US2506628A

US2506628A - Adjustable sheet separator mechanism

Info

Publication number: US2506628A
Application number: US32768A
Authority: US
Inventors: Elmer W Belluche; Frank R Belluche
Original assignee: CHRISTENSEN MACHINE CO
Current assignee: CHRISTENSEN MACHINE Co
Priority date: 1948-06-14
Filing date: 1948-06-14
Publication date: 1950-05-09
Anticipated expiration: 1967-05-09

Description

May 9, 1950 E. w. BELLUCHE ET AL. I 2,506,628

ADJUSTABLE SHEET SEPARATOR MECHANISM I Filed June 14, 1948 5 Sheets-Sheet 1 12a. 1. A I 13. Z

"9 FIT FIXED ELEVATION 8 FIT FIXED ELEVATION PRESENT INVENTION FOR MANUAL ncTum'lou May 9, 1950 E. w. BELLUCHE ET AL 2,505,628.

ADJUSTABLE SHEET SEPARATOR MECHANISM Filed June 14, 1948 5 Sheets-Sheet 2 awemkm Elmer" WBPZ/L/Uhg Frank REE/[why & 3M! 2&5 8N

May 9, 1950 E. w. BELLUCHE ET AL 2,

ADJUSTABLE SHEET SEPARATOR MECHANISM Filed June 14, 1948 3 Sheets-Sheet 3 bwmk'ow Elma? PEEP/lush? frank EEYPl/L/U/YE Patented May 9, 1950 ADJUSTABLE. SHEET SEPARAT'OR MECHANISM Elmer: W; Be1iuche. and FranlLzRs. BellucheaRaicine; Wisaiassignors to The: GltristcnsenuMachine, Gomp any' Racine, Wis., a corporation of Wisconsin ApplicationJunel'i, 1948;" Serial-No; 3%768' 1% Claims. 1

This invention relates. to feederszfor printing;

machines, and refers more particularlyto: the: sheet separator mechanism. of such; feeders, by: which: the topmost sheet: of a pile of: sheets is separated from the pile and advanced towardfeed oflmechanismat the fronts of; the pile.

In practice, a pileof papersheets tosbe. fedto: a printing machine-or thelike by the feeder' is; supportedon a platform: with the front. edge of;

the pile adjacent:t'o the feed off mechanism of the-sfeeder: and with the topmost: sheet of:' the pile in predetermined eleyational relationship with; respect to th-e feed oif mechanism.

Since the platformuponwhich the pile of sheets rests is automatically elevated periodically'dur ing operationofthe -feeder; no difiiculty has-'- been experienced in maintainingthe pile of sheets in: proper relationship to" the feed off mechanism.

However; considerable difiicul'ty is experienced in properly locating the top..rearof the pile withv respect-to the=separator:mechanism to enable the separator instrumentalities to functionproperly in the separation of the: topmost sheet from the pile. Differences in: elevation between the top' of the pile at the front and back thereof is most: noticeable when. the. sheets: supported on the platform have been printed one' or moretimes and-'- especially when the printing largelysconfined' to' areas ofthe sheets'locat'ed'nearthe front 01': back of the pile; Underthese-circumstances, the pile tends to bulge upwardly at the'inked or printed portions ofthe sheetsdue-to the: many super imposed thicknesses of ink; while unpr-inted'portionstendto lie perfectly fiat.

