US2153243A - Vibratory screen - Google Patents

Description

April 4, 1939. J. A. FLINT VIBRATORY SCREEN Filed Dec. 12, 1934 2 Sheets-Sheet 1 VENTOR James Af /#17:.

April 4, 1939. A. FLINT 2,153,243

VIBRATORY SCREEN Filed Dec. 12, 1954 2 Sheets-Sheet 2 umes A. F7077 G na/4 ATT'Y' messed Apr. 4, 1939 VIBRATORY SCREEN James A. Flint, Bexley, Ohio, assignmto The Traylor Vibrator Company, acorporation of Colorado Application December 12. 1934, Serial m3. 151,100

9 Claims.

This invention relates" to a screening device of the vibratory type and particularly to such a device in which the vibratory motor is arranged to impart a conveying action to the screen, independently of gravity.

An "object of the invention is to provide a screen of the above mentioned type with a pivoted motor whereby the conveying and screening action of said motor may be adjusted.

Another object of the invention is to provide a pivotal connection between a screen and a motor which vibrates said screen.

Still another object of the invention is to provide a vibratory screen and conveyor to which is pivotally connected a motor for vibrating said conveyor, the axis of vibration of said motor making an adjustable angle with the material supporting surfaces of said screen and conveyor.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the drawings:

Fig. l is a side elevational view of a device embodying my invention;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1 looking in the direction of the arrows; and

Fig. 3 is a sectional view taken on the line of Fig. 1 looking in the direction of the arrows.

Referring particularly to the drawings, there is seen a device comprising my invention having a deck assembly it with a screen it and amate-= rial receiving hopper l2.

Adjustably and pivotally attached to said deck assembly It is a motor it which, when energized as by alternating current, is operative to impart a vibratory motion to said deck assembly. By virtue of the acute angular relation between the axis of vibration of said motor l3 and the screen ll, said motor is effective to vibrate any materials on said. screen to efiect a screening thereof and is also effective to impart a conveyor action thereto independent of any conveyor action due to gravity, caused by tilting of the screen. Therefore, when material is fed to the screen i I through the hopper l2, it will move downwardly across said screen I l while the particles thereof are subjected to a screen-operation, the downward movement being caused by both the inclination of said screen H to the horizontal and the conveying action of said motor l3 with respect to saidscreen. If desired, the screen ll may be placed horizontal, in which case the conveying action will be due entirely to the motor l3. Also, the

angle of inclination made by the axis of the m0- tor l3 to the screen I I may be varied by the pivotal adjusting means It whereby the relative amounts of conveying and non-conveying components of the movement of the material particles, caused by motor l3, may be variably determined.

The material fed to the screening device is, of course, separated according to the mesh of screen i l, and the fractions thereof which will pass said screen pass therethrough and are carried by the trough bottom l6 of said device to be discharged at the lower end thereof. Those fractions of the material which are too large to pass the screen are discharged at the lower end of the screen. Separate receptacles or conveyors may be fed by the screen and the bottom of the device respectively to receive separately the screened and unscreened fractions of said materials.

Considering more particularly the detailed construction of the device, it is seen that-the deck assembly it] comprises a trough formed by side walls 95 and a bottom wall it. Extending laterally between the side walls l5 and longitudinally spaced alongthe deck to are the reinforcing and screen supporting cross ribs ill, the ends of which are rigidly attached to said side walls 55, as by welding. linciined flanges 58 extend along the walls iii and adjacent the tops of the ribs i'l, being rigidly attached at their. top portions to said side walls it? and adjacent their bottoms to the ribs ll. Gushioning means for the screen it, in the form of U-shaped rubber channel caps is, fit over the tops of the ribs i'l. Extending longitudinally of the trough is a pair of spaced reinforcing ribs (it which are rigidly attached to the bottom it at their bottoms, as by welding, and are siotted at their tops to receive the cross ribs ill, .to which they are rigidly attached as by welding. The tops of the cross ribs ii are not in a plane but form an arch whereby when screen ii is stretched thereover it will have firm contact with each cap id, thus iii preventing any relative movement of said screen with respect to said caps l9 during vibration of said screen. i v

It is thus seen that the cross ribs H, the longitudinal ribs 20, the rubber caps iii and-the flanges l8. present a framework across which is adapted to be stretched a screen I l, which screen when so stretched is held rigidly in place and is protected from excessive wear, by the general arched configuration thereof and by the rubber insulation between the cross ribs l1 and said screen. If desired, rubber strips may also be laid between the flanges l8 and the edges of said screen II. Such strips are usually employed with a very iine mesh screen but are not generally employed with a heavy screen.

