US3044219A - Apparatus for resharpening diamond drill bits - Google Patents

Description

c. R. CUTLER 3,044,219

APPARATUS FOR RESHARPENING DIAMOND DRILL BITS July 17, 1962 5 Sheets-Sheet 1 Filed Feb. 9. 1959 mmvron. GI /n21. ES R. Car; 52

July 17, 1962 c. R. CUTLER 3,044,219

APPARATUS FOR RESHARPENYING DIAMOND DRILL BITS Filed Feb. 9, 1959 3 Sheets-Sheet 2 IN V EN TOR.

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APPARATUS FOR RESHARPENING DIAMOND DRILL BITS Filed Feb. 9. 1959 C. R. CUTLER July 17, 1962 3 Sheets-Sheet 3 w m M A 4 a i 5 9 v/ a 7 W W W R m m w.

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United States Patent 3,044,219 APPARATUS FOR SHARPENING DIAMDND DRILL BITS Charles R. Cutler, Salt Lake City, Utah, assignor to Christensen Diamond Products Company, Salt Lake City, Utah, a corporation of Utah Filed Feb. 9, 1959, Ser. No. 792,115 20 Claims. (Cl. 51-15) The present invention relates to apparatus for resharpening diamond drill bits, and more particularly to apparatus for blasting abrasive particles against such drill bits.

Diamond drill bits are used for drilling holes in relatively hard substances, such as encountered in mining operations, oil well drilling, and coring of formations. A diamond drill bit of the impregnated type has its diamond cutting elements embedded throughout a supporting matrix. A bit of this type may be self-sharpening because of the wearing away of the matrix to progressive- 1y expose additional diamonds as the bit is. being used. However, such self-sharpening may not occur when the bit is operating upon certain formations. It, therefore, becomes necessary to remove the bit from the hole being drilled and resharpen it to expose and utilize additional diamond cutting elements.

An-object of the invention is to provide an improved apparatus for resharpening diamond drill bits by blasting abrasive particles upon their cutting faces.

Another object of the invention is to provide an abrasive blasting apparatus capable of blasting abrasive material, against the entire area of the cutting face of the diamond drill bit to effect its resharpening.

A further object of the invention is to provide an abrasive blasting apparatus capable of resharpening diamond drill bits of various sizes, with assurance that the abrasive material will be directed against the entire drilling face of each bit.

An additional object of the invention is to provide an abrasive blasting apparatus for resharpening diamond drill bits, in which the abrasive-laden fluid or liquid jetted against the drill bit is effectively removed from the region of the drill bit and the abrasive particles, and in which such abrasive particles are then separated from the liquid or fluid jetting medium, to permit their subsequent reuse.

Yet another object of the invention is to provide an apparatus for blasting or jetting abrasive particles upon a drill bit, which is capable of being used at isolated drilling sites and is comparatively economical to manufacture and easy to use.

This invention possesses many other advantages, and

has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose Of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a side elevational view of an apparatus embodying the invention;

FIG. 2 is a bot-tom plan view of the apparatus disclosed in FIG. 1;

FIG. 3 is an enlarged vertical section taken along the line 3.-3 on FIG. 1;

FIG. 4 is a cross-section taken along the line 4-.-4 on FIG. 3;

FIG. 5 is a cross-section taken along the line 5-.-5 on FIG. 3;

FIG. 6 is a cross-section taken along the line 6-6 on FIG. 3;

FIG. 7 is an enlarged fragmentary section through a part of the liquid turbine portion of the apparatus.

The apparatus illustrated in the drawings has been particularly designed to expose diamond cutting elements lti embedded in a diamond drill bit 11, such as illustrated by way of example in FIG. 3. The diamond drill bit discrosed is of the core type, and may have an upper threaded pin liz for threaded attachment to a tubular drill string (not shown), by means of which the drill bit is rotated while in use. On its lower face 13, the bit has diamond particles or stones 10 embedded in its matrix, such diamond particles also being embedded on the outer reaming face 14 of the bit, as Well as on its inner reaming face 15. The bit may be of the impregnated type, in which the diamonds are dispersed throughout the mass of the matrix extending between the inner and outer reaming faces 15, 14.

