US2249578A - Roller bit - Google Patents

Description

July l5, 1941. J. T. PHlPPs 2,249,578

ROLLER BIT Filed Nov. 18, 1939 2 Sheets-Sheet l July 15, 1941. 1 T PHlPPs 2,249,578 i ROLLER BIT Filed Nov. 18, 1939 2 Sheets-Sheet 12 JZ f7 @27.2 f n i 5f ff [il f3 Patented July 15, 1941 UNITED STATESFPATENT OFFICE ROLLER BIT John T. Phipps, Huntington Park, Calif. Application November 18, 1939, Serial No. 305,118

4 Claims.

This invention relates to details of construction of roller bits for use in rotary drilling of Wells.

An object of the invention is to provide a bit in which the rollers can be readily replaced without welding and which at the same time Yis exceptionally strong and sturdy.

Another object is to provide a roller bit with demountable rollers which in assembly does not involve critical adjustments or movements, thereby adapting it for assembly in the eld by unskilled men.

Still another object is to improve circulation of the drilling iluld past the rollers, whereby they are kept clean of cuttings.

A more specic object is to provide an adjustable nozzle construction for directing the stream of drilling iluid past the rollers.

The manner in which the foregoing objects are achieved will appear from the following detailed description, with reference to the drawing of a specic embodiment of the invention, it being understood that various departures from the specific structures shown can be made without departing from the invention.

In the drawings:

Fig. 1 is a vertical sectional view through a roller bit in accordance with the invention;

Fig. 2 is a vertical sectional view taken at right angles to the view of Fig. 1;

Fig. 3 is a horizontal section taken substantially in the plane III- III of Fig. l; and

Fig. 4 is a detailed vertical section taken substantially in the plane IV-IV of Fig. 1.

Referring iirst to Figs. l and 2, the bit therein depicted comprises a body member I having a substantially tubular internally threaded upper end portion 2 adapted to be screwed into a drill stem. At its lower end the body member I divides into a plurality of outwardly diverging arms 3, 4, 5 and B. The arms 3 and 4 are juxtaposed to each other and support therebetween a cross roller assembly l. The arms 5 and 6 are also juxtaposed to each other and are displaced 90 from the arms 3 and 4. Arms 5 and' 6 each independently support a gauge cutter assembly 8, both of which are identical.`

Referring now to Fig, 1, the cross roller assembly includes a heavy cross pin I0, the ends of which are squared and fit snugly against parallel surfaces of the lower ends of the body arms 3 and 4, respectively. This pin ID is removably retained in position by alpair of screws IIv extending through the respective arms 3 and 4 and are screwed into threaded apertures I2 (Cl. Z55-71) provided therefor in the opposite end oi the cross pin I0. The outer ends of the openings in the arms 3 and 4 which receive the screws II are countersunk to receive the heads I3 of the screws so that the outer ends of the screws are substantially ilush with the outer surfaces of the arms 3 and 4. The heads I3 are provided with hexagonal socket openings I4 (Fig. 4) for the reception of a wrench.

A mainweakness of roller bits having demountable rollers has arisen from the difficulty of providing a rigid and positive connection between the roller-supporting pin and the body. In accordance with the present construction, I provide a positive lock for the pins II. Thus the head I3 of each pin II is provided with a plurality of radial holes I5 extending from the socket I4 to the exterior surface of the head and a recess I6 is provided in each of the arms 3 and 4. After the screws I I have been set up solid, by a wrench inserted in the socket I4, the screw is locked against loosening movement by inserting a pin I'I through one of the radial holes I5 and into the recess I6, the pin being inserted through the socket recess I4. To retain the lockpin I'I in position, a lock screw I8 is then screwed into a threaded aperture I9 provided in the screw II. This lock screw I8 has a head, the peripheral surface 2i)v of which is cylindrical and bears against the pin I1. Screw I8 is in turn providedy with a hexagonal socket 2| for the reception of a wrench. Obviously there can be no force tending to release the screw I9 so that it provides a positive lock for the retention of the lockpin I1. The latter, in turn, prevents any possible loosening movement of the associated screw II.

The cross pin I0 rotatably supports a pair of roller members 22, both of which are identical, and each of which is rotatably mounted on the pin IIJ by two sets of roller bearings 23 and 24, respectively, and a set of ball bearings 25. The two sets of roller bearings 23 and 24 are separated by a spacing washer 26 which is snugly tted to the pin lil and pressed thereon.

The ball bearings 25 constitute thrust bearings for preventing longitudinal movement of the rollers 22 on the pin I0 and transmit all thrust directly from the rollers 22 to the pin lli, thereby preventing wear between the outer ends of the rollers 22 and the inner surfaces of the arms 3 and'4.

