US2443543A

US2443543A - Screen clearing mechanism for grain and seed sizing machines

Info

Publication number: US2443543A
Application number: US587717A
Authority: US
Inventors: William J Peterson
Original assignee: SUPERIOR SEPARATOR Co
Current assignee: SUPERIOR SEPARATOR Co
Priority date: 1945-04-11
Filing date: 1945-04-11
Publication date: 1948-06-15
Anticipated expiration: 1965-06-15

Description

June 15, 1948. w. J. PETERSON 2,443,543

SCREEN CLEARING MECHANISM FOR GRAIN AND SEED' SIZING MACHINES F11ed Apri1 11, 1945l 5 sheets-sheet 1 m Invem'o Hmmm J- Pe'rensom ATfoaNeYs June 15, 1948. w. J. PETERSON 2,443,543

SCREEN CLEARING MECHANISM FOR GRAN AND SEED SIZING MACHINES Filed April 11, 1945 5 sheets-sheet 2 l WILLIAM J. Pere-aso AT1-amava.

June 15, 1948. w. PETERSON SCREEN CLEARING MECHANISM FOR GRAIN ANI) SEED SIZING MACHINES 5 Sheets-Sheet 3 Filed April 11, 1945 WlLuAm J. Pen-nso June 15, 1948. w. J. PETERSON SCREEN CLEARING MECHANISM FOR GRAIN AND SEED SIZING MACHINES Filed Apil 11, 1945 5 Sheets-Sheet 4 Wmmri Lft-Temas June 15, 1948.

w. J. PETRsoN 2,443,543

SCREEN CLEARING MECHANISM FOR GRAIN AND SEED SIZINGMACHINES Filed April 11, 1945 FMEA?,

5 shets-sheet 5 gmc/Www WxLLlAM J.' Pen-naam Patented June 15, 1948 UNITED STATES PATIENT lf'oFFiczE i1 "This ."invention relates 4to improvements 'in machines forsizing grains or seed; and particiinlarlyfror."separating seed corn'i'nto anumber "ofclosely `and doub'lydimensioned sizes to' facili- "'tate'its "planting,

" 'The' inventionhasfparticular' 'reference to" that 1 typl 'f's'ch machines "wherein a ".'plurality` of 'perforated sf':ree1"is"fare "assembled" insh'oes "and Vthe Whole vibrated both to travel"themateria1 ovef'the screensandto cause' "the" material to f and'sepa'ratinglcontact With 'the' 'openings'in'the screens. Asits rimaryobj ect myinvention aims `to generally improve 'such machines toA facilitate l and' improvetheir operation.

'An'other fandimportant objectis' to`z'proyide 'Vanimproved'lly "adjustable screen 'clearing 'or r cleaning 'l mechanism by' 'which the 'screens' may be kept clear of all "lodgedV kernels "'ori particles and so" that the' 'machine mayoperate 'at all times at .fiill capacity.' 'This' has long beenaproblem A in thisiield, lsince Ythe"screens" in making *closely lsized -`sezvarations have a pronouncedv tendency 'to yclognip,l due to .thelldg'ement vof particles.' iri'the peningsg-/and unless this 'is yeffectively"counteracted it sapparent" that the --'fli'ciencyrof"'Ithe machine willffdiminish lrap'idly. In accordance with my inventior'il'proifide a mechanism Where- 'in the undersides `if-"the'rxiachine -arec'ontinually wiped and'atthe same" time upwardly'tapped 'or "struclibyWi-pe'rbars which are not only power actuated ortraveledito lWipe andcontact allareas fc-Affthe screens; but are also .f power vibratedor A oseillated toeupwardly tapthe' screenand so dislcdgeany'lernels'br' particles from the openings. In connection 'with' the'latter 'feature-vl of my invention, that ofiwer' oscillatingithe'*cleaning 4 bars," I also-embodyishockabsorption" means of such-nature as tdprotect 'the'i-screens from -hard f blows and to `alloW""theWi1er bars to clear` kernels or particles falling'tli'roligh the'wscre'ens Yand'so ,l prevent any injury to the seed `or grain.

