US2201569A - Compact roller drilling bit - Google Patents

Description

May 21, 1940. J. A. zUBLlN COMPACT ROLLER DRILLING BIT Filed Feb. 21, 1958 elo/m A. Za//n A Trae/vs Y Patented May 21, A1940 UNITED STATES PATENT QFFICE 2,201,569 coMPAc'r ROLLER nmLLmG Brr John A. Zublin, Los Angeles, Calif. Application February 21, 1938, Serial No. 191,622

' 11 claims. (ci. zas-'11) 'I'he present invention is concerned with drilling tools for oil wells, and more specically to those tools having rolling cutters; and still more particularly to drilling bits of the type described in my United States Letters Patent Nos. 2,050,988, 2,050,989, 2,069,795, 2,069,796, 2,069,797, 2,069,798, 2,069,799, and 2,079,142.

In the patents referred to the drilling tools disclosed therein are weighty and bulky, and are therefore unwieldy in handling on the rig when attaching and detaching them from the drilling string. To obtain a workable tool that is easily assemblable and disassemblable many parts have been used both for maintaining the cutter assembly mechanism upon the shank and in providing a proper main bearing support for the carrier of the cutters. The use of so many parts possesses the disadvantage that discrepancies in manufacture are cumulative and will permit certain essential constituents of the bit to become loose where snug ts are preferable. Moreover, the use of many parts limits the placing of adequate flow channels for directing the stream of fluid to the bottom of the hole, and keeping it free from cuttings at all times while at the same time cleaning the teeth of the cutters While on bottom of adhering matter.

It is with the idea in mind of overcoming the disadvantages noted and others that the present invention is concerned. It therefore becomes an object of this invention to provide drilling bits of relatively light weight and thereby facilitate handling without diminishing their drilling capacities, or safety in their use.

A further object of the invention resides in the decreasing of the number of constituent parts of roller bits while` retaining ease of replaceability of their cutting elements.

A further object of the invention lies in providing an improved bearing for a roller drill bit whose component parts are readily assemblable and disassemblable.

Another object of the invention lies in providing an increased clearance of the shank portion of a bit in a hole so that the cutting elements thereof may not b e retarded in performing their functions.

Still a further object of the invention resides inthe ability to alter the clearance of the shank portion of the bit to render it usable in the drilling of bores of various dimensions.

Still a further object of the invention resides in an improved bearing in a drill bit having ease of assembly and disassembly, and also economy in the cost of its production.

Another object of the invention is to provide an improved bearing having roller or ball retaining means serving to lock a roller or ball race to a bearing supporting member.

Yet another object of the invention resides in the provision of an assembly in a roller type4 of drill bit in which the cutting portions of the bit are held together by welding some of the parts.

Another object of the invention lies in providing a construction for roller drill bits which will permit the use of a larger ow channel capable of directing iiuid to the bottom of the hole.

How the above and. other objects and advantages of my invention are obtainable will become apparent from a consideration of the following description taken in connection with the drawing, wherein:

Figure 1 is a longitudinal section of a preferred embodiment of my invention, parts being shown in elevation;

Figure 2 is a side elevation of the drilling bit illustrated in Figure 1 as seen from the right thereof Figure 3 is a transverse sectional view taken generally along the line 33 of Figure 1;

Figure 4 is the transverse sectional view taken along line 4 4 of Figure 3; and

Figure 5 is an enlarged perspective View of one of the buttons used for retaining the bearing balls in the raceways and for lockingone of the races to a bearing supporting member.

In general, the drill bit embodiment shown on the drawing includes a shank portion I and a cutter assembly II which is adapted to be rotatably carried. by the shank. The shank includes the usual threaded pin I2 and it also has two depending legs I3, I4 between which the cutter mechanism is supported. One of the legs I3 has integrally yformed therewith a bearing supporting extension I which makes an angle other than 90 with the longitudinal axis of the shank in order tha intermitten rolling cutters I6 can be had with the formation, and a consequent reserve of cutters be on hand at all times; all of which is explained in detail in my patents referred to and particularlylin Patents Nos. 2,050,988 and 2,069,799. The other leg I4 of the shank has a bore I1 therethrough for receiving the reduced cylindrical extension I8 of the bearing supporting member I5 which can be rigidly secured to the longer leg of the shank by the weld I9. 'I'he long leg I4 of the shank is initially separate from the remainder of the shank and is adapted to be slid uponA the reduced extension of the bearing supporting member in contact of the the manner just indicated with the upper portion 2| oi' the long leg welded to the shank body proper by the weld 2i. For the purpose of providing a greater welded surface and also preventing rotation of the long leg relative to the bearing supporting member the upper weld is in the form of a flat V, thereby providing an interlock between the long leg and the shank body.

