US 3760894 A
A replaceable blade drilling bit wherein the blades have shoulders engageable with the body to absorb longitudinal thrust on the cutting edge of the blades from the cutting edge axially of the body. The blades are anchored in place on the body at the ends of the blades opposite the cutting edges by bolts or other securing means. The body may be made for three, four or five blades. Also, retaining means is provided on the blades engageable in grooves in the body for absorbing torsion or torque circumferentially of the axis of the body as the bit is used.
Description (OCR text may contain errors)
United States Patent 1191 Pitifer 1 Sept. 25, 1973 REPLACEABLE BLADE DRILLING BITS  Filed: Nov. 10, 1971 [211 App]. No.: 197,208
3,326,308 6/1967 White 175/413 Primary Examiner-Marvin A. Champion Assistant Examiner-Richard E. Favreau AttorneyE. Hastings Ackley  ABSTRACT A replaceable blade drilling bit wherein the blades have shoulders engageable with the body to absorb longitudinal thrust on the cutting edge of the blades from the cutting edge axially of the body. The blades are anchored in place on the body at the ends of the blades opposite the cutting edges by bolts or other securing means. The body may be made for three, four or five blades. Also, retaining means is provided on the blades engageable in grooves in the body for absorbing torsion or torque circumferentially of the axis of the body as the bit is used.
5 Claims, 10 Drawing Figures 52 US. Cl. 175/413, 175/419  Int. Cl. E2lc 13/00 58 Field of Search 175/412, 413
 References Cited UNITED STATES PATENTS 1,429,041 9/1922 Legate 175/412 X 2,978,049 4/1961 Skidmore 175/413 X 1,641,113 8/1927 Brunt 175/413 X 2,803,435 8/1957 Kammerer 175/413 2,815,933 12/1957 Dionisotti 175/413 X 2,857,140 10/1958 Johnson 175/413 X PAIENIEDSEPZSW 3.760.894
SIEU 1 BF 2 INVENTOR ,-26 Michael J. Piii fer ATTORNEY REPLACEABLE BLADE DRILLING BITS SUBJECT MATTER AND OBJECTS OF THE INVENTION This invention relates to replaceable blade drilling bits having a plurality of removable and replaceable cutter blades.
One object of the invention is to provide a new and improved replaceable blade drilling bit.
Another object of the invention is to provide a new and improved form of rotary drilling bit having interchangeable removable and replaceable cutter blades which are anchored securely against the cutting thrust to the body of the bit and wherein the support for the blades on the body is in opposition to the thrust of the body against the blades during the cutting action.
It is a further object of the invention to provide a drilling bit of the character set forth in which the blades are readily removable and replaceable to permit speedy and efflcient replacement of the cutter blades without requiring disassembly of the other parts of the bits or disassembling the bit or disconnecting the bit from the drill string.
Stil another object is to provide a rotary type drilling bit assembly of the character set forth equipped with removable cutter blades which may be readily adapted to drilling holes of different diameters and wherein the means for receiving and supporting the cutter blades is quickly releasable.
A particular object of the invention is to provide a drilling bit of the character described wherein the cutting blades are securely anchored in the body against twisting torque, against the effects of longitudinalforce applied to the cutting edges and the circumferential force applied to the longitudinal cutting edges or sides of the blades in use.
I Still another object of the invention is to provide a bit of the character described wherein the blades are readily interchangeable between bodies having three, four or five grooves for receiving the blades, to provide for economical manufacture and ready exchange of bits between bodies of different types.
Still another object of the invention is to provide improved supporting means-for the blades on the body.
Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention and reference to the accompanying drawings thereof, wherein:
FIG. 1 is a side elevation of a drilling bit constructed in accordance with the invention and showing a four blade bit;
' FIG. 2 is a cutting end view of the bit of FIG. 1;
FIG. 3 is a fragmentary sectional view taken on the line 3--3 of FIG. 1 showing the support for the blade on the body;
FIG. 4 is an exploded view of the body and the blades of the drilling bit of FIGS. 1 and 2;
FIG. 5 is an enlarged fragmentary view of one of the blade supporting grooves of the body of the bit;
FIG. 6 is an enlarged fragmentary view of the upper end of a blade showing the means for securing the blade in place on the body;
FIG. 7 is a fragmentary horizontal sectional view taken on the line 77 of FIG. 1, further showing th support for the blade on the body; 1
FIG. 8 is a view similar to FIG. 7, showinga modified form of support for th blade in the body;
FIG. 9 is a view similar to FIGS. 7 and 8, showing a further modified form of the mounting for the blade on the body; and,
FIG. 10 is a cutting end view of a further modified form of drilling bit having five blades mounted on the body.