y "These and other'moredetailed,andspeciflc obi :jects will beiii'sclosgdinthecourseff 'the fin-110W- ing spec'iification, r'e'fere'ncebeing had'to thel accompayingidrawingsjinwhichfeig." 1 is e' sidemelevation'rof'my improved ma- -ciuine Z is a SimilarViW'butdookng 'at'the-other sideff the macl'ne,

#Claims (Cl: 1209-1382) Figi 5 i-s-Lanienlarged?fragmentary detailyiew'of one* *Wiper `elementiiardll lak-'part'. of 4Lits actuating *mecha-mism.

Figi-E6 fis :alve'rtical :longitudinal sectional View 5 `Athrong-h the vr'na'cil'iine but only fthe' uppermost screens bei-nglis-hown in section, 'fwhile the shoe carrying Ithe lower screen is fsh'own .inelevati'on Figi 7 isan-le'rlilargled fragmentary:sectional l0r sential-andifdrive'mechanismfor the wiper. struct1-1re.

Figi 8fis a det-ailf--secti-onalview alongi thelline -S in Fig. '7.

"Figv 9 veisean enlarged :fragmentary-.sectional V'view''snbstarrtiazllyifalon'gthe liner-949 in'Fig. 6 k-but also -showing adj acent parts.. of the Wip ery :op-

'erating" mechanism.

A"`r'tef'er'ririgfrrovsr'more#particularly .and by refer- "ence -charactersto'fthe ldrawingg'my; machine as Lshown-tlrerein'cormgirisesia main; frame cri frame- Work havinguprightccirne `Vposts' I irigidly joined by cross bars N at upper dlowerendsiand ccnnectednti yupper er'rds -byl '-horfizontalzzupper iframe 'seen in -Fig.' 1,11the 'lowestends'cfv said'bars` being 'i located1 at" the delivery.endifoi'the' .machine -as a "Supporte'dhy land'Within'i-this framework are uppervand?lowerlsho'espdesignatedgenerally 'at l i and'fl 'fwhich "are arrangediin superimposed if'ffithel delivery endJc-fthamachine. The shoes frame havingsidesfl', rigidly connected together as Will later appear, and saidfsideshave suitable screens'f I lrfaiidSI-S are supportedy Ionefabove the 401 ttlier.' lSince thespecicv screen mounting forms vrio-:part1ct"rnylpresenirinvention it is not rdetailed herein;-itfbeingfmerely noted that thezscreens Il and-"fl Slmay-be' -slippeden'dwise into.y the shoes betweenthesidessl thereof andfremoved therefrom -1ifat= will. Fors thispurposethe' higher or feed ends -lffofy the'S'sho'esn-arel proVidedwi-th removable end "--pl'atesI I9 (Figf): aligned-With thef screens and "i vihicl'i.:mayfy bei removed vwhen e the a screens are ebein'g iclianged. Mother 'permanently mounted end plates 23 securer the 'slloey sides i5 together at this'iend. t

"Forcorin :'gradingf"each-screenl I1-and It is '-Smader in two i sections, onery section indicated at Ila and ISa for each screen having a screen making width classifications of the corn, and the other sections, indicated at IIb-|81, having screen plates punched with elongated holes or slots 22 (Fig. 3) for making thickness classi-- cations. Each screen section has a separate rectangular frame 23 to which the perforated plates are fastened.

