WO1998005459A1 - Foret a langue d'aspic - Google Patents

Foret a langue d'aspic Download PDF

Info

Publication number
WO1998005459A1
WO1998005459A1 PCT/US1997/013766 US9713766W WO9805459A1 WO 1998005459 A1 WO1998005459 A1 WO 1998005459A1 US 9713766 W US9713766 W US 9713766W WO 9805459 A1 WO9805459 A1 WO 9805459A1
Authority
WO
WIPO (PCT)
Prior art keywords
point
spade bit
chip
bit according
spade
Prior art date
Application number
PCT/US1997/013766
Other languages
English (en)
Inventor
Gregory A. Phillips
Thomas O. Schimke
Jürgen Wiker
Original Assignee
Vermont American Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vermont American Corporation filed Critical Vermont American Corporation
Priority to AU39088/97A priority Critical patent/AU3908897A/en
Publication of WO1998005459A1 publication Critical patent/WO1998005459A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27G—ACCESSORY MACHINES OR APPARATUS FOR WORKING WOOD OR SIMILAR MATERIALS; TOOLS FOR WORKING WOOD OR SIMILAR MATERIALS; SAFETY DEVICES FOR WOOD WORKING MACHINES OR TOOLS
    • B27G15/00—Boring or turning tools; Augers