To reinforce the deck, there may be provided laterally extending webs 2| across the lower surface of bottom It thereof and across the rear face of the hopper I2, which webs 2i may be provided I with longitudinal angle reinforcing webs 22. Additional reinforcing webs 23 may be provided adjacent the side walls I5 at the outside and near the discharge end thereof. All of said webs are rigidly attached to the deck, as by welding.

The end fastening and tensioning means for the screen II comprises a fixed cylindrical pipe 24 adjacent the discharge end of the deck which has its ends welded to the side plates I 5. A series of pins 25 are rigidly attached to said cylinder along the length thereof and have hooked ends which project outwardly to receive apertures in a removable angle clamp 26 adapted to be attached to one end of the screen H. The detailed construction of this fastening means is disclosed and claimed as a part of screen tensioning means in my co-pending application for a Vibratory screening device, Serial No. 757,159, filed December 12, 1934.

The opposite end of the screen II is attached to an adjustable tensioning cylinder 27 which is held between arcuate bearings 28 formed in side walls I5 and adapted for rotation therein. Each and of said cylinder 21 is provided with a lever arm 29 having a bifurcated end which is notched at 30 to receive a trunnion nut ll through which is threaded a tensloning bolt I2 having a spring pressed bearing block 3! riding in a V-shaped bracket 34 rigidly attached to a side wall II. It is obvious that the tensioning of the screen II across the above mentioned framework of deck III may be effected by adjusting the bolts 32 on each side of said deck which will wrap the screen around the cylinder 21. Said screen II is attached to the cylinder 21 by removable angle attaching means 35 cooperating with pins 36 similar to the attaching means at the other end thereof. If desired, additional retaining brackets having lugs extending into holes through lever arms 28 adjacent the central axis of cylinder 21 and attached to the side walls Il may be employed. These brackets are shown in detail in my above mentioned application, in which this screen tensionlng apparatus is claimed.

The deck may also include a hood or cover 81 which is preferably removably attached to side flanges 38 adjacent the tops of the side walls ID. If desired, this hood or cover may be rigidly and non-removably attached to said side walls, as by welding. Said hood is preferably supplied with reinforcing angle ribs 39, welded thereto, and may be provided with a central bracket 4. having an aperture adapted to receive a flexible suspending means. This hood or cover 31 is preferred where the material being treated may contain dust or may be poisonous and when employed a canvas or duck chute is usually attached to the discharge ends of the device to form a flexible conduit to a receiving bin or receptacle.

Rigidly attached to each of the side walls I! of the deck III is the pivotal adjusting means I 4 for adjustably and pivotally attaching the motor I3 to said deck, whereby the angle made by the axis of vibration of said motor with respect to the screen II and bottom wall ll of said deck may be adjustably determined. This means comprises an arcuate plate 4I rigidly attached to each of the side walls I4, as by welding. Each of said plates has an opening adapted to receive a pivot bolt 42 provided with a nut, which bolt extends through said plate and side wall I5 of the deck and through a selected one of a plurality of openings 43 in a pair of connecting channel members 44. Each of said plates 4| is also provided with a series of arcuately disposed apertures 45 adapted to receive selectively a pair of bolts 48 which extend through one pair of a plurality of selected openings 41 in each of said channel members 44. A flange 48 may be provided adjacent one edge of each plate H to reinforce said plate and to limit the amount of pivotal movement of the channel members 44. While in the device illustrated the arcuate plates 4| provide only for adjustment oi'the motor I3 with respect to the deck I0 so that the conveying action of the motor II, per se, will always be in the same direction--that is, to the right, as viewed in Fig. 1-it is to be distinctly understood that said plates 4I may be extended so that said channel members 44 are substantially at right angles to the screen II and bottom I6 of said deck III, or may even form an acuate angle therewith opposite to that as illustrated in Fig. 1; that is, by pivoting the said channel members to the left of a line perpendicular with said screen II or bottom- I6. Such a construction has actually been made by applicant. In addition, the flange 48 may be eliminated, if desired.

