DRILL BIT

Abstract

A drill bit (26), the drill bit (26) comprising: a substantially tubular bit body (30) defining a body proximal end (32) and a substantially longitudinally opposed body distal end (34); a crown (38) extending from the bit body (30) at the body distal end (34), the crown (38) having a generally annular configuration defining crown inner and outer diameters (48 and 50); the crown (38) including a plurality of segments (46) provided between the crown inner and outer diameters (48 and 50), at least one of the segments (46) extending only partially radially across the crown (38) between the crown inner and outer diameters (48 and 50).

Description

FIELD OF THE INVENTION

The present invention relates to the general field of drilling, and is particularly concerned with a drill bit.

BACKGROUND

In the geological exploration, mining and construction industries, among others, drill bits 10, an example of which is shown in FIG. 1, are used to drill through rock, concrete and other materials. Typically, as seen in FIG. 1, the drill bit 10 includes a bit body 12 and a crown 14 extending substantially longitudinally from the bit body 12. Slots 16 are formed into the crown 14 and define drilling segments 18. The crown 14 is the portion of the drill bit 10 that cuts or erodes the material through which a bore is drilled. The bit body 12 and the crown 14 define a central passageway 20 through which water (not shown in FIG. 1) is injected. The slots 16 allow water and debris (not shown in the drawings) to flow out of the central passageway 20.

By design, there are only limited variations in the parameters defining the drilling segments 18, such as distance between drilling segments 18, or width of the slots 16, and the number of drilling segments 18. Also, typically, the drilling segments 18 are relatively large. These limitations limit the heat dissipation and debris clearance characteristics of the drill bit 10.

Against this background, there exists a need in the industry to provide an improved drill bit. An object of the present invention is therefore to provide an improved drill bit.

SUMMARY OF THE INVENTION

In a broad aspect, the invention provides a drill bit, the drill bit comprising: a substantially tubular bit body defining a body proximal end and a substantially longitudinally opposed body distal end; a crown extending from the bit body at the body distal end, the crown having a generally annular configuration defining crown inner and outer diameters; the crown including a plurality of segments provided between the crown inner and outer diameters, at least one of the segments extending only partially radially across the crown between the crown inner and outer diameters.

Advantageously, the proposed drill bit allows for more variations in mechanical and hydrodynamic properties of the crown than conventional drill bits, which allows adapting the drill bit to different drilling conditions. In some embodiments, this allows for an improvement in cooling and debris evacuation characteristics of the drill bits when compared to conventional drill bits.

Also, the proposed drill bit is relatively easily manufacturable using known methods and materials.

In some embodiments of the invention, each of the segments extends only partially radially across the crown between the crown inner and outer diameters.

In some embodiments of the invention, the segments are divided in inner segments and outer segments, the outer segments all extending radially outwardly further than the inner segments and the inner segments all extending radially inwardly further than the outer segments, the segments alternating circumferentially between outer segments and inner segments. In a variant, the inner and outer segments overlap circumferentially. In another variant, the inner and outer segments are circumferentially spaced apart from each other so as to have no circumferential overlap therebetween.

In some embodiments of the invention, all virtual circles contained in and concentric with the crown intersect at least one of the segments.

In some embodiments of the invention, the crown defines a plurality of waterways devoid of the segments, each waterway extending between the crown inner and outer diameters. For example, the waterways are substantially equidistantly spaced apart from one another circumferentially around the crown.

In some embodiments of the invention, the segments define segment groups circumferentially spaced apart from each other by the waterways, each segment group including at least two of the segments.

In some embodiments of the invention, each segment of each segment group is closer to at least one other segment from the same segment group than to all of the segments outside of the same segment group.

In some embodiments of the invention, at least two segments from at least one of the segment groups contact each other.

In some embodiments of the invention, the segment groups each extend from the crown inner diameter to the crown outer diameter.

