US2151545A - Composite bit - Google Patents

Description

March 21, 1939.

J. A. ZUBLIN COMPOSITE BIT Filed July ll, 1938 l Patented Mar.' 21, 1939 "UNITED STATES PATENT oFFlcl-:L

5 Claims.

The present invention relates generally to rotary Well drilling bits such as are used to drill oil Wells and the like, and more particularly to drill bits of the general type described in my prior United States Patent Nos. 2,050,988 and 2,069,799. Drill bits of this type are provided with a. plurality of rotatable cutters mounted upon one or more carriers which, in turn, are rotatably mounted upon a shank. Because of this type of mounting the reaction of the cutters on the formation causes the carrier to rotate with respect to the shank and thereby successively and intermittently cause the rollers to contact with the formation with a rolling motion thereon. The general principles underlying the type of drill bit under consideration will be found in my Patent No. 2,050,988.

In the first mentioned patent, a plurality of carriers is used, the cutters on each carrier contacting the bottom of the hole on opposite sides of the bore axis. This arrangement prevents any of the cutters from coming into coincidence with the axis of the hole when the cutters are in their bottommost position. The second mentioned patent (No. 2,069,799) is provided with only a single carrier which is preferably inclined to the horizontal. The inclination will normally cause the bottommost roller to contact with the formation to one side of the hole axis and will thereby insure rotation of the carrier about the inclined `axis so long as the shank is being rotated.

In view of the fact that drill bits of the type under consideration form a hemispherical'bottom in the formation, drilling weight on the bit would tend to move the bottommost roller into coincidence with the hole axis. If this were to occur, rotation of the carrier in the manner aforementioned would practically cease. To overcome this possibility it has heretofore been proposed to provide a thickened leg portion on the shank which will bear against the sides of the hole and prevent the bottommost roller from moving into a position coincident with the hole axis. The thickened leg portion is an effective instrumentality for insuring carrier rotation. But it also introduces-wear on the leg caused by its thrust against the formation. It is with the end in view of decreasing or eliminating the Wear on the shank, as the leg portion thereof, and in maintaining the bottomrnost roller from coincidence with the hole axis that the present invention is concerned.

Accordingly, it becomes a general object of this invention to provide an improved drilling bit specially adapted for use in hard formations.

A further object of the invention resides in the provision of an improved bit having separated digging and reaming portions.

A further object of the invention involves a bit in which the side thrust on a shank is absorbed by reaming rollers. I

Still another object of the invention is to provide a bit wherein the bottom contacting rollers are maintained to one side of the hole axis by upper reaming rollers.

A further object of the invention lies in the provision of a bit which Will be self-stabilizing in the hole and which will prevent the production of an undergauged bore.

A further object of the invention lies in the provision of improved iiow channels for maintaining reaming rollers free from cuttings While at the same time assisting their rotation about their own respective axes. l

In the prior art constructions, roller reamin cutters have usually been disposed equidistant circumferentially of their supporting shank. When two diametrically opposite cutters are used, the reamer is capable of wobblingand possesses unsteadiness in its operation. On the other hand. when three or more equidistant rollers are used, the reamer possesses stability but has -associated with it a restricted clearance which in some instances will prevent operation of the tool, as when it is necessary to pass through collapsed casing.

Accordingly, it becomes a further object of this invention to provide a rotary reamer that is more stable in operating in the bore hole.

A further object of the invention involves a rotary reamer having increased clearance, rendering it more readily passable through a bore hole or casing.

Still another object of the invention involves A a nonuniform disposition of roller reaming cutters around the circumference of the shank to provide a bit possessing stability in its operation and capable of producing a full gauge hole.

How the above and other objects and advantages of my invention are secured will be better understood by reference to the following descrintion and the annexed drawing in which:

Figure 1 is an elevation of the composite bit with parts thereof 'being shown in section;

Figure 2 is a side elevation of the drill bit as seen from the right of Figure 1;

Figure 3 is a section along the line 3-3 of Figure 1; and

Figure 4 is a view similar to Figure 3, on a reduced scale, showing a modified form of reamer. I

In general, Vthe drill bit includes a lower cutting portion A and an upper reaming portion B. The former is substantially the same as that described in my copending application entitled Compact bits flied February 21, 1938, Serial No. 191,622. Inasmuch as it is not by itself being claimed in this application the various parts and the advantages of the arrangement shown will not be described in particular detail.