Assuming a, condition where previously printed sheets are supported' on the platform ofthe feeder and where the printing was-confined chieflyto the front'portionsoithe sheets,- itwi1l' be'apparent that although the platform may be adjusted to bring thefront'of the pile tothe proper elevation with respect t'o'the feed off mechanism; the rear of the-pile will be at an elevation substan tially'lowerthan that of'the frontof thepile-and consequently will not be in proper elevationalrelationship with respectto the sheet separator. mechanism which operates-on the rear portion of the-pile;

Inorder tcompensate for the differences in height between the front and rear portions ofthe pile it was necessary previously to insert wedges and/orspacers-between the 'sheets of the pile at a number-oflocations in-the-pile-to-bring the; rear thereof to a properelevation permitting eflicient use of the separating -instrum ental flies".-

The use of wedges and. spacers, of course, is: objectionable, sinceiitris; a". relatively: difiicult and time consuming: under-taking to insert spacers: or drive wedgesxint'oi place. inthe pileand often: causesdamageito mam'ofithe-sheets in the pile Moreover, a. wedgedeup pile of" sheets must; be.- givenperiodic attention-- forrthe removal :of wedges. rendereddnoperatiye astheheightzof the piledecreases-during: operation :1 of t the feeden. Usuallm, s-uchremovaLof wedges and spacers requiresstom page ofithe; feedercandithe ipress supp ied117 1 5.-

With this objectionin. mind ittisuan object of this invention to provide; sheet feeders: with, a separating: unit; readilyadjustable up and down relative to; the feed;- ofij mechanism to: enable proper: elevationalz positioning: of; the separating mechanism withirespectgv toithe topmost sheet. of the pile: atthezrear thereof regardless of ine q ualitiesiinuthez height; of the: pile: as: between its front; andreartnortions; 1,

Another; object 1 of: this; invention resides in the; provision of separator: mechanism: of the, characten described which isrnot. only adjustable .verticallyrrelative; to the feed ofilimechanism'oi, the feeder,- hutzwhich is: providedwith improvedimeans for efiectingalateral adjustment of: theseparator, instrumentalities.

Still another; obj ectmf this inVention; resides. in theaprcvision of: improved means; for automat=- ically elevatingihe; platformnpomwhich; the pile of:' sheets; is: supported: to. maintain the topmost; sheet-:of the .pile at'a predetermined;.elevationbest suitediforieedingsofthesheets. a

With the above and other objectsvin'view, .which will appearas the': description proceeds, this ine vention: resides: in the: novel construction; combie nationa'l'id arrangementof parts substantially as hereinafter described; and; more particularly dc.- fiiiediby the appendedsclaims;.it; being understood that suchzchangesin'the precise embodimentioi' the hereim disclosedinvention may be made. as come within the scope of the claims;v v The accompanying drawings illustrate one complete example ofthephysical embodiment of the invention' constructed according to the a best mode scr far devised-for the practical application of the principle thereofi'. and in which: Figure 1 is-adiagrammaticside-elevational view showing the heightrelationshi-ps-betweenthe separator and feed off" mechanisms of a sheet feeder with respect to thetopmost'sheetof a pile having greater-"height at the front" edge of the pilethan at the backed'ge ofthe pile;

Figure 2" is"a similar" diagrammatic-view illustrating the" steps that were ta'ken' in the past to 3 bring the top of the pile of sheets to a uniform height at its front and back edges;

Figure 3 is a diagrammatic view illustratin the manner in which inequalities in height at the front and back edges of the pile are compensated for by the adjustable separator mechanism of this invention;

Figure 4 is more or less diagrammatic perspective view of a portion of the separator unit illustrating the manner in which it is adjustable, both vertically and laterally;

Figures 5 and 6 are side elevational views of the separator mechanism illustrating the same in two difierent positions of vertical adjustment;

and

Figure 7 is a diagrammatic view similar to Figure 3 but illustrating the manner in which the platform for the pile of sheets is automatically elevated as the height of the pile diminishes to maintain the top of the pile at a predetermined elevation.

Referring now more particularly to the accompanying drawings and particularly to the diagrams of Figures 1 and 2 illustrating conventional practice, the numeral 5 designates the platform of a pile type sheet feeder. The platform is adapted to support a pile of paper sheets 6 'at'the rear of the feeder and at an elevation such as to bring the topmost sheet of the pile substantially tangentto the upper cylindrical surface of a feed roll 1 forming part of the feed off mechanism generally designated 8 located at the front edge of the pile.

