US3040825A - Drill bits - Google Patents

Description

J1me 1962 J. T. WILLIAMS 3,040,825

DRILL BITS J. T.WILLIAMS 5 anja A TTORNE Y United States Patent Ofiice 3,940,825 Patented June 26, 1962 3,048,825 DRILL BITS James T. Williams, 313 S. 3rd St., Tonkawa, Okla. Filed June 4, 1959, Ser. No. 818,029 2 Claims. (Cl. 175412) This invention relates to drill bits and more particularly to detachable blade drill bits. Drill bits of this type whether or not the blades are detachable are generally referred to in the art as drag bits. With drag bit construction the blade portions wear rapidly by abrasion against the earth formations and it is desirable to replace the blades while retaining or salvaging the body and other portions of the bit. Great difiiculty is encountered, however, in securely afiixing the blades to the bit body so as to avoid loosening of the blades due to the chattering of the bit.

It is not uncommon to conduct the drilling operation in the rotary method of drilling wells by applying weights approximately ten, twenty or even thirty thousand pounds to the drill bit by lowering the weight of the drill stem or operating pipe onto the bit. When it is considered that the bit may be rotated at fifty to one hundred revolutions per minute while having a tremendous weight of this sort applied to it, it seems obvious that the bit is chattering against the formation. This chatter action tends to loosen all previous types of detachable blade bits with which I am familiar, and the present invention therefore contemplates a particular arrangement of the structure whereby the blades are securely wedged in position and retained against loosening while under use under the most exacting conditions. Furthermore, any looseness between the blade and the body causes a large increase in the rate of wear of both the blade and the drill body. In addition looseness increases the tendency of the blades to break off in the well. Any breakage is objectionable because the broken part must not only be replaced but the broken part must be fished out of the hole before drilling operations can be continued. This, of course, is expensive and time consuming.

Since the inception of drilling, diificulty has been encountered in the wearing away of the cutting blades. With the advent of deeper drilling, considerable time is expended in removing the string of drill pipes, say from a or 15,000 foot hole by uncoupling the hundreds of sections of drill pipe which have been added so as to elevate the bit to the surface. The worn bit is then removed and a fresh bit attached whereupon the drill pipe is then lowered to carry the bit to the bottom of the well bores.

It had been found that in a majority of instances, there is practically no wear to the body of the drilling bit which is connected to the drill pipe and that practically the only wear occurs on the cutting edges or lower portions of the drilling bit. It is therefore a principal object of the present invention to provide a detachable blade bit that obviates the difficulties of the prior art bits.

It is another object of my invention to provide a bit having detachable blades which can be readily mounted and dismounted upon the drill body.

Another object of this invention is to provide a bit having detachable blades which can be easily replaced when worn with new blades. Other objects and advantages of the invention will become apparent when the following description is considered in connection with the accompanying drawings wherein:

FIG. 1 is an elevation of a bit constructed in accordance with my invention.

FIG. 2 is a cross-sectional view taken on the line 22 of FIG. 1.

FIG. 3 is an elevation of one of the detachable bits showing the vertical and horizontal ribs.

FIG. 4 is an elevation partly .in section of the drill bit.

In FIG. 1 the drill bit is caused to be rotated and the drilling mud is circulated through the passage 9 shown in FIGS. 2 and 4 thereof to discharge from the bit in order to accomplish the various functions of said drilling mud, such as carrying away of the cuttings, the cooling of the bit, the creating of a filter cake on the face of the well bore, and for maintaining the bore against caving, all of which are known in the art.

The bit body 3 also shown in FIGS. 2 and 4 is so constructed that it has a downwardly and outwardly tapered conical surface adjacent its lower end which is provided with longitudinal circumferentially spaced grooves 1 and horizontal groove 2 so as to form a blade segment supporting surface.

Each of the blade segments 4 has an outer arcuate surface 10 which is arranged to receive the inner conical surface of a clamping or driving collar 5. This collar slides over the shank surfaces 10 and upper edge 10a of drill bits segments 4 and is forced into position by a driving sub 12, FIG. 1, internally threaded to fit the threads 11.