The lower portion of the bit includes a plurality of depending legs II, I2 extending from the shank body I0, the upper end of which carries the usual threaded pin I3 for connecting the drill bit with the drilling string. One of the legs iI has i'ormed integrally therewith a bearing supporting member I4 adapted to carry a cutter assembly C, to be described hereinafter. The end of the bearing supporting member I4 is provided with a reduced extension I5 tting into a bore I5 formed in the leg I2 of the shank, which leg, after the cutter assembly has been placed on the bearing supporting member, can be welded at its upper end I2a to the shank body proper and at its lower region I2b to the reduced extension I5. 'Ihe cutter assembly includes a cutter carrler I1 provided with a plurality of circumferentially spaced slots I8 which are bridged by bearing pins I8 welded to the side portions 20 of the slots, each pin carrying one or more formation contacting rollers 2l. 'I'he carrier I1 is provided with a plurality of ball bearing raceways 22 in an innerfbore 23, which are adapted to cooperate with an inner bearing race 24 containing complementary toric raceways 25. Between the raceways are provided balls v`26 which will serve to transmit bearing loads between the carrier and inner race.

Prior to the placing oi the separate long leg I2 the reduced bearing supporting extension I5 and its welding thereto and to the shank body, the carrier I1 with the cutters 2| and pins I9 thereon is placed over the inner race 24 and the bearing balls 2i introduced into the raceways 22, 25 through the holes 21 formed within the inne-r race and communicating with respective raceways. Thereafter, buttons 2l having an upper cylindrical portion 23a and a lower rectangular portion 23h are inserted into the bores, serving to prevent the balls from falling from the raceway while at the same time providing a substantially continuous raceway on which the balls can roll as the carrier rotates. The lower portion 28h of the buttons is made rectangular in shape so as to be capable of riding in the keyway 29 formed in the bearing supporting member, and thus serving to lock the inner race 24 from rotation with respect to the bearing supporting member I4. As explained in my application above referred to, the buttons serve the three-fold function of providing a substantially uninterrupted raceway,l preventing the balls from falling from the raceway, and keying the inner raceway to the bearing supporting member.

Upon assembly of the carrier I1 on the main bearing and the insertion of the buttons 28 in the manner aforementioned, this entire assembly is slid over the bearing supporting member with the rectangular button heads riding in the keyway. Thereafter, the long leg I2 is placed over the reduced extension I5 with the boss 30 on the leg abutting the end4 of the inner race, and causing the opposite end of the race to abut against the boss 3l formed on the other leg II extending from the shank. Upon welding the upperpartoftheleg ilatotheshank lilandthe lower part to the reduced extension I5, a rigid shank assembly results for carrying the cutter assembly for rotation with respect to the shank about an inclined axis D-D with the bottommost roller 2Ia positioned to one side of the axis E-E of the hole.

As described in my copending application, an upper nozzle 32 is placed in the shank communieating with and receiving drilling fluid from the passageway 33 provided in the shank. The nozzle will effect a discharge of iluid against successive cutters as they pass under it, the force of the ilud rotating each cutter about its own axis to insure that all of the teeth or cutting edges are eiiectively cleaned. 'Ihe cuttings are removed from the bottom of the hole by discharge of fluid from a nozzle 34 threadedly held in the lower portion of the leg II which has a conduit 35 therein for establishing communication between the shank passageway 33 and the nozzle 34. The fluid will issue from this lower nozzle and sweep transversely across the hole bottom for effectively removing the detritus.

The upper portion B of the bit constitutes a reamer. A plurality of slots 36 is formed in the shank body with the ends of each slot terminating in a plurality of notches or grooves 31, each of which receives a bearing pin 38. Each bearing pin carries one or more reamer roller cutters 39a, 39h having teeth thereon, although, if desired, disc or other cutters can be used. The rollers in each set are mounted upon their pin, which is then inserted in the notches 31 of the shank. The ends of the pins are welded in the groove to eect a rigid attachment of the pins to the shank body while permitting free rotation of the rollers on the pins. In the specific illustration shown in Figures 1 and 3 a set of rollers is provided on one portion of the shank, being balanced by a substantially diametrically opposite single roller. However, the number of rollers may be varied without departing fromv the scope and spirit of the invention relating to the combination of the lower cutting portion and reaming portion. y

