US2248340A - Rock bit - Google Patents

Description

Patented July 8, 1941 Roon Brr Aurea o. canaria, Alhambra, Calif., assignorco Globe Oil Tools Company, Los Nietos, Calif., a corporation of California Application July 26, 1940, SerialI No. 347,704

(Cl.A Z55-71) 14 Claims.`

This invention relates to well drilling tools and relates more particularly to bits for use in the rotary method of well drilling. A general object of the invention is to provide a rotary rock bit of improved constructionthat is easy to assemble, that is dependable in operation and that is long wearing. L f, i

Another object or this invention is to provide a rock bit that is simple and inexpensive to manufacture, requiring a minimum of machining and involving a minimum waste of materials.

Another object of this invention is to provide a' rock bit embodying novel means for rotatably mounting the outer cutters in which the customary bushings are eliminated permitting the use of large diametered supporting pins hav ing larger cross sections to resist shearing forces, presenting large wear taking surfaces and forming stronger ties between -the body legs of the supporting web structure. v

Another object of this invention is to provide a rock bit including improved means for mounting -the inner roller cutters that allows the use` of cutters of heavier wall thickness or cross section so that long wearing. deep cutting teeth may be formed in the cutters that adapt the bit for luse in sticky shales and soft earth formations that quickly pack onto and mud up the shallow cutting teeth of typical cutters.

Another object of this invention is to provide a rock bitembodying a novel assembly, comprising the several cutters and the cutter support,

body to directly bear on the same and that is 'integrally joined with the bit body by easily formed and readily accessible welds.

Another object of this invention is to provide a rock bit oi the character referred to in which the inner and outer cutters are supported by anti-friction bearing means which support them against both radial and axial thrusts, said bearingr means being sturdy, long wearing and require a minimum of expensive machine work. 4

The various objects and features of my invention will be fully understood from the following detailed description of typical preferred lforms and applications of my invention, throughyin vertical cross section. Fig. 2 is a-fragmentary vertical detailed sectional view taken as indicated by line .2--2 on Fig. -1. Fig. 3 is a fragmentary vertical detailed sectional view oi the lower portion of the bit taken in a plane at right anglesl to the plane o! sectioning of Fig. '1, illustrating the youter. cutters and the outer cutter mounting means, and Fig. 4 is a fragmentary vertical de-y tailed sectional view showing an: alternative means for mounting the outer cutters.

The improved rotary rock bit 'of the present invention may be said to comprise, generally, a body I0, inner and outer cutters II and I2, a supporting member I3, means I4 for rotatably mounting the inner cutters II and means I5 for rotatab y mounting the outer cutters I2.

The bit body III is adapted for attachment to f the lower end ol' a rotary well drilling string and serves to carry the various other parts of the tool. The bit body- I0 is provided with means for facilitating its attachment to the drilling string. In .practice this may be a tapered screw threaded pin I6 projecting from the upper? end of the body I0. A central vertical fluid passage I1 enters the body I0 from the upper end of its pin I6 and spaced discharge ports I8 lead from the lower 'end ofthe passage I1 to the under side of the body. A pair of diametrically opposite legs I9 projects downwardly from the lower end of the body I0. The upper parts of the legs I9 slope f or curve outwardly and downwardly while the lowerparts of the legs are substantially vertical. Flat vertical faces 20 are formedon the in- 'that is easily and quickly arranged on the bit ner sides of the straight, vertical lower partsy ol' the legs I9. A second set or pair of legs 2I xprojects from the lower end ofthe body I0. The legs 2l are spaced-between the legs I9, there being substantially 90 between the vertical centers of the adjacent legs i9 and 2l. The legs 2i project downwardly and outwardly from the body I0 having downwardly and outwardly-sloping inner sides. Flat finished faces 22 are formed on the sloping inner sides of the legs 2|.' Slots or notches 23 extend upwardly in the legs I 9 from the lower ends of the legs and lateral or radial openings 24are provided in the legs 2i. The longitudinal axes of the openings 24 slope downwardly and inwardly. being substantially normal to the faces 22 and the outer parts of the openings 24 are iiared.

