US2996261A - Feed and discharge screen structures for rock crushing apparatus - Google Patents

Description

Aug. 15, 1961 M. PICALARGA 2,996,261

FEED AND DISCHARGE SCREEN STRUCTURES FOR ROCK CRUSHING APPARATUS Filed July 18, 1958 4 Sheets-Sheet 1 [Mien 70A WHRCELLU fiC'ALARGA b M5 060;

Aug. 15, 1961 TM. PICALARGA 2,996,261

FEED AND DISCHARGE SCREEN STRUCTURES FOR ROCK CRUSI-IING APPARATUS Filed July 18, 1958 V 4 Sheets-Sheet 2 /MVEA/ro& Mme ELLO Z04 LARcTn Aug. 15, 1961 M. FICALARGA- FEED AND DISCHARGE SCREEN STRUCTURES FOR ROCK CRUSHING APPARATUS 4 Sheets-Sheet 3 Filed. July 18, 1958 VENTM NARCELLO 7/ 04 LAM! Aug. 15, 1961 M. PICALARGA 2,996,261

FEED AND DISCHARGE SCREEN STRUCTURES FOR ROCK CRUSHING APPARATUS Filed July 18, 1958 4 Sheets-Sheet 4 United States Patent 2,995,261 FEED DISCHARGE STRUQTURE-S FOR ROCK GRUSHING APPARATUS Marcello Picalarga, Campagn'anb di Roma, Italy Filed July 18, 195 8,,Ser. No. 749,436 6"Cl ai'ms. (Cl. 141- 77) The present invention relates generally to the manufacture of rock crushing apparatus and similar machinery employed for reducing rocks and" stones to chip and gravel form for use in road building, paving operations;

etc.

More particularly, the present invention has reference to feed and discharge screen structures for machines or apparatus of the kind described In this connection, the present application is a continuation-impart of my co.- pending application Serial No. 392,831, filed November 1'8, 1953, now Patent No. 2,921,750;

In that application, there is disclosed and claimed a complete rock crushing apparatus, including fixed and movable jaws between which the material to be crushed passes, said jaws being adapted, byreason of a novel, particularly effective interrelation of the several components of the machine, to reduce the raw material. to chips or gravel of a selected size.

In the parent application referred to above, the ma.- chinery is illustrated in one form as incorporating both an overhead or feed screen assembly, through which. the material passes en route to the jaw structure, and a lower, discharge screen assembly receiving the crushed material. Said screen assemblies are movable, and movement is imparted thereto by reason of connections which the assemblies have to select, movable components of the jaw means. The screen assemblies, thus, in the application referred to have a predetermined, cycling movement bearing a direct relationship to the cycle. of operation of the jaw means.

In the present application there is illustrated the apparatus shown in the above-referred-to application. of which the present application is a. continuation-in-part,. that is to say, the present application includes an illustration and description of the complete machine includingv the screen. assemblies. The claims of the present application, however, are limited to a construction ineluding the. screen assemblies, that is, to a construction including a feed and discharge structure for: crushing machines. The description of various components, that do not in. and of themselves comprise part of the screen assemblies, has been included herein solely for the purpose of showing the particular mounting of the screen assemblies, the operational characteristics thereof, and the manner in which said screen. assemblies are timed. for operation in relation to the timed or cycling operation of the jaw means. 7

In this connection, one important object of the present invention is to provide feed and discharge screen structures. in coacti ve relation to a movable jaw means, with the linkage. of the movable jaw means to the screen as semblies. being such that there are a specifically predetermined path and timing of movement of the screen assemblies relative to the movable jaw means; and vice versa. It is proposed, in this regard, that said prede-- termined path and timing of the screen' and jaw motions be such as to provide a vastly improved rate and manner of feeding the raw material to the jaw structure; a: preseparation of said raw materialso as to cause only material above a predetermined size to be fedbetween the jaw means with remaining material by-passing; the jaw means completely; and a particularly effective man ner of removing from; the apparatus material that has been reduced by the jaw means to. a predetermined Patented Aug. 15, 1961 smaller size, or that has by-passed the jaw means reason of having already been ofsaid smaller size;

Another important object is toprovide feed and dis charge screen or sieve devices for rock crushing apparatus having a specifically improved, novel form, mount in g, and mot-ion of the respective screens.

