US3027161A

US3027161A - Sheet feeder

Info

Publication number: US3027161A
Application number: US781729A
Authority: US
Inventors: Erik R Solyst
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1958-12-19
Filing date: 1958-12-19
Publication date: 1962-03-27
Anticipated expiration: 1979-03-27
Also published as: GB909982A; FR1246415A; GB909983A; DE1254158B

Description

March 27, 1962 E. R. soLYsT 3,027,161

SHEET FEEDER Filed Deo. 19, 1958 5 Sheets-Sheet l ATTORNEY E. R. SOLYST SHEET FEEDER March 27, 1962 5 Sheets-Sheet 2 INVENTOR ERIK R. SOLYST ATTORNEY Filed Deo.

March 27, 1962 E. R. SOLYST 3,027,161

SHEET FEEDER Filed Deo. 19, 1958 5 Sheets-Sheet 3 INVENTOR. |08

ERIK R. SOLYST ATTORNEY March 27, 1962 E. R. soLYsT SHEET FEEDER Sheets-Sheet 4 Filed DeC. 19, 1958 INVENTOR.

ERIK R SOLYST JQ/Je ATTORNEY March 27, 1962 E. R. soLYsT 3,027,161

SHEET FEEDER Filed Dec. 19, 1958 5 Sheets-Sheet 5 States arent 3,027,161 SHEET FEEDER Erik R. Solyst, Havertown, Pa., assigner to Eurroughs Corporation, Detroit, Mich., a corporation of Michigan Filed Dec. 19, 1958, Ser. No. 731,729 18 Claims. (Cl. 271 1t}) The invention relates generally to improvements in machines for handling sheet material and more particularly to apparatus for advancing a stack of sheets to a transfer station and means at the transfer station for separating the sheets from the stack and forwarding the separated sheets to a delivery point. While the invention is capable f a variety of uses in the sheet feeding art, it finds special application in mechanized banking operations, as for example, in sorting machines for feeding various size documents such as checks, punch cards and the like in sorting or other operations.

An object of the invention is to provide a novel sheet stack advancing mechanism.

Another object of the invention is to provide improved means for feeding sheets one at a time from a stack of such items.

A further object of the invention is to provide an improved sheet stack advancing mechanism for eihcient and reliable handling of stacks of intermixed sheets of various sizes.

A still further object of the invention is to provide a sheet feeding apparatus with means providing for precise control of starting and stopping of the apparatus.

Another object of the invention is -to provide means whereby an operator may quickly restore a jammed machine to operating condition.

In accordance with the above objects and rst considered in its broad aspects, the invention comprises a sheet feeding mechanism for handling stacks of sheets or documents, such as bank checks, of the same or of different sizes. The mechanism includes a support for the stack and a plurality of pusher devices for advancing the stack along the support to a feeding station where the sheets are separated from the stack and forwarded to their destination. In guarding against the possible event of a sheet jam, means are provided for simple and rapid manipulation of the apparatus, for quick removal `of the sheets causing the jam.

The invention will be more fully revealed in the following detailed description of a specific embodiment thereof when read in conjunction with the accompanying drawings in which:

FIG. 1 is a vertical sectional view of the apparatus of FIG. 3 taken along line 1 1 and omitting certain parts to more clearly reveal other parts;

FIG. 2 illustrates a stack of intermiXed sheets of various ,sizes with some of the sheets disposed in diiferent regions of the stack;

FIG. 3 is a view taken in the direction of arrows 3 3 of FIG. l;

FIG. 4 is a sectional view of a sheet forwarding roller and associated sheet guide mechanism, taken along line 4 4 of FIG. 3;

FIG. 5 is a sectional view taken along line 5 5 of FIG. 4 and illustrating further the sheet guide mechanism in open or retracted position for relieving a sheet jam;

FIG. 6 is a sectional view of a locking device for the sheet guide mechanism taken along line 6 6 of FIG. 3;

FIG. 7 is a view taken along line 7 7 of FIG. 6;

FIG. 8 is a sectional view of a one-way clutch device taken along line 8 8 of FIG. l;

FIG. 9 is a sectional view taken along line 9 9 of FIG. l and illustrating magnetic clutch and brake devices of the drive mechanism for controlling rotation of the sheet feeding belt;

FIGS. 10 and 11 illustrate open and closed positions respectively of a sheet retarding belt;

FIGS. 12 and 13 illustrate a sheet separating action of the retarding belt;

FIG. 14 is a sectional View taken along line 14-14 of FIG. 3 and showing the sheet stack pusher carriages and the drive means therefor; and,

FIG. l5 is another view of the stack pusher carriages and their drive means taken along line 15 1S of FIG. 14.

As illustrated in the drawings, the preferred form of the invention comprises a stack hopper and multiple stack pushers adapted for advancing either aligned or unaligned stacks of intermixed sheets of various sizes along the hopper to a sheet feeding belt. An aligned stack is defined as one which has been previously conditioned so that an edge of the sheets Will bear against a hopper member, or side plate as it is referred to hereinafter, while an unaligned stack is one in which the sheets are randomly disposed in the stack with some of the sheets hanging up in the stack so that they are not bearing against the side plate. In the latter case, the sheets which do not bear against the side plate create a loose area at the lower region of the stack so that ordinarily it would be diflicult to feed sheets from 'the stack because of the danger of their buckling and becoming damaged.

'Ihe stack pushers are arranged for relative movement to compensate `for the loose area of the stack whereby the stack is compressed at this region so that the leading or end sheet of the stack will at all times be presented rmly along its length to the sheet feeding belt and with the proper degree of force.

