US2691785A - Machine for splitting the ends of - Google Patents

Description

Oct. 19, 1954 w E 2,691,785

MACHINE FOR SPLITTING THE ENDS OF MINE ROOF BOLTS Filed Feb. 17, 1950 2 Sheets-Sheet l CLAUDE C .WHITE GHOI- nay:

C. C. WHITE Oct. 19, 1954 2,691,785 MACHINE FOR SPLITTING THE ENDS OF MINE ROOF BOLTS Filed Feb. 17, 1950 2 Sheets-Sheet 2 CLAUDE 0. WHITE I as, 0

case.

Patented Oct. 19, 1954 UNITED STATES PATENT OFFICE MACHINE FOR SPLITTING THE ENDS OF MINE ROOF BOLTS 4 Claims. 1

In carrying out mineral mining operations, and particularly coal mining operations, a presently used method of supporting roof strata to prevent collapsing of the roof of the mine cave or tunnel, consists briefly, of excavating holes in the roof by boring or otherwise to extend them upwardly from the roof ceiling through the strata between the top of the roof of the tunnel and the surface of the earth. A rod or bolt is then insorted in each hole. The bolt is split at one end and is equipped with threads at its opposite end. Before the bolt is inserted in a hole a wedge is initially associated with the split end of the bolt. This end of the bolt is then inserted into the hole and as the bolt is forced inward within the hole and driven home the wedge at the innermost end of the hole causes the split portions of the bolt to be expanded for the purpose of holding the bolt in place, with the lower threaded end depending from the roof into the tunnel. A washer is then sleeved onto the exposed end of the bolt after which a nut is screw-threadedly engaged with the threaded end of the bolt and tightened.

Bolts or rods employed in this manner have been found, in effect, to tie together the overlying roof strata and thereby provide a strong and enduring mine tunnel roof.

The principal object of the present invention is to provide an improved bolt or rod for use in the above referred -to method of supporting mine tunnel caves or roofs, together with an improved method of, and machine for, producing the same.

The mine roof supporting bolt or rod of this invention is characterized by having that end thereof that is to be expanded by the wedge for thepurpose above stated, split by a shearing action as distinguished from the presently known and used methods of splitting such bolts or rods, whereby is provided a bolt of greater strength and holding action than has heretofore been the Further, in accordance with this invention, there is provided a method for so shearing the bolt that the splaying incident to the shearing operation will not adversely affect the normal strength of the bolt as now characterizes and renders undesirable the presently employed means and methods for splitting bolts designed for use in mine tunnel roof supporting methods.

Also, in accordance with this invention, there is provided a simple and efiicient machine whereby the above mentioned method contemplated by this invention may be cheaply and economically performed and bolts having the desirable characteristics contemplated by this invention mass produced at low cost.

The machine of this invention is characterized by such a construction, combination and arrangement of parts that it performs its intended function without in anywise distorting the shape of the bolt or rod operated upon and is therefore a material improvement over such machines as are known and have heretofore been employed for splitting metal bars or rods.

The invention, together with its objects and advantages, will be best understood and appreciated when the following detailed description thereof is read with reference to the accompanying drawings, wherein is illustrated what is presently considered .a preferred application of the invention and in which:

Figure 1 is a perspective view of a machine designed in accordance with this invention for providing mine tunnel roof supporting bolts having the characteristic features of this invention.

Figure 2 is an enlarged fragmentary perspective view for more clearly showing the position of the shearing plates at both the beginning and end of the shearing operation.

Figure 31s a fragmentary enlarged detail perspective showing the position assumed 'by the shearing plates towards the end of the splaying operation.

Figure 4 is an enlarged view of the machine as seen from one end thereof, with certain parts shown in elevation and other parts broken away and shown in section to illustrate certain details of the machine.

Figure 5 is a detail vertical sectional view taken substantially on the line 5-5 of Figure 4, and looking in the direction of the arrows; and

Figure 6 is a fragmentary peripheral elevational view of a tunnel roof supporting bolt or rod as contemplated by this invention.

Referring now in detail to the drawings, the mine roof supporting bolt of this invention is shown, as a finished product, in Figure 6. The belt, indicated by the reference numeral ii is equipped with a threaded end H and a bifurcated end i2. Here it is to be noted that bolts designed for use in the above referred to method of supporting mine roofs are fabricated from rod stock of a diameter determined, to a great extent, by a type of thread employed. When out threads are used the usual diameter of the stock is 1". When rolled threads are used the usual diameter of the stock is only .907". Owing to the smaller cross sectional area of the rolled thread stock, the strength of this bolt at the end of the slot is critical.

