US755725A - Ore-crushing mill. - Google Patents

Description

' I0 MODEL.

A PATENTED MAR. 29, 1904. B. A. WALL.

ORB GRUSHING MILL.-

APPLICATION FILED 53. 6. 1903.

V IH: nomnspcnins OILPNOTO-LIYHDN vusumommy c UNITED STATES Patented March .29, 1904-.

PATENT OFFICE.

ENOS A. WALL, or SALT LAKE CITY, UTAH,

ORE-CRUSHING MILL.

SPECIFICATION forming part of Letters Patent No. 755,725, dated March .29, 1904.

Application filed February 6, 1903. Serial llo. 142,148. (No model.)

To all whom it may concern.-

Be it known that I, Enos A. WALL, a citizen of the United States, and a resident of Salt Lake City, in the State of Utah, have invented certain new and useful Improvements in Ore- Crushing Mills, of which the following is a specification.

My invention relates to that class of orecrushing mills designed to receive ores or rock which. has been previously broken into fragments of two inches and smaller in diameter and to reduce the same to the smallest possible size consistent with the production of a perfectly granular pulp, and having this ob ject in view I assume the following conditions to be self evident and indispensable-viz., that the crushing-surfaces mustfnot grind or slip upon themselves nor upon the material sought to be crushed and that such crushing can only be eflected by direct pressure-such, for instance, as would result from the passing of the wheels of a car moving in a straight line upon a smooth track over pebbles placed upon the rails. The pulp resulting from such contact, though infinitely fine, would still maintain granular or angular form. A crushing-mill operating upon this principle will possess the highest degree of durability and require the minimum of propelling power; but it is not economically practicable to reduce particles of the size mentionedc'. 6., two-inch cubes to fine powder at one operation, nor with same form or type of crushingface, for reasons that are familiar to those skilled in the art. On the contrary, machines should be adapted to crush two-inch cubes to about one inch, one-inch cubes to half-inch, and half-inch to one-fourth inch, which size and smaller may be reduced at one operation sufiiciently small to pass through a thirty or forty mesh wire screen or to the smallest size desired for effective concentration, amalgamation, or lixiviation processes. Of all gradations that of finishing or line crushing is most difiicult and the resulting character of the pulp most important. If the granular or crystalline structure of the particles be destroyed, as by abrasion between the sliding or grinding faces of the crushing-mill,

they become at once impervious to the percolation of leaching solutions and absolutely refractory to all known processes of concen-- nular grooves, thus rapidly destroying their efficiency. These rolls are. secured in place a short distance apart, according to the degree of fineness to which it is desired to reduce the material and are held in position with strong spring-buffers or other yielding devices, which places the entire crushing strain upon the journal-bearings of the rolls, thus involving the application of much unnecessary driving. power, while the continued makes it necessary to provide ponderous bedframes and expensive foundations.

My invention is designed as an improvement upon my crushing-rolls patented December 22, 1885, No. 332,978, and upon the various types of so-called Cornish rolls in common use; and it consists in part in placing one roll directly above the other and in contact therewith, the purpose being to effect the crushing of the ores or other material by means of the Weight of the upper or crushing roll alone and without the intervention of springs or other pressure devices. The upper roll is journaled in bearings held loosely in guides formed of the opposite sides of the main frame, so as to admit of unobstructed up-and-down movement, and the lower roll is journaled stationary in bearings secured to the main frame. My

upper or crushing roll having this free upand-down movement, unobstructed by pressure-springs or other similar devices, will travel upon the lower roll, producing a crushshock resulting from vibration of the springs ing effect precisely similar to that which would result from rolling in a straight line over a flat smooth surface. It is of the utmost importance, however, in order to obviate any grinding effect that both rolls be made to revolve at the same speed, and to insure this result, in addition to having both rolls belted to revolve at the same speed, I provide light steel gears, the only ofiice of which is to hold the upper roll back from any tendency to slip upon the lower roll, due to momentum added by the heavy balance-wheels hereinafter referred to and to the inequalities of belt-driving.

