US3202368A

US3202368A - Single rotor crusher

Info

Publication number: US3202368A
Application number: US305025A
Authority: US
Inventors: Virgil H Nixon
Original assignee: MISSOURI ROGERS CORP
Current assignee: MISSOURI ROGERS CORP
Priority date: 1963-08-26
Filing date: 1963-08-26
Publication date: 1965-08-24
Anticipated expiration: 1982-08-24
Also published as: US3295773A

Description

Aug. 24, 1965 v. H. NIXON SINGLE ROTOR GRUSHER 3 Sheets-Sheet 1 Original Filed Aug. 51, 1959 l lu p INVENTOR. VIRGIL H. NIXON M4 gala 4&4,

ATTORNEY* Aug. 24, 1965 v. H. NIXON 3,202,368

SINGLE ROTOR CRUSHER Original Filed Aug. 31, 1959 3 Sheets-Sheet 2 INVENTOR. VIRGIL H. NIXON ATTORNEY 4, 1965 v. H. NIXON 3,202,368

S I NGLE ROTOR CRUSHER Original Filed Aug. 31, 1959 3 Sheets-Sheet 5 INVENTOR. VIRGIL H. NIXON jiww ATTORNEY United States Patent 3,292,368 SINGLE ROTUR CRUSHER Virgil H. Nixon, Joplin, Mo assignor to Missouri-Rogers Corporation, Joplin, Mo., a corporation of Missouri Continuation of application Ser. No. 837,053, 'Aug. 31, 1959. This application Aug. 26, 1963, Ser. No. 305,025 2e Claims. (Cl. 24'1189) This invention relates generally to crushers, and more particularly to impact type single-rotor crushers; and this application is a continuation of my prior application Serial No. 837,053, filed August 31, 1959, now abandoned.

Among the several objects of the invention will be noted the provision of a single-rotor crusher of rugged economical construction; the provision of a crusher having breaker bars arranged for both primary and secondary crushing; the provision of a crusher wherein certain breaker bars are adjustable yet are adapted to yield in the event of a jam but without danger to adjacent personel or machinery; and the provision of a crusher having improved breaker action.

Although the apparatus will be described in detail in connection with the drawings, briefly, the crusher of this invention comprises a housing with side, back and top walls defining a front feed entrance and a bottom discharge opening. Breaker bars extend horizontally between the side walls in parallel vertically-spaced relationship adjacent the top and back wall, there being a space between the breaker bars and back wall through which the reduced product may pass. The breaker bars in the upper portions of the machine are in relatively fixed positions and are conveniently mounted merely in openings cut in the side walls through which the bar ends project, the bars then being held against endwise displacement, as by collars or by elongate plates which are bolted to the outer surface of the side walls. Adjustable breaker bars are mounted in the back lower part of the machine horizontally opposite an inclined feed plate at the front of the machine, and the rotor is arranged so as to project above the line between the lower adjustable bar and the lower part of the feed plate.

In mounting the adjustable bars, horizontal slots are cut through the side walls to accommodate the bar ends, and U-shaped brackets are fastened to the side walls so that the legs of a bracket extend rearwardly above and below the adjacent slot. The end of a breaker bar is then held between a pair of support blocks suitably re cessed to embrace the end of the bar, and the blocks are *slidably mounted between the bracket legs.

Each bar-supporting block is backed up by a set of shims, the front set being held by a lock-bolt threaded through the front of the bracket and the back set of shims being held by a plate or block hinged on a pivot pin in the back of the bracket. This back plate is releasably secured by a shear pin, but can swing back when the shear pin breaks, as might occur during a jam. The breaker bars are adjusted toward or away from the rotor by adding or removing shims. It will be apparent, however, that the likelihood of flying parts is minimized. In fact, it is desirable to provide a cover plate supported from the pivot pin to extend forwardly over the shims, the front of the cover having an inturned lip secured by the lock bolt.

The rotor is a solid somewhat cylindric member actually having the exterior shape produced if a true cylinder were slit along a diameter and the two parts then shifted port a narrow hammer plate, which has an inner front beveled corner and an inner back lip. The back lip fits within a suitable dove-tail groove in the inner back part of the hammer-receiving slot of the rotor, while a wedge element fits within a dove-tail groove in the forward part of the hammer slot, with the result that the hammer plate is securely locked within the rotor. If desired, the hammer plate may also be secured by bolts extending peripherally through the plate and rotor.