Regardless of the type of thread employed it is the present practice to form the bifurcated end of the bolt by a slitting operation performed either with a suitable cutting tool or with an oxyacetylene torch. Either bifurcating method or means necessarily results in a removal or loss of some of the effective cross sectional area of the stock, the amount of such loss depending upon the width of the resulting slot formed in so bifurcating the stock. Experience has, however, shown that with these methods of bifurcating the stock a bolt of greater strength is produced if provided with rolled threads, the rolled thread type of bolt having been found in practice to have greater strength at the base of the rolled threads than a 1" diameter rod wtih cut threads. As a consequence, the practice of rolling the threads in producing the finished bolt is becoming generally widespread within the industry. However, bolts finished or produced in this manner are not without the disadvantage of being weakest at the end of the furcation when produced by present methods. When it is considered that these bolts are usually four or five feet in length, the loss of useful material resulting, as above mentioned, from the present day method of bifurcating or splitting the ends thereof is considerable. Also with these present day methods of bifurcating the rod in the production of the bolt the tendency of the bolt to break, either in the region of the threads, as is the case when out threads are employed, or in the region of the inner end of the slot or furcation, as is the case when rolled threads are employed, is ever present and constitutes the limiting factor in connection with their employment in mine roof supporting operations.

The end I2 of the bolt ill of this invention is bifurcated with a departure from the above described prior art methods of bifurcation, by shearing the stock subsequent to providing a notch E3 in the extremity of the end 12 of the bolt. I have found that by so forming the bifurcated end [2 of the bolt there is no loss of material whatever incidental to the shearing operation, and when the shearing operation is performed in a manner and with a machine embodying the features of this invention there results no permanent deformation in the cross sectional shape of the bolt, and the tendency of the bolt to break in the region of the inner end of the furcation is almost entirely eliminated. I have also found that a bolt produced in accordance with this invention may be fabricated from a higher carbon, higher strength, lower cost steel stock than has heretofore been possible with the present day method of producing these bolts. Thus a bolt bifurcated with the method and machine contemplated by this invention may be produced as a finished product with rolled threads as is now found desirable because, as above indicated, bolts so threaded lend themselves to greater mass production than do bolts equipped with cut threads. At the same time the finished product of this invention is a bolt that is free of those disadvantages above enumerated as being characteristic of the present day type of bolt employed in mine roof supporting and construction.

The machine contemplated by this invention whereby the method of this invention for bifurcating the rod stock to produce bolts having the above described desirable features of this invention, will be readily understood from the following detail description thereof. The machine as a complete unit is shown in Figure l, and the essential structural and functional characteristics of the machine are shown in Figures 2 to 5 inclusive. As therein illustrated the machine, indicated generally by the reference numeral I 4, is characterized by a stationary shear plate l5 removably mounted on the body It of the machine, being seated in a horizontal groove l1 and made secure therein in any suitable manner, and a complemental but vertically swingable shear plate 18 carried by an arm 19, and seated and removably secured within a groove 2i] provided therefor in said arm. When in the position of rest shown in Figures 1 and 2, shear plate i8 is yieldingly held slightly spaced from shear plate l5 by detents 2! that impinge upon arm I9 in a manner clearly shown in Figure 4. This permits ready initial engagement of the bolt rod stock 22 with the shear plates and equally ready removal of the rod and from the machine immediately following completion of the work in the manner contemplated by this invention. Arm I9 is provided with an integral split clamp portion 23 through the medium of which the arm is detachably secured to a pintle or stub shaft 24 journaled in a bearing 24a. that is preferably formed as an integral part of the body portion of the machine.

Vertical swinging movement of arm l9 to effect a shearing of bolt rod stock 22, in a manner hereinafter more fully explained, is imparted to the arm from a driven shaft 25 through the medium of a friction wheel drive 26, 21 between the shaft 25 and a crank shaft 28, a crank arm 29 connecting shaft 23 with the arm is (Figures 2, 4 and 5). In connection with the foregoing, it will be noted that shafts 25 and 28 are suitably iournaled in the body portion of the machine and that the latter is suitably hollowed out as indicated generally at 30 to accommodate the crank of shaft 28, the crank arm 29, the vertically swinging arm I9 and other elements hereinafter referred to.