It will be observed that the balls 25 are engaged half in a recess formed in the pin Ill and half in a recess formed in the inner surface 'of the associated roller 22. To provide for the infaces of the roller and plug 2'! are machined to form continuous flush surfaces. Thereafter,

prior to assembly of the roller 22 on the pin H3,`

the plug 21 is knocked out and the balls 25 are introduced into the race through the openingA When all the balls are in place, the plug 27 is reinserted with its outer surface flush with the adjacent outer surface of the roller 22, thereby insuring that the inner surface of the plug 21 is i'iush with the adjacent surfaces of the roller. The plug 2l may then be positively secured in place by welding along the externalv juncture line, as indicated at 29.

Obviously the entire roller assembly 7 consisting of the pin I-, the two rollers 22, the ball bearings V and the roller bearings 23 and 24 is readyfor assembly between the arms 3 and 4, andthe only operation necessary to change from a worn roller assembly to a new one, is to first remove the lock bolt lil-from the screws I I, then retract the lock pins ll through the socket recesses in the ends of thescrews ii, after which the screws ll may be removed by unscrewing them from the cross pin l. The insertion of the new roller assembly is accomplished by simply reversing the procedure described. f

The gauge roller assembly 8 consists of a cutting roller 3d, rotatably supported by roller bearings 3land ball bearings 32 on a two-part sleeve 33 which is threaded internally to screw onto a threaded stubshaft 34 rigidly attached to one ofthe arms 5 or 5. Stub shafts 34 may be secured to arms 5 and 5 by welding.

Tolock the sleeve 33 on the stub shaft 3d, a locking arrangement somewhat similar to that described with reference to the cross roller construction, is employed. Thus the shaft 3 is provided at its inner end with a threaded recess 35 for the reception of a screw 3S, the latter being of the type known as the Allen set screw having a hexagonal socket inits end for the reception of awrench. Extending radially from the threaded recess 35 are a plurality of holes 31, some of which are adapted to register with recesses 38 provided in the sleeveV 33. The sleeve 33- is iirst tightened on the stub shaft 34 by means of a suitable wrench engaged in'recesses 39 provided in the exposed surface of the sleeve. Thereafter a pair of pins iii are inserted through 'Lil the opening 25 into that pair of diametrically f opposite radial holes 37 which are aligned with the recesses 33. The lock pins are then retained in position by inserting the Allen set screw 3S and screwing it up tight. g

As previously mentioned, the sleeve 33 is formed in two pieces. The purpose of this is to provide for. assembly of the ball bearings 32 in the race,

half of which is formed in the inner surface of the cutting roller Sil'and the other half of which is formed in the outer surface of Vthe sleeve 33. The sleeve 33 therefore includes a first section 33a and a second section 3317 which are screwed together by means of cooperating threads 42 provided on the two members. When the parts arefscrewed up solidly together, shoulders i3 and 44 on the sections 33a'and 33h, respectively,` seat firmly together in a plane intersecting the ball race. Obviously, therefore, the balls 32 may be inserted in that half of the race formed in the roller Si] and the two sections of the sleeve 33 can then be entered into opposite ends of the roller 36 and screwed together to complete the ball race in the sleeve 33 and lock the roller to the sleeve. Since the threads in the inner surface of the sleeve 33, which engage with the threads on the in 34 are formed partly in the section 33a and partly in the section 33h, these two sections must always be assembled in the same exact relative positions if the threads in the two sections are to be continuous and are to fit the threads on the shaft 36. I insure that the threads in the two sections 33a and 33h will always be continuous by providing a positive lock between the sections 33a and 331) in the form of a set screw 45 which is screwed longitudinally through a threaded aperture provided therefor in the section 33h, the inner endof the screw engaging a recess 4S` in the section 33a. In manufacture before the recess li is formed in the member 33a and before thel threads are cut in the inner surfaces of the members 33a and 33h, these two members are screwed solidly together by means of their cooperating threads 42. Then the recess 46 is drilled through the' threaded aperture in the member 33h and the set screw 45 is inserted. Thereafter the threadv for engagement with the pin 34 is cut in both sections 33a and 332) in a single operation. The structure may thereafter be disassembled and reassembled as often as desired without in the slightest degree misaligning the threads in the i sections 33a and 33h, since by always relatively rotating the sections 33a and 33h to bring the recess-46 in alignment with the set screw 45 threaded into the section 33h, the original relative position is restored.

As is well known roller bits are commonly secured to the lower end of a hollow drill string through which drilling fluid is continuously pumped, and some form of nozzlemeans is commonly employed to direct the drilling uid at high velocity onto thev drilling cutters tov keep them clean. Heretofore the nozzle means employed have usually been fixed (that is not adjustable), and have directed the drilling fluid in either fiat or solid, round streams against the "cutting rollers. In accordance with my present invention, I provide for the discharge of a concentrically continuous` diverging stream of fluid which is directed substantially toward the bottom corner of the hole' being drilled, this hollow diverging stream intercepting the gauge rollers 32' and the outer ends of the cross roller 1. I provide additional jets-for washing the inner portions-of the roller' sections- 22.

