US 2807444 A
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Description (OCR text may contain errors)
Sept 1957 w. H. REIFSCHNEIDER 2,807,444
mam. DRILL Filed Aug. 31, 1953 mwsmv H. RF/FSCHNDDER INVENTOR.
ATTORNEY United States Patent WELL DRILL Winston H. Reifschneider, Houston, Tex., assignor to Hughes Tool Company, Houston, Tex., a corporation of Delaware Application August 31, 1953, Serial No. 377,372
3 Claims. (Cl. 255-313) This invention relates to rotary earth boring drills or bits and particularly to the jet type of well drill wherein nozzles are provided intermediate the cutters thereon so that flushing fluid pumped through the drill will issue from the nozzles in the form of jets which impinge directly upon the bottom of the bore being drilled.
It has been proposed to provide in earth boring drills or bits a hollow internal nozzle element having legs which extend downwardly through the bottom of the bit head and conduct flushing fluid in directions predetermined by the direction of the legs at the point of exit. Such a structure is illustrated in United States Patent to Collins No. 1,945,258, issued January 30, 1934. Such a construction requires an especially large cavity within the bit head to receive the nozzle element thus consuming valuable space and weakening the structure. Also limitation of space requires that the nozzle element be made as small as possible thus severely limiting the life of the nozzle itself and the bit of which it forms a part. This type of drill also presents manufacturing difliculties in that interior configurations are difficult to produce with desired accuracy that assembly is made easy and at the same time limited space is utilized.
The present invention comprehends and has as an object a novel bit structure which is relatively inexpensive to manufacture, overcomes difficulties indicated above, and which is particular efiiciently utilizes all space available thereby providing adequate strength to meet rigorous requirements of the bit when in normal use.
Another object is to provide a drill bit having a head made up of arcuate segments which are so constructed that, when assembled, a structure is had having adequate strength for supporting the rolling cutters thereon and at the same time the passageways therein for flushing fluid desirably direct the fiuid downwardly within the well bore.
Still another and more specific object of the invention is to provide a rotary earth boring drill in which the bit head is formed of a plurality of arcuate segments each of said segments being asymmetric and comprising a body portion having a downwardly extending leg and a downwardly extending hollow boss in side-by-side relation thereon, there being a passage communicating between the interior of the bit head and the bores of the bosses.
Other objectives and advantages will be more fully apparent from the following descriptions considered in connection with the accompanying drawings in which:
Fig. 1 is a side elevational view of an earth boring drill embodying the invention;
Fig. 2 is a horizontal sectional view taken on line 2-2 in Fig. 1;
Fig. 3 is a perspective view of one of the bit head segments of which a plurality are used in assembled relationship to provide the structure such as that shown in Fig. 1;
Fig. 4 is a perspective view of a modified form of bit head segment.
In Fig. 1 of the drawings the invention is shown embodied in a three-cone bit 1 comprising a bit head 2 made up of arcuate segments 3, 4 and 5 secured together by welds 6. Each of the arcuate sections has a downwardly extending leg 7 provided with an inwardly extending shaft 8 (Figs. 3 and 4), rolling cutters 9 being mounted upon the respective shafts of the bit 1 and suitable bearings being interposed between the rolling cutters and the shafts. The upper ends of the segments form the hollow pin 10 provided with threads 11 for attachment to the lower end of a drill string so that the bit may perform its intended functions.
One of the bit segments is shown at 15 in Fig. 3 and it is to be noted that such segment is a unitary structure which may be formed of a suitable steel as by forging or casting. The body 16 of the segment is generally arcuate in configuration and the central portion thereof has surfaces 17 and 18 converging at such an angle that, when a plurality of the segments are juxtaposed for assembly, the faces of adjacent segments are in engagement and the assembled segments form a complete bit head. It is to be understood that when the bit embodying the invention is a two-cutter construction each segment comprises a half bit head and hence the surfaces 17 and 18 merge into a common plane. If the bit is a three-cutter structure, as shown, the surfaces 17 and 18 converge at an angle of 120 and if the bit is a four-cutter structure, or has four legs extending downwardly to support the cutters, the surfaces 17 and 18 converge at an angle of The edges of the bit segment 15 are beveled as shown at 20 so that a welding groove is formed when a plurality of segments are placed in assembled relation. These grooves receive the weld metal 6 to produce integration of the bit head.
