workpiece, these trailing surfaces do not engage and rub against the walls of the hole.
As is shown in
Referring to
Each helical land 32 has an inner surface 92 that defines the shape of a respective flute 34. Each land inner surface 92 extends axially rearward from a respective outer cutting edge 44, 46 and a respective second cutting edge 70, 72. Each outer cutting edge 44, 46 forms a boundary between a respective land inner surface 92 and a respective primary clearance face 48, 50. Likewise, each second cutting edge 70, 72 forms a boundary between a respective land inner surface 92 and a respective primary clearance face 74, 76. The land inner surfaces 92 act as a rake face to both the outer cutting edges 44, 46 and the second cutting edges 70, 72. Accordingly, the land inner surfaces 92 each effectively have a rake face angle RA, as measured from a plane parallel to the axis X-X, that is equal to the helix angle α. The cutting angle of the second cutting edges 70, 74 equals 90°−(RA+CA). The cutting angle of the outer cutting edges 44, 46 equals 90°−(RA+the relief angle of the primary relief face 48, 50).
Referring to
Referring to
The following Table 1 provides examples of embodiments of bits that fall within the scope of the present disclosure:
The web thickness at the tip K is about 13% to 15% of the nominal diameter for bits having a nominal diameter of ¼ inch of less. The web thickness K is about 11% to 13% of the nominal diameter for bits having a nominal diameter between 17/64 inch and 21/64 inch. The web thickness K is about 9% to 10% of the nominal diameter for bits having a nominal diameter greater than or equal to 11/32 inch. This is compared to 22% to 34% ( 3/64 inch- 5/32 inch), 14% to 20% ( 11/64 inch- 19/64 inch), 11% to 14% ( 5/16 inch-½ inch), respectively, of conventional drill bits with nominal diameter sizes. Thus, the web thickness K is about 60% less than the web thickness of conventional drill bits.
The web thickness at the shank (J) is about 68% to 76% of the nominal diameter for bits having a nominal diameter of 17/64 inch or less. The web thickness at the shank J is about 61% to 65% of the nominal diameter for bits having a nominal diameter between 9/32 inch and ⅜ inch. The web thickness at the shank J is about 55% to 60% of the nominal diameter for bits having a nominal diameter 25/64 inch or larger. The web taper rate ((J-K)/L3) for all nominal diameters is approximately 0.070 to 0.074. The helix angle for all nominal diameters is approximately 30° to 35°, in particular approximately 34.5°.
In an embodiment, the drill bits of the present disclosure may be bi-metal drill bits composed of two different metal materials, similar to the drill bits disclosed in the aforementioned U.S. patent application Ser. No. 14/205,577. Referring to
For example, the first metal may be a high-speed steel, e.g., M42 (8% cobalt), M35 (5% cobalt), or M2, with an HRc hardness of at least approximately 65 HRc, for example an HRc in the high 60s. The second metal may be ordinary tool steel, such as 65 Mn steel, with an HRc hardness between approximately 45-55 HRc. The length to diameter ratio of the first metal portion 106 has been optimized to provide good cutting action for sheet-metal having a thickness of ¼ inch or less. For example, a length to diameter ratio of the first metal section is between approximately 0.7 and 3.0. The lengths of the first metal portion 106 and the second metal portion 108 have been optimized: (1) to allow the first metal section to be able to be held by a welding machine during welding; (2) to allow passage of sufficient current through the first metal section for good electrical resistance welding; (3) to provide better life of the drill bit; (4) to provide better bending toughness in the second metal portion after the first metal section breaks through the sheet-metal; and (5) to minimize the cost of the components of the drill bit.
The drill bits of the present disclosure dramatically and unexpecrtedly improve drilling life as compared to the prior art design for drill bits, while still preserving acceptable drilling speed. Referring to
Referring to
Referring to
It is believed that this dramatic increase in life while maintaining the drilling speed is due to the smaller web thickness (K) at the tip, the smaller helix angle, and the more dramatic web taper rate to a sufficiently large web thickness (J) at the shank, along with the larger helix angle (e.g., approximately 34.5°. In certain embodiments, the bi-metal construction of the bit may further contribute to the improved life.
