US2312538A - Reversible coal cutting bit - Google Patents

Description

March 2, 1943. I c FoRB s 2,312,538

REVERSTBLE COAL CUTTING BIT Filed Jan. 16, 1942 I I (I///I/ 9-- Q 1- 3mm all 0 7&6 5

Patented Mar. 2, 1943 warren stares ear nr @FFHQE REVERSEBLEL COAL CUTTING BIT Charles J. Forbes, Terre Haute, Ind.

Application January 16, 1942, Serial No. 427,049

1 Claim. (Cl. 262-33) This invention relates generally to mining'machinery, and more especially to new and useful improvements in the cutter bit and means for mounting the bit in the cutter chain block.

It is a Well recognized fact that the average cutter bit is subjected to extremely hard usage and constant replacement is necessary. For this reason, it is desirable that the cutter bit be reversible and that both ends of the bit be cutting ends. Further, it is important that simple and eiiective holding means be provided which will facilitate inserting, reversing or replacing the cutter bit under any and all conditions.

One object of my present invention, therefore, is to provide a reversible cutter bit formed at diagonally opposite ends or points with cutting teeth.

A further object of my invention is to provide improved holding means associated and co-acting with the cutter bit for holding the latter securely in place under all conditions, but at the same time allowing the cutter bit to be easily and readily reversed or replaced, as occasion requires.

A still further object of my invention is to provide a novel construction of the character specified, in which the base of the cutter bit is sup ported by and rests firmly on the upper edge of the cutter chain block.

With the foregoing and other objects in View that will appear as the nature of my invention is better understood, the same consists in the novel features of construction, combination and arrangement of parts illustrated in the accompanying drawing and more particularly pointed out in the appended claim.

In the accompanying drawing, which is for 11- lustrative purposes anly and are therefore not drawn to scale:

Figure 1 is a side elevation, illustrating the application of my invention.

Figure 2 is an enlarged detail fragmentary sectional View of the cutter bit, bit holder and upper end of the chain block.

Figure 3 is an enlarged vertical transverse section, taken on line 3-3 of Figure 1, looking in the direction indicated by the arrows.

Figure 4 is an enlarged detail horizontal section, taken on line 44 of Figure 1.

Figure 5 is an enlarged detail perspective view of the cutter bit.

Figure 6 is an enlarged detail diagonal section, taken on line 6-6 of Figure 1 and Figure 7 is a view similar to Figure 2 of the drawing, showing a modified form of my invention.

Referring to the drawing for a more particular description of my invention, and in which drawing like parts are designated by like reference characters throughout the severalviews, A designates the cutter chain block, B the reversible cutter bit and C the bit holder.

The reversible cutter bit is preferably formed from rolled stock and is of general triangular shape. Said bit is preferably one inch in width, three-eighths of an inch in thickness at the center of the base and tapers to a thickness having a radius of three sixty-fourths of an inch at its outer diagonal edge. The base I of the cutter bit is supported by and rests firmly on top of the cutter chain block A, as shown and the head 2 of the bit holder C, is formed with a horizontal transverse slot or opening 3 to receive the bit. The opening 3 is somewhat greater in Width than the co-acting portion of the cutter bit to facilitate reversal and replacement of the latter, as will presently appear.

In carrying out my invention, the outer diagonal edge 4 of the cutter bit is formed with a central arcuate recess 5, adapted to receive and co-act with the convex boss 6, formed on the outer wall of the transverse slot or opening 3 in the bit holder 0, in holding the bit firmly in place in the latter. The bit holder C is provided with the integral depending shank l, which fits in a broached opening 8 in the cutter chain block A, and is formed in one edge with a recess 9, adapted to be engaged by the inner end of the screw I 0. The screw I0 is carried by one edge of the cutter chain block and holds the shank of the bit holder securely in place.

The reversible cutter bit comprises the fiat horizontal base i, which, as previously mentioned, rests firmly on the upper edge of the cutter chain block A, the fiat side edge H, which is disposed at an angle of thirty degrees with the base, and the outer diagonal edge 4, which eX- tends between the outer ends of the base and side edge II. The opposite side faces of the cutter bit are tapered from the base I and side edge I! to the outer diagonal edge 4 of the bit to three sixty-fourths of an inch in thickness, forming the diagonally opposed cutting teeth I2. It will be noted that the cutter bit is curved or rounded at the apex of the triangle, as at 13,

' that is to say, at the corner that would ordinarily be formed at the inner ends of the base and side edge H.

My improved construction is such that the cutter bit is not only capable of double use and held firmly in position on the cutter block, but is susceptible of easy and ready reversal or replacement, as may be required under actual operating conditions. This reversibility and replacement is made possible by making the transverse slot or opening 3 in the bit holder C of greater width than the corresponding or engaging portion of the bit to permit dis-engagement and separation of the arcuate recess 5 and boss 6, after first dis-engaging the inner end of the screw l0 with the recess 9 of the shank 1.

In'the modified form of my invention illustrated in Figure 7 of the drawing, the outer diagonal edge 4 of the cutter bit B is not formed with a central arcuate recess 6, but is made solid and formed with a central convex boss I4, which fits in a corresponding recess l5, formed in the outer wall of the transverse slot or opening 3 in the bit holder. In other words, the construction is substantially the reverse 1 off, that shown in Figures 1 and 2 of the drawing, in this particular.

From the foregoing description taken rin connection with the drawing, it is thought that the construction, operation and advantages of my invention, will be readily understood, without requiring a more extended explanation.

Various changes in the form, proportions and minor details of construction may be resorted to without departing from the principle or sacrificing any of the advantages of my invention, as defined in the appended claim.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is: In a device of the character specified, a cutter chain block having a vertical socket, a bit holder having a shank extending into said socket and a head formed with a transverse slot or opening, a reversible cutter bit of general triangular form, mounted on the cutter chain block and extending through the opening in the bit holder, said cutter bit having a straight diagonal outer edge formed with a central arcuate recess extending approximately one-third of the length of said outer edge, and said cutter bit being curved or rounded ofi at its apex, a convex boss formed on the outer wall of the transverse slot or opening in the bit holder and coacting with said arcuate recess in holding the cutter bit securely in place, and means for securing the cutter bit in the cutter chain block, the transverse slot or opening in the head of the bit holder being of greater Width than the received portion of the cutter bit to allow separation of the co-acting recess and boss preparatory to reversal or replacement of the former.

CHARLES J. FORBES.

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