US2558341A - Auger rock drill bit - Google Patents

Description

June 26, 1951 F. L. coRY El AL 2,558,341

AUGER ROCK DRILL BIT Filed March 11, 1949 1 7.11. Hayden INVENTOHS ATTORNEYS Patented June 26, 1951 UNITED STATES PAT ENT OFFICE AUGER ROCK DRILL err Frank Lawrence Cory, Central Valley, and Ernest Albert Hayden, Callahan, Calif.

Application March 11, 1949, Serial No. 80,952

5 Claims.

This invention relates to rock drill bit construction. More particularly, the invention has reference to an improved bit, novelly designed to per- One or a combination of these conditions may complicate and make difficult the drilling operations. For example, in damp clay ground, the drilling dust tends to form around the drill stem, making a collar. Or, in caving ground small rocks will fall behind the drill bit forming an obstruction when an attempt is made to withdraw the drilling steel. time may be lost in drilling a single hole, and

very often long lengths of drill steel cannot be,

removed. In such cases, it may be necessary to drill another hole nearby in order to achieve the results desired, and subsequent blasting operations in most cases will damage the unremoved drill still beyond possible reuse.

The purpose of the present invention, accord ingly, is to save valuable time andmaterial, and to permit drilling in types of earth and rock heretofore avoided, thus to make earth excavation cheaper and many projects possible that have heretofore not been feasible, using the usual drilling methods.

To this end, we provide a rock drill bit which in basic essentials is conventionally formed, so

far as actual drilling of the hole is concerned;

and special cutters or augers formed on the drill shank or side surfaces of the drill bit, or at any other point back, of the cutting. face of the bit, said augers being specially designed so as, in effect, to cause the rock drill to auger its way back out of the drill hole, where-it is desired to remove the drill.

With the foregoing and other objects in view which will appear as the description proceeds, the invention consists of certain novel details of construction and combinations of parts, hereinafter more fully described andpointed out inthe claims, it being understood that changesmay be made in theconstruction andaarrangement of parts without departing from, the spirit of the invention as claimed.

Referring to the drawings Fig. l is a side elevatio'nalview of a rock drill bit and adjacent portion of a drill shank, showing one form of the invention applied thereto.

Fig. 2 is a section on line 2-2 of Fig. 1. Referring to the drawings in detail, 5 designates generally a drill shank to which is attached Thus, many hours of ,1 of the drill hole. 40

a drill bit 6 having a portion of the shank 5 constitute the head portion of a rock drill.

opening at ill on the cutting face of the bit.

The bitin the present instance is formed with,

radial cutters H defining between them depressions I2. back of the respective cutters H, said shoulders alternating with thedepressions l2, as readily seen from Fig. 2.

All. the above is conventional rock. drill bit construction and does not per se constitute the present invention.

At this point, and for aibetter understanding hr the invention, it is appropriate to discuss the manner of use and operating characteristics of,

a conventional rock drill bit as described above.

As the drilling proceeds, a blast of air. or air and water is sent through the bores 8, 9 and is blown, This is for. the purpose of carrying the drillings and small stones out of,

outthe opening II].

the drill hole.

It will be readily seen by reference to Fig. 2. that when this blast moves backwardly around, the drill bit for the purpose stated above, it will ;pass.through the spaced apart grooved or depressed portions 12 of thebit- This, of course, is because the outer side walls of the cutters ll will be in. engagement with the side wall of the drill hole so that the air blast is forced. rearward-. ;ly through the clearance spaces or depressions l2 1 between the respective cutters.

The result is that there is what amounts tea dead air space immediately behind each cutter.

II between each shoulder,l3 and the sidewall mud, andYother material tends to lodge in this dead, air space- Accordingly, when an attempt. is made to remove the drill, the drill sticks in the drill hole.

In accordance with the drill bit, said cutter members on the drill bitbeing best termed cutting augers and being generally designated by the reference numeral I4.

are applied, or on other factors. tration of the invention, four augers I4 are il-, lustrated purely forthe sake of example in ShOW-r We believe the number of these augers II can vary depending on the characteristics of the earth or rock being drilled, the particular formation of the rock drill bit to which the augers threaded socket receiving. threaded stud i formed on the shank 5. When considered together, the bit 6 and the illustrated,

