US2170320A

US2170320A - Rock bit

Info

Publication number: US2170320A
Application number: US119615A
Authority: US
Inventors: Alfred C Catland
Original assignee: Globe Oil Tools Co
Current assignee: Globe Oil Tools Co
Priority date: 1937-01-08
Filing date: 1937-01-08
Publication date: 1939-08-22
Anticipated expiration: 1956-08-22

Description

Aug.` 22, 1939.

A.C.CATLAND Rocx BIT Filed Jan. 8, 1937 2 SheetsSheet 1 H16' HIZO/wey Aug. 22, 1939.

A.,c. cA'rLAND Rocx BIT Filed Jan. a, 1957 2 sheets-sneet'z Peiented Aug. 22,-'1939 UNITED STATESA PATENT OFFICE ROCK BIT corporation of California Application January 8, 1937, Serial No. 119,615

9 Claims.

This invention relates to well drilling .tools and relatesv more particularly to a rock bit for use in the rotary method of well drilling. A general object of this invention is to provide a practical dependable rock bit embodying novel anti-friction mountings for the cutters.

Another object of this invention is to provide improvements in the type of bit construction described and claimed in my co-pending application entitled Well bit cutter mounting, Serial No. 102,527, led September 25, 1936, now Patent No. 2,111,753, granted March 22, 1938.

' Another object of this invention is to provide' a well bit embodying linner roller cutters and Il long wearing anti-friction bearing means rotatably supporting the inner cutters.

Another object of this invention is to provide a rock bit of the character mentioned in which the bearing means for supporting the inner cutters dependably supports the inner cutters against end thrusts in both directions to prevent the development of end play and excessive wear 'on the end surfaces of the cutters.

Another object of this invention is to provide a rock bitof the character mentioned in which series of balls rotatably support the inner cutters against radial thrusts and end thrusts in Aboth directions, assuring free rotation of the cutters and preventingend wear and play of the cutters.

Another object of this invention is to provide an anti-friction mounting for the roller cutters of a well bit in which separate series .of balls A a roller cutter mounting in which the cutter sup' porting pin and the bushings are prevented from chattering and hammering one against the other. Another object vof this invention is to'provide a rock blt embodying novel and improved means for removably securing the inner cutter assembly to the shank or body of the bit.

A further object of this invention is to provide a rock bit of the character mentioned in which the inner cutter assembly comprising the several inner'cutters, the bearings and the supporting pin may be installed and removed as -a unit- 'I'he various objects and features of my invention will be fully understood from the following -10 detailed description of a typical preferred form and application of the invention, throughout which description reference is made tothe accompanying drawings', in which:

Fig. 1 is a side elevation of the bit provided by @this invention illustrating the principal lower p (Cl. Z-71) portion in vertical cross-section to show the mount-.ings of the outer cutters and Fig. 2 is a side elevation of the bit-with Ithe lower principal portion in vertical cross-section to illustrate the mountings ofthe inner cutters. 6

The improved well bit of the present invention includes, generally, a shank or body I0, outer cutting means II on the body I0 and inner cutting means on the body comprising a shaft or pin I2 removably secured to the body I0, two sets or l0 pairs of cutters I3 and I4 and bearing means I5 rotatably supporting the cutters I3 and I4 on the pin, I2.

