US2177334A - Cross roller earth boring drill - Google Patents

Description

' Oct. 24, 1939.

c. E. REED 2,177,334

CROSS ROLLER EARTH BORING DRILL Filed May 23, 1938 2 Sheets-Sheet l 31w WM:

Clazence EReed,

Gianna/1344 Oct. 24, 1939. c. E. REED 2,177,334

CROSS ROLLER EARTH BORING DRILL Filed May 23, 1938 2 Sheets-Sheet 2 Patented Oct. 24, 1939 R I MAY 16 1940 UNITED STATES CROSS ROLLER EARTH BORING DRILL Clarence E. Reed, Wichita, Kana, assignor to Chicago Pneumatic T N. Y., a corporation 00] Company, New York, of New Jersey Application May 23, 1938, Serial No. 209,563

Claims.

The invention concerns an earth boring drill and is disclosed in connection with the general type known as a cross roller bit in which a plur'ality of roller cutters are arranged in the same diametrical plane and cut the major portion of the formation, and inclined side cutters arranged in a diametrical plane substantially at right angles to the plane in which the first mentioned cutters are located, cut the area at the margin of the bottom of the hole being bored.

One object of the invention is to provide a cutter assembly which will stand up to its work by taking care of end thrust of the cutters, thereby eliminating or reducing to a minimum the wear due ordinarily to said end thrust, and preventing the formation of tapered holes which require reboring at great expense.

Otherobjects will be clear from the following disclosure.

It will be, understood that while the invention is illustrated in connection with an earth boring drill of the cross roller type, it is not limited as to all of its aspects thereto.

In the drawings Figure 1 .is a central vertical sectional view of one half of a drill bit head, showing one of the side roller cutters and its spindle and roller bearing assembly.

Fig. 2 is a central vertical sectional view of a bit head in a plane a quarter turn from the plane of section of Figure l, and showing a pair of roller. cutters arranged substantially end to end in axial alignment, and constituting the cross roller assembly per se.

Fig. 3 is a side view of one of the spindle members of the assembly shown in Figure 1.

Fig. 4 is a side view of the other spindle mem ber belonging to the side roller cutter organization of Figure 1.

In these drawings, l indicates the main body of a bit head of substantially ordinary form having a threaded shank 2 for attachment to a drill stem. As in usual practice, the bit head is hollow to receive flushing fluid which is directed through openings 3 and 4 to the toothed roller cutters to keep them free from accumulations of the cut formations, and to cause the discharge of said material from the bore hole. r I

A strut 5 depends from the lower face of the bit head being formed desirably integral therewith. Main spindle units as shown in Fig. 2 marked 6, 1 are arranged below the lower face of the bit head, each having a shank or hanger portion 8. seated in a recess in the side of the bit head wherein it is weldedyas shown at 9, said spindle member and shank preferably being formed in one piece. The spindle members 6 and l have each a reduced diameter part 6a, Ia substantially meeting ,at their end faces, the separation between them being slight but adapted to receive welding mate- 5 rial by which the two spindle units may be con nected. The two cutter units of Fig. 2 provide what are usually called the cross roller cutter, made up of substantially cylindrically shaped cutters 9 and I0 toothed on their exterior to per- 10 form cutting actions on the formation. This toothed formation may assume various forms, but

in the particular assembly illustrated, each may consist of two circular rows of teeth a at the outer end portion of the cutter, a single row of teeth I) at the inner end of the cutter, and a spiral rib 0 having a number of turns about the cutter and occupying the space between the circular rows of teeth a, b, the' purpose of this toothed arrangement being to provide efiicient means for breaking up or disintegrating the formation as rapidly as possible.

The spindle assembly for the cross roller cutters 9 and I0 include similar features, and it will be sufficient to describe one of said assemblies. Re- 5 ferring, therefore, to the righthand assembly in Fig. 2, it comprises the main spindle portion 1 of' comparatively large diameter and its extension la of reduced diameter, and annular flanges ll, l2, and I3. The flanges II and I3 present on one side, surfaces lying in planes at right angles to the axis of the spindle, and thus furnish the end walls of raceways for cylindrical roller bearings M, which find complementary surfaces upon which to roll on the bore wall of the roller cutter l0 and on the cylindrical periphery of the spindle I. The flanges II also present frusto-conical surfaces l5 which form walls of frusto-conical raceways, the complementary frustoeconical raceway surfaces of which are on the bore wall of the cutter and on spindle portions adjacent the ends of the roller cutter.