The screen arrangement and gathering kmeans for the various classications of the corn as here shown are largely conventional and will accordingly be only briefly described. The round holed screens Illa-I3a are arranged to receive the corn first and the corn rejected by'these screens is caused to travel down lengthwise over the corresponding slotted screens IIb-ISI. A hopper 38 is provided as the feed means for the upper screen. The corn rejected by the screens is taken off through

delivery spouts

24, 25, 26 andV 21 respectively. The throughs from the uppermost screen I'Ie are carried back to the head end of the screen I3EL next below by a return pan 28 disposed below the uppermost screen and which slopes back in the direction of the feed end of the machine. In turn the throughs fromscreen I 8a are collected by another return pan 29 and carried back to the head of the upper round holed screen in the lower shoe I5 and the action is repeated therein until the lower round holed screen is reached. The throughs from this screen are delivered in the usual manner from a laterally extending trough 39 (Fig 2) attached to the lower shoe. 1

The throughs from the slotted screens IIb- I8b in both shoes are collected on bottom plates indicated generally at 39 and separately delivered from the ends of the shoes by

spouts

3l, 32, 33 and 34. All of these end spouts are conveniently fastened, as indicated at 35, across the ends of the shoes at proper levels to receive the various grades of corn, and serve also to tie the sides i6 of the shoes together.

As seen in Fig. 6 the throughs from the upper end portions of the upper three slotted screens IIb-I8b may be collected by laterally discharging troughs 36 and delivered separately from the corn emerging from the spouts 3I `to 34. Thus the screens I lb-I 8b may, by using slots of different width at upper and lower end portions, each make three separate classifications. As a result, the four layer or four deck machine here shown is seen to make no less than twelve size classifications of the corn. I do not, however, limit the application of my present invention to this specific screen arrangement since it may be varied according to the kind and class of grain or seed being sized.

To progress or travel the corn or seed over the screens and to cause it to bound about thereon as required for proper operation of the machine I provide means for shaking or vibrating the shoes I4 and I5 as will now be described.

The upper shoe I4 is supported for lengthwise swinging movements by flexible metal straps or hangers 49, one at each corner, and lower ends of these straps are secured at 4I to the shoe sides I6. The upper ends f the straps are secured at 42 to the upper part of the main frame. The lower shoe I is similarly supported at each corner by straps 43 secured at upper ends at 44 to its sides I6 and secured at lower ends at 45 to the lower part of the frame. Thus the shoes may be vibrated or swung lengthwise independently of each other.

The shoes are thus operated, and the entire machine powered, by any suitable prime mover or power source, such as an electric motor 45, belted as at 47 to a pulley 48 on a main drive shaft 49. Said drive shaft 49 is journaled in bearings 5I] supported on the corner posts I9 at the feed end of the machine, and the motor is pivotally hung at 5I on the frame to keep the belt 4'i' taut. f

The drive shaft 49 carries near each end a pair of eccentrics indicated in Fig. 6 at 52-53 which reciprocate eccentric arms or pitmans 54-55 adapted to be respectively connected to adjacent corners of the upper and lower shoes I4 and I5.'

' p As one way of connecting these parts I show the pitmans' 54-55 as connected to flexible straps 56 and 51 which are in turn bolted as at 59 to the shoes. The arrangement is obviously such that the rotation of the drive shaft 49 and the eccentrics 52-53 thereon will swing the shoes I4 and I5 back and forth through a limited range, and with the eccentrics located oppositely as here shown with respect to the axis of the shaft 49, the shoes will move in opposite directions. The speed of this movement is such that a pronounced vibration of the screens and the seed or corn thereon results, and I have found that a rate of vibration of 400 per minute, and a range of one-half inch gives good results for most purposes.

My present invention relates to the screen wip-- ing and clearing mechanism now to be described. For the four screen layer or four deck machine herein shown I provide at each side thereof a carrier frame comprising four parallel and vertically spaced bearing or carrying bars 59, Gil, 6I and 62 secured together rigidly by upright bars 63-54 connecting their ends. The bars 59 through 52 are located parallel with and below the level of the respective screens I'I--I8 within the two shoes I4 and I5 and, of course, slope vtoward the delivery rend of the machine. The grid-like rectangular frames thus formed at each side of the shoes, are supported for reciprocating movements lengthwise of the shoes and parallel with the screens b y two upright supporting bars or

support members

65 and 65 at each side of the machine and which are spaced apart lengthwise thereof. Near upper ends these

bars

65 and 66 carry peripherally grooved pulleys or rollers 5l over which the uppermost bearing bars 59 ride and these pulleys are located at proper and different levels so as to support and guide the carrier frame for movements in the desired sloping, longitudinal plane. As seen in Fig. 9 the bars 59-62 are made from angle irons and to guide the frame on the pulleys 61 and hold it thereon short sections of rod 58 are welded inside the angle of the upper bar (Fig. 2) to ride the grooves of the pulleys.

