US3485489A

US3485489A - Document feeding mechanism

Info

Publication number: US3485489A
Application number: US669457A
Authority: US
Inventors: Everet F Lindquist
Original assignee: MEASUREMENT RESEARCH CENTER IN
Current assignee: MEASUREMENT RESEARCH CENTER IN; MEASUREMENT RESEARCH CENTER Inc; National Computer Systems Inc
Priority date: 1967-09-21
Filing date: 1967-09-21
Publication date: 1969-12-23
Anticipated expiration: 1986-12-23

Description

Dec. 23, 1969 E. F. LINDQUIST DOCUMENT FEEDING MECHANISM 4 Sheets-Sheet 1 Filed Sept. 21. 1967 FIG! 96 so 93 ii:

H E-l INVENTOR EVERET F. LINDQUIST MIMM ATTORNEYS Dec. 23, 1969 F. LINDQUIST 3,

DOCUMENT FEEDING MECHANISM Filed Sept. 21. 1967 4 Sheets-Sheet 2 FIGS i\\\ \1' L\\\-.: i/

so a a2 32 INVENTOR FIG 5 EVERET F. LINDOUIST ATTORNEYS Dec. 23. 1969 F. LINDQUIST 3,

DOCUMENT FEEDING MECHANISM Filed Sept. 21, 1967 4 Sheets-Sheet 5 INVENTOR EVERET F. LINDQUIST M,WF'W

ATTORNEYS Dec. 23, 1969 F. LINDQUIST 3,48

DOCUMENT FEEDING MECHANISM Filed Sept. 21, 196'? 4 Sheets-Sheet 4.

I"IIWIJIIHIIIIIIIWHIIwill! i a,

INVENTOR EVERET E LINDQUIST FIG IO ATTORNEY! United States Patent U.S. Cl. 271--6 23 Claims ABSTRACT OF THE DISCLOSURE An apparatus for feeding successive documents edgewise from a stack of documents by use of a tractor assembly including a flexible belt mounted on a pair of pulleys and positioned so that a portion of one run of the belt between the pulleys overlies the leading-edge surface of the end document to be fed, with the remainder of ther un extending over a support surface over which the documents are fed. The end of the tractor overlying the stack of documents is movable toward and away from the stack to pivot the belt into and out of position to engage and feed a document from the stack.

This invention relates to feeding mechanisms, and more particularly to an improved mechanism for feeding of documents one-at-a-time in edge alignment from an input stack despite random variations in the size, weight, thickness, or surface characteristics of the documents fed.

The increase in use of electronic and mechanical data processing equipment such as computers, electronic scanning devices, automatic counting mechanisms, and the like, has resulted in the development of a large number of document or sheet feeding devices used in association with this equipment. These known document feeding devices have generally been designed for a specific use, or use with a specific type of data processing machine, and have not been readily adaptable for universal use. While the feeder of the present invention is particularly well suited for feeding documents in edge alignment oneat-a-time to a document scanning device, it is equally well suited for use in numerous other applications where it is desired to transport documents at selected velocities and frequencies.

It is the principal object of the present invention to provide an improved high speed feeding apparatus for feeding documents one-at-a-tirne from the end of a stack of documents.

Another object is to provide such a feeder in which the successive documents are fed from the stack in precise edge alignment.

Another object is to provide such a feeder which will reliably feed documents one-at-a-time despite random variations in the dimensions, weights, thicknesses, and surface characteristics of the documents fed.

Another object is to provide such a feeder which will reliably feed documents one-at-a-time from a stack in which various types and sizes of documents, including multiple page booklets, damaged or wrinkled sheets, or the like, are randomly intermixed within the stack.

It is another object to provide such a feeder which will reliably feed documents either continuously or on demand, as desired.

Another object is to provide such a feeder in which the documents may be fed either from the top or bottom of a stack, whether the stack be vertical, horizontal, inclined, or fanned out in an overlapping row.

The foregoing and other objects are attained in a feeder including a hopper for holding and supplying a stack of documents to be fed and for advancing the end document of a stack of documents to a feeding position in the hopper. A tractor assembly consisting of a flexible belt positioned over a pair of pulleys is mounted so that a portion of one run of the belt overlies the leading-edge surface of the end document to be fed from the hopper. The end of the tractor overlying the hopper is movable toward and away from the hopper to thereby move the belt into or out of engagement with the end document in the stack so that the belt may be continuously driven, yet operable to feed one or more sheets from the stack on command.

