US2080117A - Roller shoulder bit - Google Patents

Description

y 1 937. c. A. DEAN 2,080,117

ROLLER SHOULDER BIT (yaw/es ,4 060,2

Patented a] 11, 1937 I UNITED STATES PATENT OFFICE 2,080,117 ROLLER SHOULDER m Charles A. Dean, Bakersfield, Calif. Application August 1, 1935, Serial No. 34,186

10 Claims.

'which as a whole is free-cutting and in which 10 cross-drag and wear are minimized; and further in which the working stresses are balanced so that it is feasible to mount the cutters on roller or other low friction bearings. An important purpose is to provide a bit that effects relatively rapid 15 initial penetration of a deflected side wall, followed by progressively increasing side thrusttoward the new cut so that the bit will tend to dig itself in to the new wall.

A further object is to obtain improved arrangement and mounting of cutters so as to steady a drill in operation and minimize deflection of an established bore. further description herein of preferred embodivention comprises features of construction, combinations of elements and arrangements of partswhich will be exemplified in the constructions hereinafter described and of which the scope of 30 application will be indicated in the appended claims.

In the drawing, which illustrates one preferred embodiment of this invention, Fig. 1 is a bottom or inverted plan view of the drill bit and roller 35 cutter assemblyf Fig.- 2.is an elevation of the bit with cross-section through conoidal cross-roller cutters of the bit; and Fig. 3 represents an elevation, partly in vertical section, of one of the longitudinal cutters of the bit, viewed at a right angle 40 to Fig. 2 along the plane 3-3.

This invention advantageously embodies a bithead in which are combined cross-roller cutters of conoidal form, preferably, having upwardly and inwardly inclined cutting surfaces, and longitudi- 45 nal roller cutters having tangentially inclined side cutting surfaces and having bottom-cutting teeth adapted to effect a leading 'cut into part of the,

bottom formation below the cross-roller cutters. This combination penetrates initially into a de- 50 flected wall in a wedge-like arrangement of cutting teeth and then advances with increasing cutting effect and side pull as the inclined longitudinal roller cutter is rotated against the bottom of the new cut. The rollers preferably are dis- 56 posed symmetrically in the bit to promote decutters 5 contain bottom-cutting teeth H.

Other objects will appear with velopment and maintenance of a straightbore V hole.

Referring more particularly to the drawing, the bit-head comprises a shank I adapted for engagement with the usual rotary drill stem. The shank 5 terminates in downwardly projecting arms 2 and 3 adapted to carry roller cutters- These cutters comprise conoidal cross-roller cutter 4 and cylindrical longitudinal roller cutter 5. Longitudinal The cross-rollencutters and the cylindrical longitudinal roller cutters are'adapted to ream some portion of the side wall, but the cross-cutter .4 is adapted to function as leading cutter at the bottom edge and lower part of the side or periphery. as illustrated by the cut shown in Fig. 3, while the' a cylindrical cutter 5 is adapted to function as leading cutter at an inner portion of the bottom after a new out has been initiated. This arrangement facilitates initial penetration into the side of a deflected bore.

As shown in Fig. 2, cross-roller cutter 4 is mounted with roller-bearings 6 on spindle I and is locked thereto by screw [4. Spindle 1 projects inwardly from arm 2 and may be horizontal or may be inclined. The shape of roller 4 preferably is frustro-conical with inwardly and upwardly inclined bottom-cutting teethd. The base of roller 4 faces outwardly of the bit, and is provided with teeth 9 adapted to operate outwardly of the arms 2 and 3. Preferably this toothed portion 9 of the base of cutter 4 intersects bottom teeth 8 at an acute angle, and the cutter 4 is mounted so that thisedge'of intersection between teeth 8 and 9 constitutes a wedge-like cutting element at the 5 periphery of the bore. This edge is to constitute the leading contact with the bore wall, as shown in Fig. 2 and shown also by the cut in Fig. 3. Teeth 9 preferably cut the side of the bore substantially vertical, while teeth 8 in combination 40 therewith tend to form a recess or a trough at the bottom edge, as illustrated in Fig. 3. Thus'when the drill is lowered into a deflected bore hole and is rotated, cross-roller 4 tends readily to embed itself in the lower wall, such as wall 1 0, and start a vertical bore. As a shelf is cut into the deflected side, and the. cutters penetrate further, there is continual side thrustto work the drill into ,the new bore. The bottom ,cutting teeth may be notched to augment the side thrust.