By way of background, it may be noted that crush ing equipment for the production of gravel and similar comminuted substances, having screen arrangements for the material which leaves the crusher is, of course, wellknown in and of'itselt. In such equipment, the screens are soarranged that the material is separated according to the size of the pieces of the material. It. is customary toprovide afeeder device for the return to the crusher of pieces that were not reduced to a sufiiciently small size on their initial pass through the machine.

Crushing machines of the character described are equipped with swinging screens in many instances, which screens are driven through their pivotal motion fromv the same source of power, or prime mover, that is used to drive the crusher jaws. The drive of the screens generally employs a connecting arrangement or transmission that may" include a belt, cable, or chain type of driving connection. Aninstallation of this type, however, requires generally speaking, a relatively high overall elevation of the various components of the machine. Further, such an installation necessitates a various additional driving components or elements required in the transmissionof. power from the drive mechanism of the crushing appa ratus to the screen assemblies. This tends to heighten the possibility of breakdowns, both of the crushing and the screening equipment.

In accordance with the present invention, it is proposed to construct crushing apparatus for the production of gravel, chips, and the like, with screen structures drivenin such a way as to eliminate the drawbacks or deficiencies which have been described above and which have been found in machinery already in use. To accomplish this desirable end, I provide screen structures, for crushing machines of the kind referred to, which are driven directly by the movable crushing jaw of the machine, that is, there is required merely a driving connection from the power source to the movable crushing jaw, with the movable crushing jaw becoming, thereafter, a drive. link or motiontranslating device having a direct driving connection to the overhead and discharge screen structures.

Thus, in carrying out the present invention it is proposed to eliminate any need for mechanism generally employed for transmitting power required for the screen motion. It is further proposed, by elimination of said: mechanism, to permit screens to be installed below the jaws of the crusher, thus saving considerable space and, at the same time, reducing to a considerable degree the cost of manufacture of the machine.

Since the movement of the jaws is transmitted directly; to the screen-equipment, it is advantageous in carrying out the present invention to construct the crushing means in a manner such that the movable crushing jaw, at its lower end, is moved by an eccentric shaft, with the upper part being pivotallyconnected to a link which is in turn pivoted upon the housing;

As a further improvement in screen assemblies of the character described, it is proposed in accordance with the present inventiontoprovide anotherformof-ife'ed or inlet screen structure, used for separating chips that are con-- tained in the raw material from larger pieces found in said raw material and required to be supplied to the crusher: In this improved form, the feed or inlet screen is fastened in an inclined position above the crusher to a suitable frame, that is connected both" ends of the; movable jaw structure, thus to be subjected to'or'be otherwise given. theamotion of both: ends oh the. movable structure. At its rear or intake end, the feed screen has a rigid connection to the lower end of the movable crushing jaw, so as to have a motion duplicating that of the lower end of the movable jaw, that is, travel in a circular path about a horizontal axis. The delivery end of the screen is pivotally attached to the upper end of the movable jaw to have oscillatory motion therewith about a horizontal axis paralleling the first axis.

Other objects and details of the invention will be ap parent from the following description in which like reference characters designate like parts throughout the several views, and from the drawing, in which: FIG. 1 is a longitudinal sectional view of a rock crushing apparatus equipped with a discharge screen structure formed and mounted in accordance with the invention, on line II of FIG. 2;

FIG. 2 is a top plan view of said apparatus and discharge screen structure;

FIG. 3 is a view similar to FIG. 1 showing a modified construction wherein the rock crushing apparatus is equipped with both a feed screen structure and a discharge screen structure, interconnected for conjoint operation;

FIG. 4 is a longitudinal sectional view of a rock crushing apparatus, equipped with another form of interconnected feed and discharge screen structures.

