US2061650A

US2061650A - Roller bit

Info

Publication number: US2061650A
Application number: US701142A
Authority: US
Inventors: Alfred C Catland
Original assignee: Globe Oil Tools Co
Current assignee: Globe Oil Tools Co
Priority date: 1933-12-06
Filing date: 1933-12-06
Publication date: 1936-11-24
Anticipated expiration: 1953-11-24

Description

NOV. 24, 1936. c D 2,061,650

Filed Dec. 6, 1955 Away ,9 v

Patented Nov. 24, 1936 UNITED STATES PATENT OFFICE 7 ROLLER BIT Application December 6, 1933, Serial No. 701,142

18 Claims.

This invention relates to a well drilling tool and relates more particularly to a well drilling bit. A general object of this invention is to provide a simple, practical and particularly efllcient roller bit for use in the rotary method of well drilling.

Another object of the invention is to-provide a well'drilling bit that is very rapid and effective in its cutting action or formation penetrating action.

Another object of the invention is to provide a well bit embodying an improved form of roller cutter.

Another object of the invention is to provide a well bit embodying a simplified and effective means for dependably mounting a plurality of roller cutters.

Another object of the invention is to provide.

a well bit including a plurality of roller cutters formed and positioned with respect to one another to have zones or paths of active engagement with the earth formation that occupy or cover the entire surface at the bottom of the well bore whereby the bit is smooth running and rapid andefiicient in operation.

Another object of the invention is to provide a novel roller cutter having an annular series of spaced cutting teeth whose length materially less than the length of the cutter, the said series being disposed so that its teeth have cutting engagement with the earth formation from one side to the other of the path of travel of the cutter during each complete revolution of the cutter.

The teeth or the improved cutter provided by the invention are short with respect to the length of the cutter so that the driling pressure or active feed pressure imposed on the teeth is materially increased per lineal unit of cutting edge making the cutter very rapid and efficient and the teeth are in a continuous annular series that is inclined or oblique with respect to the axis of rotation of the cutter and extends from one end of the cutter to the other whereby the teeth have active engagement with the earth formation throughout the width of the path of travel of the cutter. Roller cutters must of necessity be of considerable length to have bearings that are sufficiently long to be long wearing and where the individual teeth of a cutter extend throughout its entire length, as is the usual practice, there is an appreciable difference in the distance and speed of travel of the inner and outer portions of the teeth which results in an undesirable dragging and scraping action. The individual teeth of the cutter provided by this invention are short with reference to the length of the cutter so that they do not have the undesirable scraping action of the long teeth of the typical roller cutters.

Another object of the invention is to provide a roller cutter of the character mentioned above that operates without wobbling and without imparting an irregular motion to the bit.

Another object of the invention is to provide a roller cutter of the character mentioned that may be easily and inexpensively manufactured from cylindrical stock.

It is a further object of the invention to provide a roller bit of the character mentioned that is simple and inexpensive of manufacture.

Other objects and features of the invention may become apparent from the following detailed description of typical preferred forms and applications of the invention, throughout which description reference may be had to the accompanying drawing in which: I

Fig. l. is a longitudinal detailed sectional view of the bit provided by the invention. Fig. 2 is a bottom elevation view of the bit. Fig. 3 is an enlarged side elevation of the two inner cutters apart from the bit showing them in the positions they occupy with respect to one another. Fig. 4 is an end view of one of the cutters illustrated in Fig. 3. Fig. 5 is a side view and end view of another form of cutter and Fig. 6 is a side elevation of still another form of cutter.

The well drilling bit provided by this invention includes generally a bit head body iii, two bearing members or cutter carrying members ii and it on the lower end of the body, outer roller cutters A and B on the members H and i2, respectively, and inner roller cutters C and D on the members H and I2, respectively.

