US1616472A - Screen - Google Patents

Description

Feb, 8,1927. I 1616472 A. H. STEBBINS SCREEN Filed-Feb. lO, 1926 2 Sheets-Sheet 2 vUnire srv-f This invention relates to screens, and more particularly to a'novel `construction for preventing clogging ofthe screening apertures.

Much vdifficulty is vexperienced in operating apertured screens due to the Vtendency of the larger particles to lodge vin the screen apertures and clog the saine; and in an effort to overcome this difficulty various'forms of operating means have been proposed for l.shaking the screening surface With sufficient force to dislodge the clogging particles. This method of preventing clogging is Open to the objection'that the' energetic movement imparted to the screening surface to dislodge the particles from the apertures may seriously disturb the proper sifting ior screening operation. V

The present invention therefore lrelates to a screen the screening' surface of which is so constructed that the materials being' treated are prevented from lodging in the apertures to clog the same.

.One important feature ofthe yinvention resides in a screen surface having screening apertures in the form of slots thatincrease in Width lin the direction in v`which they extend so that the particles that lodge inthe slots may more readily slide therein` `inthe directionin which the Width of the slot increases.

Another important feature of the'invention resides in the arrangement of-deflectors having inclined Walls yadapted to force the particles out of the slots in Vwhich they have become lodged.

Another feature of the invention resides in the construction of the material supporting surface whereby the materials vbeing treated are directed 'toward the apertures by sloping Walls.

Otherfeatures fof the vinvention and novel combination of parts in addition to thel above vwill be hereinafter' described in connection iviththe vaccompanying drawings Whichillustrate one good, practical form fof the invention.

Fig. 1 isa top plan View of a screen .constructed in accordance with the present invention; v

Fig. 2 is a side elevation of the screen of Fig. 1v shown Inountedupon a support-ing frame and part of the screen casingbeing ing surface g y .'Fig. 3' ie perspective 'vietaj looking? tm screening surface.

broken away to show the material support` SCREEN.

10, 1926. `Sera1-No. 87,379.

Ward the discharge end of the yscreen vshown in Fig. 1;

Fig. 4L on an enlarged scale isa sectional perspectiveview of a portion of the screening surface of Fig. 3;

`F ig. 5 on an enlarged scale is a top plan View of a vportion of the material support-v ing'surface ofFig. 3;

Figj is a vertical sectional viewthrough Fig. 5; and v Fig. '7 is an end view of a modiiied'screen constructionfhaving an upper and a ylower The Screen casingwhich supports the screening surface formed in accordance With `the present-invention may be Agiven any de Y i sired construction and various'means vmight -loev provided for supporting the screen casing and for imparting la vibratory movement to the same. 1

The screen casing shown inthe drawings is pro-vided With theffloor 10 upon which .the liner materials fall uponfpassing through the screen surface. At the opposite sides of the floor 10 are provided the sidewalls 11 ,and theframe casing is shown asV being rectangular in shape and has theffeedlhopperv 12 provided atthe left-hand end thereof. The rate'at which the materials flow from -the feed hopper to the screening surface may be' controlled by adjusting the gate 13. The 4floor 210 of the casing lis 'preferably mounted upon a carriage .or supporting frame conveniently formed of the angle irons 14 disposed at'each sideA of the casing and extending'lengthwise thereof, and these angle irons may be connected bythe transversely extending braces 15, constituting-a rigid frame which will support and-strengtheny the casing.

The scr-een casing-'shown lnFig. lis preferably mounted 'for "vibrato-ry movement in' Y the'directionof its'length and itmay be supported in a horizontal plane, but in vmany "cases -it will be found Vdesirable to incline the screen in the direction of itslength to thereby 'promote travel of the materials `lengthwise 0f the casing toward the" righthandl end thereof,vievving Figs. 1 and`2. In

' some 'constructionsl it may evenbe desirable 'to inch-ne the 'screen Ycasing 1n the opposite direction to impart a slight uphill movement to the materials as they travel lengthwise of the screenin` surface.

` Vario-us coiisfructions might beprovided forrnnnm the screenffmme-upon a sup Vporting base for back and forth movement Vand the supporting means shown comprises Yio a Vframe formed of Vthe longitudinally eX- tending beams 16 fastened to theiupriglits 17jand it should be. noted that the frame slopes in the direction of its length to support the screen casing* at 'an` inclination which will advance the materials lengthwise of'tliescreen, as clearly shown in Fig. 2. Various means Ymight be proyided for supl porting the screen casing for movement back and forth-iii the direction of its length, and

the means shown ,consists of balls or rollers 18Y resting in the bearing blocks 19 mounted uponV the supporting base, and the Vupper portion of these balls lor rollers are received in bearing blocks 2() secured to the side rails la of the casing.

Y It is desirableto impart a vibratory movement to the casing'to promote Vtravel of the.