The rotating drill penetrates thedefiected wall by continued chipping action, effected initially by teeth 8 and 9 of the conoidal cross-rollers 4, and subsequently also by the bottom teeth 1 l on longitudinal rollers 5. Low friction mounting of the roller cutters 4 and 5 from arms 2 and 3 respectively, such as with ball bearings 6 of cutter 4, tends to promote a multiplicity of chipping cuts rather than a dragging action. As the bit is rotated in clockwise direction, the individual teeth 8 and 9 of cross-rollers 4 are brought into action in opposite direction. These cutting teeth build up in the bore vwall the shoulder or shelf having an upward slope into which the cross-rollers gradually settle.

As the conoidal cross-rollers 4 sink into the defiected wall, the vertical edges of longitudinal roller cutters 5 take up a reaming action along the upper side wall of the new cut. Cutter 5, as

shown, is inclined tangentially with its top about 20 preferably in a rearward direction from top to bottom having regard to the direction of rotation. Thus cutter 5 is given a twist in its reaming cuts. Also by this inclination of roller 5 its bottom cutter edges ll descend to a lowermost point centrally of their forward edge. This is illustrated in Figs. 2 and 3. In Fig. 3 a vertical section through this cutter 5 converges at tooth l2. The cutting elements of cutter 5 at the peripheral edge of the new drill hole are preferably above the corresponding peripheral cut of the conoidal cross-rollers 4. Thus, as the longitudinal roller cutter 5 comes into action to cut the bottom, the bottom conformation of the bore becomes that of an upward and inward slope containing an arcute or dished out, deeper toward the center of the bore, as illustrated in Fig. 3.

The inclination and position of longitudinal cutter 5 serve to introduce this cutter gradually into the sloped bottom that is formed by conical cutter 4. The bottom-cutting teeth of the longitudinal cutter 5 effect a leading cut into an inner part of the bottom formation below the cross-roller cutters 8, and in eifect thus become driven cutters, but maximum penetration and cutting action of cutter 5 in this sloped bottom is thus attained gradually after the conoidal cutters 4 have initiated a cut in the deflected side wall. The maximum bottom-cutting action of cutter 5 occurs at the inner side of its individual axis, as illustrated in Fig. 3. Cutting resistance on the bottom of this longitudinal cutter, thus predominant at its inner periphery, rotates cutter 5 on its individual axis as the drill rotates, and thus accelerates the chipping action of this longitudinal cutter both on the bottom and on the side wall. As a result partly of the upward inclination of the new. bottom cut toward the center of the bit, combined with the delayed and gradual introduction of the longitudinal cutter into the cut, the bit rather than being forced away from the cut is gradually drawn into the new shelf. After the bit has progressed into the deflected wall to a point beyond the center of the bit, the conformation of the cut is symmetrical and is of counterbalancing or stabilizing effecton both the bottom and sides of the bit,

This facilitates the use of low friction bearings and freedom of rotation of the individual cutters. Consequently, as illustrated in the drawing, the cutters tend to chip into the cleared portion of a cut. The conoidal cutters tend to rotate counter to the rotation of the bit-head while the cylindrical longitudinal cutters by theprepon- 4 derance of thrust ,at the inner portion of the bottom tend to rotate with the bit-head. Thus there results a variety of complemental chipping cuts over the surfaces of the new bore hole.

In accordance with the patent statutes, I have described what I now regard as the preferred embodiment of this invention, and explained the principles thereof but within the terms of the appended claims-various modifications and adaptations of this invention may now become apparent to those skilled in the art.

What is claimed is;

1. A roller bit for earth drilling, comprising a head having in combination a cross-roller cutter mounted therein with bottom-cutting teeth as a whole inclined upwardly and inwardly and extending substantially to the axis of the head, and

a roller-cutter mounted therein for rotation about an axis longitudinal of the bit and having bottom-cutting teeth adapted to effect a leading cut into the upwardly and inwardly inclined bottom formation left below the cut of the said up.- wardly inclined cross-roller teeth.

