US3737160A

US3737160A - Document stacker system

Info

Publication number: US3737160A
Application number: US00159216A
Authority: US
Inventors: W Monday
Original assignee: Recognition Equipment Inc
Current assignee: Recognition Equipment Inc
Priority date: 1971-07-02
Filing date: 1971-07-02
Publication date: 1973-06-05
Anticipated expiration: 1990-06-05

Abstract

The specification discloses a document stacker system which may accommodate various sizes of documents which flow at a variable frequency. The stacker system includes a rest station which includes a set of fingers upstanding in the path of travel of incoming documents in order to arrest the movement of the documents. Springs urge the documents downward to engage the fingers. Cans are disposed between the fingers to periodically raise the end of the document arrested by the fingers above the fingers. A pair of resilient rollers are synchronized with the cams to contact the top and bottom surfaces of the document raised by the cams. A transport then receives the document from the pair of rollers for delivery to various stacker receptacles. Each stacker receptacle includes a paddle which is movable vertically within the receptacle for supporting a document stack. A motor is operable to drive the paddle to a desired level within a receptacle in accordance with the sensed height of the document stack within the receptacle. A one-way clutch prevents downward movement of the paddle unless positive drive is provided from the motor, such that the operation of the paddle is substantially independent of the weight of the documents thereupon.

Description

United States Patent 1 Monday 1 June 5,1973

[54] DOCUMENT STACKER SYSTEM [75] Inventor: William C. Monday, Garland, Tex.

[73] Assignee: Recognitioh Equipment, Incorporated, Irving, Tex.

[22] Filed: July 2, 1971 [21] App1.No.: 159,216

[52] US. Cl. ..27l/64, 271/53, 271/88 [51] Int. Cl. ..B65h 29/60 [58] Field of Search ..271/53, 60, 64, 86, 271/88, 35; 214/6 DK [56] 7 References Cited UNITED STATES PATENTS 3,086,772 4/1963 Vogel ..27l/6O X 3,633,903 1/1972 Foster ..27l/88 X Primary Examiner-Richard E. Aegerter Assistant ExaminerJohnny D. Cherry Attorney-Richards, Harris & Hubbard [57] ABSTRACT The specification discloses a document stacker system which may accommodate various sizes of documents which flow at a variable frequency. The stacker system includes a rest station which includes a set of fingers upstanding in the path of travel of incoming documents in order to arrest the movement of the documents. Springs urge the documents downward to engage the fingers. Cans are disposed between the fingers to periodically raise the end of the document arrested by the fingers above the fingers. A pair of resilient rollers are synchronized with the cams to contact the top and bottom surfaces of the document raised by the cams. A transport then receives the document from the pair of rollers for delivery to various stacker receptacles. Each stacker receptacle includes a paddle which is movable vertically within the receptacle for supporting a document stack. A motor is operable to drive the paddle to a desired level within a receptacle in accordance with the sensed height of the document stack within the receptacle. A one-way clutch prevents downward movement of the paddle unless positive drive is provided from the motor, such that the operation of the paddle is substantially independent of the weight of the documents thereupon.

16 Claims, 13 Drawing Figures PAIENTEDJuu SISTS 3.737.160

SHEET 10F 7 INVENTORZ WILL IAM C. MONDAY ATTORNEYS PATENTEDJUH 5 I915 SHEET 2 BF 7 INVENTOR. WILLIAM C. MONDAY ATTORNEYS PATENTED H 5 I97 SHEET 3 [IF 7 INVENTOR: WILLIAM C. MONDAY ATTORNEYS PATENTEUJUH 5l973 SHEET 5 OF 7 FIG. 6

INVENTOR: WILLIAM C. MONDAY ATTORNEYS PATENIEDJUH 5|975 3.737.160 SHEET GDP 7 FIG. 7

g INVENTOR:

, WILLIAM C. MONDAY ATTORNEYS PATENTEDJUN 51975 SHEET 7 BF 7 FIG. 8

INVENTORZ WILL IAM C. MONDAY ATTOR NE YS 1 DOCUMENT STACKER SYSTEM FIELD OF THE INVENTION THE PRIOR ART Various document processing systems, and in particular automatic optical character recognition systems, have been developed to process documents of varying size and paper character. For example, 8-% X 11 inch typewritten sheets may comprise input data to a character recognition system in which each document is to be read line by line, in which case the document feed rate through the system would be relatively slow. However, the document feed rate of a character recognition system would be relatively fast when the input data comprises credit card documents wherein a single line only is to be read. Document stacking systems for character recognition systems have heretofore been provided which have varied widely depending upon the desired application, but which have often not been satisfactory with respect to flexibility in acceptance of various document sizes and in acceptance of document feed rates which widely vary.

