US 2759729 A
Description (OCR text may contain errors)
Aug. 2l, 1956 E. E. HEDLUN 2,759,729
SHEET FEEDING APPARATUS Filed March l2,- 1953 3 Sheets-Sheet l Aug. 2l, 1956 E, E. HEDLUN SHEET FEEDING APPARATUS E11/afan nes. 21k/lum /m MW Filed March l2, 1953 Aug. 21, 1956 E. E. HEDLUN 2,759,729
SHEET FEEDING APPARATUS I Filed MaICh 12, 1953 5 ShefllS-Shee'l 5 @XM1 Wwf/M .;-My invention yrelates 4`to -fafsheet feeding apparatus Whichiiscapable 'of feeding'fsheets. ofpapervonthe like from-.a stack to a discharge station inwa uniform manf=ner`and ata fast rate.
v"Thez--sheet feeding apparatus offmy invention -iszlca- -fpableof use .in numerous `apygalicationsyfand asrone 'ex .ample,1 theapparatus may be` usedl to .feedprintednlabels 'storta dischargestation at a `rate `,whichasynchroniZes with books or the like to which the labels areap'pliedisat fithe station.
.Thel apparatus of my inventionfisA capable offdeliver- -ingtsheets atanextremely fast rate, and inthercaserof Hlabelszof average size, the apparatus has operatedinta --satisfactory manner at the rate ofza thousand'sheetsa-per rrfminute. The rates usually encountered inv practicewwill fbe considerably lower, however, say upto 200 sheets-for labels'per minute, sincelthere are limitationson .the rate atwhich ythe sheets can be .handled atthe dischargeestation Sheet feeding apparatus of the type with which fmy inventionndeals uses a friction surfaced 4feed rollerllnit for the purpose of separating successivesinglesheets `from the-sheet stack. The separated sheets a-re-succes fsively conveyed in a forwardly'direction andeare disxcharged from the forward end of the apparatusfat anaccurately predetermined rate and at an accuratelynprede- "termined linear speed.
Due `to the frictional relationship '(betweenwthef-feed `roller'unity and'the sheets) which is-used to separate Yathesheets from the stack, a certain-amount oftsimposi- .tiveaction-is experienced. This impositive frictional. ac-
tion in prior apparatus often upsetsthe delicatertiming required-fand renders the apparatus temporarily inoperaetive. In "brief, if a first sheet is vslow to..estab1ish..an 'operative frictional relationship .with the Vfeed roller 'v-.unityand vthe next followingsheet is fast to establish-,such ..a-^re1ationship, the two sheets tend to bunchtlup. Similar `random -action with respect to the followingifsheets .tends to produce .non-uniform spacing 'between ysheets with ther result `that the mechanism at the 4discharge `end oflthe apparatus fails to ,deliver successivesheets .,atfthe ,predetermined,` continuous rate.
One object of -my invention, therefore isto-over- -come the aforesaid diiculty andprovidea sheetfeeding apparatus which is capable of delivering sheets at y.a..uniform predetermined rate, in a continuousjmanner.
Another object is to provide an apparatus of this character wherein the tendency-of the sheets to bunch up yor string out is eliminated.
.Still..another object of the invention is top'r'ovdefa sheet feeding'apparatus which can be depended onto operate properly at a'fast rate, such as one thousand Laverage, size labelsper minute.
.Another object is to provide in an apparatusff'this character a `system of l guides andconveyors which coi operate to insure that the sheets advance properly.
Generallyspealdng my invention is embodied ingapparatus which includes a" fee'dtray adapted'to" contain Patented Aug'. 21, 1956 vfthe feed'tray Where it engages the first sheet in the stack Thefeedrollerunit rotates at a rate which advarices-@sheet .aty a linear speed which is substanttially thigher-than'the linear speed of a sheet at the discharge end of the apparatus.
rthe feed rollerv'unit advances the sheet to ay rst conveyoresystem-whichfunctions to advance the sheet lat substantially.the same linearspeed as .that provided by -the-feed roller unit. The effective distance or spacing 4between ythe 'feed roller unit and the rst .conveyor sys- -tem is substantially less'than the lengthl of one of the sheets being handled.
