US2291992A - Crushing machinery - Google Patents

Description

cnixsume mcmmany Filed Sept. 9, 19: s9

7 ShGGtS ShGGt 1 5/15/1100 Ema/"n5 INVENTOR ATTORNEY Aug. 4, 1942. s. STEARNS causnms MACHINERY Filed Sept. 9.1939

7 Sheets-Sheet '2 I VENTOR ATTORNEY Aug. 4, 1942.

S. STEARNS CRUSHING MACHINERY Filed Sept.- 9, 1939 7 She ets-Sheet- 5' ATTORNEY Aug. 4, 1942. s. STEARNS CRUSHING MACHINERY 7 Sheets-Sheet 4 Filed Sept. 9, 1939 7 4 NJ IEZQIWWM E ATTORNEY Aug. 4, 1942. 1 s. STEARNS 2,291,992

CRUSHING MACHINERY Filed Sept. 9, 1939 7 Sheets-Sheet 6 .5/75/00/7 jfaams ENTOR /fllw w ATTORNEY Aug. 4, 1942.

s. STEARN'S 2,291,992

CRUSHING MACHINERY Filed Sept. 9, 1959 7 Sheets-Sheet 7 F 7 J4 Y Z film/don .fi/Efirns m NTOR ATTORNEY Patented Aug. 4, 1942 UNITED STATES PATENT OFFICE cnvsnme MACHINERY Sheldon Stearns, Westfield, N. J. Application September a, 1929, Serial No. 294,089 creams. (Cl. 83-10) My invention relates to improvements in crushlng machinery, in particular to the type of crushing machinery known as gyratory crushers in which material is crushed in two or more stages as full described in my patent, No. 2,147,721, issued February 21, 1939, and the present application contains common subject matter with my abandoned application, Serial Number 108.178, filed October 29, 1936.

In such a multi-stage gyratory crusher there are two or more centrally located conical crushing heads mounted upon a vertical shaft. One end of this vertical shaft is gyratedby means of an eccentric driven directly or indirectly by a motor. The other end of the shaft is centrally and pivotally mounted. Surrounding these conically shaped heads are stationary concaves or crushing surfaces so shaped as to form a large entrance opening between each conical head and its concave at the top, and a continuously narrowing space between each head and its concave towards the lower or discharge end. The shaft with its heads does not revolve, but is so gyrated that the heads move towards and away from their concaves at every point of the circumference, once for every revolution of the eccentric. The minimum clearance between .each of the heads and their corresponding concaves for any stage is at their discharge ends. vMaterlal to be crushed is introduced at the top or entrance opening between the head and its concave of the fl'rst crushing stage, and is gradually crushed to size as it passes through the succeeding crushing stages due to the gyrating motion of the heads, until it isfinally discharged from the last stage of the crusher. In other words, the first crushing stage serves to crush the material from its original size to some definite intermediate size, and is discharged from the first crushing stage and allowed to enter the second crushing stage. Two or more stages are used for crushing the material from its original size to the desired final size. The clearance between the concave and the crushing head of the first stage at their discharge ends is so designed and independently adjustable at its discharge point that it does not pass more material at that point than can be accommodated or crushed during an equal interval oftime in the second crushing stage. If the crushing of the material is accomplished in more than two stages, the clearance between the concave and the crushing head at their discharge ends of each crushing ,stage is so proportioned and adjustable that it does not pass more material than can be crushed in an equal interval of time in the succeeding stage. Material in passing from stage to stage is gradually crushed to a finer size until it reaches the desired degree of fineness when discharged from the last stage. In order to accomplish this the volumetric capacity of the stage and the discharge area must be kept equal. As wear takes place on the crushing surfaces of the heads and concaves the volumetric capacity increases and also the discharge area, which permits a coarser product and larger volume to discharge into the succeeding stage. Therefore it is necessary to keep the volumet c and discharge areas from increasing by adjusting the concave ring upwardly. When it is desired to increase the volumetric capacity and discharge area of any given stage the adjustable concave ring is moved downward. When adjustment in a two-stage crusher is desired in the bottom stage and is accomplished by vertical adjustment of the gyrating shaft, the top stage concave is then adjusted to give it the same capacity as the bottom or second stage. The amount of wear of the crushing surfaces of the heads and concaves in the various stages is not the same over an equal period of time. Therefore it is necessary to adjust each stage individually in order to keep the discharge capacity and volumetric capacity of all stages equal.