The manner in which the supportin-g bars E5 and 63 are themselves supported will be described later.

Each of the bearing bars 59, 59, GI and 52 at each side of the shoes carries six, more or less, spaced bearings, designated throughout at 59, and in each aligned pair of said bearings on the opposite sides of the frame a wiper or rocker shaft 'I9 is journaled. There are, accordingly, twenty-four of the shafts 'I9 in the machine here shown and' they are supported by the bearings transversely beneath the respective screens I'I-I8, with three of the shafts located beneath each round holed and each slotted screen. To pass the shafts the sides I6 of the shoes I4 and I5 are provided with openings 1I and these openings are not only elongated in the direction of the ---lengtheofithe-` machine towperamt. the shaf ts f to move'backcand-frthf With-the carrier* framesibut aresofwdervrtiallyeas 'to per-mit ysubstaritaliup a-idfldown adjustments off'- he: shaftslaswill-preswhich extern-'parallel' with the shafts `aud-i cross -H 'fWi-sewth respect-td thescreensf- Preferablyfthese fwwipeebarsd'- "M -are of-rubber or-other vresilient v material 'ar'id'ft'hey arebf #such "length asl' to fsub fstantiaflly completely" Sloan the lscreens'crosswise *The entire carrier'frame 1'inclu'clirigf"the wiper.;

shafts and bars fareipower travelled'to' 'cause the f-barsto 1wipe undersiozesof-"theTrame-iasI will now ing"brafcketli16crosswise of 'the' lower frame barst A crankshaft 86 is journal-edin'bearingi'brackets il if' in--the lower -part of the f frame *parallel-"With Y .lightedfsprocketsfZ"arid-333 ""(Figf) ^over which isi trained a sprocket chain 84. -Thearrar1ge ement-is such thatthe crankshaft is driven by 'Y vthe-motor'156` but' at a relatively slowj speed. l A

meeting rodi 236i which extends lout --tothe f eed. end -=of-=the machine and is -upivota'llyconnected at" 8'! f -'-toithe lower end'cf a crankf'a'rni" 88. This-crank arm 88 is secured to a rock shaftfS-joumaled well below the drive -shaftfll in bearing brackets* 3B secured to the Vadjacent frame corner` posts WIB. -4:Said'sliaft 33: alsoizcarries: cr-rop'erates' upumwardly ri exteihding.Y crank. Alevers? 9 iii al-ignedfwth the:ladjacent'vienda'bars it/'ofi 'thefswiper' carrier Y "frameiemdi-the: respective' crank armsfatteach-i` .asiden of the frame-areconnected to said-barsf f Abyff'lrik rods'e2. It Wil-l be readily: apparentfthat the aforesaid, rotation of the'r` crankshaft 80 4will causefthefcrank"leversff l; to'-.osc`ill'ate iinupright :filongitueinal planesaa'ndj thisfimovement 4will tbe E'lpfb-eing lguided therebyisothat "the wiper." bars* ffMrtravelfback-:and fortl'r'pathsparallel vwithutloe screens, atheamplitude of @this `movement',I or :v stroke, is isu'ch' '1 that"A the Lwper v 4barsiiwillr 'fcoll'ectivelywiper or cover 'thefull -length o-the-:screens under-surfaces. Thestroke' is. adjustable` by zthe? 1 power'f'driven;.rcking'm'echanism-whichfwillf next lbe described 'rAti'one'sside-i off fthe machine; ithat' viewedzin Fig 1 I'the "shafts fextend' fllo'eyond '.1 their. bearingsfi f and are each.'.prfwid'ed onfthis sfextended"endizwith' atfcollarf 5315 securedstofI the carries spaced outwardly turned ears` Bfprovided v'mi'itheir.-'proximate fsurfacesitawitlr; L,bring l. lAso meuntdiionflthisfiend .foffieachfifshait l0 and-eouwadlya'of".thefzcbllars 84 fis: a crankrfcr 'irockerzA arme@ 8:txrzhiclieEd'cpfendsL lost motion;.counection-betweenthefrockerfcranks 15" "ated;ihcleperrdenttfmovemorltsf of .thefshafts'finfop- :hesite 'directionsY relative"toffsaidsfcranks. The purpose of these resilient-fconnectionszendim- Vfrfportance thereof r'will presently Lbe pointed out. i.The'.rocker'icranksa shave outwardlyaturned :pins: I-Mfon'ftheirflower'fends anclxthree adjacent .ivcranks off-each =layerf, :or-'those :operatingfthe l"wiping and. .clearing vxbars ,fof eachl screen el 1 -1i 8,

