US2649303A - Sheet-feeding and turning apparatus - Google Patents

Description

Aug.- 18, 1953 R. N. FULLER SHEET-FEEDING mu TURNING APPARATUS Filed Oct. 17, 1951 4 Sheets-Shut 1 I INVENTOR.

9M Q, BY M11 RICHARD N. FULLER ATTORNEYS Atig.;. 18, 1953. R. N. FULLER SHEET-FEEDING AND TURNING APPARATUS Filedfl'ct. 17, 1951 4 Sheets- 5399"; 2

m s 5 u N mm m Fm T w. 2 T m W m w QM Nu Aug. 18, 1953 R. N. FULLER 2,649,303

fil-IEET-FEEDING AND 'rumufic APPARATUS Filed Oct. 17, 1951 4 SheetSi-Sb'efit s Frq.5

RICHARD N. FULLER INVENTOR.

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' ATTORNE fs '4 Sheets-Sheet 4 Filed Och 17.19 51 RICHARD N. FULLER INVENTORQ Q BY W ATTORNEZS l atented Aug. 18 1953 SHEET-FEEDING AND TURNING APPARATUS Richard N. Fuller, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application October 17, 1951, Serial No. 251,697

8 Claims.

This invention relates to sheet-feeding apparatus, and particularly to an apparatus for feeding sheets individually along a given path to a discharge point where they are stacked and including means for automatically turning over selected sheets as they reach the discharge point in order to cause the natural curl of adjacent sheets to offset each other.

In certain enterprises using individual cut sheets of paper or other flexible material, it is essential that the sheets be flat rather than curled. One enterprise in which curled sheets are particularly troublesome is the photographic finishing business where cut sheets of film and light-sensitive paper are used and must generally be held flat in a focal plane for exposure and should be flat to facilitate certain processing procedures to which the sheets are subjected. Cut sheets of photographic materials are particularly subject to curling tendencies because they are coated on one side with light-sensitive coatings which have different stretch or shrinkage characteristics than the base of the sheet.

In order to present a package of flat sheets of paper to the customer, at the present time it is the practice to turn over alternate sheets in the package so that the curling tendency of adjacent sheets will offset each other. This not only requires the attention of an operator, but is such a tedious procedure that an operator cannot be relied upon to carry it out properly for a full working day and day after day. At the same time, the full attention of an operator for this job adds a considerable item to the cost of packaging such sheets.

The primary object of the present invention is to provide an apparatus for feeding individual cut sheets to a stacking point and which includes means for automatically turning over selected sheets as they approach the stacking position.

Another object is to provide a sheet-feeding apparatus of the type described in which the sheet-turning mechanism is selectively set, into operation through a control unit when the leading edge of the sheet passes a given point in the path of travel of the sheets in advance of the turning mechanism and which control unit can be made to turn every sheet, every other sheet, or anyselected sheet as desired.

A further object is to provide a sheet-turning mechanism which is adaptable to any type of sheet-conveying means which feeds the sheets forwardly in a flatwise condition, and which positively grips the leading edge of a sheet being moved along a given path and carries said lead- 2 ing edge of the sheet through an arc away from said path while the trailing edge of the sheet continues to be fed along said path, and which can depositthe sheets directly in a stack without in any way damaging the sheet turned thereby.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its methods of operation, together with additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings in which:

Fig. 1 is a side elevation of a sheet-feeding and stacking apparatus constructed in accordance with a preferred embodiment of the present 'invention and having a portion of the side supporting frames broken away so as to show the parts of the feeding apparatus and their drives in full lines instead of dotted lines;

Fig. 2 is an end view of the feeding and stacking apparatus shown in Fig. l and looking from the end thereof at which the sheets are stacked;

Fig. 3 is an enlarged elevational detail of the sheet-turning mechanism and showing the same in an operative position where it is just engaging the leading edge of an advancing sheet;

Fig. 4 is a view similar to Fig. 3, but showing the sheet-turning mechanism advanced to a position where the leading edge of a sheet has been moved out of the feeding path and has engaged the sheetv stops to release it from the turning mechanism; and

Fig. 5 is a wiring diagram of one form of electrical control circuit which may be used for selectively energizing the clutch of the turning mechanism.

