US3696875A

US3696875A - Diamond-studded drilling tool

Info

Publication number: US3696875A
Application number: US877341A
Authority: US
Inventors: Abel C Cortes
Original assignee: Compagnie Francaise des Petroles SA
Current assignee: Total Compagnie Francaise des Petroles SA
Priority date: 1969-03-19
Filing date: 1969-11-17
Publication date: 1972-10-10
Anticipated expiration: 1989-10-10
Also published as: YU33125B; CH528008A; PL74590B1; BR7017010D0; DE1954576C3; DE1954576A1; FR2029963A5; GB1310883A; SU547179A3; YU3470A; NL152053B; NL6919217A; BE740959A; ES375650A1; DE1954576B2; RO58895A; CS193458B2

Abstract

A high output drilling tool for earth of any nature, the drilling tool having openings for the injection of sludge and protuberances distributed over the end surface whose average height is several times greater than its average thickness and which have attack edges for tearing away earth.

Description

[451 Oct. 10,1972

United States Patent Cortes xxxxx 39000 01119 7MMMMB 155555 "77777 11111 u 505008 233333 L m m 0 s mm 2 J m r m w m L H m .P

s 9 Dm mm D o h m E D m DC 3 U m Wm T n mk mM 0% D AF C N 0 m u Mm m. m w m D m A N H M U U 659,574 3/l963 Canada......................l75/410 996,796 6/l965 GreatBritain.............l75/410 21 Appl. No.: 877,341

Foreign Application Priority Data March 9, 1969 France.....................

907 Primary Examiner-David H. Brown Att0rney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A high output drilling tool for earth of any nature, the

[58] Field of Search......l75/329, 330, 390, 391

175/ 40941 1 drilling tool having openings for the injection of sludge and protuberances distributed over the end surface [56] References Cited whose average height is several times greater than its UNITED STATES PATENTS average thickness and which have attack edges for tearing away earth.

2,38l,4l5 8/1945 Williams..........i....... .175/329 2,607,562 8/1952 Phipps......................175/391 19 Claims, 10 Drawing Figures PATENTEDUBT 10 I972 3.696. 875

sum 3 [IF 3 DlAMOND-STUDDED DRILLING TOOL BACKGROUND OF INVENTION 1 Field of the Invention This invention relates to a drilling tool of the diamond-studded blade type with a very great efficiency, regardless of the nature of the ground it goes through, and with a structure that makes it possible to prevent both jamming and deterioration due to shock or rapid wear and tear.

2. Description of Prior Art Rock drills, involving lateral diamond-studded blades, have already been used because of their speed of advance in certain types of terrain and their resistance to wear and tear, which made it possible to reduce the frequency of drilling gear exchange. The considerable shearing forces, to which these blades were subjected, produced cracks in their base and manufacturers had to give the blades a special structure; these blades come in the form of a series of detachable blocks so that the development of the beginning of a crack in one blade or even in the steel body of the tool will only bring about the breakage of a small part of the blade involved.

In order to reduce the risk of cracks due to shocks to certain parts of the blades against the wall of the drill hole even further, manufacturers have increased the stability of the tools around their rotation axis by pieces placed between the blades; the external cylindrical outline of the pieces served as a guide for the tools. This arrangement offers the advantage of not only eliminating the lateral shocks but it also gives the entire assembly a certain sturdiness.

However, this particular structure does not prevent impacts upon the parts of the blades that are situated outside the lateral regions of the tools. Furthermore, it was necessary in order to obtain a correct flow of the sludge and, consequently, to preserve the correct advance speed to provide nozzles in the pieces arranged between the blades; these nozzles come out in the vicinity of the lateral regions of the tools.

In order to make up for the more rapid wear and tear of the parts of the blades that are situated along the edge of the lateral regions of the tool, it wasdecided to strengthen the thickness of the regions of the blades containing particles of carbides, borides, or diamonds, that is to say, the attack edges of the blades, progressively increasing this thickness from the center of the tool to the periphery.

In spite of the progress that has been made, it has been impossible so far to obtain a rock drill which has a fast drilling speed, without premature wear and tear and without deterioration of the blades, as it goes' through various layers of terrain involving both hard rocks and clay soil that clogs the surface of the tool.

SUMMARY OF THE INVENTION The purpose of this invention is to provide a very high-yield drilling tool for terrain of any kind, featuring openings for the injection of sludge, characterized by the fact that this tool involves protuberances distributed over its end surface, each protuberance having an average height measured parallel to the axis of the tool several times greater than its average thickness and at the same time involving an attack edge and at least one peripheral surface for the attack of the ground, each protuberance being bordered, at least partially, by a hollow region whose depth is at least equal to the average height of the protuberance, these hollow regions, which succeed each other, thus allow passage for the earth that has been torn away.