A platform projecting outwardly from the feed position of the hopper provides a supporting surface over which the documents are fed by the tractor assembly, and a suitable retard area is provided on the platform to resist movement of the document over the surface. The coefficient of friction between the tractor belt and the documents to be fed is greater than that between the documents and the retard surface so that the belt can readily slide the documents over the retard area. However, the coefficient of friction between the documents and the retard area is greater than that between two documents so that a second document will be retained by the retard area and the documents will be fed one-at-a-tirne even with the tractor continuously retained in the feeding position.

A guide surface is provided along one side of the hopper and along the feed platform, and the document feeding mechanism resiliently urges the individual documents into side-edge contact with the guide surface to thereby feed the documents in precise edge alignment.

Other objects and advantages of the invention will become apparent from the following description, taken with the drawings, in which:

FIG. 1 is a fragmentary side elevation view of a feeding apparatus embodying the invention;

FIG. 2 is a top plan view of the apparatus shown in FIG. 1;

FIG. 3 is an enlarged fragmentary view of a portion of the mechanism shown in FIG. 2;

FIG. 4 is a fragmentary sectional view further illustrating the tractor mechanism shown in FIG. 3;

FIG. 5 is an levation view, in section, taken along line 5-5 of FIG. 3;

FIG. 6 is a view similar to FIG. 5 and illustrating an alternate embodiment of the invention;

FIG. 7 is a sectional view of the tractor belt, taken on line 7-7 of FIG. 6;

FIG. 8 is a view similar to FIG. 6, and showing a further embodiment of the invention;

FIG. 9 is a fragmentary bottom plan view of a portion of the mechanism shown in FIG. 8; and

FIG. 10 is a fragmentary sectional view illustrating a further embodiment of the invention.

Referring now to the drawings in detail, a feeding mechanism according to the present invention is indicated generally by the reference numeral 10 and includes a hopper 11 for receiving and supporting a stack of documents 12 to be fed by the apparatus. The hopper 11 has a vertically movable bottom platform 13 supported by an elongated piston 14 telescopingly received in a fluid cylinder 15. A segment of a vertical wall 16 of the apparatus frame structure forms one side wall of the hopper, and a second vertically extending frame member 17 forms an end wall of the hopper. Member 17 carries an obstruction plate 18 on its upper edge, with the straight upper edge 19 of the plate 18 defining the feed position of documents 12 from the open top of hopper 11.

A buckling inhibitor plate 20 is positioned on the end document 12 of the stack on platform 13 to prevent buckling and wrinkling of the documents during the high acceleration of a document fed from the hopper. Plate 20 is preferably formed of a relatively light weight, rigid, low friction material such as a sheet of plastic, and has one side edge extending closely adjacent the inner guide surface .21 of Wall 16. Plate is pivotally connected to one end of a connecting arm 22 which, in turn, is rigidly connected to a pin 23 rotatably supported by wall 16. Thus, plate 20 is free to move vertically with a stack of documents in contact with the end document in the stack.

A rotary fluid valve 24 is mounted on wall 16 and projects outwardly therefrom above the stack of documents 12. A sensing arm 25 is fixed on the end of the shaft 26 of valve 24, and a roller 27 is supported on the end of arm 25 in position to engage the end document 12 in the stack of documents in the hopper. Shaft 26 is resiliently biased in a direction to maintain the roller 27 in contact with the document. Fluid under pressure is supplied to the valve 24 through an inlet conduit 28, and rotation of the valve shaft 26 in a counterclockwise direction, as viewed in FIG. 1, results in fluid being directed from the valve through a conduit 29 to the fluid cylinder 15 to thereby raise the level of the stack of documents 12 and thereby simultaneously rotate the shaft 26 in a clockwise direction to return valve 24 to the null position. Thus, valve 24 and fluid cylinder 15 cooperate to maintain the end document 12 in the hopper 11 in a feeding position spaced slightly above the upper edge 19 of obstruction plate 18.

Documents 12 fed from the hopper 11 are transported over a horizontal platform 30 extending outwardly from and in alignment with the upper edge 19 of obstruction plate 18. A rectangular opening 32 is formed in platform 20 adjacent the hopper end wall 17, and a pair of

rollers

33, 34 are mounted for rotation about parallel axes on the lower surface of platform 30, with the

rollers

33, 34 projecting upwardly into the opening 32. A third roller 35 is mounted on wall 16 at a point spaced below

rollers

33, 34 and a retard belt 36 is mounted for rotation about an endless path over these three rollers. As best seen in FIG. 5, the thickness of belt 36 is preferably such that its outer surface projects slightly above the platform 30, with a portion of the belt 36 and platform 30 cooperating to define a document supporting surface 31. Thus, documents being fed over the surface 31 are in surface contact with the belt 36. The coefficient of friction between the outer surface of belt 36 and a document is substantially greater than that between the document and the platform 30 so that the belt tends to retard or restrict movement of the documents over the surface 31. The belt 36 is driven in the direction of arrow 37 and its speed is preferably variable to thereby vary the resistance of movement of documents over platform 30.