The cutters il are the inner cutters of the bit operating to cut away the earth formation in the inner part of the well bore. There are two like or similar inner cutters II. As illustrated in Fig. 1 the cutters I`Il are elongate frusto-conical members provided at their peripheries with suitable cutting teeth 25. The opposite ends of the cutters II are hat and normal to the cutters long axes and central longitudinal openings 28 extend through the cutters from. one end to the other. The openings 28 are enlarged in diameter in the outer parts oi' the cutters, there being cylindrical recesses or sockets 21 leading into the cutters from their outer ends. While the openings 28 are of `substantial diameter the cutters II are formed to have heavy or thick .walls particularly at--their inner parts. 'I'his allows the formation of deep cutting teeth 28 which are particularly adapted for use in sticky shale and relatively soft earth formations. The tapered Y or frusta-conical cutters Il are arranged with their .small ends facing inwardly adjacent the central vertical axis of the tool.

The outer cutters I2 are provided to form the outer portion of the well bore and to cut the bore to size or gauge. There are two cutters I2 of substantial diameter. 'I'he cutters |2 are alike and are preferably frusta-conical, having slightly pitched peripheries. The ends of the cutters I2 may be fiat and parallel and central longitudinal openings 28 of substantial diameter extend through the cutters from one end to the other.

The cutter openings 28 have outer parts of increased diameter providing outwardly facing annular shoulders 28 on the interiors of the cutters. The enlarged portions of the openings 28 are of considerable depth or length. Suitable cutting l teeth 38 are formed on the peripheries ofthe outer cutters I2. 'I'he corners of the cutting teeth 38 are preferably bevelled oil'.

broad sides opposing or facing the legs I8 and downwardly 'and outwardly sloping edges 3| facing the inner sides of the legs 2|. A stem 32 extends upwardly i'rom the member I3 and has a flat upper face for bearing on a substantiallyI horizonal surface 34 on the lower end of the body I8. A weld 38fintegrally joins the stem 32 with the body I8.- The sloping edges 3| of the web I8 have raised finished faces 38 opposing and parallel with the finished faces 22 of the legs 2|. Integral lugs or extensions 31 protrude from the faces 38. 'I'he extensions 31 are cylindrical and project upwardly and outwardly being substantially concentric with the pitched openings 24 in the legs 2|. A horizontal opening 38 is provided in the lower portion of the member I3. The-longitudinal axis of the opening 33 lies in a central vertical plane of the body |8 and is coincident with the common longitudinal axes of the notches 23. Raised parts or bosses 38 are provided on the opposite sides of themember I3 in surrounding relation to the opening 38.

The means forrotatably mounting the inner cutters II supports the cutters on the member I3 and the body legs I8 for free independent rotation about a horizontal axis. 'Ihe cutters II 'are arranged between the legs I8 and the member I3 in aligned relation withtheir longitudinal axes coincident with the axis of the opening 38. The means 4 includes a pin ,48, extending through the opening 38 and passing through the cutter openings 28 to project into the notches 23. The/ central portion of the pin 48 is of increased 75 diameter and is closely received in the opening 88. The enlarged intermediate portion of the pin 48 extends from the opposite sides of the 4member |3 projecting a substantial distance into the cutters Il.l The enlarged portion of the pin 48 stiifen's and strengthens the pin where it is supported on the member I3. Flat outwardly facing shoulders 4| occur4 on the pin 48 at the .ends of its enlarged intermediate portion.. The pin 48 passes outwardly through the openings 28 of the cutters with substantial clearance. The pin 48 terminates within the notches 23 having its ends spaced from theouter sides of the legs I8.