The wedge system involves a pair of axially movable Wedge parts adapted to be drawn toward one another on a rod extending lengthwise of the rotor adjacent the inner front portion of the hammer plate. Each end of the rod is threaded to receive a nut for forcing the wedges to ward one another, and these threaded ends are further slit and axially tapped to accommodate a locking plug, which tends to expand the bifurcated ends of the draw rod against the nut.

A further feature of the invention is the provision of a readily removable breaker bar mounted in the lower 'part of the rotor. With this arrangement, the machine is adaptable for both primary and secondary crushing, the removable bar being drawn out for primary crushing and being inserted for secondary crushing. The remov able bar fits within holes in the side walls and is secured by a removable end cover plate fastened to the exterior side walls.

The side walls of the machine are constructed in separable sections of diminishing thickness in the upward direction, thereby providing economy and wear resistance. The separable sections also permit the top to be lowered for secondary crushing.

Other features of the invention will be in part apparent from and in part pointed out in the following detail description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a side elevation of a crusher embodying the invention;

FIGURE 2 is a front elevation of the crusher shown in FIGURE 1;

FIGURE 3 is a vertical section through the crusher;

FIGURE 4 is an exploded perspective view of the by triangular gusset plates 7 fastened to horizontal plates 9, which rest upon the side base members 1. The discharge chamber at the lower end of the crusher is defined by a pair of inclined front and back plates 11 which span the space between the side plates 5 and are secured thereto. The rotor bearings 13 are suitably supported 'upon the longitudinal base members 1, as by pillow blocks The side walls of the housing are further defined by intermediate plates 17 resting upon the lower plates 5 and secured by strips 6. Upper plates 19 secured by strips 8 complete the side Walls. A back wall 21 fastened between the side wall sections 17 extends upwardly from the back discharge plate 11, and top-forming walls 23 fastened between side sections 19 extend across the back upper portion of the housing. The front 25 of the housing is opened for entry of the rock, and an open front hood 27 is mounted on the upper front portion of the housing so as to provide a larger feed entrance. It will be noted in FIGURE 2 that the thickness of the side 7 wall plates diminishes in the upward direction, hence the side wall structure formed from a multiplicity of side plates is advantageous in achieving an economical construction consistent with the strength requirements of a crusher, wherein the greater wear is at the lower portion adjacent the rotor. Also, the several side sections permit adjustment in the height of the machine, as by replacement of side sections at the upper part of the machine. Chains 29 may be hung from the top of the hood 27, as illustrated in FIGURE 2, the rock being fed between the lower ends of the chains and the top of an inclined feed plate or chute 31. The chains permit large rock to enter the machine while preventing the smaller rocks from being thrown outwardly during the crushing operation.

V The location' of the feed plate 31 with respect to the rotor and the primary breaker bars is important. The relative location is such that, in normal operation, only one hammer of the rotor is working at any instant. Working is here used in the sense of delivering blows upon the stone to be crushed; it being understood that both hammers constantly (while in rotation) contribute their mass to the energy which either hammer can deliver. This is accomplished by arranging the breaker bar, which. determines the maximum size of the crushed product, at an angular displacement (about the axis of the rotor) from the feed plate which is sufficiently less than the angular displacement between successive hammers that, in each revolution, the work of one hammer is completed before the work of the succeeding hammer commences. Thus the whole energy potential of the rotor is concentrated in one hammer which at the instant is active, i.e., in motion from a point adjacent the termi nus of the feed plate toward said breaker bar; and such energy potential does not suffer reduction through expenditure of energy by another hammer at the same instant. The top of the feed plate may be from thirty to forty-five inches above the axis of the rotor, depending .upon the size of the crusher, and the plate inclines downwardly close to the periphery of the rotor at an angle such as to intersect with a point slightly above the axis of the rotor. The horizontal distance between the axis of. the rotor and the front edge of the feed plate might be three to five feet, depending upon the size of the crusher. Also, the space below the inner edge of the feed plate .may be closed off with a plate 33 extending between the side walls of the housing, the plate 33 extending from the inner edge of the feed plate 31 forwardly and downwardly at approximately a right angle withrespect to the feed plate and terminating adjacent the upper edge of thefront discharge plate 11.