In this way we get a tool capable of attacking earth not only through the periphery of the surfaces of the protuberances but also through their attack flanks; the succession of hollow regions bordering at least on a part of each of the protuberances here prevents the choking or clogging of the tool during passage in agglomerant soil.

Another object of the invention is to increase the output of such a tool by using, as protuberances, blades exclusively involving, in the regions of attack, a concretion of diamonds, sunk into a mass consisting of at least one of the carbides of the following metals: tungsten, titanium, tantalum, chromium, vanadium, niobium, molybdenum, or another metal that resists abrasion and at least one of the following metals: cobalt, nickel, molybdenum, or any other metal generally used in the current state of the art of powder metallurgy, the blades being distributed over the entire surface of the tool in concentric and adjacent groups, that is to say, by groups where the distances between theextreme edges of each blade of one group with respect to the axis of the tool are included within a predetermined minimum distance and a maximum distance, the minimum distance of the edges of the blades of one group being essentially identical to the maximum distance of the edges of the blades of the group which is adjacent to it on the inside, the blades of at least one group being staggered laterally with respect to the blades of the adjacent groups.

- We thus get a tool capable of not only retaining its output as it passes through hard ground, even clay earth whereas the previously known tools, involving only diamonds set in the points, would become clogged but also capable of offering even faster advancement when passing through ground, by virtue of the height of the protuberances, their nature, and the diamond- I studded concretion which they have on their attack surfaces.

Another object of the invention is to improve the output of drilling tools of the type mentioned above in hard ground by means of diamond-studded blades having a ground attack surface which works by means of scraping, which is perpendicular to the axis of the tool, the blades being arranged by groups consisting of blades whose abovementioned attack surfaces are one and the same plane, one of the edges of these surfaces constituting the attack edge of the said blades, this edge being inclined with respect to the radius situated in said plane and joining the axis of the tool at one end of the attack edge, each blade having furthermore the same vertical angle of clearance.

The importance of such a structure resides in the fact that it increases the output of the tool by making each blade work both through penetration into the ground, under the very heavy pressure exerted by the end of the attack edge, by means of the scraping of the attack surface on the ground, and by the breakup of the ground due to the decompression following the passage of the blade under heavy pressure.

Another object of the invention is the improvement of the output of drilling tools of the type described above in sticky ground by distributing the groups of blades in a concentric manner and by arranging the blades in such a way that the lower surfaces of the blade of one group are on the same level, with the corresponding levels of the various groups of blades first decreasing, with the tool presumably in the working position, and then increasing while passing from the central group to the peripheral concentric group, the blades belonging to two adjacent groups being staggered in such a way that the blades are arranged essen-.

tially along alignments both in the form of steps and in spirals, said lines being such that the succession of spaces between the blades of two consecutive alignments and belonging to one and the same group is continuous when passing from the blades of one group to the blades of the adjacent grou'p, thus permitting the flow of the sludge toward the periphery.

In this way we get a tool in which the arrangement of the blades and the rotation of the tool contribute to the movement of the sludge and of the ground that has been torn away toward the periphery.

Another object of the invention is a long-lasting drilling tool capable of withstanding shocks, a tool whose blades have at their base and on the side opposite their attack face counterforts or bracing ribs, said blades being attained by means of sintering on the basis of a compound made up of at least one of the carbides of the following metals: tungsten, titanium, tantalum, chromium, vanadium, niobium, molybdenum, or any other metal that resists abrasion, and at least one of the following metals: cobalt, nickel, molybdenum, or any other metal generally used in the current state of the art of sintering, particles of diamonds being incorporated in their lower portion and in their lateral radial portion over a thickness of 2-20 mm, the two being assumed to be in the drilling position. The body of the tool is made up of a compound containing at least one of the following materials: cobalt, nickel, molybdenum, carbide of tungsten WC, carbide of tungsten W C, carbide of chromium, of titanium, of tantalum, of vanadium, of niobium, said compounds incorporating, by infiltration, a brazing mixture containing at least two of the following elements: copper, nickel, iron, zinc, tin, silver, silicon boron, manganese, aluminum and lead, said brazing mixture representing 25-60 percent of the weight of said infiltrated compound.

Such a compound offers the advantage of giving great tenacity to the blades which thus resist shocks without breaking away from the body of the tool; besides, they permit a reduction in the thickness of the blades. From this we get a higher pressure of their surface which is in contact with the ground; this facilitates the breakaway of the ground or earth after the passage of each blade.

