US3598398A - Document feed assembly - Google Patents

Abstract

In a unit-record handling apparatus, an improved record injection and separation combination comprising, in a preferred embodiment, improved throat-separating means including a ''''single-record'''' guiding bevel; improved stack-pusher means adapted to squeeze a record stack into the throat area and improved picker means including a ''''floating'''' pusher wheel arrangement adapted to accommodate irregularities in the shape, the position and the size of the record stack engaged.

Description

0 United States Patent m1 3,598,398

I. [72] Inventors :lcha'dWJIerm- [56] RelereaeeeClted UNITED STATES PATENTS g 'g' m if F3: 3,173,684 s/wes Binzoni 27l/36X FOREIGN PATENTS [2]] Appl. No. 695,210 1,238,045 4/1967 271/36 M i 'm Primary Bummer-Gerald M. Forlenu A he. Am'rmnt Examiner-George F. Abraham W I Attorney-Fred Jacob ABSTRACT: In a unit-record handling epperatue, an improved record injection and equation combination comprie Wm mo mix ing, in a preferred embodiment, improved throat-re aratin IChhe, l ownm. P 8 means Including a "single-record" guiding bevel; improved [52) US. Cl. 271,39, etmk-pueher mean: adapted to squeeze a record stack into the 21418.5 throat area and improved picker means including a "floating" [$1] [n.Cl. I65! 1/00 pueher wheel arrangement adapted to accommodate irregu- [50] Mum 271 418.5 F, laritiel in the shape, the poeition end the size of the record 8.5. .5 .5 A;2 1136,39 ltac engaged.

I bl. I f D -2 DUI P's-b PU-W PATENTEUAUGIOISYI 3 59 ,39

sum 1 OF 3 mvamoxs i RICHARD w. CARMAN L, SIJOHN MERRILL HALLJR 2 VINCE e. DEMP$EY FIG. B PRIOR ART Z ATTORNEY PATENIED AUG 1 0 |97| SHEET 2 [IF 3 FIG. 4

INVENTORS RICHARD W. CARMAN STJOHN MERRILL HALLJR YVINCE G. DEMPSEY B PRIOR ART 3 ATTORNEY 398 3 I 19?: PATEN 0 sum 3 3 FIG- 58 FIG- 5A CAR LJ Ma l DEM a 4 c if fTi DOCUMENT FEED ASSEMBLY PROBLEMS, INVENTION FEATURES in a unit-record handling apparatus, such as document readers, etc. the document injection arrangement (or input feed) typically involves a throat-knife device for document separation so that a related document-picker assembly can thrust documents, singly, from an input stack. For instance, a typical assembly is indicated in FIGS. 1 and 2 where workers in the art will recognize a conventional assembly for injecting documents, such as card D-l, singly from an input stack ST thereof, separating them by driving them through a prescribed throat gap "T3" for downstream transport and utilization as known in the art. This assembly will be recognised as s typical part of a record-processing apparatus for data processing. Such apparatus is fully described in copending commonly assigned U.S. application, Ser. No. 695,177 to Dempsey, filed Jan. 2, 1968 which issued on Mar. 24, 1970 as U.S. Pat. No. 3,502,323 and incorporated herewith. More particularly, stack ST will be understood as arranged along an input-hopper bed Hi! to be thrust by a pusher FP so that the foremost document in the stack indicated) isengaged for injection transport (picking); here, by a pair of synchronously rotating friction drive rolls; picker wheel P-W and pusher wheel PU-W. As understood in the art, these wheels are selectively rotated responsive to a prescribed pick" signal to advance the foremost engaged document along the indicated direction, the driving wheel peripheries defining an engaging pick plane PP. A throating assembly K, or like separation device, is typically arranged to present a prescribed pointed throat edge as indicated in prescribed (adjustable) spaced relation with the periphery of picker wheel P-W to thus define throat gap Tg, this assembly also serving to define a trailing knife surface K-l, a bevel knife surface li-B and a lateral guide surface lt-O (the latter being disposed conventionally displaced from picking plane PP at a right angle (S' OO'). Workers in the art will recognise that such a beveled surface li-B is intended to gradually "funnel card noses to throat 'lg and is typically disposed at an angle B of about 23' with the plane of guide surface K-G (plane PL). Surface li-B typically extends over a prescribed stacking distance 111" corresponding to many document-widths. it will be understood that bevel surface li-B can effect this "funnelling by "camming" documents toward throat gap 'lg so that forward cards in stack 81' are gradually guided closer to T3 under the influence of the picking thrusts, such as from the thrust of wheels F-W FU-W on the foremost card as transmitted through adjacent forward cards. Unfortunately, such a multithlckness" bevel, though quits conventional in the art, introduces several feeding problems. One problem is associated with the arrangement of the stack and the picker means so that nonengaged leading documents, such as those behind D4 in stack 81 and within the span bi of bevel surface K4! are thrust by the picker means against this surface K-B with consequent damage to the document nose (leading edge) such as s splaying or like edge deterioration after a number of feed cycles. Pusher wheel PU-W may so thrust such forward documents each time it picks the foremost document and drives it through throat lg. it is an accepted fact that such knife separation arrangements will eventually damage all documents to a greater or less extent after repeated passes; the problem being to alleviate this tendency so that a sufficient number of passes may be had to render a system practical. For instance, using the indicated type feeding and throatlng arrangement for Injecting cards of "average" characteristics, a significant number will begin to exhibit "splayed edges after six to eight feeding passes, thereafter being difficult or impossible to feed (e.g., causing jams etc.). One would prefer an arrangement where on the order of ID to 20 passes may be made before a significant number of such cards will cause feed problems.