In the drawings, particularly FIGS. 1 and 4, the drilling bit is designated generally by the numeral 10, and includes a body member 11 having a bore 12 therethrough and connecting means such as the externally threaded pin 13 at one end for connecting the body to a drill pipe. The body has a plurality of uniformly spaced blade receiving undercut grooves 15 formed in the substantially cylindrical portion 14 thereof below the pin, and the slots may number two, three, four or five, as desired, for receiving and supporting replaceable cutter blades 20. As clearly shown in FIGS. 3 and 5, the slots 15 each have lateral undercuts l6 and 17 on the opposite sides thereof to provide grooves for receiving laterally projecting flanges 18 blades 20 carried by the body. The cutter blades are slid upwardly in the slots until the curved upper end 21b ef the body 21 engages the concave curved-stop shoulder 22 at the upper end of the slot 15. When the upper end of the blade body engages the concave stop shoulder 22, a securing bolt 23 threaded through the upper end of the body is in position to be moved to project into a locking recess 24 formed in the upper end of the bottom 28 of the slot 15. When the locking screw 23 is made up right in the recess 24, it draws thelower end of the blade 20 upwardly toward the lower end of the body until a downwardly and inwardly beveled shoulder 26 at the upper end of a rib 29 projecting inwardly beyond the inner face 21a of the blade between the laterally projecting flanges 18 and 19 engages a complementary downwardly and inwardly sloping stop shoulder 27 formed on the bit body at the lowerend of the bottom 28 of the slot 15. The engagement of the beveled shoulder 26 with the beveled stop shoulder 27 limits upward movement of the blade with respect to the body, along with the engagement of the concave shoulder 22 in the slot by the rounded end 21b at the upper end of the blade, so that all longitudinal thrust during cutting operations is absorbed by the engagement of the end shoulder 21b with the concave stop shoulder 22 and the beveled shoulder 26 with the beveled stop shoulder 27 of the body. The inward projecting rib 29 having the stop shoulder 26 at its upper end extends from near the midportion of the body 21 downwardly to a point above thelower cutting edge 30 of the blade 20, and is undercut to provide a flow course 31 through which drilling mud may be circulated outwardly from the flow passage 12 of the body 10. The blade 20 projects further inwardly toward the center or axis of the body to provide an abutment shoulder 32 having a face 33a thereon which is disposed to engage a complementary face 33b on an adjacent blade to absorb lateral inward thrusts of the outer cutting edge 34 of the blade as the bit is used. The upper portion 35 of the outer edge of the blade is inclined upwardly and inwardly toward the flanges 18 and 19, so that portion of the blade will not engage the wall of the hole being drilled. An external longitudinal flow course 36 is formed on the rear side 37 of the blade outwardly of the rib 18 to facilitate flow of fluids upwardly through the well exteriorly of the blade. The lower end of the body 20 of the blade is thickened somewhat to provide more support for the hard cuttinginserts 39 at the lower end of the face 38 of the blade and lateral inserts 40 along the lower edge of the face of the blades, which do the cutting during the drilling operation.
External flow courses 41 are formed on the outer face of the lower cylindrical portion of the body 11 of the bit between the blades, and the body is formed with flattened surfaces 42 along the opening of the elongate longitudinal grooves 15 to further facilitate flow of fluids past the blades during use of the bit.
When the four blades are in position to be inserted into the grooves 15 in the body 11, as shown in FIG. 4, the laterally projecting flanges 18 and 19 are disposed to slide upwardly in the undercut slots 16 and 17, respectively. The locking bolts 23 are threaded outwardly to a non-projecting position, and when the blades are fully inserted upwardly into the slots 15, the bolts then are threaded inwardly into the locking recesses 24 in the bottom of the slots to lock the blades on the body.
As shown in FIGS. 1, 2, and 4, four blades are mounted on the bit body 1 1. As shown in FIG. 10, five blades are mounted on the body. It is believed obvious that only two blades may be mounted on the body shown in FIG. 2, being mounted diametrically opposite each other, if desired. Also, it is believed readily apparent that three blades may be mounted in the body in longitudinal slots 15 spaced uniformly around the periphery of the enlarged substantially cylindrical lower portion 14 of the body.