Other objects and characteristics of the invention will emerge in the course of the following specifications, reference being made to the attached drawing which, by way of nonrestrictive example, shows usone way of making this type of tool.

DESCRIPTION OF DRAWINGS In the drawing, we have the following: FIG. 1 represents a schematic plan view of the tool;

FIG. 2 is a cross-section view of the tool along the section II-II of FIG. 1, on which we have shown, on the same scale, the apparent outline of the groups of blades given by staggered axial-cross-sections, as well as the dimensions of the blades belonging to each group;

FIG. 3 is a cross-section view of a blade of the peripheral group;

FIG. 4 is a cross-section of anyblade along a plane essentially parallel to the lateral faces of the blade;

FIGS. 5-9 are axial half-cross-sections made, respectively, along planes OA, OB, OC, OD, and OE in FIG.

FIG. 10 is a perspective view of the tool.

DETAILED DESCRIPTION OF THE DRAWINGS The schematic plan view of FIG. 1 shows the distribution in terms of concentric groups on the body of the tool of the assembly of protuberances which we have represented in the example chosen in the form of blades. In this example, we have six groups and we have designated them by the numerical references 1-6, which are entered in the zones where we have the blades of one and the same group. The blades, such as blade 7 of group 4, for example, have a cross-section perpendicular to the axis of the tool which is essentially rectangular. The dotted lines 8 indicate the apparent outline of the base of blade 7, sunk in body 9 of the tool shown in FIG. 2, along cross-section IIII in FIG. I.

The outline of cross-section ll-II of the tool is shown at 10, in FIG. 2.The opening 11 of the conduit 12, moving the drilling sludge from the internal region 13, connected to the set of rods, is'on the hollow portion of the tool, situated between

blades

14 and 15, of group 2, FIG. 1.

The upper surfaces of these blades, in the position of the tool shown here, as well as that surface of blade 16, t

are situated at the same height indicated by lines 17 in FIG. 2, whereas the lower portions of these blades are implanted in the body of the tool at a height corresponding to that of the dotted line 18.

Likewise, the height of the single blade 19 in group 1 FIG. 1, situated between the

nozzles

11 and 20, corresponds to the height of line 21 in FIG. 2.

The blades, whose attack surfaces, perpendicular to the axis of the tool, are at the highest height or level correspond to the blades of group 3, such as, for example, blade 22. The height of their attack surface is indicated at 23, FIG. 2. In the version shown by way of example here, the blades have a length that is greater than that of the other blades.

Starting with group 3, the height of the attack surfaces of the blades in groups, 4, 5, and 6, FIG. 1, decreases, as indicated, respectively, by

lines

24, 25, and 26, in FIG. 2. We note in FIG. 1 that the straight lines of the attack edges of the blades are inclined with respect to the direction of movement represented by arrow 33.

All of the blades are obtained by sintering from a compound consisting of at least one of the carbides of the following metals: tungsten, titanium, tantalum, chromium, vanadium, niobium, molybdenum, or any other metal that resists abrasion, and at least one of the following metals: cobalt, nickel, molybdenum, or any other metal generally used in the current state of the art of sintering.

By way of example, we can select the following particular compounds deriving from the above composition:

By Wt. l. Carbide of tungsten 50 to 94 Cobalt 50 to 6 2. Carbide of tungsten 40 to 60 Carbide of titanium 30 to 50 Cobalt 4 to 10 3. Carbide of tungsten 60 to 85 Carbide of titanium 4 to 20 Carbide of tantalum l to 12 Cobalt 5 to 15 4. Carbide of chromium 80 to 95 Nickel 5 to 5. Carbide of chromium 60 to 80 carbide of titanium 10 to 20 Nickel 10 to 20 6. Carbide of titanium 20 to 40 Carbide of niobium 3 to [0 Nickel 39 to 50 Molybdenum 10 to 20 Aluminum 10 to 20 7. Carbide of titanium 20 to 40 Chrome 7 to 20 Nickel 30 to 50 Cobalt 7 to 20 Molybdenum l to 5 Furthermore, all of the blades have a vertical clearance angle of about 10, identical to the angle of the blade shown in FIG. 3 and corresponding to the blades of group 6. The latter are adjacent to the lateral portions 28, bearing on their lateral surfaces diamonds which are set in the body of the tool. In addition to this special feature, the blades reveal common characteristics and attack the ground in the same way. Attack edge 29 penetrates into the ground, while surface 30 exerts heavy pressure on the ground which is broken by attack edge 29. The decompression, which follows the passage of surface 30, causes the ground to be dislocated. Counterfort 31, the inclination of the attack edge 29, and the nature of the blade contribute, through their reciprocal effects, to the considerable increase in their resistance and their lifetime.