When the drill bit 11 is used in drilling a formation, the exposed diamonds may break out of the matrix and become lost, whereupon the matrix material itself must wear away between the underlying diamonds before they are exposed and are able to perform their cutting action upon the formation. If such exposure does not occur, then the bit is dulled and must be pulled from the hole. By virtue of the present invention, the matrix material in which the diamonds are embedded is blasted away by jetting abrasive particles thereagainst to expose the diamonds and permit the bit to be run in the bore hole once again for continued use in drilling the hole.

The apparatus includes an outer casing or housing 16 having a lower tapered hopper portion or bowl 1 7. The drill bit 11 has its pin 12 threadedly attached to the threaded box 18 of an adapter 19- removably secured to a rotatable shaft 29- by means of a threaded stud 21. This shaft is supported, in a vertical position through the agency of a bearing structure 22 and the upper cover 23 of the housing, this cover being suitably attached to the latter. As shown, the inner race 24 of the bearing structure is clamped between a shaft shoulder 25 and a handwheel 26 externally of the cover, the handwheel being secured on the shaft 28. by a nut 27 threadedlyattached to the outer end of the shaft and tightened against a washer 28, which, in-turn, bears against the handwheel, thehandwheel engaging an upwardly extending shoulder 29 on, the shaft. Rolling bearing elements 30, such as bearing balls, are rollable on the inner raceway 2.4, and

also on an encompassing outer raceway 31 secured within the central hub 32 of the cover 23, the end of the outer raceway bearing against the upwardly facing shoulder 33. of the cover surrounding the shaft shoulder 25. By virtue of the ball bearing arrangement disclosed, the shaft 26, adapter 19, and bit 11 are mounted for rotation in the housing 16, the bearing structure preventing axial movement of the shaft 20 in both longitudinal directions.

The shaft 20 is rotated by a fluid or liquid turbine, which includes a rotor 35 fixed to the shaft and having blades or buckets 36 on its peripheral portion against which-fluid is. adapted to strike. Such fluid discharges through nozzle 37 threadedly attached to the housing 16 and directed substantially tangentially of the turbine rotor 35. The fluid under velocity engages orstrikes the turbine blades and effects rotation of the rotor, as well as the shaft 20, adapter 19, and drill bit 11 mounted in the threaded box 18 of the latter. In order to vary the speed of rotation of the rotor 35, the jet of fluid or liquid discharging from the nozzle may be deflected laterally to some extent by a deflector member38, which is disclosed as being in the form of a screw threaded within a bore 39 in the housing 16 and adapted to be disposed in various .positions across the stream 'The deflector screw 38 can be turned'by grasping its outer issuing from the nozzle 37.

knurled head 4%, which will effect inward or outward feeding of the screw with respect to the housing and the nozzle outlet. The screw can be held in any position of adjustment by tightening a lock nut 41 threaded thereon against the exterior of the housing.

The housing is supported from the ground or a suitable surfaceG by a plurality of supporting legs 42 threadedly attached thereto. These legs also elevate the bowl portion. 17 of the housing above the supporting surface and provide space below the bowl for the jetting or nozzle blasting portion of the apparatus. Such portion includes a housing extension 43 depending from the lower portion of the tapered how] 17, and carrying a liner 44 therewithin which is suitably secured thereto. Mounted in this liner is a nozzle carrier or distributor head 45 which has a jet orifice or nozzle 46 mounted in its upper end and adapted to direct a jet of fluid, such as water, against the faces of the drill bit 11 as the latter rotates within the housing 16. The fluid, such as water, enters the housing extension 43 from a fluid inlet pipe 47, the fluid passing into an interior chamber 48 of the nozzle carrier 45 through side ports 49 in the latter provided between the upper and lower ends 59, S1 of the carrier, which engage the inner wall 52 of the liner 44. The intermediate portion 53 of the carrier between its upper and lower ends is reduced in diameter to provide an annular space 54 into which the water or liquid can enter, for passage through the ports 49 to the inner chamber 48 within the carrier that'communicates with the inlet of the nozzle 46. Leakat a suitable pressure is delivered to the nozzle 46 through the inlet pipe 47 and also to the turbine nozzle 37 through a branch line 63 connected to this inlet pipe and running to the turbine nozzle. The water issuing from the turbine nozzle 37 will impact upon the turbine blades 36 and rotate the rotor 35 and the drill bit 11. At the same time, the water is flowing into the housing extension 43, passing through the ports 49 to the inlet side of the nozzle 46, the nozzle axis being arranged vertically and being disposed under the face of the bit 11. While the bit is r0tating, the water will jet in an upward direction against the face of the bit.