The present invention is directed particularly to a document stacker capable of accommodating documents of wide variance in size and flow rates, and at the same time capable of handling relatively stiff cardboard documents as well as more flexible sheet materials.

SUMMARY OF THE INVENTION In accordance with the present invention, capability for handling and stacking varied documents at varied demand rates are provided. A transport moves documents along a path of travel. A plurality of spaced apart abutment fingers are upstanding in the path of travel of the documents for arresting the movement of the documents at a predetermined location. Cams are disposed between ones of the abutment fingers for periodically raising the end of a document above the abutment fingers. Roller members are synchronized with the cams for contacting the raised end of the document and for feeding the document to the next station fol-stacking.

In accordance with another aspect of the invention, a document transport is provided for delivery of documents to a stacker, wherein the documents may vary in size and flow at a variable frequency. The transport includes an input surface having at least one moving belt along which each document is fed. Air flow is directed upon the input surface to force each document against the belt to move the document at belt speed. A set of fingers are upstanding in the path of travel of the documents fed from the belt. Springs urge the documents downwardly to engage the fingers. A pair of resilient rollers are adapted to contact top and bottom surfaces of the document arrested by the fingers. Cams are synchronized with the pair or rollers to raise the end of the documents above the fingers. A transport receives the documents from the pair of rollers for delivery to the stacker.

In accordance with another aspect of the invention, a stacker system is provided wherein documents of varying sizes may be accommodated. At least one stacking receptacle is provided for the documents and includes a paddle support which is movable vertically within the receptacle to support a document stack. A motor is operable to drive the paddle support to a desired level within the receptacle in accordance with the height of the document stack. A constant force spring biases the paddle support in an upward position. A oneway drive prevents downward movement of the paddle support unless positive drive 'is provided from the motor.

DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present application, and for other objects and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a layout of an optical reading system including the document stacker of the present invention;

FIG. 2 is a somewhat diagrammatic representation of a document transport, reading and stacker system;

FIG. 3 is a perspective view of the reststation for use with the present stacker; 7

FIGS. 4a-c are side views of various positions of the rest station of the present invention;

FIG. 5 is a side view of the present stacker unit;

FIG. 6 is a top view of the present stacker unit;

FIG. 7 is another side view of the present stacker unit;

FIG. 8 is a top view of the one-way drive for use with the paddle drive system of the invention;

FIG. 9 is a partially sectioned view of the drive shown in FIG. 8;

FIG. 10 is a sectional view taken section lines 10-10 in FIG. 9; and

FIG. 11 is an end view of the splined shaft shown in FIG. 9.

The present document stacker system may be best understood by reference to its relation to a complete document reading system. Referringto FIG. 1, a page processor 10 is employed for the feeding, scanning and stacking of documents. The page processor comprises a feeder unit 11, a transport scanning unit 12 and a I one-way generally along the stacking unit 13 to which the present invention is directed. Peripheral equipment-to the system comprises a control console 14, an I/O unit 15, a peripheral control unit 16, a recognition unit 17 which includes logic circuitry for the recognition of characters of fixed fonts as well as characters of handprint execution, a line printer 18 and a tape transport unit 19.

The system shown in FIG. 1 has the capability of accepting 9 X 14 inch documents with single spaced full coverage of the document. The system is capable of reading and completely transferring to storage, to line printer 18 or tape transport 19 all ofthe information on such documents at rates of the order of about thirty pages per minute. On the other hand, credit card type documents, wherein the reading is to be accomplished on one or two lines only, can be processed by the present system at the rate of up to 300 cards per minute. The system operates by placing into a hopper in feeder 11 a stack of documents to be read, feeding the documents one at a time into the'tape transport and scanning unit 12, and then delivering the documents to the stacking unit 13 wherein the stacking can be selectively dependent upon any coded information on the documents themselves.