The amount of wear of heads and concaves in any given stage depends upon the ratio of reduction and size of the product being crushed. The smaller the product the less will be the percentage of voids or spaces it contains and therefore the wear and friction will be proportionately greater.

In order that a multi-stage crusher may function properly and avoid packing in any stage at any setting all of the stages must have equal volumetric capacity and equal or substantially equal discharge areas with relation to those of the preceding stage. To accomplish this each stage of the multi-stage crusher is constructed so that each individual stage can be adjusted separately to take care of the increase or decrease in volumetric capacity and discharge area.

My invention includes so designing and constructing the concaves of a multi-stage crusher that each of them can be adjusted or moved vertically with respect to the heads entirely independent of one another and without making any vertical adjustment of the heads.

An important advantage in having each concave adjustable independently of any of the others lies in the fact that it may be desirable to change the minimum clearance of any one stage, that is, the discharge opening of any certain stage.

so as to change the amount of material discharged from that stage, when it is found that such a stage discharges more or less material than can be discharged from an oil the other stages in equal intervals of time.

This advantage is of especial value in multistage crushers since as wear of heads and/or concaves'takes place in any stage it is necessary to adjust all stages to have equal capacities or discharge areas as volumetric capacity increases rapidly when the crushing surfaces of the heads and concaves wear to any extent. In a two stage crusher it has been found that. the crushing heads and concaves of the second or fine stage will wear approximately twice as fast as those of the first or coarse stage. Therefore, to maintain the crusher at maximum emciency of opera= tion it is necessary to adjust the concaves of one.

stage or the other to substantially equalize the discharge areas and volumetric capacities of the stages. Also, the adjustment of the concaves changes the ratio of reduction and permits regulation of the percentages of various sizes or product which may be produced.

I'he concaves and crushing heads of a stage of a multi-stage crusher may wear sumciently to increase the volumetric capacity of the stage to such an extent that the succeeding stage of the crusher could not handle the increased capacity, which would result in choking or" the crusher with possible breakage of parts. Adjustment of the concaves or the stage having the excessive wear may under the present invention be made to compensate for such wear and reestablish the proper proportions of the various stages.

Another important advantage of having each concave adjustable independently of the position or the other concaves l es in the fact that an operator may wish to re-set the crusher so as to produce a product somewhat finer or coarser than that which the crusher is producing. As an example, let us say that we have a material that each adjustable concave is supported in a fixed position by a continuous support extending around the entire circumference of the concave and this continuous support is capable of taking either an upward or a downward thrust. Such thrusts may be of considerable magnitude during a crushing operation.

Another advantage of my invention lies in the fact that full adjustment can be made on each concave irom the exterior of the machine without having to open the machine in any manner.

Another important advantage of my invention is that each concave can be adjusted by means entirely separate from the means for looking or holding the concave in place after the proper adjustment has been made.

Another important advantage of my invention lies in the fact that by extending the upper part of the concave into a corresponding recess in the frame of the crusher the means for adjusting and locking the concave can be made dust proof and also act as a shield to prevent small crushed material from filling or packing in the clearance space between adjusting means and frame of the crusher It should be noted that in a multi-stage gyratorycrusher having individually adiustable concaves the usual adjustments that can he se is being crushed in a three stage crusher from an initial 4" sizeto a final /4" size, and let us say that the minimum discharge clearance between head and concave of the first stage is 2%,", that of the second stage and that of the last stage A", Suppose now that it is desired to produce a material, say a finished prod= not of in size. In orderto secure maximum output of the crusher, at the finer setting, it may be advisable to set the minimum discharge clearance between head and concave of the first stage to 2" instead of 2 and that of the second stage to rather than /4", and set the final minimum discharge clearance, that is, the discharge clearance between the head and concave of the third stage, at is" instead of With independently adjustable concaves in each of the three stages this can be readily accomplished although the necessary amount of vertical adjustment is diflerent for each stage. Changing the ratio of reduction in the stages will change the screen analysis of the finished product, giving a cured by the vertical movement of the gyratory shaft and heads are not impaired in the least. Combined adjustments or both the heads and the concaves can be made should it be desired to secure readjustments of the crusher beyond the adjustments that can be secured by moving the concaves alone.