The sheet feeding belt is so placed relative to the sheet stack that it will at all times contact the leading sheet in the stack regardless of its size or disposition within the stack, and thus assure that the sheets will be separated from the stack in proper sequence. plished by having a portion of the belt operate preferably in the least common area of the intermixed sheets, however, if desired the belt may be arranged to operate above the least common area.

In order to guard against a possible multiple feed wherein two or more sheets may adhere together and be fed simultaneously from the sheet stack, means are provided by a novel arrangement and action of a retarding belt whereby the multiple sheets are separated one from another and allowed to be fed forwardly in proper sequence.

The apparatus may be employed either for flow feeding or intermittent feeding and in either such case the individual sheets are spaced one from another as they are forwarded to their destination.

In the case of a jam wherein one or more sheets may become lodged in the apparatus, convenient linkage means are provided whereby the operator may retract portions of the apparatus to relieve the machine of the jam and rapidly restore the machine to operating condition in the least possible time.

Turning now to the drawings, wherein there is illustrated the preferred form of apparatus constructed in accordance with the invention, a sheet stack hopper 1i) (FIGS. l and 3) comprises a table 11 and an upwardly extending side plate 12 secured along a portion of the lower edge of table 11. As shown in FIG. 14, table 11 is secured to a base plate 13 fastened to a frame 14 of an associated apparatus, such as, for example, a sorting machine.

Secured to base plate 13 and extending perpendicular thereto is a stud 15 (FIG. 14) for securing a feeding head 16 which mounts an endless sheet feeding belt 17 (FIG. 3). Feeding head 16 comprises a frame 18 hav- This is accom-` ing a hub 19 (FIGS. 1 and 3) and a lateral extension 20. Extension 20 is formed with a bore and is received thereby and secured on stud 15 by means of a nut 21 threadedly engaging the end of the stud. A drive down roller or pulley 22 formed with a circular groove 23 is secured on a sleeve 24 mounted for rotation in hub 19 by means of anti-friction bearings and retained axially in hub 19 by means of retaining rings 27 and 28. A shaft 25 extends into sleeve 24 and is drivingly coupled to the sleeve by means of key portions 26 engaging a slot in the end of the sleeve.

Secured to an extended portion of hub 19 (FIG. l) is a bearing block 29 formed with a rectangular cavity 30 extending inwardly from one end and terminating in a fiat bottom 31. A grooved roller 32 is rotatably mounted on a pin 33 secured to a rectangular plunger 34 slidably received in cavity 30. Plunger 34 is formed with a short projecting portion 35 on which is centered one end of a compressing spring l36, the other end of the spring being received in a counterbore 37 extending inwardly of the bottom 31 and centered on the head of a screw 38 secured to block 29. Block 29 is slotted through its left and right sides to provide for mounting of roller 32 which extends through the slot (FIG. 3). The endless sheet feeding belt 17 has a friction driving surface and is mounted in the grooves of rollers 22 and 32.l and maintained in constant tension by the biasing action of compression spring 36. Rotatably mounted on three pins 39 fixed to frame 18 are rollers 40 (FIG. 3) which serve to maintain the feeding portion of belt 17l in a planar condition adjacent a sheet stackV S. A sheet metal guard 41 (see also FIG. 14) secured to frame 18 encloses a substantial portion of the feeding head 16 and includes a slotted wall portion 42 extending downwardly at a spaced distance from the sheet stack S to terminate in a deector portion 43 (FIG. 3).

The sheet feeding apparatus thus described will effectively feed sheets frorn the stack one at a time in a manner more fully described hereinafter, however, in the event of a multiple feed, provision is made for separating the sheets and feeding them forwardly in proper sequence. For such purpose, there is provided an endless sheet retarding belt 44 (FIGS. 3, l() and ll) normally in contact with an arcuate portion of drive down roller 22 and having a friction sheet retarding surface. Belt 44 may be stationary during operation but in order to distribute wear it is preferable to rotate it in one direction or the other. For such purpose, there is provided a reduction gear drive, not shown, but contained in a housing 45, and operated from shaft 25 (FlG. l) by means of a belt 47, the shaft 25 being rotated by a motor 46 in a manner to be more fully explained hereinafter.

The drive is transmitted to the retarding belt 44 by means of two

shafts

48 and 49 coupled to the reduction gearing and on which are securely mounted two drive rollers 50 and 51 respectively, of friction material. The retarding belt 44 is yieldably pressed against drive down roller 22 by means of spring pressed

rollers

52, 53 and 54, (FIGS. and ll). The rollers are similarly mounted so a description of one of the mountings will suffice. Roller 52 for example, is disposed between two spaced parallel bell crank levers 55 and 56 (see also FIG. 1) and rotatably mounted on a pin 57 whose ends respectively are secured to

arms

58 and 59 of

levers

55 and 56, the Vlevers being pivotally mounted on a pin 60 secured to housing'45. The lower arms 61 and 62 of

levers

55 and 56 respectively are secured together in spaced relation by means of a pin 63 to which is attached one end of a tension spring 64, the other end of the spring being secured` to a pin 65 fixed to housing 45. A lever 66 is pivotally mounted at one end on pin 60 and has secured adjacent its other end a finger grip knob 67 having a shank portion 68 projecting through the lever and disposed in the path of movement of the lower end of lever arm 61. A tension spring 69 secured at one end to a pin 70 fixed to lever arm 61 and at the other end to a pin 71 fixed to lever 66 serves to maintain the shank portion 68 against the end of lever arrn 61.