- FIG. 5 is an enlarged detail, vertical sectional view of the connection of the feed and discharge screen structures to the movable jaw means of the apparatus, on line 55 of FIG. 4;

FIG. 6 is an enlarged sectional view showing the connection of the suspension rod of the discharge screen structure to the main frame of said structure, said view being taken substantially on line 6-6 of FIG. 4;

' FIG. 7 is a horizontal section substantially on line 7-7 of FIG. 4, on the same scale as FIG. 4; and

FIG. 8 is an enlarged, transverse sectional view through the jaw means of the apparatus, taken substantially on line 88 of FIG. 4.

Referring to the drawing in detail, the apparatus shown in FIGS. 1 and 2 will be described herein substantially in its entirety, so as to obtain a full understanding of the operational and structural characteristics thereof, thus to in turn promote a better understanding of the form, mounting, and operational characteristics of the screen structures, especially in relation to the cycle of operation of the jaw means.

. Thus, the apparatus of FIGS. 1 and 2 includes a stationary housing 1 of approximately rectangular form including a front wall 2, rear wall 3, and side walls 4 and 5, all rigidly connected and extending upwardly from a heavy, horizontally disposed, generally rectangular base. The rear wall is integrally provided with reinforcing ribs 6, 7 (see FIG. 1) and of course additional ribs or strengthening means can be provided on the other walls.

The housing is formed open at the top, whereby to receive the raw material that is to be crushed. Further, the housing is formed open at the bottom thereof, in order to facilitate the discharge of the material after the same has been broken or crushed in a manner to reduce the material to pieces of the desired, smaller size.

- Spaced closely from the front wall 2, and extending transversely of the housing above the front wall is a stationary, horizontal shaft 8, the ends of which are engaged in the side walls 4, 5. Shaft 8 extends through a transversely, horizontally extending sleeve 9 integrally formed upon the upper end of a thick, heavy support plate 10 of a fixed jaw 11. Jaw 11 and plate 10 together define a fixed jaw structure.

The fixed jaw 11 is in confronting relation to a movable crushing jaw 12, and the opposed, material-engaging faces 11' and 12' of the jaws are ribbed or toothed in a manner described in full detail in my co-pending application, Serial No. 392,831.

r The support plate 10 can pivot, together withthe fixed jaw 11 that is rigidly secured thereto, about an axis de-.

fined by the horizontal shaft 8, but said pivotal movement is prevented by the opposing action of a coil spring 13 and an adjustable member 14. These components have also been described in full detail in my co-pending application, Serial No. 392,831. For the purpose of the present application, it is sufiicient to note that the member 14 comprises a rectangular plate 61, engaged by a notch formed in the adjacent surface of the plate 10. The opposite edge of the plate 61 extends into a channeled casing that extends horizontally, transversely of the front wall 2 in a transversely disposed recess 63 formed in said front wall.

Plate 61 is designed to oppose pressure tending to shift the fixed jaw structure toward front wall 2 during normal operation of the machine, and it will be noted that the plate in eifect constitutes a rigid spacer means between the front wall and the fixed jaw structure. However, the plate is adapted to bend or yield when certain materials that resist crushing, as for example, pieces of iron and the like, accidentally move into the crushing gap 31.

Meanwhile, the coil spring 13, tending to expand, exerts force upon a fixed jaw structure tending to move the same toward the front wall 2, since the spring acts upon a bolt 15 which is pivotally connected at 16 to the fixed jaw structure and which passes loosely through an opening formed in the front wall 2.

The previously mentioned movable breaking jaw 12 is rigidly mounted upon a support plate 18, strengthened by i longitudinal ribs 19 integrally formed upon the back surface thereof. Jaw 12 and support 18 together constitute what may be appropriately termed a movable jaw structure. The support 18 is provided, near its lower end, with a sleeve or stub 20 through which extends an eccentric shaft 21 carried by roller bearings 22. The eccentric shaft guides during the raising and lowering of the movable jaw relative to the fixed jaw in its motion toward and away from the fixed jaw. The links are pivotally connected at one end to the upper end portion of the movable jaw support 18 by means of a pin 27, and at their other ends are pivotally connected to the ears 26 by means of a pin 29 journaled in ball bearings 28 and 30 respectively. The ears 26 are fixedly secured to the upper end wall of the back wall 3.

