US2735656A - Rock drilling bit - Google Patents

Rock drilling bit Download PDF

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US2735656A
US2735656A US2735656DA US2735656A US 2735656 A US2735656 A US 2735656A US 2735656D A US2735656D A US 2735656DA US 2735656 A US2735656 A US 2735656A
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insert
groove
bit
inserts
drill bit
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B10/00—Drill bits
    • E21B10/46—Drill bits characterised by wear resisting parts, e.g. diamond inserts
    • E21B10/58—Chisel-type inserts

Definitions

  • the most common type of rock drilling bits for percussion drilling comprises one or more inserts of hard metal or the like fastened in grooves formed in the bit body in such a manner that the bottoms of the grooves are at right angles to the axis of rotation of the drill bit.
  • the principal object of the present invention is to provide rock drill bits which are not attended with the abovementioned draw-backs and which are simple and inexpensive to manufacture.
  • the main feature of the drill bit according to the invention resides in that the grooves which receive the inserts have such a form that the portions of the bottom of each groove, which are situated at or near the central axis in the boring direction, are located forwardly, in the direction of boring, of the peripheral portions of the said bottom, and in that the base portion of the respective insert or inserts has or have a form corresponding to that of the bottoms of the grooves.
  • the longitudinal section of the bottom of the grooves may be curved or have the form of angles or lines broken at two or more points.
  • Fig. 1 is an end view of a drill bit of a known construction provided with only one insert.
  • Fig. 2 is a section along the line IIII in Fig. 1.
  • Fig. 3 is a section, analogous to the section in Fig. 2, through a drill bit according to the present invention, illustrating how the bottom of the groove is curved in its longitudinal direction.
  • Fig. 4 is a view in the longitudinal direction of the groove of the drill bit shown in Fig. 3, the insert being removed.
  • Fig. 5 is a section through a modified embodiment of the invention in which two inserts are accommodated in a groove with a curved bottom.
  • Fig. 6 is a section through an embodiment in which the bottom of the groove has the form of an angle.
  • Fig. 7 illustrates an embodiment in which the longitudinal section of the bottom of the groove has the form of a line broken at two points.
  • Fig. 8 is an end view of a drill bit provided with three inserts.
  • Fig. 9 is a section along the line IX-IX in Fig. 8.
  • the body 1 of the known drill bit has a groove with a straight bottom 2.
  • a hard metal insert 3 having a straight base portion.
  • the dotted line of the figure indicates the contour line formed through normal wear of the insert 3, whereby the peripheral portions 4 and 5 of the insert are almost completely worn down, while the central portion of the insert still has considerable thickness.
  • the drill bit shown in Fig. 3 which is constructed according to the invention, has the same appearance as the known drill bit shown in Figs. 1 and 2.
  • a groove '7 (Fig. 4) is formed the bottom 7" of which is curved in such a way that the portion 8 of the bottom of the groove, which is situated at the central axis of the drill bit in the direction of boring of the bit (see arrow A), is ahead or in front of the peripheral portions 9 and 10 of the said bottom.
  • this groove is fastened an insert 11 whose base portion has a form corresponding to that of the bottom 8 along the whole length thereof.
  • the dotted line of Fig. 3 indicates once again the contour line resulting from normal wearing of the insert.
  • the insert 11 is shown as consisting of the same amount of material as the insert 3 shown in Fig. 2.
  • the form that according to the invention has been given to the bottom of the groove and the base portion of the insert involves that the hard metal of the insert can be considerably better utilized than in the case of the known drill bit shown in Figs. 1 and 2.
  • the risk of cracks and ruptures occurring in these portions is reduced.
  • the insert may be formed as a single piece, two or more pieces or parts may be used placed in the same groove, as shown in Figs. 5-7.
  • the groove has a round bottom considered longitudinally of itself similarly as in the embodiment of Figs. 3 and 4, and is provided with two inserts 12 and 13 having correspondingly round bottom surfaces to fit the groove.
  • the inserts are preferably interconnected by brazing with or without webbings between them. If desirable an open clearance may be left between the adjacent ends of the inserts.
  • the longitudinal section of the groove of the embodiment shown in Fig. 6 has the form of an angle the tip of which is directed in the boring direction of the bit.
  • Both 3 of the inserts (14 and 15) shown have a straight base portion and join each other at the tip of the angle.
  • the longitudinal section of the bottom of the groove may also have the form of a line broken at two or more points as shown in Fig. 7.
  • the inserts (17, 18, 19) preferably have the same length as the corresponding portions of the bottom of the groove.
  • the invention may be adapted for most rock drilling bits with insert forms known per se, for example, bits provided with three or four cutting edges, that is, so called three or four point bits.
  • Figs. 8 and 9 show as an example a bit 20 according to the invention provided with inserts 21, 22, and 23 arranged in radially extending grooves 23 thus providing three cutting edges.
  • the inserts may advantageously be fastened in their grooves by braz- Rinsing holes and other details may be arranged in usual ways.
  • a rock drilling bit comprising a drill bit body having an elongated groove formed in its forward face considered in the direction of drilling, an elongated cutting insert of hard metal secured in said groove, said groove, in its longitudinal direction, being directed substantially transversely of the central axis of said bit body, said groove extending substantially through the central axis to the periphery of said body, the bottom of said groove situated near said central axis being located forwardly in the drilling direction of the portions of the bottom located near the periphery of said bit body, said cutting insert having curved wear surfaces facing in the direction of drilling, the portions of said wear surfaces located at and near said central axis being located forwardly, in the direction of drilling, of the portions of the wear surfaces located in the vicinity of the lateral periphery of said drill bit body, the angle between a line tangent to the portion of said wear surface most remote from said axis and said axis being greater than the angle between a line tangent to the portion of said bottom most remote from said axis and said axis

