US3029947A - Screening device - Google Patents

Description

April 17, 1962 A. J. ROUBAL SCREENING DEVICE 2 Sheets-Sheet 1 Filed June 8, 1959 April 17, 1962 A. J. ROUBAL SCREENING DEVICE 2 Sheets-Sheet 2 Filed June 8, 1959 Aqkkome/y,

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This invention relates generally to screening machines or apparatus for use in connection with screening ofmaterials and like operations. More particularly, this invention relates to a gyratory screen machine of the four bearing type wherein the gyrating screen body is both supported and stabilized by resilient mounts strategically interposed between outer bearing housing extensions and other parts of the structure to provide a device in which the vibrations resulting from the operation thereof are substantially completely isolated from the building in which the screen is mounted.

For purposes of this description, a four bearing screen may be considered as being in part a conventional two bearing screen having two running shaft projections extending outside of its balance wheels. Such a two bearing screen, however, becomes a four bearing unit because these shaft projections are journaled into outer bearings which thus carry the entire weight of the screen. In prior art machines, as exemplified by Parks, US. 2,212,550, these outer bearings in turn are carried on a stationary frame which rests on or is suspended from the building floors.

In order to keep the screen on its proper angle, it is necessary to stabilize the body. Screens have heretofore been stabilized by means of springs placed near each corner of the screen body. Such a screen body can be perfectly balanced under no load conditions so that the axis of gyration exactly coincides with the center of the outer bearings and no vibrations will go into the building.

When, however, the screen weight changes due to the nonuniformity of loading during operation, or when materials stick to the deck, or when changes occur in the weight of the screen cloth, the screen becomes unbalanced. Since, in the screens of the prior art, the outer bearings of the screen are mounted rigidly to the supporting frame which is, in turn, rigidly secured to the building, the amount of out of balance will be transmitted directly to the building. When this occurs in a building which has an extra amount of steel, the screen will lose only a small amount of throw. However, when the building steel is no heavier than that required to carry the dead-weight load, as might be normally expected, the screen will lose a considerable amount of throw and the building will vibrate an amount almost equal to the loss of throw of the screen.

The present invention is predicated upon my discovery that, by resiliently mounting the screen body directly to the outer bearing housing and then resiliently mounting the outer bearing housing directly to a supporting structure, substantially all of the vibrations resulting from an out-of-balance condition in the screen body will never reach the supporting structure but instead will be ab-I sorbed directly in the amounts which, when made according to my later description, possess a unique propensity and efiiciency to absorb vibrations. Thus, in the screen of the present invention, as will be more fully de-- scribed, each outer bearing is carried in a housing having a pair of arms extending oppositely therefrom and each arm is supported by two sets of resilient mounts, one set of mounts being carried by the bearing housing arm near each corner of the screen body and resiliently connecting the body to the arm, and the other set of mounts resiliently connecting the arm to a stationary.

supporting structure. With this arrangement, only four Patent mounts are required to support the entire live weight of the screen relative to the building and only four more mounts are required to stabilize the screen body.

When the amount of eccentricity machined in the shaft is equal to one-half of the screen throw and the screen is then properly balanced, the outer hearings will have no motion while the screen body has its full circular motion. Consequently, during operation of the screen, the four mounts which are placed between the outer bearing housing arms or extensions and the stationary supporting structure (which may be considered as part of the building) do not vibrate while the four sets of mounts which resiliently connect the screen body to the outer bearing arms do vibrate but are isolated from the building. And this is true even when the screen has a fairly large load of material.

If the screen is excessively overloaded, the throw of the screen will be reduced and the outer bearing arms will take on a slight circular motion. Under this condition, the screen is out of balance and some vibrations will be transmitted to the building. However, even under these extreme conditions, the shock load transmitted to the building is substantially minimal as a result of the requirement of my design that such load pass through the stabilizing mounts, the arms and the supporting mounts before it ever reaches the structure. Because of the large deflections initially placed in the mounts by the screen dead weight in accordance with this invention, substantially all of the shock is absorbed in the mounts with the result that little, if any, ever reaches the supporting structure. In my arrangement, it thus becomes apparent that the deflections of the carrying mounts and the body stabilizing mounts become additive.

The carrying or supporting mounts of the screen of the present invention, unlike those of the prior art, are not affected by the screen throw and therefore will give long life. Further, when the unique compression mounts described in my copending United States application, Serial No. 835,744,'filed August 24, 1959, are used with the screen, replacement of the mounts takes considerably less time than has been heretofore possible.