The shank or body I0 of the bit is intended to be connected with the lower end of a rotary well 'lo drilling string. In practice the body II) may be an integral member, as illustrated. A tapered screw threaded pin I6 may be provided on the upperend of the body I0 to facilitate its connection with the rotary drilling string. A sub- 20 stantially central web I'I projects downwardly from the lower end of the body IU and carries two downwardly and outwardly projecting wings I8. Outer wings I9 project downwardly and outwardly from the body I0 in spaced substantially 25 parallel relationJ to the wings I8. The outer lower corners 20 of the wings I9 are cut off to be substantially vertical. The body I0 further includes two diametricall'y opposite legs 2| 'projectlng downwardly from its'lowr end. The legs 30 2| are spaced substantially 90 from the wingsA I 9 and their lower portions are substantially vertical being only slightly pitched downwardly and outwardly. A central vertical fluid passage 22 enters the body I0 from the upper end of its pin 35 ,\I6. The lower end of the passage 22 vjoins a chamber 23 in the body Ill.- Discharge ports 24 are provided in the lower wall of the body I0 to discharge the fluid downwardly from the chamber 23 against the cutters. Replaceable wear taking 40 nozzles or beans 25 line the ports 24.

The outer cutting-means II include outer cutters 26 rotatably supported between the pairs of wings I8 and I9 to act on the outer portion of the well bore to cut the bore to gauge. The ut- 45 ters 26 are in the nature of roller cutters and may be slightly conical as illustrated. Suitable peripheral cutting teeth 21 are provided on the cutters 26.` The outer ends of the teeth 21 are bevelled 4off to be substantially vertical as the 5b n teethvcome into engagement with the formation atl the bottom of the well bore. Each cutter 26 is provided with a central longitudinal opening 28. l

The outer cutting means II furtherinclude 55 pins 29 passed outwardly through openings 38 in the wings I8 to have their outer portions threaded in openings 3| in the wings I9. The pins 29 have suitable heads at their inner ends bearing outwardly against the inner sides of the wings I8. Plain or unthreaded parts may be provided on the outer ends of the pins 29 and these parts may be peened into notches 32 in the outer sides of the wings I9 to prevent unthreading and displacement of the pins. The openings 3U and 3| are inclined downwardly-and inwardly relative to the vertical axis of the bit so that the pins 29 extend at substantially right angles to the opposing surfaces of the wings I8 and I9.

The pins 29 of course extend through the openings 28 of the cutters 26 and each pin carries a pair of

bushings

33 and 34. The opposing ends of the

bushings

33 and 34 preferably abut. The inner ends of the bushings 33 bear inwardly against the wings I8 while the outer ends of the bushings 34 bear outwardly against the wings I9. Lugs 35 are provided on the bushings 33 to cooperate with the lower ends of the wings I8 to prevent turning of the bushings and to assist in transmitting thrusts from the bushings to the wings. Each bushing 33 is provided at its inner end with a radial annular flange 36 which bears against the adjacent wing I8. The corners occurring between the anges 36 and the bodies of the bushings 33 are spherically concaved to constitute ball races 31. The outer bushings 35 are provided with annular radial iianges 38 which bear against the inner sides of the wings I9. The corners occurring between the flanges 38 and the bodies of the bushings 34 are spherically concaved to constitute ball races 39. It will be observed that the bodies of the outer bushings 34 are somewhat, larger in diameter than the bodies of the inner bushings 33 so that the races 39 are somewhat larger in circumference than the races 31. Lugs 4D may be provided on the bushings 34 or their flanges 38 to cooperate with the lower ends of the wings I9 to prevent rotation of the bushings and to assist in transmitting operating thrusts from the bushings to the wings. The anges 36 and 38 bearing on the opposing surfaces of the wings I8 and I9 are received or partially received in the opposite ends of the cutter openings 28 and may serve to close the ends of the openings.

The means for rotatably supporting the cutters 26 include annular ribs 4I on the walls of the cutter openings 28. The ribs 4I are spaced between the ends of the cutters 26. The inner sides of the ribs 4I are spherically concave and constitute ball races 42 which oppose the above described races 31. The outer sides of the ribs 4I are spherically concave to constitute ball races 43 which oppose the above described races 39. It is to be noted that center lines extending through the centers of the

Opposing races

31 and 42 and center lines extending through the

opposing races

39 and 43 are pitched relative to the longitudinal axes of the pins 29, the lines extending. through the

races

31 and 42 being pitched in one direction and the lines extending through the

races

39 and 43 being pitched in the other direction.