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)

Description

Feb. 21, 1956 s, P. G. HUGLUND ETAL 2,735,656
ROCK DRILLING BIT Filed March 20. 1950 2 Sheets-Sheet 1 Fig, (Pr/or an) 9- Z 1956 s. P. e. HOGLUND ETAL 2,735,656
ROCK DRILLING BIT Filed March 20, 1950 2 Sheets-Sheet 2 United States Patent ROCK DRILLING BIT Stig Per Gustav Hiiglund, Sandviken, and Anders Gustav Kindahl, Sundsvall, Sweden, assignors to- Sandvikens Jernverks Aktiebolag, Sandviken, Sweden The most common type of rock drilling bits for percussion drilling comprises one or more inserts of hard metal or the like fastened in grooves formed in the bit body in such a manner that the bottoms of the grooves are at right angles to the axis of rotation of the drill bit.
Experience has proved that the best results are obtained when the cutting edges of the inserts of the said drill type are curved. However, due to this curved form the peripheral portions of the insert are, in respect of the direction of drilling, weaker than the central portions of the insert.
Further, experience has proved that the peripheral portions of percussion drilling bit inserts wear more rapidly than the portions closer to the bit axis.
These circumstances involve that the said peripheral portions rapidly become completely worn down while the portions closer to the axis of rotation of the drill bit still possesses sufiicient thickness and strength. This is waste of expensive hard metal material because the bit has to be discarded although the cutting material has not been fully utilized.
Due to the weakening of the peripheral portions cracks and ruptures usually occur in these portions.
Several attempts have been made to eliminate the said disadvantages. Thus the inserts have been made of compound material so as to render the peripheral portions harder and more durable than the central portions. Further, drill bits have been constructed comprising a greater number of inserts disposed along the periphery of the bit than at the central portion thereof. However, the manufacture of drill bits of this type is rather complicated and expensive.
The principal object of the present invention is to provide rock drill bits which are not attended with the abovementioned draw-backs and which are simple and inexpensive to manufacture.
The main feature of the drill bit according to the invention resides in that the grooves which receive the inserts have such a form that the portions of the bottom of each groove, which are situated at or near the central axis in the boring direction, are located forwardly, in the direction of boring, of the peripheral portions of the said bottom, and in that the base portion of the respective insert or inserts has or have a form corresponding to that of the bottoms of the grooves. Thereby an advantageous distribution of hard metal is obtained which gives the new drill bit a longer life than the drill bits of the hitherto known constructions provided with the same amount of hard metal.
According to the invention the longitudinal section of the bottom of the grooves may be curved or have the form of angles or lines broken at two or more points.
The invention will now be described more in detail with reference to the accompanying drawings which show preferred embodiments of the invention.
Fig. 1 is an end view of a drill bit of a known construction provided with only one insert.
Fig. 2 is a section along the line IIII in Fig. 1.
ice
Fig. 3 is a section, analogous to the section in Fig. 2, through a drill bit according to the present invention, illustrating how the bottom of the groove is curved in its longitudinal direction.
Fig. 4 is a view in the longitudinal direction of the groove of the drill bit shown in Fig. 3, the insert being removed.
Fig. 5 is a section through a modified embodiment of the invention in which two inserts are accommodated in a groove with a curved bottom.
Fig. 6 is a section through an embodiment in which the bottom of the groove has the form of an angle.
Fig. 7 illustrates an embodiment in which the longitudinal section of the bottom of the groove has the form of a line broken at two points.