Vmaterials lengthwiseVV of the Vsame and also topromote sifting ofthe finer materials through the apertures'fof the screening sui'- Y face. To this end either a simple, vibratory movement, or a progressive, vibratory movement Vmay be employed, and the operating meansl sliowiiconsists off a cable 21 having Van intermediate portion rigidly securedk to the casing by any suitable construction, such as the clamping block 22. @ne portionV ofk the cable extends from the clamping block Y A 22 Vin a .right-hand direction and is bent around `the grooved slieave 23 rotatably supi Y ported by the transversely extending shaft .Qflsuipported by the base of the machine and this cable extends downwardly from the Vslieave 23 toa yielding anchor which may consist `of a coiled spring 25 which is conlined between a transversely extending beam y26 of the supporting casing and an enlarged heador'nut 27 secured to the end vof this cable.- The portion'of the cable 2l extend- Ving in a left-hand direction from the clamping means 22-passes around a grooved sheave 28 mounted'upon an eccentric 29 which eccentric is securedto or is formed integral with the operating shaft 3 0- wliich shaft may be driven by Ya pulley (not shown),

' yfo and this shaft is rotatably supported by bearing brackets ill-secured to the supporting frame. This cablev extends from the l lower side of theV sheave 28 to anchoring means suoli as a bolt32 fastened to a transverselyextending beam by the nuts 33, and

Vthe length of the cable 21 may be varied as desiredby adjusting the nuts 33.

Theoperation of the construction just p described is suchthat theV spring 25 will "continuously *urge the material supporting Y portion of thel cable 2l extending` aroundk casing in a right-hand direction, and thev the sheave 28 will be alternately ytensioned Variel slacked off by theeccentric 29 rotating within this sheave. This will serve to tension the cable to pull the screen casing in a left-hand direction and then slack oil' the cable to permit the casing to move in the right-hand direction under the action of` the spring 25. Should it be desired to increase the progressive nature of the movement imparted to the casing by the means justdebe formed of sheet metal or other suitable material, and extends across the casing between the opposite sides ll thereof, as will be apparent from Fig. 3. The surface so constructed' that itforins a series khills and valleys extending lengthwiseV the casing and having the inclined walls vwhich meet at their upper edge to form the ridge 3S, yand slope downwardly toward each other to produce the valley provided with the aperture or opening .39 through which the finer' materials may pass to fall upon the l floor l0 of the casing.

lNithin each valley formed by the sloping walls 37 is mounted a roof 4l() having, the downwardy sloping side Walls lll, and each roof is supported over and iii spaced relation' to an vopening 39. These roofs, Vas

soV

shown, areformed of thin material suchVV as sheet metal, and are held in spaced rela-` f tion to the lower portion ofthe valleys by postsV 4t2. TheV parts are conveniently secured in place by the bolts 43 whichV mayV extend through drill holes formed in the roofs and posts, and may be clamped in place by tightening the nut 44 at the lower end of eachbolt, and which rests against a V-shaped block lthat engages the lower face of the ysupporting surface p j llD The posts 42 serve to support the roofs n so that the lower edgesof these roofs lie in spaced relation` to the sidewalls 37 to forni the material receiving slots le between vthe lower edge of these roofs and the side walls .37. It is Vapparent that the inclined walls '37 and l1 will direct the materials downwardly toward the slotslGV to promote the passage of the finer materials through these slots, and the sifting or screening operation iso of thesey materials will be assisted by the vibratory movement iinpartedto thescreeii 'i casing. Y n Y The larger particles which enter the slots +16, and which are too large to pass therethrough, inay tend to become stuck in these slots,v and in order to prevent this,I inV accordance With the present invention, the

construction of the slots `46;.'is preferably such that they increase .in width in thedirecf; tion in which the materials travel lengthwise of thecasing. This.,increase in Vthewidth of the slots 46 may be readily produced by arranging the Vroofs 40 in the overlapping i'elation best shown in Fig. 6, `wherein itl will be seen` that the left-hand end ofone roof rests upon theupper end .of a post 42, A'while the rightfhand end of this roof overof, successively tapered portions so that when the width of the slot at theend of one section thereof has reached the maximum size desired, the slot may be terminated and the materials may pass on to the ynext tapered slot of similarl construction, and in alignment with the first slot.

Itis important 'to provide means for forcing thelarger particles'withinA a `slot out of thesamezas these particles approach the end of one of the tapered sections; ths is readily accomplished in accordance with the present invention by constructing` the posts p42 to form deflectors having f the inclined walls47; thatis, these posts, aswill be apparent fromlFig. '5, are given a wedgef shaped construction with thek narrow portion ofthe. wedge extendingtoward the material receiving end of the screen casing. As a result of this construction, the larger particles designated by m as lying within a slot 46 and traveling lengthwise thereof under the influence of the movement imparted to the supporting casing, will engagea sloping side wall 47 of a post and willibe lforced out of the slot, as will be apparent from FiO. 5. ln this manner all danger of the slots 46 becoming clogged is avoided.