The tapered hopper portion or bowl 17 contains a suitable abrasive material, such as a grinding compound, silicon carbide, or aluminum oxide, which, for example, may be of 36 to 60 mesh. The water picks up the abrasive particles and blasts them against the face of the bit, eroding the matrix material between the diamonds 10 and thereby exposing the diamonds in the bit matrix. The abrasive blasting action will occur while the bit 11 is being rotated at a proper speed by the impacting of the Water against the turbine blades 36. As an example, the turbine rotor or wheel 35 may be rotated between about 50 to 209 rpm. After theapparatus has been operating for a suitable length of time, the matrix material will have been worn away sufficiently to expose the diamonds 10 and thereby eifect a resharpening of the bit.

The water discharged from the nozzle 46 and the abrasive particles jetted against the bit '11 will move upwardly age of fluid in both an upward and a downward direc tion between the nozzle carrier 45 and the liner 44 is prevented by an upper-side seal 55 mounted on the carrier and sealingly engaging the inner wall of the liner of the liner above the inlet 56 and by a lower side seal 57 mounted on the lower portion of the carrier and sealingly engaging the inner wall of the liner below the inlet 56.

The nozzle carrier 45 is yieldably held in an upward position by a helical compression spring 58 surrounding a depending stem 59 integral or otherwise secured to the carrier 45 and extending downwardly through a lower head 60 threadedly attached to the lower end of the housing Q or outlet end 72 of this inner tube. Such upward move around the bit and the adapter 19, passing into an inlet 7 0 in an inner enclosure or tube 71 surrounding the adapter and its threaded box 18 and discharging through the upper ment is assisted by a lifting device mounted on the drive shaft 20 in the form of an agitator 73 clamped between the adapter 19 and a shoulder 74 on the shaft. This agitator has circumferentially spaced paddles 75 that are pitched in a direction to eifect a lifting action on the abrasive liquid in the housing 16 .and within the tube 71. As

extension 43. The lower end' of the spring 58 engages a spring seat 61 provided onthis head 60, its .upper end en'- gaging the nozzle carrier and urging the latter upwardly to hold its upper end engaged with an upper flange 62 on the liner 44. Passage of fluids and other substances between the upper end of the carrier and the flange 62 is prevented by a gasket type of seal 63 on the nozzle carrier 45 engaging the undersurface of the flange or shoulder 62. i L

The position of the nozzle 46 with respect to the drill bit 11 can be changed, to enable the apparatus to blast or direct a jet of fluid against the faces of drill bits 11 of different diameters. Such shifting or change'of the nozzle position is effected by turning an operating or shifting handle 64, attached to the carrier stem 59 by, means of a result, the abrasive laden liquid that has been blasted upon the bit 11 is lifted through'the tube 71 and will discharge through its upper or outlet end 72, then passing outwardly thereof and engaging a circumferential shield or baffle 76 depending from the rotor 35 and spaced outwardly of the inner tube 71. The abrasive laden fluid will then drop downwardly through the annular space 77 between theinner tube 71 and an outer enclosure or bafile tube 78 that extends downwardly to a region near the upper end of the tapered hopper portion or bowl 17 of the housing. Due to the decreased velocity of the abrasive laden fluid as it gravitates through the annular space 77 between the inner and outer tubes 71, 78, the abrasive material will separate or settle out of the liquid or water and ber 81 that communicates with a fluid outlet pipe 82, where the nut 65 threaded on the inner end of the handle, thereby turning the nozzle carrier 45 about. its axis, which is disposed eccentrically of the axis of rotation of the drill bit 11 and shaft 20 to which it is, secured through the agency of the adapter 19. It is evident that by turning the operating handle 64, that extends radially from the stem 59, the nozzle 46, which is mounted in the nozzle carrier 45 eccentrically of its axis of turning, will be shifted toward and from the axis of the bit 11, so as to variously locate the nozzle with respect to the face of the bit disposed hit 11, and also for rotating the turbine rotor 35. Water; I

the water may pass back to its original source, to be pumped at the proper pressure into the fluid inlet pipe 47 .i