As mentioned above,

rollers

53 and 54 are similarly mounted as roller 52 and each is accordingly mounted on a pair of spaced levers similarly biased by `a spring 64, with one of the levers having an arm disposed in the path of movement of shank 68 in a manner similar to arm 61.

A bracket 72 is secured to housing 45 and is formed with an elongated slot 73 extending therethrough in which is disposed a pin 74 secured to the end of lever 66. A latch 75 is pivotally mounted on a pin 76 secured to housing 45 and is biased in a counterclockwise direction by means of a helical spring 77 having one end engaged in slot 73 and the other end pressing against a pin 78 secured to latch 75, the pin 78 being of sufficient length to engage an edge 79 of bracket 72 which limits its movement.

As seen in FIG. ll, the retarding belt 44 passes around

rollers

50, 51 and 52, and then about

rollers

80 and 81 mounted on pins 6() and 76 respectively, and then about a roller 8 2 which is mounted on a lever 83 pivoted at 84 to housing 45 and then about an idler roller 85. Lever 83 is biased in a counterclockwise direction by means of a tension spring 86 having one end secured thereto at 87 and` the other end secured on a pin 88 fixed to housing 45. The tension spring 86 thus serves to take up slack in the retarding belt 44.

If for any reason it is required toV retract the retarding belt 44 from the drive down roller 22, as for example, in the. event of a sheet jam, this is accomplished by manually pulling. knob 67 to rock the roller. levers clockwise on pin 60 from the position of FIG. 11 to the position of FIG. l0 until pin 7.4 rides over a cam surface 89 on latch 75y and is caught in the hook of the latch thus to hold the retarding belt 44 in open position. To release the retarding belt for closed operating position, latch 75 is released manually by pressing on a|- finger grip knob 99 secured thereto until pin 74 is free of the hook at which point the tension springs 64 willl bias the levers counterclockwise and the retarding belt 44 into closed operating position.

Before proceeding with the operation of the above described sheet feeding apparatus, it is important to note that When the apparatus is used for separating sheets from an intermixed stack of various sizes, it is preferable to have roller 321 (FI-G. 3) so placed relative to the sheet stack that the upper portion of the sheet feeding belt 17 will operate within the least common area of the different size sheets. FIG. 2 illustrates a sheet stack. having different size sheets wherein sheet S1 represents the largest size sheet corresponding to the Width capacity of the hopper. The shorter andlesser width sheets S2 and S3 are shown disposed in different positions within the sheet stack and the shaded area CA represents the least common area ofv the three sheets. Thus it Will be seen that the sheet feeding belt 17 operating within this area at the roller 32 will at all times engage the leading or end sheet of the stack regardless of its disposition within the stack.

Another important feature of the above sheet feeding apparatus is the frictional characteristics of the sheet feeding and retarding members. With respect to the par.- ticular material of which the sheets in the stack are made, the sheet feeding belt 17, drive down roller 22 and retarding belt 44 have a higher coefficient of friction than that between two sheets. Also, with respect to the sheet vmate-` rial, the drive down roller 22 has a higher coefficient of friction than the retarding belt 44 or the sheet feeding belt 17 while the latter two preferably have substantially the same coeicient of friction. The friction of the retarding belt 44 and the sheet feeding belt 17=may be varied relative to one another, that is, either one may be higher than the other, provided there is a sufficient difference between the forces operating to advance the sheet stack and those operating on the retarding belt to effect a retarding action. In the illustrated embodiment, this is accomplished preferably by having higher forces operating on the retarding

belt rollers

52, 53 and 54 than the forces advancing the sheet stack, and also by reason of the fact that as a sheet is fed away from the stack by the sheet feeding belt 17 the forces operating on the sheet at the stack are becoming less and less while the forces operating on the sheet at the retarding belt are increasing up to the maximum at which point the sheet would be in the full grip of the retarding belt.

in operation, sheet feeding belt 17 is rotating and engages the top or end sheet of the stack to advance it downwardly into the nip of the rotating drive down roller 22 and retarding belt 44, the latter being rotated at a lesser linear velocity than the surface velocity of the drive down roller 22. 1t will be noted that the sheet feeding belt 17 is slightly below the periphery of the drive down roller Z2 (FlG. 3) so that the drive down roller continues advancing the sheet and, having a higher coeliicient of friction than the retarding belt 44, feeds the sheet forwardly against the resistance of the retarding belt.

When the sheet has passed the area of roller 32, sheet feeding belt 17 will commence feeding the next succeeding sheet in the stack, however, when this second sheet reaches the retarding belt 44 it will be held back because of the diiference in forces and the relative frictional characteristics of the two belts as explained above. The sheet feeding belt 17 will then be sliding on the second sheet until the first sheet is fed out of the nip of the drive down roller 22, at which point the drive down roller will then commence feeding the second sheet forwardly.

The separating action of retarding belt 44 may be more fully understood by taking an extreme case wherein three sheets adhere together and have been simultaneously separated from the stack S by the sheet feeding belt 17. As seen in FIG. l2, sheet 3 will be retarded by belt 44 while sheets 1 and 2 will be advanced by drive down roller 22 until sheet 2 is engaged by another portion of retarding belt 44. At this point, retarding belt 44 will hold back sheet 2 While drive down roller 22 feeds sheet 1 forwardly. After sheet 1 leaves the nip of drive down roller 22, the drive down roller will then feed out sheet 2 in the same manner, and then follow with sheet 3 so that multiplefed sheets will be separated and forwarded in their proper sequence.