The firstlconveyor system yadvances the sheet to a rest. position `"where it can be acted onv bya1 second'con* veyor\ systern, the effective ydistance between '.the two conveyor systems being substantially fequal to :a sheet l` length. t'lihef second conveyor system functions to Vdisfcharge-:thefsheets at` the desired predetermined rate, and
'Y-itmalsowfunctions to advance the sheetsv at the desired'predetermined linear speed. This linearV speed, however, is
".-some`what less than the sheet speed providedby the aforesaid Tfeediroller unit andtiirst.conveyorlsystenL Thellfeed roller funit, which functions tov advance a I sheet-f atea linear speed-:greater than the`=predetermined .discharge linearspeed, is driven '-.throu'gha clutch which '-ris :responsiveftof a clutch` actuator located between -the first and second.' conveyor systems. v"lf-he clutch actuator,
-whichdin 'practice may be afwirer feeler, a yphoto-electric -.'-device,for the like, is energized by the forward end of a *sheet andthe'bodyof thesheet as fthe sheettravels and restsfbetweenfthefirst and second conveyor systems.
fAssu'rnir'iglthe'A clutch normally is inl engaged vcondi- Atio`nl-v`/iththe feed roller unit operating, asheet is adfvancd-lfat a"v fast linear speed bythe feed 'roller unit -to the rst conveyor system which" in turn advancesthe f'sh'eet fat'thef'same' fast linear speed to the rest position `where-it can be acted on by thesecond conveyor system. t'As'i-thelsheet travelsV between the "frstandsecond conveyor systems, 'the'forwar'd sheet end energizes 'the aforefth'at the sheet clears the clutch actuator, thereby percessiVe-*sheets are'thus positioned,v thesecond conveyor vmitting the clutch to become reengaged and the feed `roller'ur'lit yto advance Ythenext following'sheet.
v'This arrangement of super-speedfeed roller, superrspeedrstconveyor system, feed rollerclutch and sheet "responsive clutch actuator 'insures the presence at all ltimes'of a sheet in proper positionl to be acted on'by the second or discharge conveyor system. VWhen the sucsystem is able at all times to discharge sheets at the predetermined rate and at the predetermined linear speed. JHowever, if `this positioning is not assured, :as in the case of prior apparatus of'this character, `it will'be seen that l"tlief second ordischarge conveyor system is unable to so "function in a-'reliable manner.
"Other objects, advantages and details of Vmy invention will become apparent as thedescription proceeds, referencetbeing had to the accompanying drawings which illusy'trate oneform of the invention. It is to be understood thatthe :description and drawings -are illustrative only, and are not to be'taken as limiting the invention except insofar as it is limited by the claims.
'A'In the' drawings:
l EFig lisa side elevational'view, partly'in section,of2a 'sheet feeding" apparatus -er'nbodying 'my invention;
Fig. 2 is a sectional view on line 2-2 of Fig. l;
Fig. 3 is a sectional view on line 3-3 lof Fig. 1, and
Fig. 4 is an enlarged sectional view illustrating certain details of the invention.
Referring to the drawings, a sheet feeding apparatus embodying my invention includes a suitable supporting framework generally designated 5. Fo-r convenience, the portion of the framework at which the sheets start their travel is referred to as the rear of the framework, and the direction travelled by the sheets along the framework is referred to as the forwardly direction.
