US2248733A - Detachable bit for coal augers and the like - Google Patents

Description

July 8, 194 1. 7 QR. ANDERSON DETACHABLE BIT FOR COAL AUGERS AND THE LIKE Filed July-12, 1939 2 Sheets-Sheet i INVENTOR Cec i Z J? .Anderson u y 3, 1941- c. R. ANDERSON I 2,248,733

DETACHABLE BIT 'FOR COAL AUGERS AND THE LIKE Fild July 12, 1939 2 Sheets-Sheet 2 1 a A 27 2325 V 2] I I 4/ I INVENTOR Ce all? .25.. Anderson M, MW M Patented July 8, 1941 DETACHABLE BIT FOR COAL scenes AND THE LIKE Cecil B. Anderson, Pittsburgh, Pa., assignor to The Martin-Hardsocg' Company, Pittsburgh, Pa, a corporation of Pennsylvania Application July 12, 1939, Serial No. 284,016

10 Claims.

This invention relates to earth-boring tools and is for a detachable bit construction especially adapted for use in the boring of coal and like relatively soft formations.

It has heretofore been proposed to use a head it the working end of a coal auger having renovable or detachable bits capable of being renoved and sharpened from time to time and reilaced when necessary. Considerable trouble has ween encountered in connection with such deices, however, due to the difli-culty of keeping 1e detachable bits tight in the working heads 1 which they are mounted or, when they are ufli'ciently tight so that they do not chatter, dif- -.culty has been encountered in accomplishing the ready removal of them.

According to the present invention there is )rovided a detachable bit comprising a working lead or body adapted to be secured to the front and of a coal auger wherein the bits are tightly acid in a working position in the body but from which the bits may be readily removed when it is necessary to sharpen or replace them. According to the present invention, a common means passing transversely to the longitudinal axis of the auger holds the bits against endwise movement and at the same time applies pressure in a direction transverse to the axis of the auger tending to spring the bits or wedge them into tight frictional contact with the walls of the sockets in which they are received to thereby prevent the bits from chattering or vibrating. The invention may be readily understood by reference to the accompanying drawings in which Figure 1 is a side elevation of a portion of the coal auger and a detachable bit construction embodying my invention;

Figure 2 is a similar View at right angles to Figure '1;

Figure 3 is working head, the bit elements being shown in elevation;

Figure 4 is a transverse section in the plane of line IV-IV of Figure 3;

Figure 5 is a front end view of the working head with the detachable bit elements removed;

Figure 6 shows a modification, the view showing the auger in ele ation and the working head in longitudinal section, the bits being shown in elevation;

Figure '7 is a View similar to one of still a further modification; Figure 8 is a View similar to Figure '3 of the modification shown in Figure '7; and

a longitudinal section through the Figure 9 is also a longitudinal section similar to Figure 8 but showing the bits only partially inserted in the holder.

Referringto the drawings and particularly to Figures 1 to 5, 2 designates the end portion of a coal auger which may be of any preferred construction. It is provided with a squared terminal portion 3. 4 designates the working head which is secured to the end of the auger 2 and which carries the detachable bits 5 and 6. The head 4 is preferably formed of malleable cast steel and is of a generally twisted form providing spiral flutes or ribs 1 having a pitch conforming generally to the pitch of the flanges on the coal auger. It is provided with a square socket 8 at its rear end into which the squared projection 3 on the end of the auger 2 extends, and it is further provided with shoulders 9 which abut against the flanges of the auger for further holding the head and auger against relative rota tion.

In the opposite or front end of the working head 4 are two slot-like sockets Ill located diagonally opposite each other on opposite sides of the center of rotation of the working head. These slots extend inwardly into the body 4 at an angle to the longitudinal axis of the assembly. The slots pass entirely through the enlarged portion 4A at the front of the body 4 and termiri'ate at shoulders 42) (see Figure 3). The body 4 at :a point intermediate its ends is so narrowed that the inner ends of the slots adjacent the shoulders 4b open at opposite sides of the head, as shown in Figure 3.