A related problem has to do with nose bending" and will throat knife assembly of FIG. 2 is indicated enlarged together with a departing (throated) card D-1 and a waiting card D-Z. D-Z will be understood as pushed somewhat (by pusher wheel PU-W with force F,,) as well as by pusher FP against the guiding bevel surface K-B with its nose engaged along K-B so as to approach throat 'lg, snapping down past the knife point (from position D-i', in phantom) as indicated when prior card 0-] has cleared the threat. The presence of prior card D-l in throat T; will be understood as contributing to this bending 03-2) of the card nose, as (to some extent) do pusher force F and the resilience of the document itself, etc. Further, it will be apparent that the wider is bevel K-B (bevel depth (1-8) the more pronounced will be this nose bending. Such nose bending qfien has the eflecl' of rmearing, or otherwise distorting, a nose edge (e.g., smear enlargement .rm on nose of card D-Z); usually by abrasion against the knife tip. Such edge damage is most serious with flexible documents, evidently because their resilience allows them to bend more and return loss quickly. This nose bend can also move a document away from its throat destination, sufhclent angular bend acting to resolve the push force F,., to give a significant component normal to the card plane (away from wheel P-W). Of course if the document nose can be stiffened it will bend less, return faster and minimise these problems of edge damage, misalignment, etc.

According to one feature of the invention we have reduced such nose bending and stiffened fed documents by reducing bevel depth radically. That is, we have eliminated the customary cammlng of stacked documents in the aforementioned manner and reduced the width bl of the bevel surface K-B to approximate that of a single-stacked document. As a consequence, the reduction in the aforementioned type of feeding damage that was truly sudden and unexpected. For instance, simply reducing distance bi to approximate the width of a fed document (see bl H0. 4) was found unexpectedly to enable the feeding ofdocum'ents up to 20 to 25 times before a significant number of them appeared to present feed problems. passing documents three to five times before any defects were noticeable.

Another problem associated with prior art knife-separation devices, such as indicated in Fifi. I is related to "double feeding" (sometimes characterised as a "sneak" pick, where two documents, rather than one, are throated). A common reason for this is that although a nominal throating gap T; is referenced from the picking surface (periphery of wheel P-W, the position of this surface may vary e.g., due to an eccentricity in the wheel mounting; surface anomaly, etc.). Controlling gap Tg is thus complicated by the necessity of allowing for such variations and establishing a worst case position for the knife point, thus at times opening up gap "lg. Such a sneak pick" may also be tolerated by resilience in the pusher surface such as a rubber coating on wheel F-W which "gives" when two cards press it. Also, variations in document thickness have to be accommodated, typically adding from i to 3 mils ovsrags with card stock having a nominal thickness range of from 4 to 9 mils respectively. We have also found that this sneak pick problem is aggravated by locating the picker arrangement to define a picker plans PP at exactly 90' to the guiding edge ii-O of the ln-hopper without "sllowing" for the typical offset of the throat due to the bevel K-B. For instance, with a conventional wide bevel as in H0. 3 (dimensions below), we have found that this offset along the curving periphery of wheel P-W adds about 2.5 mils to the straight-through gap (l.e., from knife point to 90' plane PP). Thus. according to another feature, we have found that by tilting this picking plans PP somewhat so as to be exactly 90 with respect to the cross section of the throat T; (rather than with guide edge lt-O), that is, exactly normal to the minimum-gap dimensions, we can alleviate this problem. Such a disposition is indicated along a tilted picking plane PP in the embodiment of FIG. 4. in short, the width bw of the bevel and the curvature of the picker wheel P-W from the guiding edge K-O to the throat gap location makes it unrealistic to reference the picker be described with reference to FIG. 3. Here, the conventional plane P? on edge K-Cl. With conventional feed arrangements.

as in FIG. 2, we have noticed that this problem is the most extreme with the thinner documents; for instance, with a nominal 4-mil document, it will not be too uncommon to find a pair of undersize" documents of about 3.5 mils trying to get through the throat Tg at the same time, thus, unless the throat gap is less than about 7 mile, a sneak pick is sure to occur.