The rock is thrown by the rotor against horizontal breaker bars mounted in spaced parallel relationship to span the side walls of the housing adjacent the top and back walls of the machine, but in spaced relationship from the walls, thereby to provide a chute for the small product to fall into the discharge outlet. The upper breaker bars 35 are fixed within the machine at predetermined positions. In accordance with this invention, the breaker bars 35 are rod-like members which extend through slightly larger openings in the

side plates

17 and 19. The breaker bars are of a length such that they project into the side walls and are thereby held directly by a the side walls, but the portion of a bar between the side walls may support a hardened Wear sleeve. End closure plates 37 are shown to be bolted, or otherwise fastened, to the outer surfaces of the side walls to prevent endwise displacement of the breaker bars.

It will be noted that the upper fixed breaker bars 35 extend downwardly to a line opposite the upper front portion of the feed plate 31. A pair of relatively adjustable breaker bars 39 with wear sleeves 36 are then mounted in the space horizontally opposite from the feed plate 31, and these breaker bars 39 are also mounted so as to have a shear-pin releasing action, thereby avoiding damage in the event that an unduly large and hard rock, or other item, tends to be jammed between the rotor and lower breaker bars 39.

The explosion chamber of the crusher is defined by

side plates

17 and 19, front 25, and breaker bars 35 and 39. In the condition shown in the drawing, the lower one of bars 39, being closer to the axis of the rotor, controls the maximum size of product which can pass from the explosion chamber to the discharge chamber; it being noted in this connection that there is greater clearance between the lower bar 39 and most of the peripheral surface of the rotor than there is between the breaker bars above it. When a substantial amount of large size product is desired, the lower one of bars 39 may be retracted or omitted, thereby to cause the upper one of bars 39 to become the control bar and provide clearance for the passage into the discharge chamber of larger pieces of rock.

The manner of supporting the adjustable breaker bars is one of the features of this invention. A generally horizontally elongate slot 41 is cut in each side plate 17 for each breaker bar 39, and a U-shaped stirrup bracket is then fastened to the side wall so that the legs 43 of the stirrup or bracket project rearwardly on opposite sides of the slot. The bracket opens in the rearward direction and is closed by a front plate 45. The breaker bar 39 is then held within a bearing-like block or blocks 47 which are horizontally movable between the legs 43 of the stirrup. The blocks 47, in turn, are adjustable horizontally by means of shims 49 backing up the breakersupporting blocks both at the front and back thereof. The front set of shims is held by a lock bolt 50 which extends through a threaded opening 51 in the front closure wall 41 of the bracket, whereas the back set of shims is held by a pivotally-supported shear-pin block 53. It will be noted that the back portions 55 of the stirrup bracket project outwardly from the side wall of the housng so as to support a pivot pin 57 in spaced relationship from the side wall. The shear-pin block then extends inwardly from the pivot pin 57 at right angles to the side wall so as to hold the back shim 47, and is itself secured by an inner shear-pin 59. A keeper plate 61 may hold both the pivot pin and shear-pin within the stump bracket. Finally, a cover plate 63 is also secured upon the pivot pin 57 to extend forwardly over the shims 49 and supporting blocks 47. An inwardly directed fiangefis extends from the front of the cover plate within the stirrup bracket and is secured by the lock bolt 50, there being a suitably large aperture 67 in the flange 65 through which the lock bolt may project.

The advantage with this arrangement is that it not only permits adjustment of the breaker bar positions by removmg or adding shims, but also protects the apparatus by releasing the breaker bar through rupture of the shear pin, and further encloses the flying parts so that bystanders or adjacent equipment will not be injured. The forces developed when a shear pin breaks are so great that the parts tend to fly outwardly at considerable velocity, and could injure or damage personnel or equipment nearby, if not secured to the crusher or suitably enclosed.

