US2111751A - Well tool construction - Google Patents

Description

March 22, 1938. A. c. CATLAND WELL TOOL CONSTRUCTION Filed April 15, 1936 Patented Mar. 22, 1938 ,lllJSl WELL EOUL CGNS'ERIUCTHON Alfred C. Catland, Alhambra, Calif assignor to Globe Gil Tools Company, Los Nietos, Calif... a corporation of California Application April 13, 1936, Serial No. 74,165

4 Claims.

Thisinvention relates to well drilling tools and relates more particularly to well drilling tools embodying roller cutters. A general object of this invention is to provide an improved, efficient and very simple bearing means for the roller cutters of a well tool.

Another object of this invention is to provide a well tool construction embodying an easily manufactured roller cutter mounting that is efiicient and long wearing.

Another object of this invention is to provide bearing means for rotatably supporting the roller cutter of a well bit that efiects the proper transmission and the even distribution of the load or drilling forces on the cutter.

I Another object of this invention is to provide a well tool construction embodying roller cutters and bearing means for the cutters having thrust receiving faces normal or perpendicular to the direction of the forces transmitted through the cutters whereby there is a minimum end thrust on the cutters. Another object of the invention is to provide a well tool assembly of the character mentioned embodying plain bearings arranged on threaded pins and located to dependably receiveand transomit the forces resulting from the engagement of the cutters with the earth formation.

The various objects and features-of my invention will be fully understood from the following detailed description of a. typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. l is a side elevation of a well tool embodying the present invention, showing the principal portions of the tool in longitudinal cross section. Fig. 2 is an enlarged fragmentary longitudinal detailed sectional view illustrating the mounting of one of the inner cutters. Fig. 3 is a view similar to Fig. 2 illustrating the mounting of one of the outer cutters. Fig. 4 is a perspective view of the thrust washer embodied in the mounting of one of the inner cutters. Fig. 5 isa perspective view of the bearing of one of the inner cutter mountings. Fig. 6 is a perspective view of the bearing embodied in the mounting of an outer cutter and Fig. 7 is the thrust washer of an outer cutter mounting means.

The assembly or construction provided by the present invention is adapted to be embodied in well tools varying considerably in character. In the following detailed description the invention will be disclosed as embodied in the core drill illustrated in the drawing, it being understood that the invention is not to be construed as limited or restricted to the specific application disclosed.

The core drill illustrated in the drawing comprises an outer barrel Ill provided at its lower end with a sub i l. A tubular member I2 is fixed within the sub ii in spaced relation to its inner wall leaving an annular fluid passage it. A core catcher it is arranged in the tubular member if. The core catcher it illustrated is similar, generally,'to the core catcher fully described and claimed in'the co-pending application of John H. Howard, entitled Core recovering means, Serial No. 34,649, filed August 5, 1935, matured into Patent No. 2,063,437, granted December 8, 1936. An inner barrel it extends longitudinally through the outer barrel IE to receive the core. The inner barrel I5 is spaced from the interior of the outer barrel in leaving an annular fluid passage iii. The passages l6 and is are in communication and conduct or pass the circulation fluid downwardly to the bit head. A collar H is provided on the lower end of the inner barrel it. The collar H is rotatable between the upper end of the member l2 and a shoulder it to rotatably support the inner barrel l6.

The bit head or cutting head embodying the present invention comprises, generally, a head body 20 secured to the sub ii and having series of recesses A and B in its lower end, outer cutters X, inner cutters Y, means 2i rotatably supporting the outer cutters X in the recesses A and means 22 rotatably supporting the inner cutters Y in the recesses B.