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
This application claims priority, under 35 U.S.C. §119(e), to U.S. Provisional Patent Application No. 61/871,446, filed on Aug. 29, 2013, titled “Self-Centering Drill Bit.” This application is also a continuation-in-part of U.S. patent application Ser. No. 14/205,577, filed Mar. 12, 2014, titled “Bi-Metal Drill Bit,” which claims the benefit of U.S. Provisional Application No. 61/860,987, filed on Aug. 1, 2013, and is a Continuation-in-Part of U.S. Design Patent Application No. 29/449,538, filed on Mar. 15, 2013 and a Continuation-in-Part of U.S. Design Pat. Application No. 29/468,347, filed on Sep. 30, 2013. The entire disclosures of the above applications are incorporated herein by reference
Number | Name | Date | Kind |
---|---|---|---|
460639 | Holt | Oct 1891 | A |
542223 | Johnson | Jul 1895 | A |
1350241 | Routh | Aug 1920 | A |
1398156 | Schroeder | Nov 1921 | A |
1499584 | Litchfield | Jul 1924 | A |
1570650 | Thomson | Jan 1926 | A |
1887372 | Emmons | Nov 1931 | A |
RE18182 | Emmons | May 1934 | E |
D92385 | Bardwell | Jun 1934 | S |
1984839 | Murray | Dec 1934 | A |
2101347 | Robinette | Dec 1937 | A |
2193186 | Bannister | Mar 1940 | A |
2302069 | Stephens | Nov 1942 | A |
2332295 | Bouchal | Oct 1943 | A |
D137744 | Gunderson | Apr 1944 | S |
2652083 | Emmons | Sep 1953 | A |
2708853 | MacLean | May 1955 | A |
2740974 | Lewis | Apr 1956 | A |
2769355 | Crisp | Nov 1956 | A |
2936658 | Riley | May 1960 | A |
3027953 | Coski | Apr 1962 | A |
3085453 | Mossberg | Apr 1963 | A |
3387511 | Ackart, Sr. et al. | Jun 1968 | A |
3476438 | Bower, Jr. | Nov 1969 | A |
3559513 | Hougen | Feb 1971 | A |
3592555 | Mackey, Sr. | Jul 1971 | A |
3609056 | Hougen | Sep 1971 | A |
3648508 | Hougen | Mar 1972 | A |
3655244 | Swisher | Apr 1972 | A |
3746396 | Radd | Jul 1973 | A |
3779664 | Caley et al. | Dec 1973 | A |
3825362 | Hougen | Jul 1974 | A |
4144868 | Heitbrink | Mar 1979 | A |
4210215 | Peetz et al. | Jul 1980 | A |
D257511 | Zahn | Nov 1980 | S |
4265574 | Eckle | May 1981 | A |
4340327 | Martins | Jul 1982 | A |
4383784 | Gulbrandsen | May 1983 | A |
D269495 | Finn | Jun 1983 | S |
4529341 | Greene | Jul 1985 | A |
4556347 | Barish | Dec 1985 | A |
4605347 | Jodock et al. | Aug 1986 | A |
4711609 | Seefluth | Dec 1987 | A |
4756650 | Wakihira et al. | Jul 1988 | A |
4762445 | Bunting et al. | Aug 1988 | A |
4826368 | Tikal et al. | May 1989 | A |
4878788 | Wakihira et al. | Nov 1989 | A |
4880707 | Kohno et al. | Nov 1989 | A |
4898503 | Barish | Feb 1990 | A |
4926558 | Brace | May 1990 | A |
4967855 | Moser | Nov 1990 | A |
4968193 | Chaconas et al. | Nov 1990 | A |
4983079 | Imanaga et al. | Jan 1991 | A |
5011342 | Hsu | Apr 1991 | A |
5056967 | Hageman | Oct 1991 | A |
5088863 | Imanaga et al. | Feb 1992 | A |
5152642 | Pitts et al. | Oct 1992 | A |
5230593 | Imanaga et al. | Jul 1993 | A |
5288183 | Chaconas et al. | Feb 1994 | A |
D346103 | Warner | Apr 1994 | S |