During the motion of the movable jaw, which is effected by the eccentric shaft 21, the links swing in an angle of about 45 degrees to the vertical. The guidance and actuation of the movable support 18 by the lower eccentric shaft and the upper guide links have the result that the width of the gap 31 in which the stones are broken varies increasingly from top to bottom. This increase in the movements of the movable breaking jaw relative to the fixed jaw leads to the production of a more uniform ballast, and to a more uniform shape than has heretofore been obtainable with known stone breaking machines.

' The movable support 18 is continuously pressed, by means of a strong helical spring 32, toward the fixed jaw 11. Spring 32 abuts at one end against the rear wall 3 and at its other end abuts against the back surface 33 of the movable jaw structure. The tension of the spring can be adjusted to a selected extent through the medium of a threaded bolt or stud 34, which is threadedly engaged in a sleeve 35 and which terminates at its inner end in an abutment or support plate 34 for the spring 32. Spring 32 is tightened, that is, placed under increased compression when the movable jaw structure moves away from the fixed jaw structure. The spring expands when the movable jaw moves toward the fixed jaw during the actual crushing .of material in the gap 31. The spring thus acts as an equalizing means, equalizing the load of the eccentric shaft, in a manner such as to result in a reduction of the power that would otherwise be required for the crushing operation.

In FIGS. 1 and 2 there is shown a first form of screen structure according to the present invention. In these figures of the drawing, there is provided only a discharge screen structure, which structure is adapted to receive the gravel dropping out of the crushing gap 31. In the form shown in FIG. 3 there is a discharge screen structure in combination with a feed screen structure, withthe latter structure being adapted to effect a preliminary screening or separation of the raw material.

The crushed material gravitating from gap 31 falls onto a discharge screen structure generally designated at 40. This includes an elongated, generally planiform screen support frame :17 declining forwardly from the jaw structures of the device through an opening 74 in Wall 2 as shown to particular advantage in FIG. 1. Frame 17 is of a width substantially coextensive with the width of the jaw means, as will be noted from FIG.

2. Supported upon the frame '17 and removably, fixedly connected to said frame in end-to-end relation over the full length of the frame, is a series of screens designated 65, 66 and 67, respectively, each of which may comprise a plate having a plurality of perforations therein, said perforations being of a selected size.

The first screen 65, which is that onto which the gravel 43 falls directly from the crushing jaws, has extremely small apertures, so that only dust 44 can pass through said apertures.

The gravel now travels to the screen 66 which may be termed the intermediate screen. The apertures or perforations of this screen are larger than those of the first screen but are still quite small so as to permit the passage only of gravel 45 of a prescribed, small size.

The material-traveling along the screen structure 40 to the lower, discharge end thereof now passes to the screen 67. Here the larger pieces, designated at 46, are permitted to pass through the openings of the screen, since the openings of the last screen are of substantial size.

At its intake end, the discharge screen structure 40 is pivotally connected to the lower end portion 20 of the movable jaw structure, by means of a pin 47. Therefore, the discharge screen structure at its inlet has a movement duplicating exactly the movement of the portion of the movable jaw to which it is directly, pivotally connected. The inlet end of the discharge screen structure thus has up-and-down movement, as well as movement in the direction of its own length. This combination of movements has been found to produce a par ticularly effective screening action, that promotes the steady, uniform discharge of the material over the full length of the screen structure, with the material being distributed evenly and to a comparatively uniform depth over the whole width and length of the screen. Further, said combined movements of the discharge screen structure have a desirable effect of imparting a force to the material flowing therealong effective to drive the material through the apertures of the several screens.