In order to prevent any removal of the blades due to the effect of the shocks, they are attached by means of metallurgical setting at the moment of the formation of the tool whose body is obtained from a compound containing at least one of the following materials: cobalt, nickel, molybdenum, carbide of tungsten WC, carbide of tungsten W C, carbide of chromium, of titanium, of tantalum, of vanadium, of niobium, in which we incorporate a brazing mixture. We arrange the blades in a mold, containing the above compound, and we bring the entire substance to a temperature that brings about the fusion of the brazing mixture. We thus get a tool whose infiltrated body brings about perfect implanation of the blades. We further improve the operation by arranging prior to heating a brazing mixture above the tool body, said brazing mixture being withdrawn after the formation of the tool. The brazing mixture incorporated here may represent -60 percent of the weight of the compound of carbides and of metals, incorporated here, such as molybdenum, nickel, and cobalt.

By way of nonrestrictive example, we might in particular mention the following compounds:

Among the brazing mixtures, we might mention, for example, the following compounds:

By Wt. 1. Copper 30 to 50 Nickel 5 to 25 Iron 1 to 2 2. Copper 25 to Tin 8 to 30 Nickel 3 to 60 as well as the binary compounds of copper, silver, or copper-tin, or tin-lead, as well as the composition copper-siliconboronmanganese.

Although we have given several examples of compounds of blades and of the tool body, it is obvious that one would not go beyond the framework of this invention if one were to add or replace certain bodies used in the aforementioned compounds with bodies having similar properties. Thus the blades could contain carbide of molybdenum and the metals used in the sinter compound with the carbide or carbides could include one of the following associations: cobaltmolybdenum-copper; iron-nickel-chromium; nickel-copper; nickel-chromium; nickelmolybdenum; cobaltmolybdenum or cobaltchromium.

The radial cross-section of any blade, such as the one shown in FIG. 4, gives us an example of the constitution of the blades and the tool. Zone 59, consisting of tungsten carbide alloyed with cobalt, for example, involves a diamond-studded concretion in working zone 55, thus conferring the required abrasion-resistance qualities to the attack surfaces which are perpendicular to the axis of the tool, such as 56, and to the lateral radial surfaces, such as 57. Zone 58, that is to say, the body of the tool, consists of for example tungsten carbide infiltrated by a brazing mixture having one of the abovementioned compositions.

The angle of clearance 32 with respect to the direction of rotation 33 of the tool, visible in FIG. 3 and common for the entire assembly of blades, makes it possible to move along portions of earth which have been torn away and to remove them via the sludge circulating in the free spaces between two adjacent lines of blades, arranged essentially in the form of steps and in spirals, such as line of

blades

34, 35, 36, and 22, on the one hand, and

line

37, 38, 39, and 40, on the other hand.

In order to show the importance of the spaces existing between two lines, we have shown in FIGS. 5-9 the half-cross-sections along sections 0A, OB, 0C, 0D, and OE, in FIG. 1.

In FIG. 5 we see, at 19, 15, 41, and 34, the edges of the blades bearing the same reference number shown in FIG. 1. The outline of the cross-section between the

blades

41 and 34 shows the level drop of the surface of the body of the tool along the edge of

line

34, 35, 36, and 22..

We have a similar profile between

blades

42 and 43 of cross-section OB, FIG. 6. This cross-section furthermore offersthe advantage of showing the very low level at which we have the single blade of group 1, FIG. 1, near opening 44 and blade 16.

The half-section along Section C, in FIG. 1, represented in FIG. 7, enables us to give the reader an idea of the depth of the space left free in the vicinity of the axis of the tool, between the region of group 1 and blade 22, as well as between this blade and blade 37.

FIG. 8 shows, on the one hand, the profile of the cross-section made along section OD, in FIG. 1, on the level of opening 20, and on the other hand the vertical prolongation 45 of the surface of the body of the tool bordering on

line

57, 38, 39, and 40, beyond blade 39. This vertical prolongation corresponds to the surface of the tool. between the

lateral blades

37 and 46.

The comparison of FIGS. 7 and 9 shows the abrupt variations in the. slope of the surface of the body of the tool for a very small variation in the direction of the plane of the cross-section in the positions corresponding to two homologous sectors. The gentle slope of part 47 is due to the fact that section OE is tangent to the attack edge of blade 40. On the other hand, portion 48, bordering on blade 49, is vertical as in the case in FIG. 8."

These spaces formed by consecutive lines of blades in the form of steps and spirals, perform a very important action during the operation of the tool in clay soil because they facilitate the evacuation of portions of earth that have been torn away and which are moved laterally outside the tool, simultaneously, by the action of the sludge injected into the hollow part of the tool and by the effect of rotation.