Sheet separator mechanism generally designated i is carried by the feeder to act upon the topmost sheet of the pile at the rear thereof, and the separator mechanism includes the usual combing wheels, and suckers and blowers not shown, which operate upon the rear portion of the topmost sheet of the pile to separate the same from the pile and effect advance of such sheet to the feed off mechanism 8.

When the forward edge of the topmost sheet is advanced over the feed roll I a drop roll II is brought down onto the sheet so that rotation of the feed roll 1 propels the sheet forwardly off 7 the pile. In all sheet feeders of the type herein concerned it is customary to maintain the platform at a height so that the elevation of the front of the pile of sheets at all times bears a predetermined relationship to the feed off mechfor feeding the topmost sheet of the pile into the feed off mechanism 8 automatically disposes the rear portion of the pile at the proper elevae tion for operation of the separator instrumentalities thereon. V

In the past the separating unitof sheet feeders of the type herein concerned has been supported from the feeder at a fixedelevation relative to the feed off mechanism 8, and while this arrangement proved satisfactory for the feeding of clean or unprinted sheets, or for the feeding of clean sheets to multicolor presses, it gave rise to serious objections in the event the feeder was used with single color presses requiring the sheetsto be fed through the press a number of times for the printing of different colors thereon.

In cases where the printing was confined I chiefly to the front portions of the sheets a pile 4 of such printed sheets to be run through the press another time invariably was higher at its front edge than at its back edge, as seen in Figure 1 of the drawings, and the separating instrumentalities operable upon the rear portions of the sheets of the pile were sometimes incapable of effecting their proper functions because of the insufficient elevation of the rear of the pile.

In practice, therefore, it has been necessary to insert wedges !2 into the rear and side edges of the pile at dififerent elevations to lift the rear portion of the pile up to the elevation at which the separating instrumentalities properly engaged the topmost sheet of the pile for the performance of their functions.

In the present invention the separator unit [5 is readily adjustable vertically relative to the feed off mechanism 8 to enable proper positioning of the separating instrumentalities of the unit with respect to the sheets at the rear of the pile despite inequalities in the height of the pile at the front and rear portions thereof. Hence, as

seen in Figure 3, which illustrates a case where the topmost sheet of the pile is at a lower elevation at the rear of the pile than at the front thereof, the separating mechanism may be lowered as a unit to the elevation required for proper engagement of the separating instrumentalities with the topmost sheet of the pile.

The separating unit comprises a pair of sepa-' rating heads l6 and I! upon which the usual separating instrumentalities including combing wheels, and suckers and blowers not shown, are mounted.

Each head comprises an inner and outer mechanism housing l8 and [9, respectively, joined together in spaced apart relationship and each mounted for sliding motion lengthwise along a pair of adjacent supporting shafts 2B and 2| forming part of a carriage 22 for'the separator mechanism.

The carriage 22 as stated comprises the pair of shafts 2i and 2|, and these shafts have their opposite end. portions received in end frames 23 so as to be held in spaced apart parallel relation-- ship by the and frames. Although the

shafts

20 and 2| hold the end frames spaced apart a distance substantially corresponding to the spacing of the side frames 25 of the feeder which extend horizontally rearwardly over the pile of sheets to;

be fed, the foremost shaft 2! is journalled for rotation in suitable hearings in the end frames 23 While the rearmost shaft 20 is fixed against turning. V

The opposite ends of the shafts project from the outer sides of the end frames and have

similar levers

26 and 21, respectively, mounted thereon. The levers 26 are free to rock upon the projecting ends of the fixed shaft 20 While the levers 27 are fixed on the shaft 2| to rotate or oscillate therewith. The levers have their arms extending downwardly and the lower ends of the arms of each pair of levers are joined-by a link 28. The points of connection between the links and the lever arms are spaced the same distance from the axis of the levers in each case, and the links hold the levers in parallel relationship so as to produce parallelogram linkage at each end of the carriage.

