US2070001A

US2070001A - Rotary core bit

Info

Publication number: US2070001A
Application number: US9158A
Authority: US
Inventors: Leonard S Copelin
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-03-04
Filing date: 1935-03-04
Publication date: 1937-02-09
Anticipated expiration: 1954-02-09

Description

Feb. 9, 1937. L. s. coPELlN ROTARY CORE BIT Filed March 4, 1935 2 Sheets-Sheet l INVENTOR. L. 5. Cope/in ATTORNEY.

Feb. 9, 1937. L, 5. CQPELlN 2,070,001

ROTARY CORE BIT Filed March 4, 1935 2 Sheets-Sheet 2 IVENTOR. l 5. ope/fn mfg/oem ATTORNEY.

Patented Feb. 9, 1937 UNITED STATES FATENT OFFICE ROTARY CORE BIT Leonard S. Copelin, Los Angeles, Calif. Application March 4, 1935, Serial No. 9,158

7 Claims.

This invention relates generally to rotary drills such as are employed for earth-boring operations. More particularly it relates to the construction of cutting heads or bits for drills of the core-forming type.

It is an object of the invention to provide a drill bit which will afford efficient and reliable operation and which will not tend tobind itself within the hole being drilled.

It is a further object of the invention to provide a bit characterized by utmost simplicity of con struction and by the absence of conventional pilot teeth surrounding the core passage.

Further objects of the invention will appear from the following description in which the preferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings:

Fig. 1 is a side elevational view, in cross-section, showing a rotary core drill incorporating the present invention.

Fig. 2 is a side elevational view, showing the cutting head or bit incorporated in the drill of Fig. 1.

Fig. 3 is a view similar bit rotated through 90.

Fig. 4 is a cross-sectional detail taken along the line 4-4 of Fig. l.

Fig. 5 is a cross-sectional detail taken along the line 5--5 of Fig. 1.

Fig. 6 is a bottom plan view of the drill shown in Fig. 1.

The drill as illustrated in Fig. 1 consists generto Fig. 2, but with the ally of a drill body I0, having a cutting head or drill bit Il secured to the lower end of the same, as by means of a threaded connection I2. The outer core barrel I3 is secured to the upper end of the drill body. Within the outer barrel I3 there is an inner core'barrel or retainer I4, the lower end of which is secured to the drill body The cutting head is provided with a vertical opening I5 concentric with the axis of rotation, which permits a core to progress upwardly into the core retainer I4.

r cones, indicated at 2|, represents the regio-n of (Cl. Z55-72) demarcation between the different angles to which the surfaces I8 and I9 are beveled. At the lower end of the bit body there is a lip 22 surrounding the core opening I6, and this lip is substantially uninterrupted except for portions of the wing teeth, instead of being provided with pilot teeth as in conventional constructions.

It is desirable from the standpoint of simplicity to form the wing teeth integral with the body of the bit, although suitable detachable mountings can be provided if desired. The wing teeth Ia, may be duplicates, and are carried on opposite sides of the bit. Each of these teeth affords an advancing face 23 in a general plane inclined with respect to the vertical. Below the region oi' the surface area I9 and the lip 22, each wing tooth I8a provides a depending tooth portion 24. Thus each of the wing teeth lila is formed to afford lower substantially horizontal cutting edges 2B and 21, which are stepped to cut on areas of different diameters. In Fig. 1 these areas have been designated by numerals 28 and 29. The inner edges of tooth portions 24 extend slightly inwardly of the periphery of opening I6, in order to form a core 32 of proper diameter to pass upwardly into` the core retainer. The advancing face of each tooth portion 24 is shown as being a continuation of the general advancing face 23 for the corresponding wing tooth.

The wing teeth I8b differ in positioning and proportioning in order to aflord a desired reaming action. Each of these teeth has an advancing face 33, which lies generally in a vertical plane. Lower depending tooth portions 34 are provided, corresponding to the tooth portions 24 for wing teeth lita. Lower stepped cutting edges 35 and 3'I are provided, which likewise act on areas of the formation at different diameters. Outer vertical rearning edges 38 are provided, which extend to radii beyond the corresponding outer edges 39 for the teeth I8a.