According to another, related embodiment feature, we have found it possible using simple means to so "push" an input document stack as to "squeeze it" with somewhat more pressure on the document noses. Such is indicated in the embodi ments of FIGS. 4 and 5, for instance, the nose of the foremost document will be urged more positively against the picker wheel P-W and not be allowed to bend away from it such as exemplary document D-Z in FIG. 2 is doing. That is, we have found that with an overpressure on the leading edge of the stack ST, document noses may be prevented from jamming, etc, against the knife assembly K, this being simply effected, for instance, by tilting the pusher blade slightly away from the feed plane PP just sufficient to provide this positive nosepusher engagement, preferably also applying push force F, adjacent the leading edges of blade FP. However, this push imbalance must be less than will squeeze out the stack, i.e., urge documents away from the guiding edge K-G. One would hardly expect such ("on the surface") minor modifications as the foregoing to so radically affect the document feeding operation as has been observed; however, hindsight would suggest that perhaps the extremely high feed rate (e.g., at a velocity of about lOO i.p.s., or about 1,200 3-inch documents per minute) makes this arrangement more subtle and sensitive to such changes than one would imagine.

Another typical feeding problem with prior art assemblies like those aforementioned is the type associated with distortion in the overall document stack (deck ST) such as warpage" bow and the like. For instance, with an -inch deck of average cards approximately 4 by 8 inches, machines are typically expected to accommodate an overall tilt" in the deck-width dimension of about 125 mils (and the same amount of bow along the width); plus about a ZSO-mll warpage along the deck length. Related problems are, of course, a bowing along the deck length, a cumulative overthickness in the stacked documents (both illustrated in the embodiments of H08. 5A, SB respectively) and the like. Workers in the art will readily concede that such anomalies in deck cross section have for a long time presented great problems in reliable feeding of unit records, especially at high speeds, and most especially when the stack comprises only the last few badly warped documents. For instance, in the latter case, a picker wheel (such as PW in FIG. 8A) of the conventional type may fail entirely to engage a document surface, with the document thus being advanced erratically or not at all. This problem is also exaggerated when the last few documents in the stack are badly folded, bent, crumpled, etc. According to another embodiment feature, we have found that introducing resilient engagement means on the picker drive, or on the pusher means, or both, in e resiliently floating feeding engagement can practically eliminate such problems. Butprisingly, workers in the art appear to have never addressed this problem in just this way. This is surprising, especially in view of the improved reliability of feeding that we have observed as a result of such floating feeder means.

Accordingly, one object of the invention is to solve the aforementioned and related problems and to provide the aforementioned features and advantages, and related ones, apparent to those skilled in the art. Another object is to provide a document-feeding arrangement and associated throat knife arrangement adapted to guide essentially only the foremost document toward the throat gap. A related object is to provide such an arrangement with picker means disposed along a plane exactly normal to the minimum cross section of the throat. A related object is to provide such an assembly wherein pusher means are provided to preferentially urge document noses somewhat more positively against the picking means, however, without squeezing any away from the throat.

Another, related object is to provide such an assembly including resiliently floating picker means adapted to engage stacked documents for picking. Other objects will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments of the invention disclosed, such as to enable those skilled in the art to practice the invention. This disclosure includes the following drawings wherein like reference symbols denote like elements.

FIG. 1, an upper isometric view of an input hopper-picker arrangement in a typical apparatus for data processing unit record documents;

FIG. 2, a very schematic plan view of a relatively conventional injection arrangement apt for use in the arrangement indicated in FIG. 1;

FIG. 3, an enlarged plan view of throat elements in FIG. 2;

FIG. 4 a plan view of an arrangement like that in H6. 2 including, however, a number of improvement features according to the invention;

FIG. 5 a plan view like that of FIG. 4 showing, additionally, a resilient engagement mounting of a pusher wheel;

FIG. 8A, indicating a typical relation of the arrangement of FIG. 5 with a longitudinally bowed document stack; and

FIG. SB indicating the same arrangement engaged against a stack of overwidth documents.