These frusto-conical raceways receive frustoconical roller bearings l6 and H. The larger diameter ends of those marked I! are directed outwardly from .the vertical axis of the drill, and hence take end thrust of the roller cutter in a direction radially outward from the center of rotation of the drilL Those frusto-conical roller bearings marked I6 take end thrust of the roller cutter ID in a direction inwardly towards the vertical axis of the drill.

Both sets of frusto-conicalroller bearings take thrustsof the roller cutter radial to the axis individual to said -cutter,,and also some of the upthrust from the bottom of the hole. The major portion of this upthrust or radial thrust of the cutter is borne, however, by the two sets of cylinder roller bearings ,Il in the cylindrical raceway divided by the annular flange l2.

The frusto-conical raceway for the frus'to-conical bearing rollers I1 is formed in the base or enlargement l8 integrally connecting the side hanger or bracket 8 and the spindle portion 1, said enlargement or base member being undercut at [5a to furnish the outer wall of the raceway of which the surface IIa furnishes the frusto-conical bearing surface.

The frusto-conical raceway for the frusto-conical roller bearings I6 is provided by the separate spindle member or collar 16a having a central opening to fit the reduced diameter portion Ia of the spindle member I, an undercut surface lBb serving as the defining wall of the frusto-conical raceway at the large diameter end of the frustoconical roller bearing.

The spindle section Ilia has a cylindrical exterior which fits in part into the cylindrical counterbore Illa at the inner end of the roller cutter. This collar or spindle section also fits in part in a recess in the strut or bridge piece 5. This recess may be in the form of a downwardly open notch 5a in the lower edge portion of said bridge.

The spindle section or collar lib fits against a similar spindle section or collar belonging to the spindle assembly of the lefthand cross roller cutter! of Fig. 2. These collars may be welded together. I

The spindle and roller bearing assembly for the, cross roller cutter 9, Fig. 2, is substantially the same as above described, the main difference being that the cutter 9 is shorter than the roller cutter l0, and hence one set of cylindrical roller bearings Ila are used instead of two spaced apart rows, as in the case of roller cutter Ill.

Referring to. Figure 1, which shows one of the side roller cutter assemblies of which, as in ordinary practice, there are two located in a vertical plane 90 from the plane of Fig. 2, it will be noted that the side roller cutter I9 is mounted to rotate in a plane inclining downwardly and outwardly in relation to the vertical axis of the drill indicated at a:-:r. This roller cutter is generally of cylindrical form having peripheral teeth for disintegrating the formation.

' These side roller cutters determine the diameter of the bore hole, it being noted that they cut clearance beyond the outermost surface of the bit head, or the brackets 8 or 8a thereof. It is important' that end thrust of these cutters be taken care of to the fullest extent. In. carrying out this object, as well as to secure long service of these side cutters, the body of the cutter is made wider than the toothed surface, for which purp se an extension or hub portion is provided at 20. By this addition, a longer bore is provided within the cutter than in ordinary practice, and I am thereby enabled to employ a frusto-conical raceway surface ateach end of the bore of the cutter, in addition to a cylindrical raceway surface, said surfacesbeing marked 2|,

22, and 23, Fig. 1. Roller bearings are provided.

at 2la, 22d, and 23a conforming to these raceway surfaces, those marked 2la and 2211 being' frusto-conical with their larger diameter ends directed in opposite directions, so that end thrust of the cutter in either inward or outward direction relative to the vertical axis of the drill will be taken by either one or the other of said frusto-conical roller bearings. Radial thrusts of the roller cutter and upthrusts from the bottom of the bore hole will be taken mainly by the cylindrical roller bearings 23a, and as the frusto-conical roller bearings thereby will be relieved of the major portion of these upthrusts and radial thrusts of the cutter, the said frustoconical roller bearings will have a longer life than if they took all thrusts imposed upon the cutter, including the end thrusts. With my present improvement, the side roller cutters will maintain their position relative to-the prescribed diameter of the bore hole by reason ofthe frusto-conical roller bearings standingup to their work for a larger period of time owing to being relieved in large measure by the cylindrical roller bearings from radial and upthrusts. 'By

maintaining their prescribed positions, said side roller cutters will prevent the formation of a tapered bore hole, and the great expense of reboring to eliminate the taper.

The roller bearings of these-side cutters run in raceways of a spindle assembly consisting of a main cylindrical spindle section 24, a flange 25 defining on one side the wall of a cylindrical raceway for the cylindrical roller bearings 23a, and presenting on its other side the inclined shoulder 26, defining the inner limit of the; frusto-conical raceway 21, the other side of! which is furnished by undercutting the shoulder or base 29, as at 28, of the hanger or bracket 8a, which, as in ordinary'practice, is welded or secured to the outer side of the bit head'l.