In order to provide an understanding of the setting in which the present invention finds itself and the desirability for the unique capabilities of the stacker of the present invention, the line diagram of FIG. 2 will be described.

Referring now to FIG. 2, a document feeder 11 has been illustrated as comprising a tray in which a stack D of documents may be placed with the documents being oriented as to stand on the bottom edge thereof. A paddle 31 is slidably mounted to move the documents forward against a shuttleplate unit 32. The paddle 31 is linked mechanically as by linkage 33 to a chain 34 which is servo driven to maintain the documents in a given density in the region of the face of the shuttleplate unit 32. A shuttleplate 35 is reciprocated through a crank unit 36 on a shaft 37 driven by a feeder motor 38 through a single revolution clutch 38a. The shuttleplate 35 has a plurality of apertures formed through it. A vacuum is maintained in the apertures through a vacuum system connected to an exhaust pipe 39. By this means, individual documents are sequentially removed from the stack D and are moved downwardly into engagement with a set of pinch rollers that are diagrammatically represented at 40.

The pinch rollers 40 direct each document into the document transport scanning unit 12 wherein the document is advanced by a belt that is driven by a pair of

servo motors

51 and 52 in response to a position encoder 53 and a suitable control system. Documents are maintained in contact with the belt 50 by a series of rollers 54 as well as by jets of air that are directed downwardly from

parallel tubes

55 and 56 positioned above and on opposite sides of the belt 50. In the region of arc 60, the documents are drawn into a fixed position against a bedplate by a plurality of vacuum ports (not shown). Are 60 represents the scan location of documents traveling under the action of the belt 50, and the arrow 59 represents the direction of travel of the documents.

At the scan location, light from a high intensity lamp 62 passes through a lens system 63 onto an oscillating mirror 64 and is projected and focused onto a scan point on are 60. The mirror 64 is mounted on a shaft 65 that is driven by a servo motor 66 having a servo tachometer 67 associated therewith and an encoder 68 responsive to the movement of the shaft 65. A scanning mirror 70 is mounted on the shaft 65 for oscillation with the mirror 64. Light reflected from the mirror 70 passes through a lens system 71 onto a columnar retina 72. In one embodiment of the system, the retina 72 is provided with ninety-six active cells and is operated such that characters viewed by the retina as the light beam sweeps are 60 actually fall on or energize sixteen cells for a normal character, i.e., a character of usual type print height. The remainder of the cells of the retina are employed in the system for locating the next line to be scanned and for providing control signals to the

servo motors

51 and 52, whereby the document is properly positioned for the initiation of the scan of the next line.

Once scanned, each document is fed to a rest station 13a at the input of the stacker unit 13. The movement of the document is arrested at the rest station to permit the stacker unit to respond to control instructions. Then in accordance with such control instructions, the document is delivered, either to a selected one of three bins a, 80b, and 80c, or to a reject bin 80d. The

movement of documents in the stacker unit 13 is under the control of

stacker gates

81, 82 and 83, and spiral stacking wheels are employed to deliver documents to the

selectable bins

80a, 80b, and 800.

In order to accommodate documents of different weights, a positive control is provided through a stacker motor 86 operating through

clutches

88a, 88b, and 88c to maintain the top of the stack of the documents on each of the paddles 80ac, respectively, in a predetermined relation to the periphery of the spiral stacking wheels. In each bin, the document level is sensed by photocells to control the respective clutches 88a-c.

Within this environment, the document stacker 13 of the present invention is called upon to provide reliable feed and stacking of documents to the system in each of the many various conditions that may be prescribed by a user. The system of FIGS. 1 and 2 thus may operate in a wide variety of conditions and thus may be termed a universal document reader, being limited only by the maximum size of documents that can be accommodated in the document transport and stacking systerns.

