CA1253483A - Diamond drill bit with co-joined cutters - Google Patents
Diamond drill bit with co-joined cuttersInfo
- Publication number
- CA1253483A CA1253483A CA000515382A CA515382A CA1253483A CA 1253483 A CA1253483 A CA 1253483A CA 000515382 A CA000515382 A CA 000515382A CA 515382 A CA515382 A CA 515382A CA 1253483 A CA1253483 A CA 1253483A
- Authority
- CA
- Canada
- Prior art keywords
- bit
- face
- groupings
- joined
- cutters
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
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- Earth Drilling (AREA)
Abstract
ABSTRACT
An earth boring bit is shown having a body with one end which is connected to a drill string member for rotation and having an opposite end with a matrix formed thereon. A plurality of cutting elements are mounted on the matrix for dislodging geological formations. The cutting elements include groups of at least two but less than four cutters which are co-joined by a common backing of the matrix, the co-joined groups being spaced-apart from adjacent co-joined groups mounted on the matrix.
An earth boring bit is shown having a body with one end which is connected to a drill string member for rotation and having an opposite end with a matrix formed thereon. A plurality of cutting elements are mounted on the matrix for dislodging geological formations. The cutting elements include groups of at least two but less than four cutters which are co-joined by a common backing of the matrix, the co-joined groups being spaced-apart from adjacent co-joined groups mounted on the matrix.
Description
1~ 3 BACKGROUND OF THE INVENTION
3 1. Field of the Invention.
; This invention relates in general to earth boring 6 bits, particularly to those utilizing diamonds for 7 cutting elements used to disintegrate geological 8 formatiOns-
3 1. Field of the Invention.
; This invention relates in general to earth boring 6 bits, particularly to those utilizing diamonds for 7 cutting elements used to disintegrate geological 8 formatiOns-
2. Description of the Prior Art.
12 Commercially available earth boring bits can be 13 generally divided into the rolling cutter bits, having 14 either steel teeth or tungsten carbide inserts, and diamond bits, which utilize either natural diamonds or 16 artificial or man-made diamonds. The artificial diamonds 17 are "polycrystalline", used either individually or as a 18 component of a composite compact or insert on a cemented 19 tungsten carbide substrate. Recently, a new artificial, polycrystalline diamond has been developed which is 21 stable at higher temperatures than the previously known 22 polycrystalline diamond. Both types of polycrystalline 23 diamond are available in a wide variety of shapes and 24 sizes.
26 The diamond earth boring bits can be generally ~7 classified as either steel bodied bits or matrix bits.
28 The steel bodied bits are machined from a steel block and 29 typically have cutting elements which are press-fit into recesses provided in the bit face. The matrix bit is 31 formed by coating a hollow tubular steel mandrel in a 32 casting mold with metal bonded hard material, such as 33 tungsten carbide. The casting mold is of a configuration 34 which will give a bit of the desired form. The cutting elements are typically either polycrystalline diamond 36 compact cutters bra7ed within a recess provided in the ~2~3483 l matrix backlng or are thermally stable polycrystalline 2 diamond cutters which are cast wlthin recesses provided
12 Commercially available earth boring bits can be 13 generally divided into the rolling cutter bits, having 14 either steel teeth or tungsten carbide inserts, and diamond bits, which utilize either natural diamonds or 16 artificial or man-made diamonds. The artificial diamonds 17 are "polycrystalline", used either individually or as a 18 component of a composite compact or insert on a cemented 19 tungsten carbide substrate. Recently, a new artificial, polycrystalline diamond has been developed which is 21 stable at higher temperatures than the previously known 22 polycrystalline diamond. Both types of polycrystalline 23 diamond are available in a wide variety of shapes and 24 sizes.
26 The diamond earth boring bits can be generally ~7 classified as either steel bodied bits or matrix bits.
28 The steel bodied bits are machined from a steel block and 29 typically have cutting elements which are press-fit into recesses provided in the bit face. The matrix bit is 31 formed by coating a hollow tubular steel mandrel in a 32 casting mold with metal bonded hard material, such as 33 tungsten carbide. The casting mold is of a configuration 34 which will give a bit of the desired form. The cutting elements are typically either polycrystalline diamond 36 compact cutters bra7ed within a recess provided in the ~2~3483 l matrix backlng or are thermally stable polycrystalline 2 diamond cutters which are cast wlthin recesses provided
3 in the matrix backing.