Thespindle assembly is completed by a spindle member adapted to be slipped onto the main cylindrical part 24 of said spindle assembly. This collar member or removable spindle section is shown in side view in Fig. 4, and in section in Fig. l, the latter figure showing it in its assembled relation to the main spindle portion. It has a cylindrical body part 24a, a flange 250. with an inclined side 26a, defining the inner limit of a frusto-conical. raceway surface 21a, also a flange 29a undercut to provide an inclined shoulder or bearing wall 28a. This formation provides the cylindrical raceway for the roller bearings 23a and the frusto-conical roller bearings 22a.

It will be noted that in devising the roller bearing assembly associated with the side roller cutter, I not only form the body of said roller cutter with a hub extension 20 on one side, but I take advantage of the full length of the bore wall of the cutter. In other words, the outer edge of the frusto-conical raceway surface of the bore wall coincides with the edge of the bore. This enables me to space the sets of frusto-c'onical cutters apart a suflicient distance to accommodate the cylindrical roller bearings and the raceway structure of the spindle for all of the sets of roller bearings.

In both assemblies of roller bearings, i. e.,- of Fig. 2 as well as in Fig. 1, the employment of the cylindrical roller bearings in association with the two sets of frusto-conical roller bearings which take the end thrusts, largely relieves these sets of frusto-conical rollers of wear, thereby enabling the latter to maintain the roller cutters in their prescribed relation to" the center of the bore hole, with the result, in respect to the side roller cutters, that the prescribedsdiameter of hole will be maintained instead of producing a tapered'hole, and in respect to the cross 'roller cutters, the result will be that said cutters will traverse their prescribed paths during 36 mately horizontal axis, a toothed roller cutter the eifectlve life or the cutter teeth, and wobbling of .thedrill bit as a whol will be prevented.

I'claim: a 1. A roller cutter'for an earth boring drill having a toothed exterior and a bore substantially longer than the width of the cutting surface,

said bore having roller bearing raceway surfaces, one at each end portion of said bore tapered inwardiyoi the cutter and providing bearing surfaces for frusto-conical roller end thrust bearings, said tapered end portions terminating substantially in the planes bounding the ends or said cutter bore.

2. A cross roller cutter assembly comprising a bit head having a centrally disposed depending strut provided with an opening, a main spindle member on each side of the strut, removable spindle members substantially abutting each other in the opening of the strut, each of said removable members having a portion, contacting the strut, and a tapered raceway racing outwardly, and each having a recess disposed sub-- stantially centrally thereof, said main spindle portions having projections-on which the removable spindle portions are mounted by said recesses, said main spindle portion having a flange adjacent thetapered raceway to provide a wall therefor, tapered end thrust roller bearings in said raceway, a cutter on the spindle mounted on said roller bearings, and a support at the outer end of each main spindle member, substantially as described.

3. An earth boring drill oi! the cross-roller type comprising a spindle, means engaging the ends of the spindle for supporting it on an approxisurrounding and rotatably mounted on the spindle, two spaced sets of rrusto-conical roller bearings, one set adjacent each end of the spindle and between the cutter and spindle, said sets' of roller, bearings tapering in opposite directions whereby to sustain horizontal thrusts on the cutter in opposite directions and a part oi. the vertical thrusts, a set of cylindrical roller-bearings positioned between said i'rusto-conical bearings,

whereby to sustain vertical thrusts on the cutter in a direction perpendicular to the axes of the cylindrical roller bearings, and complementary raceways in the cutter and spindle respectively for said roller bearings.

4. A roller cutter and spindle assembly for an earth boring drill, said cutter having a toothed exterior and a bore longer than the width of said toothed exterior, a set of frusto-conical and thrust roller bearings at each end of the bore, a frusto-conical raceway surface at each end of said bore, for said end thrust bearings, a

spindle support and a spindle having raceway 1 surfaces, one for each of said sets of frusto-conical roller bearings, said spindle raceway surfaces lying partly outside the planes bounding the ends of said cutter bore, said bore and said spindle having each a bearing surface of substantial width intermediate the said frusto-conical raceway surfaces.

5. A roller cutter and spindle assembly for an earth boring drill. according to claim 4 in which the spindle comprises a main section and a removable section connected therewith, the said main section having a shoulder undercut beyond raceway and the said intermediate bearing surfaceof the wall of the cutter bore, the flanges of said spindle section providing walls defining the limits of the cylindrical raceway and between which walls the cylindrical anti-friction roller bearings are guided, substantially-as described.

CLARENCE E. REED.

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