The fine materials which sift through the slots 46 and fall upon the bottom l() of the casing will travel lengthwise of this Hoor to the tapered discharge hopper 48 having a downwardly extending pipe 49 which may be connected with a material receiving receptacle by the flexible tube 50. The large particles which fail to pass through the slots 46 will travel lengthwise of the apertured surface to be discharged from the riglit-hand end of the casing, viewing Fig. 2, and slid down Athe discharge board 51.

A screening casing constructed in accordance with the present invention may be provided with a single screening surface such .valleys mountedJin'tlie valleys over said openings as 36, as shown in Figs. 2 and 3, or may have two.V screening lsurfaces 36, positioned one above the other. asshownin the modified construct-ion of Fig.. 7. i K,

x a From the vforegoing description, when read in connection lwith the'drawings. it will .be seen that the sloping sidel vwallslantl the sloping` roofs 40 serve to direct thematerials toward the slots.46, and that tlievtapered construction of these slots .promotes travel;

lengthwise of theslots ofthe larger particles 4which tend to become wedged therein. lt will also .be seen vthat these largerparticles which tend to lodge in a slotV will travel lengthwise therein until they .engage Vthe.`

sloping side walls 47 of a post, `whereupon they will be forced Vout of the slot by the venting the slotsfof the screening surface from becomingrlogged.

, lVhat is claimed is:

1. A scre-en,.comprisingin combination, a

casing providedavith a materialsupporting surface constructed to form a series of hills 'and valleys extending .lengthwise of `the casing and having .sloping side -walls andv material .discharge openings'formed inthe between the j side walls, roofs .tapered VconstructionYof the post,`thus prc- Yand having edges that. lie in spaced relationto said sloping walls, each'roof being formed of aligned .sections having their ends over-' lappedl to. provide. tapered .material receiving :spaces between the sections` and side `walls vwhich increase in width throughout .thelengthof each section,..but do not increase in width continuously throughout the length of the valleys, andmeans for imparting movement to the materials being treated .tosift the. finer inatei'ials through1 the slots formed between said edges and the sloping side walls.

2. A screen, comprising in combination, a casing, a material supporting surface supported by the casing and constructed to form a series of sloping side walls having material discharge openings in the valleys between the` side walls, roofs mounted in said valleys above the openings and having side edges that lie in spaced relation to the sloping side walls, wedge-shaped blocks mounted in the valleys at intervals along the saine and having tapered sides disposed to force out of the slots the large particles that tend to lodge therein7 and means for advancing the materials over said surface -to sift the finer materials through they spaces betlween the edges of the roof and sloping wa ls.

3. A screen, comprising in combination, a

casing provided with a material support` to form vmaterialreceiving slots toward which the materials are directed by the slope of the roof and theslopevof said Vside walls,

each roof being formed of aligned sections having theiredges positioned to Jform suc-v cessively tapered material.. receiving spaces l between the sections and side walls l'which increase in width throughout the lengthv of each sectionv but dol not? increase Vin width continuously throughout the length of the valleys, and means for imparting movement Vto the materials being treated to sift the Y y line materials through said slots.

4. A screen `for separating materials comprising in combination, acasing provided with a material supported surface having a series of oppositely sloping side walls con Vstruct-ed to form material discharge openreceiving slots therebetween, said. slots being formed of aligned successively tapered portions that increase inwidth in the vdirecf tion in which the materials travel along the slots, deilectors positioned to .torcev out of the slots the large particles that tendto lodge therein, and means for advancing the inaterials along thesupporting surface tovsift vthe finer materials' through said slots.v

5. A screen, comprising inzcombination, a

- casing mounted for vibratory movement and u provided `with a material supporting surface having a series of `sloping side walls and material discharge openings in the valleys between the side walls, roofs mounted in .the valleys over saidopenings and having side walls to form material receiving slots toward whichthe'materials are directed by the sloping walls, deiiectors mounted beviieath the roofs and having tapered sides adapted to force out of the slots the large particles that tend to lodge therein, and

means for vibrating the casing to advance the materials lengthwise of the same.

6. A screen, Vcomprising in combination, a casing mounted for vibratoryniovement and provided with a material supporting surface.

constructed to form hills and valleys veX- tending lengthwise ot the casing and having discharge openings formed in the valleys, roofs mounted in the valleys over said openings and having side edges 'that are spaced from the sloping side walls oft the valleys to iormdischarge slots, posts ior supporting-the roofs and having inclined `side walls adapted tofiorce out of the slots the large particles that tend to lodge therein,

and means for yvibrating the casing to advance the materials lengthwise of the saine.

T. A screen, comprising in combination, a casing mounted for-vibratory movement 4and provided with a material. supportingsurface constructed to form hills and valleys eX- tending lengthwise. of thej casing, roofs l mounted lin the vvalleys and supported in spaced relation tothe sloping sidewalls of the valley to form material receiving slots op through which th-e line materials may escape, Ydelectors.mounted adjacent said slots and having tapered walls to force out of the slots the heavier particles that tend to lodge therein, and means torV advancing the materials along the supporting surface.

In testimony whereof, I have signed my naine to this specification.

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