connected "by connectingffbars: ori beamswl B5 which may well'y be i of .oil f impregnated wood "and 25 f provided with bearinga.aperturesetoreceivewsaid 3Dialect-ed to.-thesefends take the i'form. off-bell cranks ,-aflongitud-inal movements. of. .ft-he connecting-- bars ffthe'twee.vertical tiers of^-,rocker assembliesare UF independently.- operatival by..'the r-barstHi8- HNL .-"thewlowerI yends 7ofwhich depend below the lower eh-oe vfor operating thereat...Jllhebarsel 33e-dill] Amay also be'- offzoil. impregnated'-fwood.

. 4rranges r-between fthe. pitman" barsT .le x2-1.39

45. .isi-an; inverted: Ueehapedebridge frame H il .having 'shoes fandwhi-cbhas a-topportion .CM2 eonnect- .f ing-these :sides frame lala. accordingly 3o-moves asa unitwwith the-.carrieriramelasothe ywiping action` takes` rplace. The.. lower.rends, o ftherarneI sides F.i H l, depend below theflcwer.- .shoe

= shaft H 4 1f, is -journaled and.- 'suppor-teolf crosswise a5 rbeneaththeshoe. his shaft M Lis. driven by .1f means-01"'` a pulleyofononefendover which is trained a-belt H.leading..upxafardlyeauclxover f" hung. yfremmthe upper. frame. AAbars l 2 supporting `:tlleslfiat- Irl 8 :crosswseof .the machine .and :above leeuppershoe. kr'lfheshaft.llalso carriesfan- ,otherf pulleyl-.andf a :belt fl 2 l .leads therefrom to afr-vpuilleyflgonvthewmain .countershaft l .leep.-,tl'1e belt .f :i i taut-.arid1 fcompehsate lfor l .the travel o.- pulley l-i 5.l `with e respect to .pulley ll'clfas athe xFJvfip-erifra-mefmovesfbacklandaiorth, ll r-, provide aswmgably supported ancle-spring-Y actu-- Tomated .tigl'itenerJ-pulle;r f-lZ-I!t (Fig. 2)."y inusual-manner.

bearings |25 in which are journaledoactuating jacent the lower ends of the rocker actuating pitman bars IUS-|09. Eccentrics |28 and |29 on the shaft I I4 (Figs. 1 and 8) are provided with oppositely directed arms |3|l|3| having bearings |32 at their ends for pivotally engaging pins |33 at the lower ends of cranks |34 secured to and depended from the respective shafts |25 and |21. The rotation of the shaft ||4 will thus be seen to oscillate the shafts |26 and |21 and the ends thereof are provided with cranks IE5-435 (Fig. 1) which are pivotally connected at |31 to the pitman bars IUB-IUB so that such oscillation of the shafts will move these bars alternately up and down. As aforesaid this movement of bars IUS- |09 is translated to vibrating or rocking movements of the wiper bars 'i4 about the axes of the shafts 1|).