'I'he means I4 for supporting the inner cutters further includes bushings 42 arranged on the end portions or the smaller portions of thel pin 48. The inner ends of the bushings 42 are en-y gaged against the shoulders 4I while the outer ends of the bushings, are at or adjacent the ends of the pin 48. 'I'he bushings 42 are graduatedk or stepped in external diameter, the inner portions of the bushings being the largest in diameter, the intermediate portions being somewhat reduced in diameter providing outwardly facing annular shoulders 43 and the end portions of the bushings being further reduced in diameter providing second outwardly facing shoulders 44. The inner shoulders 42 are located adjacent but outward of the shoulders 48 which occur in the cutters Il at the inner ends of the sockets 21. The second or Vouter shoulders 44 of the bushings 42 are adjacent the ends of the cutters II.

A ball race 48 is provided in the large inner portion of each bushing 42 and a mating or opposing race 41 is provided in the wall of the sur lugs 8| on the plugs 88 cooperate with keyways or notches 82 in the inner walls of the bushings 42 to hold the plugs 88 against `turning and to prevent outward movement of the plugs. 'I'he plugs 88 are shaped so that their outer ends form unbroken continuations of the racesf48.. It will be seen that the balls48 engaged in the mating races 48 and 41 assist in transmitting radial loads and hold the cutters I| against axial move-y ment in both directions.

In addition to the ball bearing means just described the cutter mounting means I4 includes roller bearings for mounting the cutters I I on the pin 48 and the bushings 42. Series of anti-friction rollers 88 are arranged in the inner portions of the cutters II between the bosses 38 and the inner ends of the bushings 42. The bosses 38 and the bushings 42 operate to hold the rollers 83 against axial displacement.- It will be observed that the rollers 83 are engaged on the large di\ ametered intermediate portion of the pin 48 and are directly received in the cutter openings .28. Second sets of rollers 84 are arranged in the sockets 21 in the outer parts of the cutters to bear r88 may be shaped to enter the sockets 21 and engage against the shoulders 44. Theoutward axial movement of the rollers 54 is limited by the washers 55. The washers 55 in addition to limiting outward movement of the rollers I54v prevent the cutters II from wearing against the legs I9. 'I'he opposite end portions of the inner roller cutters II are dependably supported by thesets of 340 v on the largel diametered pins 64 by the rollers 69.

In accordance with the invention elements of the means I4 for mounting the inner cutters II and elements oi.' the.means I6 supporting the outer cutters I2 are integrally joined with v body parts to tie the various elements together anti-friction rollers 53 and 54 and the series of balls 46 are spaced between the sets of rollers to assist in mounting the cutters and to assume end thrusts in both directions. v

The means I5 for supporting the outer cutters I2 mount the cutters I2 between the legs 2l and the faces 36 to have independent rotation about downwardly and inwardly inclined axes..-

ings 56 to the races 51 to'facilitate the insertion of the balls 59 into the races 61 and 58. vPlugs 6l occupy the openings Wto-retain the balls 59 in the races. The outer ends of the plugs 6I are shaped to conform tothe walls of the races 5l. Keys or lugs t2 on the inner ends of 'the plugs 6I cooperate with keyways 69 in the bushings 56 to hold the plugs 6I against turning and outward movement. The balls 59 engaged in the races 51 and 58 assist in. rotatably supporting the cutters I2 and assume or transmit end thrusts in both directions.v

'I'he means l 6 for rotatably mounting the outer cutters I2 further include shafts or pins 66 se-` cured to the extensions 31 of the member I3.

The pins 64 are larger in diameter than the extensions 31 and their inner ends engage against the outer ends of the bushings 56 to positively hold the bushings against endwise movement.