Fig. 8 is an end view of a drill bit provided with three inserts, and
Fig. 9 is a section along the line IX-IX in Fig. 8.
As will be apparent from Fig. 2 the body 1 of the known drill bit has a groove with a straight bottom 2. Into the groove is inserted a hard metal insert 3 having a straight base portion. The dotted line of the figure indicates the contour line formed through normal wear of the insert 3, whereby the peripheral portions 4 and 5 of the insert are almost completely worn down, while the central portion of the insert still has considerable thickness. Thus, the life of the known drill bit is predetermined by the peripheral portions of the insert which are weakened by the initial curved form of the cutting edge thereof, and therefore a considerable part of the hard metal of the insert will be wasted. Moreover, cracks and ruptures in most cases occur approximately at 6 as a consequence of the heavy blows caused by the percussion boring operation.
The drill bit shown in Fig. 3, which is constructed according to the invention, has the same appearance as the known drill bit shown in Figs. 1 and 2. However, in the body 7 of the new drill bit a groove '7 (Fig. 4) is formed the bottom 7" of which is curved in such a way that the portion 8 of the bottom of the groove, which is situated at the central axis of the drill bit in the direction of boring of the bit (see arrow A), is ahead or in front of the peripheral portions 9 and 10 of the said bottom. In this groove is fastened an insert 11 whose base portion has a form corresponding to that of the bottom 8 along the whole length thereof. The dotted line of Fig. 3 indicates once again the contour line resulting from normal wearing of the insert. In order to make clear the idea of the invention the insert 11 is shown as consisting of the same amount of material as the insert 3 shown in Fig. 2. The form that according to the invention has been given to the bottom of the groove and the base portion of the insert involves that the hard metal of the insert can be considerably better utilized than in the case of the known drill bit shown in Figs. 1 and 2. As a consequence of the accumulation of material at the peripheral portions of the insert the risk of cracks and ruptures occurring in these portions is reduced.
Instead of the insert being formed as a single piece, two or more pieces or parts may be used placed in the same groove, as shown in Figs. 5-7. In Fig. 5 the groove has a round bottom considered longitudinally of itself similarly as in the embodiment of Figs. 3 and 4, and is provided with two inserts 12 and 13 having correspondingly round bottom surfaces to fit the groove. In the embodiments according to Figs. 5-7 the inserts are preferably interconnected by brazing with or without webbings between them. If desirable an open clearance may be left between the adjacent ends of the inserts.
The longitudinal section of the groove of the embodiment shown in Fig. 6 has the form of an angle the tip of which is directed in the boring direction of the bit. Both 3 of the inserts (14 and 15) shown have a straight base portion and join each other at the tip of the angle.
The longitudinal section of the bottom of the groove may also have the form of a line broken at two or more points as shown in Fig. 7. In such a case the inserts (17, 18, 19) preferably have the same length as the corresponding portions of the bottom of the groove.
The invention may be adapted for most rock drilling bits with insert forms known per se, for example, bits provided with three or four cutting edges, that is, so called three or four point bits. Figs. 8 and 9 show as an example a bit 20 according to the invention provided with inserts 21, 22, and 23 arranged in radially extending grooves 23 thus providing three cutting edges.
In all of the embodiments described above the inserts may advantageously be fastened in their grooves by braz- Rinsing holes and other details may be arranged in usual ways.
It is to be understood that the invention is not limited to the particular embodiments described and shown as various other embodiments are possible within the scope of the invention.
