US1390839A - Crushing-mill - Google Patents

Description

T. J. STURTEVANT.

CRUSHING MILL.

APPLICATION FILED MAY. m9.

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CRUSHING MILL.

APPLlCATlON FILED MAY 1, 1919.

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APPLICATION FILED MAY 1. 1.919.

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CRUSHING MILL.

APPLICATION mm MAY 1. 1919.

Patented Sept. '13, 1921.

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T. J. STURTEVANT.

CRUSHING MILL.

APPLICATION FILED MAY 1, 1919.

Patented Sept. 13, 1921.

6 SHEETS-SHEET 6.

. folk and State UNITED STATES P ATENT OFFICE.

THOMAS J. SIURTEVANT, OF WELLES L EY, MASSACHUSETTS, ASSIGNOR TO STURTE- VANT MILL COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSA- CHUSETTS.

cRUsHINe-MILL.

Patented Sept. 13, 1921.

Application filed May 1, 1919. Serial No. 293,906.

To all whom it may concern:

Be it known that I, THOMAS J. STURTE- VANT, a citizen of the United States, residing at Wellesley, in the county of Norof Massachusetts, have invented an' Improvement in Crushing-Mills, of which the following description, in connection with the accompanying drawings, is a specification, like characters 011 the drawings representing like parts.

The invention to be hereinafter described relates to mills for crushin or reducing materials, and more particulln'ly to mills of the ring roll type.

Heretof'ore a mill employed comprising aifixed ringhaving an internal crushing surface, and a plurality of rolls which are carried by a head and revolved with a planetary motion to crush materials introduced between them. It has been customary to introduce the material to be reduced to the ring at one point, and thus the rolls in the course of their orbit progressively act on the material to crush the same. As a consequence, the rolls will progressively act on material of varying size, and the character of crushing effect of the different rolls will vary. One of the purposes of the present invention is to provide improved, simple and efiicient means to feed the materials a) be reduced in a plurality of streams simultaneously in front of the crushing rolls, the construction being such that the rolls act simultaneously on materials of substantially the same gradeland character. For example, if four rolls are employed, each will act on a stream of material introduced in front of it, and all four rolls will simultaneously share in the initial reduction of the materials, and will continue to share in the reductionof the materials. As aresult, the materials may be rapidly and efficiently reduced, less material may escape laterally from the crushing surface of the ring without being reduced, and the amount of tailings required to be returned to the mill for further reduction is materially reduced.

When the machine is at rest, the lower rolls rest upon and are supported by the lower arc of the crushing ring, whereas, gravity tends to lower the upper rolls down away from the ring. When the revolution of the rolls l commences, the speedis not sufficient todeof this type has been nism for the purposes of inspection,

upper arc ofthe crushing velop a centrifugal force which will overcome the efiect of gravity and consequently in the course of the revolution, the rolls, in passing abovea horizontal plane cutting the axis of. the ring, would move inward toward said axis; whereas, in passing beneath said plane, they would move outward toward and to the ring. The alternate inward and outward movement of the heavy rolls would be liable to injure the rotaryl mechanism carrying the rolls and would cause the rolls to pound against the ring.-

Another purpose of the invention, therefore, is to provide improved means to hold the rolls out against the ring so that such inward and outward injurious movements of the rolls are prevented.

In the course of the revolution .of the rolls, gravity will assist the crushing effect of the rolls traveling along the lower are of the ring, and will tend to reduce the crushing effect of the rolls traveling along the upper arc of the ring, and at times one of the rolls may encounter material of harder or larger character than the material encountered by the other rolls, thereby increasing the burden on' such roll and tending to destroy uniform operation of the rolls. Another purpose of the invention is to provide simple and efiicient operative connections between the rolls which will automatically tend to equalize the crushin effect thereof, and tend to maintain equal pressures of the rolls against the ring.

Mills of this type are called upon to perform heavy duty, and therefore, it is de sirable that prompt convenient access may be had .to the various parts of the mecha adjust ment and repair. Another purpose of the invention is to provide the casing for the a mechanism with doors which may be easily and quickly opened and allow ready access to all of the parts of the mechanism.

Another purpose of the invention is to provide simple and efficient means for lubricating the rolls and other parts of the mechanism.