In some embodiments of the invention, the bit body defines a plurality of segment receiving recesses extending thereinto at the body distal end and the segments each define a segment attachment portion inserted in one of the segment receiving recesses and a segment abrading portion provided outside of the segment receiving recesses. For example, the segment attachment portions and the segment receiving recesses are threaded and the segment attachment portions are screwed in the segment receiving recesses. In other examples, the segments are glued, soldered or brazed to the bit body, sometimes in combination with being screwed thereto.

In some embodiments of the invention, at least some of the segments have a substantially constant transversal configuration longitudinally therealong.

In some embodiments of the invention, at least one of the segments has at least a portion thereof tapering in a direction leading towards the bit body.

In some embodiments of the invention, at least one of the segments has at least a portion thereof tapering in a direction leading away from the bit body.

In some embodiments of the invention, at least one of the segments has a substantially circular transversal cross-sectional configuration.

In some embodiments of the invention, at least one of the segments has a substantially triangular transversal cross-sectional configuration.

In some embodiments of the invention, at least one of the segments has a substantially trapezoidal transversal cross-sectional configuration.

In some embodiments of the invention, the crown protrudes radially inwardly and outwardly relative to the bit body.

In some embodiments of the invention, the segments each include abrasive particles contained in a metal matrix. For example, the abrasive particles include diamond particles.

In some embodiments of the invention, the drill bit defines a drill string attachment substantially adjacent the body proximal end, the drill string attachment being configured and sized for attaching the drill bit to a drill string. For example, the drill string attachment includes threads for screwing the drill bit to the drill string.

In some embodiments of the invention, the segments are all in a spaced apart relationship relative to each other.

In another broad aspect, the invention provides a drill bit usable with a fluid, the drill bit comprising: a bit body, the bit body defining a body proximal end and a substantially longitudinally opposed body distal end, the bit body defining a body passageway extending substantially longitudinally therethrough for receiving the fluid and conveying the fluid through the bit body; a substantially annular crown extending substantially longitudinally from the bit body, the crown defining a crown distal end and a substantially longitudinally opposed crown proximal end, the crown extending from the bit body with the crown proximal end located substantially adjacent to the body distal end, the crown defining a crown passageway extending substantially longitudinally therethrough, the crown passageway being in fluid communication with the body passageway for receiving the fluid from the body passageway, the crown extending between a crown inner diameter and a crown outer diameter; the crown including a plurality of segments, each of the segments extending only partially circumferentially and radially across the crown.

All embodiments and examples mentioned hereinabove also apply to the drill bit described in the preceding paragraph.

Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the appended drawings:

FIG. 1, already described, in a perspective view, illustrates a prior art drill bit;

FIG. 2, in a perspective view, illustrates a drill bit in accordance with an embodiment of the present invention;

FIG. 3, in a top plan view, illustrates the drill bit shown in FIG. 2;

FIG. 4A, in a top plan view, illustrate a drill bit in accordance with an alternative embodiment of the invention;

FIG. 4B in a perspective view, illustrate the drill bit shown in FIG. 4A;

FIG. 4C in a top plan view, illustrate a drill bit in accordance with another alternative embodiment of the invention;

FIG. 4D in a perspective view, illustrate the drill bit shown in FIG. 4C; and

FIG. 5, in a perspective exploded view, illustrates part of a drill bit illustrating features of yet other alternative embodiments of the invention.

DETAILED DESCRIPTION

Referring to FIG. 2, there is shown a drill bit 26 usable with a fluid (not shown in the drawings). Typically the fluid includes water to which additives may have been added. The drill bit 26 includes a substantially tubular bit body 30 and a crown 38. The drill bit 26 is typically used to drill cores in rock or other materials. However, other uses of the drill bit 26 are within the scope of the invention.

For the purpose of this document, the terminology proximal and distal refers to a distance from an operator located on the surface who operates the drill bit 26 down a bore hole. Therefore, distal elements are provided lower in the bore hole, or further away from the operator, than proximal elements. This terminology is used to facilitate the description of the drill bit 26 and should not be used to restrict the scope of the present invention.