Upon the bearing supporting member I I, an inner race structure 22 is adapted to be keyed. This inner race structure supports the cutter carrier 23 of the cutter assembly Il through the agency oi' the sets of balls 24 rotatable in the grooves 23 of the race in the inner bearing member 22 and also in the complementary grooves 26 oi' the outer race 21 formed integrally with the cutter carrier 23. The manner in which the balls are inserted into the respective races and the inner race keyed to the bearing supporting member will be explained hereafter. It is sunlcient to say at this point that the balls support the cutter carrier for rotation upon the inner race member while maintaining it in assembled position thereon, transmitting axial loads between the members and also radial loads.

The cutter carrier includes a plurality of slots 23 spaced around its periphery in each of which cutters i6 having teeth are positioned, being rotatably carried upon the bearing supporting pins 23 which are welded at their ends to the sides of the slots.

By the general arrangement just described each cutter has three degrees of freedom of motion; rstly, revolution about the axis of the hole; secondly, revolution about the inclined bearing supporting axis A-A; and thirdly, rotation about the axis of its supporting pin 29. By virtue of this arrangement the cutter carrier 23 will rotate about the inclined bearing axis A--A to bring each cutter successively into and out of formation contact because of the reaction of the cutters upon the hole bottom; which motion is induced by the rotation of the shank in the hole. The particular cutters in formation contact will break up the formation by their rolling action thereon about their supporting pins. In this manner, the underlying principles of this type of blt, as explained in my Patents Nos. 2,050,988 and 2,069,799, are effectuated.

For the purpose of keeping the cutters clean and free of detritus an upper nozzle 30 is threadedly held in the shank, communicatingwith a fluid passageway 3| extending through the tapered pin I2. It will be noted that this nozzle is positioned at an angle to the pin axis so as to direct a stream of uid partially tangentially and partially longitudinally of the roller cutters to cleanse them of adhering matter while rotating each cutter about its pin axis to insure a thorough flushing of all of the cutter teeth. In addition, as explained in my co-pending application No. 133,859, flied March 30, 1937, Drill bits", now Patent No. 2,118,542, granted May 24, 1938, the inclination of the nozzle also results in an impinging of fluid against the sides of the slots 28 to exert a force tending to rotate the cutter carrier 23 inthe proper direction about the inclined bearing supporting axis A--A to insure the `intermittent engagement and disengagement of the cutters with the formation.

'Ihe bottom of the hole is kept free from cuttings by the lower nozzle 32 screwed into the short leg I3 of the shank and having fluid conducted thereto through the conduit 33 having communication with the uid passageway 3| in the tapered pin I2. Because of the position of this lower nozzle and due to the fact that the drill bit forms a hemispherical or concave surface on bottom, the fluid issuing from it will impinge upon the hole bottom and be deflected and guided by it toward the other leg I4 of the shank and thence upwardly around the drill collar and drill pipe (not shown). In pursuing this motion the fluid stream will carry the cuttings away and at the same time will act upon the roller cutters i3 which are on bottom to prevent cuttings from adhering to their teeth and thereby impeding progress of the bit. This feature is claimed broadly in my co-pending application No. 161,484, filed August 28, 1937, "Means for circulating fluid around drill bits, now Patent No. 2,121,112, granted June 2l, 1938. However, it will be noted at this time that by forming the bearing supporting `member l5 integrally with the leg I3 of the shank instead of making it separately as disclosed in the application just referred to, a larger single conduit and nozzle can be used for directing its stream against the hole bottom; thus decreasing the frictional `resistance to flow of fluid through the conduit and nozzle to provide a greater volumetric discharge and also less wear upon the sides of the conduit and nozzle incident to the decreased side wall friction. The use of the integral bearing supporting member I5 thereby permits a single passageway and nozzle to discharge the greater volume of fluid, permitting the remainder of the leg of the shank to be made of adequate strength while using smaller dimensions. This is particularly true when the comparison is made with the necessity of using two separate ilow conduits in a single leg in order to obtain a proper volumetric discharge.

As aforementioned, the main bearing 22 is keyed to the bearing supporting member and balls 24 are introduced into the respective raceways 25, 26 to complete the bearing structure. In preventing rotation of the inner bearing structure 22 about the inclined axis A-A a keyway 34 is cut in the bearing supporting member i5 longitudinally thereof; and a radial hole 35 is drilled to the torlc surface of each bearing race 25 from the inner bore of the inner race structure 22. Buttons 36 serve to lock the inner structure 22 to the bearing supporting member I5 by having their rectangular bottom portions 31 slidable in the keyway 34 and their cylindrical parts 33 filling the bore in each of the generally radial holes 35 in the inner bearing structure. It will therefore be seen that the buttons lock the inner bearing structure to the bearing supporting member and also maintain the balls ln their proper rotatable position in the raceways.