The cutters 5 and 6 are formed of pieces of steel of generally rectangular cross section, the cross section of the shanks of the cutters 5 and 6 being of the shape and approximate size of the slots it so that the shanks may be received in the slots with the ends of the shanks of the cutters abutting against the shoulders 42). The front terminal portions of the cutters are properly shaped toform cutting surfaces. By reason of the inclination of the slots It with reference to the longitudinal axis of the assembly, the shanks of the cutters cross one another as shown in Figure 1, but they are separated by an intervening solid body of metal indicated at 40 in Figure 3. Passing diametrically through the enlarged end part do of the head 4 is a tapered key-way 4d. This key-way is located at approximately the point where the longitudinal center lines of the shanks of the two bits cross each other. Each bit preferably has a shallow channel ll formed on the inner face of its shank positioned to coincide with this key-way. A transverse key l2 having a slight taper toward one end is driven into the opening 4d from one side of the head and, as shown in Figure 4, is preferably of a length such that its terminal portion 12a projects a slight distance beyond the side face of the head at the other side of the head from which it is entered. The transversely extending key l2 has two functions. First, being received in the channel or grooves H in the shanks of the bits, it prevents the bits from being pulled out of the head 4 in an endwise direction. Secondly, by reason of its slight taper, it tends to spread the shanks of the two bits apart in a direction transverse to the longitudinal axis of the assembly thereby causing the bits to be wedged outwardly against the confining walls of the slots and thus held from chattering or vibrating.

To remove the bits it is merely necessary to tap the projecting end I2a of the key l2 to drive the key out of the key slot. If the bits cannot then be easily removed, the inner ends of the bits where they abut against the shoulders 4b are exposed and by inserting a screwdriver or other wedging implement between the ends of the bits and the shoulders 4b, they can be readily 100sened and thus be removed;

The slots forming the sockets are inclined with respect to the longitudinal axis, as best shown in Figure l, in order to enable substantially straight cutter bits to be used and get the proper degree of spread or flare for the end of the unit. If desired, these two holes or sockets may, as shown in Figure 3, also converge outwardly to a slight extent so as to bring the cutting portions of the bits into proper relation with one another.

In the embodiment of the invention shown in Figure 6, the bit-carrying member or working head I5 is of the general form shown in Figure 1 and fits onto the end of the auger 2' in the same way. Its working end is provided with an enlarged part He, and there are two slots l5 therein positioned similarly to the slots I and inclined in a similar manner with reference to the longitudinal axis of the assembly. Into each of the slots I is inserted the shank of a cutter I1, the cutters also being generally of the form shown in Figures 1 and 2. Between the two slots 16 there is a body of solid metal l5b. The working head is so formed that extensions of the slots I6 beyond the portion I511 of the body are channels which receive the inner ends of the bits, these channels terminating in shoulders I50 against'which the ends of the bits abut. The portion of metal l5d separating the two channels is preferably of inwardly decreasing thickness. Instead of the bits being retained in position by means of a wedge or key, as previously described, the modification shown in Figure 6 comprises the use of a bolt [8 which passes through the shanks of the two bits and also passes through the body of metal l5b which separates the two bits, the head of this bolt being exposed at the side of the member l5. On the opposite end of the bolt is a nut l9 which is also exposed at the opposite side of the member I5. The shanks of the two bits are provided with holes through which the bolt passes. When the nut I9 is screwed down tight- 1y, pressure is applied to the shanks of the two bits in a transverse direction tending to force the bits into tight frictional engagement with the walls of the slots l6, and this frictional engagement is increased by the slight taper in the portion lid which enables the shanks of the bits to be sprung to a very slight extent. In this construction the bits may be removed merely by removing the nut l9 and taking out the bolt I8. As in the construction previously described, the inner ends of the bits are accessible at the sides of the body l5 so that after the fastening means is taken out, if the bits still stick, they can be pried out by a working tool inserted between the ends of the bits and the shoulders I50.

In the modification shown in Figures 6, 7 and 8 the arrangement is generally similar to that shown in Figures 1, 2 and 3 except that a slightly different construction is provided for holding the cutter bits against endwise movement. In this figure 2a designates the body of the auger and 20 designates the head at the working end of the auger which carries the cutter bits 2|, these being generally similar to the cutter bits 5 and 8 of Figure l. The head or body 29 is provided with slots or cavities 23 which open inwardly from the end of the body, the two cavities or recesses 23 terminating in a common opening 24 at the working end of the head. At the inner end of each of the slots 23 is a transverse opening 25, there being a shoulder 26 at the inner end of each of the cavities 23.