The shoe or body 20 of the cutting head is tubular having a central longitudinal opening 23. The body 20 is secured to the sub it so that its opening 23 is aligned with the inner barrel l5. In the particular case illustrated in the drawing the body 20 is threaded on a pin 24 on the lower end of the sub ii. The lower end portion of the body 20 is thickened or provided with wings 25. The recesses A and B for carrying the cutters X and Y are provided in the lower end of the body 20. The recesses A are inclined having their inner and outer walls inclined downwardly and outwardly relative to the longitudinal axis of the tool. A slightly raised surface 26 is provided on the outer wall of each recess A. The inner walls 21 of the recesses A are fiat and parallel with the surfaces 26. Flat faces 28 are provided on the lower end of the body 20 at the lower ends of the surfaces 26 and the walls 21. The recesses B for carrying the inner cutters Y are inclined downwardly and inwardly having inclined walls. A raised surface 29 is provided on the inner wall of each recess B and is inclined downwardly and inwardly with respect to the longitudinal axis of the tool. The outer walls 30 of the recesses B are flat and parallel with the raised surfaces 29. Flat downwardly facing surfaces 3| are provided on the body 20 at the lower ends of the raised surfaces 29. Downwardly facing shoulders 32 occur on the wings 25 at the lower ends of the walls 30. The number and the spacing of the recesses A the recesses A and B. Ports II are provided in the sub ii to conduct the circulation fluid downwardly from the passage |3 to ports 10 in the body which discharge into the recesses A and B.

The outer cutters X are provided to act on the formation at the bottom of the well bore to cut the well bore to gauge. The cutters X are rotatably supported by the means 2| to project downwardly and outwardly from the lower ends of the recesses A. In accordance with the invention the outer cutters X are frusto-conical having their peripheries inclined or pitched. Axially extending cutting parts or teeth 33 are provided on the peripheries of the cutters X. Central longitudinal openings 34 extend through the outer cutters X. A central socket 35 enters each cutter X from its outer end. In accordance with the invention the sockets 35 are conical or frustoconical as illustrated in the drawing. The pitch of the walls of the sockets 35 is in the same direction as the peripheries of the cutters X and is substantially the same as the pitch of the teeth 33 and the peripheries of the cutters. The bottom or inner walls of the sockets 35 are fiat and normal to the longitudinal axes of the cutters. The opposite ends of the cutters X are fiat and normal.

The inner cutters Y are rotatably supported in the recesses B to cut and trim the core and to act on the formation at the bottom of the Well bore. The cutters Y are in the nature of cylindrical roller cutters. The inner cutters Y have fiat normal ends and axial peripheral cutting parts or teeth 36. Central longitudinal openings 31 are provided in the cutters Y. Central sockets 38 of substantial depth are provided in the inner ends of the cutters Y. The sockets 38 are cylindrical having cylindrically curved walls concentric with the longitudinal .axes of the cutters. The bottom walls or inner end walls of the sockets 38 are flat and normal to the axes of the cutters. The extreme outer end portions of the sockets 38 are flared or enlarged at 39.

The means 2| rotatably support the cutters X in the recesses A for rotation about downwardly and inwardly inclined axes. Each cutter mounting means 2| includes a screw or pin 40 extending through a recess A. The cutter supporting pins 4|] are arranged outwardly through openings 4| in the inner wall portions of the body 20 and their outer parts are threaded in openings 42 in the wings 25. The openings 4| and 42 are inclined downwardly and inwardly and carry the pins 40 so that their longitudinal axes are substantially normal to the surfaces 26 and the walls 21. Suitable heads 43 are provided on the inner ends of the pins 40. The heads 43 and the outer ends of the pins 40 may be ground away or bevelled to be flush with the adjacent body surfaces. The pins 40 pass freely through the openings 34 in the cutters X. Each pin 40 is provided between its ends with an outwardly facing annular shoulder 44. The shoulders 44 and the inner end walls of the sockets 35 are in or adjacent a common plane.