IMPROVED FEED ASSEMBLY The relatively conventional features of "comparison embodiments in FlGS. 2 and 3 have been discussed and may be borne in mind when considering the novel features of the analogous embodiment features according to the invention in FIGS. 1, 4 and 5. These figures incorporate one or more lmprovement features according to the invention, but otherwise, may be understood as constructed and operating in a relatively conventional manner, such as indicated for FIG. 3. Thus, for instance, the infeed arrangement I? indicated in FIG. l (fregmentarily and with the documents removed) and in FIG. 4, includes a throsting (separating knife) assembly K, a pusher means FF, and s picker assembly P. Assembly P comprises picker wheel P-W and pusher wheel PU-W adapted to thrust the foremost one in stack ST of documents arranged on hopper tray HB singly past the separation throat into transport engagement with downstream processing means (such as the vscuumetic read drum VD in H0. l). Trey H5 is removed in FIG. l to reveal subfloor Sub-H8 above which the springurged push-arm projects to attach at the leading edge of pusher blade PM and establish push force F, aforementioned. More particularly, pusher FF includes flat engaging blade Pr-b and a handle Ps-b being mounted on the sprung arm to be resiliently urged (by means not shown but conventional) to thrust the nose of the document stack 81 with prescribed force (here P, E about 2 pounds) into picking engagement with picker assembly P. This helps to establish the aforementioned squealing action on stack ST. Throating assembly it is analogous to it in FIG. 2 and includes a relatively conventional knife portion W-K mounted (to be adjustable for setting throat gap Tg) in a guide surface K'-Cl, also including a document-cumming bevel surface K-B and a trailing surface K'-T the latter two defining a knife point. The throat knife assembly K will also preferably include conventional throat gap adjust means for translating knife lt'-K to establish different throat settings, such as by the operator pivoting a prescribed adjusting lever to different positions on s reference gauge (neither shown but conventional in the art). Pusher wheel PU-W is mounted for selective rotation on an associeted shaft PU=5, while picker wheel P-W is similarly rotatably mounted on an associated shaft P-S, one of these shafts being driven rotatably by picker drive means (not shown, but quite conventional), with a timing belt P-B coupling the driven shaft in a conventional manner to drive the other shaft in synchronism therewith.

According to one feature of this embodiment, the cumming knife surface, or bevel K'-B is arranged so that its bevel length b1 corresponds approximately to the maximum thickness" of a single anticipated document, such as representative card D'-l in FIG. 4. For instance with a relatively conventional bevel angle B of about 23, a bevel length Bl of about 12 mils has been found quite satisfactory for cardboard stack documents having a thickness of from 4 to 9 mils. Of course a nominal 9-mil card may be within tolerances from 8.5 to 9.5 mils. This may be compared with a relatively "standard" l 12 mil length (e.g., b1 in FIG. 2) at which a significant number of such cards were damaged after just a few passes (e.g., exhibiting seriously splayed edges after six to eight runs); whereas this embodiment allowed on an average of about 15 to passes before any consequent card damage significantly affected the feeding operation. Here, the throat T g was set for about I2 mils, or slightly more than the thickest expected document (9.5 mils), plus machine tolerances of about 2 mils (e.g., runout for wheel P-W, etc.). The aforementioned dimensions etc., of course, were operated with the embodiment including the other characteristics mentioned below. It was noticed on the other hand that where the bevel angle was reduced or eliminated entirely (b1-0 or at least substantially less than a document width and angle B close to zero degrees) that the damage to the documents was somewhat catastrophic, the knife tip acting like a cutting tool and practically destroying many fed cards. Conversely, too great a bevel angle (e.g., substantially more tan 23) is impractical in that it acts to wedge cards into the throat area, cause jams, etc. Another re lated advantage of this "single document" bevel was that the bevel width bw'was reduced such as to reduce nose bending to an absolute minimum, i.e., so that there is practically no tendency of the document to bend its nose adjacent the throat. For this embodiment and this range of documents, bw' was about 5 mils as opposed to a conventional case (such as bw in FIG. 2) of about 47 mils and resultant nose bending document damage, jamming, etc., was reduced.