The ribs 6 and 8 of the detachable blade 4 mate with the grooves 1 and 2 of the drill body. It should be noted that the rib 6 extends vertically on the inner shank portion of the detachable drill blade and is located at a point remote from the edges thereof. With this construction, the blade segments 4 are firmly clamped in position and are thus securely held.

Although I have illustrated my invention utilizing a drill bit having three detachable blades attached thereto, it will be readily apparent to those skilled in the art that the invention is equally applicable to a bit having four detachable bits. Also as is apparent the abrading and fracturing drill bits may be replaced with rock drilling bits and other types of drilling bits.

Broadly stated, the invention contemplates a detachable blade bit wherein the blades are secured upon the bit body by the wedging action of a clamping collar. In addition to the wedging action of the collar the drill bit body is provided with a plurality of circumferentially spaced longitudinal or vertical grooves and a circumferential groove intersecting the vertical grooves. The detachable bits are provided with a shank curved transversely to mate with a portion of the outer periphery of the tapered portion of the drill bit body. Vertical extending ribs on the shank portions of the detachable bits and spaced on the shank at a point adjacent one of the edges thereof are so shaped that they mate with the vertical grooves in the drill body. In this manner the direct thrust of the rotative force of the drill stem and drill collar against the clamping collar is transmitted to the blades and bit body by the clamping collar so that rigid securing means is provided.

While particular embodiments of the invention have been described, it will be understood, of course, that the invention is not limited thereto since many modifications may be made, and it is therefore contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention.

The invention having thus been described, what is claimed and desired to be secured by Letters Patent is:

l. A detachable blade rotary drilling bit comprising a tubular body having an upper end and a lower end and reduced in its outer diameter in upwardly spaced relation from its lower end to provide a downwardly and outwardly tapered conical surface, a plurality of circumferentially spaced longitudinal grooves in said conical surface and a circumferential groove in the outer periph- 3 ery thereof intersecting said vertical grooves, said vertical grooves having straight sides and being progressively deeper towards the lower ends thereof, a plurality of blades having upper shank portions and lower cutting portions, the shank portion of each blade being curved transversely to mate with a portion of the outer periphery of the tapered conical surface of the body and having a vertically extending rib therein located at a point remote from the edges of said shank portion shaped to mate with one of said vertical grooves to prevent turning of the blade in respect to the body, there being a blade shank over each of the vertical grooves in the body and said shanks being of a width such that the combined shanks encompass the tapered portion of the body, each shank being tapered toward its upper end, each shank also having a horizontal rib thereon of a size to mate with portion of the circumferential grooves in the tapered conical surface of the body, said horizontal nib being located on each shank to position the upper end of the shank in downwardly spaced relation from the downwardly tapered surface on the tubular body, said shank also having an inwardly extending shoulder spaced below said horizontal rib a distance to extend under the lower end of the body, sleeve means having a tapered inside extending downwardly and outwardly over the outside of said shank portions of said blades for restraining said blades to said tubular body and preventing movement of said blades in respectto said tubular body, and means connected to said tubular member for longitudinally thrusting said sleeve to the restraining position.

2. A detachable blade rotary drilling bit, comprising a tubular body having its outer diameter increased toward the lower end thereof forming a downwardly and outwardly tapered mandrel on the lower end portion of the body, a plurality of cutting blades secured around the mandrel, each of said blades having an upper shank portion and a lower cutting portion, each of said shanks curved transversely to mate with the outer periphery of the mandrel and said shanks being of a width such that the combined shanks encompass the mandrel, said shanks also being tapered upwardly and inwardly, each blade shank also having a vertical rib on the inner periphery thereof remote from either edge of said shank, said mandrel having a cooperating vertical groove in the outer periphery thereof, said ribs and said grooves having straight sides to prevent slippage between the blades and the body, sleeve means having a tapered inside extending downwardly and outwardly over the outside of said shank portions of said blades for restraining said blades to said tubular body and preventing movement of said blades in respect to said tubular body, and means connected to said tubular body for longitudinally thrusting said sleeve to the restraining position.

References Cited in the file of this patent UNITED STATES PATENTS

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