A pair of hold-down

shoes

38, 39 have one end supported by a bracket 40 which, in turn, is pivotally supported by a shaft 41 mounted on wall 16 above hopper 11. The

shoes

38, 39 have their other ends disposed above and gravity biased toward the belt 36 so that a document 12 moving along surface 31 will be retained in positive contact with the retard surface of the belt 36. Preferably, the retard belt is spaced slightly in the feed direction, i.e., the direction of movement of documents from the hopper, to permit a document being fed from hopper 11 to drag an underlying document over edge 19 for a short distance before the underlying document engages the belt 36.

A tractor assembly is mounted on the wall 16 and overlies a portion of the platform 30, including retard belt 36, and extends above a portion of the open top of hopper 11. Tractor 50 comprises a shaft 51 mounted for rotation in a journal 52 about an axis substantially perpendicular to the wall 16. Suitable means such as motor 53 is provided to drive the shaft in a clockwise direction as viewed in FIGS. 1, 5, 6, and 8. A tractor frame 54 is rotatably mounted on shaft 51, as by spaced journal blocks 55, 56 of a rigid forked frame member 57. An arm 58 of frame member 57 has a recess 59 formed therein to provide spaced opposed mounting tabs or

brackets

60, 60a. A second frame member 61 has a mounting bracket 62 formed on one end thereof, with the bracket 62 being clamped between

tabs

60, 60a, as by set screw 63. A pair of spaced

arms

64, 65 formed on frame member 61 have opposed

elongated slots

66, 67 respectively, formed therein to support a shaft 68. A pin, or set screw 69 mounted in arm 64 extends through shaft 68 to locate one end of the shaft 68 centrally within slot 66 and to prevent rotation of the shaft. A set screw 73 is mounted in a threaded opening in arm 65 in position to engage the other end of shaft 68, and is adjustable to vary the position of the shaft 68 within slot 67 to thereby vary the alignment of shaft 68 with respect to shaft 51. 'Further, the frame member 61 may be adjusted with respect to the frame member 56 by the set screw 63 to further vary the alignment of the

shafts

68 and 51 with respect to one another.

A first pulley 70 is mounted between

journals

55, 56 on shaft 51 for rotation therewith, and a second pulley 71 is mounted between

arms

64, 65 on shaft 68 for free rotation thereon. An endless belt 72 is mounted on the

pulleys

70, 71 for rotation therearound upon rotation of the shaft 51 and pulley 70 by the motor 53. A first pair of

guide rollers

75, 76 are mounted one on journal block 55 and the other an journal block 56 on the side thereof opposite arm 58 and in position to engage the side edges of the belt 72 to retain the belt on pulley 70. A similar set of rollers 77, 7 8 are mounted one on each of the

arms

64, 65 in position to engage and retain the belt 72 on the pulley 71.

As illustrated in FIGS. 25, frame member 61 is mounted on frame member 57 to position the pulley 71 outwardly from wall 16 a distance greater than the pulley 70, and to misalign the shaft 68 with respect to the shaft 51 so that the bottom run of the belt 72 is disposed at a slightly converging angle with respect to the wall 16 in the feed direction of the apparatus. This results in

pulleys

70 and 71 being misaligned with respect to one another, so that belt 72 will tend to run off the pulleys. To assist in retaining the belt on the pulleys, a shaft 80 is mounted on frame member 57, as by screw 81, and a pair of

rollers

82, 83 are mounted thereon in position to engage the side edge of the belt 72. Also, a rigid support bracket 84 mounted on frame member 61, supports a roller bracket 85, which in turn, supports a guide roller 86 in position to engage the side edge of the belt 72 adjacent the roller 71 to further assure that the belt 72 follows the desired path around the rollers.