In FIG. 10, which illustrates the tool in perspective, we have shown the two lines of

blades

34, 35, 36, 22, and 37, 38, 39, 40 in order to illustrate the distribution of blade lines belonging to concentric and adjacent groups as well as the shape of the outline of the free spaces resulting from this. We can seethat such spaces are bordered on the side of the attack edges by surfaces that are essentially vertical and abrupt, such as 50, extending essentially along the upper edge 51 of blade 36 of group 4 on the level of the upper surfaces of the blades of the second adjacent group, that is to say, on

the level of the surface of blade 37 of group 6, whereas these spaces are bordered on the opposite side of the blades by

counterforts

52 and 53, belonging, respectively, to blade 39 of group 4 and to blade 38 of adjacent group 5. Between

blades

40 and 54, we see the open space left for the housing of the blades of group 2 and group 1 whose upper surfaces are on a level lower than that of the working surfaces for the scraping of the blades, such as 22 in group 3.

Although we have shown in our drawing here only one way of making this tool in making this invention, it is obvious that numerous detail modifications may be made in the body or in the blades themselves without going beyond theframework of the invention. Thus,

counterforts such as 52 could start from only one portion of the blade situated well below the chamfer and connect the prolongation of the attack edge of the adjacent blade of the immediately higher group, the tool being in drilling position. Similarly, the base of the body of the tool may have any appropriate form with a view to its attachment to the end of the set of rods or it may on the contrary be adapted with a view to its connection to an intermediate tool. This is why the lower portion of the cross-section in FIG. 2 has not been shown in detail.

The number of blades or protuberances, per unit of surface, may vary and the thickness, the length, and the height vary as a function of the number of blades or protuberances per unit of surface.

. Finally, although the blades have been represented here with a chamfer bordering on two sides of the attack surface, we could also have further reduced the attack surface and we could have refrained from introducing the chamfer.

What is claimed is:

1. A high output drilling tool for ground of any nature and having openings through the end portion thereof for the injection of sludge, said drilling tool comprising, a plurality of independent protuberances individually distributed over its end surface, each independent protuberance having a separate counterfort for support thereof, each protuberance having an average height measured parallel to the axis of the tool which is at least twice its average thickness and having an attack edge and at least one peripheral surface for attacking ground, a depression formed in said drilling tool adjacent each protuberance on the attack edge side thereof whose depth is at least equal to the average height of the protuberance, said depressions lying adjacent each other and having sufficient width to provide continuous flow paths for the ground that has been torn away.

2. A drilling tool according to claim 1, wherein said protuberances include blades bearing exclusively in the attack regions a concretion of diamonds sunk in a sintered mass comprising at least one of the carbides of tungsten, titanium, tantalum, chromium, fanadium, niobium, molybdenum, and at least one of the following metals; cobalt, nickel, molybdenum, the blades being distributed over the end surface of the tool in concentric and adjacent groups, that is to say, by groups where the distances of the extreme edges of each blade of a group with respect to the axis of the tool are included within a predetermined minimum radial distance and a maximum radial distance, the minimum distance of the edges of the blades of one group being essentially identical to the maximum distance of the edges of the blade of the group which is internally adjacent to it, the blades of at least one group being staggered laterally with respect to the blades of the adjacent groups.

3. A drilling tool in accordance with claim 1, wherein the protuberances include diamond-studded blades, having a surface for attacking the ground by means of scraping, said surface being perpendicular to the axis of the tool, the blades being distributed by groups consisting of blades whose attacksurfaces are inthe same plane, one of the edges'of the attack surfaces constituting the attack edge of said blade, said edge being inclined with respect to the radius situated in said plane and joining the axis of the tool at one end of the attack edges, each blade having furthermore the same vertical angle of clearance.

4. A drilling tool in accordance with claim 3, wherein said groups of blades are concentric, the corresponding levels of the various groups of blades all decrease from the axis of the tool when the tool is in the working position, and increasing from the central group to the peripheral concentric group, the blades belonging to two adjacent groups being staggered in such a way that the blades are arranged essentially along lines that constitute both steps and spirals, said lines being such that the succession of spaces between the blades of two consecutive lines and belonging to one and the same group will be continuous from the blades of one group to the blades of another adjacent group, thus permitting the flow of the sludge toward the periphery.