Placement of the cutter elements on the bit face of 6 matrix bits has fallen into two general schemes. In the 7 first of these, the cutters are placed in a str`aight row 8 extending from a central location on ~he bit face out to 9 the full bit diameter. The performance of these bits is ' sometimes limited by the fact that cuttings dislodged at ll the center of the bit face must move in a straight line 12 down the cutting blade before exiting the bit face. There 13 is a tendency for cuttings to collect on the bit face and 14 restrict fluid flow across the bit face. In addition, cuttings from the bit center are reground along the 16 entire length of the blade, accelerating wear.
18 In the second scheme, cutters are set in individual l9 mountings placed strategically around the bit face.
~ These bits are disadvantaged by the fact that individual 21 cutter mounts are more susceptible to gross failure by 22 shearing.
~Z~i;3483 SUMMARY OF THE INVENTION
It is the general object of the invention to provide an earth boring drill bit with co-joined cutters mounted on the bit face so as to offer increased resistance to gross failure by shearing without interfering with the flow of fluid and entrained cuttings exiting the bit face.
Accordingly, an earth boring drill bit is provided having one end that includes means for connection to a drill string member, and having a matrix formed on the opposite end with a plurality of cutting elements mounted thereon. ~he cutting elements include groups of at least two but less than Pour cutters which are co-joined by a common backing of the matrix, the co-joined groups being spaced-apart from adjacent co-joined groups mounted on the matrix.
According to a broad aspect, the invention relates to an earth boring bit, comprising:
a body including a metallic shank on one end with a tubular bore and with means for connection to a drill string member and rotation about a longitudinal axis;
a cast matrix bonded to the metallic shank and forming a face of the bit, the bit face having a plurality of cutting elements mounted within backings of the matrix and extending radially on the bit face from a central location to an outermost gage portion, the cutting elements having cutting surfaces for dislodging geological formations;
at least one fluid opening communicating the bit face with the tubular bore of the bit for circulating fluids to the bit face; and wherein the cutting elements are arranged in groupings, the groupings including a plurality of cutter blades comprised of at least four cutters joined by a common backing, the cutter blades being mounted on the bit face adjacsnt the fluid opening and ext~nding 3~3 -3a-radially on the bit face from the central location in the direction of the gage portion but terminating short of the gage portion, the groupings on the bit face also being provided as pairs of cutters which are co-joined by a common backing of the matrix, the co-joined pairs being spaced-apart radially and circumferentially from adjacent co-joined pairs and from the cutter blades, the bit groupings on the bit face further being characterized in that none of the groupings extend from the central location completely to the outermost gage portion, so that fluid circulated through the fluid opening to the face of the bit can pass through the spaces defined between the groupings of cutterq in an unchanneled fashion.
The above as well as additional objects, features and advantages of the invention will become apparent in the following description.
Y~
r~
~Z~34~3 BRIEF DESCRIPTION OF THE DRAWINGS
3 Figure 1 is a perspective view as seen looking from
Placement of the cutter elements on the bit face of 6 matrix bits has fallen into two general schemes. In the 7 first of these, the cutters are placed in a str`aight row 8 extending from a central location on ~he bit face out to 9 the full bit diameter. The performance of these bits is ' sometimes limited by the fact that cuttings dislodged at ll the center of the bit face must move in a straight line 12 down the cutting blade before exiting the bit face. There 13 is a tendency for cuttings to collect on the bit face and 14 restrict fluid flow across the bit face. In addition, cuttings from the bit center are reground along the 16 entire length of the blade, accelerating wear.
18 In the second scheme, cutters are set in individual l9 mountings placed strategically around the bit face.
~ These bits are disadvantaged by the fact that individual 21 cutter mounts are more susceptible to gross failure by 22 shearing.
