US1984220A - Drill rod and detachable bit - Google Patents

Description

Dec. 11, 1934.

c. LANG I DRILL ROD AND DETACHABLE BIT Filed Aug. 11, 1931 ////VAV///////,.

INVENTOR K/MU'ZKS Lar BY His ATTORNEYS V/AAAAQ Patented Dec. 11, 1934 PATENT OFFICE DRILL ROD AND DETACHABLE BIT Charles Lang, JerseyCity, N. J.

Application August 11,

4 Claims.

This invention pertains generally to tools, and pertains more particularly to tools used for drilling, cutting, etc.

Although the invention will be shown and described in connection with a rock drill, it is to be understood that it may have many other applications. 1

Many rock drills are formed by upsetting the end of 'a drill rod and forming the bit on the upset portion. Inasmuch as the bits become dull fairly quickly, a great deal of time and labor are spent in transporting the drill rods to and from the shop for resharpening, hardening and tempering purposes. The length and weight of each drill rod may be such as to make this procedure very inconvenient.

Furthermore, in view of the fact that the shop for resharpening etc. must be somewhere convenient to the job on which the drills are used, it-will necessarily be of a portable nature and therefore is very likely to be without facilities for careful control of temperatures so necessary in obtaining the best results in steel treating.

- Moreover, a large amount of steel is tied up during the resharpening process.

In view of the fact that there are more or less distinct limits in the amount of upsetting that can be done on the end of a drill rod for the formation of a bit, the sizes thereof for a particular size of drill rod are limited to a very narrow range, and it is therefore necessary to have different sizes of drill rodsfor different sizes of bits, thus further increasing the amount of steel tied up in drill rods.

The solution of this problem is quite obviously that of having removable bits for the drill rods. Various forms of removable bits have been proposed heretofore, most of which involve the use of a separate piece in addition to the drill rod and bit to connect the bit to the rod, or involve structures for attaching the bit to the drill rod which do not permit a proper transmittal of the forces from the drill rod to the bit, or do not permit easy removal of the bit from the drill rod for renewal purposes, or do not have the desired simplicity of construction to permit ease of manufacture in quantity at a relatively low cost, and to permit continued renewals of the bit without renewal of the drill rod. In many of the three piece constructions the forces from the drill rod are not properly transmitted to the bit.

Replaceable bits may be made at a fully equipped plant where steel treating can be carefully controlled. Transportation becomes a 1931, Serial No. 556,357

small item. The bits may therefore be shipped to and from the plant without much inconvenience. Furthermore a sufliciently simple construction will permit bringing down the original cost to a point where it will be less costly to discard the bits after they become dull, thus eliminating the time and trouble of resharpening.

According to my invention the bit is attached to the drill rod in such a manner that the members which hold the bit and drill rod together do not function primarily, if at all, for the purpose of transmitting the forces from the drill rod to the bit. The bit may be readily and easily removed, and in view of the fact that the attaching parts are not subjected to the forces of drilling, these parts have an unusually long life. particularly if each has been given the proper heat treatment as will be hereinafter described.

The parts for transmitting the drilling forces absorb all of the stresses of drilling, and are positioned so as to efliciently transmit the drilling forces from the drill rod to the bit.

Although the members for holding the bit and drill rod together may also function to prevent relative rotation between the bit and the drill rod during the drilling, special means may be provided, if desired, to relieve such members from the torsional stresses.

Referring to the drawing in which like reference characters are appended to like parts in the various figures,

Figure 1 is an elevation, partly in section, of the end of a drill rod with a bit attached thereto.

Figure 2 is a view on line 2-2 of Figure 1.

Figure 3 is a sectional elevation of the end of a drill rod, showing another form of the invention.

Figure 4 is a bottom plan view of the drill rod shown in Figure 3.

Figure 5 is an elevation, partly in section, showing a different form of the invention.

Figure 6 is an elevation, partly in section, illustrating a further form of the invention.

Figure 7 is a bottom plan view of the drill rod shown in Figure 6.