Belt 72 is formed from a relatively soft, resilient rubbery material having a very high coefiicient of friction with paper. Preferably, the outer face of belt 72 is made up of a plurality of parallel longitudinally extending strips 88 formed by providing a series of grooves 87 in the belt as shown in FIG. 7. These strips 86 are easily deflected transversely of belt 72 and therefore serve to limit the force which may be exerted on a document by the belt in the direction of guide surface 21. Also, belt 72 is flexible, and may deflect as a unit to further limit this force which might otherwise tend to buckle a thin, flexible document against the guide surface 21. Further, belt 72 extends closely adjacent to the guide surface 21 so that the natural resistance to budkling of relatively thin documents such as single sheets of bond paper will be great enough to cause the sheet to slide transversely beneath the belt.

A solenoid 90 is pivotally mounted, as by pin 91, on the wall 16 and the movable core of the solenoid is pivotally connected, as by connecting rod 92 and pin 93, to the rigid support bracket 84. The solenoid is operable to pivot the tractor assembly about the axis of shaft 51 between a lower feeding position illustrated in FIG. 1 and a raised, non-feeding position illustrated in FIGS. 5, 6 and 8. In the lower or feeding position, the bottom run of the belt 72 is in position to engage the end document in a stack of documents in the hopper and the document supporting surface 31. Belt 72 is both resilient and flexible and, therefore, is deflected upward slightly by the retard surface of the belt 36 when the tractor is in the feed position. In the raised position, the belt 72 preferably re mains in contact with the surface 31 for a short distance immediately beneath the pulley 70, but is spaced slightly above the surface 31, including the retard belt 36, and the end document in the hopper throughout the remainder of the length of the tractor assembly.

A pair of driven pinch rolls 95, 96 are mounted on wall 16 adjacent the end of tractor 50 with roll 95 being mounted below, and roll 96 being mounted above the platform 30. The

rolls

95, 96 have their surfaces in contact with one another through an opening 97 in the platform 30 so that a document 12 fed beneath the tractor 50 passes between the

rolls

95, 96 and is positively fed thereby from beneath tractor 50.

Rolls

95, 96 may be driven directly from motor 53, as by belt 98.

As illustrated in the drawings, the

rolls

95, 96 may feed the individual documents beneath an electronic scanning head illustrated schematically by the reference numeral 100. Additional feed roll pairs 101 may be provided, as necessary, to deliver the documents from the scanner to a suitable receptacle.

It is noted that the wall 16 extends from the hopper 11 along one side edge of the platform 30, and the inner surface 21 of this wall 16 provides an edge guide reference for the documents fed by the device.

In operation of the feeder described above, a stack of documents 12 are carefully jogged to align one side edge of the documents as nearly as is practicable, and the stack is then placed in the hopper 11 with the aligned edge in contact with the guide surface 21 of the wall 16. The buckling inhibtor plate is positioned on top of the stack and the sensing roll 27 is positioned in engagement with the uppermost, or end document 12 in the stack. Valve 24 then directs pressure fluid to the fluid cylinder 15 to raise platform 13 as necessary to position the end document 12 in the feeding position at the open top of the hopper 11, with the end document spaced slightly above the top edge 19 of the obstruction plate 18. Solenoid 90 may then be energized to move the tractor 50 to the feeding position so that belt 72 (which is continuously driven by motor 53) engages a portion of the top surface of the end document to feed the document along the surface 31. Since belt 72 is positioned at a converging angle with respect to the guide surface 21 of wall 16, the document being fed will be urged ino side edge engagement with he surface 21 so that the individual documents are fed in precise edge alignment.

As a document moves over surface 31, it passes beneath the

shoes

38, 39 which urge the document into contact with the retard surface of the belt 36. Since the coefficient of friction between the document and the belt 72 is greater than that between the document and the belt 36, the document will continue to be fed by the tractor belt 72. However, any subsequent documents tending to be dragged along surface 31 by the end document will also engage the retard belt 36 and, since the coefiicient of friction between the belt 36 and the documents is greater than that between two documents, these subsequent documents will be retarded by the belt 36 and only the end document will be fed by the belt 72.

As the leading edge of the end document passes into the nip of pinch rolls 95, 96, solenoid 90 may be deenergized to move the tractor to the non-feed position so that subsequent documents are not fed by the continuously driven belt 72. If desired, the pinch rolls 95, 96 may be driven at a speed greater than the belt 72 to accelerate a document as it is fed from the tractor.