Photoelectric sensors 89, not shown, are disposed adjacent the paddles 80ac and control the operation of the stacker motor 86. The paddles 80a-c are respectively slidably mounted upon shafts 9011-0 and are moved along the shafts 90a-c by operation of suitable belts or chains 92a-c. Chains 92ac are reaved over pulleys 94a-c and 96a-c. Each of the chains 92a-c is respectively coupled through negators spring 98a-c, with the end of each of the constant force springs being connected to a rigid frame. Operation of the stacker motor 86 may then move the chains 92ac to move the paddles 80a'c vertically along the shafts 9011-0, in order to maintain the stack of documents thereon in a predetermined relationship to stacking wheels 100a-c. Wheels 100a-c serve to decelerate and stack documents fed from the rest station 13a. For further description of the control of deflecting blades for selective stacking of documents with a plurality of pockets, reference is made to U. S. Pat. No. 3,460,673, issued on Aug. 12, 1969, to the present assignee.

FIG. 3 illustrates in perspective detail the construction of the rest station 130. A plate supports a first set of abutment fingers I 12 which include a plurality of spaced apart fingers with abutment portions 114 upstanding in the path of travel of documents fed to the system. Plate 110 also supports a second set of abutment fingers 116 which comprises a plurality of spaced apart fingers-with abutment portions 118 also upstanding in the path of travel of the documents. The set of abutment fingers 112 in the preferred embodiment comprises a larger number of spaced apart fingers than does the set of abutment fingers 116. The number and spacing of abutment members on the two sets of fingers differs to prevent canted documents from sticking or otherwise lodging between the fingers. The belt, not shown, which delivers the documents to the rest station 13a are slightly canted a few degrees to provide positive control of the documents fed to the station.

A support 120 is attached to a pair of spring supports 122 and 124. Spring support 122 supports a plurality of resilient spring fingers 126 which tend to prevent documents from slipping over the upstanding abutment portions 114. Likewise, a set of resilient spring fingers 128 is connected to support 124 and exerts a downward bias to aid in preventing documents from slipping over the upstanding abutment portions 118. A shaft 130 supports a first set of spaced apart cams 132 and a second set of spaced apart cams 134. Cams 132 are spaced between each of the abutment fingers 112, while cams 134 are disposed between each of the abutment fingers 116.

Shaft 130 also supports a pair of spaced apart pincher

rollers

136 and 138. A belt 140 rotates the pincher rollers and the

cams

132 and 134 in synchronism. An upper pair of

pincher rollers

142 and 144 are mounted for rotation about a shaft 146. Rotation of the

rollers

142 and 144 operates a drive belt 148. The

pincher rollers

136, 138, 142 and 144 include raised portions which are adapted to engage upper and lower portions of a document which have been raised above the

upstanding abutment portions

114 and 118 by the

cams

132 and 134. The pincher rollers then move the document to a stacker unit for stacking upon a selected one of the paddles 80a-c.

FIGS. 4a-c best illustrate the operation of the rest station 130. As shown in FIG. 4a, a document D is transported by suitable belts in the manner previously described until the movement of the document is arrested by the upstanding abutment portions 114. The stopping of the movement of the document D enables the control operations of the stacker to be synchronized for stacking of documents of various sizes and flow rates. In the position illustrated in FIG. 4a, the spring fingers 126 urge document D downwardly against the fingers 112.

As shown in FIG. 4b, cams 132 rotate between the fingers 112 and come into contact with the document D in such a manner as to raise the edge of the document D up above the abutment portions 114. As best shown in FIG. 4c, the projecting portions of the

pincher rollers

138 and 144 then engage upper and lower portions of the document D and move the document with some force to the selected stacker bin in the direction of the arrow 149.

Referring to FIG. 5, a side view of the stacker unit 13 is illustrated. The documents are fed from left to right, and initially come to rest at the rest station 13a. Pressurized air is supplied via an air supply pipe 150 through suitable apertures in order to apply pressurized air downwardly upon the documents. A vacuum is also applied via members, not shown, to the underside of the documents in order to hold the documents firmly against the transport belt. The documents are brought to rest at the rest station 13a in the manner previously described and then fed to the stacker 13 for reception by a selected one of the stacker wheels 100a-c.