It is also clear that the projecting lateral edges 34 and 35 of the blades 20 may extend outwardly different distances from the lateral flanges 18 and 19 on the body 21 of the blade, so that the size of the hole drilled by the bit may be varied by changing the sets of blades on the body section 14 of the bit.
FIG. 7 shows a cross section through the lower portion of one of the blades 20 of FIGS. 1 through 6. However, the cross-section of the blade may be modified as shown in FIGS. 8 and 9 to provide rounded flanges 118 and 119 projecting laterally from the body 121 of the blade 120. These rounded flanges engage in rounded recesses or grooves 116 and 117 formed in the body on opposite sides of the elongate longitudinal slot 115 in cylindrical portion 114 of the body 111. Otherwise, the blades and body are identical to that first described.
A further modifi9, wherein the lateral retaining ribs 218 and 219 are substantially triangular in cross section and fit into substantially triangular undercut recesses 216 and 217 in the slot 215 of the lower body section 214. Otherwise the blades of FIGS. 8 and 9 are identical to the blades of FIGS. 1-7. Each of the blades has the inwardly projecting lateral support member 232having the abutment faces 33a and 33b which abut the corresponding portions of adjacent blades to support the outer cutting edges 34 against inward thrust toward the axis of the bit during operation.
It will readily be seen that the blades are adapted to be inserted into the longitudinal slots 15, 115, or 215 in the lower cylindrical portions of the drill bit and easily secured in place therein. It is readily apparent that one blade may be changed without the necessity of changing or otherwise handling the other blades. It is also apparent that the blades may be changed without requiring that the entire bit be disconnected from the drill pine.
It is further to be seen that the blades are adapted to fit in drill bit bodies 11 having slots 15 therein at uniformly dircumferentially spaced positions therearound; and, since theblades are identical, that the same blade will fit in any slot of a body having any number of identical slots therein. Thus, the blades may be used in bits having two, three, four or five slots in their body with equal satisfaction.
It will also be seen that the slots may have different shaped retaining members for supporting the blades against lateral inward thrust while being used, but that uniformly the convex upper end 21b of the body 21 of the blade 20 will engage the stop shoulder 22 at the upper end of the slot 15 and that the stop shoulder 26 projecting inwardly from the rib 29 on the rear of the body of the blade will engage the downwardly and inwardly inclined stop shoulder 27 on the body 11 to absorb upward longitudinal thrust as the blade is used for cutting.
It will further be seen that flow courses have been provided for drilling mud or water and the like which communicate with the central bore 12 of the body 11 of the bit and that such flow courses provide for ready circulation of drilling mud or water past the cutting edges of the bit for removing cuttings from the drilled hole.
It is further readily apparent that the blades may be quickly and easily replaced when necessary, the identical blades permitting economical fabrication of the blades reducing the cost thereof and providing for bits having a variety of numbers of blades and blade arrangements thereon. It will also be seen that the blades are tightly secured in place on the bit body, but may be quickly and easily replaced when damaged or worn without the necessity of removing all blades, or of disconnecting the bit from the drill pipe.
Also, it is believed readily apparent that the diameter of the hole to be drilled may be varied by varying the width of the blade to space the cutting edge 34 of the blade further outwardly from the flanges 18 and 19 of the body and hence space the cutting edge further outwardly from thecylindrical body section 14 of the bit, so that a larger hole may be drilled. Thus, blades may be interchanged to change the diameter of the hole being drilled, while using a common body.
The foregoing description of the invention is explanatory only, and changes in the details of the constructions illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.
What is claimed and desired to be secured by Letters Patent is:
1. A drill bit including: a bit body having connecting means at one end and a longitudinal flow course therethrough; said body having a substantially cylindrical enlarged lower body portion provided with a plurality of longitudinally extending recesses in its exterior surface opening from the lower end of said cylindrical portion upwardly of the body to a stop shoulder at the upper end of the recess; each of said recesses having a bottom and opposed undercut lateral portions and a locking recess at the upper end of the bottom of the recess and an inclined stop shoulder at its lower end; a detachable blade adapted to be removably mounted in each of said recesses of said bit body; each of said blades having opposed outwardly extending retaining flanges engageable in corresponding longitudinal undercut lateral portions at each side of the longitudinally extending recesses-in the bit body; each of said blades having means providing a downwardly and inwardly inclined stop shoulder on th inner surface of the blade disposed to engage said stop shoulder at the lower end of the recess of the bit body substantially simultaneously with the engagement of the upper end of the body with the stop shoulder at the upper end of the recess in the bit body; and locking means carried by the blade movable into the locking recess in the bottom of the recess of the bit body to lock the blade against downward movement out of the recess on the body.