Ai. further object oi my invention is to provide a comparatively simple and inexpensive multistage gyratory crusher constructed and arranged whereby regulation of the discharge or the second or final crushing stage is provided by adjustment of the gyrating shaft and the crushing heads, while adjustment of the discharge opening of the first stage is provided by adjustable concaves, ad- ,iustable independently of the shaft and cones, thereby permitting relative adjustment of the crushing stages for regulating the nature of the product produced by the crusher, and reducing the percentage of fines or small sized particles in the final product, as will be more specificaiiy set out hereinafter.

For a more detailed understanding of my invention reference is to be made to the following description and the accompanying drawings of practical embodiments of the inventive idea, and in which drawings:

Figure l is a part sectional view of a three stage gyratory crusher showing particularly the gyrating heads and their corresponding adjustable concaves.

Figure 2 is a halt-sectional view of a part of the crusher of Figure 1 showing to an enlarged scale the crushing heads with their correspond= ing concaves and showing more clearly the method of adjusting the latter.

Figure 3 is a half cross-sectional view of a modified form of Figure 2.

Figure i is a cross-sectional view of the crusher along the line d-E of Figures 2, 3 and 5.

Figures 8 and 9 show a sectional and end view of the third stage concave showing its adjusting bolts.

Figure 10 is a sectional view of the third stage concave and wedge and also the crusher frame showing the set screws used for limiting the upward movement of the concave.

Figure 11 is a sectional view of the crushing heads of a crusher with their corresponding concaves but showing another method of adjusting the latter.

Figure 12 is a plan view of a shim as used in Figure 11.

Figure 13 is a fragmentary section through the improved crusher illustrating in dotted lines a condition of wear on the concaves and heads.

Figure 13 is a view similar to Figure 13 only showing the concave adjusted to maintain the desired size of the discharge opening of the stage.

Figure 14 is a vertical section through a modified form of the crusher.

Referring to Figure l, the electric motor for driving the crusher is shown at I. This motor drives the vertical shaft 2 through the coupling 3. The lower end of the vertical shaft 2 is keyed and fastened to an eccentric bushing 4. The outer surface of the eccentric bushing is journalled in a stationary frame 5, and the inner surface of the eccentric bushing rotates about the hollow gyrating shaft 6. This hollow gyrating shaft permits the driving shaft 2 to pass through it without contact, and carries the crushing heads I, 8 and 9 on its enlargedtapered portion. The gyrating shaft 6 near its upper end is centered and pivotally mounted in a ball seated bearing l0, and is supported at its threaded upper portion by the nut H. The motor I in turning the shaft 2 rotates the eccentric 4, which in turn oscillates the gyrating shaft 6 about its upper and centrally located pivot Ill. The weight of the motor and that of all the rotating and gyrating parts is carried by the spider casting I! mounted upon the stationary frame or casing l3. Shaft 6 together with the conical heads I, 8 and 9 can be raised or lowered by means of the adjusting nut ll. Frame I3 is suspended by a number of suspension wire ropes Hi from a fixed support above the crusher and not shown in the figure. Surrounding the crushing heads I, 8 and 9 are concaves if, it and 17. These concaves are in the form of a continuous ring casting and are separately mounted in the stationary supporting frame 3.

The supporting frame or casing is shown in Figure 1 as made in one piece although the frame can be made in sections bolted together as shown in Figure 11. As the diameters of the head and concave of the first stage are much less than those of the second stage, and the second stage much less than the third stage and so on, the frame of the casing is stepped out in diameter from stage to stage as shown in Figure l, so as to accommodate the larger heads and concaves of succeeding stages.

