US2203216A - Drill bit - Google Patents

Description

June 4, 1940. M. HoKANsoN DRILL BIT 'Filed Jan. 1S, 1959 4 sheets-sheet 5 INVENTOR.

BY 840m ATTORNEY.

June 4, 1940. M. HoKANsoN DRILL BIT Filed Jan. 18, 1939 4 Sheets-Sheet 4 ATTORNEY.

yPatented June 4, 1940 PATENT OFFICE DRILL BIT Martin Hokanson,

Eidco, Incorporated, Duluth,

tion' of Minnesotay Duluth, Minn., assgnor to Minn., a corpora- Application January 18, 1939,v Serial No. 251,630

9 Claims.

/ This invention relates to percussion drills, and' this application is a continuation-in-part of my copending application Ser. No. 145,726, iiled June 1, 1937.

The principal object or novelty of the invention is that the bit has inherent exibility and which may be modified to suit the specific char acteristics or quality of the material drilled in, and for which purpose it is preferably formed of a plurality of separable parts, resulting in the following novel and advantageous features:

. Increased speed in drilling.

. Decreased gauge loss.

. Less work involved in resharpening.

. Greater number of resharpenings.

. More durable.

Less expensive to use, because any par-t that wears faster than another part can replaced when worn at less cost than the cost of a regular bit. f

' '7. Perfect fect hole.

8. Reaming and cutting edges are separate and independent of each otherand can be regulated independently of each other to suit the need of the particular drilling problem at` hand.

9. The length of the cutting edge can be regulated without affecting the gauge of the bit.

10. The cutting edge can be made to cut ahead of, in the same plane with, or follow theA reaming edge of the bit, by merely changing the length, of the auxiliary portion of the bit.

Another object is to provide a novel method of sharpening the improved bit. g

Other objects and advantages of the invention will appear in the following description thereof.

Referring now to the accompanying drawings, forming part of this application, and wherein like reference characters indicate like parts:

Figure lis a central vertical section of a bit head embodying the invention.

Figure 2 is a similar view taken at reaming quality, thus drilling a perright angles l to Figure 1.

v-us

Figure 3 is a plan view of the cutting face of the bit illustrated in Figures 1 and 2.

Figure 4 is a central vertical section of a modi- 4klied form of auxiliary portion of thebit, and is illustrative of a common cross-bit.

Figure 5 is a face view of Figure 4, illustrating howsuch an auxiliary cutting portionof the bit head may be made in separable sections.

Figure 6 is-a central vertical section of a modified form of separable bit.

Figure 'Z is a plan view of the cutting face of the bit shownin Figure 6,

of its division.

(Cl. Z-64.)

Figure 8 is a plan view of the cutting face of a bit such as shownxin Figures 1, 2, and 3 but with the auxiliary portion .thereof made in two separable halves.

Figure 9 is an elevation of one of the divisions 5 of the auxiliary portions as viewed on the plane a central vertical sectional view invention showing a Figure 10 is of a modified form of the plurality of auxiliary bits. I

Figure 11 is a face view of the cutting edge of Figure 10.

Figure 12 is an elevation of one of the auxiliary members.

Figure 13 is a similar view at right angles to-l Figure 12.

Figure 14 is a plan view of the cutting face of the member shown in Figure12.

Figure 15 is a central vertical section of a still further modiiied form of bit, particularly in re- 20 -spect to that type illustrated in Figure 6, and

showing a sharpening wheel as applied thereto. Figure 16 is a similar view of the bit taken at right angles to Figure 15.

Figure 17 is a plan View of the bit illustrated in Figures 15 and 16.

In Figures 1, 2 and 3, the body portion of the bit head is shown at l, it being hollow and having an axial bore entirely therethrough, said bore being tapered from opposite ends and decreasing in diameter from the ends to the center, and said bit head having a substantially cylindrical shank portion 2 formed integral therewith, and the tapered bore therein being for reception of the correspondingly tapered end of the bit rod 3V.' The a5 lower end of the bit head, opposite to the shank portion, is enlarged on. opposite sides as indicatedv form of depression which will produce this result, 50 whether it be conical, spherical, or otherwise, will suiiice. Obviously the depression, being formed in the end of the bit which is flattened on'opposite sides, results in the lower end of the flattened Y sides being cut away arcuately on an axis' which 55 the cutting face of 26 is at right angles to the bit axis, as is apparent from Figure 1 of the drawings.