Definitions

  • the present invention relates to a drill bit. More specifically, the present invention relates to a spade type drill bit. More particularly still, the present invention relates to a spade type drill bit m which the chip flow direction all along the cutting edge points in the same direction .
  • the present invention uses a rounded corner design which increases the surface area and reduces the temperature at the edges of the bit resulting m a longer tool life and a reduction in the need for sharpening. Also see U.S. Patent Nos . 5,099,933 and 5,145,018.
  • the present invention overcomes many of the deficiencies of the prior art.
  • the present invention features a drill bit design in which chip flow all along the cutting edge always goes m the same direction. This is accomplished in the illustrated embodiment of the present invention by aligning the chip velocity vectors to be always perpendicular to a line drawn from each point of the main cutting edge to the center axes of the spade bit. By having all of the velocity vectors point in the same direction, the chip flow is also always in the same direction.
  • the present invention results in a spade bit in which the quality of the hole drill is improved and the ease of hole cleaning is improved. Due to the fact that the chip flow direction is always in the same direction, the chips do not break up into smaller chips during the drilling process. This makes it easier to clear out the hole. In addition, by causing the chips to flow in a single direction, vibrations are reduced which results in a superior quality hole .
  • conventional spade bit designs included spurs on the outer edges of the bit which resulted in high localized temperatures and a high wear rate.
  • Spade bits designed in accordance with the present invention will preferably have a rounded corner on the outer edge which not only increases surface area in order to reduce maximum temperature along the rounded edge, it also results in a bit that advantageously exhibits longer tool life and maintains its cutting edge without sharpening longer relative to conventional designs. Further, by eliminating the spurs used in conventional designs, the present invention eliminates the problem wherein the drill bit would tend to "grab" when exiting the hole.
  • the present invention and its energy deficiency is particularly advantageously when drilling a plurality of holes using cordless drills having limited battery life.
  • Further embodiments of the invention provide a cutting edge having chip breaker elements and a novel self threading point design.
  • a spade bit comprising a shank and cutting head.
  • the cutting head includes a point and a pair of cutting edges extending generally radially outward from the point.
  • the cutting edges create velocity vectors of cuttings which are generally parallel to each other along essentially the entire cutting edge.
  • the cutting edges also include chip breakers which provide for chip flow having a uniform speed.
  • Figures 1A, IB and 1C are respectively a top view and a side and edge projection view of a first embodiment drill bit according to the present invention.
  • Figures 2A, 2B and 2C are respectively a top view and a side and edge wise view of a conventional drill bit design.
  • Figure 3A is a front view in partial perspective, of a spade type drill bit according to the present invention.
  • Figure 3B is a detail of the cutting edge portion of Figure 3A.
  • Figure 4A is a front view in partial perspective, of a conventional drill bit design
  • Figure 4B is an enlargement of the cutting edge portion of Figure 4A.
  • Figure 5 illustrates an edge view of a drill bit according to the present invention illustrating the chip velocity vectors.
  • Figure 6 illustrates a bit according the present invention cutting into a wood piece.
  • Figure 7 illustrates a conventional spade bit and chip velocity vectors.
  • Figure 8 illustrates a conventional spade bit exiting a wooden work piece.
  • Figure 9 illustrates a conventional spade bit and the hook angle of the spur portions thereof.
  • Figures 10A, 10B and IOC respectively illustrate a top view and side and edge projections of a second embodiment of a spade bit according to the present invention.
  • Figure 11 is an enlargement of the edge projection of Figure IOC.
  • Figure 12 is an enlargement of the edge projection of the head portion of the drill bit potion of Figure 10A.
  • Figure 13 is a front view in partial perspective of a drill bit m accordance with the second embodiment of the invention.
  • Figure 14 is a partial perspective view of the head portion of the drill bit of Figure 13.
  • Figure 15 is a front partial perspective view of a spade type drill bit featuring four chip breakers, two located on each side of the mam cutting edge.
  • Figure 16A, 16B and 16C are respectfully top view and side and edge projection of third embodiment of the invention having a threaded point .
  • Figure 17 is an enlargement of the cutting edge potion of the drill bit of Figure 16A.
  • Figure 18A is a front up standing view and partial perspective of a drill bit in accordance with a third embodiment .
  • Figure 18B is a detail of the threaded point of the spade type drill bit of Figure 18A.
  • Figure 19 is another detail and partial perspective of the threaded point of the spade type drill bit according to the third embodiment of the invention.
  • Figure 20 is a depiction of a threaded spade type drill bit having a conventional thread design.
  • a bit having a cutting head 6 is provided.
  • the bit includes an elongated shaft 4.
  • the end of the shaft which is opposite the cutting head 6 is preferably provided with hexagonal flats in order to permit it to received in a drill chuck.
  • the present drill bit always directs the flow of chips produced during drilling all along the cutting edge in the same direction.
  • the velocity vectors 10 are depicted in the illustrated embodiment, the angle of the velocity vectors 10 is illustrated at an angle of approximately 5.7° which is typical for a 1 inch spade blade. It will be appreciated by the artisan however that the velocity vector angle will vary depending on the thickness of the spade drill and its diameter.
  • FIG. 7 illustrates typical chip velocity vectors 10' which would result from a conventional drill design.
  • the velocity vectors 10' are not parallel to each other and the chip flow along the cutting edge 24' varies from point to point along that edge.
  • the angle of the chip velocity vectors with respect to the center line 12 of the drill bit varies between about 24.5° along the main cutting edge 25 i.e. the edge closest to the point 16, to about 9° at the outer most point of the main cutting edge 27'.
  • the angle of the chip velocity vector with respect to the center line of the drill bit at the point on the main cutting edge closest to the point 16 is designated as ⁇ .
  • the angle of the chip velocity vector with respect to the center line 12 at the outer most point of the main cutting edge is designated as y .
  • Applicant has also found that when cutting chips using a drill bit having chip velocity vectors 10 such as shown in Figure 5, the chips do not break up into smaller chips as they are created which makes it easier to clear the chips out: of the hole being created. This tends to reduce vibration and leads to a better quality hole.