To keep the openings 1| in the shoes closed at all times during the movements of the wiper rocked shafts 16 I provide for each row of said openings, on each side of the machine, an elongated closure or stop strip P38 wide and long enough to completely close said openings. To accommodate the shafts 15 the strips |38 are provided at appropriate points with exible retainers in the form of pieces |39 of rubber belting or similar material held on the strips by turning their upper edges over upper edges of the pieces as indicated at |46. (Fig. 9 particularly.) Said rubber belting pieces |39 have centrally 'located apertures |4| to pass the shafts 1|) and are split from these apertures downwardly as shown at |42 (Fig. 6) so that they may be spread apart to slip over the shafts. When properly positioned the strips |38 t against the sides I6 of the shoes and they are held thereagainst by springs |43 secured to the bearings 69 and turned inwardly and downwardly to bear against the strips. Obviously then, the strips may be pulled upwardly and removed when required but when put in place they will slide back and forth along the sides of the shoe as the back and forth wiping action takes place. Behind or inside of the belting retainers or pieces |39 the strips are, of course, themselves cut away as at |44 (Fig. 6) to clear the shafts. The strips serve to prevent the escape of material from the openings 1|.

The carrier frame supporting bars 65 and (it are arranged for up and down adjustments in the following manner. At upper ends the bars are slotted or notched at |45 to accommodate bolts |46 in arms |41 which are rigidly secured to and depended from the top of the main frame. It will be noted (Figs. 3 and 6) that the

bars

bars

bars

65 and 66 and thus correspondingly adjust the entire carrier frame and wiper structure bodily.

Adjacent one end the supporting shafts |52 and |53 are provided with upwardly turned levers |58 and |59 and to the lever nearest the delivery end of the machine there is pivotally attached a link rod |66. To the other lever |56 there is pivotally pinned a strap |6| having one end turned and apertured to pass the end of the link rod |60 upon which is threaded a nut |62 by which the effective length of the rod, and hence the relative distance between upper ends of the levers |53 and |59, may be adjusted. To the other end of the strap |6| there is pivoted an adjusting rod |523 which leads therefrom out through an apertured bracket plate 64 secured to the adjacent corner post i6. This end of the rod |63 is threaded and screwed thereon is a hand crank |55. Byturning this crank the rod |53 may be lengthened or paid out to allow the supporting shafts |52 and |53 to turn in a direction for bodily lowering the wiper mechanism, while by oppositely turning the crank the shafts will be turned to lift said mechanism. The weight of the mechanism will, of course, hold the crank against the plate |64.

At one side of the machine the link bars |50 and |5| are each turned inwardly at upper ends |55 (Fig. 4) and immediately thereabove the supporting

bars

65 and 66 are provided' with tapped inwardly turned lugs B61 in which are threaded set screws |66. By turning these set screws |68 downwardly against the ends |66 it will be evident that the supporting bars 65 and |56, and the entire wiper mechanism, may be raised and lowered at one side and with respect to the other.

Operation The general operation of the machine has been described and it will be understood that the corn or other material will be caused to travel over the various screens as the shoes |4 and i5 are vibrated by the eccentrics 52 and 53. ln such travel the particles have a pronounced tendency to become lodged in the screen openings and to counteract this the wiper bars 14 are caused to move back and forth beneath the screens by the reciprocating travel of the wiper carrier frame including the frames at each side of the shoe. This reciprocating movement is caused by the crank lever 9| as has been described. At the same time the wiper bars lil are oscillated or rocked back and forth in longitudinal vertical planes causing them to intermittently upwardly tap the undersides of the screens and so upwardly dislodge any kernels or particles from the screen openings. Thus by the combination of the wiping and tapping actions of the bars 14, both power driven, it will be evident that the screens can be kept clear at all times.