The means 2| rotatably supporting the cutters X include bearings 45 on the pins 40 cooperating with the sockets 35. The bearings 45 are frustoconical having fiat normal ends and pitched or inclined peripheries 45. The inner ends and the peripheries of the bearings 45 are hard faced being provided with layers 41 of hard wear resisting material. The walls of the sockets 35 and the peripheries 45 of the bearings 45 have their lower parts parallel with the face of the earth formation engaged by the cutting teeth 33 and are, therefore, substantially perpendicular to the direction of the forces on the cutters X resulting from the action of the cutters on the formation. This disposition of the bearings 45 and the sockets 35 reduces the end thrusts on the cutters X to a minimum. The inner ends of the bearings 45 are engaged by the shoulders 44 on the pins 40 whereby the bearings are held or clamped between the shoulders 44 and the raised surfaces 25. The outer ends of the bearings 45 have extensive engagement with the raised surfaces 26. The invention provides means for holding the bearings 45 against rotation. Integral lugs 48 are provided on the bearings 45 to cooperate with the faces 28 on the wings 25. The cutter mounting means 2| may include replaceable thrust washers 49 arranged on the pins 40 between the inner ends of the cutters X and the walls 21 of the recesses A. Integral lugs 50 on the thrust washers 49 cooperate with faces 28 on the body 20 to hold the washers against turning.

The means 22 support the cutters Y in the recesses B to rotate about downwardly and outwardly inclined axes. The means 22 includes pins 5i extending through the recesses B. The pins 5| are passed inwardly through openings 52 in the wings 25 and have their inner end portions threaded in openings 53 in the inner part of the body wall. The heads 54 of the pins 5| are suitably countersunk in the outer sides of the wings 25. The pins 5| are shouldered between their ends each having an inwardly facing annular shoulder 53.

The cutter mounting means 22 includes bearings 55 on the pins 5| rotatably carrying the cutters Y. The bearings 55 are cylindrical and have fiat normal ends. The inner ends of the bearings 55 cooperate with the raised surfaces 29. The outer ends of the bearings 55 are engaged by the shoulders 53. The bearings 55 are held or clamped between the shoulders 53 and the surfaces 29. The peripheries and the outer ends of the bearings 55 are faced with layers 56 of hard wear resisting material. The peripheries of the bearings 55 cooperate with the walls of the sockets 35 to rotatably support the cutters Y so that the walls of their openings 31 have suitable clearance with the pins 5|. The peripheries of the bearings 55 and the walls of the sockets 38 are concentric with the series of teeth 35 whereby they are perpendicular to the direction of the forces on the cutters Y resulting from its engagement with the formation. This relationship of parts reduces the end thrusts on the cutters Y to a minimum. The cutters Y are rotatably supported by the bearings 55 so that they are free of contact with the body. The cut away or flared parts 39 of the cutter sockets 38 have suitable clearance with the raised parts of the recess walls 29. The outer ends of the bearings 55 cooperate with the bottom walls of the sockets 38 to receive the principal end thrusts from the cutters Y. Integral lugs 51 are provided on the bearings 55 and cooperate with the surfaces 3| to hold the bearings against rotation. The cutter mounting means 22 includes replaceable thrust washers 60 arranged on the pins 5| between the outer ends of the cutters Y and the outer walls 30 of the recesses B. Means are provided for holding the washers 80 against rotation. Integral lugs 6| are provided on the washers Cl and cooperate with the shoulders 32 to hold the, washers against turning. The cutters Y rotatably mounted by the means 22 project from the lower ends of the recesses B and their cutting parts or teeth 36 are inclined downwardly and outwardly as they come into engagement with the earth formation. The

active parts of the cutters Y project inwardly at the lower end of the opening 23 to trim the core for reception in the opening a.

In operation the outer barrel I is connected with the lower end of a drilling string and the tool is rotated and fed downwardly in the well. The cutters x and Y make an annular cut in the earth formation and leave a core which is received in the opening 23 and the inner barrel IS. The ports III in the body 20 carry the circulation fluid downwardly from the ports H. to the recesses A and B to flush the cutters. The cutters x are dependably supported on the bearings 45 for free rotation about downwardly and inwardly inclined axes. The frusto-conlcal cutters X are mounted so that their teeth 36 are substantially horizontal as they come into engagement with the earth formation. The lower-most parts of the bearings 45 and the lower-most wall surfaces of the sockets 35 are also substantially horizontal. Thus the forces resulting from the engagement of the cutters x with the formation are substantially vertical and normal to the cooperating peripheries of the bearings 45 and the walls of the sockets IS. The thrusts or forces are transmitted through the bearings ll evenly and with minimum end thrust on the cutters. In actual practice it has been found that the principal or heavier forces on the outer cutters are closer to the outer ends of the cutters and the bearings 48 are positioned where they fully receive and transmit these forces. The bearings I! being hard faced are long wearing and as the operating thrusts and forces are evenly distributed the assembly is particularly long wearing.