The bit head body ill is adapted to be operated on the lower end of a string of drill pipe and is provided at its upper end with suitable means for facilitating connection with the string. The particular body Ill illustrated in the drawing has a shank portion l3 at its upper end provided with a central screw threaded socket It for the reception of the pin of the drill collar or another part of the drilling string. The lower portion or main portion l5 of the body i0 is widened in one directionbeing substantially rectangular in transverse cross section. Two sockets or recesses it are provided in the lower end of the body to hold or receive the cutters. The recesses i6 extend through the body portion i5 from one side to the other and leave two depending legs H at diametrically opposite extremities of the portion it. The inner sides I8 of the legs ii are preferably inclined downwardly and outwardly. A downill) wardly projecting partition wall l9 separates the two recesses IS. The partition wall I9 is substantially vertical and is positioned at one side of the central longitudinal axis of the bit. Fluid passages or ports 20 extend downwardly from the bottom of the socket H to the upper walls of the recesses l6. There may be two spaced ports 20 discharging downwardly into each recess [6 to provide for the effective flushing of the two outters mounted in each recess.

The bearing members or cutter carrying members and I2 each rotatably support an outer roller cutter and an inner roller cutter. The members H and 2 bridge or extend inwardly through the recesses |6 from the legs H to points below the end of the partition wall l9. Each cutter carrying member includes an outer portion 2| of comparatively large diameter to carry an outer roller cutter and an inner portion 22 of reduced diameter to support an inner roller cutter. The members II and I2 are positioned so that their outer portions 2| are inclined downwardly and inwardly. In the particular assembly illustrated in the drawing the two portions 2| have the same inclination. The inner portions 22 of the cutter I carrying members are stepped or offset downwardly so that outwardly facing shoulders 23 are provided at the inner ends of the portions 2|. The portions 2| of the cutter carrying members may seat in notches or recesses in the lower ends of the legs l and may be welded to the legs as at 24. The inner portion 22 of the member II has its longitudinal axis substantially normal to the central longitudinal axis of the bit while the inner portion 22 of the member l2 has a longitudinal axis inclined downwardly and inwardly toward the central axis of the tool. The inner portion 22 of the member |2 may have a smaller pitch or inclination than its outer portion 2|. As the inner portions 22 of the cutter carrying members are of reduced diameter inwardly facing shoulders 24 are provided on the members at the points of joinder of the portions 2| and 22. The inner ends of the portions 22 are received in sockets in a block 26. The block 26 bears upwardly against the lower end of the wall i9 and is held against movement by dowel pins 27. The side of the block 26 facing the recess l6 through which the member passes may be substantially vertical while the opposite side of the block is preferably inclined downwardly and outwardly to be substantially normal to the 1ongitudinal axis of the portion 22 of the member l2. A screw 28 passes through a longitudinal opening 29 in the inner portion 22 of the member 8 and is threaded into a socket in the inner portion 22 of the member I2. The head of the screw 28 may be counter sunk in the outer end of the opening 29. The screw 28 effectively ties together or connects the members II and I2 and maintains them in their proper assembled relation with the block 26. The manner of assembling the cutter carrying members II and I2 on the body ||l will be subsequently described.

The outer cutters A and B are provided to act on the side wall of the well bore and the peripheral portion of the bottom of the bore. The outer roller cutters A and B are rotatably mounted on the bearing portions 2| through bushings 30. Thrust washers 3| may be provided at the outer ends of the bushings 30 and keys 32 may hold the washers and bushings against rotation. The bushings 30 are provided with outwardly facing annular shoulders 33 for engagement by opposing complementary shoulders on the interiors of the cutters A and B whereby inward thrusts are effectively transmitted from the cutters to the bushings. The inner ends of the bushings 30 are adapted to bear against the shoulders 23 of the members I and 2.

The cutters A and B, illustrated in the drawing, are cylindrical in their general configuration and are provided with axial or longitudinally extending peripheral cutting teeth 34. Due to the locations of the cutters A and B and their downwardly and inwardly inclined axes of rotation, the teeth 34 project outwardly beyond the outer sides of the legs l5 to have reaming engagement with the side wall of the well bore. The outer corners of the teeth 34 are preferably beveled to be substantially vertical when the respective teeth are in active cutting engagement with the formation. The outer cutters A and B in being located at diametrically opposite sides of the bit, balance the bit during operation and their paths of travel or engagement with the formation, lap over one another. In practice the cutter B may be considerably shorter than the cutter A as illustrated in the drawing. It is to be noted that the bushing 30 on the member covers the outer end of the opening 29 and, therefore, effectively prevents displacement of the screw 28.