Having now described our invention, what we claim as new and desire to secure by Letters Patent is:
l. A rock drilling bit comprising a drill bit body having an elongated groove formed in its forward face considered in the direction of drilling, an elongated cutting insert of hard metal secured in said groove, said groove, in its longitudinal direction, being directed substantially transversely of the central axis of said bit body, said groove extending substantially through the central axis to the periphery of said body, the bottom of said groove situated near said central axis being located forwardly in the drilling direction of the portions of the bottom located near the periphery of said bit body, said cutting insert having curved wear surfaces facing in the direction of drilling, the portions of said wear surfaces located at and near said central axis being located forwardly, in the direction of drilling, of the portions of the wear surfaces located in the vicinity of the lateral periphery of said drill bit body, the angle between a line tangent to the portion of said wear surface most remote from said axis and said axis being greater than the angle between a line tangent to the portion of said bottom most remote from said axis and said axis, said insert having a base portion having a form corresponding to that of the bottom of said groove, whereby the thickness of said insert, in the direction of drilling, toward the laterally remote portions of said insert is greater than toward the center thereof.
2. A rock drilling bit as defined in claim 1, and in which the insert consists of more than one piece of hard metal, and the bottom of the groove is formed of at least two plane surfaces with an angle therebetween, the height of the cutting insert in the drilling direction being greater at the portion thereof most remote from said axis than at the portion of said insert positioned closer to said axis.
3. A rock drilling bit as defined in claim 1, in which the insert consists of more than one piece of hard metal.
References Cited in the file of this patent UNITED STATES PATENTS 1,718,462 Hardsogg June 25, 1929 1,901,643 Harrington Mar. 14, 1933 2,306,598 Ellson Dec. 29, 1942 2,494,188 Meaney Jan. 10, l950 2,502,128 Curtis Mar. 28, 1950 2,507,221 Phipps May 9, 1950 2,579,268 Malherbe Dec. 18, 1951 FOREIGN PATENTS 18,443 Great Britain Aug. 7, 1913 130,187 Sweden Nov. 28, 1950 423,647 Great Britain Feb. 5, 1935 669,636 Great Britain Apr. 9, 1952 951,335 France Apr. 11, 1949
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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3006424A (en) * 1958-05-23 1961-10-31 Sandvikens Jernverks Ab Rock drill bits and cutting inserts therefor
US3059708A (en) * 1959-08-07 1962-10-23 Jersey Prod Res Co Abrasion resistant stepped blade rotary drill bit
US3080009A (en) * 1959-02-27 1963-03-05 Timken Roller Bearing Co Drill bit
US3096836A (en) * 1958-09-23 1963-07-09 Sandvikens Jernverks Ab Drill bits and cutting inserts therefor
US5429199A (en) * 1992-08-26 1995-07-04 Kennametal Inc. Cutting bit and cutting insert
US5829540A (en) * 1993-07-28 1998-11-03 Sandvik Rock Tools, Inc. Mine roof drill bit and cutting insert therefor
US6595305B1 (en) 2000-02-15 2003-07-22 Kennametal Inc. Drill bit, hard member, and bit body
US6860344B2 (en) 2001-06-25 2005-03-01 Kennametal Inc. Monolithic roof cutting bit insert
US20100326741A1 (en) * 2009-06-29 2010-12-30 Baker Hughes Incorporated Non-parallel face polycrystalline diamond cutter and drilling tools so equipped
US20110031036A1 (en) * 2009-08-07 2011-02-10 Baker Hughes Incorporated Superabrasive cutters with grooves on the cutting face, and drill bits and drilling tools so equipped
US8936659B2 (en) 2010-04-14 2015-01-20 Baker Hughes Incorporated Methods of forming diamond particles having organic compounds attached thereto and compositions thereof
US9140072B2 (en) 2013-02-28 2015-09-22 Baker Hughes Incorporated Cutting elements including non-planar interfaces, earth-boring tools including such cutting elements, and methods of forming cutting elements