To give additional weight and momentum to the crushing-roll, it is provided with two heavy balance-wheels. The combined weight of the balance-wheels and the crushing-roll to which they are attached must be sufficient to crush the largest pieces of ore fed to them to the degree of fineness desired. It is evident now that if the feed be introduced in such volume that the sheet of ore spread upon the lower roll be of greater thickness than the larger particles 2'. 0., if one grain of ore piled upon the top of othersthe resulting product will be less finely crushed than if spread out in a sheet of the thickness only of the larger particles, from which it will be seen that the degree of fineness of the pulp may be readily controlled by regulating the volume of feed, which being automatic is in the highest degree simple.

In order that the point of contact or crushing-point between the roll-faces shall at all times be provided with the desired volume of feed, the ore is fed upon the lower roll through a chute of the width of the face of the rolls. This chute must be placed at an incline, upon which the ore particles will readily fall by gravity, the supply being constant and controlled in volume by automatic devices, such as are in common use and not necessary to here illustrate. The ores will then in the fall be spread out in a sheet of the width of the rolls and practically of uniform thickness. This sheetof ore is discharged upon the lower roll as far as practicable away from the point of contact with the upper roll. The material will then be carried to the crushing-point with the peripheral velocity of the rolls and will be crushed by direct pressure of the upper roll, the production of all refractory slimes being thereby avoided. In order that the material shall be retained when fed upon the lower roll, shields or guardplates are attached to the lower roll, projecting a few inches beyond the outer rim of the lower roll and overlapping the ends of the upper roll, as provided in my crushing-rolls patent before referred to, thus forming a continuous trough into which the ore is fed and by means of which the feed is' uniformly spread to the extreme outer rim of the roll-faces, and thus a perfectly even wear is insured. In practice I find that the projecting portions of the shields or guard-plates in time wear by contact with small ore particles falling between them and the ends of the upper roll. To overcome this difiiculty, I provide the inner faces of the shields with removable plates of hardened metal made in segments and secured to the shields by means of short bolts.

I accomplish the above objects by the mechanism shown in the accompanying drawings, in which- Figure 1 is an end elevation of my crusher. Fig. 2- is a side elevation, partly in section; and Fig. 3 is a detail view of a portion of the lower roll with its shield and Wear-plate.

A designates the framework formed, preferably, of timbers or beams bolted firmly together and having vertical guideways A at its opposite sides. These guideways A are formed by the uprights A the adjacent sides of which are provided with metallic linings or wear-plates A B is the lower roll with it shaft 6 mounted in fixed bearings 6 within the lower end of the guideway A, and the ends of the shaft extend beyond the sides of the frame, one end of the shaft being provided with a drive pulley or Wheel 6 and the other end having a light steel gear-wheel 72 The ends of the roll B are provided with shields B in the form of rings which are of greater diameter than the roll and bolted thereto. In order to compensate for the wear which takes place at the juncture of the shields and ends of the roll, I provide the inner sides of the shields with removable segments B which may be readily removed by first loosening the shields from the roll and then removing the bolts 6*. In order that the segments B may lie flush with the inner faces of the shields B, the latter are provided in their inner faces with annular recesses or grooves which extend to the peripheries of the shields, and these grooves extend inwardly within the radius of the crushing-roll B, as shown in Fig. 3, so as to fill the angles between the ends of the rolls and inner faces of the shields .without spacing the shields away from the ends of the roll.

C is the crushing-roll, having its shaft C mounted in the vertically-sliding bearings C within the guideway A and having a drivingpulley C.

The rolls B C are belted to rotate in opposite directions.

The crushing-roll bears at its lowest portion on the highest portion of the lower roll, and so exerts its full weight on the material, which would not be the case with a crushingroll arranged out of vertical alinement with the lower roll, for then some of the force of the upper roll would necessarily be taken up by the inclined guideways and much friction would result also in moving the crushingroller upward and outward. In my mill the whole weight of the crushing-roll is exerted, and as the roll is absolutely unrestricted in its up-and-down movements by springs of any 'sort the sudden shocks and strains to the framework incident to the use of springs is entirely avoided, and so the framework may be entirely of wood, save that the wear-plates A should be of thin plate metal. The cost of heavy cast framework is therefore done away with.

The weight and momentum of the crushingroll is increased by two heavy fly-wheels F F, one at either side, and one end of the shaft has a thin steel gear C which meshes with the lower gear 6 These gears b C are of the same diameter and serve merely to hold the crushing-roll against slipping upon the lower roll and against moving any faster than the lower roll,and so cause the formation of a perfectly granular pulp, and thereby avoid the production of refractory slimes.