As shown in Figure l, the clearance spaces between the crushing heads and their corresponding concaves of any stage are larger at their top than at their bottom or discharge end. Material isintroduced into the space at the top between the crushing head I and concave l and is crushed to the size of the minimum clearance between this head and its concave at their discharge ends. In multi-stage crushers of my invention the diameter of the discharge of any stage is considerably smaller than the entrance opening. This conveying or guiding surface need not have much slope because the surface not only gyrates and tilts inall directions but is subject to the usual vibrations accompanying the operation of a gyratory crusher, hence material as it leaves the discharge opening between the crushing head I and concave I5 is guided by the sloping surface l8 of the crushing head 8 into the receiving opening of the next crushing stage, that is, into the upper part of the clearance space between the head 8 and the concave l6. In the clearance space between the crushing head I and concave I6 the second stage of crushing is performed. The minimum clearance at the bottom of this space is less than the minimum clearance in the first crushing stage. The material after being discharged from the second crushing stage is guided and conveyed by the sloping surface 20 of the gyrating head 9 to the entrance of the third crushing stage, that is, the top clearance space between the-crushing head 9 and concave H. The minimum discharge clearance between the third crushing head 9 and its concave I1 is made so as to deliver the crushed material at the desired size or fineness. The material upon being discharged from the-last crushing stage drops upon the inclined surface 22 of the frame and is discharged through a suitable opening 23 of the frame of the crusher.

Figures 2 and 3 show the heads and concaves of Figure 1 to an enlarged scale. Similar numbers in the figures refer to similar parts. Concaves l5, l6 and I! are vertically adjustable by means of bolts 25, 26 and 2'1 and set screws 34, 36 and 35 (see Fig. 6), and are held in place by the tapered wedges 3i, 3? and 33. These tapered wedges have straight cylindrical surfaces where they are in contact with the straight cylindrical surfaces of the concaves, and they have tapered or conical surfaces on their opposite sides where they fit against conical surfaces on the stationary frame l3 surrounding the concaves. Bolts 28, 29 and 30 serve for raising and lowering these tapered wedges. When the wedge is drawn vertically upward it looks the concave in place and when lowered it loosens the concave. These tapered wedges are arcuate in form extending through almost of are, so that four of these wedges reach practically around the circumference allowing a small opening or space between each arcuate wedge. The tapered wedges when drawn upward by their bolts support the con--v caves around their entire circumference and r gidly hold the concaves in a definite fixed position. The minimum clearance between any concave and its corresponding head can be increased by moving the concave vertically upward and the minimum clearance can be decreased by vertically lowering the concave. In adjusting the concave I5 to a new position the nuts on bolts 25 are first slacked and then the nuts on bolts 28 are loosened and by tapping the top of bolts 28 with a hammer the four arcuate wedge pieces are driven downward relieving the locking pres sure between the wedges 3i and the ring concave 15. The concave then can be either raised or lowered vertically by means of the nuts onbolts 25 and by adjusting set screws 36 and after the concave I is placed in the desired position by proper adjustments of set screws 3% and bolts 26 the arcuate wedges 31 can then be drawn up 'by means of the nuts on bolts 2% which finally face on the frame it of the crusher.

manner as above described for adjusting concave E5 of the first stage. Concave it has adjusting bolt 26, set screw 35 and arcuate wedges 32, the latter held in position by bolts 29. Concave ll! has adjusting bolt 2?, set screw 36 and arcuate wedges 33, the latter held in position by bolts 3%.

In making all these adjustments or the concaves as above described it is not necessary to reach within the crusher but all adjustments can be made externally of the crusher as the means for adjusting and the separate means for locking or fixing each concave all extend through the frame of the crusher and are easily accessible. It should be noted that the concaves W3, it and ill are shown in Figure 2 as having their upper portions extending into circular recesses 83' of the frame it. These recesses form overhanging annular lips it and are deep enough so that the tops of the concaves are never entirely withdrawn from their recesses when the concaves are adjusted vertically downward. The object of these recesses is to prevent small particles of the crushed material from passing between the top of the concave and the horizontal portions of the frame immediately above the concaves, thereby filling the space between the top of the wedges and the frame. If finely crushed material hecomes lodged in the space above the concave and its corresponding wedge it may interfere with a subsequent upward adjustment oi the concave. This recess construction need only be used when material is being crushed which pulverizes and cakes easily, Normally this recess construction can be omitted as shown infigure 3. The concaves 85, it and i'l' shown in Figure 3 are similar to concaves 953, it and El respectively, shown in Figure 2, except that they do not extend into the annular recesses of frame it as shown in Figure 2. The annular recesses are omitted in Figure 3.