The cutting parts 38 of the cutters Y are inclined downwardly and outwardly as they come into engagement with the earth formation and the thrusts or forces resulting from this action act along lines inclined downwardly and inwardly. The walls of the sockets 38 and the periphcries of the bearings 55 are concentric with the peripheral cutting teeth 36 so that the force transmitted through the cutters Y act along lines substantially normal to the axes of curvature of the peripheries of the bearings III and the walls of the sockets 38. Because of this relationship between the parts there is a minimum end thrust on the cutters Y and the operating forces and thrusts are evenly distributed. The end thrusts are directly taken by the bearings II which in tin-n directly bear on the body surfaces 29. The cutter mounting means II and 22 of the present invention are very simple and inexpensive. and are eflective and dependable. The cutter moimting means are long wearing and the cutters and the other parts may be easily and quickly replaced.

Having described only a typical preferred form and application of my invention I do not wish to be limited or restricted to the specific details 70 hercinsetfortnbutwishtoreservetomyseli'sny thrusts to the said ends variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. In a well bit, a body, a pin carried by the body and inclined downwardly and inwardly relative to the vertical axis of the body, a conical bearing on the pin having its base at the higher portion of the pin and having a flat normal inner end, and a tapered roller cutter having a tapered socket entering its outer end and having a length greater than one-half the length of the cutter and having a flat inner end wall, the socket rotatably receiving the bearing to receive the principal cutter thrusts, the end wall of the socket having end thrust engagement with the inner end of the bearing.

2. In a well bit, a body, a pin carried by the body and inclined downwardly and inwardly relative to the vertical axis of the body, a conical bearing on the pin having its base at the higher portion of the pin, and a conical roller cutter having a conical socket in its base portion rotatably receiving the bearing whereby the cutter is rotatable on the bearing, the surface of the conical bearing and the wall of the conical socket being substantially parallel with the active outer surface of the conical the socket having a length at least one half as great as the length of the cutter whereby the bearing receives the principal thrusts.

3. A core bit comprising, a body having spaced recesses at its lower end, downwardly and inwardly inclined pins extending through certain of the recesses, downwardly and outwardly inclined pins extending through the other recesses, tapered on the first mentioned pins having their at the higher portions of the pins, and having fiat normal inner ends, tapered outer roller cutters having tapered sockets in their outer ends rotatably receiving the bearings and having flat inner end walls transmitting end of the bearings, the tapered sockets and bearings having a length greaterthan one half the length of the cutters whereby the conical surfaces of the bearings receive the principal end thrusts, cylindrical bearings on the downwardly and outwardly inclined .pins, and cylindrical inner roller cutters rotatable on the last named bearings.

4. A core bit comprising, a body having spaced recesses at its lower end, downwardly and inwardly inclined pins extending through certain of the recesses, downwardly and outwardly inclined pins extending through the other recesses, tapered bearings on the first mentioned pins having their bases at the higher portions of the pins, fmsto-conical outer cutters rotatably supported on the tapered bearings, the active outer surfaces of the cutters being substantially parallel with the surfaces of the conical bearings, cylindriq cal bearings on the inner portions of the downwardly and outwardly inclined pins, and cylindrical inner roller cutters having sockets in their inner ends rotatably receiving the cylindrical bearings, the sockets and bearings having lengths greater than one half the lengths of their re spective cutters whereby the bearings receive the cutter, the bearing and-

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