The inner and outer tubular members 71, 78 are appropriately supported by virtue of the fact that the outer tubular member 78 rests upon circumferentially spaced supporting lugs 83 extending inwardly of the housing wall. The inner tube or enclosure71 is supported from the outer tube 78. As shown, the inner tube may be rolled into a generally cylindrical form with its ends 84 overlapping (FIGS. 3 and 4) A rivet 85 passes through such overthereabove. The position of the nozzle 46 is indicated by y lapping ends to secure them together and also through the outer tube 78, th'e rivet extending through a suitable spacer tube 86, the ends of which engage the inner and the outer tubes. Similarly, circumferentially spaced rivets are secured to and extend radially between the inner and outer tubes 71, 78, there being spacer members 86 surrounding these rivets and engaging the inner and outer enclosures or tubes. The circumferentially spaced rivets and spacer tubes thereby retain the inner and outer enclosures 71, 78 circumferentially spaced from one another, with the inner enclosure 71 supported by the outer enclosure 78, and in proper position around the drive shaft 20, agitator unit 73, adapter 19 and drill bit 11 attached to the adapter box 18.

The screen 30 extends circumferentially around the housing 16 and is clamped against its inner wall by an outwardly expandible cage 9%, which includes an upper ring 91 and a lower ring 92, both rings engaging the inner surface of the screen 89 to force it against the upper and lower wall portions 93, 9-: of the surrounding housing 16 on opposite sides of the annular space or chamber 81. The upper and lower rings 91, 92 are held in vertically spaced relation by intervening ribs 95 integral therewith. The cage structure 90, which is split, has end ribs 96 on opposite ends of its split that merge into inwardly directed and opposed flanges 97. An expansion screw 98 is threadedly mounted in one of the flanges 97 and is adapted to engage the other flange 97. Tightening of such screw will move the flanges 97 away from one another and will expand the entire cage structure 98, causing the upper and lower rings 91, -92 to bear against the screen 80 and clamp it against the upper and lower walls 93, 94 of the housing. The screen 80 is readily removable for cleaning or re placement by loosening the expansion screw 98, allowing the cage structure 98 to retract and permitting it to be removed upwardly from the housing 16 when the cover 23 and the mechanism internally of the housing has been removed.

It is apparent that the turbine rotates the drill bit 11, and the nozzle 46 positioned under the cutting faces of the latter will continuously blast the abrasive particles thereagainst to erode the bit matrix. The agitator unit 73 will insure the lifting of the water and abrasive mixture upwardly through the inner tube 71, such mixture passing out of its upper end 72 and then laterally outward, being deflected by the turbine baflie 76 and dropping downwardly through the annular space 77 between the inner and outer tubes, during which time the abrasive material separates from the water and is guided by the convergent wall of the hopper 17 back toward the nozzle 46, to be picked up again by the water jetting out of this nozzle and impinged against the faces of the bit 11. Thus, the abrasive particles can be reused repeatedly for the purpose of sharpening the bit, the water exhausting through the outlet pipe 82 for suitable disposal or return to its initial source.

After the bit 11 has been sharpened, the cover 23 is disconnected from the housing 16 and handles ldli'attached to the upper end of the cover grasped, to lift the cover and all of the internal mechanism carried thereby from the housing 16, such internal mechanism including the turbine rotor 35, the shaft 20, agitator 73, adapter 19, and drill bit 11. The sharpened drill bit 11 can be removed and another drill bit threaded to the box 18 for resharpening purposes. If such drill bit is of a diflerent size, the adapter 19 can be changed to provide a proper size threaded box 18 for threaded attachment to thebit, after which the ap paratus is again inserted in the housing 16 and the cover 24 secured thereto. If a different size bit is now mounted in the adapter 19, the operating handle 64 is turned appropriately, to shift the nozzle head 45 and place the nozzle 4-6 at the correct position for sharpening the bit. Water under pressure can then be caused to pass through the inlet pipe 47 and the branch pipe 68, to cause the abrasive particles to be blasted upon the faces of the bit 11, while the bit is being rotated by the liquid turbine.

If desired, the handle 64 can be manipulated during the blasting operation to shift the position of the nozzle 46 and insure that the jet issuing therefrom will be directed across all portions of the drilling faces of the bit 11.

The inventor claims:

1. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material; said mounting means supporting the drill bit adjacent to the quantity of abrasive material in said containing means; and nozzle means positioned to direct a fluid into and through the abrasive material in said containing means to blast said material directly against the drill bit.