With respect to the positioning of the

lower cutting edges

26 and 36, all of these edges preferably lie in a common plane normal to the axis of rotation. However, the lower edges 31 lie generally in a plane normal to the axis of rotation, which is at a slightly higher elevation than a corresponding plane coincident with the cutting edges 21 for wing teeth I8a. In general, the advancing faces of all the wing teeth are preferably at an angle, with respect to radii coincident to the same and normal to the axes of rotation. In other words, the advancing faces are disposed non-radially, so as to tend to urge cuttings outwardly as the bit rotates.` ISIS` In combination with the features described above, provision is made for delivering lubricating mud tothe bit, in sucha manner as to insure propercarrying away of cuttings without clogging. Thus the body of the bit is provided with substantially vertical passages 4| for lubricating mud, there being one passage for each of the main teeth, It is desirable to have these passages fiattened incross-section, as illustrated `in Fig.V 6, in order to avoid undue erosion of metal by the scouring action of sand. In this connection it may be explained that with acircular passage for .the V'outer and lower areas of Vthese advancing faces, asis evidenced in Fig. l.. Likewise, the discharge is immediately above the junction 2| between the surface areas I8 and I9. YWith respect to the formationbeing acted upon, the 'disdrill bodyV 0.

charge ends ofthe ports 4| are likewise substantially directly above the shoulder 43 formed at the junction between the areas 28`and 29. As

v Y. will be presently explained, such an arrangement Yfor the portsr4| is conducive to eiicient action of the rotary mud in carrying preventing clogging. Y Y

As representative Vof a suitable expedient for away cuttings and delivering rotary mud to the ports 4|,Vthe upperend ofthe bit body is. shown `provided with an of the ports 4| and which in turn communicates with a greaternumberof ports 46 formed in the tice, lubricating mud is circulated downwardlyV throughthe space-4`| between the inner and outer core barrels, to be'delivered through passages 46,

and from thence through the ports 4|.

t is generally desirable to incorporate suitable core catching means in conjunction with the drillV bit. Such a core catcher has been indicated generally at 48.V

Operation of the invention described above can now be explained as follows:-During a drilling operation, the lower tooth portions 24 and 34cut on the area 28 of the formation, and therefore define the core 32 `in'addition to performing a Y substantial part of the drilling operation. Cut'-VV ting edges 2'1k of the teethV |8a (which have theV inclined advancing faces 23) cut upon the 'larger diameter area 2...- Wing teeth` |8b, and particularly the'vertical edges 38,V perform a reaming` operation upon the side walls of the hole, and,

Y because of the vertical positioning of the same as distinguished from the inclination of the corresponding edges39 of teeth |8a, the hole is formed c5y cork-screw effect such as is common in bits of the withsmooth side surfaces, without a so-called prior art. vBecause of the Yabsence ofthe usual pilot teeth on the lip 22, more bearing pressure is madeY possible upon the lower cutting edges, with the result that an increase inthe rateV of drilling-is made possible.Y Likewise elimination of pilot teeth greatlyreduces frictional heat on the core, and thereforethe core `does not tend to V' ,..dry'with` consequent stickingy tothe throat orY plugging of the bit. Asl indicated in a vgeneral annular recess 44, which communicates with allV way by the arrows in Fig. 1, lubricating mud dis- Y charged from the ports 4| is distributed over the advancing facesof the wing teeth, with an affective flow of a substantial part of the mud down into the regions in advance of the

lower tooth portions

24 and 26. carried away from all of the active cutting and reaming edges,` to facilitate a rapid cutting rate and to prevent clogging or balling up of material about the teeth. Due to the efficient and-effectivek manner inV which lubricating mud is circulated to the bit, and

due also to the efficient reaming action afforded by the vertical Yedges38, the drill is not subject to jamming in the hole and can always be raised without diiculty.

1t is to be understood that the various cutting Vand reaming edges can be reinforced by suitable hard metalY alloy, in order to afford greater resistance to wear. Such practice, however, is common in the manufacture andrepair Vof rotary bits, and need not be described in detail.