As the leading edge of a sheet emerges from drive down roller 22 and retarding belt 44 it is guided by deliector 43 (FIG. 3) into a chute portion 91 formed by two sheet guide members 92 and 93. Guide member 92 is substantially hook-shaped and comprises an upwardly extending portion 94 (FIG. 5) bifurcated at 95 to provide clearance for retarding belt 44 which extends through the bifurcation, a lower arcuate portion 96, and a straight portion 97 at the delivery end of the guide member.

A forwarding roller 98 (FIGS. 3, 4 and 5) provided with a series of circular grooves or recesses 99 is securely mounted for rotation on a drive shaft 139 rotatably mounted in anti-friction bearings in a cylinder 101 having a liange 102 secured to base plate 13. Disposed in recesses 99 are fingers 103 of a stripper member 104 secured at one end to base plate 13, the ngers 163 serving to strip the sheets from the forwarding roller 98 in case they adh re to the roller by reason of static electricity, or other cause.

A link 165 (FGS. 3 and 5) is pivotally mounted at one end on a pin 136 fixed to base plate 13 and pivotally connected at its other end on a pin 197 secured to spaced brackets 1118 attached to guide member 92. A second link 1119 is pivotally mounted at one end on a pin 119 secured to base plate 13 and pivotally connected at its other end d on a pin 111 secured to spaced brackets 112 attached to guide member 92.

Guide member 92 is provided with a cut-out portion 113 for admitting a series of pressure rollers 114 to the forwarding roller 98. The pressure rollers 114 are respectively rotatably mounted on pins 115 secured to arms 116 of bell crank levers 117 pivotally mounted on pin 167, the levers 117 having arms 118 to which are secured one end of tension springs 119, the other end of the springs being secured to a pin 12u attached. at its ends to brackets 1GB.

Guide member 92 is also cut-out at 121 to admit a second series of pressure rollers 122 for engaging the forwarding roller 98. Rollers 122 are rotatably mounted respectively on pins 123 secured to arms 124 of bell crank levers 125 pivotally mounted on a pin 126 secured at its ends to spaced apart portions 127 of guide member 92, the levers having a second arm 128 to which is secured one end of tension springs 129, the other ends of which are attached to pin 111.

The guide member 92 and

pressure rollers

114 and 122 are normally locked in operative position as seen in FIG. 3, but are conveniently retracted to an open position, as seen in FIG. 5, for relieving a sheet jam in case one or more sheets become lodged in this region. For such purpose, there is provided a locking device comprising a channel-shaped latching plate 130 (FIGS. 6 and 7) secured to hase plate 13 and formed with an operating slot 131 communicating with an assembly or entry slot 13111. The ends of slot 131 terminate in

circular portions

132 and 133 adapted for slidably receiving a detent member 134 secured on the lower end portion of a plunger 135 siidably received in the spaced apart portions 127 of guide member 92 and extending through a finger grip 136 counterbored at 137. The headed portion 138 of plunger 135 is adapted for sliding movemeut in counterbore 137, while the shank 139 of the plunger is adapted for sliding movement along slot 131. A helical spring 140 under compression between the bottom face of counterbore 137 and the headed portion 138 of plunger 135 biases the plunger upwardly. As shown, the upward movement of plunger 135 is limited by a stop collar 141 secured to its lower end and which engages the underside of latching plate 130 at the limit of its movement.

To retract guide member 92 and its associated pressure roller assemblies from operating to open position, plunger 135 is depressed manually until detent 134 is below latching plate 130 and the lower portion of the plunger shank 139 is aligned with slot 131. Finger grip 136 is then pulled to draw shank 139 of the plunger along slot 131 until detent 134 is aligned with circular portion 133 at which place plunger 135 is then released to allow the detent 134 to engage and lock is circular portion 133. This movement of the locking device serve-s to rock

links

105 and 109 in a countercloekwise direction about

pins

106 and 110 respectively until guide member 92 and the pressure roller assemblies mounted thereon assume an open position away from the forwarding roller 95 as seen in FIG. 5,

ln the operation of sheet feeding, as sheets leave the drive'down roller 22 they will be closely spaced or in abutting relation, or possibly slightly overlapped. In order to eifect a definite spacing between the sheets, for-l warding roller 98 is rotated at a higher surface velocity than drive down roller 22. Also, the nip of the forwarding roller 98 and pressure rollers 122 is spaced from the nip of the drive down roller 22 and retarding belt 44 a distance somewhat less than the length of the shortest sheet. Accordingly, when the leading end of a sheet enters the nip of the forwarding roller 98 it will still be engaged by the drive down roller 22 and retarding belt 44, however, when the trailing end of the sheet leaves the drive down roller, the sheet will be advanced at a higher linear velocity by the forwarding roller than the next succeeding sheet being advanced by the drive down roller, thus effecting a definite spacing between successive sheets. The driving7 surface of the forwarding roller is frictional but of sufficient smoothness so that no injurious rubbing on the sheet will result while the sheet is still in the nip ofthe drive down roller.

