US3525517A - Sheet feeding apparatus - Google Patents

Description

Aug. 25, 1970 D. E. TOBY SHEET FEEDING APPARATUS Filed Nov. 15, 1967 2 Sheets-Sheet 1 Aug. 25, 1910 Filed Nov. 1-3, 1967 D. E. TOBY SHEET FEEDING APPARATUS Ill 2 Sheets-S'neet 2 United States Patent SHEET FEEDING APPARATUS Dennis E. Toby, Lake Zurich, 111., assignor to Addressagraph-Multigraph Corporation, Mount Prospect, 11].,

a corporation of Delaware Filed Nov. 13, 1967, Ser. No. 682,252 Int. Cl. B65h 3/06 US. Cl. 271-36 11 Claims ABSTRACT OF THE DISCLOSURE A horizontal tray supports a stack of sheets to be fed one at a time from the stack by a spaced pair of rotatable friction rollers. The rollers are supported on a shaft mounted for free pivotal movement in a vertical direction so that the rollers engage the top sheet with equal forces and skewed feeding is prevented. A member engages the shaft between the rollers and serves to both pivotally support the shaft, and also to rotate the shaft in order to advance a sheet.

The present invention relates to apparatus for feeding individual sheets from the top of a stack of sheets, and has for a primary object the provision of novel apparatus for feeding sheets without skewing.

Many types of sheet feeding assemblies have been devised for feeding individual sheets from a stack into automatic copy making machines or the like. Known sheet feeding assemblies may include a tray or table or other support upon which is placed a stack of sheets to be fed one by one. Friction rollers, wheels or other feed members rest upon the top of the stack, and are rotated to advance the upper-most sheet from the stack into a copy making machine or other sheet utilizing apparatus. The friction rollers or other members may be mounted on a shaft which is maintained in a fixed horizontal orientation and which is movable in a vertical direction so that the friction rollers continue to engage the uppermost sheet as the stack is diminished. Usually means are provided for rotating the shaft when it is desired to advance a sheet from the stack.

One problem encountered with known sheet feeding assemblies is the skewed feeding of sheets from the stack. Skewed feeding results when one side of the sheet is fed faster than the other side so that the leading edge of the sheet is advanced at an angle away from the stack. When the sheet is fed into copy making apparatus, for example, a skewed sheet can become fouled in the machine and cause jamming or the like. Even if the sheet does not become jammed, a copy produced on the sheet will be skewed in relation to the sheet.

It is believed that the skewed feeding of sheets results when a pair of sheet feeding friction rollers engages the uppermost sheet of the stack with unequal forces. The differential in force can cause a rotational or torque effect on the sheet causing it to become skewed as it is fed. When both the stack supporting tray and the friction roller supporting shaft are located horizontally and thus are parallel to one another, a differential in feeding force "ice intended, it would be desirable to provide an improved arrangement for feeding sheets without skewing wherein the stack supporting tray may be fixed.

Accordingly, it is an object of the present invention to provide new and improved sheet feeding apparatus.

Another object is to provide sheet feeding apparatus for preventing skewed feeding of sheets.

A further object is to provide new and improved sheet feeding apparatus wherein the forces applied by spaced sheet feeding members are equal and wherein the sheet supporting tray is fixed rather than pivotally mounted.

In accordance with these and many other objects, a sheet feeding apparatus constructed in accordance with the invention may include a tray mounted in a fixed, horizontal position for supporting a stack of sheets to be fed from the stack to a copying machine or the like. A shaft carrying a spaced pair of sheet driving friction rollers is mounted above the stack in a direction transverse to the direction in which sheets are fed, and the shaft is vertically movable so that the friction rollers always rest upon the upper sheet of the stack. In accordance with an important feature of the invention, the roller shaft is mounted for pivotal movement in a vertical plane so that the forces exerted by the rollers against the top sheet of a the stack are equalized and skewed feeding of the sheets can result, for example, when one of the feed rollers wears f that patent is highly satisfactory for the uses for which it is is prevented.

In accordance with the invention the shaft is engaged midway between the friction rollers by a combined driving element and pivotal support with which the shaft and rollers are rotated in order to advance a sheet. The roller supporting shaft is hollow, and a concentric drive shaft is positioned within the roller shaft. The combined driving element and pivot support couples the drive shaft to the center of the roller shaft for not only driving the roller shaft but also for allowing the roller shaft freely to pivot.