Another feature of the foregoing embodiment in FIGS. 2 and 4 is the "squaring" of the feed plane PP by tilting it somewhat to be absolutely normal (90) to the throat (minimum throat dimension T9). As aforementioned this tilting is such as to take full advantage of the full cross section of the throat gap (and discourage a sneak pick when a card bends along wheel P-W into a widened gap). That is, when a gap (e.g., T in FIG. 2) is set from the picking plane PP (line of tangency between wheels P-W, PU-W), it must actually be unnecessarily wide because of the radius of the picker wheel P-W along the bevel width bw. For the embodiment of FIG. 2, the radius of wheel P-W adds an offset (from tangent line PP of about 2.4 mils, greatly increasing the danger of double feeding especially with 3.5-mil cards. Thus, according to this feature the tilted picking plane PP was reduced to slightly less than the 90 relation with hopper edge K'-G (normal plane n is 90 with respect to tangent plane :1 comprising, in this em bodiment, about 89% (88), being tilted back about threefourths of I to thereby improve the "entry angle" and reduce the overgap" due to the picker wheel radius aforementioned. Some appreciation of the improvement in feeding operations and the associated reduction in double feeding hazard will be indicated by table below where a few representative nominal document thicknesses are referenced to the throat gap dimension of the improved embodiment in FIGS. 1 and 4 (Case A) as opposed to the more conventional embodiment in FIG. 2 (Case B):

According to another, related improvement feature, infeed embodiment [F in FIGS. 1 and 4 is also modified so that the pusher assembly FP urges the stack of documents ST against the picker means in a prescribed nose-squeezing manner. More particularly, we have found it helpful to tilt the face of pusher blade Ps-b back somewhat further, from the aforementioned (already-tilted) picking plane PP to assume a prescribed angular relation SSP with lateral guide surface K'-G and effect a slight squeezing on the forward portion of stack ST. This pusher tilt will be such that the nose of the foremost document (such as D'l in FIG. 4) is engaged somewhat more positively against picker wheel PW and somewhat less positively against the companion, pusher wheel PU-W. By comparison, we have found that where such a pushing surface is disposed parallel to the picking plane (such as with the blade of pusher FP in FIG. 2) we have found that too little picker wheel-contact is evidently provided at the nose of a document. Such will allow a card nose to wander out of the desired path (e.g., bending as indicated for D-2 in FIG. 2) and striking the knife bevel K-B damagingly, especially in cases of a wide bevel bw where the nose portion will have somewhat less pusher-thrust F, urging it against wheel P-W after it passes the plane of guide edge K-G. Conversely, in some cases too positive an engagement may occur between the foremost document and the pusher wheel PU-W, tending to bend (fold) the document between the two wheels (especially in the case of such nose bending as indicated for D-2) often resulting in damage to the document, jams, etc. In the embodiments such as shown in FIGS. I and 4, we have found that unbalancing the pushing forces exerted by blade Ps-b so that the nose of the foremost document is pushed relatively more than its tail (such as in the case of document D'-l in FIG. 4, somewhat exaggerated) in a nose-squeezing action, results in a minimizing of these problems. For an embodiment like that in FIGS. 1 and 4, we have found surprisingly that the squeeze angle" in FIG. 4) is somewhat critical (here being about 94 to l). That is, we have found that while this angle must be sufficient to tip the blade in against the nose of the stack sufiicient to squeeze the noses of the foremost documents, positively against the picker wheel without jamming them (here, about one-half to three-quarters of 1 was insufficient with a spring load of about 2 lbs. on the pushing blade Ps-b coupled adjacent the leading blade edge); on the other hand, it cannot be so much as to initiate stack "squeeze-out, that is, urge some of the documents in the stack away from the throat knife K (here, slightly over 1 appear to initiate this) This squeezing action can also help overcome nose bend problems. Of course, this squeeze angle SO will depend upon the effective thrust force applied across the engagement length of blade Ps-b and will also depend upon the typical document stiffness (e.g., very short, thick documents of heavy card stock, for instance, might be very stiff and require a larger squeeze angle than thin, longer, more resilient documents with a floating pusher wheel PU-W (cf. below) exerting about K's-pound pound spring load on stack ST and pusher F exerting about 2pounds, a desirable squeeze action is achieved. To summarize, such squeezing increases the engaging forces for the picker wheel and decreases those for the pusher wheel (preferably in a 4:] to 2:] ratio), thus tending to pull, rather than push, a picked card.