The guide member 93 (FIGS. 3 and 5) comprises a bifurcated sheet guide element 142 secured -to an arm 143 attached to a cylindrical hub 144 (FIG. 4) mounted for rocking motion on cylinder 101 and retained axially on cylinder 101 by means of retaining rings 145 which snap into suitable grooves of pins 146 secured to and extending from cylinder 101. One end of a tension spring 147 is attached to a post 148 secured to hub 144 and the other end attached to a post 149 (FIG. 3) secured to base plate 13. The tension spring 147 retains guide member 93 in its operating position where arm 143 abuts a stop pin 158 fixed to base plate 13. Accordingly, when the operator is relieving the machine of a jam as explained above, he can at the same time provide further accessibility to the apparatus by rocking guide member 93 manually against the biasing action of tension spring 147 to open position as seen in FIG. 5.

The above described sheet feeding apparatus is well adapted for either ow feeding or intermittent feeding. In the latter case, a sensing device is disposed along the path of sheet feeding and operates to initiate actuation of clutch and brake devices, shortly to be described, to shut oit rotation of the sheet feeding belt 17 when the presence of a sheet is detected. One such sensing device 151, FIG. 4, may take a form similar to that described and claimed in a copending application of James A. Ogle, Serial No. 792,293, filed February 10, 1959, entitled Position Indicating Apparatus.

The sensing device 151 is secured to sheet guide element 142 and bridges across `a slot 152 in the guide el'ement 142. A source of radiation, such as a lamp bulb 153, and a radiation sensitive element 154 are carried bythe sensing device 151 and are positioned to function through slot 152 of guide element 142. Accordingly, rays of light from bulb 153 are reected from the surface of upwardly extending portion 94 of guide member 92 to impinge upon the radiationL sensitive element 154. When a sheet is fed into chute 91 and interrupts the light beam, the radiation sensitive element 154 will initiate actuation of the above-mentioned clutch and brake devices by means of suitable circuitry and electrical components, not shown, to shut off rotation of the sheet feeding belt 17. Upon receiving a signal to feed from associated apparatus not forming a part of the present invention, the clutch and brake devices Will again be actuated to resume rotation of the sheet feeding belt 17 for feeding the next succeeding sheet The drive for the sheetr feeding belt 17, drive down roller 22 and retarding belt 44 includes magnetic clutch and brake devices C and B respectively contained in a housing 155 as seen in FIG. 9, which are selectively operable to rotate or stop rotation of shaft 25. Shaft 25 is journalled in anti-friction bearings secured in housing 155 and is in spaced coaxial relation with a drive shaft 156 similarly journalled in housing 155 and rotated from motor 46 (FIG. 1) by means of a belt 157 and Ia flywheel pulley 158. n the clutch side of the drive, drive shaft 156 extends through a solenoid 159 which is secured to a wall 160 of housing 155 and adapted `to be energized for magnetizing a circular driving member 161 secured on the innerl end of drive shaft 156. Secured on the inner end of shaft is a circular armature 162 adjacent the driving member 161. On the brake side of the drive, shaft 25 extends through a solenoid 163vwhich is secured to a wall 164 of housing 155 and adapted to be energized for magnetically attracting a circular `armature 165 secured on shaft 25. Accordingly, when it is desired to rotate shaft 25, solenoid 159 is energized to magnetize drivi-ngmemben 161i. Driving member. 161. will there,-y

fore magnetically rotate armature 162 and shaft25. To stop rotation of shaft 25, solenoid 159 is de-energized to

de-clutch shafts

25 and 156 and solenoid 163 is simultaneously energized to magnetically attract and stopV armature and thus effectively brake rotation of shaft 25.

It can now be seen that the magnetic clutch and brake arrangement provides for instantaneous start-stop operations and enables the sheet feeding apparatus to be controlled with extreme precision in timing, a feature which is most valuable in intermittent feeding and for stopping the feeding apparatus in the event of a sheet jam.

For advancing the stack of sheets S to the sheet feeding belt 17 there is provided a stack pusher comprising an upper pusher 166 (FIGS. l and 3) and a lower pusher 167. Upper pusher 166 is formed as a rectangular plate and is supported in spaced relation to table 11 by means of a supporting member 168 extending through elongated slots 169 in table 11 and base plate 13 to the underside of the base plate where it is secured to a pusher carriage 17) (FIGS. 14 and 15). The lower pusher 167 is a rectangular block bevelled at its forward side at 171 (FIG. 3) and supported in spaced relation with table 11 and side plate 12 by means of rods 172 secured to a supporting member 173 which extends through elongated slots 174 in table 11 and base plate 13 to the underside of the base plate where it is secured to a pusher carriage 175. At the stack advance side of

pushers

166 and 167 is a rectangular exible stack compressing plate 176 having laterally extending lugs` 177 at its lower corner regions pivotally mounted on pins 173 secured to the lower pusher 167.

The pusher carriages and 175 (FIGS. 14 and 15) are similarly provided with

bearings

179 and 188 and 181 and 182 respectively secured therein and which are pro vided with a bore for slidably mounting the cariages on a way or guide shaft 183 secured at its ends to frame 14. The carriages are similarly maintained against rocking motion on guide shaft 183 by means of pairs of

rollers

184 and 185 rotatably mounted on depending

portions

186 and 187 respectively of carriages 17() and 175. The rollers of each pair embrace a second way or guide shaft 188 at diametrically opposite places, the shaft 188 being secured at its ends to frame 14.

Carriages

170 and 175 and their

respective pushers

166 and 167 are driven or urged in the direction of stack advance by yieldable constant force mechanism, one construction of which may take the form of clock-type constant force spring devices 189 and 190 (FIG. 15) secured to frame 14 and having

leads

191 and 192 secured to

pins

193 and 194 respectively attached to the carriages.