And still another object of the invention is to provide strong and efficient means for carrying and revolving the rolls with a planetary motion.

\Vith the aforesaid and other objects in view, the character of the invention will be best understood by reference to the followthrust bearings details of one of the end for the roll head carrying shaft Y Fig. 6 is a plan view showing the doors of the casing in open position;

Fig. 6 is a horizontal section through one of the roll rock shafts and the clamping sleeve therefor showing the scuff angle of the rock shaft with respect to said sleeve;

Fig. 7 is a view partly in elevation and partly in section of the centrifugal feeder and the head carrying the crushing rolls;

Fig. 8 on an enlarged scale is a section taken on line 8-8 of Fig. 7

Fig. 9on an enlarged scale is a view partly inelevation and partly in section of one of the crushing rolls and the carrying shaft therefor;

Fig. 10 is a face view of the oil conducting thrust disk for one of the rolls;

Fig. 11 is an endelevation looking toward (the right of Fig. 9;

Fig. 12 is a perspective view of aportion of the hub. of one of the rolls, a part of the hub being brokenaway to disclose a lubricating device therein; and

Fig. 13 is a perspective view of the yoke forthe rock shaft of one of the rolls.

Referring to the drawings, the machine shown thereinas one practical form of the invention, comprises a bed (Figs. 1, 2, and 3) having a pair of parallel spaced base members 1. Mounted on said base members is a heavy ring 3 having brackets 4 resting on the tops of said base members and secured thereto by suitable bolts 7. A crusher ring 5 is'mounted in the ring 3 and has a tapered periphery 8 to fit a similarly tapered inner'surface of the ring 3. A pair of liner rings 9 are located at opposite sides of the crusher ring,and through bolts 11 are entered through registering holes in the heavy ring 3, the crusher ring 5 and the liner rings 9,.the construction being such that the crusher ring 5 may be drawn into the heavy ring 3 witha tight friction fit, and the liner rings may be held in proper relation with respect to the crusher ring 5. The liner ring at the leftof the crusher ring (Fig. 3) engages a circumferential shoulder 13 formed on the heavy ring 3 and is spaced somewhat from the crusher ring so as not to interfere with the adjustment of the crusher ring into tight engagement with the tapered surface of the heavy ring 3. The crusher ring has an internal crushing surface 15 which may have a slight transverse curvature to conform to the curvature of the crushing rolls, as more fully hereinafter described, and the liner rings may project somewhat beyond the crushing surface 15 to form a trough to retard somewhat the escape of materials from the crushing ring.

Any suitable number of crushing rolls may be provided to cooperate with the crushing ring in the reduction of material fed between them. In the present instance of the invention, four rolls 17 are provided and are adapted to move outward under the influence of centrifugal force to exert a crushing pressure against the crushing ring. Suitable carriers may be provided for the rolls to admit such movement thereof, and in the present instance of the invention, swing carriers are provided fulcrumed on and carried by a rotary head 19, more fully hereinafter described.

Since the carriers for the rolls are similar, a description of one will suffice for all. Each of these carriers, in the present instance of the invention, is in the form of a rock shaft 21 (Figs. 3 and 9) having a bushing 23 secured thereon by a pin 25 and on which the hub 27 of the roll 17 is rotatably mounted.

As stated, one of the purposes of the invention is to provide simple and efiicient means for lubricating the roll. To accomplish this, the rock shaft 21 is provided with a central longitudinal passage 29 (Fig. 9) normally closed by a plug 31 threaded in one end thereof. When this plug is removed, a supply of lubricant may be introduced into the passage 29. .To limit inward movement of the roll on its shaft and to conduct the lubricant from the passage 29 to the inner surface of the roll hub, a thrust disk 33 (Figs. 9, 10 and 12) may be provided having radial grooves 35 therein opposed to a thrust plug or collar 37 having a neck 39 projecting into a counter bore in the rock shaft and secured thereto by a key 41. It is desirable that this grooved disk shall rotate with the crushing roll, in order that centrifugal force may cause the lubricant to feed outiwird through the disk grooves 35. Suitable means may be provided to connect said disk with the hub of the roll for this purpose. To accomplish this, in the present instance, the hub of the roll is provided with an internal flange 43 (Figs. 9 and 12) formed to receive an hexagonal member 45 integral with a threaded stud f7 projecting outward somewhat beyond the end of the hub where itreceives a nut 49, a washer 51 being confined between the nut 19 and the outer face of the hub flange 13. A washer 53 integral with the hexagonal member 47, is connected washers 51 and by pins 55 with the grooved disk and is adapted to engage the inner face of the hub flange 13. The construction is such that said flange is confined between the 53 and rotation of the grooved disk with the roll is assured.