Energization of the solenoid 90 may be controlled by the random command of a computer, or other suitable device, or by a human operator, or it may be cyclically controlled by a mechanical or electrical device, to feed documents on demand from the hopper. Alternatively, the tractor may be left in the feed position continuously or for a predetermined length of time to feed a succession of documents from the hopper. When documents are fed in succession, there may be a tendency for the documents to merge from beneath the tractor assembly in slightly overlapping relation. However, by driving the pinch rolls 95, 96 at a rate slightly greater than the speed of the tractor belt 72 the documents may be accelerated to provide any desired spacing between successive documents, within limits.

Referring now to FIG. 6, an alternate embodiment of the invention is disclosed in which the retard belt 36 is replaced with a resilient block insert 136 mounted on platform 30. Block 136 projects slightly above and cooperates with the upper surface of the platform 30 to define the document supporting surface 131. Also, a roll is mounted on the wall 16 and projects upwardly through an opening 111 in platform 30 and engages the belt 72 of tractor assembly 50 directly beneath the pulley 70. This roll 110 minimizes the frictional drag between a document and the surface 131 of platform 30 after the document has passed over the retard surface of block 136.

In the FIG. 6 embodiment, the tractor assembly may be moved to the non-feed position as soon as the leading edge of a document passes over the roll 110, with the document continuing to be fed by the contact of the belt ith the document immediately above the roll 110. If desired, the roll 110 may be driven, and may be provided with a relatively high friction surface to assure that a document positioned between the roll and belt 72 will be pulled over the retard surface 136 beneath the

shoes

38 and 39.

A further embodiment of the invention is shown in FIGS. 8 and 9 in which the tractor belt 72 is mounted for movement in a path parallel to the inner surface of wall 16. In this embodiment the individual documents are .urged into edge registry with the inner guide surface 21 of wall 16 by the roller which engages the belt 72 beneath the pulley 70 through an opening 121 in platform 30. The roller 120 is mounted for rotation about an axis inclined slightly with respect to the wall 16 so that a document moving through the feeder will be urged toward the wall 16. Roller 120 is rotatably supported by a U-shaped bracket 122 mounted on the upper flange 123 of a right angle bracket 124. The bracket 124 is supported on wall 16 by a pair of bolts 125 extending through an elongated slot 126 so that the bracket may be adjusted vertically along wall 16 toward and away from the tractor assembly. Further, the bracket 122 is supported on flange 123 by a single bolt 127 so that the bracket 122 may be adjusted to vary the angle of the roller 120 with respect to the wall 16. Thus, the roller .120 may be adjusted to vary the force exerted on the documents by the roller in the direction of the guide surface of wall 16, as well as to vary the degree of frictional contact between the roller 120 and the belt 72.

Referring now to the embodiment of the invention illustrated in FIG. 10, an alternate structure for positioning the top, or end document in a stack of documents at the feeding position will be described in detail. A stack height sensing and control valve is pivotally supported on the vertical wall 16, as by pin 141. Valve 140 comprises a fluid cylinder 142 having a free-floating pis ton 143 slidably mounted therein with an annular recess 144 formed around its outer periphery to permit a flow of air from the single inlet 145 outwardly through the two outlets 146, 147. The outlet ports of the valve are positioned so that, with the piston 143 in its normal centered or balanced position, air flowing into the valve through inlet port 145 will be divided with equal amounts flowing outward through ports 146 and 147.

A first fluid conduit 148 is connected to the outlet port 146 of control valve 140 for directing fluid through an inlet port 149, to the rod end 150 of a fluid cylinder 151. A second conduit 152 is connected to outlet port 147 for directing fluid therefrom through an inlet port 153 to the head end 154 of the fluid cylinder 151. A small 7 orifice 155 is formed in the conduit 148, and a similar orifice 156 formed in the conduit 152. A piston 157 Within the cylinder 151 is connected to a rod 158 which, in turn, supports the vertically movable bottom platform 13 of the hopper 11.

A bracket 159 is rigidly mounted on the vertical plate 16, and a leaf spring assembly 160 is mounted, as by bolts 161, on the bracket 159. The leaf springs 160 are inclined downwardly and engage the uppermost document 12 to exert a downward compressive force on a stack of documents in the hopper 11. Preferably, the spring assembly 160 extends outwardly from the hopper in overlying relation with the retard belt 36 and a portion of the platform 30 to urge a document being fed along the document supporting surface 31 into frictional contact with the retard surface of the belt 36. A stack height adjustment screw 162 is mount-ed on the end of the piston 143 for movement therewith, with the lower end of the screw 162 resting on the spring 160 to sense the height of the spring and thereby the height of the uppermost document in the hopper. Screw 162 moves vertically with spring 160 and thereby positions the piston 143 to vary the flow of air flowing to the head and rod ends of fluid cylinder 151.