5. A drilling tool in accordance with claim 4, wherein the blades have counterforts and where the space between two consecutive lines of blades, in spirals and in steps, is bordered, on the side of the attack edge of the blades, by a surface that is essentially verticla and that essentially extends, for each blade, from the level of its lower working surface to the level of the surface corresponding to the blades belonging to the second adjacent concentric group, said space being limited on the side opposite the attack edge by a surface consisting of steps, made up of the counterforts of the blades of the consecutive line belonging to the first and to the second adjacent groups.

6. A drilling tool in accordance with claim 1, wherein said protuberances are essentially lined up in steps and spirals, the lines thus formed being essentially symmetrical with respect to the axis of the tool, leaving between them spaces whose width is at least equal to the average width of the protuberances.

7. A drilling tool in accordance with claim 1, wherein said protuberances reveal counterforts at their base and the side opposite their attack edge, the base of said counterforts extending in the direction opposite the attack edges at least to the level of the rearward portion of the radially inward edge of the attack surface of the nearest radially outward protuberances, the level of the nearest radially outward protuberance being higher than the protuberance from which said counterfort extends when the tool is in the drilling position.

8. A drilling tool in accordance with claim 1, wherein said protuberances are blades obtained by sintering from a compound made up of at least one carbide of tungsten or of titanium, tantalum, chromium, vanadium, niobium, molybdenum, and at least one of the following metals: cobalt, nickel, molybdenum, particles of diamonds being incorporated in their lower portion and in their lateral radial portion over a thickness of 2-20 mm, the tool being assumed to be in drilling position.

9. A drilling tool in accordance with claim 1, wherein said protuberances are blades attached, by metallurgical setting, to a tool body consisting of a compound containing at least one of the following bodies: cobalt, nickel, molybdenum, tungsten carbide WC, tungsten carbide W C, carbide of chromium, titanium, tantalum, vanadium, niobium, said compound incorporating, by infiltration, a brazing mixture containing at least two of the following elements: copper, nickel, iron, zinc, tin,

all.

silver, silicon, boron, manganese, aluminum, lead, said brazing mixture representing 25-60 percent of the weight of said infiltrated compound.

10. A drilling tool in accordance with claim 8, wherein said blades are incorporated in the body of the tool by metallurgical setting, the body being made up of a compound obtained by infiltration, including at least one carbide of abrasion-resistant metal and a brazing mixture, said brazing mixture having a concentration, within the mass, of at least 25 percent of the weight of the compound.

11. A drilling tool in accordance with claim 1, above, whose protuberances are blades revealing a ground attack surface perpendicular to the axis of the tool and an attack surface parallel to said axis, the blades being distributed in the form of concentric groups, each blade of a group extending in the direction of its length, in a direction inclined with respect to the direction of its horizontal displacement, and each of the two extreme edges of each of the blades of the group being, respectively, at the same predetermined distance from the axis of the tool.

12. A drilling tool in accordance with claim 11, wherein the blades involve at least one chamfer at at least one end.

13. A drilling tool in accordance with claim 1, wherein the protuberances are distributed over the surface of the tool in concentric groups, the attack surfaces of one of the groups being at a level lower than that of the attack surfaces of the other groups when the tool is in drilling position, the protuberances of said group having an average length that is greater than the length of the protuberances of the other groups.

14. A drilling tool in accordance with claim 1, having a protuberance one of whose edges coincides with the axis of the tool.

15. A drilling tool with blades for terrain of any nature, characterized by the fact that the blades involve, exclusively in the attack regions, a concretion of diamonds sunk in a mass consisting of at least one of the carbides of the following metals: tungsten, titanium, tantalum, molybdenum, chromium, vanadium, niobium, and at least one of the following metals: cobalt, nickel, molybdenum, the blades being attached to the body of the tool by metallurgical setting, the body of the tool being made up of a compound containing at least one of the following materials: cobalt, nickel, molybdenum, tungsten carbide WC, tungsten carbide W C, carbide of chromium, of titanium, of tantalum, of molybdenum, of vanadium, of niobium, said compound incorporating, by infiltration, a brazing mixture containing at least two of the following elements: copper, nickle, iron, zinc, tin, silver, silicon, boron, manganese, aluminum, and lead, said brazing mixture representing 25-60 percent of the weight of said infiltrated compound, the assembly of the blades being distributed in I concentric groups over the end surface of the tool, each blade of a group extending in the direction of its length in a direction inclined with respect to the direction of its horizontal displacement, each of the two extreme edges of each of the blades of the group being located respectively at the same predetermined distance from the axis of the tool, the maximum distance of the edges of the blades of each group coinciding essentially with the minimum distance of the edges of the blades from the adjacent group which surrounds it, the scraping attack surfaces of the blades belonging to one and the same group being in one and the same plane perpendicular to the axis of the tool, whereas the attack edgesof said surfaces are inclined with respect to the radii situated in their plane and joining the axis of the tool to the ends of the attack edges, each blade possessing furthermore a vertical angle of clearance as well as a counterfort at the base of the side opposite the attack edge connecting to the element of the surface that prolongs the attack surface of the blade that is contiguous with theadjacent group, the levels of the blades of one group decreasing at first and the increasing as we go from the blades of the group near the axis of the tool, presumed in drilling position, to the blades of the peripheral groups, the blades belonging to two adjacent groups here being staggered in such a way that the blades are arranged essentially in steps and in spirals and that the spaces formed between two consecutive lines are bordered on the one hand by abrupt walls, extending essentially from each blade from the level of its lower working surface to the level of the surface corresponding to the blades belonging to the second adjacent group and, on the other hand, by a surface consisting of steps made up of the counterforts of the consecutive line of blades belonging to the first and to the second adjacent groups, the smallest distance between two lines, measured in the direction of rotation of the tool, being at least equal to the width of one blade.