It will also be understood that any suitable power means may be employed for driving the driven shaft 25. For purposes of illustration I have shown such means to consist of a suitable electric motor 3| and a belt and pulley drive connection 32 between the armature shaft of motor 3| and shaft 25 (see Figure 4). Also, if desired, and as shown, the friction wheel drive connection 26, 2! between shafts 25 and 28 are enclosed within a suitable housing 33 (see Figures 1 and 4).

Arm H) has limited lateral movement so as to provide for the adjacent faces of the shear plates l8 and I5 being in substantially close contact during the actual shearing operation. For imparting the desired movement of the shear plate l8 towards the shear plate l5 there is provided a shifting element in the form of a wedge 34 interposed between the arm [9 and a proximate portion of the body 15 of the machine. The Wedge 34 is guided in its vertical movement through the medium of, for example, a mortise connection 35 between the wedge and the referred to portion of the machine body [6 (see Figures 1 and 4).

Also, to reduce friction to a minimum, wedge 3:1 is provided with an oil plate 38 removably secured to the wedge by set screws or other fastening elements 31 (see Figure 4) Vertical movement of the wedge 34 in properly timed relation to the swinging movement of arm i9 is obtained through the medium of a cam disc 38 mounted on the shaft 28 to turn therewith and provided with a cam groove 39 in which is accommodated a roller 40 mounted on a pintle carried by an appendage or extension M of the Wedge 34 (see Figures 4 and 5). As also shown in these figures, crank arm 29 has a lost-motion connection with-arm l9, this connection consisting-of a pin 42 carried by depending lugs on the bottom of arm l9 and extending through a slot provided in the crank arm 29. The functional cooperation between the cam connection of shaft 28 and Wedge 34 and the lost-motion connection between the crank arm 29 and shear plate carrying arm [9 will be hereinafter shown in the detail description of operation of the machine.

Each shear plate I 5, I8, is formed with a longitudinal groove 43, semi-circular in cross section,

on its internal or working face, and provides straight parallel working edges. These grooves 43 are also of a depth that the bar stock 22 will extend for slightly less than half'of its cross sectional area-into each groove, snugly fitting within the groove, as shown to advantage in Figure 3. As a consequence withdrawal of the bar from the machine will not be possible following the splaying of the bar until shear plate It has returned to a position paralleling shear plate 15, or in other words until the two halves of the split bar are in parallelism, that is, the position shown in Figure 6. This ensures a complete restoration of the cross sectional shape of the bar with all the attendant advantages above set forth for the finished bolt as contemplated by this invention.

The operation of the machine may be briefly described as follows:

Normally the hump portion 39a of cam groove 39 is at the top of dead center so that normally the wedge 34 is in a position elevated with respect to that shown in Figure 4 of the drawings and arm I9 is in a laterally retracted position, but in the horizontal position shown in Figure 4. With the parts in the positions just mentioned, the end of the rod stock 22 to be bifurcated for forming the bifurcated end 12 of bolt it is then inserted into the machine in engagement with the grooves 42 of the shear plates. When the end of the bar has thus been engaged between the shear plates and crank shaft 28 is rotated, cam disc 38 will rotate moving the cam hump 39a out of engagement with the follower roller 40 resulting in a downward movement of wedge 34 to the position shown in Figure 4. This downward movement of the wedge causes arm Is to move laterally for bringing the face of shear plate l8 in close contact with the rod and close to the face of shear plate l5. Immediately following the placing of the plates l8, I5 nearly in facial contact, arm I 9 together with plate [5 will move downwardly in response to the pull exerted thereon by the crank arm 29, and as rotation of shaft 28 continues the end of the bar 22 will be split in half as shown in Figure 3. On the return stroke of the crank arm 29 arm l9 will be caused to move upwardly from the position shown in Figure 3 to the position shown in Figure 4, thus placing the two halves of the split end of the rod in close parallel contact. When the arm l9 returns to the position shown in Figure 4 the cam hump 39a will be substantially in the position shown in Figure 5, and as will be obvious, as shaft 28 continues to rotate the hump 39a moves into contact with the roller 46 causing the wedge M to move upwardly from the position shown in Figure 4 until the cam hump 39a is at top dead center. At that position of the cam hump arm i9 is free to-move laterally to a retracted position, and does so in response to the pressure exerted thereon by the detents 2|. The shear plates l8 and I5 are thereby separated sufficiently to permit the sheared end of the rod to be readily withdrawn. The parts are now in the position for repeating the operation just described on the next rod to be worked upon.