A feed tray generally designated 6 is mounted at the rear of framework S. In the form of the invention shown, the axis of tray 6 is inclined at an angle to the direction travelled by the sheets through the apparatus, as shown in Fig. l. The illustrated feed tray 6 has a bottom supporting structure 7 and sides 8 and 9. One or both of the sides may be adjustable transversely of the bottom supporting structure so that the sheets may be centered with respect to the apparatus and so that sheets of different sizes may be accommodated. Bottom supporting structure 7 of the feed tray is mounted between its ends on a strut 10 which extends from framework 5. The forward and lower end of bottom supporting structure 7 is aixed to framework 5 in a suitable manner such as is shown at 11.
A sheet stack 13 is shown in operating position in tray 6, the individual sheets being disposed vertically with this feed tray arrangement. The forward end of the feed tray carries a pair of upstanding struts 15 and 16 (Fig. 2) which extend vertically beyond the top of stack 13 at that point. A shaft 17 interconnects the upper ends of struts 15 and 16 and carries intermediate its ends a pivoted knife 18. As shown, knife 18 bears against the upper forward corner of the stack to prevent the sheets from falling forward and to exert downward pressure on the first one or two sheets of the stack. This downward pressure assists in bringing the first sheet of the stack into operative relation with the presently to be described feed roller unit. With wider sheets it is sometimes desirable to use more than one knife 18.
At the forward end of the feed tray is disposed a feed roller unit, for convenience hereinafter called feed roller 20, which is rigidly mounted on a shaft 21. The latter is supported in bearings 22 (Fig. 2) carried on framework 5. Feed roller 20, which extends transversely of framework 5, may comprise one roller, or, more likely, it compries two or more individual rollers spaced along a portion yof the shaft. The mechanism will be referred to in the singular for convenience.
Feed roller 2t) has a cylindrical surface which in the form illustrated (Fig. 2) comprises rubber and steel laminations, rubber fo-r friction and steel for wear. Looking at Fig. l, feed roller is adapted to rotate in clockwise direction (arrow). As will be seen in the drawing, top sheet 23 of the stack engages the surface of roller 20 more or less tangentially. The friction developed at the roller surface causes the roller to peel sheet 23 from the stack and to move it around the roller in the direction permitted by an arcuate guide 24 positioned below the roller.
Referring back to feed tray 6, the bottom supporting structure 7' thereof carries a spacer plate 23 on which is superimposed a bottom plate 26 which is adjustable longitudinally of the tray. A suitable micrometer arrangement 27 may be provided to obtain accurate longitudinal positioning of bottom plate 26. Such positioning is necessary in order to provide proper clearance between the upper forward edge 28 (Figs. l and 4) of the plate and feed roller 20. This clearance, of course, must be adjusted depending on the thickness of the sheets fed in a particular operation, and it should just exceed the sheet thickness.
It is highly important that upper forward edge 28 of plate 26 be truly parallel with the surface of feed roller 20, and it is also important that this edge have a sharp corner. Since this corner is subject to wear with eX- tended use of the apparatus, it is desirable to make both ends of bottom plate 26 of durable metal such as hardened steel, and to grind all four end corners accurately. Thus, by inverting and reversing bottom plate 26, four edges with sharp corners are available before regrinding or replacement is necessary.
As mentioned, sheets from stack 13 are successively advanced by feed roller 20 in a forwardly direction. The sheets are fed by feed roller 20 to a rst conveyor system generally designated 30.
First conveyor system 30 includes a transversely extending first conveyor roller 31 carried on a shaft 32 which is suitably journalled in bearings carried on framework 5. In the form of the invention shown, conveyor roller 31 is located below the travel path of the sheets.
Cooperating with first conveyor roller 31 and positioned thereabove is an idler roller 33 which is mounted on a shaft 34 suitably journalled in bearings (not shown) at its ends. These bearings are slidably mounted for up and down movement in a well known manner, and they are biased by springs 35 in a downward direction. Thus, idler roller 33 makes a yielding engagement with first conveyor roller 31. The latter is driven in a counterclockwise direction, looking at Fig. l, and the two rollers 31 and 33 cooperate to advance a sheet in the forwardly direction.
