US2039551A - Rotary bit - Google Patents

Description

J. T. PHIPPS May 5, 1936.

ROTARY B IT Filed Oct. 29, 1954 2 Sheets-Sheet l o ml J. T. PHIPPS May 5, 1936.

ROTARY B I T Filed Oct. 29, 1934 2 Sheets-Sheet 2 Patented May 5, 1936 UNITED STATES uvuv- PATENT 'OFFICE ROTARY BIT Application October Z9, 1934, Serial No. 750,546

3 Claims.

My invention relates to rotary bits, and has particular reference to the cone-cutter type of rotary bits.

In earth boring it has been the common practice to employ a rotary bit for the purpose of digging the bottom of the hole and securing in the tool string above the bit a second instrument, or reamer, for the purpose of finishing off the sides of the earth bore and enlarging the same to the desired diameter.

Also. it is the common practice to employ a bit structure which includes a body having downwardly extending legs upon which are mounted a plurality of cone-cutters, the surfaces of which are formed with teeth to engage and cut formations by the rolling contact of the cone-cutter teeth upon the formation.

Heretofore the only manner in which such cone-cutters could be mounted upon the bit body was by mounting the cutter upon a. bushing which bushing was then screwed to a pin extending from the bit body, making it necessary that some locking means be employed between the bushing and the pin in order to prevent the cone from being lost from the body. Also the employment of cone-cutters on a bit constituting one tool and employing reamers upon a separate tool spaced a considerable distance to the rear of the cutting surface of the cone-cutters prevents the clean and rapid cutting of the cone-bit due to the fact that the lead which the cone-cutter has over the rearwardly spaced reamers is such that the reamers are required to cut surfaces of considerably greater area than would be required if the reamers were placed immediately adjacent the edges of the cone-cutters.

It is, therefore, an object of my invention to provide a rotary bit structure in which conecutters are mounted upon legs extending from the bit body, by attaching means which extend from the exterior surface of the bit body leg into the interior of the cone-cutter.

Another object of my invention is to provide upon a single tool a series of cone-cutters and a series of vertically rotated reamers so located relative to the cone-cutters that the cutting surface of the reamers engages the formation but a minute distance rearwardly of the cutting surface of the cone-cutters.

Another object of the invention is to provide a blt structure in which a single bit body is employed to mount both cone-cutters and reamers with the cutting surfaces of the cone-cutters and of the reamers in close relation to each other.

Another object o! the invention is to provide a bit structure in which a cone-cutter has embodied therewith a disc cutter rotatable upon the cone.

Other objects and advantages of the invention will be apparent from a study of the following specifications, read in connection with the accompanying drawings, wherein Figure 1 is a vertical elevational view of a bit structure constructed in accordance with my invention;

Figure 2 is an end view of the bit assembly shown in Figure 1;

Figure 3 is a vertical sectional view taken along line III-III of Figure 2;

Figure 4 is a vertical sectional view taken along line IV-IV of Figure 2;

Figure 5 is a horizontal sectional view taken along line V-V of Figure 4; and

Figure 6 is a detail view of a modified form of cone structure which may be employed with my invention.

Referring to the drawings, I have illustrated in Figures 1 to 5 a bit structure which comprises a body member formed of two complementary sections i and 2, assembled together with their meeting faces joined along the line indicated by the reference character 3, the body members are identical, each including two downwardly depending legs 4 and 5 so that when the body members are assembled as shown in Figures 1 to 5, the legs 4 of the two body members will lie on diametrlcally opposite sides of the Vertical axis of the tool, while similarly the legs 5 will lie on opposite sides of the vertical axis. The upper ends of the body members I and 2 are formed of complementary sections which together form a cone type pin permitting the connection therewith of the drill string employed to rotate the tool.