The cutter bits 2| are provided on their inner ends with laterally projecting lugs 27. Passing transversely through the head is a key slot or opening 28 in which is removably inserted, transversely extending key 29.

In this arrangement the cutter bits are inserted endwise into the opening 24, then they are moved laterally into line with their respective recesses or cavities 23. Then they are pushed endwise into the cavities until the lugs 2'! project through the openings 25. When they are in this position the key 29 is driven into place. This wedges the inner ends of the bits apart, serving to firmly lock the lug portions 21 in the openings 25 and thus hold the bits against endwise movement. The key 28 also tends to spring or spread the shanks of the two bits apart and thus hold them from chattering during the operation of the drilling. This arrangement avoids any necessity for the accurate positioning of the key-ways in the shanks of the bits, as required by the construction illustrated in Figure l and, at the same time, firmly holds the bits against endwise movement independently of the key 29. This arrangement also enables the shanks of the bits to be sprung by the key 29 because of the fact that the shanks of the bits do not make contact with the walls of the cavity throughout the entire length of the cavities 23.

In the several arrangements, which are merely illustrative of the various ways in which my invention may be embodied, means passing transversely through the working head serves to simultaneously lock the bits against lengthwise movement and exert pressure on the bits in a transverse direction for holding them tightly in their sockets and preventing them from vibrating or chattering or otherwise getting out of place. This manner of holding the bits is very effective even though the shanks of the bits are otherwise fairly loose in the slots or openings in which they are received. At the same time the device is simple and cheap to construct and can be conveniently used in the field.

While I have illustrated and described certain specific embodiments of my invention, it will be understood that it may be otherwise constructed and embodied within the scope claims.

1. A bit structure. of the class described comprising. a body member, said member having an opening therein at the end face thereof, which opening forms a bit-receivingsocket, a cutter bit having a shank portion of rectangular cross section which shank portion is received in the socket, and means passing transversely through the body and having an interlockingengagement with the bit for holding. the bit against longitudinal movement and constructed to simultaneously exert pressure in a direction normal to the wide faces of the shank of said bit to keep the bit in tight frictional contact with one wall of the socket.

2. A bit structure of the class described comprising a body member, said member having an opening therein at the end face thereof, which opening forms a bit-receiving socket, a cutter bit having a shank portion of rectangular cross section which shank portion is received in the socket, and means passing transversely through the body and having an interlocking engagement with the bit for holding the bit against longitudinal movement and constructed to simultaneously exert pressure in a direction normal to the wide faces of the shank of the said bit to keep the bit in tight frictional contact with one wall of the socket, said socket being also open at its inner end whereby access may be had to the inner end of the shank of the bit for driving it out if the bit becomes stuck in the socket.

3. A bit structure of the class described comprising a body member, said member having an opening therein at the end face thereof, which opening forms a bit-receiving socket, a cutter bit having a shank portion of rectangular cross section which shank portion is received in the socket, and means passing transversely through the body and having an interlocking engagement with the bit for holding the bit against longitudinal movement and constructed to simultaneously exert pressure in a direction normal to the wide faces of the shank of the said bit to keep the bit in tight frictional contact with one wall of the socket, said socket terminating at its inner end in a shoulder accessible at the side face of the body and against which the inner end of the shank of the bit may abut.

4. A detachable bit structure comprising a body member, said member having a pair of openings extending into it from the end face thereof, said openings being on opposite sides of the 1ongitudinal axis of the body and forming bit-receiving sockets, there being a partition formed by the body between the two sockets, a pair of cutter bits having shank portions of rectangular cross section, the shank of one bit being received in each socket, and a common securing means passing through said partition for simultaneously holding both bits against longitudinal movement and which simultaneously applies pressure to both bits in a direction at a point intermediate the ends thereof and in a direction normal to the wide faces of the shanks for holding the bits in tight frictional contact with the walls of the socket in which they are received to thereby restrain them from chattering.