The crusher of this invention further includes another breaker bar 71 mounted slightly below the horizontal axis of the rotor, which breaker bar 71 is removable, so as to permit the crusher to be used for both primary and secondary crushing. The bar 71 is removed during primary crushing, and is inserted for secondary crushing or reduction of the rock to relatively small size. During such secondary crushing, the bar 71 serves essentially to prevent .the passage to discharge 11 of oversize material which passed bar 39 with less than its maximum dimension oriented radially .to the rotor, but whose maximum dimension (if so oriented) would have been reduced at bar 39. In

such cases, enough reduction occurs between bars 39 and 71 to permit the fragments to escape to discharge 11 the time) and bar 71. Otherwise, the bar 71 contributes to the function of bars 73, now to be described. Deflector bars 73 may be located below the bar 71 in such position as to form a screen, and prevent rock from being thrown downward under force of such magnitude as to damage whatever is below it. The breaker bar 71 is secured in the same fashion as the breaker bars 35, there being an end plate 75 which is bolted to the side wall 5 to prevent endwise displacement, the bar otherwise being held by projecting into, or through close-fitting openings in, the side wall plates 5.

The rotor shaft 81 is supported in the bearings 13, and the rotor 83 is a solid casting which is secured on, and keyed to, the shaft. Rotor rings 85 may be attached to the ends of the rotor itself. Although the rotor is a solid casting with weight-reducing holes 84, it is not truly cylindric, but rather has a shape that would be produced if a cylinder were sliced diametrically, and the two halves slipped on the diameter so as to provide radial faces or shoulders 87 on opposite sides. The hammers 89 are then secured against the shoulders 87.

Each hammer is an elongate narrow plate of hard-wearing material, but the inner edge thereof is specially shaped to lock within a slot 90 extending lengthwise across the rotor in front of a shoulder 87. A bevel 91 is formed along the inner front face of the hammer for cooperation with certain wedge members fitting within the front part of slot 90. The inner back portion of the hammer has a rearwardly projecting lip 93, which is locked or received within a dove-tail portion 94 in the back part of the hammersupporting slot 90.

The wedge members force the lip rearwardly into the rotor so as to lock it against radial displacement. In addition, bolts 95 may extend through the hammer and rotor so as to provide a further means of securing the hammer, but the wedge and lip lock is the primary means of holding the hammer within the rotor.

The wedge elements are accommodated within a dovetail groove 97 extending across the front of slot 90, and the rotor end rings 85 are also cut away at opposite the ends of this slot 90 so as to permit adjustment of the wedge action. A pair of elongate tapering wedge elements 99 telescope over the draw rod 101, and each wedge element is shaped so as to have larger cross-sections in the direction outwardly or endwise of the rotor. When the wedge elements 99 are then drawn toward one another on the draw rod, they wedge the hammer firmly within the rotor. One end of the draw rod 101 is threaded to receive a nut 103 by means of which the wedges are drawn inwardly. -It is desirable, however, to provide a locking arrangement for the nut 103, and such a lock is conveniently provided by slitting the threaded end 165 of the draw rod, and by providing a tapped hole in the end of the rod for accommodating a pipe plug 107 (FIG. 6). After adjustment of the nut 103, the pipe plug 107 is screwed in to expand the bifurcated ends of the rod and lock the nut 103 securely thereon against loosening under the forces of vibration.

From the foregoing description, it is apparent that those skilled in the art will understand the structure, function and mode of operation of the invention herein disclosed, and appreciate the advantages thereof. Although one embodiment has been displosed in detail, it is to be understood that the invention is not limited thereto, but the drawings and description thereof are to be understood as being merely illustrative.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In a crusher of the type having a rotor, an opent'ront housing, and a series of horizontal breaker bars in vertically spaced relationship adjacent the back of the housing; the improvement that comprises at least one of said bars being readily deactivated and another of said bars being adjustable toward and away from the rotor, said readily deactivatable bar being below said adjustable bar distance greater than the space between the bars of said series, thereby to permit both primary and secondary crushing within the rotor by removal of the lower bar and adjustment of said other breaker bar.

2. In a crusher of the character having a housing, the housing having side walls and generally horizontal breaker bars spanning the side walls; the improvement that comprises one of said breaker bars being of a length such that the ends thereof extend into the side walls, the side walls per se having holes cut therein of a size closely fitting with the ends of said breaker bar, thereby to hold the bar and removable means fastened to the exterior surfaces of side walls preventing endwise displacement of the breaker bar.

3. A crusher as set forth in claim 2, further including a wear sleeve telescoped over said breaker bar, said wear sleeve being of a length and diameter such that its ends abut against the inner surfaces of said side walls.