The entire separator unit is supported from the supporting or side frames 25 of the feeder by means of the parallelogram linkage described, in-

asmuch as the links 28 are seated upon the toplensthw-isathereofi. Hence, swinging; ofe thelimc-a age to. bring; the: levers. toward a. vertical position). fromeitliensidebf: vertical: effects bodily-lifting. of: the; separaton' unit; relative: to the: supporting' frames 25. and: consequently relativelyto'the feed. off. mechanism. 8; to; enable; accurate positioning: of the separating instrumental'ities; (not shown") withrelation to; the topmost. sheet: at; the rear: of; theapilez.

Adjustmentzof 'theheightoi: the separating. unit.- relativeto the pile: is efiected; by; means: of: a. hand: wheel) 3 BifiXedi omthereanen-d; of; an. adjusting screw- 34. This; adjusting screw" has: its; rear. end: portion: journalled ire. a; bearing: 32 carried? by; a. bracket; 335 connected; across. the supporting; shah/sates and 2:! between: the; separaton heads It; and lfie, and? the forward end oftthea adjusting screwis threaded; into: a. not; pivotally. carried.

by; the upstanding armof a. lever 35TfiXBII1lOnithE rotatable shaft 2L.

Inasmuch asv the adiusting: screw 3b is. held againstaxial': sliding motion by the-bearing. 3%, it: will. be apparent thati rotationof' the hand; wheel 30 impartsosci'llatory motion tothe shaftZ I' in a. direction. depending: upon. the direction of rota-- tion of the-hand wheel. Theoscillation thus fin.- partedtatheshaft-Z I ofcourse; issiinultaneously transmitted bathe parallelogram linkage on: the opposite ends of thesupporting shafts to. efiect: either'raising or. lowering offthe separator unit.

Unand down: adjustment; of the separator unit is constrained to a vertical translating motion by the transverse pinion shaft 3 1 which providesfor longitudinal adiustment of 'the separator unit.

The shaft 37'' is more or less conventional in most feedersand has pinion-s 3h mounted on its opposite'ends (only one of-- which is-shown-D meshing with fixed" horizontal racks 39supported from. the opposite supporting'fra-mes 25E In-the-present case theshaft 31 isreceived in vertical slots 40 opening to the-undersides ofthe-end frames 23"of the separator unit so-that rotationof' the shaft in one direction or the other propels the separator-unit'bacl'rwardly or-forwardly of the f'eeden to enable adjustment'ofthe separator unit at the proper point with relation to the rear-edge of the sheets on th'epil'ei Hence, it Will be apparent that this shaft 31 which is embraced by the-sides of the slots 40 in theand frames 23 guides the separator unit for 1 vertical up and down motion in response to -swinging ofthe' parallelogram linkage in one direction or theother.

Transverse adjustment of each of the separatorheads H3 and I'l is effected by rotation: of? a hand Wheel 42 fixedto a nut 43' encirclingthe shaft wand having internal screw threadscoopcrating with screw-threads on the" exterior-oi theshaft' 2B.

The nut ioreach separator head has its opposite ends rotatablyreceived in suitable bearings 45 carried by the mechanism housings of the heads, with each nut spanning'thespace between its-housings as shown best in Figure 4. Thebearings 55 in the separator heads preclude endwise motion of the nut relative: tothe heads so-that rotation of each ofthenutsbyzits hand wheel causes: its mechanism head to be drawn either inwardly or outwardly laterally of theseparator unit.