5. A detachable bit construction comprising a body member for attachment to the end of an earth-boring auger, said body member having a pair of openings extending into it from the end face thereof at opposite sides of the center of rotation thereof, said openings providing bitreceiving sockets, there being an integral portionof the body providing a partition between said sockets, a cutter bit of rectangular cross section in each socket, and means passing transversely through the part of the body forming the partition and having an interlocking engagement with both of the bits arranged to simultaneously hold the bits against endwise movement and to apply pressure to. the bits in a direction normal to the width of the bits to increase the frictional contact between the bits and one wall of their respective sockets.

6. A detachable bit construction comprising a body member for attachment to the end of an earth-boring auger, said body member having a pair of openings extending into it from the end face thereof at opposite sides of the center of rotation thereof, said openings providing bit-receiving sockets, there being an integral portion of the body providing a partition between said sockets, a cutter bit of rectangular cross section in each socket, the portion of said body which is between the sockets having a key-way passing diametrically through it transverse to its longitudinal axis, a wedge in said key-way which bears against the wide faces of both bits, the wedge serving to hold the bits in tight frictional contact with one wall of their respective sockets, the wide faces of the bits being transversely grooved for interlocking engagement with the wedge whereby the wedge also locks the bits against longitudinal displacement.

7. A detachable bit construction comprising a body member for attachment to the end of an earth-boring auger, said body member having a pair of openings extending into it from the end face thereof at opposite sides of the center of rotation thereof, said openings providing bit-receiving sockets, a cutter bit of rectangular cross section in each socket, and a bolt passing diametrically through the body transversely of the longitudinal axis thereof and through portions of both of the bits in the direction of the minimum thickness of the bits, said bolt having a nut thereon, said bolt and nut bearing directly against the bits and serving to apply a pressure thereto in a direction transversely of the longitudinal axis of the body for holding the bits against vibration.

8. A detachable bit construction comprising a body member for attachment to the end of an earth-boring auger, said body member having spiral flutes thereon to form an extension of the auger, the body having a pair of openings extending into it from the end face thereof, said openings providing bit-receiving sockets, the openings being inclined with respect to the longitudinal axis so that the two sockets cross one another, the outer ends of the openings being on opposite sides of the center of rotation of the head, the two openings being diagonally positioned with respect to one another, a bit in each of said sockets projecting beyond the end of the body, and means passing transversely through the body in that portion of the body where the two sockets cross each other having an interlocking engagement with both of the bits for holding the bits against endwise movement, said means also being arranged to apply pressure to the bits in a transverse direction for holding the bits in tight frictional contact with the walls of the respective sockets in which they are located.

9. A detachable bit construction comprising a body for attachment to the end of an earth-boring auger, said body having a pair of cavities extending into it from the end face thereof, said cavities being disposed on opposite sides {'of the center of rotation of the bit, the cavities providing bit receiving sockets, the body having transverse openings therein at the inner end of each cavity, a bit in each cavity projecting beyond the end of the body, the inner'end of each bit having a lug portion that projects through the transverse opening at the base of its cavity, and means extending transversely through the body for wedging the bits apart in a direction to force the lugs into the said openings.

10. An attachment for the ends of earth boring drill bits comprising a body member having two pockets entered into it from an end face thereof, the pockets being of rectangular cross section and terminating at shoulders formed at the inner ends of said pockets by a portion of said body, said pockets being operated by an interfitting partition forming a part of said body, a cutter bit having a shank of rectangular cross section entered into each pocket and having its inner end abutting against the shoulder at the end of the pocket, and means passing through said partition and engaging the shanks of both cutters and applying a pressure against the shanks of said cutters normal to the face of the shank which is contacted thereby, thereby tending to press the bits laterally against the Walls of the pockets to retain them in place and restrain them from vibrating.

CECIL R. ANDERSON.

Patent nof gglpsflx.

Iti

of the above numbered patent requ im 10, for the word 0nd column, line cla and that the said Letters Patent inthat the same may conform to Signed and sealed this 25rd day of (Seal) CER'II FI GATE OF C ORREC'TI ON s hereby certified that error 'appe July 8, l9lll CECIL R. ANDERSON.-

should be read with the record of the case September, A. D. l9b l.

Henry Van Arsdale, Acting Commissioner of Patents.

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