Through the appropriate inclination of the discharge screen structure 40 in relation to a horizontal plane, the continuous flow of the material to be screened is assured from the delivery point, that is, the point directly below the crushing gap 31, over the full length of the series of screens 65, 66 and 67, until said material reaches and passes off the discharge point.

The angle of inclination must be so regulated that the vibratory action imparted to the mass of gravel will not exercise any disturbing influence upon the crushing action of the jaw 12. This is accomplished in the presentinstance by adjustment of a connection which the 6 screen has at its discharge, lower end to an overhead support bracket 49.

The support bracket 49 is fixedly secured to and projects forwardly, horizontally from the front wall 2. In actuality, there are two brackets 49 transversely spaced in a common horizontal plane. In close proximity to the front, distal ends of the brackets 49, suspension rods 50 are pivotally connected at 51 to said brackets. The suspension rods, at their lower ends, are pivotally connected at 52 to the lower, discharge end of the structure 40. One or more inclined struts 68 can be provided to take up the stresses imposed by the shaking sieve or screen upon the bracket 49 through the articulated or suspension rods 50.

The suspension rods support the discharge end 48 of the screen 40 at a slightly lower level than the intake end 42 of said screen, in order to allow a slow descent, by gravitational action, of the crushed material toward the discharge end of the screen. .In this connection, the support means for said discharge end 48 described above is so designed as to alter as little as possible the motion imparted to the intake end 42 by the co-opera-ting eccentric shafts 21 and links 25.

Referring now to FIG. 3, in this form of the invention, the discharge screen structure has been generally designated 40' and includes a frame 53 analogous to frame 17. Frame 53 is provided with a rearwardly projecting, longitudinal extension 53' coplanar with the portion of the framer53 .that is disposed forwardly of the pivotal connection of the discharge screen to the movable jaw.

The screen structure 40' includes the screens 65, 66, 67 as in the form shown in FIG. 1, having progressively larger size perforations. Thus, so far as the separation and discharge of gravel after crushing is concerned, the form .of the .invention shown in FIG. 3 operates identically to the discharge structure 40 shown in FIG. 1.

In the form shown in FIG. 3, an overhead or feed screen structure is connected to the discharge screen structure 45 for conjoint movement therewith, so that both screen structures are driven directly by the movable jaw structure. In this form of the invention, the extension 53 of the frame 53., which extension comprises parallel, straight, rearwardly extending rails, is pivotally connected to an upwardly projecting frame 54 which can comprise vertically extending members braced by inclined members or struts. Frame54, as will be readily seen from FIG. ,3, thus in effect constitutes a rigid, upstanding support structure projecting upwardly from the extension 53.

Connected to the upper end of the frame '54 is a feed screen structure 55. In this connection, it will be noted that the rails comp-rising the extension 53' are connected, at their rear ends shown at the left in FIG. 3, by a transverse bar 78 which is fixedly secured to and extends between said rails. The open space bounded by the rails and by the member 78 can be utilized wholly or partially for a sloping sheet, not shown, which would collect the crushed material gravitating from the upper shaking sieve or screen 55.

The support frame 54 can be and preferably is formed of a plurality of vertical'bars and cross bars, welded, bolted, and otherwise fixedly secured to both the rails that constitute the extension 53' of the lower discharge screen 40. The vertical members of the frame 54 are connected to side rails 72 of the upper shaking sieve 55.

The upper shaking sieve "55 is supported in such a manner by the frame '54 as to be disposed at an angle of inclination cor-responding to that of the discharge screen structure. The upper and lower screens, thus, are in parallel relation. By reason of the position in which the sieve 55 is supported, it has been found that initially large stones or rocks, roughly broken in a preceding crushing stage in a stone crusher of the usual type, not shown, will be supplied to the crushing gap 31 as shown in FIG. 3. The hole or mesh size of the upper sieve can be so .de-

signed as to separate from the raw material that is to be fed to the crushing gap small pieces 71, which are already of a size and shape corresponding to the desired final product that is to drop out of the crushing gap after being acted upon by the fixed and movable jaws.