Figure l shows a cross-section through one of the six arms of the second stage crushing head carrying the mantle 8, along the line iii of Figures 2, 3 and 5. These arms extend from the hub of the head to the outer ring of the head upon which is supported the mantle ii. In Figures 2 and 3 the intermediate conical head and the lower conical head are shown with six arms each connecting the hub of the head with its outer rim.

Figure 5 shows a sectional view along the line 5-5 of Figure 2. The arcuate wedges 32 for holding concave IS in place are shown in Figure 5 in four parts with a slight space between the ends of each part. It also shows three bolts 29 for drawing up each of the arcuate wedge pieces 32 and eight bolts 26 and four set screws 35 for holding the ring concave I6 in place. The arcuate wedge pieces 33 are shown in four parts around the circumference, each part held by three bolts accuses 3t and for holding the ring concave ll eight bolts 2i! and four set screws 3% are provided. The conveying surface it in Figures 2 and 3- is made of wear resisting material and is built up in three sections for ease of assembly. The same construction is used for the conveying surface 20.

Figure '7 shows a cross-section through the arcuate wedge 33 having a vertical surface against which the ring concave is supported and a sloping surface on the opposite side of the wedge which fits against a corresponding tapered sur- This surface is shown notched so that it can be packed with grease, making the dismantling of this piece easier. The. bolt 30 is shown having a head which can receive the blows of a hammer for loosening the wedge should the tapered portion of the wedge have been seized too firmly by the frame oi the crusher. The same construction as here shown is used for wedges 3| and 32 and their corresponding bolts 28 and 29.

Figures 8 and 9 show the method of attaching the bolts 2'! to the concave IT. The concaves are made of manganese steel castings or other wear resisting material and are difiicult to machine. Therefore slots are cast in the concave which can receive the T head of the concave bolts. Concave ill and T bolt 2i are shown in this figure and the same construction is employed for concaves l5 and 8G and their corresponding T bolts 25 and 25.

Figure 10 is an enlarged cross-section of the concave il,wedge 33 and set screw 35, of which there are four to each ring concave. These set screws hold the concave from moving vertically upward after it is once set in position and especially during the time when the wedges 33 are drawn into place for locking the concave ll. Set screws 36 also serve in assisting the wedges 5:33 in looking the concave i'i against any vertical movement due to the upward thrust on the concave when it is crushing. Similar set screws are used for holding concave it and set screws 35% for holding concave it in place.

Figure 11 shows a difierent method of vertically adjusting the concaves of a multi-stagecrusher.

in this design the frame it of the crusher is made in three sections bolted together as shown in the figure instead of a single piece as shown in Figure l. The concaves are held in position by shims both above and below the concaves. Concave i5 is held in position by the nest of shims El and 3B and concave ill by the nest of shims t9 and 4t, concave ll by the nest of shims ll and d2. To adjust concave l5 vertically upward some of the shims in the nest of shims 31 are taken out and inserted with the nest of shims 38, thereby raising the concave and for adjusting the concave downward the reverse takes place.

are taken out and placed with the nest of' shims 3i. Concaves i6 and H are adjusted in a similar manner. The shims in each nest contain some very thin shims, others that are moderate in thickness, and others that are thick, so as to readily make the adjustment to any definite dis- That is, some of the shims in the nest of shims 38 p I3 before adjustments can be made. However, by the use of means for adjusting the concaves as shown in the previous figures the concaves can be adjusted without disturbing the frame of the machine or any other important part because the adjustable means extend to the exterior of the frame from where the proper adjustments can be made. Some crusher the simplicity of the shim of the fact that the sections of the frame would have to be unbolted in order to adjust the conoperators may prefer caves.