Suitable means may be provided to limit outward movement of the roll longitudinally of the rock shaft. To accomplish this, in the present instance, a collar 57 is clamped between a flange 60 on the roll hub and a flange of an internally grooved member 61, said flanges being connected by screw bolts 62. The collar 57 is adapted to engage a fixed collar 63 shrunk on the rock shaft and positively limited against outward movement thereon by a circumferential shoulder 65 integral with the rock shaft. The construction is such that the collar 57 will engage the fixed collar 63 on the rock shiaft and prevent outward movement of the r0 1.

It is important that dust shall not enter between the bushing 23 and the inner surface of the roll bearing thereon. To prevent this, in the present instance of the invention, a sliding collar 73 is fitted on the outer periphery of the grooved member 61 and has a flange 74 adapted to engage a washer 75, engaging in turn an end of a sleeve 77 to be more fully hereinafter described, fast on the rock shaft. A series of coil springs 79 are confined between the flange and the roll limiting thrust collar 57 referred to, and

project through bosses 81 on the sliding collar 73 and apertures in the flange of the grooved member 61. such that dust cannot enter past the gland and grooved ring to the bearingsurfaces of the roll and bushing, and lubricant cannot escape outward from said surfaces be yond the sliding collar 73. The bolts 62 re ferred to, may have reduced ends 6 projecting through ears on the bosses 81 to cause the sliding collar 73 to rotate with the roll hub and wipe against the washer 75.

It is desirable that the rock shafts of the rolls shall have strong fulcrum connections with the rotary head 19 referred to, in order to withstand the duty of revolving the heavy rolls. To this end each of the rock shafts is provided with the sleeve 77 referred to.

of heavy construction, and splitand clamped securely to the rock shaft by bolts 77 (Figs.

9 and 11). Projecting laterally from this sleeve are a pair of trunnions 82 fulcrumed in bushings 83 (Fig. 7) in bearings 85 formed in the rotary head 19 referred to, at opposite sides of a recess 87 in said head to admit the rock shaft. The bearings 85 are provided with caps 89 secured by bolts 91 (Fig. 1) to the head, said caps being connected by a bridge member 93 spanning the shaft receiving recess 87. The trunnion bushings 83 may have closed ends 95 and The construction isthe rock shaft trunnions from the center of the head is such that the axes of the rock shafts are inclined inward toward the axis of thehead when the rolls engage the crushing ring, as will be noted in Fig. 3. As a consequence, when the rolls receive their plans *tary movement, centrifugal force will have a component tending to shift the roll'shafts longitudinally of their axes toward the left of Fig. 3, and thereby tend to prevent outward movement of the rolls along the rock shafts toward the right of Fig. 3 under the influence of centrifugal force. The strong construction of the fulcrum connections for the rock shafts, however, will effectively resist the thrust of the rock shafts toward the left of Fig. 3.

It is found inpractice that increased efficiency als may be had by mounting the rolls to that they have a scuff angle with respect to the crushing ring. In other words, the rolls are skewed slightly with respect to the vertical plane cutting the center of the crushing ring, thereby producing a desirable grinding effect. This scuff angle may be conveniently obtained by mounting the rock shaft in a bore 101 in the clamp sleeve 77, having an axis 101 somewhat oblique to the axis 78 of the sleeve 77 as will. be noted in F i 6.

In other words, the tangent to the periphcry of the active crushing surface of each roll is oblique to the plane of the ring.

Suitable means may be nrovided for lubricating the trunnions S1 of the rock shafts.