According to the invention, cut sheets are individually advanced along a given path in a flatwise condition to a discharge point where they may be stacked or otherwise disposed of. Adjacent the discharge point in said path there is located a selectively-operated sheet-turning mechanism which is adaptedto turn over selected ones of the advancing sheets as they pass the discharge point. This sheet-turning mechanism comprises a sheet pick-up member which is adapted to be moved from a normal inoperative position, wherein it merely serves to guide said sheets along said path, to an operative position, wherein it grips thev leading edge of an advancing sheet. In moving from this operative position back to its normal inoperative position, the pick-up member carries the leading edge of the sheet in gravity and land on a plane below that of the path defined by said conveying means. The sheet pick-up member is set into motion bya'single revolution clutch which is actuated by a solenoid whose energization is controlled in response to a signal received by a control @mm t j tne leading edge of a sheet passing a given detector station in said path in advance of the pick-up member. Means are also provided whereby the control circuit can be made to by-pass only the signal created by every second sheet passing the detector station, thus passing alternate sheets straight through the discharge point andturriing alternate sheets. 7

Referring now to the drawings wherei'na preferred embodiment of the present invention is shown, the sheet-feeding and turning apparatus is supported by a framework coinprising a hori-' zontal base I6 from which a pair of vertical side frames I I extend in spaced relation to serve both as supports for the sheet-conveying mechanism and its drives as well as serving as covers for this mechanism. The sheets S of flexible material, such as paper, to be handled by this apparatus are moved along by a plurality of narrow endless horizontal conveyor belts I2 supported on rolls I3 fixed to shafts I6 extending between the side frames II. One of the shafts I4 is driven by a chain I5 engaging a sprocket IE on the end of one of the shafts I4 and a sprocket H on the end of another shaft I8 extending between the side frames II in parallel relation to shafts I4. This latter shaft I8'is, in turn, driven through a chain or belt I9 and sprockets land 8, sprocket I being fixed to shaft 35 extending between the side frames II and being. continuously driven by a motor M throughfchain 36 engaging a sprocket 3 fixed to shaft 35, see 1. Although, as shown, the sheet conveyor is made up of eleven narrow belts, see Figs. 2, it will be understood that a less number of belts, even a single belt, could be used. The sheets S can come from any source, the only requirement be% ing that they be placed on belts I2 flatwis'e' and in spaced relation. One representative source of such sheets might be a chopper which inter: mittently chops acontinuous web of paper into sheets of a given length and drops the sheets 'di re'ctly on belts I2 or onto another conveyor belt which feeds them onto belts I2. In Fig. 1, I have shown my feeding apparatus associated with such a belt B which feeds the sheets from a chopper to the belts I2. V

The sheets S are held fiat on the lower conveyor belts I2 by means of upper conveyor belts corresponding in width and number tobolts 12 and carried on rolls 2I mounted' on shafts22 extending between the side frames in parallel relation to shafts Id. The lower reach of the upper conveyor belts may directly contact the upper reach of the lower conveyor belts to be driven by frictional contact if the rolls I3 are fixed toshafts 22 and said shafts are mounted in bearings for free rotation as indicated. On the other hand, therolls 22 may have their ow'n drive, if desired, in which case the'speed of movement of the two belts should be the same.

These conveyor belts feed the sheets S to a dis charge point where they are deposited in a stack indicated at 23 on asuitable pallet 24 supported by ashelf 25 supported onpillars 26.