The inner cutters C and D are provided to act on the formation at the bottom of the well bore within the annular cut made by the outer cutters A and B. Bushings 36 are provided on the bearing portions 22 of the members II and I2 to rotatably carry the cutters C and D. The bushings 36 have outwardly projecting thrust flanges engaging the shoulders 25. Thrust washers may be provided between the inner ends of the bushings 36 and the block 26 and the bushings and washers may be held against rotation by keys 31. The cutters C and D may be alike in shape or design as illustrated in Figs. 1 and 3 of the drawing. Each cutter C and D includes a body 40 having a central longitudinal bore or opening 4| for passing a bushing 36. The ends 42 of the cutters are flat and normal to the longitudinal axes of the bodies 40.

It is a feature of the invention that each cutter C and D has a continuous circumferential series of spaced teeth which series lies in a plane that is oblique or inclined relative to the longitudinal axis of the cutter. The teeth 43 of the cutters C and D may be spiralled teeth or may be longitudinally extending teeth. In the particular form of the invention being described, the teeth 43 are longitudinal teeth extending parallel with the longitudinal axis of'the cutter. The particular teeth 43 illustrated in the drawing have fiat sides converging outwardly to longitudinally extending cutting edges 44. It is an important feature of the invention that the teeth 44 are materially shorter than the bodies 40 of the cutters, that is, the individual teeth 44 extend only a part or a fraction of the length of the cutter. In the particular cutters C and D illustrated in the drawing the teeth 43 are approximately one-half as long as the cutter bodies 40. The teeth 43 of each cutter are of equal length and are arranged in a continuous series that is pitched so that the teeth have active engagement with the earth formation from one edge to the other of the path 01' the cutter during each complete revolution of the cutter. The ends of the teeth 43 are flat and parallel and lie in two parallel planes L obliquely disposed or inclined relative to the axis of rotation of the cutter. The

planes L of the opposite ends of the series of teeth are disposed relative to the axis of rotation of the cutter so that each plane L intersects a continuation of the normal plane of an end of the cutter body at the outer corner X of a tooth 43. The series of teeth 43 arranged relative to the axis of the cutter as just described extendsaround the cutter body 40 in diagonal relation thereto so that the teeth act throughout the width of the path of travel of the cutter. Fig. 3 of the drawing clearly illustrates the pitched or inclined series of teeth 43 of the two cutters C and D. The broken lines of Fig. 3 illustrate the positions of the series of cutters 43 when the cutters have each been turned one-half of a revolution from the rotative positions illustrated by the full lines. The peripheries of the end portions 45 of the cutter bodies 40 may be slightly tapered inwardly toward the opposite ends of the cutters.

The cutters C and D as rotatably mounted on the inner portions 22 members II and I2 are positioned so that the teeth-43 of the cutter D make anannular out in the formation at the bottom of the bore which extends inwardly from the inner edge of the annular cut made by the outer cutter A. The cutter C is positioned so that its teeth 43 make an annular cut in the earth formation at the bottom of the bore which extends inwardly from the cut made by the cutter D to the center of the bore. From the above it will be seen that the cutters of the bit have paths of active or cutting action which entirely occupy or cover the bottom of the well bore. As the teeth 43 of the inner cutters C and D are comparatively short the downward feeding or drilling pressure is concentrated at their cutting edges 44, there being a heavy drilling pressure per lineal unit of the short cutting edges 44 in engagement with the earth formation. As the bit is rotated during drilling the several cutters rotate independently on their mountings and the teeth 43 of the cutters C and D in being arranged in inclined series successively come into cooperation with different portions of the path taken by the cutters. In this manner the teeth 43 act on the formation throughout the entire widths of the paths of activity of the cutters C and D during each revolution of the cutters. The arrangement of the cutters 43 in the inclined series provides for an endwise or longitudinal sliding movement of the teeth 43 during their engagement with the earth formation which has a desirable freeing action when drilling in certain earth for mations.