Instead of positioning the plates 4| so that the motor I 3 projects above the deck I 0, they may be positioned substantially 180 degrees from the position illustrated in Fig. 1, in which case the motor I3 would project downwardly from the deck Ill. The arrangement of the motor I3, either above or below the deck III, is an optional matter to be determined primarily by the space and the mounting available.

The longitudinal adjustment of the channel members 44 provided by the longitudinally spaced apertures 43 and 41, of course, provides for an adjustment of the motor I3 relative to said deck, which provides for mounting the device in different sized spaces and to accommodate diiferent supporting structures available.

The angular variation provided by the adjustable pivotal connection of the motor I3 to the deck IIl through channel members 44, provides for a variable division of the energy generated by motor II for the two distinct functions performed by said motor. If the channel members 44, and thus the axis of vibration of motor ll, are disposed at right angles to the screen I I and bottom l6 of the deck III, then substantially all of the force of each vibration is eifective for screening purposes. That is, this force is eifective to vibrate the screen I I and bottom I6 of said deck substantially vertically of itself. The motor, per se, thus has no conveying action. However, when the channel members 44, and thus the axis of vibration of motor I3, make an acute angle with the screen II and bottom I6, this force of each vibration of the motor has a component which is perpendicular to the screen II and bottom I8, and

'a component which is parallel therewith. If the vertical component of force is made relatively large, as compared to the horizontal component, as by making a large acute angle between the axis'of the motor and the screen II and bottom I6, then there will be considerable screening action on said screen I I and little conveying action on said screen and on the bottom I 6, due to the motor II. That is, considering only the effect of the motor, material would pass slowly along the screen II and bottom 16 and would be subjected to vigorous screening action. On the other hand, if the vertical component of force 13 made relatively small, as compared to the horizontal component, as by making said acute angle small, then there will be less screening action on said screen H and considerable conveying action on said screen and on the bottom 18, due to the motor l3. It is thus evident that by pivotally adjusting the adjusting means I, a wide range. of screening and conveying actions may be obtained,

. depending upon the material being treated, the

difficulty of screening thereof, the tonnage per hour desired and the efficiency of separation required, thus taking care of a large number of variable conditions encountered in practice. The proportionate conveying and screening actions above mentioned are due entirely to the action of the motor l3 and are therefore independent of the inclined position of the deck assembly l0. That is, said deck assembly l may be horizontal,

inclined as illustrated in Fig. 1, or inclined in a re erse direction to that illustrated in Fig. 1.

In addition, the angle of tilt of the deck as-' sembly H) to the horizontal may be independently adjusted thereby to vary, as desired, the conveying action due to gravity. This is set forth more in detail hereinafter. This additional adjustment allows for a condition where both vigorous screening and rapid conveying is desired, for the conveying action may be largely obtained due to gravitational action.

The construction of the vibratory motor I3 is substantially in accordance with the disclosu're of my above mentioned application except for such changes as are necessary to adapt it to the present device. Said motor comprises an armature assembly 50Qand a field assembly The armature assembly and field assembly are flexibly attached together through the intermediary of the stacked leaf springs 52. Thus, when the motor is energized by alternating current, there will be vibratory movement between the armature assembly 50 and the field assembly 5! and the frequency of this vibration will be twice the frequency of the energizing source, as the armature will be attracted by the field during each half cycle of alternation. Where a fill-cycle source is employed, the frequency of vibration will, therefore, be 120 cycles per second. The motor may be designed for any desired commercial frequency, such as 60, 50 or 25 cycles per second.

The vibrations of the motor 13 are imparted to the deck by virtue of the fact that the armature assembly 55 is rigidly attached thereto through the'channel members 4t and the field assembly 5i is made as areaction body principally due to the weight thereof, the major portion of which is represented by the heavy'cast-= ing 53.