In the form shown in FIG. 3, the assembly comprising the lower sieve 40', having the frame '3 and frame extension 53', the middle frame 54, and the upper sieve 55, is carried by the lower sleeve 20 for pivotal movement about a horizontal pin 47 passing through the center of gravity of this assembly. In this manner, said assembly is balanced about the pivot 47 so as to follow closely the movements imparted to said pivot by the coactive motions or actions of the eccentric shaft 21 and links 25.

In order to prevent said assembly from becoming unbalanced by displacements of the varying weights carried on the lower and upper sieves 40' and 55, respectively, spring members 56 or the like can be provided, these comprising coil springs extending generally vertically and abutting at their upper ends against the frame extension 53'. At their lower ends, the springs 56 abut against base plates 57 or the like.

The housing 1, and the above mentioned base plates 57, are provided with passages 74' and 75, respectively for the lower shaking sieve 40 or 40' as the case may be, and for the projecting firame extension 53' of the lower sieve or screen.

Referring now to FIGS. 4 to 8, the rock crushing apparatus, that is, the apparatus including the eccentric, fixed and movable jaw structures, links, etc., is essentially similar to that described and claimed in my co pending application, Serial No. 392,831.

In these figures of the drawing, according to the present invention, the crusher is provided with an inclined feed screen structure 160 adapted to separate from the raw materials that are to be fed between the jaws any chips that are already of a sufficiently small size to permit their passage directly to the discharge screen structure without first passing through the crushing gap. These chips are discharged from the screen structure 160 through a hopper 161 and a curved chute 162, so as to pass directly to the intake end of the discharge screen structure 140. The coarser material 163 falls into the crushing gap, so as to be crushed between the movable jaw 112 and the fixed jaw 111.

The screen 160 is secured to a frame 164, which is connected at its upper end by means of a pin 165 to a projection 166, rigid with and extending upwardly from the movable jaw structure 118. The frame 164 is fixed at its lower end to a projection 167 of the lower hub or sleeve 120 of the movable jaw structure 11 8. In this way the frame 164, and hence the screen 160, is caused to duplicate or follow the rocking movement of the movable jaw structure 118 so as to cause the proper feeding and screening of the material. In other words, the rear or intake end of the screen 160 has a motion identical to that at the lower end of the movable jaw structure 118, and this is true also of the intermediate or mid-length portion of the screen 160. At its forward or discharge end, the screen 164) has a motion identical to that which is imparted to the upper end of the movable jaw structure by the links 125.

Referring now to FIG. 5, a particular, detailed showing of the connection to the projection 167 is here provided. A threaded bolt 169 is screwed into a nut 170 having a lower conical surface 171 engaging in a complementary cavity of the lower rod 172 of the frame 164. At the opposite side of the projection 167, the bolt 169 extends through a sleeve 173 having a conical surface 174 engag ing in a complementary recess of the projection 167.

The frame 142 of the lower screen 140 (corresponding to the frame 17 of FIG. 1) receives and is freely pivoted upon the sleeve 173, being held thereon by a washer 175 biased against the sleeve 173 by the head of the bolt 169.

By'tighten'ing the bolt'169 and the'nut 170, and by thereafter engaging the bolt and nut against relative rotation through the medium of a cross pin 176 extending through the bolt into a groove of nut 170, the rod 172 is tightly clamped against the projection 167. This results from the pressure exerted by the opposed conical surfaces 171 and 174. However, the frame 142, and hence the entire screen 140, may freely pivot or rotate about the sleeve 173.

From this it will be seen that the frame 164, and hence the rear and intermediate portion of the feed screen 160, are lockably engaged with the projection 167 so as to have every movement that the projection 167 will have, including any oscillating movement of the projection 167 as well as the up-and-down motion thereof.

At the same time, however, the front end of the screen has a pivotal connection at to the upper end of the movable jaw, and the discharge screen has a pivotal connection to the lower end of the movable jaw.