In operation of this embodiment, a constant flow of air is directed to valve 140 through inlet port 144 and outwardly therefrom through ports 146 and 147. This air builds up pressure on both the head and rod ends of the fluid cylinder 151 and thereafter is bled out through the orifices 155 and 156. The differential area between the head and rod end of the piston 157 will cause the piston to move upwardly to elevate the stack of documents 12 against the force of the leaf spring 160 to compress the stack of documents in the hopper. Initially the piston 143 of valve 140 will be positioned to direct a greater flow of air through outlet 147 to thereby increase the pressure in the head end 154 of cylinder 151. However, as the leaf spring 160 is deflected upward, the piston 143 will be moved upward until a balanced condition is reached, in which balanced condition the uppermost document in the hopper will be in the feeding position. This balanced condition is maintained very stable by bleeding air from the

lines

148, 152 so that hunting of the system is eliminated.

The stack-height adjustment mechanism shown in FIG. 10, and described above, is particularly useful in feeding documents such as data sheets, booklets, or the like, which have been handled individually and which have been mutilated by wrinkling, folding, embossed by pencil marking, etc. Such documents do not lay smooth and flat when placed in a stack, but rather tend to exhibit a phenomenon which can be described as sponginess. Because of the non-fiat condition of the documents, and the air entrapped between successive documents, pressure on the top of the stack exerted, for example, by a fraction feeding device, such as the feeding belt of the tractor assembly of this invention, will cause the stack to compress and decrease in height. The amount of compression, for a given pressure on the top of the stack, varies with the number of documents in the stack and the condition of the individual documents, with the consequence that the friction between the feeding device and the document fed will vary depending on the height of the stack of documents in the hopper. With a stack of several thousand individaul sheets in the hopper, this sponginess may result in conventional friction feeding devices being ineffective to feed a document from the stack. Conversely, if sufficient force is applied to feed the individual documents when sponginess is at a maximum, then the friction may be so great as to result in the feeding of more than one document when the stack is near depletion. This condition is effectively avoided by the above described stack-height adjustment control which maintains a constant compressive force on the uppermost document in the stack, regardless of the height of the stack of documents in the hopper.

A document feeding apparatus according to the present invention is capable of feeding sheets at any desired frequency (up to 100,000 per hour, or more, for certain types of material) on command, as in feeding punched tabulating cards by computer control. Further, the velocity at which the individual documents are transported may readily be controlled so that substantial flexibility, both in the time separation between documents and the amount of data read from each document, is obtainable.

Since there are no fixed throat separators employed in the feeder, and further since the tractor belt 72 is resilient, documents of varying thicknesses, including folded booklets, leaflets, or the like, may be fed by the device either from a stack of such booklets or intermixed with single sheets, cards, or the like. Also, since the belt 72 engages the documents closely adjacent one side edge of the document to be fed, documents of varying sizes, weights, thicknesses, and surface characteristics such as standard tabulating cards, bond paper, semi-flexible cardboard, or the like, may be intermixed in the stack being fed.

Because of the frictional drag between the end document and a subsequent document, and further because of the force couple caused by the inertia of the top document resisting the acceleration by the tractor belt engaging the document at the side edge thereof, the trailing edge of a document being fed is automatically forced toward the guide surface 21 of the wall 16. As the document progresses through the feeder, the angled belt, or angled roller, urges the leading edge into contact with the side guide so that each sheet passes from the feeder in precise side edge registry. Any tendency of the documents to buckle against the guide surface 21 is resisted, first by the buckling inhibitor plate 20, and subsequently by the resiliency of the belt 72. Since belt 72 is mounted in close proximity to guide surface 21, relatively thin documents such as single sheets of bond paper may be fed in precise side registry without the documents being buckled by the apparatus.

While the feeding device has been illustrated and described as feeding documents from the top end of a vetrical stack of documents, it is believed apparent that the device could be employed with equal facility to feed documents from the top or bottom end of the stack, whether the stack be vertical, horizontal, inclined, or fanned out in an overlapping row. Further, while the device has been illustrated as feeding the documents from a conventional hopper, it is believed apparent that a moving :belt or other means could readily be employed to deliver the documents to a feed position. Accordingly, while I have disclosed and described preferred embodiments of my invention, I wish it understood that I do not intend to be restircted solely thereto, but that I do intend to cover all embodiments thereof which would be apparent to one skilled in the art and which come within the spirit and scope of my invention.