To employ the major portion of the energy generated by the motor l3 to do useful work by vibrating the deck l0 ,rather than useless work by vibrating the field assembly St, the weight of said field assembly is preferably made appreciably larger than the weight of the vibratory assembly represented by the combined weight of said deck l0 and the armature assembly 50 which is rigid therewith. As the relative amplitudes of vibration of the said vibratory assembly on the one hand and the field assembly on the other are inversely proportional to their weights, the field assembly 5| should be as heavy as practical and preferably at least twice as heavy as said deck vibratory assembly l5.

While not absolutely essential to the operation of the device, the efllciency of operation thereof is greatly enhanced and the energy consumed is greatly decreased, if the vibratory assembly comprising the deck ll and the armature assembly 5|, including all parts rigid with either, are designed with respect to the spring leaves 52 so that they present a vibratory unit which has a natural period of vibration approximately equal to the period at which said motor is vibrated. Exact resonance is not necessary or preferred but it is preferred to have the natural period of said body slightly higher than the period of vibration of said motor, whereby the motor will always be loaded and whereby upon loosening one of the clampings of the leaf springs 52 the natural period of said vibratory assembly may be reduced to approach resonance more nearly where a greater amplitude of vibration is desired than is otherwise obtainable.

Referring more to the details of construction of the motor l3, and considering first the armature assembly 50, there is seen at the armature comprising stacked laminations which may be cla'mpedbetween side plates 55 by bolts extend.-

ing through said side plates and laminations.

Said side plates 55 have bo tom brackets which are bolted to the base 56 of an armature shaft 5'! having an extended head 58, provided with reinforcing ribs and adapted to be attached at its opposite ends 59 to the upper ends of the channel members 44, as by nuts and bolts 60. Said shaft 5"! is provided with a transverse opening Bl. through which extend the leaf springs 52. Said leaf springs are rigidly clamped to said shaft 51 by the clamp studs 52 which thread through the base thereof and bear on a clamping plate 6|, thereby clamping said springs against the boss 52' extending inwardly of said opening 6|.

The field assembly 5!, comprises a U-shaped magnetic path built of stacked laminations 63 clamped to a split bracket 64 by bolts extending therethrough, the legs of which laminations are surrounded by a pair of energizing field coils 65 which are appropriately clamped between the split bracket 64 and a clamping plate 66, as by elongated bolts surrounded by spacers 61. The above described portion of the field assembly is adjustably but rigidly attached to a pair of U-shaped frames 68 by adjusting bolts 69' which extend through threaded apertures in the split base of said frames 68. Clamping bolts 69 with appropriate nuts are provided to clamp the adjusting bolts 55' in any position of adjustment. The said bolts 69' removably secure the frames 38 and the split bracket 84 by nuts either one or both of which may be threaded on said bolts. The upper ones of said nuts Ill are preferably formed integral with the bolts 69'. The frames 58 are attached at their feet ll to the heavy casting 53, as by machine screws I2.

The heavy casting 53 is provided with a longi tudinal opening 13 through which the leaf springs 52 extend. Said opening has an inwardly extending boss It at each lower end and inwardly projecting clamping studs I5 at each upper end which bear on clamping plates 16 to clamp the ends of said leaf springs rigid with the casting 53.

It is preferred to place a small spacer 52' between each leaf spring adjacent the end and center clamping areas whereby the individual leaves will be slightly spaced. Said spacers may cussion of the deck III,

well take the form of a thin strip of composition board or any other suitable material.

The device may be suspended by three point suspension means, two'of which means are attached to eyes 18 at the opposite ends of casting l8 and one of which is attached to bracket II. If desired, four point suspension may be employed by employing two brackets, instead of bracket I, which two brackets would be attached to the side walls ll of the deck Ill. The suspending means preferably includes a flexible link to prevent any sub stantial transfer of vibrations to the superstructure and comprises a hanger 11 having a lower hooked end it adapted to cooperate with eye It or apertured bracket 40. The hanger ll extends into cylinder 19 containing a coil spring OI coiled about said shaft. One end of said coil spring 80 abuts a nut and washer II on hanger l1 and the other end abuts cylinder head 82. A suspension rod 83 has a head which is attached to the cylinder head 84 thereby supporting said cylinder. Each of these rods, which cooperate with motor I3, is preferably threaded to receive a turnbuckle 85 to provide for adjustment of the inclination of the deck assembly l0. Similar turnbuckles may or may not be provided with the rods cooperating with the deck assembly it.