2. In abrasive blasting apparatus-for drill bits: means for mounting a drill bit; means adapted to contain a quantity of abrasive material; said mounting means supporting the drill bit adjacent to the quantity of abrasive material in said containing means; and nozzle means positioned to direct a fluid into and through the abrasive material to blast said material in said containing means directly against the drill bit.

3. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material; said mounting means supporting the drill bit adjacent to the quantity of abrasive material in said containing means; a nozzle carrier; a nozzle in said carrier positioned to direct a fluid into and through the abrasive material in said containing means to blast said material against the drill bit; and means mounting said carrier for movement about an axis eccentric to the rotational axis of said mounting means, to enable said nozzle to be shifted toward and away from said rotational axis.

4. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted tocontain a quantity of abrasive material; said mounting means supporting the drill bit adjacent to the quantity of abrasive material in said containing means; nozzle means for directing a fluid through the abrasive material to blast said material against the drill bit; an enclosure surrounding at least part of said rotating means and into which abrasive laden fluid can pass after striking the drill bit, said enclosure having an outlet for the abrasive laden fluid; a passage through which the abrasive laden fluid exiting from said outlet can flow; means for directing the abrasive material from said passage toward said nozzle; and outletmeans for receiving the fluid from said passage.

5. In abrasive blasting apparatus for drill bits; means for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material; nozzle meansfor directing a fluid through the abrasive material to blast said material against the drill hit; an enclosure surrounding at least part of said rotating means and into which abrasive laden fluid can pass after striking the drill bit, said enclosure having an outlet for the abrasive laden fluid; a passage through which the abrasive laden fluid exiting from said outlet can flow; means for directing the abrasive material from said pas.- sage toward said nozzle; outlet means for receiving the fluid from said passage; and means rotatable with said mounting means for moving the abrasive laden fluid through said enclosure.

6. In abrasive blasting apparatus for drill bits; mean for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material below said mounting means; said mounting means supporting the drill bit above and adjacent to the quantity of abrasive material therebelow in said containing means; and nozzle means positioned to direct a fluid upwardly into and through the abrasive material in said containing means to blast said material upwardly against the 'drill bit.

7. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means for rotating said mount ing means and drill bit; means adapted to contain a quantity of abrasive material below said mounting means; said mounting means supporting the drill'bit above and adjacent to the quantity of abrasive material therebelow in aoagais 7 said containing means; nozzle means below said mounting means for directing a fluid upwardly through the abrasive material to blast said material upwardly against enclosure outlet; means for directing the abrasive material from said passage outlet toward said nozzle; and'outletmeans for receiving the fluid from said passage.

8. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material below said mounting means; said mounting means supporting the drill bit above and adjacent to the quantity of abrasive material therebeloiv in said containing means; nozzle means having an outlet below said mounting means for directing a fluid upwardly through the abrasive material to blast said material upwardly against the drill hit; an inner enclosure above said nozzle means outlet and surrounding at least part of said rotating means and into which abrasive laden fluid can pass upwardly after striking the drill ,bit, said enclosure having an upper outlet through which the upwardly moving adhesive laden fluid can discharge; an outer enclosure surrounding and spaced from said inner enclosure to provide an annular passage through which abrasive laden fluid from said outlet can'flow; said passage having an outlet substantially below said first enclosure outlet; means for directing the abrasive material from said passage outlet toward saidtnozzle; and outlet means for receiving the fluid from said passage.

9. In abrasive blasting apparatus for drill bits: means for mountings drill bit; means for rotating said mounting means and drill bit; means adapted to contain aquantity of abrasive material below said mounting means; said mounting means supporting the drill bit above and adjacent to the quantity of abrasive material therebelow in said containing means; a nozzle carrier; a nozzle in said carrier having an outlet below said mounting means for directing a fluid upwardly through the abrasive material to blast said material upwardly against the drill bit; means mounting said carrier for movement about an axis eccentric to the rotational axis of said mounting means, to

' enable said nozzle to be shifted toward and away from said rotational axis; an enclosure above said norlle outlet and surrounding at least part of said rotating means and into which abrasive laden fluid can pass upwardly after striking the drill bit, said enclosure having an upper outlet through which the upwardly moving abrasive laden fluid can discharge; a passage through which the abrasive laden fluid from said outlet can flow; said passage having an outlet substantially below said enclosure outlet; means for directing the abrasive material from said passage outlet toward said nozzle; and outlet means for receiving the fluid from said passage.