If only the conveyor belts were used, the sheets S would all be discharged onto; the stack with the same side up as wasup during movement to the stack. In order to present a package of flat sheets, the apparatus is provided with means for automatically turning every other sheet as it i's'dep'osited on the stack so that the curling tendencies which the sheets might possess will act to counteract one another. Tg-tlli end the; apparatus is provided with a sheet-turning; mechanism comprising sheet pickup members in, the form of rolls 2'! fixed to a shaft-28 extendi'ngbetween, and journalled in, the side frames II at the discharge point of the conveyor belts. In the arrangement shown, there is a pick-up roll 21 located. between each pair of conveyor belts I2 and, while the major portion of the peripheries of these 1 0115 is circular, there is a raised portion 129 on the periphery of each roll provided with anotch 30 into which the leading edge of a sheet Sis adapted to be red when the pick-up rolls 2? re in n operative position, as shown in Fig. 3, wherein the raisedportion 29 of the rolls extends into thepathof the sheets S carried by the cbnveyorbelts 42am notch 36 is in a position to accept the leading edge of the sheets. I v g The drive for the pica-unions 21 comp chain 3| engaging asprocket 32 flied to saft 28 and a sprocket'33 connected 't'othe Ten member of a single revolution/clutch s r-w (in is in turn frictionally connected to said shaft 35 which is continuously driven hrough achain or belt 36 and sprocket at fro motor drive to the pick-up rolls isinterrupt'ed when a pivotedpawl 31 engages a single-tooth ratchet 38 on the driven member of the clutch, is started when pawl 311s retracted from engagement with the ratchet. Theawl 31 is retracted from engagement with the ratchet. Thepawl 37 is normally moved to its operative p tion by a spring, and ismomentarily withdrawn from this position by. energization of asolenoid 39. The pawl 3? norhiallydi sengags the clutch to stop the pick-up rolls 2'! whenth enotch e's an therein are out of the path of the sheets s andin the position shovvn' in g. 1. In position of the r0113 21 their periphery, lies siibsta'nti'ally tan'gent to the plane or the upper reach of'the lo'w'er conveyor b'eltsand c'ohsti tutes a guidesurface for the'sh'et's moving to the stack without being turned. Theupper conveyor belts 20 preferably extend beyondthe lower conveyor belts, I2 and over the pick-up rolls 21 so as to hold the sheets, which are to be turned, flat as they approach the notches in in the pick-up rolls and to guide that sheets not being turned into ntact with the peacher'y of the pick-up rolls and thus direct the sheets properly onto the stack v I Abeam 'of light is direptcaerbss th'e'p'ath or the sheets from a lamp 40 contained in a lamp house 4I located below, and between two of the lower conveyor belts I2. This beam 'of ligh'tis picked up by aphotocell 42 contained ahousing 43 disposed aboveand between the same two conveyor belts that the lamp house is located between. Suitable lenses are pla ced'in the lamp house and photocell housingto focus the light to a narrow beam at the path of the sheets. The photocell is connected into a suit able electric control circuit indicated by a box 44 in Fig. 1 which, in turn, controls the energization ofsolenoid 39. Thus, when the leading edge of the cut sheets intercepts the light beam, the solenoid is energized, thus tripping the single revolution clutch and setting the sheet pick-up rolls 2'! into motion.

The photocell scanning system is so spaced from the discharge point of the conveyor system that by the time the leading edge of a sheet which tripped the solenoid reaches the discharge point, the pick-up rolls 2'! have moved to the position shown in Fig. 3 wherein the notches therein are in a position to receive the leading edge of said sheet. The linear speed of the pickup rolls 2! is slightly less than that of the conveyor belts so that the leading edge of a sheet is caused to be fed into, and held in, thenotches 30 in the rolls. Rotation of the pick-up rolls forms the sheet around its periphery, thus carrying the leadin edge of the sheet downwardly and away from the path formed by the conveyor belts while, at the same time, the trailing edge of the sheet continues to be fed along in a horizontal direction. As the leading edge of the sheet reaches a point substantially orthogonal to the horizontal sheet path, and at just about the time the trailing edge of the sheet leaves the discharge point, the leading edge of the sheet engages, and is stopped by, fixed sheet stops extending across the periphery of the pick-up rolls on either side thereof. With the leading edge of the sheet stopped and disengaged from thenotches 30 at this point, While the conveyor belts continue to feed the trailing edge of the same, the sheet is flipped over onto the stack as indicated in Fig. 4. The pick-up rolls 2'! continue to rotate to their inoperative position wherepawl 31 reengages ratchet tooth 38 to disconnect the clutch 34.