2. A drill bit of the character set forth in claim 1 wherein each of said blades has inwardly projecting stop shoulders at its lower inner end engageable with complementary stop shoulders on adjacent blades to provide support against inward lateral displacement of the blades during use.
3. A drill bit including: a bit body having connecting means at one end and an enlarged substantially cylindrical body portion at its opposite end extending longitudinally from said connecting means and having a longitudinal fiow passage therethrough; a plurality of Iongitudinally extending blade receiving recess on the exterior surface of the enlarged cylindrical body portion extending from the opposite end thereof toward the connecting means; each blade receiving recess having a bottom and a laterally outwardly undercut retaining shoulder along each longitudinal side thereof; a first outwardly directed stop shoulder at the end of the recess nearest the connecting means and a second stop shoulder at the opposite end of said recess extending angularly toward the end of the cylindrical body portion opposite the connecting means and inwardly toward the longitudinal axis of the body; each of said blade receiving recesses having a locking recess in its bottom adjacent and spaced from the end of the recess nearest the connecting means on the body; a plurality of interchangeable substantially identical replaceable cutter blades on of each adapted to be removably mounted in one of each of the recesses of said bit body and secured therein independently of the other blades in the other recesses; each of said blades lateral retaining flanges of a shape fitting beneath the undercut shoulders along the sides of the blade receiving recesses and having longitudinally spaced stop shoulders engageable with the first and second stop shoulders on the body to limit movement of the blades in the recesses toward the connecting means of the body; releasable securing means on each blade adjacent and spaced from the end thereof nearest the outwardly directed shoulder at the end of the recess nearest theconnecting means on the body and movable into the locking recess in he bottom of the blade receiving recess to secure the blade in said recess with the stop shoulders on the blade engaged with the stop shoulders on the body, whereby said blades are each interchangeable with the blades in the other recesses, so that any one blade will fit in and be lockable in each of the recesses of the bit body; said securing means on said blades being retractable from the locking recesses in the body to permit said blades to be each separately removable from and replaceable in the blade receiving recess of thebit body in which it is disposed without disturbing the other blades in the other blade receiving recesses.
4. A drill bit of the character set forth in claim 3 wherein the releasable securing means comprises a lock bolt threaded through the blade at an angle with respect to the bottom of the groove and directed angularly inwardly toward the longitudinal axis of the body and divergent from said first stop shoulder on said body.
5. A drill bit of the character set forth in claim 3 wherein each of said blades has inwardly projecting stop shoulders at its lower inner end engageable with complementary stop shoulders on adjacent blades to support the lower cutting edge portion of the blades against inward lateral displacement of the bit body during use.
222 3 UNITED STTES PATENT OFFICE I CERTIFICATE OF CORRECTION Patent No. 3,760,894 Dated September 25-,- 1973 Inventor) Michaeli J. Pitifer.
It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
I Column 2 line 22, after "18" insert -.-and 19 from the inner faces 21a of the body 21 of the cutter --r v line 32 for "right" read "tight-- v line 53 fer "the1ow'er" read -the wer-1 Column 3, line 3, for "cuttinginserts" read "cutting inserts-- line 48, for "modifi9" read -mo di fication of the blades is shown in Figure 9, I line 55 for "232having" read "232 havi g-- line for "pine' read pipe-- line 42, for "thecylindrical" read "the cylindrical- Columnv5, line for 'recess'v' read --re cesses i' I line 40", for 'on" read- "one-.-
Column 6 line 3, after "'h1ades"' insert --having1 longitudinallj extending outwardly projecting-'- w TE m 'w n Q CERTIFICATE OF CORRECTION I f E ten: n0. 3.760.894 Invencofls) Michael J. Pi ti. f e; I H v I It is certified that error appears in the a bbve-i dentifled patent and that said Letters 'Patent are hereby corrected as shown below: i 3
@Column" 6, line 12, ;for "thecqnnecltin'g' readi theconnectingline 23, o-r- "thbit" read' -e-the bit Signed and sealed this 17th da a:[September 1-914.
McCOY M cijsso'w JR; I ":,QMARsi1ALL'-DANN Attesting Officer j v I I t s I Cbmissjioner of Paten