Once the platform for supporting the pileof' sheets has been adjusted to bring the-top of the pile to the proper elevation withrelation tothe feed ofif mechanismv 8; the; height; 015' the; pile. is automatically maintained by means:. which: peamedically lifts the platform: as. sheets; areied off: the pile. The. pile. elevating meansr comprises: air.- electric motor preferably drivingly -connectem through. a suitable gear; reduction, notv shown, with the chains; 5.] byWhiGhlth;p1atffi1'-m 51iS susa pended. These; chains; depend from. suitable; sprockets. in. the conventional mannenand. since; thezmannerrof: connecting. the: platform witlr the: motor-iormsrno part of 't-hisinvention it: is sufiia cient. tozpoint'. out that the motor is. of there-- versible 'type'so: thatoperationa thereof: in one.- die. nection efiects lifting of: thexpl'atform 5. while ops. oration; in the oppositedirection eiiectslowering: of the: platform.

As the height of the pile of sheets. diminishes during successive". feeding of the sheets by the feeder,- the electric motor isput into operation periodically for brief intervals-of time tobringthepile tothexproperelevation for the feed ofi 'oper ationa This: is accomplished in. the present in vention bymeans-ofa feeleri! carried by a pair. of vertically spaced levers 53 and 54' for endwiseup and down motion toward and from the t0p of= thelpil'e of: sheets at: the rear of the pile.

The feeler may be carriedby either one'of the supportingheads but in the present case is'shown connected with the innermostmechanism'housing I18 of the head t6.- The levers- 53- and 54 are pivotally. supported on'the" inner side of the housing it for-rocking motion: about transverse axes spaced one above the other and with their arms 55 and 56-, respectively; which connect with the feeler extending substantially horizontally rearwardly.

A cam 58-expcsed at'the-exterior eithe -housing" lit but driven by: mechanism within the-housing cooperates with a roller 59-onanother'ar-m Ell -oi the lowermost lever 7 5'4 toimpart rocking motion to both levers through the feeler and to cause the fecl'erto beliftedmpanddown;

Downward travel of the feeler; of course; is limited by: the engagement" ofits lower end with. the-pile of sheets, and as long: as thetopof the pile is at an el'evation best suited for efficient oporationof the feeding instrumenta lities; no eleva tional adjustment of the platform is: necessary; Upon decrease in the height of the-pile by--successive feeding of sheets therefrom, the feeler 52 de scend's farther-and farther each time it is-lowered by the camz58.

Sometime beforethe height of' the pile decreases an extent interfering with efficient operation of the feeding-instrumentalities, downward motion of the feeler-toward' the top of the pile effects closure of anormally open switch 62 mounted on the mechanism= housing IE- above an arm 63 on the leverit opposite thearmfii there-- of.

Theactuator 64: of the switchprojects downwardly to be engaged by the-arm 63 of lever 53. at this-timeto' effect closure of the switch by the up! ward movement oi the arm, and energization of the-electric moton 50 in a. direction toeffect elevvation of'the platform: 5;

Hence, wheneventhe-switch 5215 closed by the arm. 63: of? the. lever 53. inv consequence to descent of thefeeler beyond a: predetermined: level they motor iszsetzinto operationand thepl'atform begins to rise-slowly. tmreturnthe top-.of the pile t'o the proper height;

Sincethe feeler is.lifted;=up.-.and down periodically. it-will. be. seen that-the motor operates. in t'ermittently. to .lifttheplatform.toltheiproper e1evation; When the: height". ofi the: pile. back to. na'rmah the? ile: limits: downward descent: of the feeler and prevents the arm 63 of lever 53 from closing the switch, and further elevation of the platform ceases. i

The electrical connections between the switch and the motor are illustrated inFigure 7, and since these connections are deemed obvious no detailed explanation thereof is required. It is sufficient to note that a manually operable reversing switch 66 is provided. The switch 65 is in parallel with the switch 62 so that the platform may be raised or lowered at the will of the operator. The switch 68, of course, is provided mainly for the purpose of initially lifting the platform, and for lowering the platform after all the sheets have been fed therefrom.