It is, of course, evident that any pivotal movement of motor I! about the axis of bolt 42 will tend to change the inclination of the screen II and trough bottom It. To provide for adjusting this inclination either as an incident to a pivotal change of motor I! about the axis of said bolt 42 or independent thereof is the function of the turnbuckles 85. In addition, hanger rods of different lengths may be provided if a wide range of adjustment is desired. If a wide pivotal adjustment of the motor I! is to be provided for, it may be necessary to move the top pivot point of the hanger rods 83 whereby they will hang substantially vertically. For this purpose a plurality of spaced hanger eyes may be provided for each of the hanger rods 88 which eyes will be carried by the supporting structure. Where the device is designed to have the motor ll project below the deck assembly ill, the will preferably be positioned nearer the discharge end of the deck assembly III, or the entire device may be supported by brackets attached forwardly and rearwardly of the deck section II alone, no haanger then being directly attached to the motor To operate the' device, it is first suspended in a desired manner; for example, as illustrated in Fig. 1 of the drawings. In this particular position, the deck I0 is sloping so any material on screen Ii or trough bottom ll will tend to move to the discharge end under the influence of gravity. In addition, the action of the motor II, when vibrating, will impart vibratory motion to said deck along'the axis of said motor which is along the longitudinal center thereof and along the longitudinal center of the channel members 44, Itshould be pointed out that this axis of vibration preferably passes through the center of perto prevent any tendency of said deck to rotate under the influence of said motor and to utilize most efiiciently the energy of said motor. Due to the angular inclination of the axis of said motor I! to said screen II and trough bottom it, each of said latter elements will have a conveying action due to the motor. The screen It will also have a screening action.

Material being fed at hopper II will there- ,of passing said screen bracket ll fore travel downwardly across screen I I under the combined influence of gravity and the conveying action of motor II. This material will be separated by screen II, the fractions thereof capable passing therethrough to the bottom wall It and being thereby conveyed to the discharge end of the trough of said deck where they may discharge into a hopper or receptacle or onto a conveyor. Those fractions of the material incapable of passing the screen Ii will, of course, be discharged from the discharge and of said screen into a separate hopper, reoeptacle or conveyor.

It is evident that by changing the inclination of the deck II the conveying action due to gravity may be controlled independently of the motor II. By pivotally adjusting the motor II, the relative amounts of energy thereof employed for conveying and screening may be adjusted.

While in the arrangement illustrated in Fig. 1, the conveying action of gravity and of the motor It are cumulative, they may be made differential. For example, it may be necessary for a particular installation to incline the deck at a steep angle which would provide too rapid a rate of movement of material thereacross for the adjustment illustrated. The rate of movement may be reduced by reducing the conveying action of the motor I: in the manner above described or, if necessary, by making the conveying action thereof opposed to the movement of the material under the influence of gravity. For example, by pivoting the motor. about bolts 42 to a position where the axis of vibration thereof makes an acute angle with the feed endoi said conveyor, the conveyor action of motor II will oppose the gravitational conveyor action on said material.

If it is desired to employ substantially all of the energy of motor It for screening action,'the axis of vibration thereof-may be placed at right angles to the deck II in which'case gravity alone would operate to move the material across the screen Ii and trough bottom it.

Theadjustable bolts I are effective to adlust the air gap of the motor ii. In the absence of such an adjustment, this air gap would vary widely depending upon the number of spring leaves 82 which were employed and would vary somewhat dependingupon machining accuracy of the parts. The number .of spring leaves 52 is determined by the weight ofthe vibratory mass rigid with the deck assembly I. and in certain cases there may be considerably fewer spring leaves employed than the maximum number which could possibly becarried by opening 6! of armature $1 and opening 13 of casting 53. The air gap 'of motor I! is preferablymaintained of constant length, though it is possible to vary the length thereof; thereby to vary the amplitude of .ibration of the device. It is evident that the smaller the air gap the greater will be the attraction between the armature 54 and the poles of the field assembly ll.