In accordance with the invention the pins 69 are threadedly secured to the extensions 31. In the construction illustrated reduced stems 65 on the inner ends oi the pins 64 thread into sockets 66 in theextensions 31 to attach the pins to the extensions. The pins 64 extend outwardly to the body legs 2i and are received in the openings 24. In the form of the invention illustrated in Fig. 3 heads 61 of enlarged diameter are provided on the outer ends of the pins 64 and t the inner parts of the openings `24. The

inner sides of the heads 61 form inwardly fac#- ing shoulders 68. These shoulders 68 lie in planes adjacent and inward of the faces 22 on the v inner sides of the legs 2I.

ends of the rollers69 may engageagainst the bushings 56 to prevent or limit inward movement of the rollers. The shoulders 68 operate to limit or prevent outward movement of the rollers 69 and prevent the rollers from rubbing 'and to dependably mount the several cutters.

Welds 10 are provided in the slots or notches -23 to Vintegrally'join the bushings 42, the pin .40 and washers 55 with the body legs I9. The opposite ends'of the pin 40 are exposed at the ends of the bushings 42 so that the welds 1I) connect the pin and bushings and join the pin and bushings with the body legs I9. The welds 10 may fully occupy the portions of the slots or notches 23 not occupied by the bushings 42 and the pin 49. As shown in Figs. l and 2 of the drawings, the upper sides of the bushings 42 may directly bear against the walls of the slots o r notches 23 and the welds 19 may extend across the outer ends of the bushings 42 and the pin 40 and may fully occupy the lower portions of the notches 23.. I t will be observed that the welds 1U are freely accessible to be readily ,formed and to be ground off or iinished flush with the faces of the legs I9. The pins 64 which are threadedly connected tothe extensions- 31 of the member I3 are integrally joined with the body I0 by welds 1I in the openings 2d.. The heads 61 of the pins 64 t or engage in the innew parts of the 'openings 24 and have their outer ends spaced from the mouths or outer ends of the openings, leaving ample spaces for the welds 1I. Reduced stems 12 may extend outwardly from the pinv heads 61. The welds 1i may fully occupylthe portions of the openand wearing against the faces 22 of the body ings 24 not occupied by the head 61 and the stems 12. The outer ends of the welds and the stems 12 may be ground oi or finished iiush with the outer faces of the legs 2I. The welds 1l integrally connecting the pins 64 and the legs 2i of course preventunthreading of the stems 64 from the sockets 66 and connect the pins with the body I0 so that the pins form ties gtwegen the body legs 2I and the support mem- Fig. 4 of the drawings illustrates a slightly modiiied means for rotatably mounting the outer cutters I2. In this construction the bushings 56, the rollers 69, the extensions 31, the ball bearings .1.59 and the stems 65 are the same as in the previously described form of the invention. 'The structure of Fig. 4 differs from the construction illustrated in Fig. 3l in that -the v pins 648 are devoid of the heads 61. 'The pins the openings 24l to join the pinsf f=6tanitthee` body legs 2I. In this construction the faces 22 of the body legs 2| serve to limit outward axial lshifting of the rollers 69- In assembling the bit the pin 49 is arranged in the opening 38 of the support member I3 to have portions of equal length project from theopposite sides of the member. The bushings 42 are inserted in the cutters II and the balls 48 are passed through the openings 49ito occupy the races 46 and 41. lThe plugs 50 are then arranged in the openings 49 to retain the balls. The outer sets of vrollers 54 are assembled in the cutters II and the inner rollers 53 are asjj. v.

sembled about the enlarged portion of the pin 4U. The washers 55 are arranged against the outer sides. of the cutters II andthe cutters are slid onto the pin 4I). If desired the cutters II may be partially engaged -on the pin 40 prior to assembling the rollers Il on the pin. It is 'to be understood that the cutters II with their bearing elements may-be individually assembled 'on the pin 40. v

' The outer cutters I2 are then prepared for arrangement on the member I3.` 'Ihe bushings 56 are inserted in the cutters I2 and the balls 59 are passed through the openings 60 into the races 51 and 56 whereupon the plugs 6I are arranged to close the openings 60. JT'he cutters I2 containing their bushings 66 are placed onthe extensions 31 and the rollers 63 are arranged'in the cutters toA engage against the bushings 56. Heavy grease i. may -be placed around the rollers 6 9 to retain them in position.