16. In a drilling tool comprising a main body and protuberances extending at least from the end face of said body, at least one of said protuberances having a drilling face disposed in a direction substantially perpendicular to the direction of its extension from said main body, the improvement comprising said protuberances being formed of a material comprising a concretion of diamonds sunk in a mass consisting of at least one of the carbides of an abrasion-resistant metal selected from the group consisting of tungsten, titanium, tantalum, molybdenum, chromium, vanadium and niobium, and at least one metal selected from the group consisting of cobalt, nickel and molybdenum, wherein said protuberances are attached to said main body by a metallurgical setting, wherein said main body comprises a material containing at least one member selected from the group consisting of cobalt, nickel, molybdenum, tungsten carbide, and a carbide of a member selected from the group consisting of chromium, titanium, tantalum, molybdenum, vanadium and niobium, and wherein said material has incorporated therein, by infiltration, from 25 to 60 percent by weight, based on the weight of said material, of a brazing mixture containing at least two members selected from the group consisting of copper, nickel, iron, zinc,

tin, silver, silicon, boron, manganese, aluminum and diamonds bearing exclusively in the attack r gions of said blades, said slntered mass comprising at east one of the carbides of tungsten, titanium, tantalum, chromium, vanadium, niobium, molybdenum, and at least one of the following metals: cobalt, nickel, molybdenum, each protuberance having an attack edge and at least one peripheral surface for attacking ground, a depression formed in said drilling tool adjacent each protuberance on the attack edge side thereof, said depressions lying adjacent each other and having sufficient width to provide continuous flow paths for the ground that has been torn away, and a counterfort at the base of each blade and opposite its attack edge, the base of said counterforts extending in the direction opposite the at tack edges of said protuberances at least to the level of a rearward portion of the radially inward edge of the attack surface of the nearest radially outward protuberance, the level of the nearest radially outward protuberance being higher than the protuberance from which' said counterfort extends when the tool is in the drilling position.

18. A high output drilling tool for ground of any nature as recited in claim 17, wherein said blades are distributed over the end surface of the tool in concentric and adjacent groups, that is to say, by groups where the distances of the extreme edges of each blade of a group with respect to the axis of the tool are included within a predetermined minimum radial distance and a maximum radial distance, the minimum distance of the edges of the blades of one group being essentially identical to the maximum distance of the edges of the blades of the group which is internally adjacent to it, the blades of at least one group being staggered laterally with respect to the blades of the adjacent group.

19. A high output drilling tool for ground of any nature as recited in claim 17, wherein the depth of each depression is at least equal to the average height of the protuberance adjacent which the depression is formed.

Claims

3. A drilling tool in accordance with claim 1, wherein the protuberances include diamond-studded blades, having a surface for attacking the ground by means of scraping, said surface being perpendicular to the axis of the tool, the blades being distributed by groups consisting of blades whose attack surfaces are in the same plane, one of the edges of the attack surfaces constituting the attack edge of said blade, said edge being inclined with respect to the radius situated in said plane and joining the axis of the tool at one end of the attack edges, each blade having furthermore the same vertical angle of clearance.

9. A drilling tool in accordance with claim 1, wherein said protuberances are blades attached, by metallurgical setting, to a tool body consisting of a compound containing at least one of the following bodies: cobalt, nickel, molybdenum, tungsten carbide WC, tungsten carbide W2C, carbide of chromium, titanium, tantalum, vanadium, niobium, said compound incorporating, by infiltration, a brazing mixture containing at least two of the following elements: copper, nickel, iron, zinc, tin, silver, silicon, boron, manganese, aluminum, lead, said brazing mixture representing 25-60 percent of the weight of said infiltrated compound.