Accordingly, one of the prime objects of this invention is to provide an improved four bearing screen which is completely balanced relative to, and therefore will not cause vibrations in, its stationary supporting structure during normal operation.

Another object of the present invention is to provide a new four bearing screen design in which vibrations of operation are isolated from the stationary supporting structure to which it is mounted by the preoperative static deflection and strategic placement of resilient supporting mounts therein.

Another object of the present invention is to provide a new four bearing screen design in which balance between the screen body and special extensions outreaching from outer bearing housings is obtained by the reaction to the action placed upon a series of novel resilient mounts strategically disposed relative thereto.

, Still another object of the present invention is to provide a new four bearing screen design which, even under severe shock, permits only minimal transmission of such shock to the building in which it is mounted.

A still further object of the present invention is to provide an improved balanced four bearing screenin which the outer bearings remain stationary throughout normal' In the drawing in which like parts bear like numerals throughout the several views:

FIG. 1 is a plan view of a vibrating device embodying the present invention;

FIG. 2 is a side elevation of the device in FIG. 1;

FIG. 3 is a cross section taken along line IlIIII of FIG. 2 showing a stabilizing mount of the type herein contemplated;

FIG. 4 is a cross section taken along line IV-IV of FIG. 2 showing a supporting mount of the type herein contemplated;

FIG. 5 is a side elevation of another vibrating device embodying a variant of the present invention; and

FIG. 6 is a cross section taken along line VI--VI of FIG. 5.

By way of example, one embodiment of my invention is shown in connection with an apparatus for screening materials in which the numeral 11 indicates the stationary base or supporting structure which may consist of a plurality of channel rails 12 or like member carried by appropriate companion resilient gyratory supporting bodies or bearings 31, 32, herein called inner bearings. The drive shaft 30 is continuous and uninterrupted and is provided adjacent its opposite ends with a plurality of journal portions which are mounted within the bearings 31, 32 fitted respectively in the adjoining side walls 19, 20 of the screen body 13 and extend therefrom through suitable inertia controlling means such as flywheels 33, 34 into second bearings 35, 36 respectively fitted in the adjoining gyratory supporting body. Bearings 35, 36 are outboard of bearings 31, 32 and the therefore herein called outer bearings. The axis of the outer bearings is offset from the axis of the inner bearings by the amount of eccentricity in the shaft, for example, one-half of the total throw desired in the screen body.

Each of the outer bearings 35, 36 is enclosed by a suitable outer bearing housing 37, 38 respectively. Each outer bearing housing, for example, housing 37, is provided with a pair of outwardly extending arm portions or extensions 39, 40, the full significance of which will be more fully explained.

One end of shaft 30, for example, the end passing through inner bearing 32, flywheel 34 and outer bearing 36, is provided with a further extension 41 to which is secured a pulley 42 for a driving connection to a source of power. A suitable linkage such, for example, as V- belts 43, connects pulley 42 with driving sheave 44 secured to the drive shaft 45 of a suitable motor 46 mounted adjacent screen frame 13 as on a pedestal 47. As shown, shaft extension 41, that is, the pulley receiving portion of the shaft 30, is concentric with the actual center thereof. Motor 46 may comprise any supports (not shown).

Numeral 13 indicates the screen body or frame which is freely or resiliently suspended from the base 11 and into which a gyratory motion is imparted for effectually screening materials delivered thereto. As shown, the screen body or frame 13 is inclined in the conventional manner to permit the flow of material therethrough and is provided with two screen decks 14, 15 disposed in the usual vertically spaced relationship to each other and comprising a screen cloth 17 and clamping means 18 for securing the cloth 17 to the screen body 13. It is, of course, understood that any desired number of screen decks may be employed according to the exigencies of the operations.

The screen body 13 as shown further includes upwardly extending side plates 19, 20 which reach above the upper screen deck 14 to prevent the lateral loss of material and backing plates 21, 22 which prevent spillage of material at the feed end of the screen. Clamping means 18 are normally attached to the side plates 19, 20. Adjacent the discharge end of the screen, suitable chutes 23, 24 are provided for each deck for directing the flow of the material from the screen deck into a desired continuation 4 of the unit process involved such, for example, as a conveyer, a scrubber and the like.