/ Attention is directed to the fact that the feeler rod 52 is adjustably connected as at 61 to the

lever arms

55 and 55. Verticaladjusment of the feeler, however, is necessary only at the time of assembly of the separator unit, and when once adjusted, proper height spacing between the separator instrumentalities and the top of the pile is assured by reason of the fact the feeler is carried bodily with the separator unit during any vertical adjustment thereof.

In the present invention, the switch 62 is mounted upon a slide it which may be moved horizontally forwardly or rearwardly and locked in place upon the mechanism housing is by means of screws 'H. Consequently, the switch 62 is bodily adjustable toward and from the axis of the lever 53 so as to enable earlier or later actuation of the switch by the arm 63 of the lever 53.

If the switch is set substantially close to the axis of the lever it will initiate operation of the motor 53 at less frequent intervals than when the switch is set further away from the axis of the lever and toward the outer end of the arm 63 thereon.

From the foregoing description taken in connection with the accompanying drawings it will be readily apparent to those skilled in the art that the vertically adjustable separator unitof this invention materially facilitates setting up of the feeder to which it is attached; that exceedingly simple but efficient means is provided for automatically controlling the height of the pile of sheets acted upon by the separator instrumentalities; and that lateral adjustment of the separator instrumentalities is effected in a novel manner utilizing one of the transverse supporting elements of the separator unit. 7

What we claim as our invention is:

1. In a sheet feeder of the character described: a pair of spaced elevated supporting frames at the rear of the feeder to lie at opposite sides of a pile of sheets to be handled by the feeder; a sheet separator unit extending transversely across the rear of the feeder between said supporting frames and above the rear portion of said pile of sheets, said separator unit including a transverse supporting shaft, and separator instrumentalities operable upon the topmost sheet of the pile; means for supporting said separator unit from the supporting frames at any of a number of elevations with respect to said frames, comprising a lever fixed on each end of said transverse shaft, and a connection between each lever and its adjacent frame by which rocking motion of the supporting shaft in one direction effects bodily lifting of the separator unit; and means connected with said transverse shaft for imparting rocking motion thereto and for holding the shaft in any of a number of positions of rotation; 2. In a sheet feeder of the character described: a pair of spaced elevated supporting frames at the rear of the feeder to lie at opposite sides of a pile of sheets to be handled by the feeder; a separator unit including sheet separating instrumentalities operable upon the sheets of said pile; means supporting said separator unit from the supporting frames with the separator unit extending transversely across the rear of the feeder between said supporting frames and above the rear portion of the pile of sheets, said supporting means including 7 levers pivotally mounted on the separator unit adjacent to the supporting frames, and connections between said levers and the supporting frames adjacent thereto whereby swinging motion of the levers in one direction effects bodily elevation of the separator unit relative to said supporting frames; and means for imparting swinging motion 'to said levers and for holding the same in any desired position of angular adjustment.

3. In a sheet feeder of the character described: a pair of spaced elevated supportin frames at the rear of the feeder to lie at opposite sides of a pile of sheets to be handled by the feeder; a separator unit including a pair of end frames spaced apart a distance substantially corresponding to the spacing of the supporting frames and sheet separator instrumentalities connected with said end frames to be supported thereby and operable upon the sheets of said pile; means for supporting said separator unit from the supporting frames with the unit extending transversely across the rear of the feeder between said supporting frames and with each of said end frames adjacent to one of said supporting frames, said means including a pair of levers pivotally con-- nected with each of said end frames, and a link joining the ends of each pair of levers and slidably received on the adjacent supporting frame so that simultaneous swinging of each pair of levers in the same direction effects bodily lifting of the separator unit relative to the supporting frames; and means for imparting simultaneous swinging motion to saidlevers and for holding the same in any of a number of positions of angular adjustment.

4. The sheet feeder set forth in claim 3 further characterized by the provision of means for constraining up and down adjustment of the separator unit to substantially vertical translating motion.