  • Applicant has found that when using a drill bit made in accordance with Figures 1, 3 and 5, that chips easily come out of the hole thereby minimizing the problem of conventional bits where chips tend to clog up the hole and place additional strain on the motor and in severe cases even blocking the movement of the drill bit and damaging the drill motor.
  • conventional drill bit designs include edge spurs 26 and 28 on the outer edges of the bit.
  • the spurs frequently experience high localized temperatures and exhibit high wear out rates.
  • the drill bit made according to the present invention preferably has rounded corners 20 and 21 which increases the surface area and reduces the maximum temperature as compared to drill bits equipped with edge spurs. This results in a tool having a longer life and a bit that retains the sharpness of its edge better relative to the conventional design.
  • FIGs 8 and 9 illustrate additional disadvantage of drill bits equipped with conventional edge spurs.
  • the spurs 26 and 28 of conventional spade bits tend to grab the work piece 30. Once the outer most parts of the spurs have exited the material 30, the spurs cause the drill bit to pull itself aggressively back into the material. This is due to the hook angle ⁇ on the spurs of the spade bit as illustrated in Figure 9. In a typical conventional drill bit, the angle ⁇ is about 15°.
  • both the main cutting edges 22 and 24 basically exit the material at the same time which leads to a smooth cut, less wood blowout and less splintering.
  • FIG. 10-15 A second embodiment of a drill in accordance with the present invention is illustrated in Figures 10-15.
  • chip breakers 35 and 36 are provided on the cutting edges 22 and 24 respectively.
  • the chip velocity vectors 10 are the same in all directions along the cutting edges 22 and 24; i.e., the chip velocity vectors 10 are all designed to point essentially in the same parallel direction. In accordance with the second embodiment, however, chips will be broken up into smaller chips as they are created.
  • spade bits of prior art the chips have the tendency to flow in different directions, due to the fact that the chip velocity vectors are not aligned. Thus, the chip flow angles are not aligned either. As a result, additional energy is consumed to break up the chips into smaller pieces, or at least to deform them so that they can flow in one direction.
  • the present invention spade bit aligns the velocity vectors in one single direction. Therefore, no energy is consumed to deform them or to break them apart . In addition, bigger chips are also easier to clear out of the hole .
  • the above equation illustrates that the chip velocity would be different at each point along the cutting edge of a spade bit, as r varies and f is constant for the whole spade bit.
  • Breaking the chips into two to three pieces per side means those two or three pieces can flow in one direction due to the aligned velocity vectors and nearly constant speed. Two or three chips per side is the preferred design to get the full benefit. Breaking the chips into more pieces would make it more difficult to clear them out of the hole.
  • FIG. 11 is an expanded edge view of a drill bit in accordance with the second embodiment of the invention having chip breaker points 35 and 36.
  • each of the chip breakers are triangularly shaped and have as their included angle, an angle similar to the included angle of the point 16 of the spade bit.
  • triangularly shaped chip breaker points are preferred, other shapes may also be used including non-pointed i.e. rounded chip breakers and/or angles other than that of the point 16 may be used.
  • Figures 12 and 14 further illustrate the non- limiting structure of the chip breaker embodiment.
  • a detailed view of a spade having four chip breakers 35, 35' and 36, 36' is illustrated.
  • the length of the chip breaker i.e. the length it extends away from the cutting edges 22 and 24 is shown to be varied. This is illustrative of the fact that while the presently preferred chip breaker is a triangular shape at a certain length, combinations of different shapes (i.e., configurations) and different lengths or sizes are also within the scope of the present invention.
  • Figure 16-20 illustrate a third embodiment of the present invention.
  • This embodiment encompasses essentially all of the structures and benefits of the first embodiment and additionally includes a threaded point structure.
  • the threaded spade bit as illustrated in Figure 16A, 16B and 16C has the advantage of being self-feeding, i.e. it does not require the user to apply thrust force while drilling. Details of the threaded point 16 for a spade bit are best seen in Figures 17-19.
  • the number of threads can vary depending upon the particular spade bit, but would typically vary in the range of between about 16 to 26 TIP. The lower number of threads the more aggressively the drill bit will feed itself into the material.
  • FIG 17 there is depicted a 20 TIP thread ground using a plated grinding wheel 40 as shown in the dashed lines in Figure 17.
  • the threads are preferably ground using the wheel 40 adjusted at an angle slightly different from the angle A of the point 16.
  • the point angle A is about 36°.
  • the angle B which is the included angle at which the threads are ground, would be in the range from about 32° to about 34°.
  • Figure 18B is an expanded view of a drill head having a threaded point 16 in accordance with the third embodiment.
  • Figure 18B an exemplary configuration of a threaded point 16 formed in accordance with the invention is illustrated.
  • Figure 19 for an alternative perspective view of an exemplary configuration for the threaded portion 37 of the point 16.
  • a spade bit having cutting edges designed in accordance with the first embodiment of the present invention bit with a conventionally threaded point 16 is illustrated in Figure 20.
  • a drill having a conventionally threaded point design 38 and assuming the operator is drilling in wood, should the bit hit a nail or another metal object, the thread is likely to become damaged. Slight damage to the threads 38 on the top end of the point 16 render the threads useless. Damaged threads do not function to self feed the drill bit.
  • a self threading point designed according to the third embodiment of this invention overcomes the problem by providing threads which are ground to their full depth at the bottom of the point 16 and of gradually decreasing depth towards the top of the point.
  • the depth of the thread 37' is less than the depth of the thread 37''. This is accomplished by adjusting the grinding wheel angle as described above in connection with angles C and D, thus leaving more material on the top or tip end of the point 16 so that it can withstand the impact for example of hitting a nail or any other kind of metal type material possibly embedded in the wood.
  • the angles C and D are typically identical, which gives r se to the disadvantages noted above .
  • the size, number and placement of the chip breaker members may vary as may the particular configuration of the threaded point design.
  • the basic design consideration of the first embodiment of the invention is to ensure that the chip flow direction all along the cutting edge of the drill is always in the same direction. As long as the cutting blade is designed so that the chip velocity vectors are always generally perpendicular to a line drawn from each point on the main cutting edge relative to the center access to the spade bit, the advantages of the invention can be realized.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Forests & Forestry (AREA)
  • Drilling Tools (AREA)