The present document also uses directional terminology such as “longitudinal”, “radial”, “circumferential” and their adverbs. This terminology is relative to the general cylindrical configuration of the drill bit 26. Also, the terminology “transversal” is used to denote a plane perpendicular to the general longitudinal direction.

Also, the terminology “substantially” is used to denote variations in the thus qualified terms that have no significant effect on the principle of operation of the drill bit 26. These variations may be minor variations in design or variations due to mechanical tolerances in manufacturing and use of the drill bit 26. These variations are to be seen with the eye of the reader skilled in the art.

The bit body 30 defines a body proximal end 32 and a substantially longitudinally opposed body distal end 34. The bit body 30 also defined a body distal surface 31 at the body distal end. For example, the body distal surface 31 is substantially annular and generally transversal. The bit body 30 further defines a body passageway 36 extending substantially longitudinally therethrough for receiving the fluid and conveying the fluid through the bit body 30. Typically, the drill bit 26 defines a drill string attachment 25 (only partially shown in FIG. 2) substantially adjacent the body proximal end 32. The drill string attachment 25 is configured and sized for attaching the drill bit 26 to a conventional drill string (not shown in the drawings). To that effect, for example, the drill string attachment 25 takes the form of threads formed inside the bit body 30 for screwing the drill bit 26 to the drill string.

The crown 38 extends from the bit body 26 at the body distal end 34. The crown 38 has a generally annular configuration defining crown inner and outer diameters 48 and 50 (as better seen in FIG. 3). The general annular configuration of the crown 38 does not imply that the crown is a solid element of annular configuration, but that the various elements forming the crown 38 are contained in a volume that has a generally annular shape. The crown 38 includes a plurality of segments 46 provided between the crown inner and outer diameters 48 and 50, at least one of the segments 46 extending only partially radially across the crown 38 between the crown inner and outer diameters 48 and 50. The crown inner and outer diameters are the diameters of the smallest and largest circles concentric to the crown 38 that intersect at least one of the segments 46. Typically, each of the segments 46 extends only partially radially across the crown 38 between the crown inner and outer diameters 48 and 50. This is to be contrasted to conventional drill bits, such as the previously described drill bit 10 shown in FIG. 1, in which all the segments 18 extend radially between the crown inner and outer diameter.

The segments 46 are elements of the crown 38 that may or may not contact other segments 46, but that are physically distinct entities which do not extend integrally from each other. The segments 46 form the portion of the drill bit 10 that removes the rock or other materials from the bore to be created with the drill bit 10. In some embodiments of the invention, all the segments 46 extend either to the crown inner diameter 48 or to the crown outer diameter 50. In these embodiments, all the segments 46, in addition to cutting or eroding the material in which the drill bit 10 is used, also maintain either the diameter of the bore hole that is created or the diameter of the central portion of the material that is received in the drill bit 10. This central portion often forms a core that is retrieved for further analysis. Also, in some embodiments of the invention, all the segments 46 are non-contacting and separated from each other by a gap. In other words, in these embodiments, the segments 46 are all in a spaced apart relationship relative to each other.

Returning to FIG. 2, the crown 38 defines a crown distal end 40 and a substantially opposed crown proximal end 42. The crown 38 extends from the bit body 30 with the crown proximal end 42 located substantially adjacent to the body distal end 34. The crown 38 defines a crown passageway 44 extending substantially longitudinally therethrough, the crown passageway 44 being in fluid communication with the body passageway 36 for receiving the fluid from the body passageway 36. Typically, but not necessarily, the segments 46 extend proximally further than the crown proximal end 42 to allow attachment of the segments 46 to the bit body 30, as detailed hereinbelow.

In opposition to some drill bits that include cutting disks or inserts, in some embodiments of the invention, the segments 46 are configured and sized such that every circumference of the crown 38 between the crown inner and outer diameters 48 and 50 intersect at least one segment 46. In other words, all virtual circles contained in and concentric with the crown 38 intersect at least one of the segments 46. Also, in some embodiments of the invention, the segments 46 are used both to create a longitudinally constant diameter of the bore hole and of the core and to remove rock and other ground material from the bottom of the bore hole. To that effect, the crown 38 protrudes radially inwardly and outwardly relative to the bit body 30.