A variable resistance is preferably inserted in series or in shunt with the field windings 65 to control the strength of the electro-magnet and consequently the amplitude of vibration of the device.

The device of my invention has been found to be extremely flexible due to the many adjustments possible and may therefore be employed for widely divergent purposes and under conditions.

Obviously those skilled in the art may make various changes in the details and arrangement widely varying 30 Y motion having a conveying component perpenof parts without departing from the spirit an'd scope oi the invention as defined by the claims hereto appended, and I- wish therefore not to be restricted to the precise construction herein dis Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

' 1. In a conveyor, the combination with a deck having a material supporting surface, of a motor for imparting vibratory motion to said deck, means connecting said motor to said deck at a variable anglewith respect to said surface, which may be varied from an acute angle to an obtuse angle, said means comprising a pair ofspaced arms rigidly connected to said motor and pivot-- ally connected to said deck and means teflx saidarms in a selected position withrespect to said deck 2. In a screening device, the combination with dicular to said support and a conveying componentparallel with said support, said vibrating means being adjustable to change the direction or said conveying component parallel with said support by 180 degrees, and to reduce it to substantially zero. v

4. In a vibratory screening device, the combi-r nation with a screen, or means for supporting said screen on a slope, means for vibrating said screen with a rectilinear motion having acomponent at-ri'sht. angles to said screenand with a component parallel with said screen, said means being so constructed and arranged that it may be adjusted so said parallel component or oppose movement oimaterial over said orwill be reduced substantially to more in which} latter case substantially the entire movement will be represented by saidright anglecomponent,

5. In a conveyor, the combination with a deck, or a material support-carried byvsaid deck, vibratory electro-magnetic motor means having a rectilinear vibratory movement tor vibrating said deck, and'adjustable means for connecting said motor means to said-deck at such variable angles thattheuisofvibrationthereoimaybeadjmted iromanacuteangletonnobtussanglowithro essence spectto the relative to one thereof."

,- "8. 'In a conveyor, the combination with a deck,

of smash support carried by said deck, means (or supporting said deck with the material sup-v port sloping downwardly from its teed end, vi-

bratory electro-magnetic motor means having a rectilinear vibratory movement for vibrating said deck, and adjustable means attachin said motor to said deck for adjustment oi the axis of vibration thereoi from an acute angle to an'obtuse angle as viewed from one end of said deck relative to the plane 01 said material support.

7. In a conveyor, the combination with a deck. of a screen carried by said deck, means tor supporting said deck with the screen sloping downwardly from its teed end, vibratory electro-magnetic motor means having a rectilinear vibratory movement for vibrating said deck, and adjustable means attaching said motor to said deck for adjustment of the axis of vibration thereof from an acute angle to an obtuse angle as viewed from one end of said deck relative to the plane of said screen.

8. In a conveyor, the combination with, a deck having a screen thereon, of a vibratory electromagnetic motor for imparting vibration to said entire deck along a straight line axis, and means for connecting said motor to said deck at a variable angle with respect to said screen whereby the relative values of perpendicular and parallel components 0! vibratory movement relative to said deck may be variedthereby to adjust readily the relativevalues of screening and conveying components, comprising a pair of spaced arms extending from the armature of said motor and pivotally attached to opposite sides of said deck and at least in part supporting said deck. a pair of plates carried by said deck and having spaced holes therein, and fastening means adapted to extend through selected ones 0!. said apertures and through aligned holes in said arms.

9. In a vibratory screening device, the combination with a deck, or a screen supported by said deck, means for vibrating said screen along a rectilinear axis with avmotion having an essentially screening component perpendicular to said screen and an essentially conveying t parallel with said screen, and means providing for swingingsaid vibratory to swing the axis of vibration thereoi relative to said screen and thereby vary the ratio of said two components oi motion to varythe relative mm of conveying and screening action

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