To accomplish this, in the present instance of the invention, each rock shaft may have a port 103 (Figs. 9 and 11) communicating with the lubricant supply passage 29 referred to, of the rock shaft, and communieating with an axial duct 105 in a screw plug 107 threaded in the clamp sleeve 77. The duct 105 in turn communicates with a circumferential duet .109 in said screw plug, and the circumferential duct communicates with ducts 11]. extending axially of the trunnions 81 to the outer ends thereof and opening into small chambers 113 (Fig. 7 between the ends of the trunnions and the ends 95 of the bushings for the trunnions. The construction is such that lubricant may pass from the passage 29 through the ducts described to the chambers 113 and from the latter to the surfaces of the trunnions rocking inthe bushings.

of the rolls in reduction of materi- Suitable means may be provided to rotate the head 19. To accomplish this, said head may be provided with an internal hub 115 (Fig. 3) having a tapered bore fitting on the tapered end 117 of a shaft 119 journaled in bushings 121 in bearings 123 carried by bridge frames 125 (Fig. 2) mounted on the base members 1 and secured thereto by suitable bolts 127. At the opposite end of the shaft 119 is a large pulley 129 which may be driven by a belt from any suitable source of power. The pulley 129 may be of substantial size and desirably serve to counterbalance the head 19 and the parts carried thereby. As a consequence, substantially uniform wear is produced on both of the bearings 123 and the shaft will remain in proper alinement.

Suitable means may be provided to limit movement of the shaft 119 in the direction of the axis thereof. To accomphsh this, the inner ends of the bearings 123 may be provided with end thrust bearings, each com prising a split sleeve 131 (Figs. 3, t and 5) having the parts thereof securely clamped to theshaft 11.9 by bolts 133. The split sleeve has a flan e 135 ada ted to en 'a 'e a horseb C) b shoe-shaped washer 1137 adapted to bear against the inner end of the bearing 123. To prevent rotation of this washer, it is provided with holes for insertion on dowel pins 139 projecting from the end of said bearing.

' To protect these end thrust bearings, each may be provided with a box 1&1 semi-circular in form secured by bolts 1 13 to ears 14:5 projecting outward from the bearing. Hinged to the box is a cap 1 17 normally held in closed position by a bolt 1419. The construction is such that the end thrust bearings may. be quickly and easily applied to the shaft and will effectively limit axial movement thereof, and the caps may be readily opened as desired to permit convenient access to the bearings for lubricating the same. The bearings 123 may have openings 151 to receive lubricant for the shaft 119, said openings being normally closed by cov-' ers 153. c

As stated, when the rolls are at rest, the lower rolls will rest on and be supported by the lower are of the ring, whereas, the upper rolls will underthe action of gravity tend to drop away from the upper arc of the ring. Suitable means may beprovided to hold all of the rolls against the ring, so that when their revolution commences and their speed is'too low to develop centrifugal force sufficient to move them to the ring, they will not rock toward and from the ring and injure the rotary mechanism and the ring. As stated, also means may be provided to equal ize the pressures of the rolls against the ring. To accomplish these purposes, in the present instance of the invention, each of the rock shafts is provided with a pair of arms 155 (Figs. 3, 9 and 11) conveniently integral with the clamping sleeve 77 and projecting therefrom inwardly toward the head carrying shaft 119. The outer ends of the arms 155 may be formed to present open bearings in which are seated trunnions 157 of a yoke 159 (Fig. 15). Projecting through a bore 161 in the head 163 of the yoke is a rod 165 having a nut 167 and a washer 169 at one end thereof, a coil spring 171 being confined between said washer and the yoke head 163. The opposite end of the rod projects through an equalizing washer 173 (Fig. and has a rounded head 17 5 seated in a rounded recess 177- in said washer. The washer has a central bearing recess 17 9 seated on a rounde l .end 181 of the head carrying shaft 119.