The cutters C and D may be made from cylindrical stock bored concentrically to its longitudi- 1 nal axis. In making a cutter, the teeth 43 are first cut in the cylindrical body and the stock or body is set at the required angle for the turnirg down of the end portions 45 to leave the diagonal or inclined series of projecting teeth 43. The base portions of the teeth turned down from the opposite end portions of the cutter may remain as ribs on the portions 45 as illustrated in Figs. 3 and 4 of the drawing. V

In assembling the bit, the bushings 36 and the inner cutters C and D are first assembled on the inner portions 22 of the members H. The inner ends of the cutter carrying members H and i2 are then fitted into the block 26 and the members are securely connected by the screw 28. The assemblies of the outer cutters A and B with their bushings, washers and keys are then arranged on the outer portions 2| of the members II and I2.

The assembly of the two members H and I2 carrying the cutters is then arranged on the lower end of the body 10 and the members II and H are welded to the legs H. The block 26 is secured to the wall H! by the dowels 21. The cutter mounting assembly of the present invention dependably and effectively supports the four outters for rotation and is such that none of the parts can become loosened or displaced.

It is believed that the operation of the bit will be readily apparent from the foregoing detailed description. When the bit is attached to the lower end of a drilling string and rotated in the bottom of a well bore in the usual manner the several cutters are independently rotated through their engagement with the earth formation. The outer cutters A and B are effective in cutting the outer or peripheral portion of the bottom of the bore and in reaming the side wall of the bore. The two cutters A and B positioned and operating as described above stabilize the drill and provide for its smooth operation. The inner cutter D operates to make an annular cut in the formation at the bottom of the bore that extends inwardly from the cut made by the cutter A. The cutter C makes an annular cut in the earth formation that extends outwardly from the center of the bore to the cut made by the cutter D. The teeth 43 of the cutter C and D are successively brought into engagement with the earth formation and as they are short and have very limited engagement with the formation, the drilling pressure or feeding pressure per lineal unit of cutting edge is great. This provides for the rapid and efiicient operation of the cutters. Further, the teeth 43 have little or no tendency to track or follow one another in their engagement with the earth formation and have a desirable endwise movement when contacting with the formation. The teeth 43 in being arranged in inclined series on the bodies of the cutters have active engagement with the earth formation throughout the entire widths of the paths covered by the cuttersr Fig. 5 of the drawing illustrates a cutter of a form that may be employed in the bit in place of the cutters C and D. The body 60 of the cutter illustrated in Fig. 5 of the drawing is provided with a central longitudinal bore 6i. An annular series of projecting teeth 62 is provided on the cutter body 60. The series of teeth 62 is inclined or oblique relative to the longitudinal axis of the cutter. The ends of the teeth 62 lie in parallel planes which are inclined relative to the axis of the cutter so that each plane intersects the plane of an end of the cutter body at the outer corner of a tooth 62. The teeth 62 taper longitudinally of the cutter and have cutting edges 63 which are inclined relative to the longitudinal axis of the cutter. The cutting edges 63 are inclined outwardly toward the opposite ends of the cutter. The cutting edges 63 in being inclined as just described have limited engagement with the earth formation and, therefore, are rapid and efficient in their cutting action. Theteeth 62 are preferably very much shorter than the cutter body 60.

Fig. 6 of the drawing illustrates a form of cutter that is similar, generally, to the cutter illustrated in Fig. 5. The cutter shown in Fig. 6 has a body 10 provided with a central longitudinal bore H. An annular series of comparatively short teeth [3 projects from the body 70. The series of teeth 13 is oblique or inclined relative to the rotative axis of the cutter and its opposite ends lie in parallel planes. The cutting edges 14 of the teeth I3 are pitched or inclined relative to the axis of the rotation of the cutter being pitched in the opposite direction to the cutting edges 63 of the form of cutter illustrated in Fig. 5. The inner points of the teeth l3 are the highest or outermost points of the teeth and thus have active cutting engagement with the earth formation. Due to the inclined relationship of the cutting edges H with the axis of rotation of the cutter, the teeth have more limited engagement with the formation than the teeth of the cutters C and D described above.