4. In a crusher of the character having a housing in which a rotor and cooperating breaker bar are mounted, the improvement that comprises bar-supporting means for holding the breaker bar at its ends, the bar-supporting means being mounted on the exterior of the housing for sliding movement toward and away from the rotor, slots in the housing through which the bar extends to the movable supporting means, a back-up element pivotally mounted on the housing for limited movement between predetermined positions toward and away from the rotor, and a shear-pin mounted on the housing for normally holding said back-up element in its position toward the rotor, and shim means interposed between the back-up member and bar-supporting means.

5. In a crusher of the character having a housing at which a rotor and cooperating breaker bar are mounted, the improvement that comprises said housing having openings in opposite sides thereof to accommodate the ends of the breaker bar, said openings being of a size and shape such as to permit limited movement of the breaker bar toward and away from the rotor with the ends of the breaker bar projecting through said openings, a generally U-shaped bracket mounted on the housing on each side thereof so that the legs of the bracket extend on opposite sides of the opening in the direction away from the rotor, bar-supporting means slidably contained between said legs of the bracket for movement toward and away from the rotor, a back-up element secured between the open ends of the bracket, and a set of shims interposed between the back-up element and bar-supporting means.

6. Apparatus as set forth in claim 5, wherein said backup element is pivotally supported upon said bracket for swinging movement from an initial position closing the end of the bracket to a position clear of the end of the bracket, said back-up element being held in its initial position by means of a shear pin. 7

7. Apparatus as set forth in claim 6 further including a set of shims interposed between the back-up element and bar-supporting means.

8. Apparatus as set forth in claim 7, further including a cover plate pivotally supported on said bracket and extending over said shims and bar-supporting means, thereby to confine said shims and bar-supporting means within said bracket.

9. Apparatus as set forth in claim 8, furtherincluding a lock bolt extending through the closed end of the bracket adjacent the rotor, said cover plate having an end portion releasably held by a lock bolt.

10. In a crusher of the character having a housing at which a rotor and cooperating bracket bar are mounted, the improvement that comprises said housing having openings in opposite sides thereof to accommodate the ends of the breaker bar, said openings being of a size and shape such as to permit limited movement of the breaker bar toward and away from the rotor with the ends of the breaker bar projecting through said openings, bracket means having legs mounted on each side of the housing so that the legs of the bracket'extend on opposite sides of the opening in the direction away from the rotor,

7 bar-supporting means slidably contained between said legs of the bracket for movement toward and away from the rotor, a back-up element secured between the open ends of the bracket, and a .set of shims interposed between the back-up element and bar-supporting means.

11. In a single rotor impact crusher having two hammers fixedly mounted on the rotor in 180 displacement, a feed chute at one side of said rotor, and a vertically extending series of stationary breaker elements at the other side of and above the axis of said rotor, said breaker elements being spaced apart a distance less than a given value, a lower member of said series being spaced from the axis of said rotor a distance greater than the minimum radius of said rotor plus said given value and at least as great as the maximum radius of the hammers on said rotor, said lower member being the one of the series'which is closest to the axis of said rotor, said chute having its terminus adjacent the orbit of the outer periphery of said hammers in the quadrant of said orbit ahead of its zenith, said lower member of said series being located in the quadrant of said orbit behind its zenith, and the angle (about the axis of said rotor) between said chute terminus and said lower member being sufiiciently less than 180 that during each revolution one hammer is substantially idle when the other reaches the terminus of the chute. 12. Ina single rotor impact crusher having only two hammers fixed relative to the rotor, a series of breaker bars mounted above the axis of said rotor to interrupt the flight of material hurled upwardly and laterally by said rotor, the one of said bars which is nearest the rotors orbit being located near a tangent to the zenith of the rotors orbit, and shim means for adjusting the displace ment between said one of said bars and the rotors orbit to vary the maximum size of the product which can pass below said bar.

13. The crusher of claim 12 wherein below said one of said bars there is a screen defined at its upper end by an auxiliary breaker bar spaced from said one of said bars a distance sufficient to provide an escape for substantially all material which passes between said one bar and said rotor.