The stacker wheels each comprise a plurality of spaced apart spiral elements such that a document is received between the elements and gently moved downwardly for stacking upon one of the paddles 80a-c. As previously described, the paddles 80a-c are respectively mounted for vertical movement along the shafts 90a-c. Pressurized air is applied through vents l52a c in order to fluff up the documents stacked upon the paddles. Belt 148 is driven by the stacker motor in order to rotate the pincher rollers in the manner previously described. Suitably driven belts deliver the documents to the one of the stacker wheels 100a-c which has been selected by control of the stacker blades 82 and 84 as previously described.

FIG. 6 illustrates in detail the top view of the stacker unit 13. Pressurized air is applied through the air inlet pipe and is applied downwardly through air nozzles and air pipes in order to force the documents against the transportation belts. A guide member 162 serves to guide the documents into place at the rest station 13a. Support 122 supports the first set of spring fingers 126, while support 124 supports the second set of spring fingers 128 in the manner previously described. The belt 148 is driven by the

pincher rollers

144 and 142 as previously described. A motor, not shown, rotates a belt 164 which rotates a shaft 166 which provides rotating motion to the pincher rollers. A brush bracket 168 supports a brush and roller 170 which extends into engagement with the documents in order to positively feed the documents through the pincher rollers.

The stacker paddle operation may be best understood by referring to FIGS. 6 and 7. As shown in FIG. 7, a stacker motor 86 is mounted on the side of the system and applies drive through a gear box 180. A toothed belt 182 is driven from the gear box and drives

toothed belts

184 and 186. Drive from the motor 86 is also applied through a belt 188 which applies drive through a gear box 190 and through the clutch 88a for operation of the chain 92a. Chain 92a operates the paddle 80a in the manner'shown in FIG. 2. The constant force spring 98a is connected between the system frame and the chain 92a, as previously described. A blower 192 supplies pressurized air for the air fluffer mechanism and also for application to the documents and drive belts.

Drive is also applied through belt 184 to a toothed belt 194 which applies drive through a gear box 196 to the'clutch 88a. Drive is provided through the clutch 88b to a chain 92b to move the paddle 80b as previously described. The constant force spring 98b is connected between the system frame and chain 92b. Drive is applied through belt 186 to a belt 202 which provides drive through a gear box 204 to the clutch 88c. Drive is provided through the clutch 880 to the chain 920 for movement of the paddle 800. Spring 980 is connected between the chain 92c and the system frame.

Blower 200 supplies pressured air to the document feeder. Blower 208 provides the vacuum for the feeder operation.

FIGS. 8-11 illustrate in greater detail the construction of the one-way clutches 88a-c. Drive is transmitted through a gear box 190 to a shaft 250 which extends into the end of a body 252. As best shown in FIGS. 8 and 9, shaft 250 includes an outwardly projecting knob 254 which extends through a slot 256 in the body 252. The slot 256 is canted so that rotation of the shaft 250 will cause the body 252 to be moved with respect to the longitudinal. axis of the shaft 250. A counterbored housing 258 is connected to body 252 and includes a one-way clutch and bearing 260 which rotatably receives an end of a shaft 262. As shown in FIGS. 9 and 10, the counterbore portion of housing 258 includes a plurality of cylindrical holes 264 therein. The end of the shaft 262 includes a plurality of projections 266 which are adapted to mate with the holes 264 to act as a spline. A pulley 280 is mounted on the end of shaft 262 and may be operated to rotate the chain 92a.

In operation of the one-way clutch mechanism, if the paddle 80a is unloaded, the spring 98a exerts an upward force on the tooth belt 92a to maintain the paddle 80a at its upper position. If a relatively light stack of documents is provided on the paddle 80a and the photoelectric sensing device determines that the height of the stack is excessive, motor 86 is energized and the shaft 250 is rotated. The knob 254 rolls along the slot 256 and earns the body 252 into contact with the projections 266 of shaft 262. Shaft 262 is then rotated in order to move the chain 92a in order to move paddle 80a downward into the desired position.

If an extremely heavy load is upon the paddle 80a, the weight of the document stack tends to rotate the pulley 280 and the shaft 262 even if the motor 86 has not been energized. A slight rotation on the shaft 262, however, causes the projections 266 to become disengaged from the holes 264. Substantial downward movement of the paddle 80a then is prevented by the oneway clutch 260. When the motor 86 is energized, the shaft 250 cams the housing 252 into engagement with the end of the projections 266 on shaft 262 in order to positively drive the shaft 262. Thus, it will be seen that the one-way clutch of the invention enables heavy document loads to be held back until the proper document stack height is reached, and yet enables the paddle to be driven down under relatively light loads of documents.