According to a further feature, related to those above and exemplified in the embodiment of FIGS. 5, 5A and 5B, the pusher wheel is mounted so as to comprise resilient, floating means for driving document tail portions through the throat. Such a resilient contact means is indicated in FIG. 5 as generally comprising a suspension arrangement resiliently floating pusher wheel PWu-W so as to normally present its pushing surface along tilted pushing plane PP (in prescribed angular relation fp with the normal n to guiding edge K'-G) to be resiliently displaceable more or less than this angular relation as indicated in FIGS. 5A and 5B respectively, in response to document positioning farther away from or closer to wheel Pu-W. That is, in FIG. 5, the feeding assembly may be assumed to be the same in all respects as the aforegoing embodiments in FIGS. 1 and 4, except for the following described refinement features. However, for clarity and simplicity, certain features are not here shown, such as the "squeezing" attitude of the pusher plate FP. Here, an illustrative "normal" stack of documents -ST will be understood as disposed in relatively normal condition engaged relation with pusher wheel Pu-W. Wheel Pu-W is rotatably, and drivenly, mounted on a prescribed rotatable bracket A (rotatably journaled in the machine frame) to assume a prescribed normal angular relation PO-l with the front of stack 5-81 for pushing the foremost card D-a, a distance, then beginning to push the following card D-b, etc. it will here be assumed that the aforedescribed improvement features, such as the single document bevel, and the squeezing pusher are incorporated to cooperate with this floating suspension pusher assembly. This suspension may be sprung in any conventional manner, such as with schematically indicated compression coil spring SP and will be preferably stop-limited, such as between the pair of forward and rear stops SFR, SR schematically indicated (e.g., providing a swing of about a few degrees either side of plane PP). Here it may be understood that the angle PO-l' is about L5", the pusher force F, is about 2 pounds (sd jacent the leading edge of the stack 5ST and that the spring force SF is about one-quarter pound, preferably constantly applied (i.e., bracket A never bottoming against either stop). The documents in stack S-ST will be assumed as normal and regular in their size and orientation, presenting fist, parallel surfaces to the pusher plate and pusher wheel.

Extreme stack conditions are indicated in FIGS. SA and 53 by way of illustrating the advantages of this pusher wheel suspension and the floating push contact, it affords. For instance, in FIG. 5A an abnormal "bowed-in" stack of documents SA-S'l is indicated representstlvely and comprises s number of documents M, 0-? etc. (whose leading or trailing ends, or both, are warped longitudinally, out of line with their central body (shown warped toward pusher wheel Pit-W, though the opposite is also contemplated This condition will, as illustrated, displace the centrsl body of stack lA-ST farther away from pusher wheel Pu-W than normal, in response to which the spring suspension will urge the wheel out beyond the normal (tilted) picking plane PP to frlctionslly engage it for pushing the foremost document (with the relatively constant 'k-pound force). Of course forward stop SFR will limit this action.

A contrary case is indicated in FIG. 8-! where s bowedout" document stack 58-81 is indicated comprising documents (e.g.. D-O, D-li') having their longitudinal center body portions projected beyond the plane of their ends. That is these documents will be presented somewhat closer to wheel PU-W thsn normsi in s convex stack which includes documents that are overly thick at their center, or warped. bent or crumpled there. etc. Again, the fiosting resilient mounting will allow wheel Pu-W to be resiliently thrust back behind the normal picking plane as indicated, within the limits tolerated by back stop SR.

Such a floating pusher wheel suspension is also observed to compensate for any localised "hang-up in the deck as the stack is pushed along the infssd assembly by the pusher piste PP toward wheel Pit-W. That is, workers may appreciate that as cards are picked from the stack and the stack moved by pusher piste FF towsrd picker whssl Pu-W to present successive cards thereto, certsin anomalies in stack trsnslstion can occur. For instance, we have observed that in many cases the stack will not move in s constant grsdusl manner, but in incremental jumps, presenting foremost documents at varying positions from the intended picking plane (as much as ill-mils displacement observed). Of course a stack of documents is quite compreslihle and this is believed to cause movement across the infeed assembly in oscillatory increments with an "accordionlike action. it will he evident that without the uforcdescribed floating suspension of pusher wheel Pu-W. it could not "follow" the stack during these variances and would radically change its frictional engagement, so that documents would, at times, be pushed too little, at times not at all! This feature eliminates this and maintains a relatively constant (spring) engagement load on each foremost document, shifting the wheel position to meet it where necessary. Thus, a relatively constant push wheel drive is provided independent of stack shape or (within limits) location. Moreover, this floating push wheel cooperates nicely with the aforementioned squeezing push piste F? to pull (not push only) documents through the throat. Thus, plate FP will act to assure that a relatively constant force (F?) urges the foremost document nose against picker wheel P-W, while the floating push wheel Pu-W will follow the trailing portions of this document, engaging them with a relatively constant frictional force. Where such a floating push wheel is not employed, care should otherwise be taken to assure that the picker wheel always engages documents with more force than the pusher wheel (at least 2 to 3 times the nominal A-pound pusher wheel contact lest problems arise). It will be appreciated that in any event, such a resilient floating push wheel means provides a relatively light constant pushing-engagement with trailing portions of stacked documents for more constant driving thereof despite abnormal document condition, and especially in the case of the last few documents in the stack; a very small stack being typically difficult, at times impossible, to feed reliably especially when the documents are at all distorted. For instance, in prior an arrangements when the last few documents in the stack were in a seriously crumpled or otherwise distorted condition, they would simply not feed, often jamming sgainst the throat knife (e.g., this is apt to happen with the more conventional arrsngements such as indicated in FIG. 3).