The effective spacing between feed roller 20 and first conveyor roller 32, normally measured by the distance between the centers of the respective rollers, is substantially less than the length of the sheet used in a particular feeding operation. So that the apparatus may accommodate sheets of different lengths at different times, suitable means are provided to vary this spacing. In the form of the invention shown, the sub-framework structure 36 which carries first conveyor system 30 is movable longitudinally of the apparatus in an adjustable manner.
First conveyor roller 31 has circumferential grooves 38 in its surface, and disposed in each of these grooves is a portion of the horizontally extending lower guide 40. In general, lower guides 40 extend below the sheet path from the vicinity of the exit point of feed roller 20 to the presently to be described second conveyor system.
Idler roller 33 likewise has circumferential grooves 41 in its surface which receive portions of upper stationary guides 42. The rear end of guides 42 preferably are curved as shown at 43 to provide a throat. The forward ends of upper guides 42 terminate short of the following described second conveyor system.
The second conveyor system, generally designated 45, includes a second conveyor roller 4.6, disposed above the sheet path and carried on a shaft 47 which is journalled in bearings 48 and 43a (Fig. 3). The latter is carried by an upright frame member 49 which is adjustable longitudinally of framework 5. Since the effective spacing between the first and Second conveyor systems must be substantially equal to the length of a sheet, this adjustment makes it possible to feed sheets of different lengths with the apparatus. Bearing 48 is carried by a downwardly extending frame member 9a which is structurally connected to and parallel with upright frame member 49 (Fig. 3).
Second conveyor roller 46 (Fig. l) has an irregular surface. A major segment of the roller has a radius 50 while a minor segment has an increased radius 51. The segmental surface of increased radius constitutes a cam surface 52, the only surface of roller 46 which comes in contact with and is effective to advance the sheets.
Second conveyor system 45 also includes a roller 55 mounted below the sheet path in position to be engaged by the cam surface 52 of roller 46. Roller 55 is carried on a shaft 56 suitably journalled in bearings 57 and 57a (Fig. 3), respectively, carried by upright frame member 49 and downwardly extending frame member 49a. The
adsense surface of roller 55 has circumferential grooves 58 to accommodate portions of the previously vmentidriedlower guides 40.
In the form of the invention shown, roller 55, in addition to cooperating with. cam surface 52 of 'roller 46 to advance the sheets, .has another function, namely that of applying glue to the bottom surface olf the conveyed sheets. Therefore, the lower .partV of roller 55 extends into a glue receptacle 59 in which glue yis tn'aintained at a level above the lower portion of the roller.
Lower and upper guides 6i) and 6l (Fig. l) may be positionedl forwardly of second conveyor system 45 'to channel the sheetstoH the dischargefstation (not shown) where, for example, they are glued to passing books or catalogs. These guides form the forward end of the herein described .sheet feeding apparatus.
Feed roller 20 and the two conveyor systems 30 and 45 are driven in any suitable manner from a mechanical power source. One suitable form of drive system wil now be described. The feature of importance to the invention in connection with the drive system is` that feed roller 2t) and iirst conveyor system 3i) are driven at a speed so that they advance the sheets' at the same linear speed, and that second conveyor system 45 is driven so as to advance and discharge the sheets at a somewhat lower linear speed. This latter speed is' sometimes referred to herein as the predetermined linear speed.
Referring to Fig. l, a continuously rotating drive shaft 65 is journalled in a bearing 66 carried on the framework. Shaft 65 is driven from amotor or other suitable source (not shown). A sprocket 67 is rigidly carried on shaft 65.
A shaft 70 (Figs. 1 and 3) is journalled in bearings 71 and 7la carried near the upper ends of frame members 49 and 49a, and a sprocket 72 is rigidly carried on the shaft. A chain 73 drivingl'y relates sprockets 67 and 72 so that shaft 7d rotates with drive shaft 65.