Referring now to FIG. 6, there are here shown the details of a connection of a suspension rod 150 to the outlet or discharge screen 140. As will be noted, a pin 177 extends through the opening of an ear or bracket 17 3 rigid with and projecting upwardly from the frame 142 of screen 140. Pin 177 passes through the lower end of suspension rod 150.

. The pin 177 projects beyond the suspension rod 150, and on its projecting end extends through a coil, compression spring 179, which is abutted against a washer 180 held in place by a cotter pin 181.

Washers 1 82 are used as spacers at opposite sides of the suspension rod 150, to provide relative rotation of the various connected components illustrated.

The type of suspension illustrated is particularly effective because of the movement obtained. It is to be noted, in this connection, that the fixed overhead support arm or bracket 149 has a plurality of openings 151, 151, 151", etc. any of which may receive a connecting pin that passes also through the upper end of the suspension rod 150, thus to provide adjustments in the inclination of the discharge screen 140.

Referring now to FIGS. 4 and 7, it will be seen that certain improvements in the jaw crushing assembly are here shown. In this form, as distinguished from the form shown, in FIG. 1, there are two springs 132 for the absorption of the impacts and for recovering the pushing force. This has been found to obtain a better stress distribution. Referring to FIG. 8, as will be noted there is here shown an additional improvement in the rock crushing apparatus, separate and distinct from the screen structures. In this figure there is shown a wedge device generally designated at 114 for adjusting the position of the fixed jaw structure 110. The wedge device 114 includes two flat, transversely and horizontally spaced members 183 each of which hasa smooth inner edge 184 engaging in a complementary recess provided in the back surface of the front wall 102 of the crusher. The outer edge 185 of each member 183 is beveled, at an angle of preferably 45 degrees, the edges 185 of the respective members 183 being oppositely beveled and bearing against correspondingly beveled or inclined surfaces of the fixed jaw structure 110.

The two members 183 are connected by a suitable boltlike rod 186 extending between the same and passing through bores provided in the members 183. The members 183 can be moved longitudinally of the rod 186 toward and away from each other, when said rod is tightened or unloosened, respectively, so as to either raise or lower, whichever is. desired, the fixed jaw structure 110, thus to adjust the gap between jaws 1 11 and 112.

In other Words, the surfaces 185 comprise cam surfaces which, when moved toward each other in a horizontal path extending transversely of the front wall, exert a biasing action against the complementary cam sura edaei faces of the jaw 110, tending to shift said jaw 110 about the pivot represented by the support bar 108 of said jaw 110. If the members 183 are moved toward each other, the jaw 110 is caused to move toward the jaw 112, traveling clockwise in FIG. 4 about the bar 108. Movement of the jaw 110 away from the jaw 112 results when the members 183 are moved away from each other. In my position to which the fixed jaw is moved, it will be maintained against movement toward the housing wall 102, since the members 183 at all times constitute rigid spacers between the jaw 110 and the wall 102.

The rod 186 is also a safety device, in that it is adapted to shear under certain circumstances to deliberately permit movement of the jaw 110 toward the housing 102. In the event a hard material such as iron or the like, falls into the crushing gap, the fixed jaw structure, forced under the pressure of the crush-resistant material against the members 183, biases said members away from each other by a cam action and shears the rod 186 by tensile stress in correspondence with a predetermined stress value, said rod 186 having suitable sizes and hence suitable tensile stresses for this purpose.

It will be apparent to those skilled in the art that many modifications and alternations of the structure shown and hereinbefore described can be made without departure from the essence and spirit of my invention which for that reason shall not be limited but by the scope of the appended claims.