All sheets may be turned over in this manner if desired. However, in the present instance where the primary object is to present a package of fiat sheets, and to do this by making the curl tendency of one sheet to counteract that of another, it is desirable to turn alternate sheets as they are stacked. To do this, a switch can be installed into the control box to by-pass the impulse created by alternate sheets cutting the light beam, thus passing the alternate sheets straight through to the stack while the pick-up rolls 2? remain at rest. While any number of difierent control circuits may be used to selectively energize the solenoid 39' upon the leading edge of alternate sheets passing the light beam within the scope of the present invention, I have schematically shown, in Fig. 5, one circuit which will accomplish the desired result. This circuit is essentially an electronic counting and switching circuit including the well-known Eccles- Jordan trigger circuit that can be flipped from one stable state to the other by one pulse and back to its original stable state by a second pulse. The trig er circuit or counterstage is arranged so that it passes on one pulse for each two that it receives. In the present instance, the operating negative pulses come from thephotocell 42 when it becomes dark, said pulses being passed through a two-stage amplifier. tube prior to reaching the trigger circuit. The alternate pulses passed by the trigger circuit are fed to the grid of a thyratron to cause the same to fire and, when the thyratron fires, thesolenoid 39 is momentarily energized when a condenser discharges through the thyratron and. acts to cut-the tube off. This produces a momentary efier'gization of thesolenoid 39 every second time the photocell becomes dark and, accordingly, trips the clutch 34 each time alternate sheets pass the scanning station so as to turn each alternate sheet. By adding more Eccles-Jordan trigger circuits to increase the chain of counterstages of the control circuit, the number of sheets passed without turning can be readily altered. By the same token, if the Eccles-Jordan trigger circuit is removed from the control circuit and the output of the amplifier is directly connected to the grid of the thyratron, then the solenoid will operate on every pulse received'and every sheet will be turned.

To elaborate more on the control circuit and its operation, thephototube 42 is coupled to the first stage of a two-stage amplifier tube Vi by a resistance-capacitance coupling so that, as the photocell becomes dark, a negative pulse is applied to the grid of the first stage of tube V1 as indicated by the polarity signs in Fig. 5. This causes the late of the first stage of tube V1 to become positive and the plate of the second stage to become negative. The negative voltage pulse from the second stage of the amplifier tube V1 is used to switch the Eccles-Jordan trigger circuit consisting of tubes V2 and V3, here shown as contained within a single envelope, by being applied to the control grids of these tubes through capacitor C. As is Well known, the Eccles-Jordan circuit is a two-stability trigger circuit wherein in each stable state one tube is conducting while the other is cut off. This circuit can be flipped from one stable state to the other by one negative voltage pulse received from the amplifier and back to its original stable state by a second pulse. Therefore, since the trigger circuit only passes on one pulse for each two that it receives, the output thereof can be used to trip thesolenoid 39 in response to alternate sheets passing the scanning point. The output of the trigger circuit is connected to the grid of the thyratron V4 so that the pulses passed thereby will fire this tube. The coil ofsolenoid 39 is connected in series with a capacitor C3 across the line in parallel with the plate and cathode of the thyratron so that, when the tube V4 is cut oif, the capacitor will be charged to the voltage across the line, 320 v. in the instance shown. The resistance R4 is chosen of such value that, during charging of the capacitor C3, sumcient current will not fiow through the coil ofsolenoid 39 to pull it in. Now, when the thyratron fires, a conductive path is provided for discharge of the capacitor C3 in the direction from the plate to the cathode. This discharge of the capacitor not only energizes the coil ofsolenoid 39 to release clutch 34 but almost immediately cuts off tube V4, thereby allowingpawl 31 to return to its clutch-disengaging position and setting the control circuit up for subsequent operation in response to the next alternate sheet passing the photocell. In the event that sheets are being stacked which may be coated on one side, and thus require that the first sheet placed in the stack be fed straight through and not turned, a reset button, not shown, may be placed in the trigger circuit to insure that the first sheet passing through the apparatus upon startup will or will not be turned, as desired.