Shaft 70 also carries a gear 74 (Figs. l and 3) which meshes with a gear 75 carried on previously mentioned shaft 47. The latter, which carries second conveyor roller 46, thus is driven by the motor or power source. The portion of the drive system described so far comprises a rst drive means which drives second conveyor system 45 in such a manner that it discharges sheets at predetermined linear speed. it will be remembered that a sheet is discharged from this conveyor system only when cam surface 52 of roller 46 is rotated into engage ment with a sheet.
Shaft 47 of second conveyor system 45 also carries a cam roller 76 (Fig. 3) which engages a friction surfaced roller 77' carried on shaft 56. Since the effective shape of caml roller 76 corresponds with that of second conveyor roller 46, shaft 56 is driven in such a manner as to rotate roller 55 when the latter is' engaged by cam surface 52 of roller 46.
The driving means for iirst conveyor system 30 includes a sprocket 7S (Fig. l) carried on shaft 32. This sprocket is engaged by the chain 73 which also engages sprockets 67 and 72. The radii of sprockets4 72 and 7S are selected so that first conveyor roller 31 rotates at a speed which imparts to a sheet a linear speed which is substantially higher than the said predetermined linear speed provided by second conveyor system 45 at the discharge end of the apparatus.
A sprocket SS (Figs. l and 3) also is carried on shaft' 47, and this sprocket is connected by a chain 86 to a sprocket SS (Figs. l and 2) which is connected to driving element 89 (Fig. 2) of a clutch diagrammatically shown at in the form of the invention shown, sprocket 38 and driving element 89 are j ournalled on shaft 21 which also carries feed roller Ztl. Thus, shaft 47, sprocket 85, sprocket 88, chain Se and clutch- 9@ f comprise a third drive means which functions, when the clutch is engaged, to drive feed roller 20 in such a manner' that it advances a sheet at the same linear speed as that provided by the second drive means, a linear speed which is somewhat faster than theV said predetermined linear speed.
Clutch 90 has a driven element 91 which is keyed to shaft 21 as shown in Fig. 2. When the clutch is engaged, shaft 21 and its associated feed roller 20 are driven from sprocket 8S. Conversely, when the clutch is disengaged, no driving force is applied to shaft 21, and feed roller 20 stops. Thus no sheet is advanced by feed roller 20 when clutch 90 is disengaged.
Clutch 90 may be of any suitable type such as' friction or magnetic. Clutch operation is controlled by a presently to be described clutch actuator which is located between the first and second conveyor systems and which is energized by the presence or absence of a sheet in the range of the actuator.
A clutch actuator, generally designated (Fig. l), isV
located between first conveyor system 30 and second conveyor system 45. Any suitable type of actuator maybe used so long as it is operable in response to the presence or absence of a sheet in the effective range of the actuator. For example, a photo-electn'c device may be used with a sheet being effective to interrupt a light beam. In the form of the invention here shown, actuator 95 employs a wire feeler 96 having a free end which extends across the path of sheet travel. The other end of feeler 96 is carried by the actuating element of a microswitch 97.
Microswitch 97 is connected in a circuit (not shown) with electrical components which function to operate clutch 90, that is, to engage and disengage the clutch according to whether microswitch 97 is open or closed. If clutch 90 is a mechanical friction clutch, the circuit including microswitch 97 normally would have a solenoid to 'pro-A vide the mechanical movement necessary to engage and disengage the clutch in response to switch operation. If a magnetic type clutch were used, the circuit of microswitch 97 normally would include a relay switch which in turn is connected in circuit with the` magnetic clutch and the source of power for energizing the clutch.
lt will be understood that the precise character of clutch actuator 95, clutch 90 and the electrical and/or mechanical connections therebetween are not limitations on the scope of the present invention. it is only necessary to provide a suitable clutch in the feed roller drive system and a suitable clutch actuator to function in response to the presence or absence of a sheet in the region between the first and second conveyors.