The upper portion 21 of each of the segments 15 is a pin portion and has a cavity 22 therein. The edges of the segments are likewise beveled at 23 so that grooves formed thereby enable the deposit of weld metal within the pin to assure that leakage between segments cannot occur and such feature also serves to strengthen the bit head strucutre.
Segments 15 are symmetric, that is to say, the bit leg 7 integral with and extending downwardly from the body 16 is displaced sidewardly of a medial plane through the segment. Also, at the opposite side of the body 16 and extending downwardly therefrom is a boss portion including a hollow boss 25 shown as provided with a wear resistant nozzle 26 suitably secured in its interior. A drilled passageway 27 within the body 16 extends from the cavity 22 to the nozzle 26 thereby providing a How passage for flushing through the bit head.
To assemble the hit 1 a roller cutter 9 is placed upon each of the shafts 8, suitable bearings being interposed between the shaft and its associated cutter, as is well known in the art. The segments are then assembled and held in assembled relation while weld metal is deposited in the grooves formed by the beveled edges 20 and 23. The pin 10 is then provided with threads 11 and the bit is ready for use.
The alternate construction shown in Fig. 4 is perferable in many cases, especially in bits of smaller sizes where space limitations are more exacting. In this embodiment the arcuate segment 15' is provided peripherally with bevels 20' and internally with bevels 23 to serve the purposes already described in connection with Figs. 1, 2 and 3. In this form the cavity 22' continues downwardly from the pin portion 21' and is bifurcated at its lower end forming lobular cavities 28 and 29. The walls of the cavity 28 merge smoothly into the bore 30 in the boss 25. It seems apparent that when a plurality of segments 15' are assembled to form a bit head the respective juxtaposed cavities 28 and 29 are complemental and form smoothly converging passageways or furcations from the interior of the pin to the respective bores 3|] in the bosses 25. These passageways are of relatively large cross section whereby the velocity of flushing fluid therein is low, such velocity increasing as the fluid approaches the bore 30 whence it emerges as a high velocity jet. Turbulence is thus minimized and the cutting action of the fluid upon bit parts is reduced to a minimum.
Attention is also directed to the fact that the bosses 25 are so located that the jets of flushing fluid issuing therefrom are directed downwardly intermediate adjacent cutters 9 so that these jets impinge directly upon bottom to effect a disintegrating action upon bottom and keep the bottom clean whereby the action of the rolling cutters 9 is highly eflicient.
Broadly the invention comprehends a new and improved earth boring drill or hit in which the bit head comprises a plurality of arcuate segments so constructed and arranged that there is provided a structure which overcomes deficiencies of prior art structures and which is capable of withstanding the rigors of normal use.
The invention claimed is:
I. In a rotary earth boring drill, a bit head comprising a plurality of substantially identical elongated segments arcuate in cross section secured together to form a hollow pin at the upper end of the head, each of said segments having a downwardly extending bit leg displaced to one side of a medial plane through the segment, and a downwardly extending hollow boss integral with the segment at the side opposite said bit leg, there being a passage in the head communicating with the interior of the pin and the bore in said boss, said leg and said boss extending in substantially the same downward direction.
2. In a rotary earth boring drill, a bit head comprising a plurality of substantially identical elongated segments arcuate in cross section secured together to form a hollow pin at the upper end of the head, each of said segments having a downwardly extending bit leg displaced to one side of a medial plane through the segment, each said bit leg having an inwardly extending cutter shaft and a cutter rotatably mounted thereon, and a hollow boss integral with the segment at the side opposite said bit leg, there being a passage in the head communicating with the interior of the pin and the bore in said boss, said boss extending in a direction to discharge drilling fluid to one side of said cutter and against the bottom of the well bore being drilled by the bit.
3. :In a rotary earth boring drill a bit head comprising a plurality of segments secured together and having downwardly extending legs with inwardly extending cutter shafts and rolling cutters rotatably mounted thereon, there being conduits in the bit head for supplying flushing fluid through the head between the cutters and against the bottom of the hole being drilled, each of said segments being elongated and having its downwardly extending leg displaced to one side of a medial plane longitudinally of the segment, and each of said conduits terminating at its lower end in a downwardly directed hollow boss integral with one of the segments and located on the segment at the side opposite the bit leg thereon.
References Cited in the file of this patent UNITED STATES PATENTS 1,747,907 Reed Feb. 18, 1930 2,039,551 Phipps May 5, 1936 2,201,570 Zublin May 21, 1940 2,676,790 Turner Apr. 27, 1954 2,692,117 Kucera et al Oct. 19, 1954