I claim:

1. An apparatus for feeding successive documents edgewise from a supply of documents comprising means for advancing the documents from a supply to a feeding position, a platform adjacent said feeding position and extending outwardly therefrom providing a fixed supporting surface over which successive documents from said supply are conveyed, said supporting surface including a high friction retard means adjacent said feeding position, tractor means for engaging a document in said feeding position and feeding said document onto said supporting surface, said tractor means including a first pulley mounted for rotation about an axis overlying a document in said feeding position, a second pulley mounted for rotation about a fixed axis overlying said supporting surface, an endless belt mounted on said pulleys for movement about an endless path defined by said pulleys, said endless path including one run extending in a plane between said first and second pulleys, said one run being disposed adjacent to and overlying a portion of a document in said feeding position and a portion of said supporting surface including said retard means, means for moving said first pulley toward and away from said feeding position between a first position in which said one run of said belt is disposed substantially parallel to said support surface and positioned to engage a portion of said support surface and an exposed surface of a document in said feeding position and a second position in which said one run is disposed at an angle with respect to said supporting surface, said one run in said second position being positioned to engage said supporting surface only adjacent said second pulley and in spaced relation to a document in said feeding position, and means for driving said belt around said endless path to feed documents one at a time from said feeding position over said supporting surface, said belt being effective to continue feeding a document from beneath said second pulley when said first pulley is in said second position.

2. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 1, wherein a document being fed by said belt is resiliently urged into engagement with said supporting surface and said retard means by said belt only when said first pulley is in said first position.

3. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 2, wherein said belt has a high friction surface with the coefficient of friction between said high friction surface and the documents fed thereby being greater than the coefficient of friction between the documents and said retard means.

4. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 3, wherein the coeflicient of friction between said retard means and a document fed thereover is greater than the coefiicient of friction between two such documents.

5. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 2, further comprising a side guide extending along said platform and said feeding position at one side thereof providing a fixed reference guide for one side edge of documents fed from said feeding position, and aligning means for resiliently urging one side edge of documents into engagement with said side guide as the document is fed from said feeding position by said belt.

6. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 5, wherein said aligning means comprises a roller extending through said supporting surface and normally engaging said belt adjacent said second pulley, and means mounting said roller for rotation about an axis slightly divergent from a true perpendicular with respect to the plane of said side guide, said roller and said belt cooperating to resiliently urge a document passing therebetween into engagement with said guide.

7. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 6, further including means mounting said roller for adjustment to vary the angle between said roller axis and the plane of said side guide.

8. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 2, wherein said high friction retard means comprises resilient means mounted on said platform and projecting slightly outwardly therefrom to form a portion of said support surface.

9. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 2, wherein said high friction retard means comprises an opening formed in said platform adjacent said feeding position, a retard element, mounting means supporting said retard element on said platform adjacent said opening, said retard element having a high friction surface projecting through said opening and forming a portion of said support surface.

10. An apparatus for feeding succesive documents edgewise from a supply of documents as defined in claim 9, wherein said retard element is a driven element, said high friction retard means further comprising means for driving said retard element to move said high friction surface in a direction to resist movement of a document from said feeding position by said belt.

11. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 10, wherein said retard element is driven belt, and wherein said mounting means supporting said retard element comprises a plurality of pulleys rotatably mounted on said platform.

12. An apparatus for feeding successive documents edgewise from a supply of documents comprising, power means for advancing the documents from said supply to a feeding position, a platform adjacent said feeding position and extending outwardly therefrom providing a supporting surface over which documents from said supply of documents are conveyed, said supporting surface in cluding high friction retard means adjacent said feeding position, a first pulley mounted for rotation about an axis overlying a document in said feeding position, a second pulley mounted for rotation about an axis overlying said supporting surface, an endless belt mounted on said pulleys, means for moving said first pulley toward and away from said feeding position between a first position in which said belt is positioned to engage an exposed surface of a document in said feeding position and a second position in which said belt is spaced from a document in said feeding position, means for driving said belt around an endless path over said pulleys to feed documents oneat-a-time from said feeding position over said supporting surface, said endless path including a segment extending along and overlying at least a portion of a document in said feeding position and a portion of said supporting surface including said retard surface and resiliently urging a document being fed by said belt into engagement with said supporting surface when said first pulley is in said first position, and retard shoe means adjacent said belt and biased toward said retard means for continuously urging a document disposed therebetween into engagement with said retard means and said supporting surface.