To produce the-foregoing effects, I provide in 4the upper portion of the body I four uniformly spaced fluid passages 50 symmetrically positioned about a central passage 5I which receives a bolt 52. At thelower ends the four passages 5i) and the passage 5l terminate in a large cylindrical passage which at its lower edge merges into a diverging passage 54 of conical shape, this passage terminating at the lower central surface of the body member l4 immediately above the cutting roller'. Y

Fluid enters the upper ends of the passages 5G' from thehollow drill stern and passes through the cylindrical' passage 53l and the conical passage 54. To distributethe fluid at high velocity in the desired manner, I provide a circulation bean`55 which is' substantially'ofconcal shape and is supported upon the lower end of the bolt 5,2. Thus, as clearly shown in Fig. 1, Ythe bolt 52 is threaded into the upper end of the bean 55 and is also screwed into threads 56 provided in the lower end of the holes The upper end ofthe bolt 52 is threaded and provided with a lock nut 51 which secures the bolt 52 in any position into which it may be set.

The outer surface 58 of the bean 55 extends parallel to the juxtaposed conical surface 54 and the space between these two surfaces may be varied by raising or lowering the bean to any desired extent. In a 121/2 inch bit I have found it desirable, ordinarily, to space the surface 58 from 1% to of an inch from the surface 54.

The conical surface 58 of the bean 55 is interrupted by two diametrically opposite vertical grooves 60, which grooves provide for the supply of a stream of fiuid to the central portion of the cross roller assembly 1. Obviously, therefore, the bean 55 is locked in such position that a plane extending through the two grooves 50 intercepts the axis of the cross roller assembly 1. As shown in Fig. 2, the lower portion of the bean 55 at points displaced 90 from the grooves 60 are cut away to provide ample clearance with the gauge cutters 8.

In the particular construction disclosed, the lowermost portion of the bean 55 extends below the level of the uppermost portions of the rollers 8 so that adjustment of the bean 55 (obtained as previously described by rotating the bean and the bolt 52) must be effected before the gauge cutters 8 are installed. However, by making the bean 55 slightly shorter it can be rotated to effect adjustment after the roller cutters have all been assembled.

The circulating system described has been found very effective in practice and in preventing fouling of any portions of the cutting rollers.

The adjustable feature is important, because, in order to obtain the greatest cleaning eiiciency from the circulating fluid, it should be delivered at high velocity and high volume. Under conditions where the supply of iiuid is limited, a smaller opening is desirable than where a larger supply of fluid is available at the bit. Thus, if the opening is too small for the supply of fluid available, the volume of flow is unnecessarily restricted. On the other hand, if the opening is too large relative to the supply of fluid available at the bit, then the velocity of discharge is unnecessarily low.

A very important feature of the invention is the construction involving the screws l2 for supporting the cross shaft l0. It permits of the use of a sturdy shaft of large diameter which is very resistant to bending. It is also advantageous to use tapered screws I2, as shown, because this increases the thickness of the pin surrounding the inner portion of the screw. The fact that the heads of screws I2 seat tightly against the shoulders at the bottoms of the countersunk portion of the arm apertures and clamp the arms tightly against the fiat end surfaces of the cross shaft, also contributes substantially to the rigidity of the arms and shaft, since they reinforce each other. The heads of the screws I2 are preferably fitted snugly in the arm apertures to prevent lateral movement therein.

At its midpoint, the cross pin I0 may be provided with shallow holes 90, for engagement by a suitable wrench to hold the shaft from turning when removing the screws I2, although this is not ordinarily necessary.

Obviously many changes may be made from the particular construction described in detail, which is merely illustrative of the invention, and the invention is therefore to be limited only to the extent set forth in the appended claims.

I claim:

1. A roller bit comprising a body member attachable at its upper end to a hollow drill stem and having adjacent its lower end a plurality of diverging arms supporting cutting rollers, said body member having a longitudinal fluid passage therethrough, the lower portion of said passage being of substantially circular cross section, a baule member supported from said body member and positioned within said lower portion of said passage and defining therewith an annular nozzle for the discharge of fluid.

2. A roller bit as described in claim 1, with adjustable supporting means for vertically adjusting said baiile member -to vary the opening of said nozzle.

3. A roller bit comprising a body member attachable at its upper end to a hollow drill stem and having adjacent its lower end two pairs of juxtaposed arms, one pair supporting a crossroller cutter and the other pair supporting gauge roller cutters, said body member having a longitudinal fluid passage therethrough, the lower portion of said passage being of substantially circular cross section and terminating above the level of said roller cutters, a baille member supported from said body member and positioned within said lower portion of said passage and defining therewith an annular nozzle for the discharge of fluid onto said rollers, said baffle member having slots therein, which slots lie in a vertical plane extending through the axis of said cross roller to provide additional jets of uid on the cross roller intermediate the end portions thereof.

4. A roller bit as described in claim 1, in which said longitudinal fluid passage comprises a single large passage at the lower end, and a plurality -of passages spaced from the central vertical axis of the body member, at the upper end, and bolt means centrally secured to said body member between said plurality of fluid passages therein and supporting said baffle member.

JOHN T. PHIPPS.

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