The means for gyrating the screen body is preferably constructed as follows: the screen body 13 is balanced or supported for gyratory movement midway of its ends on a transverse driving shaft 30 which passes through the side walls 19, 20 of the body 13 and which is supported at its opposite ends in a free floating fashion in and by suit able source of motive power although electrical motors are generally preferred.

Gyration of the screen body 13 is thus readily achieved by the actuation of the motor 46 which, in turn, drives sheave 42 through sheave 44 and linkage 43 whereby gyrating shaft 30 is rotated in bearings 31, 32, 35, 36 and with flywheels 33, 34 to impart gyratory movement to decks 14, 15.

Referring now to the outer bearing housing previously described (considering housing 37 in FIG. 2 as exemplary), each housing is provided with outwardly reaching arms or extensions 39, 40 which, as previously described, extend from opposed peripheral portions of the outer bearing housing 37. Each of the arms 39, 40 extends generally longitudinally of the screen body 13 and terminates adjacent the ends thereof such as is shown in FIGS. 1 and 2. Of course, a like construction is provided on the opposite side of the screen body 13 where arms 39a and 40a extend outwardly from hearing housing 38.

Adjacent the ends of each arm, for example, arm 39, and intermediate the arm and the screen frame 13 is interposed a shear mount 51 which resiliently connects the arm end to the screen frame 13. A like mount 52 is provided intermediate arm 40 and frame 13 adjacent the end of arm 40.

Another pair of resilient mounts 53, 54 are deployed adjacent mounts 51, 52 and outer bearing housing 37 on arm portions 39, 40 respectively in such a manner that one mount is connected between each of the arms and the portion of supporting structure 11 adjacent thereto. Thus, mount 53 resiliently connects arm 39 and supporting structure 11 and mount 54 resiliently connects arm 40 and supporting structure 11. While mounts 53, 54 are shown within the span of mounts 51, 52, satisfactory results are also obtained when one or both of the sets are interchanged. As a matter of preferred design, however, the

mounts will connect to the arms nearer to the ends of the arms than to the outer bearing housing.

Suitable mounts for use in this structure include those especially designed by me and described in my aforementioned U.S. application. Any other of the conventional' resilient mounts, such as those described in Parks U.S. 2,066,362 and the like, may be likewise employed with equal facility in connection with this invention provided the spring assembly, as the mounts are herein called, possesses the facility to be mounted so that mounts 51 and 52 and 51a and 52a, those corresponding thereto on the other side of the device, function to stabilize the screen and mounts 53 and 54 and 53a and 54a, those corresponding thereto on the other side of the device, function to absorb the shock emanating therefrom.

Referring now to FIGS. 3 and 4, representative stabilizing and supporting mounts are shown. The stabilizing mount 52, shown enlarged in FIG. 3, is mounted intermediate screen body 13 and outer bearing housing extension 40 and comprises a mount housing 55 having detachable end plates 56, 57 secured thereto defining a substantially rectangular opening 58 therewith. The outer bearing housing arm 40 is slotted at 59 to provide communication between opposed sections 60, 61 of the mount 52. Each section comprises first and second complementary wedge portions 62, 63 respectively, having a cylindrical wedge portion 64 interposed therebetween to provide a shear mount having opposed surfaces generally parallel to each other. When the sections are engaged as shown so that one (for example 60) is the mirror image of the other (for example 61), a mount 52 is provided which may be readily mounted within the rectangular opening 58 defined by housing 55 and end plates 56, 57 in the manner shown. It has been found, however, that in the purview of the present invention any of the well known conventional resilient mounts may be utilized, adapting the mount housing to conform thereto, provided they still resiliently connect the specified members of my device. Similarly, the slotted opening 59 defined in arm 40 is described merely to exemplify one method of installing the representative modular units and it is not intended to provide a limitation to the present invention.

In FIG. 4, a representative supporting mount 54 is shown comprising arrangement of modular mount sections 71, 72 generally similar to the stabilizing mount except that they have been reversed to provide an angle of incidence between the modular units which is divergent up- Wardly instead of downwardly as in the case of the stabilizing mounts to illustrate another mounting arrangement which may be employed with my device.

In illustrating the supporting mount, I have chosen a variant seating structure for the modular sections. Thus, the bearing arm 46 is provided with first and second oppositely disposed mount seats 73, 74 having a thin (relative to the full thickness of the arm) central wall portion 75 interposed therebetween. Surrounding this portion of arm 40 is a supporting mount housing 76 having a body portion enclosed by detachable end plates 77, 78 and attached to supporting structure 11 in a suitable fashion.