It will be understood that, while I have shown the apparatus with a photocell scanning system and an electronic counter and switching control responsive thereto to turn certain sheets, the

present invention is not limited to the. use of such means. For instance, the passageof the leading edge of the sheets past a certain point in their path could just as well be detected by other means, i. e., a feeler finger operating a microswitch, and a control circuit for energizing thesolenoid 39 in response to certain sheets pass.- ing the selected point in the sheet path could .be a system of interconnected relays. The advantage'of the photocell scanning and electronic control unit is that they are rapid in response and will allow a rapid'sheet feed to be used.

While I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be limited to the precise details of construction shown and described, but is intended to cover all modifications coming within the scopeof the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a sheet-feeding and stacking mechanism the combination with means for conveying individual flexible sheets separately and in a flatwise condition along a given path to a discharge point, of a sheet pick-up roll mounted at said discharge point and having a sheet-engaging portion adapted to receive and confine the leading edge of a sheet moving along said path, means for rotatably mounting said pick-up roll to rotate in the direction of feed of the sheets from a normal inoperative position, wherein its sheet-engaging portion is removed from the path of said sheets and through an operative position wherein the sheet-engaging portion is in the path of said sheets to receive and confine the leading edge of the sheet approaching said discharge point after which rotation of said roll carries said leading edge away from the path of said conveying means at a slower rate than that at which the conveying means advances the traile ing edge of said sheet and while the conveying means continues to move the trailing edge of the sheet along said path to continually force the leading edge of the sheet into confining relation with said sheet-engaging portion, means for selectively driving said pick-up roll one revolution at a time at said specified rate from its nor-,- mal position, through said operative position, and back to said normal position, means responsive to the leading edge of a given sheet approaching said discharge point for instigating the drive for said pick-up roll, and means for engaging the leading edge of said sheet to disengage it from said sheet-engaging portion of said pick-up roll when the leading edge is displaced su fficiently from said path to cause the sheet to he turned over as the result of the continued feeding of the trailing edge along said path.

2. In a sheet-feeding and stacking apparatus the combination with means for conveying individual flexible sheets separately and in a flatwise condition along a'given path to a discharge point'above the plane in which the sheets are to be stacked, a sheet pick-up roll having a raised portion on its periphery provided with a sheet-engaging notch, means for rotatably mounting said pick-up roll adjacent said discharge point so that its periphery lies substantially in the path of said sheets while said sheetengaging notch is adapted to interrupt said path, means for rotating said roll in the direction of movement of said sheets withrthe open end of said notch trailing and directed toward the advancing sheets, means normally holding said roll in an-inoperative position with .its sheet-engagingnotch'removed from said path and for limiting said roll to a single revolution, means actuated bytheleading edgeof a sheet passing a given point in said path for releasing the holding means for saidroll whereby said roll rotates to move said sheet-engaging notch into said path to receive'and grip the leading edge of said sheet and carry it away from said path while the trailing edge of said sheet is moved along said path by said conveying means, and a stop member adaptedto engage the leading edge of said sheet gripped by saidroll to disengage it from said notch as the same reaches a point sufficiently displaced from said path to cause the sheet to be turned over as the result of continued-movement of the trailing edge along said path.-

3. A-sheetefeeding and stacking apparatus ac.- cording toclaim'z, characterized by the fact that the peripheral speed ofthe pick-up roll is less than the linear speed of the sheet-conveying means at said discharge point whereby said conveying means serves to'feed said sheets into gripping relation with the notch in said pick-up roll and acts to feed the trailing edge of said sheets along said path faster than the leading edge is directed away from said path by said pick-up roll.