As seen in FIG. 15, theforward movement of the upper pusher carriage 170 in the direction of stack advance is limited by the position, or freely coupled relation, of the lower pusher carriage 175. In other words, when carriage is stationary, carriage 170 will also be held stationary by reason of bearing of carriage 170 abutting bearing 181 of carriage 175. On the other hand, when carriage 170 is held stationary, carriage 175 can move forwardly a limited distance until bearing 181 abuts bearing 179.

Accordingly, when the

pushers

166 and 167 are permited to move in the direction of stack advance by the biasing action of

spring devices

189 and 190 in a manner to be explained more fully hereinafter, pusher 166 will stop when it abuts the solid region of the unaligned sheet stack S (FIG. 3) while pusher 167 will move in advance of' pusher 166 to accommodate flexible stack compressing plate 176 to the shape of the sheet stack, thus to compress the stack at its lower loose region wherebythe sheets will be presented firmly along their length to the effective feeding portion of the sheet feeding belt 17. There is thus eliminated the possibility of the sheets buckling as they are separated from the stack by the feeding belt 17.

AsA mentioned above,l the carriages and pushers are driven or urged in the direction of stack advance by the spring devices 1&9 and 190, however, such movement is cotnrolled by means including an endless chain 195 (FIGS. 14 and 15) engaged about

idler sprocket wheels

196 and 197 rotatably mounted on fixed shafts, and a sprocket Wheel 198 associated with a one-way clutch device shown in FIG. 8. An upwardly extending pin 199 secured to an arm 26d attached to support 173 extends through the upper arm 291 of chain 195 in mesh therewith.

The clutch device illustrated in FG. 8 is used for con trolling the movement of chain 195' and comprises a stub shaft 2i)2 secured on a drive shaft 203 of a motor 294 (FIGS. l and 3). Sprocket wheel 198 is rotatably mounted on the shank 202e of stub shaft 202 and axially secured thereon by means of a collar 29S pinned to the stub shaft. A left-hand helical spring clutch 206 is normally tightly wound around a shoulder 207 of stub shaft 292 and the hub 208 of sprocket wheel 198.

Accordingly, when drive shaft 203 is not rotating, sprocket wheel 198 will be locked to stub shaft 202 by spring clutch 236 whereby chain 195 and

pushers

166 and 167 will be held stationary against the biasing action of

spring devices

189 and 190. To enable the pushers to move forwardly under the action of the spring devices for sheet feeding operation, drive shaft 263 is rotated counterclockwise as viewed in FIG. 14 whereby spring clutch 2126 is unwrapped and sprocket wheel 198 allowed to rotate with the chain 195 so that the

pushers

166 and 167 will be advanced toward the sheet stack S by the spring devices 139 and 19t). When the pushers abut the sheet stack, continued rotation of drive shaft 203 serves to keep spring clutch 266 unwound so that sprocket wheel 198 is allowed to rotate with chain 195 and the sheet stack advanced as sheets are individually separated from the stack by sheet feeding belt 17.

After a sheet feeding run has been completed,

pushers

166 and 167 may be retracted to a convenient loading position by reversing motor 204. Rotation of drive shaft 203 in the opposite direction serves to tighten spring clutch 2% and thus provides a positive drive for retracting the pushers. When the pushers have been returned to loading position, motor 264 then may be shut off whereby spring clutch 206 will remain engaged and the pushers retained in retracted position.

From the foregoing description of a specific apparatus illustrating the fundamental features of the invention, it will now be apparent to those skilled in the art that the invention may be constructed in a variety of forms without departing from the true spirit and scope thereof. Accordingly, it is to be understood that the illustrated apparatus disclosed herein is a preferred embodiment of the invention and that the invention is not to be limited thereby but only by the subjoined claims.

What is claimed is:

l. Sheet feeding mechanism comprising in combination, a sheet stack hopper, means for separating sheets individually and successively from a stack in said hopper, means for advancing said stack along said hopper to said separating means, a first sheet feeding roller for advancing the separated sheets, means movable between open and closed positions and in arcuate contact with said roller in the closed position for retarding sheets in excess of the foremost one separated from said stack, means for retracting said retarding means from closed to open position away from said roller, a second sheet feeding roller, sheet guide means movable between open and closed positions and operative in the closed position to direct the advanced sheets to the second sheet feeding roller, pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets when said sheet guide means is in the closed position, and means operable for withdrawing said sheet guide means from closed to open position and said pressure means away from said second sheet feeding roller.

2. In a machine for feeding sheets from an intermixed stack of various size sheets, the combination comprising, a sheet stack hopper, an endless sheet feeding belt adapted for engaging said sheets in the least common area thereof for separating said sheets individually and successively from a stack in said hopper, means for advancing said stack along said hopper to said sheet feeding belt, a first sheet feeding roller for advancing the separated sheets, means movable between open and closed positions and in arcuate Contact with said roller in the closed position for retarding sheets in excess of the foremost one separated from said stack, means operable for retracting said retarding means from closedl to open position away from said roller, a second sheet feeding roller, sheet guide means movable between open and closed positions and operative in the closed position to direct the advanced sheets to the second sheet feeding roller, pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets when said sheet guide means is in the closed position, and means operable for withdrawing said sheet guide means from closed to open position and said pressure means away from said second sheet feeding roller.