In accordance with the invention series of balls 44 surround the bushings 33 to cooperate with the

races

31 and ,42 and series of balls 45A surround the bushings 34 to cooperate with the

races

39 and 43. The balls 45 are considerably larger than the balls 44 to assume the principal vertical operating thrusts as well as the outwardly directed end thrusts applied to the cutters 26.

The series of balls 44 and 45 rotatably support the cutters 26 on the

bushings

33 and 34 to assume all of the radial thrusts from the cutters. The above described relationship between the

races

31 and 42 is such that the balls 44 transmit the inward end thrusts from the cutters 26 and assist in transmitting the radial thrusts from the cutters. The

races

39 and 43 are related so that the balls 45 transmit the outward end thrusts from the cutters 26 and assist in transmitting the radial thrusts from the cutters. The cutters 26 are entirely rotatably supported by the series of balls 44 and 45 and their ends do not bear on the wings I8 and I9 of the body III. The cutters 26 rotatably mounted, as just described vrotated about downwardly and inwardly inclined axes and project downwardly and outwardly beyond the lower ends of the Wings yI8 and I9 to act on the outer portion of the well bore and cut the bore to gauge.

The inner cutting means constitutes the assembly of the pin I2, the cutters I3 and I4 and the bearing means I5 which assembly may be attached to the body I and removed from the body as a single unit. The inner cutting means is arranged between the diametrically opposite legs 2| at the lower end of the body I0. The pin I2 is the supporting element of the inner cutting assembly. The pin I2 is an elongate integral part whose end portions or principal portions are inclined downwardly and outwardly from an intermediate portion 46. The intermediate portion 46 of the pin I2 is thickened or enlarged and has at sides and a flat substantially horizontal upper surface 41. The lower end of the body web I1 is provided with an opening or notch 48 shaped to receive the enlarged portion 46 of the pin I2. The upper surface 41 of the pin enlargement 46 is adapted to bear upwardly against the wall of the notch 48 for the transmission of the vertical thrusts from the pin I2 to the body I9. The opposite ends 49 of the enlarged pin portion 46 are downwardly convergent and constitute substantially normal shoulders at the inner ends of the principal cutter carrying portions of the pin I2.

The invention provides novel eiective means for removably securing the enlarged intermediate portion 46 of the pin I2 to the body I8. A cap screw 50 is passed downwardly through a vertical opening in the web I1 and its lower portion is threaded into a socket 52 in the thickened portion 46 of the pin I2. The head of the cap screw is received in the upper portion of the opening 5I and a rubber washer 52a is provided under the head of the screw to prevent the leakage of the circulation iluid about the screw. Means is provided for preventing unthreading of the cap screw 59. A plate 54 is welded to the lower Wall of the chamber 23 to extend across the upper end of the opening 5I. A polygonal pin 55 is force-fitted in a correspondingly shaped opening inV the plate 54 to extend into the polygonal socket in the end of the cap screw 59. The pin 55 fitting the socket in the cap screw 50 positively prevents unthreading of the screw. The plate 54 andthe pin 55 are accessible through the passage 22.

The cutter supporting pin I2 projects radially outward in both directions from adjacent the center of the bit to have its opposite ends adjacent the inner sides of the legs 2 I. The ends of the pin I2 are preferably spaced from the inner sides of the legs 2|. Screws 56 are passed inwardly through openings 51 in the legs 2| and have their inner portions threaded in sockets 58 flo in the ends of the pin I2. The screws 56 secure the ends of the pin I2 to the legs 2| of the body I6. The heads 'of the screws 56 are countersunk in the openings 51. The heads of the screws 56 may have parts peened into notches 58* in the outer sidesof t"e legs 2| to prevent loss or unthreading of the screws. In accordance with the invention the pin I2 is graduated to have annular outwardly facing shoulders 59 spaced between the enlarged portion 46 and the outer ends of the pin. e