Typically, the crown 38 defines a plurality of waterways 47 (better seen in FIG. 3) devoid of the segments 46. Each waterway 47 extends between the crown inner and outer diameters 48 and 50. The waterways 47 can be substantially radially extending in a substantially rectilinear manner, as seen in FIG. 3, or can also be oriented partially along the circumference of the crown 38. The waterways 47 can have any suitable shape and can taper in either a direction leading radially inwardly or radially outwardly, or show no such taper. In some embodiments of the invention, the waterways 47 are substantially equidistantly spaced apart from one another circumferentially around the crown 38.

Referring to FIG. 3, in some embodiments of the invention, the segments 46 define segment groups 52. The segment groups 52 are circumferentially spaced apart from each other by the waterways 47 and each segment group 52 includes at least two of the segments 46. Typically, each segment 46 of each segment group 52 is closer to at least one other segment 46 from the same segment group 52 than to all of the segments 46 outside of the same segment group 52. Segment groups 52 are therefore in these embodiments subsets of the segments 46 that are closer to each other than they are to other segment groups 52.

In some embodiments of the invention, some or all of the segments 46 from each of the segment groups 52 contact at least one other segment 46 from the same segment group. However, in other embodiments, the segments 46 are all spaced apart from each other in the segment group 52.

In some embodiments of the invention, each segment group 52 extends the entire radial extension of the crown 38. In other words, in these embodiments, the segment groups 52 each extend from the crown inner diameter 48 to the crown outer diameter 50 so that in each segment group 52, there is at least one segment 46 that reaches the crown inner diameter 48 and at least another segment 46 that reaches the crown outer diameter 50. Within each segment group 52, there is an intra-group gap 54 between the segments 46. Inter-group gaps 56 extend between the segment groups 52, the inter-group gaps defining the waterways 47.

The bit body 30 is typically made out of a metal, such as steel, while the segments 46 each include abrasive particles contained in a metal matrix. For example, the abrasive particles include diamond particles and the segments 46 include diamond-encrusted matrices of conventional composition that are relatively abrasive, robust and wear resistant.

In some embodiments of the invention, each segment 46 is individually selectively attachable to the bit body 30. This attachment can be made in the field, just prior to use of the drill bit 26, or during the manufacturing process. This provides great flexibility in having a drill bit 26 suitable for a particular drilling situation. For example, referring to FIG. 2, the bit body 30 defines segment receiving recesses 58 extending thereinto at the body distal end 34. Typically, the segment receiving recesses 58 extend substantially longitudinally in the bit body 30 from the bit distal surface 31, but this is not necessarily the case in all embodiments as the segment receiving recesses 58 may extend from other surfaces of the bit body 30 and/or extend obliquely relative to the bit body 30. Each segment receiving recess 58 receives a respective segment 46 thereinto. More specifically, each segment 46 defines a segment attachment portion 57 inserted in one of the segment receiving recesses 58 and a segment abrading portion 59 provided outside of the segment receiving recesses 58. However, in other embodiments, the segments 46 are molded together as a single unit in a conventional manner.

In a variant, as seen for example in FIG. 5, the segment receiving recesses 58A and the segments 46A, and more specifically the segment attachment portion 57A thereof, are threaded and the segment attachment portions 57A are simply screwed in the segment receiving recesses 58A. In another variant, also seen in FIG. 5, the segments 46B, and more specifically the segment attachment portions thereof 57B, are slidably inserted in the segment receiving recesses 58B and soldered, glued or brazed to the bit body 30. It is also possible to have segments 46A that are both screwed in the segment receiving recesses 58A and either soldered, glued or brazed to the bit body 30. It should be noted that FIG. 5 illustrates two types of segment attachment portions 57A and 57B and two corresponding types of segment receiving recesses 58A and 58B in the same Figure to better illustrate these two variants. While it is possible to mix these two types of segment attachment portions 57A and 57B and segment receiving recesses 58A and 58B in a single device, in a typical embodiment only one type is used.