D is the chute of the same width as the face of the roll B and serving to feed the material in a thin even sheet to the rolls, the point of delivery being, as shown in Fig. 2, as far from the crushing-point as practicable.

The chute may be supplied from any of the well-known automatic feed mechanisms, not necessary to show here, as they are well known and not claimed herein.

The shields will serve to prevent the material from falling beyond the sides of the rolls, as they form a sort of guide-tr'ough.

In crushing ores from sizes of two-inch cubes to half-inch the crushing-surfaces should be corrugated, as provided in my Patent No. 332,978, above referred to, because this form of crushing-face admits of a much smaller mean diameter in order to secure the necessary grip or bite upon the material to be crushed; but where a fine product is desired, as in reducing material one-fourth inch in size to thirty mesh or smaller, I prefer that the rolls be constructed with plain crushingfaces and of diameter of at least thirty-six inches.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination with a frame and a lower roll mounted in fixed bearings therein, of an upper driven crushing-roll having free vertical movement toward and from the upper side of the lower roll, to crush the material passing between the rolls, and an independent driving means for rotating the upper roll in an opposite direction to the .lower roll and at the same rate of speed.

2. The combination with a frame and a lower roll mounted in fixed bearings therein, and provided with a pulley for belt-driving, of an upper oppositely-driven crushing-roll having free vertical movement toward and from the upper side of the lower roll and provided with an independently-driven pulley of the same size as the pulley of the lower roll.

3. The combination with aframe and alower belt-driven roll mounted in fixed bearings therein, of the upper crushing-roll free to move vertically, belt-driven in the opposite direction and at the same rate of speed as the lower roll, and means for preventing slipping and faster movement of the upper roll due to independent belt drives.

4:. The combination with a frame, a lower belt-driven roll mounted in fixed bearings therein, shields at the ends of the roll and removable plates flush with the inner sides of the shields and overlapping the ends of the roll, of an upper crushing-roll having free vertical movement and belt-driven oppositely to and at the same rate of speed as the lower roll.

5. In combination with the crushing-rolls, one roll being placed above the other and journaled in bearings secured in guides in the main frame, so as to admit of free yielding upand-doWn movement, the shields or guardplates at the ends of the lower roll, and overlapping the ends of the upper roll sufiicient to form a trough for the retention of the material to be crushed and to permit its being carried forward upon the surface of the lower roll across the point of crushing contact, and heavy balance-wheels attached to the main shaft of the upper roll at opposite ends of the said roll and within the frame, substantially as and for the purpose herein specified.

6. In combination with the one roll being placed above the other and journaled in bearings secured in guides in the main frame so as to admit of free yielding up-and-down movement said rolls being belt-driven, the shields or guard-plates at the ends of the lower roll and overlapping the ends of the upper roll sufficient to form a trough for the retention of the material to be crushed and to permit its being carried forward upon the surface of the lower roll across the point of crushing contact, the heavy balance wheels attached to the main shaft of the upper roll, and gear-wheels placed upon the ends of main shafts of the crushing-rolls and engaged in such manner as to control the-speed of the upper roll and prevent its slipping upon the face of the lower roll, substantially as and for the purposes herein specified.

7. In a crushing-mill, a roll having end shields of greater diameter than the rolls, and provided on their inner faces with annular recesses extending inwardly within the radius of the roll and segmental wear-plates removably secured in said recesses, flush with the inner faces of the shields.

8. An ore-crusher comprising, a main frame having vertical guideways, a lower beltdriven roll having its bearings fixed, annular shields at the ends of said roll, an upper eppositely belt-driven crushing-roll in the verlower roll and delivering thereon, substari tical plane of the lower roll and having an untially as and for the purposes herein specified. I obstructed movement to and from the face of In testimony whereof I aiiix my signature in the lower roll, meshing gears of the same size presence of two Witnesses.

5 on the shafts of the said rolls to prevent slip- EN OS A. WALL.

ping and faster movement of the upper roll Witnesses: due to inequalities of belt-driving, and a feed- WILLARD HANSON,

chute of the same width as the face of the W. R. SMITH.

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