~Z~i;3483 SUMMARY OF THE INVENTION
It is the general object of the invention to provide an earth boring drill bit with co-joined cutters mounted on the bit face so as to offer increased resistance to gross failure by shearing without interfering with the flow of fluid and entrained cuttings exiting the bit face.
Accordingly, an earth boring drill bit is provided having one end that includes means for connection to a drill string member, and having a matrix formed on the opposite end with a plurality of cutting elements mounted thereon. ~he cutting elements include groups of at least two but less than Pour cutters which are co-joined by a common backing of the matrix, the co-joined groups being spaced-apart from adjacent co-joined groups mounted on the matrix.
According to a broad aspect, the invention relates to an earth boring bit, comprising:
a body including a metallic shank on one end with a tubular bore and with means for connection to a drill string member and rotation about a longitudinal axis;
a cast matrix bonded to the metallic shank and forming a face of the bit, the bit face having a plurality of cutting elements mounted within backings of the matrix and extending radially on the bit face from a central location to an outermost gage portion, the cutting elements having cutting surfaces for dislodging geological formations;
at least one fluid opening communicating the bit face with the tubular bore of the bit for circulating fluids to the bit face; and wherein the cutting elements are arranged in groupings, the groupings including a plurality of cutter blades comprised of at least four cutters joined by a common backing, the cutter blades being mounted on the bit face adjacsnt the fluid opening and ext~nding 3~3 -3a-radially on the bit face from the central location in the direction of the gage portion but terminating short of the gage portion, the groupings on the bit face also being provided as pairs of cutters which are co-joined by a common backing of the matrix, the co-joined pairs being spaced-apart radially and circumferentially from adjacent co-joined pairs and from the cutter blades, the bit groupings on the bit face further being characterized in that none of the groupings extend from the central location completely to the outermost gage portion, so that fluid circulated through the fluid opening to the face of the bit can pass through the spaces defined between the groupings of cutterq in an unchanneled fashion.
The above as well as additional objects, features and advantages of the invention will become apparent in the following description.
Y~
r~
~Z~34~3 BRIEF DESCRIPTION OF THE DRAWINGS
3 Figure 1 is a perspective view as seen looking from
4 the side of an earth boring bit embodying the principles S of my invention.
7 Figure 2 is a close-up, fragmentary side view of the 8 bit head, showing the preferred cutting elements.
lOFigure 3 is a head-on view of the bit face of the l earth boring bit of Fig. 1, showing the placement of the ~2 cutting elements thereon.
4Figure 4 is a simplified, side view of one type of cutting element mounted on the bit face.
-7Figure 5 is a side, isolated view of another type 8cutting element.
. 9 20Figure 6 is a simplified, side view of the cutting 21 element of Figure 5 mounted on the bit face.
~7 1 ~ESCRIPTION OF THE PREFE~ED EMBODIMENT
3The numeral 11 in the drawing designates an earth 4 boring bit having a body 13 with a threaded shank 15 formed on one end for connectLoll with a drill string 6 member (not shown~. The body 13 further includes a pair 7 of wrench flats 17 used to apply the appropriate torque 8 to properly "make-up" the threaded shank 15. The body 13 9 has a tubular bore 27 which communicates with the interior of the drill string member, and which 11 communicates by internal fluid passageways (not shown) '2 with one or more fluid openings 29 which are used to 13 circulate fluids to the bit face.
15On the opposite end of the bit body 13, there is 16 formed a bit head or "matrix" 19 in a predetermined 17 configuration to include cutting elements 21, 18 longitudinally extending lands 23, and fluid courses or 19 channels 25. The matrix 19 is of a composition of the ~ same type used in conventional diamond matrix bits, one 21 example being that which is disclosed in U.S. Pat. No.
~23,175,629 to David S. Rowley, issued March 30, 1965.
23 Such matrices can be, for example, formed of copper-24 nickel alloy containing powdered tungsten carbide.
~S
;~6Matrix head bits of the type under consideration are 27 manufactured by casting the matrix material in a mold 28 about a steel mandrel. The mold is first fabricated from ~9 graphite stock by turning on a lathe and machining a negative of the desired bit profile. Cutter pockets are 31 then milled in the interior of the mold to the proper 32 contours and dressed to define the position and angle of 33 the cutters. The fluid channels and internal fluid 34 passageways are formed by positioning a temporary displacement material within the interior of the mold 36 which will later be removed.