Various shapes and configurations are possible for the segments 46 and segment groups 52. For example, as seen in FIG. 2, the segments 46 can have a constant transversal configuration longitudinally therealong. Now referring to FIG. 5, in other embodiments, as in segment 46A, the segment 46A has at least a portion thereof, for example the segment abrading portion 59A, that tapers in a direction leading away from the bit body 30. In yet other embodiments, as in segment 46B, the segment 46B has at least a portion thereof, for example the segment abrading portion 59B, that tapers in a direction leading towards the bit body 30.

In some embodiments of the invention, as seen in FIGS. 2 and 3, the segments 46 have a substantially cylindrical configuration and therefore have a circular transversal cross-sectional configuration. In alternative embodiments, such as in the drill bits 26C and 26D shown respectively in FIGS. 4A and 4C, the segments 46C, 46CC, 46D and 46DD have respectively substantially triangular (for segments 46C and 46CC) or substantially trapezoidal (for segments 46D and 46DD) transversal cross-sectional configurations.

Also, in some embodiments, as seen in FIGS. 4A to 4D, the segments 46C, 46CC, 46D and 46DD are divided between outer segments 46CC and 46DD and inner segments 46C and 46D. Inner and outer segments 46C and 46CC are shown in FIGS. 4A and 4B while inner and outer segments 46D and 46DD are shown in FIGS. 4C and 4D. For each drill bit 26C and 26D, the outer segments 46CC and 46DD all extend radially outwardly further than the inner segments 46C and 46D and the inner segments 46C and 46D all extend radially inwardly further than the outer segments 46CC and 46DD.

The segments 46C, 46CC, 46D and 46DD alternate circumferentially between outer segments 46CC and 46DD and inner segments 46C and 46D. Typically, the outer segments 46CC and 46DD extend from the crown outer diameter 50 towards the crown inner diameter 48 without reaching the latter and the inner segments 46C and 46D extend from the crown inner diameter 48 towards the crown outer diameter 50 without reaching the latter. As seen in FIG. 4A, in some embodiments, the inner and outer segments 46C and 46CC overlap circumferentially such that at least some radii of the drill bit 26C intersect both one of the outer segments 46CC and one of the inner segments 46C. However, in alternative embodiments, as seen in FIG. 4C, the inner and outer segments 46D and 46DD can be circumferentially spaced part so as to have no circumferential overlap therebetween. In these embodiments, no radius of the drill bit 26D intersect both one of the outer segments 46DD and one of the inner segments 46D.

In some embodiments of the invention, the segments 46 do not all have identical transversal cross-sectional configurations. In yet other embodiments of the invention, the segments 46 have transversal cross-sectional configurations that vary longitudinally therealong. Typically, but not necessarily, the segments 46 have a larger longitudinal dimensions than transversal dimensions.

Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified, without departing from the spirit and nature of the subject invention as defined in the appended claims.

Claims

1. A drill bit, said drill bit comprising: a substantially tubular bit body defining a body proximal end and a substantially longitudinally opposed body distal end;a crown extending from said bit body at said body distal end, said crown having a generally annular configuration defining crown inner and outer diameters;said crown including a plurality of segments provided between said crown inner and outer diameters, at least one of said segments extending only partially radially across said crown between said crown inner and outer diameters.

2. A drill bit as defined in claim 1, wherein each of said segments extends only partially radially across said crown between said crown inner and outer diameters.

3. A drill bit as defined in claim 2, wherein said segments are divided in inner segments and outer segments, said outer segments all extending radially outwardly further than said inner segments and said inner segments all extending radially inwardly further than said outer segments, said segments alternating circumferentially between outer segments and inner segments.