A feature related to this floating pusher wheel suspension is the spring finger SF indicated in FIGS. 1 and 4, ss projecting from the face of pusher blade Pr-b to resiliently engage a document stack pushed thereby. Finger 8? msy comprise a light flesure leaf or like spring arranged to thrust an engaged stsck towsrd pusher wheel Pu-W with a prescribed light spring force and is often very useful in maintaining a very small stack properly engaged with Pu-W (e.g.. when the last few cards are badly crumpled or warped). For convenience. finger SF may be mounted from behind plate Ps-b to project therefrom through s suitable aperture as illustrated. However. such s finger cannot. by itself. function in place of the aforementioned floating pusher wheel suspension. e.g.. it cannot compensate for the "accordion effect." though it may be used cooperatively with it.

The sforedescribed machine features cosct together quite advantageously. although in certain instances. they may also be used sepsrstely. The interaction of the squeezing push piste and the hosting push wheel were described. Also the floating push wheel can discourage squeeze-out. The single document bevel feature oooperstss with both these other features to reduce nose bend and like problems to a minimum and assure a positive. clean passage of s fed nose through the throat gap.

The foregoing description of the improvement features of the invention msy be clarified and better understood and apprecisted in connection with the following description of a typical feeding operation. For this purpose, it will be assumed that a stack of documents (a psclt) of a prescribed type are inserted onto the trsy surface i-iB of the lnfeed assembly IF, the pusher arrangement being retracted to admit these and rslesssd to automatically thrust the stack against the picking plane defined between picker and pusher wheels P-W, PU-W. An initial "feed command." or pick slgnsl. will activate a velocity servo means (not shown but conventional) and associstsd picker drive means to sccelerste these (picker and pusher) wheels to a driving surface speed of about I00 i.p.s. The nose of the foremost engaged document in the stack will then be driven toward the throat knife and through gap T3 and onto the vacuum drum VD (see FIG. I) which will be turning in the indicated direction, also at a surface speed of about i.p.s. As the trailing edge of the first fed document passes beyond pusher wheel PU-W, the latter will urge the next stacked document toward the throat knife (cf. D-Z, FIG. 2), and when the first document clears the throat gap 'l'g this second. successor document will be driven to follow it through [3, the wheels continuing to drive (that is, a "chain feed is assumed with the documents driven in abutting, nose-to-tail relation). This condition exists for approximately milliseconds until the tail of the first document entirely clears the throat block, at which point the vacuum forces on drum VD (or something equivalent) will quickly and strongly flip this tail out of the "nominal path" and toward drum VD somewhat pivotingly. This action triggers the throat photodetector means (operating along the detect axis between source 2-8 and cell 2-C, FIG. 1) by allowing a light beam to pass between the two documents momentarily to generate a "spacing command" which may be employed, for instance, to decelerate the velocity servo and stop the picking action of wheels PU-W, P-W (until the next pick command). This deceleration is preferably effected in conjunction with the subsequent interruption of this detect beam by the following document nose (of the second document), for instance, registering this nose edge almost exactly along this detect axis (or a prescribed minor distance therebeyond). This document is thus, preferably. prethrosted" and registered at a prescribed constant picking location for the subsequent pick command. The document on drum VD may then be advanced through a processing zone (e.g., for reading. etc.) and then be captured by a downstream transport system for subsequent handling. Workers in the art may visualise other analogous structural and operational features equivalent to those taught above. While in accordance with the provisions of the patent statutes, the above has illustrated and described preferred forms of the invention in their application, it will be apparent to those skilled in the art that changes may be made in the apparatus described without departing from the spirit and scope of the invention as set forth in the appended claims and that in some cases, certain features of the invention may be used to advantage without a corresponding use of other features. while certain features may be changed or substituted for equivalently as appreciated by those skilled in the art.

Having now described the invention, what we claim as new and desire to be secured by Letters Patent is:

l. in a document-handling apparatus including a document injection station for receiving a stack of documents in prescribed alignment along a reference bed surface and trans port means for translating said documents singly from adjacent said bed surface to downstream processing and handling stations. the combination therewith of:

an infeed assembly including means defining a threat opening for receiving the foremost document in the stack;

inject means forming one edge of said throat opening for urging said foremost document into engagement with said transport means;

compression means for urging said stack along said bed surface whereby said foremost document engages said inject means; and

guide means extending substantially parallel to the plane of said throat opening and being offset from the plane of said opening toward the position of the documents for referencing the edges of the stacked documents along a plane extending parallel to the plane of said throat opening, and camming surface means tapering from said guide means to a point opposite the inject means to form another edge of the throat opening, said camming surface means having a prescribed bevel length less than the thickness of two of said documents.