3~33 A steel mandrel is then inserted into the interior of the mold and the tungsten carbide powders, binders and flux are added to the mold. The steel mandrel acts as a ductile core to which the matrix material adheres during the casting and cooling stage. After firing the bit in a furnace, the mold is removed and the cutters are mounted on the exterior bit face within recesses in or receiving pockets of the matrix.
The bit head 19 in Fig. 1 has a ballistic or "bullet-shaped" profile which is generally conical in cross-section and which converges to a central nose location 31 on the bit face. The backings 33 for the cutting elements 21 are portions of the matrix which protrude outwardly from the face of the bit and which are formed with cutter receiving pocket~ or recesses 35 during the casting operation.
As shown in Fig. 4, the cutting elements 21 are of a hard material, preferably polycrystalline diamond composite compacts, referred to hereafter as PDC's. Such cutting elements are formed by sintering a polycrystalline diamond layer 22 to a tungsten carbide substrate 24 and are commercially available to the drilling industry from General ~lectric Company under the "STRATAPAX" trademark. The PDC i8 then preferably mounte~d in the recess 35 provided in the matrix 19 by brazing the PDC within the recess. The preferred cutting elements (21 in Figure 4) are generally cylindrical.
Figure 5 show6 another type of cutting element which can be mounted on the bit face. The cutting element 26 is formed by sintering a polycrystalline diamond layer 26 to a tungsten carbide substrate 28 which is bonded to a tungsten carbide stud 30 which i5 then preferably mounted into a recess (32 in Figure 6) provided in the matrix 19 ~53~183 1 by brazing, welding, cementing, or press fitting. U.S.
2 Pat. No. 4,539,018 to Whanger et al., lssued September 3, 3 1985, shows a method for manufacturing this type of stud q mounted cutter.
6The new thermally stable polycrystalline artificial 7 diamond useful as cutting elements in the invention are 8 currently being sold by General Electric Company under 9 the "GeoSet" trademark. These cutters are available in cylindrical ~ s and can be cast in place of the ll bit face in recesses similar to recess 35 in Fig. 4.
13As shown ln Figs. 1-3, the bit of the invention has 14cutting elements which include groups of at least two but 5less ~han rour cutters, such as the groups ~7 and 39 in 16Fig. 1, which are co-joined by a common backing 41, 43 of 17 the matrix. Preferably, the co-joined groups include 18 pairs of cutters which are co-joined by a common backing.
19 The distance between the cutters in a co-joined cutting group ranges from about 0.010 inches to a maximum of 21 about one half the diameter of one of the cutters in the 22 cutting group. The co-joined groups are themselves 23 spaced-apart from adjacent co-joined groups mounted on 24 the face of the bit to improve the flow of fluid and entrained cuttings exiting the bit face. The co-joined 26 groups radiate outwardly from the central location 31 27 generally along the bit face in the direction of the gage 28 portion 55.
30As shown in Fig. 3, the bit face can be provided 31with a plurality of cutter blades 45, 47, 49, 51, 53 32 comprised of at least four cutters joined by a common 33 backing. The cutter blades 45-53 are mounted on the bit 34 face adjacent the fluid openings 29 and extend radially on the bit face from the central location 31 in the 36 direction of the bit gage portion 55. The cutter blades 3~1~3 1 45-53 do not extend the entire distance to the gage 2 portion 55, however. The pairs of co-jolned cutters are 3 located in the region of the bit face between the cutter 4 blades ~5-53 and the gage portion 55. The co-joined pairs, 1.e. pair 38 in Fig. 2, are spaced-apart from 6 adjacent co-joined pairs, i.e. pair 40, and from the 7 cutter blades.
9 The use of co-joined cutters which share a common backlng of the matrix provides several advantages. The ll co-joined cutters improve the strength of the cutting 12 elements and resist shearing. Because traditional full-13 length blades are not utilized, cuttings can swirl across 14 the bit face without causing a build-up or forming a dam.
