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Publication numberUS2044549 A
Publication typeGrant
Publication dateJun 16, 1936
Filing dateAug 20, 1931
Priority dateAug 20, 1931
Publication numberUS 2044549 A, US 2044549A, US-A-2044549, US2044549 A, US2044549A
InventorsScott Floyd L
Original AssigneeHughes Tool Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Three-cutter bit
US 2044549 A
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Description  (OCR text may contain errors)

June 16, 1936.

F. L. SCOTT THREE- CUTTER BIT Filed Aug. 20, 1931 I I I I I I I 2 Sheets-Sheet 1 FIG. 2



F. 1.. SCOTT 2,044,549

THREE-CUTTER BIT Filed Aug. 20, 1931 2 Sheets-Sheet 2 FLOYD L-. SCOTT INVENTOR BYdQW-WM ATTORNEY Patented June 16, 1936 PATENT OFFICE THREE-CUTTER BIT Floyd L. Scott, Houston, Tex., assignor to Hughes Tool Company, Houston, Tex., a corporation of Texas Application August 20,


My invention relates to bits for use in deep well drilling.

The invention has particular application to bits of the so called roller type having thereon cutters adapted to roll upon the bottom of the hole and cut up and disintegrate the material.

It is an object of the invention to provide a drill bit in which the cutters are secured in posi tion in such a manner as to be easily disengaged from the head or assembled in position thereon.

I also desire to so mount the cutters on the head as to obtain a particularly eflicient cutting action of the said cutters upon the bottom of the hole.

' I also desire to provide an assembly of cutters which will be balanced so as to roll smoothly on the bottom of the hole and rapidly disintegrate the material.

My invention resides particularly in the con.-. struction of the head and a holder for the cutters which may be assembled in the head firmly and securely with a minimum of manipulation.

In the drawings herewith, Fig. 1 is a side view partly in vertical section showing the holder which I employ for the cutters. Fig. 2 is a side elevation of said holder drawn at right angles to the view shown in Fig. 1. Fig. 3 is a central vertical section through the assembled drill with the cutters in position.

In constructing my drill, I provide a head I. which is approximately cylindrical, having an upper threaded shank 2 for engagement with the drill collar. The lower end of the head is recessed to provide two downwardly extending legs 3 which have notches or recesses 4 at their lower ends to receive the shafts 5 and 6 for the outer cutters. The bit head is provided with a relatively large axial channel 1 extending downwardly through the shank to connect with a somewhat larger recess 8 which connects with the main recess between the side legs 3.

Within the recess in the head of the drill I mount a holder shown in Figs. 1 and 2. It has an upper head 9 to fit within the recess 8, this head being cylindrical and provided with aninner threaded socket l0. Below the head the holder is connected by means of a neck H with two diverging arms l2 having thereon outwardly and upwardly extending shafts 5 and 6 for the cutters. The lower end is forked to provide a cutter recess l3, and the ends of the forked portion are formed with a recess M at one side and an opening l5 at the other to receive the cutter shaft I 6.

The cutter holder has on the two sides at right 1931, Serial No. 558,295

angles to the shafts 5 and 6 outwardly extending reamer blades lB--A. These blades extend outwardly to the wall of the hole and act as scraping cutters to maintain the gage of the hole. Their upper edges extend upwardly along the side of the head 9 of the holder, and the lower edge of each leg extends to a point about even with the shafts 5 and 6, the lower end being beveled forwardly at I! in the direction of the rotation of the bit.

When the tool is assembled, the head 9 of the holder is fitted within the recess 8 and a packing ring 3 is fitted within an annular recess IS in the outer wall of the chamber 8 to engage the outer surface of the head 9, and preserve a fluid seal at that point. A locking post 20, which is of tubular construction, is inserted downwardly through the opening I in the shank of the bit, and its threaded lower end 21 is engaged within the socket ID of vthe holder. post 20 is enlarged and provided with a lower shoulder 22'which engages with the upper end of the shank so as to draw the cutter holder upwardly in the head and hold it rigidly therein.

- When the holder is thus mounted in the head the flushing fluid may pass downwardly through the channel 23 in the post 20, and will find an outlet through passages 24, 25, 26, and 21 to the pockets in which the cutters are mounted.

The cutters are shown as three in numberl There are two'outer cutters 28 and 29 which cut the gage of the hole and remove the material from the bottom of the hole adjacent the wall thereof. There is also a central cutter 30 mounted on the shaft l6 and formed to cut the material from the center of the hole inside the paths cut by the two outer cutters.

The cutter 28 is mounted on the upwardly inclined shaft 5 and is provided with roller bearings 3|. The outer periphery is toothed and tapered outwardly so that when extended the surface would converge to an apex outside the Wall of the hole. Each of the outer cutters has an outer washer 32 providing a thrust surface for the outer end of the cutter and holding the roller hearings in position.