The present stacker is thus capable of handling documents ranging from a relatively small size, in the range of 3- /1 inches by 4% inches, to larger sizes of up to 9 inches by 14 inches, with a minimum of required machine setting changes. The present stacker accepts documents of varying sizes from a transport at random and at varying speeds, without a required direct connection with an optical reader system. The present constant speed stacker, in conjunction with the rest station as described, enables design simplicity while providing excellent stacking characteristics for documents of varying sizes and at varying feed rates. The present stacker paddle configuration enables positive control of a document stack, regardless of the document stack weight.

Whereas the present invention has been described with respect to specific embodiments thereof, it will be understood that various changes and modifications will be suggested to one skilled in the art, and it is intended to encompass such changes and modifications as fall within the scope of the appended claims.

What is claimed is:

1. A document transport system comprising:

means for moving documents along a path of travel,

a plurality of spaced apart abutment members upstanding in the path of travel for arresting the movement of the documents at a predetermined location,

cams disposed between said abutment members for periodically raising the end of a document above said abutment members, and

upper and lower resilient roller members synchronized with said cams and having mating raised portions for contacting the raised end of the document and for feeding the document to the next station.

2. The transport system of claim 1 wherein said abutment members comprise fingers extending generally parallel to the path of travel of the documents and including abutment end portions upstanding in the path of travel.

3. The transport system of claim 2 wherein said cams rotate between said fingers and include cam portions which periodically move above said abutment end portions.

4. The transport system of claim 1 and further comprising: spring means for urging documents against said abutment members.

5. A document transport for delivery of documents to a stacker where the documents may vary in size and flow at a variable frequency which comprises:

an input surface having at least one moving belt along which each document is fed,

means to direct air flow upon said input surface to force each document against said belt to move the document at belt speed,

a set of fingers upstanding in the path of travel of documents fed from said belt,

springs for urging documents downward to engage said fingers,

a pair of resilient roller means adapted to contact top and bottom surfaces of the document arrested by said fingers,

cam means synchronized with said pair of roller means to raise the end of the document above said fingers, and

transport means to receive documents from said pair of roller means for delivery to said stacker.

6. The document transport of claim 5 wherein said fingers are positioned in two spaced apart groups, said roller meansbeing disposed between said groups.

7. The document transport of claim 6 wherein said cam means are interposed between adjacent fingers ments from said transport means,

means for selectively directing documents into one of said receptacles, and means in said receptacles for maintaining the height of the documents stacked therein at a predetermined level.

10. The document transport of claim 9 wherein said means for maintaining the height of documents comprises:

a support paddle for supporting a stack of documents,

means for sensing the level of the stack of documents on said support paddle, and

means for vertically moving said paddle in response to said sensing means.

11. The document transport of claim 10 wherein said moving means comprises:

motor driven belt means connected to said paddle,

and

an electrical clutch responsive to said sensing means for transmitting drive to said belt means. 12. The document transport of claim 11 and further comprising:

constant force spring means attached to said belt means to exert an upward force-on said paddle,

one-way drive means including a splined shaft rotatably journaled in a housing, said shaft operable to drive said belt means, and

an output shaft from said electric clutch connected to cam said housing to and from contact with the end of said splined shaft, whereby said paddle may be accurately driven to a desired level regardless of the weight of the stack of documents thereon.

13. In a stacker system wherein documents of varying sizes must be accommodated, the combination comprising:

a stacking receptacle for said documents including a paddle support which is movable vertically within said receptacle for supporting a document stack,

motor means operable to drive said paddle support to a desired level within said receptacle in accordance with the height of said document stack,

spring means for biasing said paddle support in an upward direction, and

one-way clutch means interconnecting said motor means and said paddle support for preventing downward movement of said paddle support unless drive is provided from said motor means.