7 5. In a sheet feeder of the character described a pair of spaced elevated supporting frames at the rear of the feeder to lie at opposite sides of a pile of sheets to be handled by the feeder; separator means operable upon the sheets of the pile; a carriage for said separator means com prising a pair of end frames spaced apart a distance substantially corresponding to the spacing between the supporting frames, and a pair of shafts connected between said end frames and joining the same together, said shafts being held by the end frames in spaced apart parallel relationship, one of said shafts being rotatably journalled in said end frames, and the other of said shafts being non-rotatably connected with said end frames; means mounting said separator means upon said shafts for sliding motion along the length thereof; a connection between said fixed shaft and the separator means for holding the separator means in any of a number of different positions along the length of'said shafts; and means supporting said separator unit from the supporting frames with the unit extending transversely across the rear of the feeder between said :supporting frames :and above the 1 rear ipor tion of the :pile (f :sheets, said ;means including parallelogramilinkage sconnec'ted .between :each :of said :shafts sand the supporting frame adjacent thereto to .enable' :elevational adjustment of the carriage :and the separator means thereon relative .to itheisupportingz frames.

6. :In a sheet'feederof the :character described: a pair of spaced elevated supporting frames at the :rear :of the :feeder atoilie "at opposite sides of a pile of sheets to be :handled tby the ifeeder; 2a sheetfseparatortunit'extending transversely across said supporting ifram'es, said separator unit :comprising a pair of supporting shafts, and end frames connected across said shafts at each end thereof to hold the same in spaced parallel relationship, with one'of said shafts journalled for rotation in said end frames and with the other of said shafts fixed against rotation, said separator unit vincluding separator means supported jointly by said shafts for sliding motion transversely of the feeder toward and from the opposite supporting frames thereof; a screw connection'be'tween said fixed shaft and the'separator mean-s providing for transverse adjustment of the separator means relative to the supporting frames of the feeder and to alpile of sheets between -said supporting frames; a lever fixed on each end of said rotatable shaft for rotation therewith; a lever loose on each end of said fixed shaft; said levers having arms substantially the same length; and a link pivotally connecting the arms of the levers at each end of said shafts, said links resting on the supporting frames so as to provide for up and down adjustment of the separator unit relative to the supporting frames upon swinging of the levers and links in one direction or the other; and means for imparting swinging motion to said levers and links and for holding the linkage in any of a number of desired positions of adjustment, said means comprising a bracket connected across said shafts, another lever fixed to said rotatable shaft, and a screw mounted on said bracket and threaded into a nut carried by said other lever for imparting rocking motion in opposite directions to said rotatable shaft through said other lever fixed thereon.

'7. In a sheet feeder, the combination of: an elevatable platform adapted to support a pile of paper sheets; means adjacent to the front edge of the pile for feeding off the topmost sheet of the pile, said means having a fixed elevation and requiring the top of the pile to be in a predetermined elevational relationship thereto; a separator unit including separating mechanism operable upon the rear edge portion of the pile of sheets and adapted to separate the topmost sheet from the pile and to effect advance of said topmost sheet to the feed off mechanism at the front of the pile; a feeler mounted on said separator unit for up and down motion and operable to feel for the top of the pile; means for raising the platform including a motor; a switch for conmeeting said motor with a source of E. M. F.; a connection between the feeler and said switch whereby downward motion of the feeler beyond a predetermined level at which the separating mechanism best operates upon the pile effects closure of the switch to initiate operation of the motor and raising of the platform; and means mounting the separator unit and the feeler for vertical adjustment in unison relative to the feed off means to enable initial positioning of the separator mechanism and the feeler in proper elevational relationship to the top of the pile at that it part thereof acted upon :by :the :feeler and the sepanating mechanism.