In assembling the cutter carrier 23 with the cutters I6 thereon on the inner raceway structure 22, it is placed thereover with all of the buttons 36 removed from the inner raceway 22 and before any balls 24 are inserted therein. The balls are then placed through the respective holes 35 until the races are filled. whereupon a button is then inserted in each hole to prevent the balls from falling out of the raceways. After all of the raceways are thus filled up and all of the buttons are in place the entire bearing assembly can then be slid on the bearing supporting member I5 with the buttons 3l being guided in the keyway 34 for holding the inner raceway 22 from relative turning movement with respect to the bearing supporting member I I. Upon being thus assembled the long leg I4 is placed over the reduced extension I8 of the bearing supporting member with a boss 39 thereof abutting against the end face 4I) of the inner bearing vrace and pressing the other end face 4I against the integral boss 42 formed on the short leg I3 of the shank and adjacent to the bearing supporting member. Upon being held in snug engagement in this manner the terminal portion 43 of the reduced bearing supporting member extension is welded to the sides of the bore I1 in the long leg. This welding operationis of particular value since the snug engagement is maintained throughout the welding operation so that the cooling of the weld and its adjacent portions will produce a contraction of the metal tending to apply a compressive force pressing the inner bearing race against abutting bosses and insuring that axial play of the inner bearing race upon the bearing supporting member will be eliminated. l

After the reduced bearing support extension has been welded to the leg, the upper portion is welded by filling in the V groove formed by placing of the leg in its assembled position. By the use of the two welds a functionally integral shank structure is obtainable possessing great rigidity and compactness without sacrificing strength and safety.

For the same hole diameter the bit just de-` scribed is a fraction of the length of previous constructions and much lighter. It can therefore be handled easily on the rig for the purpose of fitting it to a drill collar and removing it therefrom. It further possesses the advantage that the compact and simpler design renders it possible to produce better distribution of iiuid around and through the bit without sacrcing strength. Moreover, the bearing construction is economical to manufacture and assemble, the buttons serving the two-fold function of not only keying the inner bearing race to the bearing supporting member but also maintaining the balls in their proper operative positions in the raceway. In connection with the latter element, although the buttons have been illustrated as being cut off at right angles to their cylindrical axes, if desirable, their ends can be made to conform with the toric surface on the inner raceway so that a smooth surface would be presented for the rolling of the balls thereon. However, I have found that a slight break in the continuity of the surface fails to impede the free rolling action of the balls in the raceway; and for that reason the simpler and cheaper construction of buttons is illustrated.

Apparently, this lack of impedance is aided bythe fact that the buttons and keyways are placed in a positon where there is a minimum of load on the ball races, and consequently, a minimum of wear. Such emplacement can be shitfed somewhat from the speclc location illustrated, since the area of minimum loading on the race 22 and the main bearing support I5 is of material angular extent, possibly extending upwardly from the position shown for about 90 to 120 degrees.

The use of the replaceable long leg I4 is associated with additional advantages regarding the range of application of the drill bit described. In my Patent No. 2,069,799, I have described and claimed a drilling bit using a single carrier which is mounted about an axis inclined to the shank axis. Rotation of the carrier is insured by maintaining the rollers when in their bottommost position to one side of the axis of the hole. In the patent, this has been accomplished by providing a thickened leg portion. The leg I4 of the instant application can laccomplish the same function, but due to the fact that itis replaceable, different leg thicknesses may be substituted forr it to vary the contact distance of the bottommost rollers from'the axis of the bore. The removable legiprovides a further mode of varying the contact distance merely by changing the position of the weld 2I, -as by moving the legv closer to or farther from the center line of the shank prior to welding. It is also apparent that the position of the weld can also be moved lengthwise with respect to the long leg of the shank.

Economy of manufacture and adaptability of the shank body I0 for use with various sizes of cutting assemblies is obtainable because of the replaceability of the long leg I4. Thus, a cutter assembly II of smaller diameter could be substituted for the one disclosed and the necessary` shank clearance maintained merely by substituting a long leg of thinner section for the one disclosed, or by moving it further inwardly prior to welding. Within reasonable limits, a cutter assembly of greater diameter could be substituted for the one'illustrated and the same size of leg, or a slightly larger leg, used which will preferably have its outer surface curved to the same radius as the radius of the hole; or the leg can be moved outwardly further prior to welding.