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1718462A (en) * 1923-07-02 1929-06-25 Hardsocg Martin Rock drill
US1901643A (en) * 1928-05-08 1933-03-14 Reed Roller Bit Co Drill bit
GB423647A (en) * 1934-05-25 1935-02-05 Adolf Meutsch Improvements in stone boring tools, rock drills, and the like
US2306598A (en) * 1938-05-05 1942-12-29 Ray E Townsend Replaceable bit rock drill
FR951335A (en) * 1942-09-04 1949-10-21 Sandvikens Jernverks Ab Improvements to the processes and means used for rock drilling
US2494188A (en) * 1945-10-17 1950-01-10 Juan M Meaney Detachable rock drill bit with replaceable cutters
US2502128A (en) * 1948-04-30 1950-03-28 Joy Mfg Co Rock drill bit
US2507221A (en) * 1946-08-19 1950-05-09 Phipps Orville Single edge percussion bit
US2579268A (en) * 1946-12-27 1951-12-18 Malherbe Johannes Andrea Smuts Rock drill bit having hard inserts forming cutting edges
GB669636A (en) * 1947-07-04 1952-04-09 Louis Camille Andre Gardelle Improvements in or relating to rock drills

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1718462A (en) * 1923-07-02 1929-06-25 Hardsocg Martin Rock drill
US1901643A (en) * 1928-05-08 1933-03-14 Reed Roller Bit Co Drill bit
GB423647A (en) * 1934-05-25 1935-02-05 Adolf Meutsch Improvements in stone boring tools, rock drills, and the like
US2306598A (en) * 1938-05-05 1942-12-29 Ray E Townsend Replaceable bit rock drill
FR951335A (en) * 1942-09-04 1949-10-21 Sandvikens Jernverks Ab Improvements to the processes and means used for rock drilling
US2494188A (en) * 1945-10-17 1950-01-10 Juan M Meaney Detachable rock drill bit with replaceable cutters
US2507221A (en) * 1946-08-19 1950-05-09 Phipps Orville Single edge percussion bit
US2579268A (en) * 1946-12-27 1951-12-18 Malherbe Johannes Andrea Smuts Rock drill bit having hard inserts forming cutting edges
GB669636A (en) * 1947-07-04 1952-04-09 Louis Camille Andre Gardelle Improvements in or relating to rock drills
US2502128A (en) * 1948-04-30 1950-03-28 Joy Mfg Co Rock drill bit

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3006424A (en) * 1958-05-23 1961-10-31 Sandvikens Jernverks Ab Rock drill bits and cutting inserts therefor
US3096836A (en) * 1958-09-23 1963-07-09 Sandvikens Jernverks Ab Drill bits and cutting inserts therefor
US3080009A (en) * 1959-02-27 1963-03-05 Timken Roller Bearing Co Drill bit
US3059708A (en) * 1959-08-07 1962-10-23 Jersey Prod Res Co Abrasion resistant stepped blade rotary drill bit
US5429199A (en) * 1992-08-26 1995-07-04 Kennametal Inc. Cutting bit and cutting insert
US5829540A (en) * 1993-07-28 1998-11-03 Sandvik Rock Tools, Inc. Mine roof drill bit and cutting insert therefor
US5996715A (en) * 1993-07-28 1999-12-07 Sandvik Rock Tools, Inc. Mine roof drill bit and cutting insert therefor
US6595305B1 (en) 2000-02-15 2003-07-22 Kennametal Inc. Drill bit, hard member, and bit body
US6860344B2 (en) 2001-06-25 2005-03-01 Kennametal Inc. Monolithic roof cutting bit insert
US20100326741A1 (en) * 2009-06-29 2010-12-30 Baker Hughes Incorporated Non-parallel face polycrystalline diamond cutter and drilling tools so equipped
US8327955B2 (en) 2009-06-29 2012-12-11 Baker Hughes Incorporated Non-parallel face polycrystalline diamond cutter and drilling tools so equipped
US8851206B2 (en) 2009-06-29 2014-10-07 Baker Hughes Incorporated Oblique face polycrystalline diamond cutter and drilling tools so equipped
US9598909B2 (en) 2009-06-29 2017-03-21 Baker Hughes Incorporated Superabrasive cutters with grooves on the cutting face and drill bits and drilling tools so equipped
US20110031036A1 (en) * 2009-08-07 2011-02-10 Baker Hughes Incorporated Superabrasive cutters with grooves on the cutting face, and drill bits and drilling tools so equipped
US8739904B2 (en) * 2009-08-07 2014-06-03 Baker Hughes Incorporated Superabrasive cutters with grooves on the cutting face, and drill bits and drilling tools so equipped
US8936659B2 (en) 2010-04-14 2015-01-20 Baker Hughes Incorporated Methods of forming diamond particles having organic compounds attached thereto and compositions thereof
US9140072B2 (en) 2013-02-28 2015-09-22 Baker Hughes Incorporated Cutting elements including non-planar interfaces, earth-boring tools including such cutting elements, and methods of forming cutting elements

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