2. A roller bit for earth drilling, comprising a head having in combination a cross-roller cutter mounted therein with bottom-cutting teeth as a whole inclined upwardly and inwardly and extending substantially to the axis of the head, and a roller-cutter mounted therein having bottomcutting teeth adapted to effect a leading cut into the upwardly and inwardly inclined bottom formation left below the cut of the said upwardly inclined cross-roller teeth.

cutting teeth adapted to efiect a leading cut into the upwardly and inwardly inclined bottom formation left below the cut of the said upwardly inclined cross-roller teeth.

4. A roller bit for earth drilling, comprising a head having in combination. a conoidal'crossroller mounted therein with bottom-cutting teeth as a whole inclined upwardly and inwardly and adapted to effect a peripheral cut and to extend therefrom substantially to the axis of the head, and a cylindrical roller-cutter mounted therein with its axis longitudinal of the bit and with its upper end forwardly inclined substantially 20 in the direction of rotation of the drill and having bottom-cutting teeth adapted to effect a leading cut into the upwardly and inwardly inclined bottom formation left below the cut of the said upwardly inclined cross-roller teeth.

5. A roller bit for earth drilling, comprising a head having in combination a conoidal crossroller cutter mounted therein with bottom-cutting teeth as a whole inclined upwardly and inwardly and having a base containing wall-cutting teeth making an acute angle with the said bottom-cutting teeth, and a cylindrical roller-cutter mounted therein with its axis longitudinal of the bit and its upper end forwardly inclined in the direction of rotation of the drill, the cylindrical roller having bottom-cutting teeth adapted to eflect a leading cut into the upwardly and inwardly inclined bottom formation left below the cut of the said conoidal cross-roller bottom-cutter, and having longitudinal teeth adapted to ream the side wall above the area contacted by. the side-cutting teeth of the conoidal crossroller.

6. A roller bit for earth drilling, comprising aosau'r roller cutter mounted therein with bottom-cut ting teeth as a whole inclined upwardly and inwardly and adapted to effect a peripheral cut and to extend therefrom substantially to the axis of the head and with'a base containing side-wall to effect a leading cut into the upwardly and inwardly inclined bottom formation left below the cut of the said conoidal cross-roller bottom-cut- 'ter, and having longitudinal teeth adapted to ream the side wall above the area contacted by the side-cutting teeth of the conoidal crossroller.

7. A ,roller bit for earth drilling comprising a head having in combination a conoidal crossroller mounted therein with bottom-cutting teeth as a whole inclined upwardly and inwardly and extending from the periphery substantially to the axis of the head, and a cylindrical rollercutter mounted therein with its axis longitudinal roller mounted therein, with bottom-cutting teeth as a whole inclined upwardly and inwardly and extending from the periphery substantially to the axis of the head, and a cylindrical roller-cutter mounted therein with its axis longitudinal of the bit and from top to bottom rearwardly inclined in the direction of rotation of the bit, and having bottom-cutting teeth adapted to effect aleading cut into the upwardly and inwardly inclined bottom formation left below the cut of the said conoidal cross-roller cutter, the bottomcutters of the conoidal cross-rollers at the outer peripheral edge of their out being adapted to effect a leading out below the corresponding outer edge of the cylindrical longitudinal roller-cutters.

9. A roller bit for earth drilling, comprising a head having a conoidal cross-roller cutter mounted therein with bottom cutting teeth as a whole inclined upwardly and inwardly and with a base extended outwardly to clear the drill head, said base containing side wall-cutting teeth intersecting said bottom-cutting teeth at an acute angle to .form a wedge-like'peripheral cutting element adapted to facilitate penetration of a deflected bore wall and a roller cutter mounted in the head to effect a leading cut in the bottom formation above and inwardly of the peripheral cut of said acute-angled cutters.

10. A roller bit for earth drilling, comprising a head having in combination a conoidal crossroller cutter mounted therein with bottom-cutting teeth as a whole inclined upwardly and inwardly and extending substantially to the axis of the head-and with a base extended outwardly to clear the drill head, said base containing side wall-cutting teeth intersecting said bottom-cutting teeth at an acute angle to form a wedgelike peripheral cutting element adapted to faeili tate-penetration of a deflected bore wall and disposed to effect a leadingcut into the side of a deflected bore wall, the bithad having therein also a roller-cutter mounted for rotation about an axis generally longitudinal of the bit and containing bottom-cutting elements adapted to effeet a leading cut into the upwardly and inwardly inclined bottom formation left below the cut of the said conoidal cross-roller cutter.

CHARLES A. DEAN.

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