Shank 5 has an axial bore 8 communicating with bore 9 of the bit, bore 9 Additionally, shoulders I3 are defined- Small hard stones, drillings,

invention, a plurality of spaced cutter members are provided as projections from the side walls of the drill shankand In the illus- Each auger [4 in its preferred form is pitched away from the cutting face of the bit, this being for the purpose of causing the drill to auger its way backwardly out of the drill. hole while still rotating in the same direction as it was rotating while moving forwardly and drilling the hole. Each auger, in this connect-ion, is pro vided with a top face I5 disposed in a plane that is at a slight angle from a plane perpendicular to the axis. of the drill. Each auger, additionall'y, has a-bottom face I6 which is at a greater angle to said perpendicular plane, said top and bottom faces converging to meet at the front cutting edge I I of the auger. Thus, each cutting auger I4 is of approximately triangular shape-,having a rear. face 18. It has been found that, in. average drilling conditions, the pitch of the bottom of the auger should be about 35 degrees, and the" top pitch about 8 degrees, to the horizontal.

We also provide another annular row of spaced augers, or more than one other row. These are disposedv more remote from the cutting face of the drill bit,. and for example they can comprise a row of cutting augers l9 locatedon the drill shank 5. Or, an annular row of cutting augers could be provided on a Washer which can be interposed between the drill shank and.

drillbit in some bit constructions.

In any event, if one or more rows of augers l9v are provided, they are of roughly thesame formation and characteristics as the augers Id. In the present instance, the augers l9 have top faces pitched like the top faces [5, and bottom faces 2|, rear faces 22., and cutting edges 23. These in the present instance do not extend laterally as far as the cutting augers M, as readily seen from Fig. 1 and Fig. 2. Rather, the first row of augers 19 can operate to chew into those cuttings whichmight otherwise bind against the enlarged lower end of the drill shank, where.- upon as the drill augers its way back out of the drill hole, the larger augers 14 can act upon those cuttings which have already been chewed up by the augers l9, and can also act upon other ctittings which are outside the reach of the augers In any event, when the drill .is to. be withdrawn, the operator continues rotating. the drill in its original direction, shown by the arrow in Fig. 2. As. the drill is withdrawn, it will drill. its way back through the cuttings, in the manner described above, causing easy and speedy withdrawaljof. the, drill. In tests continuing over a long period of time, the augers have been found to act exactly as stated above.

What is claimed is:

1,. A rock drill bit comprising radial wings,

V radial". cutting edges on the lower end of said wingsa plurality of radially extending ledge members. integral with the upper portion of the bit, the outermost surfaces of the ledge members extending outwardly from the bit axis a distance no greater than the cutting edges of the bit, said ledge members being inclined upwards and having relatively sharp leading edges, the leading 4 edges of said ledge members projecting further outward from said upper portion than the trailing edges thereof.

2. A rock drill bit as in claim 1 having in combination therewith a shank, said bit being mounted at the lower end of said shank, an enlarged bell-shaped bit receiving portion on the lower extremity of said shank, a plurality of radially extending secondary ledge members integral with i said shank and positioned on said bell-shaped portion, the outermost surfaces of said secondary ledges extending outwardly from the bit axis a distance no greater than the greatest diameter of the shank, said secondary ledge members being inclined upwards and having relatively sharp leading edges, theleading edges of saidsecondary ledge members projecting further outward from saidshank than the trailing edges thereof, said. first named ledge members extending further out ward from the longitudinal axis of the bit than said secondary ledge members.

3. In a drill a head portion including means. at one end for drilling a hole, and a plurality of radially extending: ledge members rigid with the side surface of said head portion, said ledge members having sharp leading edges and being inclined out of perpendicularity to the bit axis, the outermost surfaces of the ledge members extending outwardly from the bit axis a distance no greater than said hole drilling means.

4. In a drill ahead portion, means at one end thereof adapted for drilling a hole, and a plurality of radially extending ledge members. rigid with the side surface of. the head portion, the. outermost surfaces of the ledge members ex.- tending outwardly from the bit axis a distance :no

greater than the cutting edges of the bit, said ledge members being inclined out of the perpendicularity to the bit axis. and having relatively sharp leading edges, the leading edges of. said ledge members projecting further. outward from said side surface than the trailing edges thereof.

5. In. a drill a head portion, means. at one end thereof. adapted for drilling a hole, and a plurality of radially extending ledge membersv integral with the side surface of said head portion, the outermost surfaces of the ledge members extending outwardly from the bit axis a distance no greater than said hole drilling means; said ledge members being disposed transversely of said head portion and. being inclined slightly and having relatively sharp leading edges, the leading edges of said ledge members extending transversely of the path of rotation of said ledge members.

FRANK LAWRENCE CORY. ERNEST ALBERT HAYDEN.

REFERENCES CITED 7

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