5350261 | Takaya et al. | Sep 1994 | A |
5442979 | Hsu | Aug 1995 | A |
5580196 | Thompson et al. | Dec 1996 | A |
5934845 | Frey | Aug 1999 | A |
5947660 | Karlsson et al. | Sep 1999 | A |
6007279 | Malone, Jr. | Dec 1999 | A |
D419575 | Kouvells | Jan 2000 | S |
6045302 | Orr | Apr 2000 | A |
6050754 | Thomas | Apr 2000 | A |
6089337 | Kleine et al. | Jul 2000 | A |
6102634 | Turner et al. | Aug 2000 | A |
6113321 | Mulroy et al. | Sep 2000 | A |
6190097 | Thomas | Feb 2001 | B1 |
6227774 | Haughton et al. | May 2001 | B1 |
6309149 | Borschert et al. | Oct 2001 | B1 |
6312432 | Leppelmeier | Nov 2001 | B1 |
6443674 | Jaconi | Sep 2002 | B1 |
6511268 | Vasudeva et al. | Jan 2003 | B1 |
6637987 | Lui et al. | Oct 2003 | B2 |
D482252 | Hyde | Nov 2003 | S |
6652203 | Risen, Jr. | Nov 2003 | B1 |
6705807 | Rudolph et al. | Mar 2004 | B1 |
6739872 | Turri | May 2004 | B1 |
6851898 | Ege et al. | Feb 2005 | B2 |
6857832 | Nygard | Feb 2005 | B2 |
6981496 | Szendrovari et al. | Jan 2006 | B2 |
D525840 | Bruce | Aug 2006 | S |
7178878 | Rompel | Feb 2007 | B2 |
7241085 | Frisendahl | Jul 2007 | B2 |
7258513 | Gertner | Aug 2007 | B2 |
7267514 | Wetzl et al. | Sep 2007 | B2 |
7363922 | Lang et al. | Apr 2008 | B2 |
7398840 | Ladi et al. | Jul 2008 | B2 |
7520703 | Rompel | Apr 2009 | B2 |
D594306 | Decker | Jun 2009 | S |
7578726 | Gasser | Aug 2009 | B2 |
7784381 | Ladi et al. | Aug 2010 | B2 |
7784567 | Choe et al. | Aug 2010 | B2 |
7802495 | Oxford et al. | Sep 2010 | B2 |
7851067 | Caliskanoglu et al. | Dec 2010 | B2 |
7900719 | Yao | Mar 2011 | B2 |
7913779 | Choe et al. | Mar 2011 | B2 |
D637629 | Clark | May 2011 | S |
D648356 | Clark | Nov 2011 | S |
8168009 | Mesquita et al. | May 2012 | B2 |
8201648 | Choe et al. | Jun 2012 | B2 |
D664167 | Lampe | Jul 2012 | S |
8230762 | Choe et al. | Jul 2012 | B2 |
8449041 | Monyak et al. | May 2013 | B2 |
D687871 | Liao et al. | Aug 2013 | S |
8740515 | Thomas et al. | Jun 2014 | B2 |
20020046885 | Eichhorn | Apr 2002 | A1 |
20020160235 | Caminiti | Oct 2002 | A1 |
20030017015 | Strubler | Jan 2003 | A1 |
20030202853 | Ko et al. | Oct 2003 | A1 |
20030215297 | Frisendahl | Nov 2003 | A1 |
20040052595 | Dembicks et al. | Mar 2004 | A1 |
20040191015 | Kozak | Sep 2004 | A1 |
20040253379 | Sugita et al. | Dec 2004 | A1 |
20050053438 | Wetzl et al. | Mar 2005 | A1 |
20050098358 | Nadler | May 2005 | A1 |
20050126829 | Meierhofer et al. | Jun 2005 | A1 |
20050271890 | Koecher | Dec 2005 | A1 |
20060056930 | Rompel | Mar 2006 | A1 |
20070062046 | Hsu | Mar 2007 | A1 |
20080056835 | Astrand et al. | Mar 2008 | A1 |
20080166194 | Durfee | Jul 2008 | A1 |
20080189957 | Kasper | Aug 2008 | A1 |
20090133785 | Ayada et al. | May 2009 | A1 |
20090283334 | Durairajan et al. | Nov 2009 | A1 |
20090320299 | Kuhn et al. | Dec 2009 | A1 |
20100003094 | Durfee | Jan 2010 | A1 |
20100054881 | Thomas | Mar 2010 | A1 |
20100135741 | Probst et al. | Jun 2010 | A1 |
20100183391 | Kersten | Jul 2010 | A1 |