'l claim: Y Y 1.5In a rotary earth-boring drill, a cutting head comprising a body providedwith at least four circumferentially spaced teeth, two of the teeth` Thus, cuttings are effectively v on opposite sides of the head having advancing Y. faces inclined with respect to the vertical and 2. In a rotaryearth-boring drill, a cutting head comprising a body provided with at least four circumferentially spaced teeth, two of the teeth bey ing disposed-on opposite sides of the head and having advancingrfaces inclined with respect n Y, to the vertical, said teeth likewise having stepped According kto conventional praclower cutting edges, therother teeth beingV interposed with respectjto the first-named teeth and having substantiallyV Yvertical ladvancing faces,

cumferentially spaced teeth, two of the teeth being disposed on Voppositesides of the head and having advancing faces inclined with respect to the vertical, said teeth also'having at leastjtwoY stepped lower-,cutting edges, the other teeth being interposed with respect'toV the first-named teeth and having substantially vertical advancing faces,V said last-named teeth likewise having at least two stepped lower cutting edges and to Y extending to adiameter beyond the outer diamy eterof the rst-namedfteeth'the lowermost cutting edges of all the teeth being substantially` coincident withY respect to a common plane normal to the'axis of rotation of thedrill, the uppermost lower cuttingv edges of the first-named teethbeing at a lower elevation than the uppermost lower cutting Yedges of the second-named Y teeth. Y

4. In a rotary earth-boring'drill, a cutting head comprisingV a. Vbody`provided with atleast four circumferentially spaced teeth, two of the teeth on opposite sides of the head having advancing kfaces inclined with respect to the vertical and having stepped lower cutting edges, the other teeth being interposed with respect to the rstnamed teeth and having substantially vertical advancing faces, said last-named teeth likewise having stepped lower cutting edges and extending to a diameter beyond the outer diameter of the first-named teeth, the body being provided with ports for the delivery of lubricating mud directly to the advancing faces of all of the teeth, there being a port for each of the teeth, with each port discharging downwardly into a region intermediate the edges of the associated advancing face.

5. In a rotary earth-boring drill, a cutting head comprising a body provided with at least four circumferentially spaced wing teeth, two of the wing teeth being disposed on opposite sides of the head and having ladvancing faces inclined with respect to the vertical, said teeth also having at least two lower cutting edges stepped to cut on areas at different diameters, the other wing teeth being interposed with respect to the rst-named teeth and having substantially vertical advancing faces, said last-named teeth likewise having at least two lower cutting edges stepped to cut on areas at different diameters and also having outer substantially vertical rearning edges eX- tending to a diameter beyond the outer diameter of the first-named teeth, the body being provided with downwardly-extending ports for delivering lubricating mud to the advancing faces of the teeth, there being a port for each tooth, with the discharge end of each port intermediate the edges of the associated advancing face, the discharge end of each port being substantially directly above the junction of the two areas to which the lower edges of the first-named teeth are adapted to out.

6. In a rotary earth-boring drill, a cutting head comprising a body provided with at least four circumferentially spaced wing teeth, two of the wing teeth on opposite sides of the head having advancing faces inclined with respect to the vertical and having stepped lower cutting edges, the other wing teeth being interposed with respect to the Erst-.named teeth and having substantially vertical advancing faces, said lastnained teeth likewise having stepped lower cutting edges and also having substantially vertical rearning edges extending to a diameter beyond the outer diameter of the rst-named teeth, the body having an opening therethrough for passage of a core, the outer contour of the body being tapered downwardly to form a substantially unobstructed annular lip surrounding the lower end of said opening, the lowermost cutting edges of the firstmamed teeth extending below said lip to form a core for passage through said opening.

7. In a rotary earth-boring drill, a cutting head comprising a body provided with at least four circumferentially spaced teeth, two of the teeth being disposed on opposite sides of the head and having at least two stepped lower cutting edges, the other teeth being interposed with respect the first-named teeth, and having at least two stepped lower cutting edges, said last-mentioned teeth extending to a diameter beyond the outer diameter of the rst-named teeth, the lowermost cutting edges of all the teeth being substantially coincident with respect to a common plane normal to the axis of rotation of the drill, the uppermost lower cutting edges of the first-named teeth being at a lower elevation than the uppermost lower cutting edges of the second-named teeth.

LEONARD S. COPELIN.