3. 1n a machine for feeding sheet material, apparatus comprising, a hopper for supporting a stack of said material, means for separating sheets of material individually and successively from said stack, means for advancing said stack along said hopper to said separating means, a first sheet feeding roller for advancing :the separated sheets, means movable between open and closed positions and in arcuate contact with said roller in the closed position for retarding sheets in excess of the foremost one separated from said stack, said retarding means having a lower coefficient of friction with respect to said material than said roller, means operable for retracting said retarding means from closed to open position away from said roller, a second sheet feeding roller, sheet guide means movable between open and closed positions and operative in the closed position to direct the advanced sheets to the second sheet feeding roller, pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets when said sheet guide means is in the closed position, and means operable for withdrawing said sheet guide means from closed to open position and said pressure means away from said second sheet feeding roller.

4. Sheet feeding apparatus comprising, a sheet stack hopper, an endless sheet feeding belt for separating sheets individually and successively from a stack in said hopper, first and second stack pushers adapted for engaging respective areas of said stack for advancing the stack along said hopper to said sheet feeding belt, drive means 'for said pushers whereby one of said pushers may move in advance of the other pusher to accommodate itself to variations in thickness of said stack, a first sheet feeding ro er for advancing the separated sheets, means in arcuate contact with said roller for retarding sheets in excess of the foremost one separated from said stack, a second sheet feeding roller, sheet guide means to direct the advanced sheets to the second sheet feeding roller, and pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets.

5. Sheet feeding apparatus comprising, a sheet stack hopper, an endless sheet feeding belt for separating sheets individually and successively from a stack in said hopper, first and second stack pushers adapted for engaging respective areas of said stack for advancing the stack along said hopper to said sheet feeding belt, drive means for said pushers whereby one of said pushers may move in advance of the other pusher to acconunodate itself to aparaat variations in thickness of said stack, a iirst sheet feeding roller for advancing the separated sheets, means movable between open and closed positions and in arcuate contact with said roller in the closed position for retarding sheets in excess of the foremost one separated from said stack, means operable for retracting said retarding means from closed to open position away from said roller, a second sheet feeding roller, sheet guide means movable between open and closed positions and operative in the closed position to direct the advanced sheets to the second sheet feeding roller, pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets when said sheet guide means is in the closed position, and means operable for withdrawing said sheet guide means from closed to open position and said pressure means away from said second sheet feeding roller.

6. In a machine for feeding sheet material from an intermixed stack of various size sheets, the combination comprising, a sheet stack hopper, an endless sheet feeding belt adapted for engaging said sheets in the least common area thereof for separating said sheets individually and successively from a `stack in said hopper, first and second stack pushers adapted for engaging respective areas of said stack for advancing said stack along said hopper to said sheet feeding belt, drive means for said pushers whereby one of said pushers may move in advance of the other pusher to accommodate itself to variations in thickness of said stack, a first sheet feeding roller for advancing the separated sheets, an endless sheet retarding belt movable between open and closed positions and in arcuate contact with a portion of the driving surface of said roller in the closed position for retarding Asheets in excess of the foremost one separated from said stack, manually operable means for retracting said retarding belt from closed to open position away from said roller, a second sheet feeding roller in advance of said first roller and being operable at a higher surfacevelocity than said first roller, sheet guide means movable between open and closed positions and operative in the closed position to direct the advanced sheets to the second sheet feeding roller, pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets when said sheet guide means is in the closed position, said second roller and pressure means being spaced from said first roller and retarding belt a distance somewhat less than the length of said sheets, and manually operable means for withdrawing said sheet guide means from closed to open position and said pressure means away from said second sheet feeding roller.

7. In a sheet feeding machine, the combination comprising, an endless sheet feeding belt, a stack hopper, tirst and second stack pushers adapted for engaging respective areas of a sheet stack for advancing said stack along the hopper to the sheet feeding belt, said stack pushers being freely coupled to allow limited relative movement between them in the direction of the stack advance, a iiexible member carried by one of the pushers, and drive means for said pushers whereby one of said pushers may move in advance of the other pusher within said limited relative movement to condition said flexible member to the shape of a sheet stack having variations in thickness.

8. In a sheet feeding machine, the combination comprising, a stack hopper, first and second stack pushers adapted for engaging respective areas of a sheet stack for advancing said stack along said hopper, a xed shaft slidably mounting both said stack pushers, means on the iirst stack pusher to limit the movement of the second stack pusher in the direction of stack advance, and means urging said pushers along said hopper.

9. In a machine for feeding sheets from an intermixed stack of various size sheets, the combination comprising, a stack hopper, an endless sheet feeding belt adapted for engaging said sheets in the least common area thereof, first and second stack pusher-s adapted for engaging-respective areas of said stack for advancing said stack along said hopper to the sheet feeding belt, means mounting said pushers for confined parallel movement, means on the first stack pusher to limit movement of the second stack pusher in the direction of stack advance, and means urging said pushers along said hopper.

i0. In a sheet feeding machine, the combination cornprising, a stack hopper, first and second stack pushers adapted for engaging respective areas of a sheet stack for advancing said stack along said hopper, means on the first stack pusher to limit movement of the second stack pusher in the direction of stack advance, means urging said pushers along said hopper, and selectively operable power means for allowing said urging means to advance said pusliers or for retracting said pushers in opposition to the urging means.

ll. Sheet stack advancing mechanism, comprising, a stack hopper, iirst and second stack pushers for advancing a stack of sheets along said hopper, a flexible member at the stack advancing side of said pushers and being mounted on one of said pushers, means on the first pusher to limit movement of the second pusher in the direction of stack advance, means urging said pushers along said hopper whereby said first pusher may move in advance of the second pusher to condition said liexible member to the shape of a sheet stack having variations in thickness, a chain coupled to said first pusher, and selectively operable power means coupled to said chain to allow movement of said chain in one direction in response to movement of said pushers by said urging means or to drive said chain in the opposite direction in opposition to said urging means.

