US1462681A - Mining-machine bit - Google Patents

Description

July 24, 1923. 1,462,681 I N. K. BOWMAN MINING MACHINE BIT Filed Dec. 15 1921 Patented Jelly 24-, 11923.

UNHTED STATES NEWTQN BOWMAN, OFBOWDTL, DEE 0.

MINING-MACHINE BIT.

application filed December 15, 1921. Serial No. 522,57t.

To all whom it may concern:

Be it brown that l, Nnwro-N K. BOWMAN, a citizen of the United States, residing at Bowdil, in the county of Stark and State of @hio, have invented certain new and usetul improvements in Mining-Machine Bits, of which the following is a specification.

This invention relates to detachable bits for mining machines and has for its object the provision of means whereby the bit will he firmly held and also to provide a con struction which will offer ample clearance for the dust present during operation of the mining machine. A further object of the invention is to provide a construction wherehy the bit will be firmly seated in the cutter har or shank and may be readily removed and reversed when necessary or desirable. These several stated objects and other objects which will incidentally appear in the course of the following description are attained in such a construction as is illustrated in the accompanying drawings, and the invention consists in certain novel features which will be particularly pointed out in the claims following the description.

Tn the drawings I Fig. l is a perspective view of my improved hit applied to a cutter bar or shank of a mining machine;

Fig. 2 is a longitudinal section through the bit and the parts cooperating therewith;

"Fig. 3 is a transverse section on the line 33 of Fig. 2;

Fig. 4 is a detail side elevation of the bit;

Fig. 5 is a detail section of the holder or clamp taken on the line 5--5 of Fig. 1.

lln the drawings, the reference numeral 1 indicates a cutter her or shank which forms a part of an endless chain of cutters which are generally employed in coal-mining machines. In the present instance, the tree or working end of the cutter bar or shank ismade convex and inclines from the front edge to the back edge of the bar, as shown at 2. Excessive contact hetween the 'end of the her and the wall of the mine is thus avoided and clearance for dust hack of the bit is provided. Disposed longitudinally in the front edge of the loar is a seat 3 which is concave at its back wall and the side walls of which converge from the upper and lower sides of the cutter bar, as shown most clearly at 4 in Fig. 3. The seat 3 extends. through th c'extremity of the cutter bar, as shown at 5, where a substantially and has a convex longitudinal ridge 8 which, as clearly shown in the drawings, is caused to follow an arc of the same radius as the back'wall or apex of the longitudinal seat 3. The hit is hollow, as indicated at 9, although its walls are of sufficient thickness to possess the strength necessary to overcome the resistance ofiered by the vein of coal to its operation, and the edges of the side walls of the hit are so formed as to present concavities 10 at each end which follow arcs W of shorter radii than the are back ridge 8 of the bit. By reference to Fig. 41, it will be readily noted that the lines upon which the front and back edges of the hit are formed present a sharp point ii at each end thereof and this point 11 constitutes the primary cutting agent. The edges 10 are also sharpened so that the hit will readily out into and break oh the coal in clean lumps of appreciable size and, in actual practice, the hack of the bit is of relatively soft metal while the cutting edges are hardened. The active point of the hit projects beyond the extremity of the cutter har or shank and there is, consequently, ample clearance hack of the hit for the talling chips and dust, while the peculiar formation of the hit will permit it to rest firmly in the seat 3 so that the thrust upon the cutting faces or points or edges will he transmitted to the cutter bar. llnasmuch as the back of the bit is of relatively soft metal, the slight wear which may occur between the hit and its seat will serve to fit the opposed surfaces to each other so that after the hit has heen used for a time it will possibly engage its seat more firmly and evenly than when first produced. The peculiar shape or the working "faces of the hit, as well as the defined hy the hardening of the same. will cause the hit I to he self-sharpening so that it will need no attention for a long period. Between the concave arcuate portions of its edges 10, notches 12 are provided in the edges of the hit. thereby producing shoulders 13 suhstantiallv transverse to the respective edges. To retain the bit in its seat, I provide a holder as will be presently set i ice or clamp 14 which is in the form of a 1008 or stirrup adapted to fit over the hit an the end of the cutter bar and is equipped with a set screw 15 in its head which is adapted to be turned home against the back edge of the cutter bar and thereby draw the front end of the loop into close engagement with the bit and bind the bit to its seat. As shown most clearly in Fig. 5, the outer faces 16 of the holder or clamp converge toward the outer end of the cutter bar, this formation tending to reduce the liability of frictional wear upon the holder through contact between the sides of the same and the vein of coal. The front end of the holder or clamp is provided with an internal rib 17 which is adapted to enter the grooved or hollow portion 9 of the bit and, when the bit is in working position, the outer shoulders 13 will abut the outer edge of the holder or clamp, as shown clearly in Figs. 1 and 2, so that the thrust will be transmitted through the bit to the holder. In the opposite sides of this rib or boss 17 1 provide cavities 18 which, as shown by dotted lines in Fig. 2, present shoulders to be en; gaged by the rear shoulders 13 of thebit when the latter is in its working position, the portion of the rib intervening between the cavities 18 extending between the corresponding shoulders 13 so thatwhen the set screw is turned home, the bit will be in interlocking engagement with the holder or clamp and movement of the bit in either direction through the clamp will be positively prevented. The shoulders 13 are obviously formed at the widest part of the bit, the sides of the bit tapering in both directions towards its end or extremities whereby the entering points are formed, as heretofore stated and as clearly shown in the drawings. The outer portions of these shoulders will, consequently, form the widest portions of the bit, and the holder is so formed that the engagement of the shoulders with the holder will occur at the junction of its forward end wall and its upper and lower side walls respectively, the opening through the holder being, consequently. just sufficient to admit the cutter bar so that the portions of the holder engaged by the bit pass through the notches 12 of the bit and through the cutaway portions 6 of the cutter bar. To permit the bit to be engaged in the holder, I provide on the inner faces of the top and bottom walls of the holders grooves 19 which merge into the cavities 18, as shown most clearly in Fig. 5. As the extreme width of th bit is greater than the width of the opening through the holder, these grooves permit the bit to be readily engaged in the holder inasmuch as the bit may be inserted in the holder with its widest portion disposed along the length of the holder, and if a quarter turn be then given the bit in either direction, the working side of the sam will be brought into proper enga ement with the rib 17 and the seats 18, t e grooves 19 accommodating the width of the bit at the inner shoulders 13 of the same. After the bit has been thus assembled with the holder, the holder and bit are easily assembled with the cutter bar by merely inserting the end of the cutter bar through the holder and then turning home the set screw. When the parts are thus assembled, the bit will be held firmly and positively against movement in any direction and will be enabled to effectually overcome the resistance thrust upon it by the vein of coal. Obviously, when one end or point of the bit has been worn to such an extent as to be no longer fit for practical use, the bit may be removed from the holder and the cutter bar and then reversed so that the formerly inactive point may be utilized.

