US2707559A - Adjustable vibrating screen - Google Patents

Description

May 3, 1955 w. E. SAXE ADJUSTABLE VIBRATING SCREEN 2 Shets-Sheet 1 Filed June so, 1952 WALTER B SAXE,

IN V EN TOR.

R! Em E N a g mu M b ER WW m 0 y 3, 1955 w. E. SAXE ADJUSTABLE VIBRATING SCREEN 2 Sheets-Sheet 2 Filed June 30, 1952 WALTSP E. SAXE',

INVENTOR.

HUEBNER, BEEHLER,

W m AU V, B

United States ADJUSTABLE VIBRATING SCREEN Walter E. Saxe, Pasadena, Calif., assignor to The Conveyor Company, Vernon, Calif., a corporation of California Application June 30, 1952, Serial No. 296,374

11 Claims. (Cl. 209-325) The invention relates to screening devices and has particular reference to a screening device of a type which is particularly effective in screening aggregate in the nature of sand and gravel. The screening device herein made the subject matter of this patent is, however, one

adapted to a number of adjustments sufficient that by which is vibrated or agitated is inherently subjected to considerable wear and tear. Because of the constant motion, parts break down or, if constructed sufiiciently heavily to resist wear for a long period, they then become heavy and cumbersome to the extent that elliciency is impaired or else result in a construction which is overriced for the use to which it may be put.

It has also been found that the frequency of vibration and also the character of the vibratory motion has a considerable effect upon the effectiveness of the screening. Vibrating and agitating screens heretofore devised have for the most part been built with the point of application of the vibration at a fixed location. Thus constructed the screens, while suited more especially to one purpose, become entirely unsuitable and in fact inoperable when it is attempted to devote them to some other purpose. They are usually ineffective under unbalanced loading.

it is therefore among the objects of the invention to provide a new and improved vibrating screen which is simple in its construction and mounted in such fashion that although relatively light in weight it can be operated for long periods of time without undue or excessive wear of the parts.

Another object of the invention is to provide a new and improved vibrating screen so constructed that the vibrating characteristics can be changed and altered at will in order to adjust the screen so as to accommodate any one of a number of different kinds of mixed aggregate and accommodate the vibration forces to the average loading at various locations on the deck.

Another object of the invention is to provide, a new and improved vibratingscreen which is adjustable to the extent that one portion of the screen may be subjected to vibration of one characteristic while at the same time another portion of the screen may be adjusted to vibrations of a different character, both of which, when most advantageous, can be applied in a direction at 90 to the plane of the screen.

'Still another object of the invention is to provide a freely floating vibrating screen which is resiliently mounted in such fashion that the weight of the screen even while vibrating is sufficient to maintain a suitable atent tension on a belt drive without the employment of accessory tightening devices which might become worn and rendered ineffective by the constant vibration of the screen.

It is further among the objects of the invention to provide a new and improved vibrating screen adapted to the employment of screens of any selected mesh or screens having more than one mesh characteristic and which by the employment of suitable off-center weights on rotating driven shafts can be adjusted by shifting the location of the weights in order to vary the motion of the screen under vibration to a considerable degree, thereby to readily adapt the device to an aggregate of virtually any selected character and further to make possible the use of a greater variety of mesh combinations than has heretofore been possible.

With these and other objects in view, the invention consists in the construction, arrangement and combination of the various parts of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a side elevational view of the device suspended from a suitable support.

Figure 2 is a plan view of the screening portion of the device taken on the line 2-2 of Figure 1 and show ing one of the adjustable vibrating weights partially broken away.

Figure 3 is a cross-sectional view taken on the line 3-3 of Figure 2.

Figure 4 is a fragmentary cross-sectional view taken on the line 4-4 of Figure 1.

Figure 5 is a longitudinal sectional view of the resillent supports employed in suspending the screen, which supports are shown in elevational view in the upper porlion of Figure 1.