I claim:

I. In a crushing machine including a frame, a fixed jaw, a movable jaw, a link member pivotally connected with its one end to the upper part of said movable jaw and with its other end to said frame; and an eccentric shaft passing through the lower part of said movable jaw so as to actuate the latter rotatably, the combination of a screen assembly comprising a discharge screen having a material receiving end and a delivery end and being located below a gap formed by said jaws, said discharge screen slanting downwards from said receiving to said delivery end, said receiving end being directly and pivotally connected to said lower part of said movable jaw below said eccentric shaft so as to travel in a complete circular path about a horizontal axis, link means movably connected to a stationary part, said discharge screen being connected to said link means for limiting oscillation of said delivery end to a predetermined arcuate motion about said lower part of said movable jaw in such a manner that the vertical component of the rotary movement has a maximum at the material receiving end of the discharge screen where the variety in the sizes of the material is greatest, said vertical component decreasing towards the delivery end of the screen, a second screen structure having a delivery end disposed directly above the crushing jaws for feeding the materials to be crushed to said jaws, and a framework rigidly connecting said second screen structure to the receiving end of the discharge screen structure, so as to hold said second screen structure permanently substantially parallel to said discharge screen whereby said second screen structure will be moved by said lower part of said movable jaw conjointly with said receiving end of the discharge screen structure through a cycle duplicating that of said receiving end of the discharge screen structure.

2. A screen assembly as in claim 1 wherein said framework comprises a longitudinal extension projecting from and rigid with said receiving end of the discharge screen structure, and a member fixedly secured to and extending upwardly from said extension, the second screen structure being fixedly connected to the upper end of said member.

3. A screen assembly as in claim 2 wherein said extension declines in a direction toward said receiving end of the discharge screen structure and constitutes a chute 10 v along which materials may gravitate into confluence with materials falling onto the discharge screen structure from the jaws, the second screen structure including a screen upstream from the delivery end of the second screen structure and disposed above said extension, said screen being of a mesh such that raw materials of a predetermined size requiring no crushing will pass through said screen to gravitate to the extension and thence into confluence with materials crushed between and falling from the jaws.

4. In a crushing machine including a frame, a fixed jaw, a movable jaw, a link member pivotally connected with its one end to the upper part of said movable jaw and with its other end to said frame, and an eccentric shaft passing through the lower pant of said movable jaw so as to actuate the latter rotatably, the combination of a screen assembly comprising a discharge screen having a material receiving end and a delivery end and being located below a gap formed by said jaws, said discharge screen slanting downwards from said receiving to said delivery end, said receiving end being directly and pivotally connected to said lower part of said movable jaw below said eccentric shaft so as to travel in a complete circular path about a horizontal axis, a link pivoted to a stationary part, said delivery end of said discharge screen being articulated to said link so as to oscillate in an arcuate motion whereby the vertical component of the rotating movement has a maximum at the material receiving end of the discharge screen where the variety in the sizes of the material is greatest, said vertical component decreasing towards the delivery end of the screen, said screen assembly further comprising a feed screen structure including a feed screen having a material receiving end and a material delivery end located above the gap formed by the jaws to deliver material thereto for crushing between the jaws, said feed screen slanting downwards from said receiving to said delivery end, means for pivotally connecting said delivery end of the feed screen to the upper part of said movable jaw and means rigidly connecting the lower part of said movable jaw with the material receiving end of the feed screen.

'5. A screen assembly as in claim 4, wherein the lastnamed connecting means is rigidly connected to the lower part of said movable jaw at the point at which said receiving end of the discharge screen is pivotally connected to said lower part.

6. A screen assembly as in claim 4, wherein the lastnamed connecting means has mounted thereon below the feed screen and intermediate its ends a chute slanting toward the receiving end of the discharge screen, said chute receiving from the feed screen materials of sufiiciently small size to require no crushing and transporting the latter materials by gravity to the receiving end of the discharge screen.

References Cited in the file of this patent UNITED STATES PATENTS 1,798,433 Rigdon Mar. 31, 1931 2,631,785 Bogie Mar. 17, 1953 FOREIGN PATENTS 15,749 Great Britain Nov. 17, 1887 31,070 Germany Apr. 15, 1885 479,123 Italy Mar. 18, 1953 731,181 France May 24, 1932 743,131 France Jan. 6, 1933 766,320 France Apr. 9, 1934 815,290 Germany Oct. 1, 1951 868,256 France Sept. 22, 1941 OTHER REFERENCES Rock Products, October 1947, page 83, Vibrating Grizzly.

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