I have found that in definitely locating the concaves of each head by the use of shims it is necessary to have each concave supported or held at both its upper and lower ends by shims. During the crushing operation there is usually a thrust on each concave in an upward direction tending to lift the concave.

Figure 13 illustrates in dotted lines at A and B wear on the adjustable concaves and clearly shows that such wear will cause an increase in the discharge outlet C of the respective stage of the gyratory crusher. The wear in gyratory crushers, particularly on the concaves, is much greater at the lower part of the concave. Such wear on the concaves I5 and the conical crushing heads I, as indicated by the dotted lines, will increase the capacity of the respective stages as well as increasing the size of the discharge outlet, and since the wear will not be equal in all of the stages of the crusher, will cause an unbalancing of the capacities of the respective stages, resulting in choking of the crusher and also resulting in variation in the size of the product.

In case of such wear, the concave I5 is adjusted by means of its adjusting screw 25, being lowered as shown in Figure 13 until the discharge out-' let C of the stage is of the proper size and crosssectional area to, first, produce the proper size of the product desired, and, second, to re-establish the balance or proper proportions between the discharging areas of the various stages of the crusher. After the concave has been adjusted to its proper position it is locked therein by means of the adjusting locking screw structure 28.

Figure 14 of the drawings shows a longitudinal section through a modified form of the multistage gyratory crusher. This modified form of crusher is a belt or gear driven crusher, the gyrating sh'ait I being driven from the power take-oil shaft IOI through the gear mechanism I02, in contradistinction to the direct type of driven crusher shown in Figure l of the drawings. The gyrating shaft I00 has the cone I03 mounted thereon, which has the removable arrangement in spite crushing heads I04 and 105 mounted on its outer cones I04 and I00, through the medium of the adjustment providing structure shown at III. This adjustment providing structure III comprises the threaded end III' of the shaft I00 and the nut III'nwhich cooperates with the bearing structure III".

," The adjustment of the concave I00 of the first stage of the multi-stage gyratory crusher permits relative adjustment of the crushing stages of the .crusher for varying the ratio of one stage to the other for regulating the nature of the product produced by the crusher. By variation of the ratios of the discharge of the first stage and the discharge opening of the second or final stage, different types of product may be obtained.

For example, when crushing a hard rock, operating with the concaves set so that the first stage receives a feed of plus 1%" minus 2%" and discharge opening on closed side set at 1%" and with the final discharge of the second stage set at 1 the crusher produced a final product of which 34 per cent was fines. That is, 34 per cent of the final product was minus 54;" in size. By adjusting the concave to reduce the discharge opening of the first stage to 1% closed side, without. any variation of the final discharge of the second stage from its 1 setting, the percentage of fines was very materially reduced and under such operating conditions only 19 per cent of the final product was minus in size.

The conditions just set out vary with different types of material and size of feed to the crusher and by providing comparatively easy and inexpensive adjustment of the first stage, the crusher may be adjusted to produce a" fine or coarse product without changing the discharge is adjusted by means of the bolts H4 and the nuts H5 thereon into the desired position and is locked therein by means of the locking wedges H3 and the locking screws H5.-

The shell III of the modified form of belt driven multi-stage gyratory crusher has a plurality of ports or openings H0 therein opening into the non-crushing zone H0 between the first and second crushing stages of the crusher. In the drawings only one of the openings H0 is shown, but it is to be understood that any number of them may be provided, depending proportionate size to provide a two-stage or multi-stage crusher and a gyrating conveying surface I00 is provided for conveying and distributing the crushed material from the first stage of the crusher to the inlet of the second stage of the crusher. The concave I 01 of the second stage of the crusher is not shown as adjustable, but the concave I00 of the first stage of the crusher is adjustable.

The adjustment of the size of the final discharge IIO of the crusher and consequently the size or the final product is regulated by adjustment of the crushing head assembly, comprising the gyrating shaft I00, cone I00 and the crushing upon the requirements of each individual machine.