Having thus described the invention, what is claimed as new is:

1. The combination of a cutter bar having :a longitudinally extending concave seat at its free end and provided with a notch at the end of said seat forming a terminal of the seat, a bit having its sides iiared and its back forming a longitudinally extending convex ridge adapted to fit in the said seat, the forward side of the bit being provided with concave arcuate portions merging into the back of the bit to form cutting points, a holder fitting around the bit and the cutter bar, and means carried by the holder to engage the cutter bar and bind the bit in the seat.

2. The combination of a cutter bar having a longitudinal seat in its front edge at its free end, a bit adapted to fit snugly in said seat and provided centrally with spaced shoulders on its forward side, said shoulders being disposed in advance of the sides of the seat, a holder adapted to encircle the end of the cutter bar and constructed to engage the bit between the shoulders thereon and between the inner shoulder and the inner end of the bit, and means for securing th holder rigidly upon the cutter bar.

3. The combination of a cutter-bar having a longitudinal seat at its free end in its front edge, the front side of said seat being open, a bit adapted to fit snugly in said seat and provided centrally with spaced trans.

verse shoulders on its front side, the said shoulders being in advance of the sides of the seat, a clamp fitting around the free end of the cutter bar and provided internally with a cavity to receive one transverse shoulder of the bit whereby the body of the clamp between its outer edge and said cavi? may fit snugly between and interlock wi the shoulders on the bit, and means for securing the clamp firmly upon the cutter bar.

4, The combination with a cutter bar havgreener ing a longitudinal seat in its nt edge et its free end, of a symmetrical reversible bit adapted to fit snugly within said seat with either end projecting through the end of the cutter bar and its opposite end housed in the seat, and provided centrally with speced shoulders on its working side, the bit tapering from said shoulders toward both its ends, a holder fitting around the cutter bar at the free end of the same and having a bit-engaging portion constructed to inter lock with the said shoulders and bind the housed end of the bit within the seat, and means for securing said holder upon the cutter her.

5. The combination of a cutter bar having a longitudinally extending seat at its free end, a bit fitting snugly in said seat andheving its side walls flaring outwardly at its center and converging toward its ends, notches formed in the edges of the bit at the center thereof whereby to define spaced shoulders on the hit, a holder encircling the end of the cutter bar and the bit and hav ing a portion pessing through the notches in the bit and engaging the shoulders thereon, and means for securing said holder to the cutter her.

6. 'The combination of u cutter bar having a longitudinally extending seat at its free end, a bit adapted to fit snuglyrin said sent and having its cutting edges tapering from its center toward! its ends, spaced shoulders being provided upon said edges midwey the ends thereof, a holder encircling the end of the cutter bar and provided on its inner side with a rib to fit longitudinelly of the hit between the cutting edges of the same, the said rib heing provided in its opposite sides with cavities to acooodate some of the shoulders on the bit whereby the hit and the holder will edect interloc engagement, and means for securing the holder rig dly upon the cutter bar.

The combination of a cutter bar hav a longitudinal seat at its free end, e, bit he ing its sides flaring outwardly from its back and converging toward its ends end pro-= vided with spewed shoulders on its front edges midway its ends, a holder encircli the cutter her and provided with on intended boss to fit between the es of the bit and cavities to receive the shoulders on the bit whereby the holder may efit'ect interlocking engagement with the bit between the shoulders thereon, the holder being provided in opposite sides with oves leading into said wvities whereby to permit turning of the hit in assembling the ports, and means for securing the holder rigidly upon the cutter bar.

8. A. bit for mining machines heving spaced wells, end in longtiudinelly convex hack, the side walls diverging from the said convex back and converging toward the ends thereof, the edges or the wall being provided with notches at the centers thereof whereby to define spnced shoulders and being arouate between the seid shoulders and the ends or the heel; whereby to form concave cu tin edges.

n testimony whereof I afin rny signeture.

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