12. in combination with an endless sheet feeding belt, the apparatus comprising, a sheet stack support, first and second stack pushers for advancing a stack of sheets along said support, a stack compressing member at the stack advancing side of said pushers and being mounted on one of said pushers, means on the first pusher to limit movement of th-e second pusher in the direction of stack advance, means urging said pushers along said support whereby said iirst pusher may move in advance of the second pusher to condition said compressing member to the shape of a sheet stack having variations in thickness, rotary power means, a chain coupled to the first pusher, and one-way clutch means for engaging the chain with said power means, said clutch means allowing the chain and pushers to move in response to the urging means when the power means is rotated in one direction and engaging the chain with the power means for driving the chain and pushers in opposition to the urging means when the power means is rotated in the opposite direction.

13. Sheet feeding mechanism comprising in combination, a sheet stack hopper, an endless sheet feeding belt for frictionally separating sheets individually and successively from a stack in said hopper, yieldable drive means for advancing said stack in a horizontal direction along said hopper to said sheet feeding belt, a first sheet feeding roller for advancing the separated sheets, means movable between open and closed positions and in arcuate contact with said roller in the closed position for retarding sheets in excess of the foremost one separated from said stack, means for retracting said retarding means from closed to open position away from said roller, a second sheet feeding roller, sheet guide means movable between open and closed positions and operative in the closed position to direct the advanced sheets to the second sheet feeding roller, pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets when said sheet guide means is in the closed position, and means operable for withdrawing said sheet guide means from closed to open position and said pressure means away from said second sheet feeding roller.

14. In a machine for feeding sheets from an intermixed stack of various size sheets, the combination, a sheet stack hopper, an endless sheet feeding belt adapted for engaging said sheets in the least common area thereof for separating said sheets individually and successively from a stack in said hopper, means for advancing said stack along said hopper to said sheet feeding belt, a first sneet feeding roller for advancing the separated sheets, an endless sheet retarding belt movable between open and closed positions and in arcuate contact with said roller in the closed position for retarding sheets in excess of the foremost one separated from said stack, yieldable means for pressing said retarding belt into said arcuate contact with said roller, means operable for retracting said retarding belt from closed to open position away from said roller, a second sheet feeding roller, sheet guide means movable between open and closed positions and operative in the closed position to `direct the advanced sheets to the second sheet feeding roller, pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets when said sheet guide means is in the closed position, and means operable for withdrawing said sheet guide means from closed to open position and said pressure means away from said second sheet feeding roller.

15. In a machine for feeding sheet material, apparatus comprising, a hopper for supporting a stack of said material, an endless sheet feeding belt for frictionally separating sheets of material individually and successively from said stack, yieldable drive means for advancing said stack in a horizontal direction along said hopper to said sheet feeding belt, a first sheet feeding roller for advancing the separated sheets, an endless sheet retarding belt movable between open and closed positions and in arcuate contact with said roller in the closed position for retarding sheets in excess of the foremost one separated from said stack, said retarding belt having a lower coeiicient of friction with respect to said material than said roller, yieldable means pressing said retarding belt into said arcuate contact with said roller, means for rotating said retarding belt, means operable for retracting said retarding belt from closed to open position away from said roller, a second sheet feeding roller, sheet guide means movable between open and closed positions and operative in the closed position to direct the advanced sheets to the second sheet feeding roller, pressure means carried by said sheet guide means and cooperating with said second sheet feeding roller for forwarding the advanced sheets when said sheet guide means is in the closed position, and means operable for withdrawing said sheet guide means from closed to open position and said pressure means away from said second sheet feeding roller.

16. In a sheet feeding machine, the combination comprising, a stack hopper, a first stack pusher etective for advancing a stack of sheets along said hopper, a second stack pusher arranged for engaging a marginal area of said stack along an edge thereof, means coupling said pushers and allowing relative limited movement between them in the direction of stack advance, and drive means for said stack pushers whereby said second stack pusher may move in advance of said first stack pusher within said limited movement to accommodate itself to a variation in thickness of said stack at said marginal area region thereof.

17. In a sheet feeding machine, the combination cornprising, a stack hopper, first and second stack pushers adapted for engaging respective areas of a stack of sheets in said hopper for advancing said stack :along the hopper in a forward direction, said stack pushers being mounted for independent movement, means on the first stack pusher to limit movement of the second stack pusher in the direction of stack advance, means urging said stack pushers along said hopper, and means for simultaneously returning said stack pushers in the reverse direction.

18. In a machine for feeding sheets from an intermixed stack of various size sheets in which the sheets differ in length and width, the combination comprising, a hopper for containing a stack of such sheets, an endless sheet feeding belt for feeding sheets from said stack and having a width and arrangement for engaging successive sheets of the stack only in a region defining the least common area of the intermixed sheets, irst and second stack pushers adapted for engaging respective areas of said stack for advancing the stack along said hopper to said sheet feeding belt, said stack pushers being mounted for confined movement along parallel lines, means on one of said pushers to limit movement of the other pusher in the direction of stack advance, and means urging said stack pushers along said hopper for advancing said stack.

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