By referring particularly to Figure 3 it will be observed that the lower ends of the legs 4 and 5 are cut along a line extending at 45 to the axis of rotation of the tool to form a seating surface for the rear end of a cone-cutter 6 secured upon the legs 4 by means of a bearing pin l extending downwardly through the leg I at an angle of 45 to the vertical axis of the tool so that by forming the cone-cutter 6 with its outer surfaces arranged at 90 relative to each other the cutting edge 8 of the tool will lie substantially along a horizontal line while the opposite edge 9 of the cone-cutter will just clear a center line drawn through the vertical axis of the tool.

'I'he tool l may be of any suitable material inserted through an angular bore I0 and secured thereto by means of welding or any other wellknown method of securing metal parts together.

The pin 1 is illustrated as having its lower end reduced in diameter, as indicated at II so that a shoulder I 2 is formed thereon which constitutes an abutting shoulder upon which may be assema wear bushing I3 formed of any suitable hardened wear-resistant material, such bushing constituting a lining extending substantially over all of the surfaces of the pin upon which the conecutter 6 will bear. Similarly, a hardened seal washer I4 may be mounted upon the pin l to constitute a thrust washer against which the rear end of the cone 6 may abut to resist the thrust and wear upon the end of the leg 4. If desired roller bearings I5 and I6 may be interposed between the interior of the cone-cutter 6 and the wear bushing I3 to reduce the friction thereon.

With the construction thus far described the cone-cutter may be assembled upon the pin and its wear bushing from the lower end thereof and the cone-cutter may be held in place by a lock-pin I1 extending through a central bore I8 formed along the longitudinal axis of the pin l, the lock pin I1 extending into threaded engagement with the apex portion of the cone 6 as indicated at I9. The opposite end of the lock-pin I'I is illustrated as being formed with an enlarged head 20 receivable in an enlarged bore 2l in the pin I so that the head 20 bears upon a shoulder 22 formed between the two bores I8 and 2| and prevents any movement of the cutter 6 away from the pin 1. Th ook-pin Il is ri ered-Gathecutterjtorlota-teftll 'n il .h.means ofar s et screw 23 so that once assembled the cutter 6 and the lock-pin I1 rotate together.

By referring particularly to Figures 1 and 4, it will be observed that the legs 5, extending from the opposite body members I and 2, are provided with bores 24 which extend in parallel relation to the axis of rotation of the tool and constitute mounting devices upon which cylindrical reamer cutters 25 may be mounted upon bearing pins 26 which extend into threaded engagement with the bores 24. The bearing pins 26 are illustrated as being formed with enlarged heads 21 adjacent to which a radial recess 28 is formed to receive roller bearings 29, forming a rotating bearing surface upon which the cylindrical reamer cutters 25 may drop from above. The bearing pins 26 may then be screwed into the legs 5 with a wear washer 30 interposed between the upper edge of the reamers 25 and the lower surfaces of the legs 5. 'I'he bearing pins 26 are illustrated as having their upper ends formed with a radial groove 3l extending therearound, such radial groove constituting a recess relative to a horizontal bore 32 extending through the body member upon which it is assembled, so that bolts 33 extending through the bores 32 at right angles to the dividing line 3 of the body section may be employed for the double purpose of locking the bearing pins 26 in place in the tool, and for securing the two complementary halves of the body member together.

By referring particularly to Figures 3 and 4, it will be observed that the location of the reamer cutters 25, relative to the cone-cutters 8, is such that as shown particularly in Figure 4 the cutting line 40 of the cone-cutters is spaced but a minute distance below the lowermost cutting surface 4I of the reamer cutters 25 so that the reamer cutters in effect continue the cut of the cone-cutters with but a minute quantity of material separating the line of engagement of the cone-cutters with the bore from the line of engagement of the reamer cutters with the bore.

Likewise, by particular reference to Fig. 3, it will be observed that the sides of the reamer cutters 25 will cut along the line indicated by the reference character 42 which begins but a slight distance rearwardly of the cutting line of the cone-cutters and reams the hole substantially at the point of contact of the cone-cutters with the hole to the required internal diameter, the entire cut, both at the base of the hole and along the sides of the hole, occurring substantially simultaneously and with substantially little material interposed therebetween.