Within the tapered bore of the enlarged end of the bit head is installed the auxiliary cutter portion 5 of the bit, it having a shank which is correspondingly tapered and frictionally held' within the bore. This cutter portion projects from the bit head within the depression and beyond the plane of the reaming edges and terminates in opposed straight cutting edges 'I--l formed by plane surfaces intersecting each other at right angles, and leads in the cutting operation. In plan view this cutter portion 5 of the bit head is illustrated as being of generally elliptical shape, although this is not essential.

In Figure 5 I have illustrated a plan view of a cross-bit type of removable auxiliary portion of bit head and in this instance having illustrated the same as being composed of four like or similar portions, divided as on the radially disposed lines 8, and it will be obvious that the cutting ledges may be installed within the socket in any relation to each other as for instance they may be all in one plane at right angles to the axis of the bit or any opposed two of these portions may be installed within the socket so that they will lead in the cutting operation, while the remaining two portions follow, etc. However, when these portions are nested together with their shank portions registering they will t within the socket in the outer portion of the bit, as a solid unit. In this connection I wish to call attention to the convenience in such a compound bit of removal of the auxiliary cutting portion. For example when the compound bit head is removed from the rod '3, access is readily had through the tapered bore of the outer portion for driving the auxiliary cutter from its socket either for sharpening, renewal, or adjustment as desired.

It is obvious that such a compound bit asv herein illustrated and described is in no respect confined to the specific form of the cutting edges here illustrated or to any particular kind of bit, as the advantages of such a novel compound bit in adapting it to specic kinds of drilling are obvious.

In Figure 6 is illustrated a modifled form of separable bit, the outermost or major portion of which, indicated at 9, is shown as provided with the tapered friction socket I0 for reception of the similarly tapered terminal II of the bit rod, and which major portion in its drilling e'ect is similar to that shown in Figure 1 of the drawings in that it forms the reaming portion of the bit, and, in this instance, is provided with an externally tapered axial plug `I2 for reception of the auxiliary portion I3, it being provided with a similarly tapered socket gagement externally of the plug I2, as illus- 'trated. It is obvious, of course, that these tapered frictional connections as here illustrated, may be the common screw threaded connections, without departing from the spirit of the invention. And it is also obvious that while I have illustrated the auxiliary portion I3 of the bit as of the chisel type, that a cross, rose, or any'type of bit may be used with equally good results.

In Figure 8 is illustrated a slightly modied form of auxiliary portion of the bit in that it is made of two separable halves divided upon the line I5; this being to illustrate how, if sol desired, the two different halves of the auxiliary portion may have unequal angles of the cuttingsedge, as more clearly illustrated in Figure 9. In all of the views it will be noted that the cutting edge 'of operation that the reaming I4 for frictional en- `needs of this particular the bit is formed by the intersection of plane surfaces at right angles to each other, but in Figures 8 and 9 it will be noted that `the cutting edge is formed by the intersection of plane surfaces one of which is from the plane of the axis of the bit, and the other 60.therefrom, and this would bring the direction of the blow, as far as cutting is concerned, 15 off from the vertical. This is quite an advantage so far as wear on the bit is concerned when the functioning of the bit 10 unequal angles, as above described, it has to be 20 diierent on one side of the center of the bit than on the other, andtherefore the auxiliary bit is formed in two the cutting edge and facture, simpler to grind, and lending themselves perfectly to mechanical arrangements of grinding. The two pieces when driven in the bit will make just as solid a connection as if they were of one piece, and if it should be desired that one 30 side lead or Work ahead of the other side all that is necessary is to drive them in a little unevenly. 'I'his arrangement of cutting edges is also applicable to the bit shown inlFigure 5.

In Figure 10 is illustrated a bit having two op- 35 posed auxiliary members I6 frictionally held within the major. member I1, and it is obvious that there'may be any desired number of such auxiliary members depending largely upon the size of the bit being used, and may be of chisel, 441

cross, rose orany other type and so installed las to lead in the cutting operation or follow in respect to the reaming portion of the bit as desired. In this modication I have shown the reaming edge as being slightly diierent in form from that of the other embodiments of the invention.