The construction is such that the coil springs react against their nuts and washers 169 and press the yoke heads toward the right of F 1g. 3, thereby rocking the arms .155 and rock shafts in directions on the trunnions S1 to urge the rolls outward against the crusher ring. By adjustment of the nuts 167, the tension of the coil springs 171 may be varied according to conditions as desired. These springs may be sufiiciently strong and have a tension suflicicnt to hold the upper rolls against the upper arc of the ring at all times, so that when the rolls commence to receive their planetary motion, they will not rock toward and from the ring. As a consequence, injury to the rotary mechanism and ring is prevented, and the life thereof is prolonged. Said springs tend to press all of the rolls toward the ring, but when the rolls are resting on the lower arc of the ring, the burden of supporting such rolls is relieved from the springs therefor, and as a consequence, the springs for all of the rolls become effective to hold the upper rolls against the upper arc of the ring. Therefore, in practice, about one-half the weight of the four rolls is borne by the ring.

it will be understood that the pressure of If one of the rolls is called upon to crush a greater amount of material than another. or if a roll meets harder material. which tends to hold the same farther from the ring than the other rolls, the spring, rod and balancing washer connections between the rolls will tend to equalize the pressure on the opposite roll. If, for example, the lowest roll in Fig. 3 is moved outward from the ring, its rock shaft will swing in a contraclockwise direction, thereby moving the arm and yoke to the left of Fig. 3, increasing the compression of the coil spring for such yoke, and rocking the balancing washer on the fulcrum 181 in a manner such that the uppermost rod is moved toward the right of Fig. 3, thereby increasing the compression of the spring for such yoke, and rocking the arm and rock shaft for the uppermost roll in a contra-clockwise direction and increasing the pressure of the uppermost roll on the ring. Similarly, the effect of the balanced washer and connections between all the rolls will be to equalize the pressures and crushing effect of all of the rolls.

Next will be described the rotary feeder means for delivering the materials to be crushed to the crusher ring at points in front of the individual rolls. This means, in the present instance of the invention, comprises a drum 183 (Figs. 1, 3, 7 and 8) having nozzles 185 projecting in a general radial direction therefrom and terminating in curved delivery mouths 187 havin side openings 189. These mouths preferab y are detachably secured to the nozzles 185 by bolts 191 in order that when they become worn, others may be substituted therefor. In the present instance ofthe-invention, the drum 183 is mounted centrally between the rolls substantially in the plane of the crusher ring, and the nozzles project radially outward into the spaces between the rolls, in order that the delivery mouths thereof may feed the material to the crusher ring in front of the individual rolls.

Suitable means may be provided to support and rotate the feeder means. To accomplish this, in the presentinstance 0f the invention, a circular plate 193 (Fig. 8) may be set in an aperture mone end of the drum, andmay have a flange 195 overlapping the drum and secured thereto by bolts 197. Projecting from said flange are diverging arms 198 conveniently of channel form to furnish strength, securedto the roll carrying head 19 by bolts 199. The construction is such that the feeder means is rotated in unison with the planetary motion of the crushing rolls.

- Suitable means may be provided to feed the material to be reducedto the feeder drum 183. To accomplish this, inthe present instance, a chute 201 is provided having a circular delivery mouth 203entering a circular opening in an end of the drum 183. The upper end of the chute communicates with a hopper 205 mounted on a bracket 207 secured by screws 209 tothe heavy ring 3, referred to. To control the feed of material from the hopper to the chute, a slide gate 211 may be provided adjacent the lower end of the hopper and controlled by a bell-crank handle 213 pivotally connected to the upper end of the hopper.

The construction is such that material to be reduced may be fed from the hopper through the chute to the drum, and will pass thence through the nozales and delivery mouths under the influence of centrifugal lt tends to promote uniform force to points on the crusher ring in front of the rolls. As a consequence, a stream of material will be fed in front of each of the rolls instead of a single stream fed in a mass in front of one of the rolls as has hitherto been the practice. There are important advantages in this distributed feed. crushing effect of the rolls, reduces the amount of material escaping laterally from the crush-er ring without being subject to the crushing effect of the rolls, and thereby reduces the amount of materials to be returned to the mill to be reduced. As a result, the capacity and efliciency of the mill. are materially increased.