The inner cutters I3 and I4 are provided to act on the inner portion of the Well bore and' are arranged in pairs, there being one cutter I3 and one cutter |4 on each principal portion of the pin I2. The innermost cutters I3 are cylindrical roller cutters provided with peripheral cutting teeth 60. The opposite ends of the cutters I3 may be plain and flat. The teeth 68 preferably overhang or project inwardly beyondthe inner ends of the cutters |3 to act on the earth formation immediately adjacent the center of the well bore as will be hereinafter described. An annular rib 6| is provided on the interior of each cutter I3. The inner and outer sides of the ribs 6| are spherically concavedto constitute ball races 62 and 63, respectively. y

The cutters I4 are frusta-conical roller cutters arranged around the outer portions of the pin I2 with their small ends facing inwardly. The cutters I4 are somewhat larger in diameter than the innermost 'citters I3. The opposite [ends of the cutters I4 may be plain and fiat. Suitable peripheralcutting teeth 64 are provided on the cutters I4. e cutters I4 are tubular having central longitudinal openings 65. An annular flange or rib 66 is provided on the wall of each cutterwpening 65. The ribs 66 are spaced a short distance from the inner ends of the cutters I4. The inner and outer sides of the ribs 66 are spherically concave to constitute ball races 61 and 68, respectively. A third spherically concaved ball race 69 is provided on the interior of each cutter I4. The races 69 are adjacent the outer ends of the cutters I4 and face outwardly, as ilare provided with radial flanges 12 which bear against the inner sides of the legs 2 I. 'I'he flanges 12 are partially received in the outer ends of the openings 65 in the cutters |4. YW'elds 13 rigidly connect rthe lower portions'of the anges 12 with the lower ends of the legs 2|. The welds 13 rigidly secure the bushings 1|) to the legs 2| to prevent chattering lof the bushings and the end rportions of the pin I2. The corners occurring between the yflanges 12 and the bodies of the bushings 1II are spherically concaved to constitute ball races 14. 'I'he races 'I4 oppose the races 69 on the interiors of the cutters I4.

The bearing means I further lincludes annular series of balls 15 surrounding'the bushings 16 to cooperate with the races 69 and: the races 14. The

races

69 and 14 are related :so that a line drawn through the points of contact of a ball 15 with the races is pitched relative to the longitudinal axis of the pin I2 in such a manner that the balls 15 assume outward end thrusts on the cutters I4, as well as radial thrusts on the cutters. 'I'he bearing means I5 include annular series of balls 16 cooperating with the races 68 on the interiors of the cutters I4 and directly bearing on the pin I2. The inner ends of the bushings may contact or engage the balls 16 to hold them in position. 'Ihe balls 16 may assume some of the radial thrusts on the cutters I4 and following wear -of the

races

69 and 14 may assume some of the outward end thrusts on the cutters I4. It will be. observed that the balls assisted by the balls 16 assume the outward end thrusts on the cutters I4 as well as the radial thrusts on the cutters. This is important as it eliminates the necessity for thrust washers or the like at the outer ends of the cutters I4 and prevents wearing of the outer ends of the cutters and the body legs 2|.

The bearing means I6 further include sleeves or rings 11 closelyiitted on the pin I2 to bear inwardly against its shoulders 59. The rings 11 occur in the planes between the adjacent cutters I3 and I4. The outer corners of the rings 11vare provided with relatively small ball races 18 which oppose the races 61 on the interiors of the cutters I4. Series of balls 19 are provided to cooperate with the races 61, the races 18 and the surfaces of the pin I2. The races 61 are related to the races 18 and the-.points of contact of the balls 19 with the pin I2 so that the balls assume or transmit the inward end thrusts imposed on the cutters I4, as well as radial thrusts on the cutters. From the above it will be seen that the series of

balls

15 and 19 assisted by the balls 16 rotatably support the cutters I4 and assume or transmit al1 of the radial thrusts on the cutters as well as the inner and outer end thrusts on the cutters. The cutters I4 being supported by the

balls

15, 16 and 19 are free to rotate with a minimum of friction and are dependably retained in the proper operative positions. '4