The openings or hand holes H0 serve a number of functions or purposes. That is, they permit the obtaining of a sample of the material being crushed as it is discharged from the first stage so as to enable the operator to mine the various sizes of product being produced by the first stage or by the stage of the crusher at the discharge of which the openings H0. Then also. these hand holes or ports permit removal, man- 1 enter the non-crushing zone,

ually, of all loose material or product being crushed which has failed to enter the succeeddetering stage in instances where the crusher has stopped due to sudden power cut-off or other causes, and they permit removal of any foreign material which has passed the preceding stage and is of such shape or size that it cannot enter and pass through the succeeding stage.

These hand holes or openings also serve the function of permitting an operator to determine whether the volume of material discharged from great to be accomthe preceding stage is too in inmodated by the succeeding stage, in that stances where an excess amount of material is being delivered by the preceding stage some of this material, which can not be taken by the succeeding stage, will flow out 'of the openings H8, which clearly indicates to the operator that there is an excess volume of material passing through the preceding stage and that this preceding stage requires adjustment oi the product being crushed between stages.

In Figure 14 the opening H8 is shown as closed by a pivoted closure flap lit. L-lowever, if it is desired this closure flap may be eliminated and the openings left open to the exterior of the casing at all times,

in accordance with the provisions of the patent statutes, 1 have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiments thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other means.

aromas ward, a stationary frame surrounding the gyrating shaft and comprising an annular portion of substantially constant diameter for each stage, said annular portions being of increased diameter in succeeding stages from top to bottom and joined with each other by outwardly extending ledges, annular grooves provided in the inner sides of said ledges, a ring shaped concave surrounding each crushing head and being spaced from its corresponding annular frame portion, said concaves being adjustably suspended from the ledges of the frame and having their tops extending into and cooperating with the grooves to prevent ingress of dust and crushed particles into the space between each concave and its corresponding annular frame portion, and means for holding each concave in. adjusted position located in the space between each concave and its annular frame portion, said holding means closing the bottom of the spaces whereby dust and crushed particles are excluded.

3. in a gyratory crusher, a gyrating shaft, a substantially conical crushing head on said shaft, a stationary frame comprising an annular portion of substantially constant diameter surrounding said crushing head, said frame provided with a ledge extending inwardly from said constant diameter portion and having an annular groove in its inner side, a ring shaped concave surrounding said crushing head and being spaced from said annular frame portion, said concave adjustably suspended from said ledge and having its top extending into and cooperating with said groove to prevent ingress of dust and crushed What i claim as new and desire to secure by k Letters Patent of the United States is:

i. in a gyratory crusher, a stationary trams, a plurality of crushing heads of progressively larger diameters mounted on a. gyrating shaft, each crushing head surrounded by a suitable stationary concave cooperating therewith to form a tapering crushing zone and so as to form definite crushing stages so designed and constructed that the material to be crushed passes through the crushing stages in sequence and having the active discharge areas of all stages proportioned to pass an equal quantity of material in an equal interval of time, said crusher having a non-crushing area between the adjacent crushing stages and each crushing stage discharging through its corresponding non-crushing area into the succeeding crushing stage, and means adjustably connecting the concave of the initial crushing stage of the crusher to said frame forvertical adjustment of the concave relative to the crushing head whereby the quantity of material crushed by the crusher in a given period of time and the size of the materialv may be varied, said means comprising a wedgeshaped member engaging the non-crushing back of the concave and said stationary frame for moving the concave upon movement of the wedge, and adjustable means connecting the wedge and stationary frame.

2; In a multi-stage gyratory crusher, a gyrating shaft, a number of crushing heads mounted on said shaft, said heads being of increasing diameter from stage to stage from the top downparticles into the space between the concave and annular frame portion, and means for holding said concave in adjusted positions located in the space between the concave and the annular frame portion, said holding means closing the bottom of the space whereby dust and crushed particles are excluded.

4. In a multi-stage gyratory crusher, a. gyrating shaft, a plurality of crushing heads mounted on said shaft, said heads being or increasing diameter from the top downward, a ring shaped concave surrounding each crushing head, means for vertically and independently adjusting each concave, and means movable independently of the concaves for circumferentially supporting and locking each concave in adjusted position.