4. In a sheet-feeding and stacking apparatus the r combination-with means for conveying individual flexible sheets separately and in a flatwise condition along a given path to a discharge point above the plane in which the sheets are to be stacked, asheet'pick-up roll having a raised portion on its periphery provided with a sheetengaging' notch, means for rotatably mounting said pick-up roll adjacent said discharge point so that its periphery lies substantially in the path of'said sheets-while said sheet-engaging notch is adapted to intercept said path, means for rotating said roll in the direction of movement of said sheets with the open end of said notch trailing and directed toward the advancing sheets to grip the leading end of a sheet and carry it on its periphery away from said path, said means including a tendency drive and a single revolution clutch between said roll and drive adapted to disconnect said roll from the drive in an inoperative position where the sheet-engaging notch is removed from said path, means responsive to the leading edgeof a sheet passing a given point in said path for actuating said clutch to connect said roll to said drive, and a stationary paper stop adjacent said roll and intersecting the circular plane defined by the periphery thereof to be engaged by the edge of the sheet carried by said roll and disengage the edge from said notch, said sheet stop positioned at a. point sufiiciently removed from said path that when the leading edge of a sheet is removed from said notch the trailing edge of the sheet has been fed to the discharge point by said conveyin means so that the sheet is turned over when deposited on the stack.

5. A sheet-feeding and stacking apparatus according to claim 4 characterized by the fact that the linear speed of the sheet-conveying means is faster; than the linear speed of the periphery of the pick-up roll whereby said conveying means acts to force the leading edge of a sheet into the bottom of the notch on the roll when the-latter isv in the path .of the sheets and the trailing edge of the sheet gripped by said notch reaches the discharge point of said conveying means at substantially the same time the leading edge of the sheet engaging said paper stop and is removed by the notch thereby.

6. In a sheet-feeding and stacking apparatus the combination with means for conveying individual flexible sheets separately and in a flatwise condition along a given'path to a discharge point above the plane in which the sheets are to be stacked and comprising an endless horizontally arranged feed belt on the upper reach of which the sheets are adapted to be placed flatwise, means for advancing said belt at a given linear speed, a second endless guiding belt horizontally arranged above said feed belt with its lower reach substantially in contact with the upper reach of said feed belt for holding said sheets flat on said feed belt, means for feeding said guide belt in the same direction and at the same linear speed as said feed belt, a generally circular sheet pick-up roll rotatably mounted beyond the end of said feed belt so that the circular portion of its periphery is substantially tangent to the horizontal plane of upper reach of said feed belt, a raised portion on the periphery of said roller provided with a sheet-engaging.

notch, the open end of which is adapted to lie in the path of and receive the leading end of a sheet advanced by said belt when the roller is in an operative position, means for rotating said roller in the same direction as the movement of said sheets to move the notch into a sheet-engaging position and then carrying the leading end of the sheet downwardly and away from said given path, said last-mentioned means including a single revolution clutch acting to normally hold the pick-up roll in an inoperative position and upon actuation allowing the roll a single revolution through its operative position and back to its inoperative position, means responsive to the leading edge of a sheet passing a given point in said path for actuating said clutch to set said roll in motion, and a stationary sheet stop lying adjacent and intercepting the plane defined by the periphery of said roll for engaging and removing the leading edge of the sheet from the notch in said roll at substantially the instant the trailing edge of said sheet leaves the end of said conveying means.

7. A sheet-feeding and stacking apparatus according to claim 6, characterized by the fact that said means responsive to the leading edge of said sheet passing a given point in said path for actuating said clutch includes a solenoid which actuates the clutch when energized, means for directing a light beam across the path of said sheets, a photocell on the other side of said path for picking up said light beam, and means electrically connected with said photocell for momentarily connecting said solenoid to a power source when said light beam is out 01f from said photocell.

'8. A sheet-feeding and stacking apparatus according to claim 6, characterized by the fact that the drives for the feed belt and pick-up roll have a relation such that the linear speed of the feed belt is faster than the linear speed of the roll whereby the feed belt will force the leading edge of a sheet into said notch in the roll and the trailing edge of a sheet gripped by said roll will be fed along said path faster than the leading edge is drawn therefrom to efiect the desired turnover of the sheet.

RICHARD N. FULLER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name I Date 867,424 Scott Oct. 1, 1907 991,002 Miehle May 2, 1911 2,572,472 Griflin Oct. 23, 1951

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