The arrangement shown can be disassembled very readily for insertion of a new cutter assembly on the shank. In pursuance of this object, the weld I9 inl the bore can be drilled out and the upper V-shaped weld can be cut through with a cutting torch, or any other convenient means. The long leg can then be slid off the reduced end of the shank and the entire bearing assembly and cutter carrier mechanism can then be moved endwise oiT the bearing supporting member. Removal of all of the buttons Will permit the balls to fall out of the bores 35; whereupon the cutter carrier can be removed from the` inner bearing race. A new cutter assembly can then be inserted over the inner bearing race; the balls reinserted through their respective bores; the buttons placed in the bores and the entire assembly slid onto the bearing supporting member with rectangular buttons portions riding in the keyway. The long leg that has been removed, or a different leg, can now be placed upon the reduced extension with its boss abutting the end of the inner bearing race, in the manner aforementioned, the reduced extension welded to the sides of the bore, and the upper leg portions welded to the shank proper. Thus, the entire shank and the inner bearing race can be used for a number of runs, decreasing the cost per run materially; While giving rise to a roller bit in which the shank is functionally integral.

While I have described my invention with particular reference to the form disclosed on the drawing it is to be understood that the invention is not to be limited to the particular drill bit shown but that various changes can be made without departing from the scope of my invention as dened in the claims appended hereto.

I claim:

1. An earth boring tool comprising a shank having a depending leg integral therewith, a bearing supporting member integral with said leg and extending therefrom, a second depend# 2. An earth boring tool comprising a shank having a depending leg integral therewith, a bearing supporting member integral with said leg and extending therefrom, a second depending leg welded at its upper end to said shank and welded at its lower region to said bearing member, a plurality of rolling cutters, and means supporting said cutters by said bearing member whereby they are adapted to intermittently contact the formation.

3. An earth boring tool comprising a shank having a depending leg integral therewith, a bearing supporting member integral with said leg and extending therefrom, a second depending leg welded at its upper` end to said shank and carrying said bearing member at its lower region, bearing means mounted on said bearing supporting member, and means including cutters rotatably supported on said bearing means.

4. in earth boring tool comprising a shank having a depending leg integral therewith, a bearing supporting member integral with said leg and extending therefrom, a second leg welded at its upper end to said shank and carrying said bearing member at its lower region, a bearing sleeve mounted on said bearing supporting member, a carrier rotatably supported on said sleeve, and a plurality of cutters rotatably mounted on the carrier.

5. An earth boring tool comprising al shank, bearing supporting means carried by said shank, a bearing race on said supporting means, cutter means including a bearing race, said races having confronting raceways, rolling bodies in said raceways for transmitting loads therebetween, said flrst-mentioned race having one or more bores through which said rolling bodies can be inserted in said raceways, and means afiixing said iirst-mentioned race to said bearing supporting means, said means closing said bores whereby to maintain said rolling bodies in the raceways.

6. An earth boring tool comprising a shank, bearing supporting means carried by said shank, an inner bearing race on said supporting means, cutter means including an outer bearing race, said races having confronting raceways, rolling bodies in said raceways for transmitting loads therebetween, said first-mentioned race having one or more bores through which said rolling bodies can be inserted in said raceways, means substantially lling said bores to maintain said rolling bodies in operative position in the racev bearing supporting means.

ways. said means amxing said inner race to nid 7.Anearthboringtoolasdei1nedinciaim8, wherein said last-mentioned means includes buttous nlling said bores, saidbearing supporting means being provided with a keyway receiving said buttons whereby to prevent relative rotation between said inner race and bearing supporting means.

8. An earth boring tool as defined in claim 6, wherein said raceways have generally toric surfaces, and said rolling bodies are spherical in shape. a

9. An earth boring tool comprising a shank having a depending leg integral therewith. a bearing supportingmember integral with said leg and extending therefrom, a second leg welded at its upper end to said shank and carrying said bearing member at its lower region, a bearing race mounted on said bearing supporting member, cutter means including a bearing race, said races having confronting raceways, rolling bodies in said raceways for transmitting loads therebetween, said mst-mentioned races having one or more bores through which said rolling bodies can be inserted in said raceways, and means afllxing said-mentioned race to said bearing supporting member, said means closing said bores whereby to maintain said rolling bodies in the raceways.

l10. An earth boring tool comprising a shank having a plurality of depending legs, supporting means integral with one of said legs and extending therefrom, means connecting said supporting means with another oi said legs, means including cutters adapted to rotate Vwith respect to said shank carried by said supporting means, and discharge means in one of said legs, said discharge means being in a longitudinal plane including the supporting means.

11. An earth boring tool comprising a shank l having a plurality of depending legs, support- J OHN A. ZUBLIN.

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