In an embodiment of a form of the invention chosen for the purpose of illustration there is shown a frame or support from which a vibrating screen device 11 may be suspended by employment of short cables 12 at an upper or charging end and cables 13 at a lower or discharge end. Power for vibrating the screen originates in a source of power (not shown) which is conveyed by means of a belt 14 to suitable rotating parts, the initial application of which is at the upper end of the frame.

The vibrating screen device comprises a free swinging frame 15 having longitudinal side elements 16 and 17, an upper transverse element 18, and a lower transverse element 19. A beam 20 extending transversely across the mid-portion may be employed to give additional strength and stability and to assist angle irons 21 and 22 in providing a transverse bracing. A screen 25 is shown stretched over the frame. For suitably connecting the screen to the frame in a taut position the screen itself is provided with longitudinal stiffeners 26 and 27 extending throughout the length of the screen.

On one side of the frame adjacent the element 17 is an inwardly turned angle 28 on the upper flange of which is welded an anchoring angle 29 somewhat smaller in cross-section and located in such fashion that a leg 30 of the angle 29 is spaced from a leg 31 of the angle 28 inorder to permit the screen to be located therebetween.

On the opposite side of the frame adjacent the element 16 is an inwardly turned angle 35 upon which is mounted a series of longitudinally spaced hooks 36 which extends through a flange 37 of the angle 35.

The stitfeners 26 and 27 anchored to the longitudinal edges of the screen are turned upwardly as illustrated in Figure 3 to provide reversely directed outer edges 38 and 39 to assist in anchoring the screen on the frame. As best' shown in Figure 3 the edge 39 engages behind the leg of the angle 29 and the edge '58 is engaged at spaced intervals by the hooks 36 which can be tightened by means of nuts 40 in order to draw the screen 28 tightly across the mid-portion of the flange. It is suggested further that the screen 25 at its upper end 41 may be of finer mesh than the screen at its lower end 42 where a varied mesh may be suited to some individual purpose.

For giving the screen its vibration characteristics there are provided driven shafts 45 and 46 on respectively opposite longitudinal sides of the frame, these shafts being mounted each in a bearing 47 at the lower end and a comparable bearing 48 at the upper end. It is also advantageous to provide a bearing 49 at the mid-portion as illustrated. A coupling 50 may be employed to facilitate mounting of the driven shaft in position. An extension 51 on each of the driven shafts extends through the bearing 48 in each case to a location within a housing 52, in which location it has mounted thereon a bevel gear 53 adapted to mesh with a bevel gear 54.

A transversely disposed drive shaft 55 is shown mounted at the upper end of the frame in suitable bearings. One such bearing is illustrated by the reference character 56 and is positioned immediately adjacent a multiple drive pulley 57 to which the belt drive 14 is connected. The drive shaft 55 is further rotatably supported by suitable bearings within extensions 58 on the element 16 and 5.9 on the element 17. Stiffening members 60 and 61 may be secured adjacent the extensions in order to provide suflicient rigidity and also to provide a support for the housings 52 and the respective end of the drive shaft 55. it will be noted that the bevel gears 54 being located at the outside ends of the drive shaft 55 are adapted to provide a rotating connection between the drive shaft and the driven shafts 45 and 46 so that t shafts, and that the weights may be the same or different depending upon the special characteristics which are to be given to the vibrating screen device. The weights are similar in form and mounting to the end that a description of the weight 66 will sufl'ice for a description of all.

As shown the weight 66 has an aperture 68 extending therethrough in order to slidably engage over the lower end of the driven shaft 46. To anchor the weight upon the shaft there is provided a set screw 69 in the large side of the weight adapted to bear against a shoe key 70 mounted in an appropriate slot 71 of the driven shaft 46. The slot 71 extends substantially throughout the entire length of the driven shaft. It will be understood from this that the eccentric weight 66 may be slid to any one of a number of positions throughout the length of the lower end of the shaft between the bearing 47 and the bearing 49 and there tighened in place. The opposite eccentric weight 64 may be similarly positioned, either directly opposite the weight 66 or above or below it, should such an adjustment be desirable. It will be noted, however, that the large sides of the eccentric weights 64 and 66 are positioned so that they both are directed inwardly at the same time and outwardly at the same time as well as simultaneously upwardly and downwardly. Thus positioned, the weights compensate each other in a lateral direction and work together in an upwardly and downwardly direction to the end that the screen is vibrated up and down but not laterally.