One of the main features of the invention resides in positioning the rollers 39a at the right of the drill bit (as seen in Figure 3), so that by their contact with the formation they will maintain the bottommost rollers 2Ia at the lower portion of the bit from coincidence with the hole axis. That this will occur will become apparent from a mere inspection of Figures 1 and 3. As the drilling tool rotates, the reaming rollers will move around on the formation, maintaining the hole to gauge, and because of their engagement with the sides of the hole will position the bottommost rollers 2Ia to the side of the hole axis opposite to the position of the reamer rollers. It will be noted further that the shank leg I2 is spaced from the sides of the hole, and will be maintained in the spaced position by the engagement of the upper reamer rollers 39a with the formation throughout substantially the entire drilling life of the tool. This will prevent wear from occurring on this leg, or decrease the wear. Similarly, Wear upon the other leg I I depending from the shank will be prevented by the other set of rollers 39h which, by their contact with the sides of the hole, will maintain this leg spaced from the formation.

As stated before, the number of reamer rollers can be varied. Thus, even a single roller, or a single set positioned on that side of the hole axis opposite to the position of the bottommost hole contacting roller 2|a will maintain such contacting position and eliminate wear upon the long leg l2 depending from the shank. Moreover, one or more larger or smaller diameter reamer rollers can be used to alter the contact position of roller 2m as regards the hole axis, and also to change the nal diameter oi the bore.

The reamer rollers are kept free from cuttings by the incorporation of a plurality of nozzles 40a., 40h threaded into the shank and communieating with the passageway 33 in the shank body. Fluid will issue from the small nozzles and engage againstall parts of each roller cutter sinceA each cutter will rotate about its bearing pin and during this movement will position all of its cut-` ting parts in the path of the stream issuing from the nozzle. Each nozzle is positioned so as to direct its discharge to one side of the axis of 'the roller upon which it acts in the direction roller about its axis and at the same time thoralone.

oughly flushes all cutting parts thereon.

Apart from its novel mode of operation in conjunction with the lower cutting portions of the drilling tool, the reamer arrangement shown possesses certain advantages when considered It will be noted that the rollers 39a are adjacent one another circumferentially of the shank, and that the roller 39h is substantially diametrically opposite the first named pair. By this arrangement an increased clearance betweenv the shank and the walls ofthe bore and easing can be had when compared with a reamerconstruction in which three rollers are spaced equidistant circumferentially of the shank. or 120 apart; or when compared with equidistant spacing of more than three cutters. While the use of two diametrieally-opposite rollers is known,.

such types of reamers are unstable since they can oscillate or wobble about a line passing through their contacting positions with the formation. The arrangement disclosed in Figure 3 not only provides an increased clearance, but also stabilizes the tool by virtue of its threepoint contact with the Walls of the hole.

The modification disclosed in Figure 4 also provides stability and an increased clearance, although not to so great an extent as the Figure 3 construction. In Figure 4, four rollers are disclosed. But instead oi being disposed equidistant eircumferentially oi the shank, or apart, the rollers 39a are moved toward one another so as to occupy circumferentially adjacent positions on theshank. The other rollers 39h occupy a. position of substantially 90 with respect to one another, their median plane being placed substantially diametrically opposite the median plane of the rollers 39a. vAs a result,

. the'eircumferential distance between the rollers This application is a continuation in part of my application Serial No. 19l,6v2l, led February 21, 1938, Composite bits.

While the invention has been described with particular reference to the embodiment shown on the drawing, it is to be understood that changes may be made in its construction and arrangement of parts Without departing from the intent and scope of the invention, and consequently, the foregoing description is to be considered illustrative of rather than restrictive upon the claims appended hereto.

l. A reamer comprising a shank, a pair of roller reaming cutters on the shank, the cutters of said pair being in adjacent relation ciroumf dit cutters in adjacent relation circumferentially of rearning cutters on the shank opposite said first4 pair and spaced a greater circumferential distance apart than said mst-mentioned pair.

4. A reamer comprising a shank, one or more 4 roller reaming cutters on the shank, a uid passageway in said shank, and fluid discharge means communicating with said passageway andarranged on the shank to direct its discharge against the reaming cutter to one side of its axis whereby to urge its rotation.

5. A reamer comprising a shank, a roller reaming cutter on the shank, a fluid passageway in the shank, and a nozzle positioned on the shank so that the fluid discharge therefrom will be directed against the cutter to one side of its axis whereby to urge its rotation.

` JOHN A. zumm.

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