Abstract

La présente invention décrit un foret à langue d'aspic dans lequel le sens du flux des copeaux le long du taillant (22, 24) du foret se propage toujours dans la même direction. Comme le sens du flux des copeaux est commandé par le vecteur de vitesse des copeaux, le taillant (22, 24) du foret a été conçu de manière à ce que la vitesse des copeaux soit généralement toujours perpendiculaire à une ligne tirée entre le taillant principal (22, 24) du foret et son axe principal.
PCT/US1997/013766 1996-08-08 1997-08-07 Foret a langue d'aspic WO1998005459A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU39088/97A AU3908897A (en) 1996-08-08 1997-08-07 Spade bit

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US2373596P 1996-08-08 1996-08-08
US60/023,735 1996-08-08
US90702997A 1997-08-06 1997-08-06
US08/907,029 1997-08-06

Publications (1)

Publication Number Publication Date
WO1998005459A1 true WO1998005459A1 (fr) 1998-02-12

Family

ID=26697538

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1997/013766 WO1998005459A1 (fr) 1996-08-08 1997-08-07 Foret a langue d'aspic

Country Status (2)

Country Link
AU (1) AU3908897A (fr)
WO (1) WO1998005459A1 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004080632A1 (fr) 2003-03-11 2004-09-23 Credo Technology Corporation Trepan en forme de pelle
US6957937B2 (en) 2001-02-20 2005-10-25 Maxtech Manufacturing Inc. Spade bits with angled sides
US7246976B2 (en) 2003-10-21 2007-07-24 Textron Innovations Inc. Spade bit
US7267513B2 (en) * 2003-03-11 2007-09-11 Credo Technology Corporation Spade drill bit
US7416371B2 (en) 2004-05-04 2008-08-26 Irwin Industrial Tool Company Wood boring bit with increased speed, efficiency and ease of use
US7473056B2 (en) 2005-10-20 2009-01-06 Irwin Industrial Tool Company Spade bit
US7887269B2 (en) * 2007-10-10 2011-02-15 Robert Bosch Gmbh Spade bit with improved cutting geometry
US8979444B2 (en) 2007-06-07 2015-03-17 Robert Bosch Gmbh Cutting bit adapted to cut metal and wood and associated method
WO2022253976A1 (fr) * 2021-06-04 2022-12-08 Iml Instrumenta Mechanik Labor Gmbh Mèche, résistographe et son utilisation pour étudier la nature du bois