Weights 65' and 67 may be similarly adjusted so as to operate in a similar fashion at the upper ends of the re may be adjusted entirely independently of the weights at the lower ends so that the upper end of the screen may be given one vibration characteristic entirely different from the vibration characteristic of the lower end of the screen. Since the upper end of the screen usually carries a heavier load tending to dampen vibration, it may be advantageous to substitute weights of greater mass or eccentricity at the upper end. For that purpose the driven shafts 45 and 46 may be readily removed to facilitate the change and replaced.

The cables 12 and 13 previously identified mount the frame and the screen so that the screen can be vibrated freely and unrestrictedly by operation of the rotating eccentric weights. To provide the necessary resilience in th mounting there are provided spring housings 72, one for each cable. Details of the housings are illustrated in Figure 5. As there indicated the housing is a hollow inverted cylinder welded to a flange 73 of an I beam '74. The housing has a closed bottom 75 and within the housing is located a coiled compression spring 76.

A suspending link 77 extends upwardly through a suitable hole 78 in the flange 73 and at the upper end of the link is a washer 7 which engages the upper end of the spring 76.

At the bottom end of the link is an eye 80 adapted to receive a coupling 81 at the upper end of each of the cables.

An eyelet 32 is provided at each of the four corners of the frame into which is engaged in each case a coupling 83 for the attachment of the respective cable.

Suspended as described the frame and screen are permitted to move up and down freely in response to the vibration eft'ect produced by rotation of the eccentric weights. Moreover, because of. the free suspension the frame may be biased slightly toward the right, as viewed in Figures 1 and 2, at which point the belt drive 14 may be secured to the pulley 57 and a suitable pulley on the source of power, not shown. Mounted in this fashion the weight of the frame and elements mounted thereon tend to pull slightly from right to left as viewed in Figures 1 and 2, thereby to maintain a suitable driving tension on the belt drive.

In operation the aggregate to be screened is shovelled or chuted upon the upper end or charging end of the screen, preferably while the vibrating mechanism is being operated by power supplied through the belt drive communicated through the bevel gears 54 and 53 to the eccentric weights. The aggregate immediately begins to be bounced up and down upon the mesh surface of the screen. Aggregate which does not immediately fall through the apertures in the screen is bounced away from the plain surface of the screen in a direction initially normal to or at right angles to the plain surface of the screen. After each particle reaches the apex of its lift, it will fall in about a perpendicular direction or arced slightly toward the left. The particle will consequently strike a point on the surface of the screen further down the slope from the point on the surface which it immediately left. Upon the next bounce the particle will be lifted again from the surface of the screen in a direction which may be presumed theoretically to be at an angle equal to the angle of incidence of the particle when falling into contact with the screen. Particles thus progress down the slope of the screen and those sufficiently small in size are worked through the mesh of the screen. Larger particles are permitted to fall from the lower end of the screen.

Under circumstances where screen of different mesh size is used on the top from that used on the bottom, the screen on the upper portion may be of finer gage than the screen on the lower portion. Hence, small size particles may be readily screened in the upper portion of the screen and after the majority of the smaller sized particles-have thus been screened out, a coarser screen on the lower portion will be enabled to screen out coarser or larger particles. Suitable conventional dividers may be installed beneath the screen and frame wherever necessary in order to separatethe finer screenings from the coarser screenings. Under such circumstances the eccentric weights 65 and 67 maybe adjusted at the upper end of the screen at a position more aptly suited to the screening of finer particles, whereas the weights 64 and 66 at the lower end of the screen may be adjusted to more suitably screen coarser particles. The weight of the eccentrics may also be adjusted to a greater or lesser amount in order to best accommodate the particular type of screening being performed by one end or another or even by both ends of the screen.