Figure 8 is a sectional elevation, partly in section, illustrating means for preventing relative rotation between the drill rod and bit.

Referring to Figures 1 and 2, at 10 is shown the end of a drill rod which may be of any desired form or shape. The drill rod 10 at its end 11 is provided with a socket 12, which may be formed in the end of the drill rod 10 by any suitable means such as forging, drilling, cutting, etc. Bit 13 is provided with a shank 14 which conforms more or less closely to the contour of the socket 12. In Figures 1 and 2 the shank 14 and the socket 12 are shown tapered and with a circular cross section. The arrangement is such that when the shank 14 is firmly pressed or forced into the socket 12 so as to hold the bit 13 on to the drill rod 10, the end 11 of drill rod 10 firmly engages the bit 13 for instance by seating in an annular groove 15 on bit 13.

It will thus be seen that the shank 14 and socket 12 function to hold the bit and drill rod together and that the end 11 of drill rod 10, and the upper part of the body of bit 13, for instance groove 15, function to transmit all of the forces from the drill rod to the bit.

It will be noticed that the forces from the drill rod are transmitted to the bit over an annular area bounded by the inner and outer circumferences of the end of the drill rod. This annular area is shown as being continuous, but may be made discontinuous without'departing from the spirit of the invention.

By having the area over which the forces are transmitted from the drill rod to the bit bounded by the inner and outer circumferences of the drill rod, the forces are transmitted over a larger area and are also very evenly distributed over the cutting surface of the bit.

To prevent any tendency of the end of the drill rod 10 to spread I provide a circumferentially continuous or discontinuous ridge 16, which contacts and fits tightly against the outer circumferential surface of end 11 when the bit 13 is in place on the drill rod 10.

In practice I find it very advantageous to harden the end of drill rod 10 and to treat the shank 14 so that it will be soft. The hardening of the end of the drill rod not only increases its resistance to spreading and otherwise deforming, but also increases its resistance to abrasion. The soft shank 14, even though slightly oversize, will conform readily to the contour of the hardened socket 12. The shank 14 will conform to any inequalities of the inner surface of the socket 12 and will thus permit the end 11 of drill rod 10 to contact the upper part of the body of the bit 13, as by fitting snugly in groove 15.

It is, of course, understood that the working surface of the bit 13 has been given the proper or desired heat treatment for hardening purposes. This treatment might include the surface contacted by the end 11 of drill rod 10, if desired.

To increase the oversize tolerance for the shanks and to assist in preventing relative rotational movement between the bit and drill rod, I may provide longitudinal straight or curved grooves 17 in the wall of socket 12.

The grooves 17 will take care of a large degree of oversize in the shank 14, the excess material flowing, so to speak, into the grooves, and will grip the shank to prevent relative rotational movement. The grooves may be of any width and number.

In operation it is merely necessary to insert the shank 14 into the socket 12 in the end 11 of the drill rod 10, and to force it home with a wooden block, lead hammer or othersuitable device. When the parts are properly made the end 11 of drill rod 10 will contact the upper part of the body of bit 13. To remove the bit it is merely necessary to strike it with a suitable tool such as a lead hammer. A new bit may then be quickly inserted, and the drilling continued without more than a few moments delay.

The form shown in Figures 3 and 4 is in all respects identical with that shown in Figures 1 and 2 except that the socket 112 is given a taper of oval cross section instead of circular. The shank on the bit would have a similar taper. The cross section of the taper may have any other geometrical shape. The socket may be provided with grooves if desired.

In the form shown in Figure 5 the rod 210 has a socket 212 formed inwardly with the customary taper, but has a straight portion at its outer end, as shown at 18. The shank 214 on bit 213 is likewise provided with a straight portion shown at 19 so as to conform with the contour of the socket 212. The tapered, as well as the straight portion may have a cross section of any other geometrical shape, and the socket may be provided with grooves, if desired.