13. An apparatus for feeding successive documents edgewise from a supply of documents comprising, power means for advancing the documents from said supply to a feeding position, a platform adjacent said feeding position and extending outwardly therefrom providing a supporting surface over which documents from said supply of documents are conveyed, said supporting surface including high friction retard means adjacent said feeding position, a first pulley mounted for rotation about an axis overlying a document in said feeding position, a second pulley mounted for rotation about an axis overlying said supporting surface, an endless belt mounted on said pulleys, means for moving said first pulley toward and away from said feeding position between a first position in which said belt is positioned to engage an exposed surface of a document in said feeding position and a second position in which said belt is spaced from a document in said feeding position, means for driving said belt around an endless path over said pulleys to feed documents one-at-a-time from said feeding position over said supporting surface, said endless path including a segment extending along and overlying at least a portion of a document in said feeding position and a portion of said supporting surface including said retard surface, and resiliently urging a document being fed by said belt from said stack into engagement with said supporting surface and said retard means when said first pulley is in said first position, a side guide extending along said platform and said feeding position at one side thereof providing a fixed reference guide for one side edge of a document being fed from said feeding position, and means mounting said first and said second pulleys to position said segment of said endless path in spaced, slightly convergent relation to said side guide in the direction from said feeding position to urge documents being moved along said supporting surface by said belt into engagement with said side guide.

14. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 13, further including means mounting one of said pulleys for adjustment to permit the angle between said side guide and said segment of said endless path to be varied to thereby vary the force imparted to a document by said belt in the direction of said side guide.

15. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 14, wherein said belt has a plurality of closely spaced parallel grooves formed in and extending longitudinally around said high friction surface of said belt to permit lateral deflection of said outer surface to thereby limit the force exerted on a document in the direction of said side guide.

16. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 13, further comprising a pair of pinch rolls mounted in position to receive a document fed from said supply by said belt, and means for driving said rolls to positively feed a document received therebetween by said belt.

17. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 16, wherein said pinch rolls are driven at a linear surface spaced greater than the linear speed of said belt to thereby accelerate a document delivered thereto by said belt.

18. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 16, wherein said means for moving said first pulley is operable to move said first pulley to said first position to feed a document from said feeding position and to said second position when the document is engaged by said pinch rolls.

19. An apparatus for feeding successive documents edgewise from a supply of doucments as defined in claim 13, further comprising hopper means for supporting said supply of doucments in a stack and a feed opening in said hopper, said power means including means for advancing the stack of documents in said hopper to position the endmost document in the stack in a feeding position adjacent said opening in said hopper.

20. An apparatus for feeding successive documents edgewise from a supply of documents as defined in claim 19, wherein said hopper further comprises a movable platform for supporting said stack of documents, said power means comprises a fluid piston and cylinder means supporting said platform for movement toward and away 12 from said opening, sensing means for sensing the presence of a document at said feeding station, and means responsive to said sensing means for directing fluid under pressure to said fluid piston and cylinder means.

21. In a document feeding apparatus for feeding successive documents edgewise from a supply of documents including means for advancing the documents from said supply to a feeding position, a platform adjacent said feeding position and extending outwardly therefrom providing a supporting surface over which documents from said supply of documents are conveyed, and conveyer means for feeding said documents from said feeding position one-at-a-time from said feeding position onto said supporting surface, the improvement wherein said conveyer means comprises a tractor assembly including a first pulley, means mounting said first pulley for rotation about a fixed axis overlying said supporting surface, frame means mounted for pivotal movement about said fixed axis and extending therefrom to overlie a portion of said feeding position, a second pulley rotatably mounted on said frame in overlying relation to said feeding position, endless belt means mounted on said first and second pulleys for movement therearound in an endless path, means driving said belt around said endless path, and means pivotally moving aid frame about said fixed axis to move said belt toward and away from said feeding position.

22. In a document feeding apparatus as defined in claim 21, the further improvement wherein said means driving said belt includes motor means driving said first pulley for rotation about said fixed axis.

23. In a document feeding apparatus as defined in claim 22, the further improvement wherein said means pivotally moving said frame includes solenoid means selectively operable to move said frame between a feed ing position and a retracted position.

References Cited UNITED STATES PATENTS 252,477 l/ 1882 Kneeland 27149 664,340 12/1900 Sturtevant 271-34 3,108,801 10/1963 Dalen 27134 X 3,198,514 8/1965 Barbera 27l--34 X OTHER REFERENCES IBM Bulletin, vol. 4, No. 2, July 1961.

EDWARD A. SROKA, Primary Examiner US. Cl. X.R. 27l34, 49