Although a longitudinally arched screen may on some occasions be found more acceptable, there has been shown for illustrative purposes a longitudinally and transversely flat screen inasmuch as the principle of operation is substantially the same. "Should it become necessary or desirable to substitute one screen for another, the substitution is readily accomplished by loosening the hooks 36 so that the screen and its stiffeners may be slid endwise with respect to the position of engagement and a new screen having different mesh characteristics may be readily substituted by being slid into place and ultimately tightened by the tightening of the hooks 36.

There has thus been described a very convenient and simple adjustable screen device which by virtue of its suspended mounting minimizes shock upon the supporting frame to a degree permitting the screen to be made relatively light in structure without impairing its efficiency or long-time use. The manner of suspending the screen moreover makes it possible to impart to it virtually any degree or character of vibration within the scope and limitations of the eccentric weights which can be employed thereon and furthermore makes it possible to use and enjoy such varied character of vibration without at any time disturbing the driving mechanism which continues in good adjustment under all conditions of vibratron.

While I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

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

l. A vibrating screen device comprising a sloping frame having resilient supports, a charging end and a discharging end, a screen extending over said frame, and adjustable vibrators on each side of the frame comprising parallel shafts extending in a plane parallel to the plane of the screen and eccentric weights on the shafts mounted for rotation in opposite directions and shiftable longitudinally relative to the respective shaft, and anchoring means operatively associated with each eccentric weight adapted to secure the respective weight in a selected position of adjustment with respect to the supports thereby to fix the vibration characteristic of the screen in one of a variety of adjustments.

2. A vibrating screen device comprising a stationary support, a free swinging frame having a charging end and a discharging end, a resilient suspender at each end secured to the stationary support, and a screen extending over said frame, a transversely disposed drive shaft at one end of the frame and a power drive therefor, and adjustable vibrators on said frame comprising a longitudinally disposed driven shaft on each side of the frame connected to the drive shaft whereby the driven shafts are adapted to be driven in opposite directions, and an eccentric weight means for each shaft, each weight means being slidable with respect to the respective shaft and tightening means between each weight means and the respective shaft adapted to secure the weight means in a selected position of adjustment with respect thereto.

3. A vibrating screen device comprising a stationary support, a free swinging sloping frame having an upper charging end and a lower discharging end, a resilient suspender at each end secured to the stationary support, and a screen extending over said frame, a transversely disposed drive shaft on the charging end of the frame and a power drive between the drive shaft and a source of power, and adjustable vibrators on said-frame comprising a longitudinally disposed driven shaft on each side of the frame, gearing connecting each driven shaft with the drive shaft adapted to drive the driven shafts in opposite directions, and a pair of eccentric weights on each end of each 'shaft, each weight having a sliding fit upon the respective shaft and tightening means between each weight and the respective shaft adapted to secure the weight in a selected position of adjustment on the shaft thereby to fix the vibration characteristic of the screen in one of a variety of adjustments.

4, A variable vibrating screen device comprising a support, a sloping frame having a resilient connection to the support, a screen on said frame having a mesh of one character at the upper portion and a mesh of another character at the lower portion, a pair of driven vibrator shafts mounted longitudinally on the frame, adjustable eccentric weight means slidably mounted on each shaft with the weights on one shaft facing eccentrically in opposite directions from corresponding weights on the other shaft, said weightsbeing adapted to be moved each to a selected position of adjustment longitudinally relative to the frame, and tightening means between each weight means and the respective shaft adapted to anchor the weight in a selected position of adjustment.

5. A variable vibrating screen device comprising a support, a sloping frame having a resilient connection to the support, a screen on said frame having a mesh of one character at the upper portion and a mesh of an other character at the lower portion, a pair of driven vibrator shafts mounted longitudinally on the farme each having a connection thereto at the mid-portion and adjacent the ends, adjustable eccentric weights slidably mounted on each shaft with the weights on one shaft facing eccentrically in opposite directions from corresponding weights on the other shaft, one of the weights on each shaft being at an upper portion of the shaft and the other of the weights being at a lower portion of the shaft, said weights being adapted to be moved each to a selected position of adjustment between the adjacent end and the connection at the mid-portion, tightening means between each weight and the shaft adapted to anchor the weight in a selected position of adjustment, and drive means adapted to rotate the shafts in opposite directions.