Turning now to more `specific but important features of my invention it will be evident that the springs ||l| and |62 not only provide a shock absorption effect such that wear on the wiper strips and screens is reduced but furthermore that the independence of movement of the shafts 1E) and the wiper bars 14 with reference to the power actuated rocking means enable the bars to clear any falling kernels or particles which may be encountered. In other words, the wiper bars may clear any such kernels without crushing or injuring the same, by virtue of this resilient connection.

Inasmuch as the wipers must operate close to the screens for best effect they must be lowered out of the way when the screens are being moved endwise for replacement and this may be readily accomplished by turning the hand crank |65 to lower the entire wiper mechanism as a body. Also by adjustment of this crank the wipers may be raised or lowered to vary their distance below the screens and so regulate the intensity with which they tap or hammer thereon. An adequate range of movement vertically is provided for these purposes by the width of the openings 1| through which the shafts pass.

The entire wiper assembly may also be tilted lengthwise or in a horizontal vertical plane with respect to the screens by adjusting the nut |62 to vary the relative angular positions of the su-pporting cranks |55 and |56. Thus the wipers may be adjusted to bear evenly on the full length of the screens, or to strike one end or the other with greater intensity as may be required. Similarly the entire wiper mechanism may be tilted laterally or in a transverse vertical plane with respect to the screens by adjustment of the set screws |68 to raise or lower one side. The wiper bars may thus be readily leveled as required to evenly contact the full width of the screens.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modications come within the spirit and scope of the appended claims. Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

1. Screen clearing mechanism for the screen of a sizing machine, comprising in combination, a wiping device rockably supported beneath the screen crosswise thereof and including a shaft and Wiper bars connected thereto the latter being disposed transversely of the direction of motion of the screen, power actuated means connected to the shaft to oscillate the same and rock the wiper bars alternately upward toward the screen, and power `actuated means for moving the wiping device bodily back and forth lengthwise with respect to the screen and in substantially continuous contact therewith.

2. In a material sizing machine of the character described including a screen assembly, wiper mechanism for clearing the screens of lodged particles of material, comprising Wiper members positioned beneath the screens, a frame assembly at each side of the screen assembly and supporting the wipers, means for oscillating the wipers to cause them to tap the undersides of the screens, rollers supported alongside the screen assembly, the said frame assemblies being supported on said rollers for reciprocating movements with respect to the screens, and means for moving the frame assemblies on the rollers to move the Wipers back and forth beneath the screens.

3. In a material sizing machine of the character described including a screen assembly, Wiper mechanism for clearing the screens of lodged particles of material, comprising wiper members positioned beneath the screens, a frame assembly at each side of the screen assembly and supporting the wipers, means for oscillating the wipers to cause them to tap the undersides of the screens, rollers sup-ported alongside the screen assembly, the said frame assemblies being supported on said rollers for reciprocating movements with respect to the screens, means for moving the frame assemblies on the rollers to move the wipers back and forth beneath the screens, and the said rollers being supported for independent and simultaneous up and down adjustments with respect to the screen assembly for adjusting the Wiper members with respect to the screen.

4. In a material sizing machine of the character described including a screen assembly, wiper mechanism for clearing the screens of lodged particles of material, comprising wiper members positioned beneath the screens, a frame assembly positioned at each side of the screen assembly and operatively supporting the Wipers, support members adjacent said frame assemblies, rollers on said support members and engaging and su-pporting the frame assemblies for reciprocating movements to carry theY wipers back and forth beneath the screens, means for reciprocating said frame assemblies, and means for both selectively and simultaneously vertically adjusting said support members to adjust the wipers with respect to the screens in two angularly related planes.

WILLIAM J. PETERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 142,023 Hunter et al. Aug. 19, 1873 190,572 Fulton May 8, 1877 403,088 Burnap May 14, 1889 427,774 Lister May 13, 1890 1,122,765 Kime Dec. 29, 1914 1,202,378 Fraser Oct. 24, 1916 1,234,299 Dibert July 24, 1917 1,247,427 Liggett Nov. 20, 1917 1,286,389 Mullen Dec. 3, 1918 2,051,085 Ilseman Aug. 18, 1936