10. 'In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material; a'nozzle carrier; a nozzle in said car- 1 rier below said mounting means for directing a fluid upwardly through the abrasive material to blast said material upwardly against the drill bit; means mounting said carrier for movement about an axis eccentric to the 'rotational axis of said mounting means, totenable said nozzle to be shifted toward and away from said rotational axis; an enclosure above said nozzle and surrounding at least part of said rotating means and into which abrasive lladen fluid can pass upwardly after striking the drill bit,

said enclosure having an upper outlet through which the upwardly moving abrasive laden fluid can discharge; a passage through which the abrasive laden fluid from said outlet can flow; said passage having an outlet substantially below said enclosure outlet; means for directing the abrasive material from said passage outlet toward said nozzle; outlet means for receiving the fluid from said passage; and means rotatable with said mounting means for moving the abrasive laden fluid upwardly through said enclosure.

11. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material below said mounting means; said mounting means supporting the drill bit above and adjacent to the quantity 'of abrasive material therebelow in said containing means; a nozzle carrier; a nozzle in said carrier having an outlet below said mounting means for directing a fluid upwardly through the abrasive material to blast said material upwardly against the drill bit; means mounting said carrier for movement about an axis eccentric to the rotational axis of said mounting means, to enable said nozzle to be shifted toward and away from said rotational axis; an inner enclosure above said nozzle and surrounding at least part of said rotating means and into which abrasive laden fluid can pass upwardly after striking the drill bit, said inner enclosure having an upper outlet through which the upwardly moving abrasive laden fluid can discharge; an outer enclosure surrounding and spaced from said inner enclosure to provide an annular passage therewith through which abrasive laden fluid from said outlet can flow; said passage having an outlet sub stantially below said enclosure outlet; means for directing the abrasive material from said passage outlet toward said nozzle; and outlet means for receiving the fluid from said passage outlet.

12. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; a shaft secured to said mounting means and rotatable with said mounting means about a fixed axis; a turbine rotor secured to said shaft; a nozzle for directing fluid against said rotor to rotate the drill bit about said axis; means adapted to contain a quantity of abrasive material; said mounting means supporting the drill bit adjacent to the quantity of abrasive material in said containing means; and nozzle means positioned to direct fluid discharged therefrom into and through the abrasive material to impact the abrasive material against the rotating drill bit.

13. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; a shaft secured to said mounting means; a turbine rotor secured to said shaft; a nozzle for directing fluid against said rotor to rotate the drill bit; means adapted to contain a quantity of abrasive material;

said mounting means supporting the drill bit adjacent to 7 enable said jetting device to be shifted toward and away from said rotational axis.

14. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; a shaft secured to said mounting means; a turbine rotor secured tosaid shaft; a nozzle for directing fluid against said rotor to rotate the drill bit; means adapted to contain a quantity of abrasive material; said mounting means supporting the drill bit adjacent to the quantity of abrasive material in said containing means; nozzle means positioned to direct fluid discharged therefrom into and through the abrasive material in said containing means to impact the abrasive material against the rotating drill bit; an enclosure surrounding said mounting means and shaft and into which abrasive laden fluid can pass after striking the drill bit, said enclosure having an outlet for the abrasive laden fluid; a passage through which the abrasive laden fluid exiting from said outlet can flow; means for directing the abrasive material from said passage toward said nozzle means; and outlet means for receiving the fluid from said passage.

15. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; a substantially vertical shaft secured to said mounting means; a turbine rotor secured to said shaft; a nozzle for directing fluid against said rotor to rotate the drill bit; means adapted to contain a quantity of abrasive material; nozzle means for discharging the fluid upwardly and impact the abrasive material against the rotating drill bit; a generally vertical enclosure surrounding said rotating means and shaft into which abrasive laden fluid can pass upwardly after striking the drill bit, said enclosure having an upper outlet for the abrasive laden fluid; a passage through which the abrasive laden fluid issuing from said outlet can flow in a downward direction; means for directing the abrasive material from said passage toward said nozzle means; outlet means for receiving the fluid from said passage; and means rotatable with said shaft for lifting the abrasive laden fluid through said enclosure.

16. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; a vertical shaft secured to said mounting means; a turbine rotor secured to said shaft; a first nozzle for directing fluid against said rotor to rotate the drill bit; means adapted to contain a quantity of abrasive material below said mounting means; said mounting means supporting the drill bit above and adjacent to the quantity of abrasive material therebelow in said containing means; a second nozzle below said mounting means for discharging fluid upwardly to impact the abrasive material against the rotating drill bit; an inner enclosure surrounding at least part of said mounting means and shaft and into which abrasive laden fluid can pass upwardly after striking the drill bit, said enclosure having an upper outlet for the abrasive laden fluid; an outer enclosure surrounding and spaced from said inner enclosure to provide an annular passage through which abrasive laden fluid from said outlet can flow in a downward direction; means for directing the abrasive material from said passage toward said second nozzle; and outlet means for receiving the fluid from said passage.

17. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; a vertical shaft secured to said mounting means; a turbine rotor secured to said shaft; a first nozzle for directing fluid against said rotor to rotate the drill bit; means adapted to contain a quantity of abrasive material; a second nozzle for discharging fluid upwardly to impact the abrasive material against the rotating drill bit; an inner enclosure surrounding at least part of said mounting means and shaft and into which abrasive laden fluid can pass upwardly after striking the drill bit, said enclosure having an upper outlet for the abrasive laden fluid; an outer enclosure surrounding and spaced from said inner enclosure to provide an annular passage through which abrasive laden fluid from said outlet can flow in a downward direction; means for directing the abrasive material from said passage toward said second nozzle; outlet means for receiving the fluid from said passage; and an annular baifle secured to said rotor and depending therefrom between said inner and outer enclosures in spaced relation thereto.

18. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; a vertical shaft secured to said mounting means; a turbine rotor secured to said shaft; 2

first nozzle for directing fluid against said rotor to rotate the drill bit; means adapted to contain a quantity of abrasive material below said mounting means; said mounting means supporting the drill bit above and adjacent to the quantity of abrasive material therebelow in said containing means; a nozzle carrier; a second nozzle in said carrier for directing a fluid through the abrasive material to blast said material upwardly against the drill bit; means mounting said carrier for movement about a generally vertical aXis eccentric to the rotational axis of said shaft, to enable said second nozzle to be shifted toward and away from said rotational axis; an inner enclosure surrounding at least part of said mounting means and shaft and into which abrasive laden fluid can pass upwardly after striking the drill bit, said enclosure having an upper outlet for the abrasive laden fluid; an outer enclosure surrounding and spaced from said inner enclosure to provide an annular passage through which abrasive laden fluid from said outlet can flow in a downward direction; means for directing the abrasive material from said passage toward said second nozzle; and outlet means for receiving the fluid from said passage.

19. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material; said mounting means supporting the drill bit adjacent to the quantity of abrasive material in said containing means; nozzle means positioned to direct a fluid into and through the abrasive material in said containing means to blast said material against the drill hit; an enclosure surrounding at least part of said rotating means and into which abrasive laden fluid can pass after striking the drill bit, said enclosure having an outlet for the abrasive laden fluid; a passage through which the abrasive laden fluid exiting from said outlet can flow; means for directing the abrasive material from said passage toward said nozzle; and outlet means for receiving the fluid from said passage.

20. In abrasive blasting apparatus for drill bits: means for mounting a drill bit; means for rotating said mounting means and drill bit; means adapted to contain a quantity of abrasive material below said mounting means; said mounting means supporting the drill bit above and adjacent to the quantity of abrasive material therebelow in said containing means; nozzle means below said mounting means positioned to direct a fluid upwardly into and through the abrasive material in said containing means to blast said material upwardly against the drill bit; an enclosure above said nozzle means and surrounding at least part of said rotating means and into which the abrasive laden fluid can pass upwardly after striking the drill bit, said enclosure having an upper outlet through which the upwardly moving abrasive laden fluid can discharge; a passage through which the abrasive laden fluid from said outlet can flow; said passage having an outlet substantially below said enclosure outlet; means for directing the abrasive material from said passage outlet toward said nozzle; and outlet means for receiving the fluid from said passage.

References Cited in the file of this patent UNITED STATES PATENTS 624,097 Robb May 2, 1899 1,081,547 Mota Dec. 16, 1913 1,587,947 Griffin June 8, 1926 2,307,816 Zimmerman Jan. 12, 1943 2,719,387 Fahrney Oct. 4, 1955 2,813,376 Middlemark Nov. 19, 1957

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