15. A drilling tool with blades for terrain of any nature, characterized by the fact that the blades involve, exclusively in the attack regions, a concretion of diamonds sunk in a mass consisting of at least one of the carbides of the following metals: tungsten, titanium, tantalum, molybdenum, chromium, vanadium, niobium, and at least one of the following metals: cobalt, nickel, molybdenum, the blades being attached to the body of the tool by metallurgical setting, the body of the tool being made up of a compound containing at least one of the following materials: cobalt, nickel, molybdenum, tungsten carbide WC, tungsten carbide W2C, carbide of chromium, of titanium, of tantalum, of molybdenum, of vanadium, of niobium, said compound incorporating, by infiltration, a brazing mixture containing at least two of the following elements: copper, nickle, iron, zinc, tin, silver, silicon, boron, manganese, aluminum, and lead, said brazing mixture representing 25-60 percent of the weight of said infiltrated compound, the assembly of the blades being distributed in concentric groups over the end surface of the tool, each blade of a group extending in the direction of its length in a direction inclined with respect to the direction of its horizontal displacement, each of the two extreme edges of each of the blades of the group being located respectively at the same predetermined distance from the axis of the tool, the maximum distance of the edges of the blades of each group coinciding essentially with the minimum distance of the edges of the blades from the adjacent group which surrounds it, the scraping attack surfaces of the blades belonging to one and the same group being in one and the same plane perpendicular to the axis of the tool, whereas the attack edges of said surfaces are inclined with respect to the radii situated in their plane and joining the axis of the tool to the ends of the attack edges, each blade possessing furthermore a vertical angle of clearance as well as a counterfort at the base of the side opposite the attack edge connecting to the element of the surface that prolongs the attack surface of the blade that is contiguous with the adjacent group, the levels of the blades of one group decreasing at first and the increasing as we go from the blades of the group near the axis of the tool, presumed in drilling position, to the blades of the peripheral groups, the blades belonging to two adjacent groups here being staggered in such a way that the blades are arranged essentially in steps and in spirals and that the spaces formed between two consecutive lines are bordered on the one hand by abrupt walls, extending essentially from each blade from the level of its lower working surface to the level of the surface corresponding to the blades belonging to the second adjacent group and, on the other hand, by a surface consisting of steps made up of the counterforts of the consecutive line of blades belonging to the first and to the second adjacent groups, the smallest distance between two lines, measured in the direction of rotation of the tool, being at least equal to the width of one blade.

16. In a drilling tool comprising a main body and protuberances extending at least from the end face of said body, at least one of said protuberances having a drilling face disposed in a direction substantially perpendicular to the direction of its extension from said main body, the improvement comprising said protuberances being formed of a material comprising a concretion of diamonds sunk in a mass consisting of at least one of the carbides of an abrasion-resistant metal selected from the group consisting of tungsten, titanium, tantalum, molybdenum, chromium, vanadium and niobium, and at least one metal selected from the group consisting of cobalt, nickel and molybdenum, wherein said protuberances are attached to said main body by a metallurgical setting, wherein said main body comprises a material containing at least one member selected from the group consisting of cobalt, nickel, molybdenum, tungsten carbide, and a carbide of a member selected from the group consisting of chromium, titanium, tantalum, molybdenum, vanadium and niobium, and wherein said material has incorporated therein, by infiltration, from 25 to 60 percent by weight, based on the weight of said material, of a brazing mixture containing at least two members selected from the group consisting of copper, nickel, iron, zinc, tin, silver, silicon, boron, manganese, aluminum and lead.

17. A high output drilling tool for ground of any nature and having openings through the end portion thereof for the injection of sludge, said drilling tool comprising a plurality of independent protuberances individually distributed over its end surface, said protuberances including blades having a concretion of diamonds sunk in a sintered mass, said concretion of diamonds bearing exclusively in the attack regions of said blades, said sintered mass comprising at least one of the carbides of tungsten, titanium, tantalum, chromium, vanadium, niobium, molybdenum, and at least one of the following metals: cobalt, nickel, molybdenum, each protuberance having an attack edge and at least one peripheral surface for attacking ground, a depression formed in said drilling tool adjacent each protuberance on the attack edge side thereof, said depressions lying adjacent each other and having sufficient width to provide continuous flow paths for the ground that has been torn away, and a counterfort at the base of each blade and opposite its attack edge, the base of said counterforts extending in the direction opposite the attack edges of said protuberances at least to the level of a rearward portion of the radially inward edge of the attack surface of the nearest radially outward protuberance, the level of the nearest radially outward protuberance being higher than the protuberance from which said counterfort extends when the tool is in the drilling position.