In operation, the clutch actuator is effective to disengage clutch 90 when a sheet approaches its position of rest at the rear of second conveyor' system 45, and it is effectiveto engage the clutch when a sheet is picked up and advanced by the second conveyor system.
The operation of my sheet feeding apparatus is initiated by rst loading hopper 6 with a stack 13 of sheets or labels; To insure proper relation between the top sheet of the stack with feed roller 20 a weight99 (Fig. l), or the like, is provided to bear against the rear of the stack. Micrometer 27 is suitably adjusted to provide proper clearance between the corner 28 of bottom plate 26 and feed roller 2t1,.as previously described.
With the various drive systems operating, feed roller 20 establishes a frictional relation with the top sheet 23 of the stack and advances it between roller 20 and arcuate guide 24. Where the sheets are of extremely thin stock,
guide 24 is provided with an auxiliary arcuate guide 100vv which functions to guide the sheet from corner 28' to guide 24. Auxiliary guide 100 may be carried by guide 24' or it may be carried by the spacer plate 25 disposed between bottom plate 26 and bottom supporting srtucture 7 of the tray, as shown in Figs. land 4.
Feed roller 20, as previously mentioned, advances sheet 23 at a linear speed which is substantially faster thanI the predetermined linear speed of sheets at thefdischargeend of the apparatus. Before sheet 23 breaks its engagement with feed roller 20, its forward end engages rst conveyor system 30 which functions to advance the sheet at the same linear speed as that provided by feed roller 20. Sheet 23 then is advanced by first conveyor system 30 to a position of at least momentary rest at the rear of second conveyor system 45. This rest position is illustrated by the position of sheet 101 in Fig. 1. From here the sheet is engaged by cam surface 52 of the second conveyor system and discharged through the guides 6i) and 61.
The rest position mentioned above is provided for, in the illustrated form of the invention, by reason of the spacing between the first and second conveyor systems and the character of cam roller 46 of the latter. The spacing between conveyor systems is substantially equal to a sheet length, as Shown in Fig. l, and cam roller d has both an active and an inactive conveying portion whereby it is able to move sheets in a periodic manner. When a sheet is discharged by first conveyor system 3l), it comes to rest and stays in that condition so long as the inactive conveying portion of roller 4.6, i. e. the portion with radius Si), rotates adjacent the forward end of the sheet. When the active conveying portion of roller 46, i. e. the portion with radius 51, rotates adjacent the forward end of the sheet, the sheet is grabbed thereby and conveyed forwardly through second conveyor system 45. This arrangement, or equivalents thereof, is comprehended by the description that the spacing between the two conveyor systems is substantially equal to a sheet length.
As the sheet advances from first conveyor system 30 to the aforesaid position of rest, it interrupts a light beam in clutch actuator 95 or, in the example shown, the forward end thereof engages feeler 96. Actuator 9S then functions to effect clutch disengagement to stop operation of feed roller 20. However, sheet 23 continues its advance to the rest position occupied by sheet 161. The sheet when in this position continues to energize clutch actuator 95 which in turn keeps clutch 9) in disengaged condition.
When cam surface 52 picks up sheet 101 and advances it through guides 60 and 61, the rear end of the sheet finally clears the light beam or feeler 96. The clutch actuator is then energized to close clutch 9i? after which feed roller is driven to advance the next following sheet at fast speed from the stack and through first conveyor system 3i) to the rest position where it can be picked up on the next revolution of cam surface 52.
It will be seen that my invention as embodied in this apparatus is effective at all times to position sheets at the rear of second conveyor system 45 so that a single sheet may be advanced by cam surface on each revolution of second conveyor roller 46. The previously referred to impositive action between the friction surface of feed roller 20 and the respective sheets does not adversely affect the operation of my apparatus for the reason that the sheets are advanced at super-linear speed both by feed roller 2t) and first conveyor system 3@ as cornpared with the linear speed of the sheets discharged by second conveyor system 45. The super-speed given to the sheets by feed roller 20 and first conveyor system is, of course, compensated for by the intermittent drive provided by clutch 9i) and clutch actuator 95. When a sheet is advanced from its position at the rear of second conveyor system 45, the next following sheet is rapidly advanced to that position so it may be engaged by cam surface 52 on the following revolution of second conveyor roller 46.