Thus I have provided a bit wherein consideration is given to the fact that the reaming and the cutting the bits thus far described are provided with reaming and cutting edges which are separate and distinct from one another and therefore adjustable4 in relation to eachother to suit the need of the particular drilling problem at hand. For in-.` 5.3

stance it may be desired for a particular drilling edges 'of the bit ro`- tate in immediate advance when drilling. In Figure 3 it will be noticed that the' two elliptical portions longest diameters at right angles to each other,- and therefore the cutting edge is exactly midway between the reaming edges as the bit rotated in drilling. Thus, if, as before stated, it is desired that the reaming edge advance ofthe cutting edge, the cutting edge could be loosened and rotated upon its axis, or within the socket, anticlockwise about 45, thege/ tightened, and thus provide .a bit to meet the drilling problem. however, there is a question of the eilicient and quick discharge of the material cut, it may be found that the reaming edge should; follow the cutting edge, in which event the cutting edge would be rotated lclockwise in with the vertical. Consequently 15 halves at right angles to along its longitudinal axis, providing two pieces just alike, simpler to manu- 25 vwork performed vby the bit are two separate functions thereof, and, as a consequence,

of the cutting edge of the bit vhave their 80 rotate immediately in d5 If, fl

ts socket about 45, and there tightened. It'is thus apparent that the drilling operator is provided with a bit having heretofore unheard of flexibility, making research possible for any drilling problem, and with the consequent lessening of the cost thereof.

In Figures 15, 16 and 1'7 is illustrated a type of bit, comprising a body portion 25, attached at one end to a drill rod indicated at 26, saidbit embodying a somewhat modied form to that shown in Figure 6 of the drawings, and wherein the axial portion 20 thereof is extended beyond the plane of the reaming edges 2l forming the integral central cutting portion, and the straight cutting edge 22 of which is preferably only in length equal to the `distance transverse the opposed corners of one of the reaming edges 2l, this being particularly convenient in sharpening said reaming edges with a hollow conical grinding wheel such as illustrated at 23.

It is to be noted that'the axially disposed cutter 20 is of straight cylindrical form which is of advantage in maintaining the sturdiest possible cutting edge of`that portion of the bit,` it being well known that where such a chisel shaped bit is formed with the side walls tapered inwardly, the arcuate edges adjacent the-corners of such chisel shaped bit do not support the corners of the cutting edge in an equally emcient manner and permits of greater grinding areaof the hollow conically shaped grinder for the reaming edges. Y

This integral form of head obviously provides means for modifications in the discharge of uid to remove the bit cuttings, in that such discharge may consist of the axial4 hole 24 through the central cutter or it may' consist of a plurality of diagonal openings, such as indicated at 25, bring ing the discharge of the iiuid, whatever it may be, well above the danger zone of plugging, which, normally occurs under some instances in drilling. i

It is to be noted too that while I have illustrated in all of the accompanying drawings that form of uniting the separable parts of the bit and Aoperating `rod as employing tapered friction joint connections, it is to be understood that other formsV of connecting said parts may be resorted to without departing from the spirit of the invention.

Furthermore it will be noticed in the several views that the cutting edge is working deeper in the hole drilled than the reamingedges, and also that thelength of the cutting edge' is not as long as the diameter of the hole drilled. This increases the speed of cutting since a smaller bit cuts faster than a larger one of the same design, all things being equal. So that with this arrangement we are cutting a hole of smaller ,diameter than desired and then reaming the hole to size with the reaming edges. Thus thereaming edges do more than merely ream the hole, but since the cutting edge isworking in a4 plane lower than the plane of the reaming edges, the latter are breaking loose the outside ring not covered bythe cutting edge, but which gives way easily as soon as the reaming edge starts to penetrate. There is much less work connected 1 with reaming this outer part thanl would be required to cut the hole to its full diameter in the first instance.

It is .also conceivable that in certain kinds of material drilled in, it may be desirable. to havey the reaming edge lead inthe drilling, and, if so,

the drill 'operator wculd simply remove the cenv ing a cutting edge extendable entirely across 4from one of the flattened sides to the other.