The improved bearing means I5 of the invention further includes spherically concaved ball races 85| occurring in the corners between the surfaces or ends 49 of the pin portion 46 and the adjacent peripheral surfaces of the major body parts of the pin I2. The races 80 oppose the races 62 on the interiors of the inner cutters I3. Annular series of balls 8| surround the pin I2 to cooperate with the races 62 and 80 to rotatably support the inner end portions of the cutters |3. a line drawn through the points of contact of a ball 8| with a pair of opposing races 62 and 80 is pitched relative to the pin I2 in such a manner that the series of balls 8| assume or transmit inward end thrusts on the cutters t3, as well as radial thrusts on the cutters. 'I'he cutter-supporting means I5 further include series of balls 83 cooperating with the races 63 and the portions of the pin I2 of large diameter. The balls 83 also engage against. spherically concaved races 84 on the inner ends of the rings 11. 'Ihe relationship between the races 88 with the points of The races 62 and 80 are related so that contact of thebal1s 83 with the pin I2 and with the races 84 is such that the balls 83 assume the outward end thrusts on the cutters I3 as well as the radial thrusts on the cutters. The innermost inner cutters I3 are rotatably supported by the spaced series of balls 8| and 83 for rotation with a minimum 4amount of friction. As described above, the series of balls 8| and 83. respectively,

assume the inward end thrusts and the outward end thrusts imposed on the cutters I3 so that end thrust washers for the cutters are unnecessary. The cutters I3 are rotatably supported on the pin I2 through the balls 8l and 83 so that the 5 inwardly projectingparts of their teeth 60 act on the formation at the bottom of the bore immediately adjacent its center.

In operation the bit is connected with thelowe end of a rotary well drilling string and operated in the well in accordance with the rotary method of well drilling. During operation the outer cutters II act on the outer portion of the well bore in an annular path to out the bore to gauge and to assist in cutting away the formation at the bottom of the bore. The inner cutters ,I3 and I4 follow concentric annular paths in their action on lthe formation to cut away the formation atA the bottom of the bore. The several cutters are supported for free independent rotation about their own axes. The outer cutters II are rotatably supported by the series of balls 44 and 45 ln such a manner that the radial thrusts andl the i end thrusts on the cu'tters are transmitted through the balls. The cutters II are supported between balls 44 and 45 so that their ends do not bear against the body wings I8 or I9 or the

bushings

33 or 34 and the ends of the cutters are not subjected to wear. The annular series of balls 44 and 45 are long wearing and dependable to vrotatably support the cutters Il to cut the bore to gauge for 'a long period of operation. 'Ihebushings 33-and 34 are tted between the body .wings I8 and I9,so that' they do not have end movement or play and are held against rotation 35 by their

respective lugs

35 and 40. Following extended use of the bit the

bushings

33 and 34 and the series of balls 44 and 45 may be replaced.

As described in full above the inner cutters I3 and I4 are entirely supported by the series of

balls

8l and 83 and 15, 'I6 and 19, which series of balls assume all radial thrusts as well as all of the end thrusts transmittedthrough the cutters.` 'Ihe balls are longwearing and rotatably support the cutters I3 and I4 for free Arotation 45 in their proper positions for a long period of operation. The adjacentvcutters I3 and I4 do not bear one against the other and it is unnecessary to provide thrustwashers between the adjacent cutters. It is -also unnecessary to provide thrust washers or thrust bearings at the inner ends of the cutters I3 or the outer ends of the cutters I4. The assembly of the severalinner cutters I3 and I4 the pin I2 and the bearing means I5 is easily and quicklyl mounted'- on the lower end of the body I0. The pin I2 is securely and rigidly connected with the body I0 intermediate its ends by the screw 50. 'I'he intermediate portion 46 of the pin bears against the Wall of -the recess or notch 48 for the transmission of 80 vertical forces. The opposite ends of the cutter carrying pin I2 are dependably secured tothe legs I2 by the screws'56. The bit is inexpensive to manufacture and is easy' to service and recont, .dition for operation. s