6. A power operated vibrating screen device comprising a support, a sloping frame, free swinging supporting means for the frame on said support initially biased toward one end of the frame, a drive shaft means mounted rotatably and transversely on the frame, a belt wheel on the drive shaft, and a flexible endless drive from a stationary source of power to the belt wheel, said drive being maintained in a constantly tightened position of adjustment by the weight of the frame acting against said bias, a shaft mounted on the frame in a position transverse to the direction of the drive shaft and an eccentric weight on said shaft, said shaft being in a direction generally parallel to the direction of the endless drive.

7. A power operated vibrating screen device comprising a support, a sloping frame, free swinging resilient suspending means between the support and the frame, a longitudinally disposed driven shaft means on the support extending transversely to the suspending means at one end of the device and including at least one eccentrically mounted vibrator weight, a drive shaft means operably arro'mso connected to the driven shaft means and mounted transversely atone end of the frame, a belt wheel on the drive shaft, and a belt drive from a stationary source of power to the belt wheel attached in Va position wherein the frame is swung toward the source of .power out of vertically suuspended position, said belt drive being maintained in a constantly tightened position of adjustment by the weight of the frame and parts mounted thereon.

8. A vibrating screen device comprising a sloping frame having resilient supports for the corners of opposite side edges, a screen extending over said frame, parallel shafts extending in a direction parallel to opposite side edges of the screen between corner supports at opposite ends of the corresponding side edges, and an cecentric weight device on each shaft shiftable longitudinally relative to therespective shaft to different positions relative to said supports at opposite ends of the corresponding side edges, and tightening means between each weight device and the respective shaft adapted to secure the weight device in a selectedposition of adjustment and means for simultaneously rotating :said shafts.

9. A vibrating flat screen device comprising a frame mounted at an oblique angle relative to horizontal and a flat screen extending over said frame, a resilient support for said frame on opposite sides, a pair of shafts mounted on the frame parallel to each other and to ad jacent edges of the frame, said shafts being positioned in substantially the same plane as said frame, at least one eccentric weight for each shaft having an adjustable connection upon the respective shaft adapted to be anchored to the shaft at a selected position of adjustment between opposite ends and a drive connection to said shafts.

10. A vibrating screen device comprising a frame means having longitudinal and transverse axes, a resilient support for the corners of opposite side edges of the frame, a screen extending over the frame and adapted to receive thereon material to be screened, vibration inducing .means comprising a pair of shafts parallel to .each other and in a plane generally parallel to the plane of the screen, at least one of said .planes being tilted at an oblique angle downwardly toward a discharge end, an eccentric weight device on each shaft, the weights being arranged to oppose each other when in .laterally extended position and augment each other when in upper and lower extended positions, and means for simultaneously driving said shafts in opposite directions.

ll. A vibrating screen device comprising a frame means having longitudinal and transverse axes, a resilient support for the corners of opposite side edges of the frame, ascreen extending over the frame and adapted to receive thereon material to be screened, vibration inducing means comprising a pair of shafts parallel to each other and in a plane generally parallel to the plane of the screen, at least one of said planes being tilted at an oblique angle downwardly toward a discharge end, an eccentric weight device on each shaft shiftable longitudinally relative to the respective shaft to different positions, tightening means between said weight device and the respective shaft adapted to secure the weight device in a selected position of adjustment and wherein the weights are arranged to oppose each other when in laterally extended position and augment each other when in upper nad lower extended positions, and means for simultaneously driving said shafts in opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS 1,071,706 Combs Sept. '2, 1913 1,685,941 Deister Oct. 2, 1928 1,779,454 Traylor Oct. 28, 1930 2,062,529 Sahut Dec. 1, 1936 2,068,730 Behnke Jan. 26, 1937

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