US 2953354 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
E. B; wlLLjAMs, JR 2,953,354
DRILL BIT 2 Sheets-Sheet i Sept-20, 1960 Filed May 15, 1958 Sept. 20, 1960 E. las.l WILLIAMS, JR 2,953,354
DRILL BIT Filed may 15, 195e 2 sheets-sheet 2 ATTORNEY DRILL BIT s claims. (c1. zss'gts'nv This invention relates to drill bits for drilling bore holes into earth formations, and particularly to drill bits of the type having cutting elements composed of diamonds and similar materials for cutting roc'k, chert, and other hard formations encountered in the drilling of such bore holes.
Drill bits of this type usually comprise an end cutting face for making hole Iand a circumferential cutting face for maintaining the bore thereof, consequently the cutting elements lare apt to be damaged when running the drilling string into and out of the bore hole, as when changing drill bits. Also, it may be desirable to continue drilling of a bore hole with a larger diameter bit and the clearance may not be suflicient to run the bit without endangering the cutting elements, or, in fact, the bit to make the larger hole may be too large to enter the bore hole that has been previously drilled. IIt may also be desirable to ream a lower portion of a bore hole to a larger size, in which case it becomes necessary to conrtinue the drilling with a larger'size bit that can be lowere through the existing bore hole.
It is, therefore, a principal object of the present invention to provide a bit of the diamond type that maybe safely run through a bore hole without dam-age to the cutting elements, and which may be run through holes of smaller diameter, as when continuing drilling toaV greater depth or to ream portions of the original hole..
vOther objects of the invention are to provide a drill bit with a cutting face oifset outwardly from the axisofrotation, a greater distance than the lcorresponding'face at the opposite side of the bit, so that the overall diameter will permit lowering of the bitthrough a bore hole of smaller diameter than the bore hole to be produced by thel cutting face of the bit; to provide a drill bit with ample watercourses in the cutting faces to assure sufficient ilow of drilling fluid to protect the cutting elements from overheating and to assure removal of the cuttings; and to provide for maintenance of such distribution of the drillf ing fluid in balance with the flow of drilling fluid upwardly of the side of the bit that is opposed to the cutting face.
4In accomplishing these and other objects of the invention as hereinafter pointed out, I have provided improved structure, `the preferred form of which is .illustratedA in the accompanying drawings, wherein:
Fig l is a perspective View of a drill bit embodying the features of the present invention as it appears when attached to the lower end of a drill pipe and lowered through a bore hole to a drilling position. v i
Fig. 2 is a horizontal cross section on 'the line 2-2 of Fig. 1, particularly illustrating clearance at sides of the drill bit.
Fig. 3 is an enlarged fragmentary cross section to better illustrate the clearance of the bit across the largest diame- -ter thereof with respect to the walls of the bore hole vthrough which the bit is lowered. 1 Fig. 4 is van enlarged vert-icaisection through the bit,
nited States Patent O 2,953,354 Patented Sept. 20, 1960 ice -1 showing the bit in drilling position at the bottom of the bore hole.
Fig. 5 is an end view of the bottom cutting face ofthe bit when in drilling position'. l Y' VReferring more in `detail to the drawings: i1 designates ya drill bit constructed in accordance with a i' the present" invention and particularlyadapted for drilling hard earth formations, such as chert and .the like. The bit 1 includes a body 2 formed Vof suitable material to with-` stand stress under operation, and has an exteriorly threadedk neck 3 adapted for attachment to a drill pipe `4. .The neck 3 is concentric with the axis 6 of the neck 3, andvforms with the body 2 Aan `annular shoulder 5, as best shown lin Fig. 4. One side 7 of the body 2 extends radially beyond the shoulder 5, while the opposite side 8 is generally in registry withthat side of the shoulder 5. The side 7 has an arcuate cutting face 9 formed on a -radiusv10 from the axis 6, and which constitutes the radius of the bore hole 11 to be drilled -by the bit. The opposite side of the body 2 has lan arcuate face 12 of less radius 10 and joins with terminal edges of the circumference of the drilling face 15 curves into the cutting or drilling face 9, as indicated at 16, and into a recess 17 in the axis of the bit on a rounding curve 18, as best shown -in Fig. 4. The recess 17 is preferably conical, as shown.
The drilling face 15 is preferably provided Wirth teeth 19 having Iadvance faces 20 and rearward facesr21 that slope downwardly from an Vupper edge of a face 20 to the lower edge of a face 20 of a preceding tooth. The teeth are generally spiral and provide generally spiral'channels or recesses 22 alternating with the ridges of the teeth and extending from the laxis of the face 15 outwardly to the periphery of the bit, where the channels 22 join with upwardly extending channels 23.4 The channels 22 and 23 provide passages for the movement of cuttings radially and Iupwardly of the body of the bit under ow of drilling iiuid to the upper end of the bore hole. The sloping faces 21 of the tooth portions of the bit may be provided with transverse grooves arranged spirally that form watercourses 24 to facilitate ilow of water and cuttings under the forward edges of the teeth to the channels 22.