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2543206A (en) * 1948-07-23 1951-02-27 Benjamin D Aufderheide High-speed wood-boring bit
US3920350A (en) * 1974-02-11 1975-11-18 Stanley Works Spade bit
FR2421022A1 (fr) * 1978-03-31 1979-10-26 Centre Techn Ind Mecanique Lame d'agrandissement a faces de coupe planes
US4286904A (en) * 1979-07-16 1981-09-01 Parker Manufacturing Company Wood bit
GB2130935A (en) * 1982-04-07 1984-06-13 Vanguard Fixings Limited Wood drill bits
SU1151374A1 (ru) * 1981-04-22 1985-04-23 Всесоюзный Научно-Исследовательский Инструментальный Институт Пластина дл сборных перовых сверл
US5273380A (en) * 1992-07-31 1993-12-28 Musacchia James E Drill bit point

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2543206A (en) * 1948-07-23 1951-02-27 Benjamin D Aufderheide High-speed wood-boring bit
US3920350A (en) * 1974-02-11 1975-11-18 Stanley Works Spade bit
FR2421022A1 (fr) * 1978-03-31 1979-10-26 Centre Techn Ind Mecanique Lame d'agrandissement a faces de coupe planes
US4286904A (en) * 1979-07-16 1981-09-01 Parker Manufacturing Company Wood bit
SU1151374A1 (ru) * 1981-04-22 1985-04-23 Всесоюзный Научно-Исследовательский Инструментальный Институт Пластина дл сборных перовых сверл
GB2130935A (en) * 1982-04-07 1984-06-13 Vanguard Fixings Limited Wood drill bits
US5273380A (en) * 1992-07-31 1993-12-28 Musacchia James E Drill bit point

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6957937B2 (en) 2001-02-20 2005-10-25 Maxtech Manufacturing Inc. Spade bits with angled sides
EP1606073A4 (fr) * 2003-03-11 2011-04-20 Credo Tech Corp Trepan en forme de pelle
EP1606073A1 (fr) * 2003-03-11 2005-12-21 Credo Technology Corporation Trepan en forme de pelle
US7267513B2 (en) * 2003-03-11 2007-09-11 Credo Technology Corporation Spade drill bit
WO2004080632A1 (fr) 2003-03-11 2004-09-23 Credo Technology Corporation Trepan en forme de pelle
US7246976B2 (en) 2003-10-21 2007-07-24 Textron Innovations Inc. Spade bit
US7416371B2 (en) 2004-05-04 2008-08-26 Irwin Industrial Tool Company Wood boring bit with increased speed, efficiency and ease of use
US7473056B2 (en) 2005-10-20 2009-01-06 Irwin Industrial Tool Company Spade bit
US7905690B2 (en) 2005-10-20 2011-03-15 Irwin Industrial Tool Company Spade bit
US7922429B2 (en) 2005-10-20 2011-04-12 Irwin Industrial Tool Company Spade bit
US8147174B2 (en) 2005-10-20 2012-04-03 Irwin Industrial Tool Company Spade bit
US8979444B2 (en) 2007-06-07 2015-03-17 Robert Bosch Gmbh Cutting bit adapted to cut metal and wood and associated method
US7887269B2 (en) * 2007-10-10 2011-02-15 Robert Bosch Gmbh Spade bit with improved cutting geometry
WO2022253976A1 (fr) * 2021-06-04 2022-12-08 Iml Instrumenta Mechanik Labor Gmbh Mèche, résistographe et son utilisation pour étudier la nature du bois

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