Improved fluid flow over the bit face is achieved without 16 decreasing the resistance of the cutting elements to 17 shearing and failure.
19 While the invention has been shown ln only one of its forms, it is not thus limited but is susceptible to 21 various changes and modifications without departing from 22 the spirit thereof.
7 Figure 2 is a close-up, fragmentary side view of the 8 bit head, showing the preferred cutting elements.
lOFigure 3 is a head-on view of the bit face of the l earth boring bit of Fig. 1, showing the placement of the ~2 cutting elements thereon.
4Figure 4 is a simplified, side view of one type of cutting element mounted on the bit face.
-7Figure 5 is a side, isolated view of another type 8cutting element.
. 9 20Figure 6 is a simplified, side view of the cutting 21 element of Figure 5 mounted on the bit face.
~7 1 ~ESCRIPTION OF THE PREFE~ED EMBODIMENT
3The numeral 11 in the drawing designates an earth 4 boring bit having a body 13 with a threaded shank 15 formed on one end for connectLoll with a drill string 6 member (not shown~. The body 13 further includes a pair 7 of wrench flats 17 used to apply the appropriate torque 8 to properly "make-up" the threaded shank 15. The body 13 9 has a tubular bore 27 which communicates with the interior of the drill string member, and which 11 communicates by internal fluid passageways (not shown) '2 with one or more fluid openings 29 which are used to 13 circulate fluids to the bit face.
15On the opposite end of the bit body 13, there is 16 formed a bit head or "matrix" 19 in a predetermined 17 configuration to include cutting elements 21, 18 longitudinally extending lands 23, and fluid courses or 19 channels 25. The matrix 19 is of a composition of the ~ same type used in conventional diamond matrix bits, one 21 example being that which is disclosed in U.S. Pat. No.
~23,175,629 to David S. Rowley, issued March 30, 1965.
23 Such matrices can be, for example, formed of copper-24 nickel alloy containing powdered tungsten carbide.
~S
;~6Matrix head bits of the type under consideration are 27 manufactured by casting the matrix material in a mold 28 about a steel mandrel. The mold is first fabricated from ~9 graphite stock by turning on a lathe and machining a negative of the desired bit profile. Cutter pockets are 31 then milled in the interior of the mold to the proper 32 contours and dressed to define the position and angle of 33 the cutters. The fluid channels and internal fluid 34 passageways are formed by positioning a temporary displacement material within the interior of the mold 36 which will later be removed.
3~33 A steel mandrel is then inserted into the interior of the mold and the tungsten carbide powders, binders and flux are added to the mold. The steel mandrel acts as a ductile core to which the matrix material adheres during the casting and cooling stage. After firing the bit in a furnace, the mold is removed and the cutters are mounted on the exterior bit face within recesses in or receiving pockets of the matrix.
The bit head 19 in Fig. 1 has a ballistic or "bullet-shaped" profile which is generally conical in cross-section and which converges to a central nose location 31 on the bit face. The backings 33 for the cutting elements 21 are portions of the matrix which protrude outwardly from the face of the bit and which are formed with cutter receiving pocket~ or recesses 35 during the casting operation.
As shown in Fig. 4, the cutting elements 21 are of a hard material, preferably polycrystalline diamond composite compacts, referred to hereafter as PDC's. Such cutting elements are formed by sintering a polycrystalline diamond layer 22 to a tungsten carbide substrate 24 and are commercially available to the drilling industry from General ~lectric Company under the "STRATAPAX" trademark. The PDC i8 then preferably mounte~d in the recess 35 provided in the matrix 19 by brazing the PDC within the recess. The preferred cutting elements (21 in Figure 4) are generally cylindrical.
Figure 5 show6 another type of cutting element which can be mounted on the bit face. The cutting element 26 is formed by sintering a polycrystalline diamond layer 26 to a tungsten carbide substrate 28 which is bonded to a tungsten carbide stud 30 which i5 then preferably mounted into a recess (32 in Figure 6) provided in the matrix 19 ~53~183 1 by brazing, welding, cementing, or press fitting. U.S.