2. The combination as recited in claim 1 wherein for a stack of documents having a nominal thickness of 9 mils, the tapered camming surface means having an angle on the order of 20 to 30 with a depth of about 4-6 mils and a bevel length of about l0-l5 mils, there being comparable dimensional and angular adjustments for stacked documents of other thicknesses.

3. The combination as recited in claim 1 wherein said compression means of said infeed assembly includes a squeezing pusher plate means adapted to press the leading portion of a document stack against the inject means considerably more than trailing portions thereof.

4. The combination as recited in claim 1 wherein said inject means comprises a picker transport means disposed in relatively fixed relation with the leading portion of each foremost stacked document and a pusher transport means disposed in contact relation with trailing portions of this foremost document. the inject plane between these two transport means being such as to be substantially exactly orthogonal with the narrowest throat cross section for a normal, undistorted stack of documents; and wherein said pusher plate is tilted slightly away from the inject plane defined by said inject means, and along which documents are to be injected through said throat, this tilt being on the order of a few degrees, sufficient to preferentially press the nose of the foremost stacked document against said picker transport means considerably more than the rest of the foremost document is pressed against the pusher transport means.

5. The combination as recited in claim 4 wherein said squeezing tilt of said pusher plate back from the inject plane is not substantially more than about i with about 4-lbs pusher bias.

6. The combination as recited in claim 5 wherein the inject plane is. itself. aligned to be exactly with respect to the minimum throat cross section.

I. The combination as recited in claim 6 wherein this squeezing pusher plate is spring-loaded adjacent its leading edge to compress the stack nose against the picker transport with on the order of a few pounds force.

8. The combination as recited in claim 7 wherein said pusher plate additionally includes a resilient spring contact finger projecting from the flat. stack-engaging surface thereof to assure the positive engagement of a minimum width stack against said pusher transport.

Claims (8)

1. In a document-handling apparatus including a document injection station for receiving a stack of documents in prescribed alignment along a reference bed surface and transport means for translating Said documents singly from adjacent said bed surface to downstream processing and handling stations, the combination therewith of: an infeed assembly including means defining a throat opening for receiving the foremost document in the stack; inject means forming one edge of said throat opening for urging said foremost document into engagement with said transport means; compression means for urging said stack along said bed surface whereby said foremost document engages said inject means; and guide means extending substantially parallel to the plane of said throat opening and being offset from the plane of said opening toward the position of the documents for referencing the edges of the stacked documents along a plane extending parallel to the plane of said throat opening, and camming surface means tapering from said guide means to a point opposite the inject means to form another edge of the throat opening, said camming surface means having a prescribed bevel length less than the thickness of two of said documents.

2. The combination as recited in claim 1 wherein for a stack of documents having a nominal thickness of 9 mils, the tapered camming surface means having an angle on the order of 20* to 30* with a depth of about 4-6 mils and a bevel length of about 10-15 mils, there being comparable dimensional and angular adjustments for stacked documents of other thicknesses.

3. The combination as recited in claim 1 wherein said compression means of said infeed assembly includes a squeezing pusher plate means adapted to press the leading portion of a document stack against the inject means considerably more than trailing portions thereof.

4. The combination as recited in claim 1 wherein said inject means comprises a picker transport means disposed in relatively fixed relation with the leading portion of each foremost stacked document and a pusher transport means disposed in contact relation with trailing portions of this foremost document, the inject plane between these two transport means being such as to be substantially exactly orthogonal with the narrowest throat cross section for a normal, undistorted stack of documents; and wherein said pusher plate is tilted slightly away from the inject plane defined by said inject means, and along which documents are to be injected through said throat, this tilt being on the order of a few degrees, sufficient to preferentially press the nose of the foremost stacked document against said picker transport means considerably more than the rest of the foremost document is pressed against the pusher transport means.

5. The combination as recited in claim 4 wherein said squeezing tilt of said pusher plate back from the inject plane is not substantially more than about 1* with about 4pounds pusher bias.

6. The combination as recited in claim 5 wherein the inject plane is, itself, aligned to be exactly 90* with respect to the minimum throat cross section.

7. The combination as recited in claim 6 wherein this squeezing pusher plate is spring-loaded adjacent its leading edge to compress the stack nose against the picker transport with on the order of a few pounds force.

8. The combination as recited in claim 7 wherein said pusher plate additionally includes a resilient spring contact finger projecting from the flat, stack-engaging surface thereof to assure the positive engagement of a minimum width stack against said pusher transport.

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