In the embodiment described, the screen body has a circular motion and the outer bearing arms have no motion when the screen is properly balanced. Thus, before connecting the stabilizing mounts 51, 52, 51a, 52a between the arms 39, 40, 39a, 40a and the body 13, the inch-pounds of the complete screen body 13 must be equal to the sum of the inch-pounds of the shaft 30 and the counterbalancing wheels 33, 34, at which time the center of gyration is coincident with the center of the outer bearings. The action which results when the body stabilizing mounts are connected is met with an equal and opposite reaction at the outer bearings. Thus, no movement of the arms takes place.

An important aspect of the present invention thus presents itself in that each outer bearing housing is, as previously described, provided with outwardly extending arms which are, adjacent their respective ends, resiliently connected to the screen body and to the supporting frame by independent resilient shear mounts which are prebiased to provide opposing force moments relative to the locus of the outer hearing. The high static deflection imparted to the several mounts, and the novel coaction of the mounts with the bearing housing arms and their novel arrangement relative thereto, is believed to be an important reason attributing the vastly improved operating characteristics to my screen.

An alternate embodiment of the present invention which is especially suitable for installation where space requires that the screen be suspended from an overhead structure is illustrated in FIGS. and 6. The primary advantage of my construction, namely, that better vibration control can be achieved when the screen is out of balance due to overload or material adhering to the deck, is substantially obtained with this low space variant. In both structures, however, considerably less shock intensity is transmitted to the mechanism bearings, and hence to the buildings when large feed is dropped onto the screen, than heretofore obtained by the structures of the prior art.

Specifically, the embodiment of FIGS. 5 and 6, which as previously stated is especially adaptable for installations where space requirements preclude on-the-floor mounting, comprises a screen body 113 having upper and lower screen decks 114, 115 respectively (formed of end members 116, cloth 117 and clamping means 118, as previously described) and provided with side plates 119,

and backing plates 121, 122 to assure that the treated material passes only to their respective chutes 123, 124. The screen body 113 is provided with a suitable gyrating shaft extending therethrough between inner bearings 131, 132 respectively carried by side plates 119, 120 and extending into suitable outer bearings 135, 136 at each end thereof which are carried by suitable bearing housing 137, 138 in a manner similar to the embodiment shown in FIG. 1.

Each bearing housing, for example housing 137, is provided with outreaching arms 139, 140 extending oppositely from symmetrical portions of the bearing housing and resiliently connected at their ends to the screen body 113 with suitable shear mounts 151, 152 respectively.

Each bearing housing arm of the screen adjacent the feed end, for example arm 139, is further provided with an upstanding plate 159 which extends upwardly from the arm 139 to above the upper deck 114 and side plate 119. A like plate 160 is for hearing housing extension 139a at the comparable position on the other side of the screen body 113. Plates 159, 160 are connected by a horizontal plate 161 which is suitably secured across the, upper edges of the plates. Thus, plates 159, 161i and 161 provide a positive linkage between the outer bearing housing extensions 139, 13921. Plate 161 is further provided with a table 1 17 upon which a suitable motor 146 can be mounted for a driving connection with a pulley 142 secured to gyrating shaft 130 through a suitable linkage, such as V-belts 143, which extend between pulley 142 and a sheave 144 secured to the motor drive shaft 145. As a variant, table 147 can be omitted and motor 146 mounted directly to plate 161.

Intermediate the plates and the end of their adjacent arm, for example, between plate 159 and the end of arm 139, a suitable hanger bracket 165 is provided to at-:

tach screen body 113 by a vertical hanger 166, which may be formed of rodding, cable and the like, to suspend screen body 113 from an overhead supporting structure 111. Interposed between the upper end of hanger 166 and supporting structure 111 is supporting mount 153 which, as shown, comprises a compression spring 167 operatively interposed between a top plate 168 and a bottom plate 169 which are secured by nuts 170. A like bracket 171, hanger 172, spring 173, plates 174, and nuts 176 make up a supporting amount 154 intermediate bearing housing 137 and stabilizing mount 152. Like parts appear on the other side of the device and those that appear in FIGS. 5 and 6 are designated with a suffix a. The relative lengths of hangers 166, 166a, 172 will, of course, be selected to provide the desired inclination to body 113 While the selective tightening of nuts 170, 176 provides an easy method for leveling out the screen decks.