In Figures 6 and 7 I have shown a modification in which the shank 314 is formed on the drill rod 310 and the socket 312 is formed in the bit 313. The end 311 of drill rod 310 is given a geometrical shape other than circular, such as square, and fits into a recess in bit 313 of like contour, shown at 315, so that the upper surface of the recess will be contacted by the lower surface of.the end 311 when the shank 314 is forced into the socket 312. In this instance the shank may be hardened and the wall of the socket left or made soft, if desired so as to accommodate fitting.

In Figure 8 I have shown a further form of the invention in which the socket 412, shank 414 the drill rod and bit is thus prevented. Any.

other means might be substituted for the projection 20 such as roughening or knurling the end of the rod 410.

While I have particularly described several shapes of shanks and sockets it is obvious that other forms might be substituted provided the necessary wedging action and elasticity is secured between the shank and the socket to hold the bit in place and to permit direct contact between the end of the drill rod and the body of the bit so that the forces of drilling may be transmitted directly from the drill rod to the body of the bit without resort to the socket and the shank. For instance, many of the usual forms of shanks on cutters might be suitable and the usual devices thereon to prevent rotation might be substituted for those shown in the drawing without departing from the spirit of the invention.

The structure of my invention is very simple, durable, and highly practicable. The bits, for instance, might be forged in one operation and hardened in another, thus lending themselves to quantity production at a very low cost. If the bits are formed with relatively soft shanks, the inequalities in forging will be taken care of by the shank conforming to the contourof the socket in the end of the drill rod. This is particularly true if the socket is provided with grooves of any character such as those shown at 1'7. Spreading of the end of the drill rod is effectually lessened by the continuous hardened circumferential annular wall forming the end oi Itisestimatedthatthebltscanbemadein quantity so cheaply that they may be discarded much. the same as safety razor blades after becoming dull.

Having described my invention it is obvious that many modifications may be made in the same within the scope of the claims without departing from the spirit thereof.

I claim:

I. A device of the kind described comprising a drill rod, a bit, asocket in the end of said drill rod having inwardly converging circumterentialiy continuous side walls, longitudinal grooves in said socket, a shank on said bit adapted to be forced tightly into said socket and to be firmly secured in said socket solely by virtue ot the resulting i'sht fit, said grooves asinthe fltotsaidshankandsocket, said oisaiddrillrodandsaid biti'ormedsoas beflrmlylncontactwitheachotherwhen shank is in position in said socket. so that the drilling iorces will be transmitted directly from the end 01' said drill rod to said bit, and

iorholingsaiddrlllrodandbittosethenand to prevent relative rotation thereoi, the socket oi said drill being of relatively harder material than the shank of said bit.

2. Atwomemberdeviceoithekmddescribed comprisingadrillrodandabitasocketinthe endotoneoisaidmembershavinginwardly converging circumierentially continuous side walls of relatively hard material. longitudinal mitteddirectlyfromtheendofsaiddrill socket,sothatthedrillingi'orceswillbetransmitted directly from the end oi said drill rod to said bit, and said shank and socket function primarily for holding said drill rod and bit together.

3. A two member device 0! the kind described comprising a drill rod and a bit, a socket in the end 01 one of said members having inwardly converging circumierentially continuous side walls of relatively hard material, longitudinal grooves in said socket, a shank at relatively soit material on the other of said members adapted tobeioroedtishtlyintosaidsocketandtobe flrmlysecuredinsaidsocketbyvirtueoitheresultins tight at, one of said tisht fitting parts beingrelativelyhardandtheotherbeinsrelatively soft, said drill rod and said bit formed so astobeflrmlyincontactwitheachotherwhen saidshankisinpositioninsaidsockehsothat the drilling force will be transmitted directly of said drill rod to said bit. and

hcldins said drill rod and bit tcsether.

4.Adeviceoithekinddescrlbedcomprising adrillrod,a'bit.asocketintheendotsaid drill rod having inwardly converaingcircmnin said socket by virtue of the resulting 'ilt,saidgroovesinthefltoisaid .-andsocket,saidendoisaiddrillrodandsaidbit iormedsoastobeiirmlyincontact with other whensakishankkinpositicnin socketsothatthedrlllingiorceswillbe thereof.

GHARLIS LANG.

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