In the cutter shown in Fig. 5 and the cutter shown in Fig. 6 the curve generated by the highest points or outermost points of the series of cutting teeth is an ellipse so that the engagement of the teeth with the earth formation results in a lifting and falling motion of the cutter, the extent of this movement being dependent upon the pitch or inclination of the cutting edges of the teeth relative to the axis of rotation of the cutter. It is believed that it will be apparent how the forms of cutters, illustrated in Figs. 5 and 6 of the drawing may be employed in the bit in place of the cutters C and D, it being understood that the improved. cutters of the present invention are not to be construed as limited for use on the particular bit illustrated in Figs. 1 and 2 of the drawing and described above.

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

Having described my invention, I claim:

1. A well bit including a body having two recesses in its lower end, inclined members rigidly attached to the body and extending across the recesses, cutters in the recesses rotatable on the members, and means connecting the inner ends of the members, said means including a screw extending through an opening in one member and threaded into the other member.

2. A well bit including a body having two recesses in its lower end, a member extending inwardly across each recess, each member having a downwardly and inwardly inclined outer bearing portion and an inner bearing portion of reduced diameter, means supporting the inner ends of the members against upward thrusts, roller cutters rotatable on the outer bearing portions for making an outer annular cut and for engaging the side wall of the well bore, and roller cutters rotatable on the inner bearingportions for making annular cuts one within the other which extend from the center of the bore to the first mentioned cut.

3. A well bit including a. body having two recesses in its lower end, a member extending inwardly across each recess, each member having a downwardly and inwardly inclined outer bearing portion and an inner bearing portion of reduced diameter, roller cutters rotatable on the outer bearing portions for making an outer annular cut and for engaging the side wall of the well bore, and roller cutters rotatable on the inner bearing portions for making annular cuts one within the other which extend from the center of the bore to the first mentioned cut, one of said inner bearing portions being substantially normal to the axis of rotation of the bit and the other inner bearing portion being inclined downwardly and inwardly.

4. A well bit including a body having two recesses in its lower end, a wall depending from the body and separating the recesses, members attached to the body and extending inwardly across the recesses, each member having an outer bearing portion and a reduced inner bearing portion, roller cutters rotatable on the outer hearing portions, cutters rotatable on the inner bearing portions, a block bearing upwardly against the lower end of the wall and having sockets receiving the inner ends of the members, and a connecting screw tying together the inner portions of the members.

5. A well bit including a body having two recesses in its lower end, a wall depending from the body and separating the recesses, members attached to the body and extending inwardly across the recesses, each member having an outer bearing portion and a reduced inner bearing portion, bushings on said portions, roller cutters rotatable on the bushings, a block bearing upwardly against the lower end of the wall and having sockets receiving the inner ends of the members, the outer bearing portion of one member beieng inclined downwardly and inwardly and the inner bearing portion of said member being substantially horizontal and having a longitudinal opening, and a screw passing through said longitudinal opening and threaded into the other member, the bushing on the inclined outer bearing portion covering the end of said opening.

6. A well drilling bit including a body, outer cutting means on the lower end of the body for making an annular cut in the earth formation, and inner cutting means on the lower end of the body for cutting the formation within said an-- nular cut, the inner cutting means including a rotatable roller cutter body, and an annular series of circumferentially spaced projecting teeth extending around the cutter body, the teeth being materially shorter than the cutter body and the said series of teeth lying in a plane inclined relative to the axis of rotation of the cutter body.

7. In a well drilling tool, a cutter comprising a body rotatable about a longitudinal axis, and cutting teeth projecting from the body, the cutting teeth being materially shorter than the body and being in an annular series within a zone which extends diagonally around the cutter.