In operation, both embodiments are predicated upon essentially an identical concept, namely, the screen body is connected directly to each outer bearing arm by resilient stabilizing mounts while the outer bearing arms are directly connected to a stationary support structure by resilient supporting mounts. Thus, the outer hearing arms of the screen remain stationary during the normal balanced operation of the screen because the force of gyrations of the screen imparted to stabilizing mounts are simultaneously counteracted by an equal and opposite force imparted by the shaft to the outer bearing arms. When, however, severe overloading of the screen occurs, as when clumps of material strike the upper deck or material sticks thereto, an unbalance occurs because a loss of motion occurs rendering the reactive force of the bearing arms greater than the forces of gyration in the stabilizing mounts. But this unbalanced force must pass through the supporting mounts where they are substantially completely absorbed before they reach the supporting structure. As a result, the screen is substantially completely self-compensating and cannot be unbalanced to the state where severe vibrations will be transmitted to 7 the building in which the screen is mounted. Thus, the severe wear on both supports and building normally attendant the severe vibration of the prior screens is for all practical purposes substantially completely eliminated.

Thus, whereas the screens of prior art, such as the aforementioned 'Parks screen, become unbalanced in operation (as when material adheres to the screen surfaces or shock loading occurs) and transmits an objectionable amount of vibrations to the buildings, the screens embodying the present invention completely obviate this disadvantage and fulfill to a remarkably unexpected extent the objects hereinbefore set forth.

Furthermore, the Parks screen because of the continual movement of its outer bearing during running stabilizes its body to the building so that all shocks received therein must be transmitted through all of the screen bearings and to the building, whereas the screen of the present invention obviates these disadvantages in the manner which was previously explained.

While only two structures embodying the present invention have been herein described and illustrated, it is, of course, understood that such modifications, alterations and applications as will readily occur to those confronted with this teaching are intended within the spirit of this invention, especially as it is defined by the appended claims.

Having now particularly described and ascertained the nature of my said invention and the manner in which it is to be performed, I declare that what I claim is:

l. A screening device comprising: stationary support means; a vibratory body having substantially parallel side Walls; a first set of bearings carried by said side walls, one in each one of said walls and in substantial registry with each other; a second set of bearings, one being adjacent each of said side Walls in spaced relationship thereto in substantial registry with each other and out of registry with said first set of bearings; a substantially horizontal continuous gyrating shaft engaging said first and said second set of bearings and extending through said body to impart gyratory movement thereto; a bearing housing disposed about each of said second set of bearings and having a first and second outreaching rigid arm portion connected directly to said housing and extending from opposed portions of said housing; a plurality of resilient shear mounts connected one between each of said rigid arm portions adjacent the end thereof and said body to stabilize said body; and a plurality of resilent compression mounts connected one'between each of said rigid arm portions and said support means intermediate said stabilizing mount and said one of said second set of bearings and said compression support mount being substantially closer to said stabilizing mount than to said bearing.

2. In a screening device having a screen body in which a vibrating mechanism is mounted with projecting shaft portions journaled in outer bearing housing assemblies at opposite sides of the screen body, a pair of rigid extension arms connected directly and rigidly to each outer bearing housing to extend rigidly and oppositely from each other, a resilient stabilizing mount connecting each rigid extension arm to said screen body, and a resilient supporting mount connecting each rigid arm to a sup port member, with the stabilizing mount and the supporting mount being separate assemblies spaced apart from each other along an axis parallel to said arms.

3. In a screening device having a screen body in which a vibrating mechanism is mounted with projecting shaft portions journaled in outer bearing housing assemblies at opposite sides of the screen body, a pair of rigid extension arms connected directly and rigidly to each outer bearing housing to extend oppositely from each other, a resilient supporting mount connecting each rigid extension arm to a support member, each rigid arm having a terminal portion projecting rigidly beyond the supporting mount in the direction away from the outer bearing housing, and a resilient stabilizing mount separate and spaced from each supporting mount along an axis parallel to said arms, the stabilizing mount connecting the terminal portion of said arm to the screen body.

References Cited in the file of this patent UNITED STATES PATENTS 2,066,362 Parks Jan. 5, 1937 2,176,376 Denovan Oct. 17, 1939 2,313,765 Parks Mar. 16, 1943 2,925,911 Parks Feb. 23, 1960

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