14. The combination of claim 13 wherein said oneway drive means comprises:

a drive shaft having a splined end and connected to drive said paddle support at the other end,

a housing for rotatably receiving said splined end of said drive shaft, said housing including a corresponding splined portion, and w an output shaft from said motor means extending into said housing and including a lateral cam projection extending through a canted groove within said housing, whereby said drive shaft is operable to move said paddle support downwardly only when said motor output shaft is rotated to cam said housing such that said splined end is mated with said splined portion of said housing.

15. The combination of claim 14 and further comprising:

a flexible drive linkage moved by rotation of said drive shaft to move said paddle support, said negator spring means connected to said drive linkage for biasing said paddle support upwardly.

16. The combination of claim 13 and further comprising:

means for sensing the height of said document stack,

and

means operable by said sensing means for applying drive from said motor means.

Claims

1. A document transport system comprising: means for moving documents along a path of travel, a plurality of spaced apart abutment members upstanding in the path of travel for arresting the movement of the documents at a predetermined location, cams disposed between said abutment members for periodically raising the end of a document above said abutment members, and upper and lower resilient roller members synchronized with said cams and having mating raised portions for contacting the raised end of the document and for feeding the document to the next station.

5. A document transport for delivery of documents to a stacker where the documents may vary in size and flow at a variable frequency which comprises: an input surface having at least one moving belt along which each document is fed, means to direct air flow upon said input surface to force each document against said belt to move the document at belt speed, a set of fingers upstanding in the path of travel of documents fed from said belt, springs for urging documents downward to engage said fingers, a pair of resilient roller means adapted to contact top and bottom surfaces of the document arrested by said fingers, cam means synchronized with said pair of roller means to raise the end of the document above said fingers, and transport means to receive documents from said pair of roller means for delivery to said stacker.

6. The document transport of claim 5 wherein said fingers are positioned in two spaced apart groups, said roller means being disposed between said groups.

7. The document transport of claim 6 wherein said cam means are interposed between adjacent fingers and are rotated at a constant speed.

8. The document transport of claim 5 wherein said roller means contacts the top and bottom surfaces of a document only when said document is raised by said cam means.

9. The document transport of claim 5 and further comprising: a plurality of stacking receptacles for receiving documents from said transport means, means for selectively directing documents into one of said receptacles, and means in said receptacles for maintaining the height of the documents stacked therein at a predetermined level.

10. The document transport of claim 9 wherein said means for maintaining the height of documents comprises: a support paddle for supporting a stack of documents, means for sensing the level of the stack of documents on said support paddle, and mEans for vertically moving said paddle in response to said sensing means.

11. The document transport of claim 10 wherein said moving means comprises: motor driven belt means connected to said paddle, and an electrical clutch responsive to said sensing means for transmitting drive to said belt means.

12. The document transport of claim 11 and further comprising: constant force spring means attached to said belt means to exert an upward force on said paddle, one-way drive means including a splined shaft rotatably journaled in a housing, said shaft operable to drive said belt means, and an output shaft from said electric clutch connected to cam said housing to and from contact with the end of said splined shaft, whereby said paddle may be accurately driven to a desired level regardless of the weight of the stack of documents thereon.

13. In a stacker system wherein documents of varying sizes must be accommodated, the combination comprising: a stacking receptacle for said documents including a paddle support which is movable vertically within said receptacle for supporting a document stack, motor means operable to drive said paddle support to a desired level within said receptacle in accordance with the height of said document stack, spring means for biasing said paddle support in an upward direction, and one-way clutch means interconnecting said motor means and said paddle support for preventing downward movement of said paddle support unless drive is provided from said motor means.

14. The combination of claim 13 wherein said one-way drive means comprises: a drive shaft having a splined end and connected to drive said paddle support at the other end, a housing for rotatably receiving said splined end of said drive shaft, said housing including a corresponding splined portion, and an output shaft from said motor means extending into said housing and including a lateral cam projection extending through a canted groove within said housing, whereby said drive shaft is operable to move said paddle support downwardly only when said motor output shaft is rotated to cam said housing such that said splined end is mated with said splined portion of said housing.

15. The combination of claim 14 and further comprising: a flexible drive linkage moved by rotation of said drive shaft to move said paddle support, said negator spring means connected to said drive linkage for biasing said paddle support upwardly.

16. The combination of claim 13 and further comprising: means for sensing the height of said document stack, and means operable by said sensing means for applying drive from said motor means.