8. A well bit including a body having two recesses in its lower end, a member extending inwardly across each recess, each member having a downwardly and inwardly inclined outer bearing portion and an inner bearing portion of reduced diameter, roller cutters rotatable on the outer bearing portions for making an outer annular cut and for engaging the side wall of the well bore, and roller cutters rotatable on the inner bearing portions for making annular cuts one within the other which extend from the center of the bore to the first mentioned cut, each of the last mentioned cutters having an annular series of circumferentially spaced teeth surrounding it, said teeth being shorter than the cutter and lying within a zone or plane inclined relative to the axis of rotation of the cutter.

9. A well drilling bit including a body, outer cutting means on the lower end of the body for making an annular cut in the earth formation, and inner cutting means on the lower end of the body for cutting the formation within said annular cut, the inner cutting means including a rotatable roller cutter body, and an annular series of projecting longitudinally disposed teeth extending around the cutter body, the teeth being shorter than the cutter body and the said series of teeth lying in a zone inclined relative to the axis of rotation of the cutter body.

10. A well drilling bit including a body adapted to be attached to the end of, a rotatable drilling string, and cutting means on the lower end of the body including a cutter mounted on the body for rotation, and a plurality of spaced-projecting cutting teeth on the cutter, the teeth being materially shorter than the cutter and being in an annular series extending around the cutter and being within a zone or plane which is oblique relative to the axis of rotation of the cutter.

11. Awell drilling bit including a body adapted to be attached to the end of a rotatable drilling string, and cutting means on the lower end of the body including a cutter mounted on the body for rotation, and a series of spaced projecting cutting teeth on the cutter, the teeth being mate-- rially shorter than the cutter and lying within a zone whose opposite axial extremities are delined by substantially parallel planes inclined relative to the axis of rotation of the cutter, said planes intersecting the planes of the opposite ends of the cutter at points adjacent the outer corners of teeth of the series.

12. A tool of the character described including a body to be rotated, a spindle member on the body having a longitudinal axis inclined with respect to the axis of rotation of the body, and a cutter rotatable on the spindle member and having a plurality of spaced projecting teeth, the

teeth being shorter than the cutter and being in an inclined series within a zone which extends diagonally around the cutter.

13. A tool of the character described including a body to be rotated, a spindle on the body having a longitudinal axis angularly related to the axis 01. rotation of the body, and a cutter rotatable on the spindle and having an annular series of spaced cutting teeth extending around it, the teeth being shorter than the cutter and lying within a zone or plane inclined relative to the axis of rotation of the cutter.

' the axis of rotation of the cutter, the teeth in 14. A roller cutter for an earth boring tool including a body adapted for rotation, and an annular series of cutting teeth extending around the body, the teeth being shorter than the body and lying within a zone or plane inclined relative to 6 the axis of rotation of the cutter.

15. A roller cutter for an earth boring tool including a body adapted for rotation, and an annular series of cutting teeth extending around the body, the teeth being shorter than the body and 10 lying within a zone or plane inclined relative to the axis of rotation of the cutter, the teeth having cutting edges extending substantially parallel with said axis.

16. A roller cutter for an earth boring tool ineluding a body adapted for rotation, and an annular series of cutting teeth extending around the body, the teeth being shorter than the body and lying within a zone or plane inclined relative to eluding cutting edges inclined relative to said axis.

1'7. A roller cutter for an earth boring tool including a body adapted for rotation, and an annular series of cutting teeth extending around the body, the teeth being shorter than the body and lying within a plane obliquely disposed with respect to the longitudinal axis of the body, the teeth having cutting edges substantially normal to said plane.

18. A well boring tool including a body adapted to be rotated about a substantially vertical axis,

a cutter located at one side of said axis and carried by the body for rotation about an axis substantially transverse of said axis, and an annular series of projecting circumferentially spaced teeth on the cutter, the teeth being shorter than the cutter and the said series of teeth lying within 40 a zone which is oblique relative to the axis of rotation of the cutter.

ALFRED C. CA'I'LAND.