From the foregoing it will be seen that the shearing of the rod and the return of the two halves of the sheared rod to close parallel contact are accomplished without loss of any of the material of the rod stock and without any deformation in the original cross sectional shape of the rod. I i I While the invention has been described in detail in its presently preferred embodiment, it will, of course, be understood that such has been done for purposes of illustration only and not by way of limitation, and therefore only such limitations are to be imposed thereon as may reasonably come within the scope of the appended claims.

I claim:

1. A machine for splitting metal rods in the production of mine roof supporting bolts, comprising a pair of adjacent shear plates having parallelly arranged working faces, each of said plates having opposed, straight semi-cylindrical grooves formed in the working faces thereof to snuglyfit the metal rod, means supporting one of the plates in fixed position, means for pivotally mounting the other plate on an axis perpendicular to the axis of said grooves for swinging movement relative to the first plate, said movable plate being shiftable on said axis to permit movement of the movable plate relative to the fixed plate at the beginning and end of each shearing operation, yieldable detents acting in opposition on the pivotally supported plate for normally holding the plates separated, means for urging the plates into close contact with one another during vertical swinging 0f the pivotally supported plate, and driven means connected with the movable plate and'the urging means for sliding the latter into and out of engagement with the movable plate in predetermined timed relationship, the grooves actin to displace a portion of a bolt during the movement of the movable plate and to return the displaced portion to its initial position.

2. A machine for splitting the ends of metal bolts comprising a fixed shear plate having a working face, a movable shear plate including a working face opposed to and substantially parallel with the working face of said fixed plate, said movable shear plate being pivotally mounted on an axis perpendicular to said working faces and shiftable on said mounting for movement toward and away from the fixed plate, a shiftable wedge engageable with the fixed plate to move the latter into close engagement with the fixed plate, yieldable means acting on the movable plate in opposition to said wedge and driving means connected with the movable plate and the wedge for swinging the movable plate relative to the fixed plate and for sliding the wedge into and out of engagement with the movable plate in predetermined timed relationship, the working faces acting to displace a portion of a bolt during the movement of the movable plate and to return the displaced portion to its initial position.

3. A machine for splitting metal rods comprising a fixed shear plate having a working face, a movable shear plate including a working face opposed to and substantially parallel with the working face of said fixed plate, said faces being provided with opposed straight, semi-cylindrical grooves to snugly fit the metal rod, said movable shear plate pivotally mounted on an axis perpendicular to the axis of said grooves and shiftable on said mounting for movement toward and away from the fixed plate, means including a power element operatively connected to the movable plate for actuating the latter so that a bolt contained in the grooves of said plates is sheared on its longitudinal axis and thereafter reshaped to its original form, and means for effecting a lateral pressure including a shifting member connected to said power element, the last said means being coordinated with the first means, so that lateral pressure is applied to the movable plate during the shearing and re-forming operations and relieved thereafter.

4. A machine for splitting the ends of metal bolts, comprising a fixed shear plate having a working face, a movable shear plate having a working face mounted adjacent to and substantially parallel with the working face of said fixed plate, said plates having opposed straight, semicylindrical grooves formed on the working faces thereof to snugly fit the metal rod, said movable shear plate pivotally mounted on an axis perpendicular to the axis of said grooves and shiftable on said mounting for movement toward and away from the fixed plate, a shiftable wedge engageable with the movable plate to move the lat.- ter into close engagement with the fixed plate,

yieldable detents acting on the movable plate in opposition to said wedge, and driven means connected with the movable plate and the wedge for swinging the movable plate relative to the fixed plate and for sliding the wedge into and out of engagement with the movable plate in predetermined timed relationship, the grooves acting to displace a portion of a bolt during the movement of the movable plate and to return the displaced portion to its initial position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 153,142 Wilson July 14, 1874 340,683 Smith Apr. 27, 1886 747,219 Preslar Dec. 15, 1903 901,667 Wrigley Oct. 20, 1908 1,131,343 Dodds Mar. 9, 1915 1,220,024 Tanzi Mar. 20, 1917 1,422,274 Johnson et a1. July 11, 1922 1,511,952 Donahoo Oct. 14, 1924 1,563,965 Christianson Dec. 1, 1925 1,638,483 Giandohato Aug. 9, 1927 1,727,698 Clouse Sept. 10, 1927 1,836,712 Hallden Dec. 15, 1931 1,876,174 Stoler Sept. 6, 1932 FOREIGN PATENTS Number Country Date 75,304 Germany May 25, 1894

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