2 Pat. No. 4,539,018 to Whanger et al., lssued September 3, 3 1985, shows a method for manufacturing this type of stud q mounted cutter.
6The new thermally stable polycrystalline artificial 7 diamond useful as cutting elements in the invention are 8 currently being sold by General Electric Company under 9 the "GeoSet" trademark. These cutters are available in cylindrical ~ s and can be cast in place of the ll bit face in recesses similar to recess 35 in Fig. 4.
13As shown ln Figs. 1-3, the bit of the invention has 14cutting elements which include groups of at least two but 5less ~han rour cutters, such as the groups ~7 and 39 in 16Fig. 1, which are co-joined by a common backing 41, 43 of 17 the matrix. Preferably, the co-joined groups include 18 pairs of cutters which are co-joined by a common backing.
19 The distance between the cutters in a co-joined cutting group ranges from about 0.010 inches to a maximum of 21 about one half the diameter of one of the cutters in the 22 cutting group. The co-joined groups are themselves 23 spaced-apart from adjacent co-joined groups mounted on 24 the face of the bit to improve the flow of fluid and entrained cuttings exiting the bit face. The co-joined 26 groups radiate outwardly from the central location 31 27 generally along the bit face in the direction of the gage 28 portion 55.
30As shown in Fig. 3, the bit face can be provided 31with a plurality of cutter blades 45, 47, 49, 51, 53 32 comprised of at least four cutters joined by a common 33 backing. The cutter blades 45-53 are mounted on the bit 34 face adjacent the fluid openings 29 and extend radially on the bit face from the central location 31 in the 36 direction of the bit gage portion 55. The cutter blades 3~1~3 1 45-53 do not extend the entire distance to the gage 2 portion 55, however. The pairs of co-jolned cutters are 3 located in the region of the bit face between the cutter 4 blades ~5-53 and the gage portion 55. The co-joined pairs, 1.e. pair 38 in Fig. 2, are spaced-apart from 6 adjacent co-joined pairs, i.e. pair 40, and from the 7 cutter blades.
9 The use of co-joined cutters which share a common backlng of the matrix provides several advantages. The ll co-joined cutters improve the strength of the cutting 12 elements and resist shearing. Because traditional full-13 length blades are not utilized, cuttings can swirl across 14 the bit face without causing a build-up or forming a dam.
Improved fluid flow over the bit face is achieved without 16 decreasing the resistance of the cutting elements to 17 shearing and failure.
19 While the invention has been shown ln only one of its forms, it is not thus limited but is susceptible to 21 various changes and modifications without departing from 22 the spirit thereof.
Claims (2)
1. An earth boring bit, comprising:
a body including a metallic shank on one end with a tubular bore and with means for connection to a drill string member and rotation about a longitudinal axis;
a cast matrix bonded to the metallic shank and forming a face of the bit, the bit face having a plurality of cutting elements mounted within backings of the matrix and extending radially on the bit face from a central location to an outermost gage portion, the cutting elements having cutting surfaces for dislodging geological formations;
at least one fluid opening communicating the bit face with the tubular bore of the bit for circulating fluids to the bit face; and wherein the cutting elements are arranged in groupings, the groupings including a plurality of cutter blades comprised of at least four cutters joined by a common backing, the cutter blades being mounted on the bit face adjacent the fluid opening and extending radially on the bit face from the central location in the direction of the gage portion but terminating short of the gage portion, the groupings on the bit face also being provided as pairs of cutters which are co-joined by a common backing of the matrix, the co-joined pairs being spaced-apart radially and circumferentially from adjacent co-joined pairs and from the cutter blades, the bit groupings on the bit face further being characterized in that none of the groupings extend from the central location completely to the outermost gage portion, so that fluid circulated through the fluid opening to the face of the bit can pass through the spaces defined between the groupings of cutters in an unchanneled fashion.