20100192475 | Stevens et al. | Aug 2010 | A1 |
20100193255 | Stevens et al. | Aug 2010 | A1 |
20100232898 | Friedrichs | Sep 2010 | A1 |
20100276205 | Oxford et al. | Nov 2010 | A1 |
20110142707 | Choe et al. | Jun 2011 | A1 |
20110168453 | Kersten et al. | Jul 2011 | A1 |
20110186261 | Choe et al. | Aug 2011 | A1 |
20120003057 | Leyba | Jan 2012 | A1 |
20120301238 | Quinn et al. | Nov 2012 | A1 |
20130209183 | Chuo et al. | Aug 2013 | A1 |
20140126972 | Santamarina et al. | May 2014 | A1 |
20140219737 | Takai et al. | Aug 2014 | A1 |
Number | Date | Country |
---|---|---|
675842 | Nov 1990 | CH |
1018422202 | Sep 2010 | CN |
216607 | Nov 1908 | DE |
7335696 | Oct 1973 | DE |
2358048 | May 1975 | DE |
2629130 | Jan 1978 | DE |
2946103 | May 1981 | DE |
8536123 | Apr 1987 | DE |
3927615 | Feb 1991 | DE |
4117486 | Dec 1992 | DE |
19807609 | Jun 1999 | DE |
20005730 | Oct 2000 | DE |
20203232 | May 2002 | DE |
10130681 | Jan 2003 | DE |
20209797 | Nov 2003 | DE |
20211589 | Jan 2004 | DE |
102006049096 | Apr 2008 | DE |
249104 | Dec 1987 | EP |
455420 | Nov 1991 | EP |
522202 | Mar 1995 | EP |
1238732 | Sep 2002 | EP |
1260296 | Nov 2002 | EP |
1016480 | Sep 2004 | EP |
2058073 | May 2009 | EP |
2829715 | Mar 2003 | FR |
699716 | Nov 1953 | GB |
1360221 | Jul 1974 | GB |
2193913 | Feb 1988 | GB |
61226209 | Oct 1986 | JP |
62188614 | Aug 1987 | JP |
1140908 | Jun 1989 | JP |
4244311 | Sep 1992 | JP |
9225720 | Sep 1997 | JP |
2001105216 | Apr 2001 | JP |
2003225819 | Aug 2003 | JP |
3184707 | Jul 2013 | JP |
844160 | Jul 1981 | SU |
1238905 | Jun 1986 | SU |
2004037472 | May 2004 | WO |
2004011179 | Feb 2005 | WO |
Entry |
---|
“High Speed Steels (HSS) Hardness Tables” http://www.tool-tool.com/hss.htm. |
Twist Drills Standard (ASME B94:11-M-1993)—The American Society of Mechanical Engineers—pp. 1-3, 7-33, 48-49, 56-59—Mar. 31, 1994. |
National Aerospace Standard (NAS-907)—Aerospace Industries Association of America, Inc.—pp. 1-25—1986. |
Black & Decker 1983-84 Consumer Trade Catalog—p. 28—1983. |
Introduction to Mechanics of Solids—POPOV, Egor P.—“Design of Nonprismatic Beams”—pp. 360-362—1968. |
Rilliard, Arnaud—European Search Report re: European Patent Application No. 14182342—Jan. 28, 2015—10 pages—The Hague. |
The State Intellectual Property Office of People's Republic of China—Office Action re: related Patent Application No. 201510109942.8—Dec. 16, 2015—10 pages. |
The State Intellectual Property Office of People's Republic of China—Machine Translation of Office Action re: related Patent Application No. 201510109942.8—Dec. 16, 2015—10 pages. |
Number | Date | Country | |
---|---|---|---|
20140356088 A1 | Dec 2014 | US |
Number | Date | Country | |
---|---|---|---|
61871446 | Aug 2013 | US | |
61860987 | Aug 2013 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 14205577 | Mar 2014 | US |
Child | 14462935 | US | |
Parent | 29449538 | Mar 2013 | US |
Child | 14205577 | US | |
Parent | 29468347 | Sep 2013 | US |
Child | 29449538 | US |