4. A drill bit as defined in claim 3, wherein said inner and outer segments overlap circumferentially.

5. A drill bit as defined in claim 3, wherein said inner and outer segments are circumferentially spaced apart from each other so as to have no circumferential overlap therebetween.

6. A drill bit as defined in claim 1, wherein all virtual circles contained in and concentric with said crown intersect at least one of said segments.

7. A drill bit as defined in claim 1, wherein said crown defines a plurality of waterways devoid of said segments, each waterway extending between said crown inner and outer diameters.

8. A drill bit as defined in claim 7, wherein said waterways are substantially equidistantly spaced apart from one another circumferentially around said crown.

9. A drill bit as defined in claim 7, wherein said segments define segment groups circumferentially spaced apart from each other by said waterways, each segment group including at least two of said segments.

10. A drill bit as defined in claim 9, wherein each segment of each segment group is closer to at least one other segment from the same segment group than to all of said segments outside of said same segment group.

11. A drill bit as defined in claim 9, wherein at least two segments from at least one of said segment groups contact each other.

12. A drill bit as defined in claim 9, wherein said segment groups each extend from said crown inner diameter to said crown outer diameter.

13. A drill bit as defined in claim 1, wherein said bit body defines a plurality of segment receiving recesses extending thereinto at said body distal end and said segments each define a segment attachment portion inserted in one of said segment receiving recesses and a segment abrading portion provided outside of said segment receiving recesses.

14. A drill bit as defined in claim 13, wherein said segment attachment portions and said segment receiving recesses are threaded and said segment attachment portions are screwed in said segment receiving recesses.

15. A drill bit as defined in claim 13, wherein said segments are glued to said bit body.

16. A drill bit as defined in claim 13, wherein said segments are soldered to said bit body.

17. A drill bit as defined in claim 13, wherein said segments are brazed to said bit body.

18. A drill bit as defined in claim 1, wherein at least some of said segments have a substantially constant transversal configuration longitudinally therealong.

19. A drill bit as defined in claim 1, wherein at least one of said segments has at least a portion thereof tapering in a direction leading towards said bit body.

20. A drill bit as defined in claim 1, wherein at least one of said segments has at least a portion thereof tapering in a direction leading away from said bit body.

21. A drill bit as defined in claim 1, wherein at least one of said segments has a substantially circular transversal cross-sectional configuration.

22. A drill bit as defined in claim 1, wherein at least one of said segments has a substantially triangular transversal cross-sectional configuration.

23. A drill bit as defined in claim 1, wherein at least one of said segments has a substantially trapezoidal transversal cross-sectional configuration.

24. A drill bit as defined in claim 1, wherein said crown protrudes radially inwardly and outwardly relative to said bit body.

25. A drill bit as defined in claim 1, wherein said segments each include abrasive particles contained in a metal matrix.

26. A drill bit as defined in claim 25, wherein said abrasive particles include diamond particles.

27. A drill bit as defined in claim 1, wherein said drill bit defines a drill string attachment substantially adjacent said body proximal end, said drill string attachment being configured and sized for attaching said drill bit to a drill string.

28. A drill bit as defined in claim 27, wherein said drill string attachment includes threads for screwing said drill bit to said drill string.

29. A drill bit as defined in claim 1, wherein said segments are all in a spaced apart relationship relative to each other.

30. A drill bit usable with a fluid, said drill bit comprising: a bit body, said bit body defining a body proximal end and a substantially longitudinally opposed body distal end, said bit body defining a body passageway extending substantially longitudinally therethrough for receiving said fluid and conveying said fluid through said bit body;a substantially annular crown extending substantially longitudinally from said bit body, said crown defining a crown distal end and a substantially longitudinally opposed crown proximal end, said crown extending from said bit body with said crown proximal end located substantially adjacent to said body distal end, said crown defining a crown passageway extending substantially longitudinally therethrough, said crown passageway being in fluid communication with said body passageway for receiving said fluid from said body passageway, said crown extending between a crown inner diameter and a crown outer diameter;said crown including a plurality of segments, each of said segments extending only partially circumferentially and radially across said crown.