As stated, it is necessary from time to time to have ready access to the parts of the mechanism of the mill for purposes of inspection, adjustment and repair of the parts, but when the mill is in operation, the mechanism should be inclosed to prevent the escape of dust and material therefrom. To accom- 'plish these purposes, adoor 215 (Figs. 3 and 6) is provided for the front end of the machine connected to the heavy ring 3 by hinges, in the present instance of the invention, comprising arms 217 adapted to swing on avertlcal shaft 219 (Fig. 1) having its lower end seated in an end bearing in a bracket 221 on one of the base members 1 of the machine, and its upper end projecting through a curved arm 223 projecting laterally from the heavy ring 3. In order that the door may swing easily onthis shaft, it is desirable that the door arms 217 shall not rest on the bracket 221 and the curvedarm 223. To this end a screw bolt 225 is tapped in a boss 227 in the upper door arm 217, and the lower end of said screw bolt is ada ted to rest on the upper end of the hinge shaft 219, said screw bolt being held in its position of adjustment by a lock nut 229. Thus,.the large, heavy door may readily swing on the vertical axis of the hinge shaft 219 witha minimum amount of friction, and aminimum efi'ort onthe part of the operator. To secure the door inits closed position it may be provided with ears 231 and the heavy ring 3 may be provided with ears 233, bolts 235 being adapted to enter registering holes in the door and ring ears tightly to secure the door in :its closed position.

In the present instance of the invention, the chute 201 referred to, passes tlu'oughan aperture in the door 215, as will be noted in Fig. 3, and is secured to said door by bolts 237 projecting through a collar 239 on the chute, and through the door. When the door is swung open, the upper end of the chute will move out lower end of the hopper 205, and the delivery mouth 203 of the chute will move awa from the drum 183. When the door isc osed the upper end of the chute and the delivery mouth thereof will automatiof registration with the cally be brought back into registration with the hopper and drum respectively. To inclose the roll carrying head and parts of the swing shafts for the rolls, a lower casing 2 11 (Figs. 2 and 3) may be provided, mounted on the basemembers 1 referred to, and secured to the heavy ring 3. This lower casing projects upward to the axis of the head carryin shaft 119, as will be noted in Fig. 2. n upper casing is provided above the lower casing in the form of a pair of hollow doors 243 of segmental form, and adapted to be connected to the heavy ring 3 by suitable hinge means, in the present instance, comprising arms 2 15 and 24:7 projecting from the doors 24:3 and adapted to swing on vertical shafts 2&9 having lower ends seated in end bearings in cars 251 projecting from the heavy ring, and upper ends projecting through arms 253 on said heavy ring. To prevent the arms 245 and 247 from resting on the ears 251 and arms 253 respectively, screw bolts 255 may be tapped into bosses in the upper door arms 247 and have ends resting on the upper ends of the shafts 2 19,: said screw bolts being secured in their positions of'adjustment by lock nuts 257. The construction is such that the doors -may swing on the vertical axes of the shafts 249 with a minimum amount of friction and effort on the part of the operator. To secure the doors in their closed positions, swing latches 261 may be pivotally connected to one of the doorsand have screw bolts 263 adapted to engage lugs 265 on the other door. When the doors 243 are swung to their open positions as shown in Fig. 6, they will readily disclose the roll carrying head, the swing shafts, the balancing washer and the connections from the balancing washer to the swing shafts. The head may be turned to progressively present the swing shafts in their uppermost positions, so that ready access may be had to all of the swing shafts and the connections therefor. The door 215 for the opposite end of the mill may be larger than the crushing ring 5, and the liner rings 9, to'allow ready application of said parts to the heavy ring 3 and their removal therefrom as desired. 7

The materials reduced by the rolls will flow over the crusher ring and the liner rings and escape through a discharge opening 267 (Fig. 3) in the lower end of the door 215, and through a discharge opening 269 in the lower end of the casing 241.

The operation of the mill will be readily understood. The shaft 219 driven by the pulley 129 will rotate the head 19 and the feeder. The materials to be reduced will flow from the hopper through the chute to the feeder drum and flow thence through the nozzles and delivery mouths to points on the crusher ring in front of the individual rolls under the influence of centrifugal force. The rolls will press outward under the in,- fluence of centrifugal force against the crushing ring and reduce the materials fed between them, and this pressure may be assisted by the springs 171 in the connections between the rock shafts and the balancing washer. The effect of these connections and the balancing washer will be to tend to equalize the crushing effect of the several rolls.

The mill described is simple and strong in construction, the operating mechanism there of efiiciently reduces the materials, and the parts of the mechanism are readily acces sible when desired.

It will be understood that the invention is not limited to the specific embodiment shown, but that various deviations may be made therefrom without departing from the spirit and scope of the appended claims.