a body including a metallic shank on one end with a tubular bore and with means for connection to a drill string member and rotation about a longitudinal axis;
a cast matrix bonded to the metallic shank and forming a face of the bit, the bit face having a plurality of cutting elements mounted within backings of the matrix and extending radially on the bit face from a central location to an outermost gage portion, the cutting elements having cutting surfaces for dislodging geological formations;
at least one fluid opening communicating the bit face with the tubular bore of the bit for circulating fluids to the bit face; and wherein the cutting elements are arranged in groupings, the groupings including a plurality of cutter blades comprised of at least four cutters joined by a common backing, the cutter blades being mounted on the bit face adjacent the fluid opening and extending radially on the bit face from the central location in the direction of the gage portion but terminating short of the gage portion, the groupings on the bit face also being provided as pairs of cutters which are co-joined by a common backing of the matrix, the co-joined pairs being spaced-apart radially and circumferentially from adjacent co-joined pairs and from the cutter blades, the bit groupings on the bit face further being characterized in that none of the groupings extend from the central location completely to the outermost gage portion, so that fluid circulated through the fluid opening to the face of the bit can pass through the spaces defined between the groupings of cutters in an unchanneled fashion.
2. An earth boring bit which reduces the regrinding of abrasive cuttings during drilling, comprising:
a body including a metallic shank on one end with a tubular bore and with means for connection to a drill string member and rotation about a longitudinal axis;
a cast matrix bonded to the metallic shank and forming a ballistic, conical-shaped face of the bit, the bit face having a plurality of cutting elements mounted within backings of the matrix which protrude outwardly from the face of the bit and which extend substantially radially on the bit face from a central location to an outermost gage portion, the cutting elements having cutting surfaces for dislodging geological formations;
at least one fluid opening communicating the bit face with the tubular bore of the bit for circulating fluids to the bit face; and wherein the cutting elements are arranged in groupings, the groupings including a plurality of cutter blades none of which include more than four cutters joined by a common backing, the cutter blades being mounted on the bit face adjacent the fluid opening and extending radially on the bit face from the central location in the direction of the gage portion but terminating short of the gage portion, the groupings on the bit face also being provided as pairs of cutters which are co-joined by a common backing of the matrix, the co-joined pairs being spaced-apart radially and circumferentially from adjacent co-joined pairs and from the cutter blades, the bit groupings on the bit face further being characterized in that none of the groupings extend from the central location completely to the outermost gage portion, so that fluid circulated through the fluid opening to the face of the bit can pass through the spaces defined between the groupings of cutters and travel in unchanneled fashion in the direction of the gage portion.
a body including a metallic shank on one end with a tubular bore and with means for connection to a drill string member and rotation about a longitudinal axis;
a cast matrix bonded to the metallic shank and forming a ballistic, conical-shaped face of the bit, the bit face having a plurality of cutting elements mounted within backings of the matrix which protrude outwardly from the face of the bit and which extend substantially radially on the bit face from a central location to an outermost gage portion, the cutting elements having cutting surfaces for dislodging geological formations;
at least one fluid opening communicating the bit face with the tubular bore of the bit for circulating fluids to the bit face; and wherein the cutting elements are arranged in groupings, the groupings including a plurality of cutter blades none of which include more than four cutters joined by a common backing, the cutter blades being mounted on the bit face adjacent the fluid opening and extending radially on the bit face from the central location in the direction of the gage portion but terminating short of the gage portion, the groupings on the bit face also being provided as pairs of cutters which are co-joined by a common backing of the matrix, the co-joined pairs being spaced-apart radially and circumferentially from adjacent co-joined pairs and from the cutter blades, the bit groupings on the bit face further being characterized in that none of the groupings extend from the central location completely to the outermost gage portion, so that fluid circulated through the fluid opening to the face of the bit can pass through the spaces defined between the groupings of cutters and travel in unchanneled fashion in the direction of the gage portion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US82370686A | 1986-01-29 | 1986-01-29 | |
| US823,706 | 1986-01-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1253483A true CA1253483A (en) | 1989-05-02 |
Family
ID=25239485
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000515382A Expired CA1253483A (en) | 1986-01-29 | 1986-08-06 | Diamond drill bit with co-joined cutters |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1253483A (en) |
-
1986
- 1986-08-06 CA CA000515382A patent/CA1253483A/en not_active Expired
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