Although not here illustrated, a comber often is provided at the feed tray in order to insure proper feeding. Combers are well known for this purpose and they function mechanically to initiate movement of the top sheets against such deterrents as static electricity, deformed sheet edges, etc.
Apparatus embodying my invention has been found capable of feeding and discharging sheets without interruption at much faster rates and linear speeds than prior apparatus of this character with which I am familiar.
From the above description it is thought that the construction and advantages of my invention will be readily apparent to those skilled in the art. Various changes in detail may be made without departing from the spirit or losing the advantages of the invention.
Having thus `described my invention, what I claim as new and desire to secure by Letters Patent is:
l. A sheet feeding apparatus comprising a framework, a downwardly inclined feed tray mounted on said framework and adapted to hold a stack of vertically disposed sheets, a friction surfaced feed roller mounted transversely in said framework at the forward end of said tray, an arcuate guide below said roller adapted to direct a sheet forwardly of said roller, a first conveyor roller transversely mounted in said framework and spaced Yfrom said feed roller by a distance substantially less than a sheet length, an idler roller cooperating with said first conveyor roller to move a sheet forwardly, a second conveyor roller transversely mounted in said framework and spaced from said first conveyor roller by a distance substantially equal to a sheet length, a segment of said second conveyor roller having an increased radius to provide a cani surface, a roller cooperating with said cam surface to move a sheet forwardly, first means driving said second conveyor roller to discharge a sheet at a predetermined linear speed, second means driving said first conveyor roller to move a sheet forwardly at a linear speed substantially greater than said predetermined speed, a third means adapted to drive said feed roller to move a sheet forwardly at the linear speed provided by said second means, a clutch interposed between said third means and said feed roller and a clutch actuator disposed between said first and second conveyor rollers, said actuator when energized by a sheet being effective to disengage said clutch and when free of a sheet being effective to engage said clutch.
2. A sheet feeding apparatus comprising a framework, a feed tray mounted on said framework and adapted to hold a stack of sheets in position for feeding, a friction surfaced feed roller mounted transversely in said framework at the forward end of said tray, a guide below said roller adapted to direct a sheet forwardly of said roller, a first conveyor system mounted in said framework and spaced from said feed roller by a distance substantially less than a sheet length, a second conveyor system mounted in said framework and spaced from said first conveyor system by a distance substantially equal to a sheet length, said second conveyor system being adapted to move sheets forwardly in a periodic manner, first means driving said second conveyor system to discharge a sheet at a predetermined linear speed, second means driving said first conveyor system to move a sheet at a linear speed substantially greater than said predetermined speed, third means adapted to drive said feed roller to move a sheet at the linear speed provided by said second means, a clutch interposed between said third means and said feed roller and a clutch actuator disposed between said first and second conveyor systems, said actuator when energized by a sheet being effective to disengage said clutch and when free of a sheet being effective to engage said clutch.
3. A sheet feeding apparatus comprising a framework, a feed tray mounted on said framework and adapted to hold a stack of sheets in position for feeding, a friction surfaced feed roller mounted transversely in said framework at the forward end of said tray and adapted to convey away the first sheet of the stack, a first conveyor system spaced from said feed roller in the direction of sheet travel by a distance substantially less than a sheet length, a second conveyor system spaced from said first conveyor system in the direction of sheet travel by a distance substantially equal to a sheet length, said second conveyor system being adapted to convey sheets in a periodic manner, first means driving said second conveyor system to ydischarge a sheet at a predetermined linear speed, second means driving said rst conveyor syssheet being eiective to engage said clutch.
References Cited in the le of this patent UNITED STATES PATENTS