What is claimed is:

1. A crushing mill, comprising, in combination, a fixed ring having a crushing surface. a main shaft, a head carried by said shaft, rock shafts fnlcrumcd on and carried by said head, rolls journaled on said rock shafts and pressed toward said crushing surface by centrifugal force when given a planetary motion, an equalizing member fulcrumed on said main shaft, arms projecting from said rock shafts, spring connections between said arms and equalizing member, a rotary feeder having passages to deliver material to be crushed, and means to feed the material centrally to said rotary feeder that the material may flow outward through said passages under the influence of centrifugal force.

2. A crushing mill, comprising, in combination, a ring. a plurality of rolls cooperating with, said ring to reduce material fed between them, a rotary centrifugal feeder for delivering material in a plurality of streams to said ring, a casing for said parts having a door movable to open and closed positions. a hopper mounted on the casing, and a chute carried by said door and projecting from said hopper through said door to said rotary feeder to dehvcr material from the hopper to the feeder, said chute being movable into and out of registration with said hopper and rotary feeder on closing and opening movements of said door.

3. A crushing mill, comprising, in combination, a ring, a plurality of rolls cooperating with said ring to reduce material fed between them, a, rotary centrifugal feeder for delivering material in a plurality of streams toward the ring, a casing for said parts having a door movable to open and closed positions, and a chute carried by said door for delivering material to said feeder, and movable into and out of communication with said rotary feeder ongslosing and opening movements of said door.

4. A crushing mill, comprising, in combination. a ring, a plurality of rolls cooperat- .ing with said ring to reduce material fed between them, a rotary centrifugal feeder for delivering material toward said ring and having an inlet opening, a casing for said parts having a door, hinge means connectmg said door to said casing, and having a vertical axis, and a chute carried by said door for delivering material to said feeder, said chute being movable to and from said feeder opening on closing and opening movement of said door.

5. A crushing mill, comprising, in combination, a ring having a crushing surface, a shaft, a carrier on said shaft, rolls mounted on said carrier and pressed toward said crushing surface by centrifugal force when given a planetary motion, an equalizing member fulcrumed on an end of said shaft, and connections between said rolls and equalizing member for automatically equalizing the crushing action of said rolls.

6. A crushing mill, comprising, in combination, a ring, a shaft, a head mounted on said shaft,a plurality of rock shafts pivotally connected to said head, rolls on said rock shafts cooperating with said ring to reduce material fed between them, an equalizing member fulcrumed on a part of said shaft, arms projecting from said rock shafts, and spring connections between said arms and equalizing member for equalizing the crushing effect of the rolls.

7. A crushing mill, comprising, in combination, a casing, a ring therein, a main shaft, a head mounted on said shaft within the case and adapted to be rotated by the shaft, rock shafts in said casing pivotally connected to said head and projecting toward the interior of the ring, rolls on the rock shafts and. cooperating with said ring to reduce materials, and spring means within said casing to one side of the path of travel of the roll and adapted to yieldingly hold the rolls in engagement with the ring.

8. A crushing hill, comprising, in combina tion, a ring, a shaft, a head on said. shaft, swing members pivotally connected to said head and having arms projecting inward toward said shaft, rolls journaled on said members and cooperating with said ring to reduce material fed between them, an equalizing washer fnlcrumed on an end of said shaft, yokes fulcrumed on said arms, rods pivotally connected to said equalizing washer and projecting through said yokes, and coil springs cooperating with said rods and yokes to press said rolls outward against said ring.

9. A crushing mill, comprising, in combination, a ring, a main shaft, a head secured to the main shaft and rotated thereby, rock shafts each having a roll jonrnaled thereupon to coo perate with. the ring in crushing materials, each rock shaft having a lubricant supply chamber extendinglongitudinally of the shaft to lubricate the roll jour nail, oppositely disposed trnnnions upon the rock shaft and extending in. a plane offset from the longitudinal axis of the rock shaft, the trunnions being provided with lubricant conducting ducts in commimication with said chamber, and means engaging said trunnions to pivotally secure the rock shafts to said head.