14. The crusher of claim 12 wherein said shims are provided with overload release means.

15. An impact crusher comprising in combination: a housing having an inlet opening at the upper portion thereof and a discharge opening at the bottom thereof;

a single rotor journalled above said discharge opening and having no more than two axially extending harnmers mounted, respectively, at diametrically opposite positions thereon, said hammers having peripheral surfaces which constitute the maximum radius of the rotor and which when rotated describe a hammer circle; a downwardly and inwardly inclined feed chute extending from a wall of said housing adjacent said inlet opening toward said hammer circle in a direction such that the upper surface of said chute, projected, intersects with the hammer circle at a point above the axis of the rotor; means for driving said rotor in a direction such that, when in rotation, each hammer passes said point during the ascending portion of its orbit; and a series of spaced breaker elements mounted in said housing near but substantially spaced from the side thereof toward which said hammer moves in the upper portion of its orbit, the member of said series which is closest to said hammer circle being on a radius of said hammer circle that is less than 180 degrees from said point in the direction of rotor rotation.

16. The crusher of claim 15 wherein said feed chute slopes at an angle of about forty-five degrees with the horizontal and is so positioned that the upper surface thereof projected lies above the diameter of said hammer circle with which it is parallel.

17. The crusher of claim 15 wherein said closest one of said breaker bars is disposed, in part at least, below the upper horizontal tangent to said hammer circle.

18. A single-rotor primary crusher comprising a housing, a single rotor journalled within the housing in a position such as to provide an explosion chamber of substantial size above the rotor and a discharge chamber below the rotor, a hammer projecting from the rotor, a feed chute inclined downwardly and inwardly towards the rotor, the feed chute being disposed on one side of the vertical plane through the rotor axis to feed rock into the path of the hammer at a level above that of the rotor axis and below the level of the top of the hammer path, whereby rock so fed is impelled by the hammer upwardly through said explosion chamber to a region therein on the side of said vertical plane opposite said chute, a series of rugged breaker members in said region and arranged to intercept the flight of rock impelled by said hammer, said series of breaker members including at its lower end a control breaker member spaced from the hammer path but closer thereto than the other members of the series, the spacing of said control breaker member from the hammer path controlling the maximum size of product which can pass intact from the explosion chamber to the discharge chamber, and said control breaker member being located vertically, at least in substantial part, between the level of the rotor axis and the level of the zenith of the hammer path.

19, A crusher as set forth in claim 18, wherein said control breaker member is adjustable toward and away from the rotor, thereby to vary the maximum product size.

29. In a single rotor impact crusher having hammers fixedly mounted on the rotor, a feed chute at one side of said rotor, and a vertically extending series of stationary breaker elements at the other side of and above the axis of said rotor, said breaker elements being spaced apart a distance less than a given value, a lower member of said series being spaced from the axis of said rotor at distance greater than the minimum radius of said rotor plus said given value and at least as great as the maximum radius of the hammers on said rotor, said lower member being the one of the series which is closest to the axis of said rotor, said chute having its terminus adjacent the orbit of the outer periphery of said hammers in the quadrant of said orbit ahead of its zenith, said lower member of said series being located in the quadrant of said orbit behind its zenith, and the angle (about the axis of said rotor) betweensaid chute terminus and said lower member being suiiiciently less'than the angle between successive hammers on the rotor that during each revolution one hammer is substantially idle when the other reaches the terminus of the chute, a radial escape below said lower member, said escape being of magnitude such as to pass material which passed between said lower member and said rotor, and said escape being at least as great as said given value.

References Cited by the Examiner UNITED STATES PATENTS 2,463,223 3/49 Verch 241--189 X 2,618,438 11/52 Chrystal 241189 X J. SPENCER OVERHOLSER, Primary Examiner.

Claims

1. IN A CRUSHER OF THE TYPE HAVING A ROTOR, AN OPENFRONT HOUSING, AND A SERIES OF HORIZONTAL BREAKER BARS IN VERTICALLY SPACED RELATIONSHIP ADJACENT THE BACK OF THE HOUSING; THE IMPROVEMENT THAT COMPRISES AT LEAST ONE OF SAID BARS BEING READILY DEACTIVATED AND ANOTHER OF SAID BARS BEING ADJUSTABLE TOWARD AND AWAY FROM THE ROTOR, SAID READILY DEACTIVABLE BAR BEING BELOW SAID ADJUSTABLE BAR DISTANCE GREATER THAN THE SPACE BETWEEN THE BARS OF SAID SERIES, THEREBY TO PERMIT BOTH PRIMARY AND SECONDARY CRUSHING WITHIN THE ROTOR BY REMOVAL OF THE LOWER BAR AND ADJUSTMENT OF SAID OTHER BREAKER BAR.