5. in a multi-stage gyratory crusher, a gyrating shaft, a plurality of crushing heads mounted on said shaft, said heads being of increasing diameter from the top downward, a ring shaped concave surrounding each crushing head, means for vertically and independently arfiusting each concave, and means movable independently of the concaves for circumferentially supporting and locking each concave in an adjusted position, a frame surrounding said gyrating shaft, crushing heads and concaves, said frame provided with means for preventing crushed particles from getting behind the concaves and the independently movable concave supporting and locking means.

6. A gyratory crusher having two or more crushing heads of progressively substantially larger diameters mounted on a gyrating shaft, each crushing head surrounded by a suitable stationary concave so as to form definite crushing stages and having every part of, the crushing surfaces of each crushing stage of a larger diameter than any part of the crushing surfaces of the preceding stage, and so designed and constructed that the material to be crushed passes through the crushing stages in sequence from the smallest crushing heads of progressively substantially larger diameters mounted on a gyrating shaft, each crushing head surrounded by a suitable stationary concave so as to form definite crushing stages and having every part of the. crushing surfaces of each crushing stage of a larger diameter than any part of the crushing surfaces of the preceding stage, and so designed and constructed that the material to be crushed passes through the crushing stages in sequence from the smallest diameter stage to the next larger one, and having the active discharge areas of all stages proportioned to pass an equal quantity of material in an equal interval of time, a stationary frame surrounding said concaves, means for vertically and independently adjusting each concave relative to the frame, and separate means movable independently of the concaves for continuously and circumferentially supporting each concave, said stationary frame'comprising out wardly extending ledges provided withrecesses in their inner surfaces receiving the upper ends of said concaves, said recesses being of such depth that in no adjusted position will the upper edges of the concaves be out of the respective recesses. V 8. In a multi-stage gyratory crusher, a plurality of concaves, a stationary frame surrounding said concaves and provided with outwardly extending ledges, means for vertically and independently adjusting each concave, and wedge means engaging the stationary frame and concaves and movable independently of the concaves for continuously and circumferentially supporting each concave. said outwardly extending ledges being provided with recesses receiving the upper ends of the concaves and said wedges fitting snugly between the concaves andthe frame at the bottom of the concaves whereby dust and crushed particles will be excluded from between the concaves and the wedges and the frame.

9. In a gyratory crusher, a stationary frame, a plurality of crushing heads of progressively larger diameters mounted on a gyrating shaft, each crushing head surrounded by a suitable stationary concave so as to form definite crushing stages so designed and constructed that the materialto be crushed passes through the crushing stages in sequence and having the active discharge areas of all stages proportioned to pass an equal quan' tity of material in an equal interval of time, said crusher having a non-crushing area between the adjacent crushing stages and each crushing stage discharging through its corresponding noncrushing area into the succeeding stage, and concave adjusting means connecting the concave of the initial crushing stage to said frame whereby the concave may be adjusted to vary the quantity of material crushed in said stage in any given time and the size of the material crushed may be varied, said adjusting means including wedge-shaped members between the concave and stationary frame and constructed and arranged whereby the pressure exerted against the .concave by the material being crushed will cause a wedging action of the adjusting means on the concave to bind it in its adjusted position against accidental movement relative to the frame.

10. In a gyrating crusher having a plurality of crushing stages formed by crushing heads mounted on a common gyrating shaft and cooperating with stationary concaves to form definite crushing stages, a supporting frame, means connecting said gyrating shaft to said frame for supporting the shaft and to provide adjustment thereof to regulate the size of the discharge area of the final stage of the crusher, means adjustably supporting the concave of the first of said stages to permit adjustment of the size of its discharge opening independent of adjustment of the size of the discharge of the final stage, said means comprising a wedge-shaped member engaging the non-crushing back of the concave and said stationary'frame for moving the concave upon movement of the wedge, and adjusting means connecting the wedge and stationary frame.

SHELDON S'I'EARNS.

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