10. A. crushing mill, comprising, in combination, a casing, a ring having a crushing surface within. the casing. a main shaft, a carrier mounted on said shaft within the casing and disposed to one side of said ring, rolls operated by said carrier to crush materials upon the ring, a door hinged to said casing and adapted to form a closure for one entire end of the casing, said door possessing a diameter greater than the ring that the latter may be inserted through the doorway when the door is open, a pair of hollow doors hinged to the casing to swing inwardly toward each. other and each having a vertical and a laterally extending wall forming a housing extending over and inclosing the carrier, said pair of doors when open, adapted to expose the carrier and con neetions between the carrier and rolls.

'11. A. crushing mill, comprising, in combination, a ring, ashaft, a head mounted. on said shaft and rotated by the shaft, a plurality of rock shafts pivotally connected to said head, rolls jonrnaled on. the rock shafts and cooperating with the ring to reduce materials upon the ring, a rotary feeder secured to the head in spaced relation thereto and having passages to deliver materials to be crushed, and an equalizing member fulcrumed between. said head and feeder and connected to said rock shafts to yieldingl hold the rolls in engagement with the ring.

12. ii. crushing mill, comprising, in comhination, a ring, a shaft, a head secured to said shaft for rotation thereby, a plurality of rock slmfts pivotally secured to said head, rolls journah-d on the rock shafts and co operating with the ring to reduce materials, an. inwardly extending arm upon each rock shaft, yolitcs pivotally connected to the inwari lly extending arias, an equalizing incinber fulci'nmed :nljacent said head, and means for yiehlingly connecting the yoltes to the equalizii'ig member to yieldingly hold the rolls in engagement with the ring.

13. A crushii mill, comprising, in comhination, a vertically disposed ring, a plurality of rolls cooperating with said ring to reduce material fed between them. and a rotary centrifugal feeder comprising a drum having nozzles provided. with meeting flaring mouths and outwardly extending throats for directing the materials toward the ring between the rolls, and means to deliver the materials into said drum simultaneously to all of said nozzles.

14. A crushing mill, comprising, in combination, a ring, a mainshaft, a head mount- .e d upon the main shaft and rotatable there by, rolls carried by the head in position to cooperate with the ring to crush materials against the ring, an equalizingmember fulcrumed on said shaft, and connections between the rolls and equalizing member for automatically equalizingthe crushing action of the rolls,

15. A crushing mill, comprising, in combination, a vertically disposed ring, a plurality of rolls cooperating with said ring to reduce materials fed between them, a rotary centrifugal feeder comprising a drum having a central chamber with nozzles extending outwardly from the chamber between the rolls and toward thedrum, and means for delivering materials into said chamber having a delivery mouth lying toone side of the chamber that the materials may be discharged from the mouth in the direction of each nozzle simultaneously.

' 16. A crushing mill, comprising, in combination, a ring having a crushing surface, a shaft having a rotatable head at one end and a driving wheel at the opposite end, spaced bearings between the wheel and head to rotatably' support the shaft, rolls mounted on said head and supported thereby to cooperate with the ring to crush materials, an equalizing member fulcrumed on said shaft, and connections between the equalizing member and rolls to equalize the crushing action of the rolls.

17. A crushing mill, comprising, in combination, a ring, a rotary main shaft, a head mounted on and rotated by said shaft, swing members pivotally connected to the head and projecting toward the interior of the ring, rolls on the swing members and given a planetary movement thereby within the ring for cooperation with the ring to reduce materials between the rolls and ring, and means for imparting a yielding swinging movement to the swing members to force the rolls toward the ring, said rolls being positioned so that the tangent to the periphery of the active crushing surface of each roll and within the plane of rotation of the roll is oblique to the plane of the ring.

18. A crushing mill, comprising, in combination, a fixed ring, a shaft, a carrier mounted on said shaft, members mounted on the carrier and movable relatively thereto, crushing rolls mounted on said members and movable toward or from the interior crushing surface of the ring, means for yiel din g1 y urging the rolls outward toward the ring, said shaft, carrier and roll supporting members being rotatable to cause the rolls to have a planetary grinding action on materials between said ring and rolls, each of said rolls being mounted so that the tangent to the periphery of the active crushing surface of each roll and parallel to the plane thereof is oblique to the plane of the ring.

In testimony whereof I have signed my name to this specification.

THOMAS J. STURTEVANT.

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