The assembly of the member I3 andthe four `sockets 68 so that the pins are securedv to the member I3 and pass through the series of-rollers 69. With the assembly of the cutters and their supporting member I3 in the proper position the assembly is fixed in this position by welding the stern 32 to the body III at 35, and forming the welds 'I3 and 1I. 'I'he welds 'Ill and 1I are easily reached with the welding rod and are readily accessible to be finished or smoothed off whencompleted. The weld 35 is substantially hidden from view and it is unnecessary to grind or iinish it.

It is to be understood that the wear receiving surfaces of the cutters II and I2, the pin 46, the bushings 42, the bushings 56 and the pinsy 64 and 64B may be provided vwith hard wearresisting surfaces. The body legs I9 and 2l may be heat treated to be tough and shock resistant. It is to be particularly noted that the'hard surfaced pins 64 are integrally joined with the heat treated legs 2l so that hard surfaced cutter supports are .provided on the shock resistant body legs. The pins 64 and 64 are of large diameter,

on its lower end, the lower part of each leg having an opening, a support member spaced between the legs and having a( transverse opening aligned with the openings inthe legs, a generally horizontal one piece pin having an intermediate portion of increased diameter bearing in said opening in the supportmember and having its end portions extending vinto the openings in the legs and rigidly xed to the legs, and roller cutters rotatably mounted on the pin between the support member and the legs. Y

2. In a rock bit, a bit body having spaced legs on its lower, end, a support member spaced between the legs and having a transverse opening,

a generally horizontal pin having an intermediate portion of increased diameter bearing in said ropening and having its ends fixed to the legs,

cutters II and I2 is then placed on the body II) i support and projecting outwardly therefrom to forming strong ties between the member I3 and the body legs 2I which have large areas or cross sections to resist shear stresses. The direct engagement of the rollers 53 with the pin 40 permits 'the employment of inner cutters II of in- 1 creased wall thickness, particularly at the inner dependable and long wearing.

Having described only typical preferred forms and applications of my invention, I do not wish to belimited or restricted tothe specific details herein set forth, but wish to reserve to myself any variations or modications that may appear to those skilled in thel art or fall within the scope of the following claims.v

Having described my invention, I claim: 1. In arock bit, la bit body havingspaced legs vsecond pair of diametrically opposite legs projecting from the body and spaced between the firstlegs, a support member projecting down- -wardly from the lower end of the body and having av transverse opening aligned with the first legs, a one piece pin bearing in said opening and projecting from opposite sidesv thereof to the first. legs, vmeans fixing the pin to the first legs, inner roller cutters rotatably mounted on the pin, pins threadedly secured to the support and projecting outwardly therefrom to said second legs, and

outer roller cutters rotatably mounted on the secl ond mentioned pins.

4. In'a rock bit, a body, a rst pair of diametrically opposite legs projecting from the body, a second pair of diametrically opposite legs projecting from the body and spaced between the first legs, a support member secured to the body to project from the lower end thereof and having .a transverse opening, an integral pin having an intermediate portion of enlarged diameter bearing in said opening, the pin projecting from opposite sides of the support member to the first legs, inner roller cutters rotatably mounted on the pin, bearing pins threadedly secured to the said second legs, welds integrally joining the rst named pin with said rst legs, welds integrally joining said bearing pins with said second legs,

and outer roller cutters rotatably mounted on the j second mentioned pins.