By the use of the construction set forth the reamer cutters 25 continuously clear the bore for the cone-cutters, removing the material from that part of the cone-cutters indicated by the arrow 43, which constitutes the greatest resistance and the greatest wear in the present type of conebits, while, at the same time, the cone-cutters substantially start the cut to be made by the reamer cutters since, from an inspection of Figure 4, it will be observed that the line of cut indicated at 40 curves at its end in conformity with the curved rear edges of the cone-cutters and substantially meet the cutting line of the lower ends of the reamer-cutters.

By referring particularly to Figure 6, it will be observed that the assembly of the cone-cutters upon the legs 4 by the employment of the bearing pin I and the lock-pin Il permits the ready separation of the cone-cutter 6 into two parts, 6a and 6b, the apex section 6a constituting the major portion of the cone extending from its apex, while the base section 6b constitutes in effect a disccutter mounted for rotation upon the cone section 6a. This construction may be readily formed by constructing a rearwardly extending boss 45 upon the cone section 6a which has an exterior surface concentric with the axis of rotation of the cone section 6a, upon which boss the section or disc 6b is mounted with roller bearings 46 interposed therebetween, if desired.

It will be noted from an inspection of Figure 6 that the teeth 4l, formed upon the section 6b, are curved to cut the exterior portions of the bore including the outer part of the bottom of the bore and a portion of the cylindrical side walls of the bore, and hence do not conform with or form an extension of the straight cutting line of the remainder of the cutter (that is of section 6a) so that there cannot be a true rolling contact achieved between the bore and the teeth of the section 6b if such section is rigid with the section 6a. Thus there would be a considerable dragging or scraping between the teeth 4l and the earth formation. By arranging the section 6b as a separate disc and mounting it for rotation upon the section 6a, it will be apparent that the section 6b can rotate independently of the section 6a and thus the teeth 41 will operate as true rolling teeth. Moreover, by mounting the section 6b for rotation on the section 6a, the differential cutter 6b will not be subjected to jamming and stoppage in the earth bore because even though such cutter 6b should bind upon its bearing surface that bearing surface, being a part of the rotating cone 6a, will be rotated and will tend to move or rotate the section 6b relative to the earth formation, thus assisting in the release of the section 6b should it be jammed in the earth bore.

With the assembly shown in Fig. 6 it will be observed that substantially all of the thrust on the cone section 6a will be taken up by the roller bearings I and I6, section 6b being subjected only to such resistance as is occasioned by its own contact with the earth formation.

While I have shown and described the preferred embodiment of my, invention, I do not desire to be limited to any of the details of construction shown herein, except as dened in the appended claims.

I claim:

1. In an earth-boring tool, a blt body, a cone cutter formed in two sections, an apex section for cutting the central portions of an earth bore and a base section for cutting the exterior portions of an earth bore, ans mounting said apex section of said cutter on/said bit body for relative rotation thereto, a cylindrical boss formed upon and extending rearwardly from said apex section to constitute a rotatable bearing member upon which said base section is rotatably mounted.

2. In an earth-boring tool, a. bit body, a cone shaped cutter formed in two sections, an apex section for cutting the central portions of an earth bore and a base section for cutting the ex- Uuml VH terior portions of. the bottom of the earth bore and the side wall oi said earth bore, means mounting said apex section on said bit body for rotation relative thereto, a cylindrical extension on said apex section extending rearwardly. thereof and concentric with the axis of rotation of said apex section to constitute a rotating bearing upon which said base section oi' said cutter ls rotatably mounted.

3. In an earth-boring tool, a bit body, a cone shaped cutter formed in two sections, an apex section for cutting the central portions of an earth bore and a base section constituting a rearward continuation of said cone and having teeth thereon deviating from the cone surface to cut the outer portion of the bottom of said bore and the side wall of said earth bore, means mounting said apex section on said bit body for rotation relative thereto, a cylindrical extension on said apex section extending rearwardly thereof and concentric with the axis of rotation ofl said apex section to constitute a rotating bearing upon which said base section of said cutter is rotatably mounted.

JOHN T. PHIPPS.

IIVV

Images