. intersecting the outer walls of saidenlargement trai cutting portion and replace it with one shorter in axial length so that when installed the cutting face thereof would not reach to the same plane as that of the reaming edge. 1n this type of bit the Ireaming edge is cutting a de- 5 pression allA around the perifery of the hole, leaving a central c ore which is cut by the cutting edge and as a result it breaks up in larger pieces on account of the cut on the perifery which results in faster cutting.` i

It is apparent that in all of the modiiications illustrated, the inner wall ,of the cutting edge of the reaming portion is formed by the walls` of a. conical depression` within the face of the bit, this being true even where a. plurality of removable auxiliary bits are employed, as in Figures 10 and 11, such conical depressions being illustrated at I8 in these figures, the axis of said cones being coincident with the axis of the removable bits. This as is obvious providesmost convenient means for resharpening the inside of the cones by the use of a cone shaped grinder. Having thus described my invention, what I claim and desire to secure by Letters-Patent, is: 1. A drill bit consisting of -a hollow head flattened on opposite sides, the outermost lower portions of which are formed with a pair of cutting edges lying substantially in the same circle, and al central removable cutting portion hav- 2. A drill bit consisting of a hollow head fiattened on opposite sides, the outermost portions of which are formed with a pair of arcuate cutting edges lying in the same circuit, a conical depression intermediate of said cutting edges, and a cutting portion removably installed within said depression and having a cutting edge less in length than the distance between said arcuate cutting edges.

3. A drill bit consisting of a unitary conically concaved head portion flattened upon two opposite sides and the other more remote opposite sides being formed with substantially V-shaped arcuate cutting edges lying in the same plane, and a removable auxiliary cutting portion mounted within the concavity of said head portion.

4. A drill 'bit consisting of a unitary concaved head portion flattened upon two opposite sides to providev clearance for the bit cuttings, with the other more remote opposite sides `being formed with arcuate cutting edges, said edges being formed by a conical depression in said concavity, and a removable auxiliary'cutting portion mounted within said conical depression.

5. A drill bit consisting of a unitary hollow head portion flattened on vopposite sides and having a conical depression therein forming the outermost portions oi said head into diametrically opposite arcuate reaming edges lying in the same circle, and a cutter portion -removably installed axially within said conical depression.' .l

6. A drill -bit consisting of a unitary hollow head portion comprising a substantially cylindrical shank with an enlargement upon two opposite sides adjacent the workingface ofthe bit, a conical depression within said bit, the opposite walls ofsaid depression extending to and l 70 and resulting in a pair of opposite arcuate cut- L ting edges lying in the same circle and in a plane at right angles to the bit axis and the other opposite walls of said depression being arcuately cut-away on an axis at right angles to said bit u projecting from said same circle and the opposite attened sides being cut-away to provide clearance for the bit cuttings, and a cutting portion having acutting edge extending in a direction from one flattened side to the other.

8. A drill bit consisting of a relatively short unitary hollow head portion comprising a substantially cylindrical shank portion at one end' with an enlargement upon two opposite sides of the other end, said enlargements resulting insaid other end being substantially elliptical in plan view, a conical depression within said other end l, resulting in the outermost portions thereof being formed with a pair of arcuate cutting edges and the remainder of said other end being cut-away to provide clearance for the bit cuttings, and a central cutting portion having a straight cutting edge extending in a direction from one of the flattened sides to the other.

9. A rock drill bit consisting of a. head portion 4which constitutes the working end of the bit,

said head portion having a major axis and a minor axis, the major axis being the full diameter of the hole to be drilled and the minor axis being of lesser diameter, said head portion having a depression in said'working end forming the working portions of 4said head into diametrically opposite arcuate reaming edges, the portions of the lower edge of the bit between the arcuate reamin'g edges being cut-away to permit lateral escape of the bit cuttings, and a central cutting portion within said depression and having a cutting edge less ein, length than the major axis, the walls of said depression being an element of a solid of revolution theaxis of which is coincident with the longitudinal axis of said bit, whereby said arcuate cutting edges may besharpened by a. suitably shaped end grinder revolving about an axis coincident with the longitudinal axis of the bit.

MARTIN HOKANSON.

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