The teeth are provided adjacent their forward edges with cutting elements 25, which may be commercial diamonds, borts, or other material of suiiicient hardness to cut the material being drilled. Y The cutting elements extend upwardly along the arcuate drilling face 9 of the bit to provide the cuts necessary for maintaining the gauge of the hole. The opposite face 12 of the body of the bit 2, since it is not depended upon for cutting, is provided only with upwardly extending watercourses 26 corresponding with the watercourses in the drilling face 9 of the bit.
The neck 3 and `upper body portion of the vbit basa bore 27 substantially conforming to the inner bore of the drill pipe to supply drilling fluid to a port 28 that is offset from the axis of the bit and located within the kbody portion 2, as best shown in Fig. 4. The bore terminates in the bottom face of the bit in an outwardly and upwardly extending channel 29, as best shown in Figs. 4 and 5, to provide an upward jet of drilling fluid. lThe port 28 also supplies drilling fluid across the bottom lcut'- ting face of the bit through watercourses 30, 31 and'32 that extend outwardly from the port 28, as shown in Fig. 5. The watercourses 30 and 31 terminate in diverging channels 33-34 and 35-36 to distribute drilling fluid in quantity to maintain the cutting elements infcoolcondition and to supply the drilling uid necessaryV for carrying the cuttings. to the top of the b'ore hole. Theport also communicates directly with the conical recess to supply drilling Huid to all of the channels or recesses that are formed between the teeth ofthe bit. The channels and watercourses are preferably designed to have a combined capacity relativelyto'the space provided betweenV the side 8v of'the bit andthe wallof'the bore hole, so as toassure adequate How of waterover the cutting faces; t
It is obviousgthatgtheside drilling face 9 curves on the common radius about the axis of rotation 6 and terminates at sides thereof in a chordal plane offset from the axis 6 onV the side of thel curved drilling face 9 and that the body portion of the bit has a plain opposite face 12 curving about the axis 6 on a shorter radius and which joins with the sides 13 and 14 of the curved drilling face to cooperate with the wall of the bore hole in leaving an arcuate space coextensive with said plain facey and whereby a bottom portion of the bore hole is progressively uncovered across lsaid plain face from one side ofthe curved drilling face to the other incidental to rotation of thebit. It is also obvious'that the arcuate space and said uncovered bottom portion of the bore hole provide a common uninterrupted discharge for the cuttings from all of the generally radial recesses on the side of the chordalY plane opposite the curved drilling face, andV that the supply of drilling uid from the downow passageway or port 28 supplies drilling fluid to all of the recesses fory washing the cuttings from said recesses and carrying the cuttings upwardly of the drill bit under the high volume ow through the arcuate space by the freedom of the flow from under the drill bit `and into the arcuate space.
VIn using the drill, constructed as described, it is `attached to the drill pipe 4 and lowered through the bo-re hole 11. When loweringthe drilling string through the bore hole, the drill pipeis olf center with respect to the bore hole, as indicated by the center lines in Figs. l and 2. In this position, all sides o the bit will clear the walls of the bore hole. When the drill bit reaches the bottom of the bore hole, with the end drilling face resting thereon and with the drilling fluid being circulated downwardly through the drill pipe, bore 27, and port 28, for upward flow through the borehole 11, the drill pipe is rotated so that the arcuate cuttingv face 9 will enlarge the diameter of the bore` holeV while the end drilling face penetrates the formation. During rotation, the conical portion ofthe cutting face cuts the pilot core to facilitate centering of thebit.
During the cutting operation, the drilling uid is dischargedifromlv the -port'23 through the channels 30 and 31 and branches 33-34 and 35e-36 thereof for flow throughV the channels 22 and grooves 24 to keep the cuttingV elements cool and to wash the cuttings from under the bit and upwardly through the channels 23 to the top of the borehole. Simultaneously, a jet of drilling uid is discharged throughV the channel 29 and upwardly at that sidevof the drill bit to'induce upward ow of the drilling fluid and cuttings carried therewith. The deepened bore hole made by the bitis of a radius corresponding to the radius of the cutting face 9 and results in a larger bore hole thanthe borehole immediately -above the place Where Vthe drilling started.