The cutter 29 is also provided with bearings 33 and washer 34. Its outer surface is toothed and tapered to converge beyond the wall of the hole. It is, however, narrower in width than is the cutter 28.

The cutter. is also provided with roller bearings. It is cylindrical at one end and tapered at 35 toward the axis of the drill. This cutter removes the material from the center of the hole,

The upper end of the H steady the action of the outer cutters.

and its shaft I6 is offset downwardly in advance of the two shafts 5 and 6. All of the cutter shafts are approximately in the same vertical plane.

When the holder with the cutters mounted thereon is clamped in position in the head by means of the post 20, the upper ends of the two reamer blades l8-A will be received within notches 36 in 'the head of the drill. This will serve to support the reamer blades to some extent and will deliver a driving torque uponthe blades during the rotation of the drill. The shape and position of the two outer cutters 28 and 29 enable the cutters to have a particularly effective action in cutting the formation. They do not have a true rolling'motion, but will have a slipping or scraping action on the well bottom in addition to the rolling, chisel action of the teeth,

and will thus remove thematerial more rapidly. The inner cutter 30 extends slightly in advance of the two side cutters, and serves to center and noted that the larger cutter 28 at the side is arranged adjacent the small end of the central cutter 30. I thereby get a more balanced action of the three cutters which tends to prevent vibration, and will enable a straight hole to be drilled.

The advantages of the construction lie in the simple manner in which the cutters may be mounted in the head of the drill with a. minimum of difficulty, and in the particularly effective action of the cutters so formed and mounted whereby I am enabled to drill a formation with comparatively high speed.

What I claim as new is:

1. A well drill including a head having an axial opening therein, oppositely disposed supporting legs on said head, a holder adapted to fit between said legs, opposite upwardly inclined cutter shafts on said holder to engage in recesses in saidlegs, a shank on said holder, a hollow post extending downwardly through said head and screwed within said shank, a central cutter shaft on said holder and rolling cutters on said shafts, the axes of said shafts being all in' the same vertical plane.

2. A well drill as set out in claim 1 and in which said holder is formed with laterally extending reamer blades thereon.

3. A well drill including a head, a. holder fltting within a recess in said head, means to retain said holder in said head, cuttershafts on said holder including two outwardly and upward- 1y projecting shafts the ends of which engage within said head,and an inner inclined shaft, the axes of said shafts lying in the same vertical plane, and rolling cutters on said shafts.

4. A well drill including a heads. holder fltting within a recess in said head, means to retain said holder in said head, cutter shafts on said Itwill be holder including two outwardly and upwardly projecting shafts the ends of which engage within said head, and an inner inclined shaft, the axes of said shafts lying in the same vertical plane, and rolling cutters on said shafts, the cutters on said outer shafts being tapered outwardly to converge outside the wall of the hole.

5. A well drill including a head, a set of three having its outer end inclined upwardly and outwardly, cutters on the two outermost of said shafts, the peripheries of each cutter being tapered to converge at a point outside the wall of the hole being drilled, and an intermediate cutter having its inner end tapered downwardly to extend across the longitudinal axis of the head, said outer and intermediate cutters together acting to cut the full bottom of the hole.

7. An earth boring drill having a bit head with a. recess in its lower end and a socket above the recess with a slot extending through the wall of the socket, a carrier member having a portion to fit the recess' and portions to fit the socketand slot respectively and roller cutters mounted in the carrier with their axes in substantially the same vertical plane and arranged to cut the entire area at the bottom of the hole.-

8. A roller cutter carrier member for an earth boring, drill adapted to fit into the lower end of the'bit head of said drill, said member having a cutter receiving recess and bearing openings for a cutter spindle communicating with said recess, the axis of said bearing'openings being inclined relatively to the vertical axis of said carrier member, and in a plane radial to said vertical axis, said carrier member having exterior lugs to fit into recesses in the bit head and a fluid passageway in said member, substantially as described. a

9. In combination, a bit head having a cutter receiving recess therein, spindle and supporting means extending from end to end of the said recess in the head, interfitting lug and recessed portions between the supporting means and the side of the head, disposed laterally of the supporting means and above the cutters, means forsecuring the lug within the recessed portion, and roller cutters on the spindle means.

FLOYD L. sco'rr.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4193464 *May 8, 1978Mar 18, 1980Smith International, Inc.Replaceable shirttail
US7320375Jul 19, 2005Jan 22, 2008Smith International, Inc.Split cone bit
U.S. Classification175/362, 175/376, 175/340, 175/363
International ClassificationE21B10/10, E21B10/08
Cooperative ClassificationE21B10/10
European ClassificationE21B10/10