5. In a rock bit, a body having a pair of substantially diametrically opposite legs, a support member projecting downwardly from the lower end ,of the body and spaced between the legs, bearing pins threadedly secured to the member and. projecting outwardly to the legs, welds integrally joining the bearing pins with the legs whereby the pins serve to tie the legs and member together, and roller cutters rotatably supported on the bearing pins. Y

6. In a rock bit, a body having a pair of substantially diametrically opposite legs, a support member at the lower end of the body between the legs, extensions on opposite sides of the member projecting upwardly and outwardly toward the legs, pins threadedlysecured to the extensions and extending upwardly and outwardly to member at the lower end of the body between the Y member at the lower end of the body between thelegs, extensions on opposite sides of the member projecting upwardly and outwardly toward the legs,l pins threadedly secured to the exten-` sions and extending. upwardly'and outwardly to the legs, welds securing the pins to the legs, the pins being larger in diameter than the extensions, roller cutters around the extensions and larged heads on the pins, anti-friction velements rotatably supporting the cutters on the pins. bushings on the extensions, and anti-friction elements rotatably supporting the cutters on the bushings.

8. In a rock bit, a body having a pair of substantially diametrically opposite legs, a support member at the lower end of the body between the legs, extensions on opposite sides ofthe member projecting upwardly and outwardly toward the legs, pins threadedly secured to the extensions and extending upwardly and outwardly to the legs, welds securing lthe pinsvto the legs, the pins being larger in diameter than the extensions, roller cutters around the extensions and pins, anti-'friction elements rotatably supporting the cutters on the pins, bushings on the extensions held between the support member and the inner ends of the pins, and anti-friction elements rotatably supporting the cutters on the bushings for the transmission ofl end thrusts in both directions.

9; In a'rock bit, a body having a pair of substantially diametrically opposite legs, a support member at the lower end of the body between 1 the legs, socketed extensions formed integral with the member and projecting outwardly and upwardly therefrom toward the legs, the legs having openings aligned with the extensions, pins passed through the openings and threaded into the extensions to be fixed thereto and to have engagement in the openings, welds in the openings integrally joining the pins and legs, roller cutters around the extensions and pins, and means mounting thel roller cutters on the .pins and extensions.

l0. In a rock bit, a body having a pair of substantially diametrically opposite legs, a support member at the lower end of the body between the legs, integral extensions on the opposite sides of the member, thelegs having openings aligned larged heads on the pins received in the openwith the extensions, pins passed in through the openings andthreaded with the extensions, en-

ings, bearing means on the extensions and pins between theheadsand legs, and lroller cutters rotatably carried bythe bearing means.

.1`1. In a rock bit, a body having a pair of substantially diametrically opposite legs, a support legs, integral extensions on the opposite sides of the member, the legs having openings aligned with the extensions, pins passed in `through the openings and threaded with the extensions, en-

pins received in the openings, welds in the openings integrally joining the heads with the legs, bearing means on the extensions and'pins between the heads and less, and roller cutters rotatably' carried by the bearing means'.

12. In a rock bit, a bit body, ay pair of sulo'` stantially diametrically opposite legs-on the lower end of the body, the lower. ends of the legs having notches, a support projecting from the lower end of the body and spaced between the legs,

the support having a transverseopening, a subnotches, a support projecting from the lower' end of the body and spaced `between the legs, the support having a transverse opening, a substantially horizontal pin having an intermediate portion of enlarged diameter received' in said opening, the end portions of the pin extending into said notches, bushings on the pin having their inner ends engaging against the ends of said enlarged intermediate portion and having their outer portions extending into the notches, welds atthe notches integrally connecting the bushings with the legs, roller cutters, and anti-friction means rotatably mounting the cutters on the bushings and pin.

14. In a rock bit, a. bit body, a pair of sub stantially diametrically opposite legs on the lower end of the body, the lower ends of .the legs having notches, a support projecting from the lower end of the body and spaced between the legs. the support -having a transverse opening, afsubstantially horizontal pin having an intermediate portion or enlarged diameter received in said opening, the end portions of the pin extending into said notches', bushings Ion, the pin having their inner ends engaging against the ends of said enlarged intermediate portion and having their outer portions extending into the notches, welds at the notches integrally connecting the bushings with the legs, shoulders on the bushings facing the inner sides of the legs, washers on the bushing between the shoulders, and the inner sides of the legs, roller cutters. and bearings on .the bushings and pin between the member and the legs rotatably supporting the cutters.

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