Having described only 'a typical preferred form and application of my invention I do not Wish to be limited or vrestricted to the specicdetails herein s'et forth, but wish to reserve to myself any variations or modifications ,that may appear to those skilled in the art or fall within the scope of the following claims.

IHaving described my invention, I.claim:

1. A well'bit including, a body,i 'outer cutting means on the lower end of the body for cutting v the well bore to gauge., a supporting pin on the lower end of .the body, a roller cutter for acting on the formation at the inner portion of the bore, spaced ball races formed directly on the interior of said'cutter and facing inwardly and toward the adjacent ends of the cutter, and a 5 series of balls cooperating with each race and rotatably supporting the cutter on the said pin.

2. In a well bit, a body, a supportingI member carried by the body, a cutter having two spaced internal races, one race facing inwardly and to- 10 ward one end of the cutter, the other race facing inwardly and toward the other end -of the cutter, a ball race on the member substantially opposing the iirst mentioned race, balls cooperating with the first mentioned race and the race 15 on-the member, a washer on the member having aball race substantially opposing said other race. and a series of balls cooperating with said other race and the race on the washer.

3. In a well bit, a body, a supporting member 2o on the body having two shoulders facing in the same direction, a ball race on one shoulder, a roller cutter around the member having a race opposing the first named race, a series of balls cooperating in the said races, a ring held against 25 the other shoulder, a second race on the interior of the cutter, and a series of balls cooperating with said second race and the member and held in. place by said ring. v

4. In a well bit, a body, a supporting member 30 on the body having two shoulders facing in the same direction', a ball race' on one shoulder, a

roller cutter around the member having a race opposing the rst named race, a series of balls cooperating in the' said races, a second race on 35 the interior of the cutter, a series of balls cooperating with said second race and the member, a ring on the member held against the other shoulder, and a race on the ring cooperating with the second mentionedf series of balls. 40

5. In a well bit, a body, a supporting pin on the body having a radial shoulder, adjacent cutters surrounding the pin.l races in the cutters facing inwardly and toward the adjacent ends of the cutters, a ring on the pin bearing against 5 said shoulder, and series of balls cooperating with said races and the pin and engaging against the ring for the transmission of end'thrusts from the cutters.

6. In a well blt, a body, a supporting pin on 5, the body having a radial shoulder, a ring on the pin bearing against said shoulder, abushing on the pin, a cutter surrounding the pin, a race on the interior of the cutter facing inwardly and axially toward the ring,.a series of balls coop- 5| erating with said race, the pin and the ring for the transmission of radial thrusts and end thrusts in one direction, a race on the bushing,

' a second race on the interior of the cutter opposing the race on the bushing, and a series oi.' ballsI cooperating with said second race and the lrace on the bushing for the transmission of radial thrusts and end thrusts in the other direction.

7. In a"we1l bit, a body, spaced legs on the lower end of the body, a web between the legs, a u separately formed cutter supporting pin, means securing the ends of the pin to the legs, a part yon the pin having bearing engagement against to the legs, a part on the pin'tting said notch and means securing said part to the web.

9. In a, well bit, a. body,spaced legs on the lower end of the body, a web between the legs, the web having a. at Walled notch, a cutter carrying pin, means securing the ends of the pin to the legs, a. part on the pin tting said notch and means securing said part to the webI scid means including a screw threaded into the said part, a member welded on the web, and a.

to prevent unthreading of the screw.v

ALFRED C. CATLAND.