8. Aseparatoriunit for sheet feederscomprising: an elongated carriageadapted to be carried by the supporting structure of the feeder, said carriage including a screw shaft extending transversely across the rear :of the feeder; adjust-able means on said :screw shaft connected between the c'arriage and theasupporting structure of the feeder-for supporting th'eca'rriage from said supporting structure at any of :a number of levels above the top o'f-a mile of sheets beneath the carriage separatorzlmeans 1 operable upon the rear 0f a pile of sheets beneath the carriage; means including said screw shaft mounting the separator means on the-.'car1 i'age for lateral sliding motion lengthwise of 'said shaft; a tu'bular part encircling said screw shaft and having screw threads on its interior cooperating with the threads on the shaftso that rotation of said tubular part causes the same "to*be drawnalong the shaft in one direction or the'o'ther; and a connection 'between said tubular 'partand said separator'me'ans whereby the separator means is driven longitudinally along the screw shaft with :the tubular part to different positionscf latena l adjustment on the-carriage.

-9. In'ashee't feeder ofthe characterdescribed: spaced "elevated side frames *at the rear of the feeder; a separator unit including a separator head having instrumentalities operable upon the rear portion of a pile of sheets of paper to be handled by the feeder; means mounting said separator unit on said side frames for bodily up and down adjusting motion relative to said frames and to the top of a pile of sheets being handled by the feeder; and a feeler carried by said separator head for up and down motion relative thereto and adapted to feel for the top of a pile of sheets being handled by the feeder, said feeler being bodily movable with the separator unit to different positions of vertical adjustment thereof so as to at all times have a predetermined positional relation to the separator instrumentalities on said head.

10. In a sheet feeder of the character described: a pair of spaced elevated side frames at the rear of the feeder to lie at opposite sides of a pile of sheets to be handled by the feeder; a carriage extending transversely across the rear of the feeder between said frames and above said pile of sheets; separator instrumentalities mounted on said carriage and operable upon the topmost sheet of the pile; means for adjustably supporting said carriage from said side frames at any of a number of elevations with respect to said frames, including an element pivotally supported on said carriage adjacent to each of said frames, and connections between said elements and the frames adjacent thereto for translating pivotal motion of said elements in one direction into bodily elevation of the carriage relative to the side frames; an actuator connected with said elements for rocking the same in unison, said actuator including means for holding said elements in any of a number of positions of rotation.

1 1. In a sheet feeder of the character described: a pair of spaced elevated side frames at the rear of the feeder to lie at opposite sides of a pile of sheets to be handled by the feeder; a sheet separator unit extending transversely across the rear of the feeder between said side frames and above the rear portion of said pile of sheets, said separator unit including a rotatable supporting ll shaft extending transversely between said frames, and separator instrumentalities operable upon the topmost sheet of the pile; means for adjustably supporting said separator unit from the side frames at any of a number of elevations with respect to said frames, comprising connections between said shaft and each side frame operable to translate rotative motion of the shaft in one direction into bodily elevation of the separator unit relative to the side frames; and means connected with said transverse shaft .for imparting rocking motion thereto and for holding the shaft in any desired position of rota tion.

12. In a sheet feeder, the combination of: an elevatable platform adapted to support a pile of sheets; means adjacent to the front edge of the pile for feeding off the topmost sheet thereof; a separator unit including separating mechanism operable upon the pile of sheets and adapted to separate the topmost sheet from the pile and to effect advance of said topmost sheet to the feed off mechanism at the front of the pile; a feeler adapted to move up and down onto and ofi of the top of the pile; means for raising the platform including a motor; means mounting said feeler on the separator unit for said up and down motion of the feeler; an arm pivotally mounted on said separator unit and connected with the feeler 12 so as to swing back and forth on its pivot in consequence to up and down motion of the feeler; a. switch for controlling operationof said motor; means mounting said'switch on the separator unit adjacent to said arm so that the switch is REFERENCES CITED The following references are-of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,033,951 Sargent July 30, 1912 1,606,016- Christophel Nov. 9, 1926 2,074,330 Grover Mar. 23, 1937 2,160,491 Cernak May 30, 1939 2,183,077 Kast Dec. 12, 1939 2,233,895 Mestre Mar. 4, 1941