When it becomes necessary to remove the drill bit, the drilling'string is lifted inthe bore hole,tand when the bit reaches the upper portion of the hole, the bit shifts the drill pipe out of center position, whereupon the bit isV readily removed Without damage to the cutting elements.V `Frornthe foregoing, it isobvious that I have provided a drill bit of the diamond type which may be lowered througha bore hole and operated todeepen and/or enlarge the bore hole.
What I claim and desire'to secure by Letters Patent 1. A rotary drill bit having a body portion provided with a drilling face curving-on a common radius about an axis of rotation and terminating at sides thereof in a chordal plane offset from said axis of rotation on the side of.. said curved drilling face, cutting'elernents car ried in said'curvedl drilling face for maintaining gauge of; a bore hole having the radius of said curved drilling face when the bit is in use, said body portion having a plain oppositefface curving 'about the axis offrotation on a shorter radius and joining with saidsides of the curved drilling face to cooperate with the Wall of the bore hole in leaving an arcuate space coextensive with said plain face and whereby a bottom portion of the bore hole is progressively uncovered across said plain face from one side of the curved'drillingl face to the other incidental to rotation of said bit, said body portion having an end. drillingV face providedY With p generally radial'alternating ridges and recesses extending from said axis of rotation,
' cutting elements in said ridges and said recesses providing wardly of the drill bit under the high volume flow through said arcuate space by freedom of the flow from underthe drill bit and into said space.
2. A rotary drill bit as described in claim l wherein the plain face of the drill bit has a vertical channel directly connected with the downow passageway for providing an upwardly directed jet.
3. A rotary drill bit having a body portion provided with a drilling face curving on a common radius about an axis of rotation and terminating at sides thereof in a chordal piane offset from said axis of rotation' on the side of said curved drilling face, cutting elements carried in said curved drilling face for maintaining gauge of a bore hole having the radius of said curved drilling face when the bit is lin use, said body portion having a plain opposite face curving about the axis of rotation on a shorter radius and joining with said sides of the curved drilling face to cooperate with the wall of the bore hole in leaving an I'arcuate space coextensive with said plain face and whereby a bottom portion of the bore hole is progressively uncovered across said plain face from one side of the curved drill face to the other incidental to rotation of said bit, said body portion having an end drilling face provided with generally radial alternating ridges andV recesses extending from said axis of rotation, cutting elements in said ridges and said recesses providing relief for the cuttings produced by the cuitting elements, said arcuate space and said uncovered bot'- tom portion of the bore hole providing a common uninterrupted discharge for the cuttings from all of said recesses on the side of the chordal plane opposite said curved drilling face, said curved drilling face having vertical channels connected with Ithe `recesses on that side of the chordal plane, said body portion of the drill bit having a downow passageway opening through'said end face for supplying drilling fluid to said recesses for washing the cuttings from said recesses and carrying the cuttings upwardly of the drill bit under the high volume flow through saidarcuate space by freedom of the flow from under the drill bit and into said space, and said end drilling vface having channels connectingrsaid downtlow passage and extending across said ridges to certain 5 of the vertical channels to assure a proportional flow of drilling uid to the curved drilling face.
4. A rotary drill bit as described in claim 3 wherein the plain face of the drill bit has 'a vertical channel directly connected with the downow passageway for providing an upwardly directed jet.
5. A rotary drill bit having a body portion provided with a drilling face curving on a common radius about an axis of rotation and terminating at sides thereof in a chordal plane offset from said axis of rotation on the side of said curved drilling lface, cutting elements carried in said curved drilling face for maintaining gauge of a bore hole having the radius of said curved drilling face when the -bit is in use, said body portion having a plain opposite face curving -about the axis of rotation on a shorter radius and joining with said sides of the curved drilling face to cooperate with the wall of the bore hole in leaving an arcuate space coextensive with said plain face and whereby a bottom portion of the bore hole is progressively uncovered lacross said plain face from one side of the curved drilling face to the other incidental to rotation of said bit, said body portion hav ing an end drilling face, cutting elements in said end drilling face, said end drilling face having Vintercom-ses leading to said arcuate space at said uncovered bottom portion of the bore hole for discharge upwardly through said arcuate space, and said body portion of the drill bit having a downilow passageway opening through said end drilling face for supplying drilling uid to said watercourses for washing the cuttings from said cutting elements in the end drilling face and carrying the cuttings upwardly of the drill bit under a high Volume ow through said arcuate space by freedom of the flow from under the drill bi-t into said space.
References Cited in the iile of this patent UNITED STATES PATENTS 443,072 Chapman Dec. 16, 1890 1,256,968 Young Feb. 19, 1918 1,463,566 Akins July 31, 19213 1,587,266 Zublin June 1, 1926 2,425,132 Stokes Aug. 5, 1947 2,614,809 Zublin Oct. 21, 1952 2,802,642 Feucht Aug. 13, 1957