Many other objects and advantages of the present invention will become apparent from considering the following detailed description in conjunction with the drawings in which:

FIG. 1 is a top plan view of a sheet feeding apparatus constructed in accordance with the present invention;

FIG. 2 is a sectional view taken along the line 22 of FIG. 1 and illustrating the apparatus together with a supply of sheets to be fed; and

FIG. 3 is a fragmentary, partly diagrammatic sectional view taken along the line 33 of FIG. 2 illustrating the manner in which the sheet feeding members apply equal driving forces for advancing a sheet from an uneven stack of sheets.

Having reference now to the drawings, there is illus trated a sheet feeding apparatus or assembly designated as a whole by the reference numeral 10. In general, the assembly 10 includes a tray or table 12 adapted to support a stack of sheets 14. The sheets 14 are advanced one by one from the top of the stack by a pair of sheet driving members in the form of spaced friction wheels or rollers 16 and 18 formed of rubber or other material capable of frictionally engaging the sheets 14. In accordance with an important feature of the present invention, the friction wheels 16 and 18 are carried on a freely pivoted roller shaft 20 to the end that the friction rollers 16 and 18 act together and with equal force to advance the top sheet from the stack without skewing.

More specifically, the tray 12 comprises a uniplanar element adapted to be supported on a pair of support bars 22 and 24 (FIG. 2) in a fixed horizontal position at the entrance to an automatic copying machine or other sheet utilizing equipment. As sheets are advanced from the stack toward the right as illustrated in FIG. 2, they are directed by a sheet guide 26 between a pair of sheet propelling rollers 28 and 30 journalled for rotation in a pair of plates or walls 32 and 34 and serving to advance the sheets away from the apparatus 10.

In order to guide the sheets 14 as they are advanced and to position the stack of sheets on the tray 12, the tray is provided with a pair of side rails or guides 36 and 38 preferably adjustable to accommodate a wide variety of sheet widths. In order to assure that individual sheets are separated from the stack when advanced, a pair of separator arms 40 and 42 are pivotally supported on the side rails 36 and 38. Each of the arms 40 and 42 includes a forwardly extending portion 44 disposed alongside the stack of sheets, together with an inwardly portion 46 overlying the corners of the leading edge of the uppermost sheet. In addition, each separator arm includes a downwardly extending portion 48 providing an abutment for the front of the stack. As will be understood by those skilled in the art, the tray 12 is provided with a downwardly depending flange 50 (FIG. 2) supporting a switch 52 providing an indication when the supply of sheets 14 is depleted.

In the feeding of individual sheets from the top of a stack of sheets it has been found to be important that the friction rollers advancing the sheets engage the uppermost sheet with equal forces. If the rollers engage the uppermost sheet with unequal forces, one side of the sheet tends to be advanced faster than the other side and as a result the sheet becomes skewed in the feeding operation. In order to overcome this problem, arrangements have been devised in which the sheet supporting tray is pivotally mounted so that the stack of sheets can pivot to a position in which the forces applied by the spaced rollers are equal, even if the rollers are unevenly worn or if the stack of sheets is uneven.

In accordance with an important feature of the present invention, the forces applied by the friction rollers 16 and 18 are equal even though the tray 12 is mounted in a fixed horizontal position. Accordingly, the roller shaft 20 upon which the friction rollers 16 and 18 are mounted is free to pivot in a vertical direction so that the rollers can move to that position in which the forces applied by the rollers are equal. In accordance with a feature of the invention, this pivoting movement is provided for by means of a novel member 54 comprising a combined pivot support and drive element which not only pivotally mounts the shaft 20 but also imparts rotation to the shaft 20 when it is desired to advance a sheet from the stack.

More specifically, the member 54 comprises a somewhat ball-shaped body snugly received within the hollow central portion of the shaft 20 midway between the rollers 16 and 18. The rounded shape of the member 54 permits the shaft 20 to pivot about the member 54 so that, as best illustrated in FIG. 3, where the apparatus is shown with an uneven stack of sheets 14, the shaft can freely pivot to that position in which both the friction rollers 16 and 18 evenly engage the uppermost sheet of the stack. In order to impart rotation to the shaft 20 and the rollers 16 and 18 for advancing a sheet from the stack, the member 54 is drivingly related to the shaft 20. Thus the member 54 includes a pair of drive pins 56 received in slots 58 (FIG. 3) in the wall of the shaft 20. The pins 56 fit loosely enough in the'slots 58 so that free pivotal movement of the shaft 20 is not impeded.

In order to rotate the member 54, the member 54 is mounted upon a drive shaft 60 concentrically received within the hollow shaft 20. The drive shaft 60 is journalled for rotation in a pair of pivot links or arms 62 and 64 which arms are also pivotally related to a main drive shaft 66 (FIGS. 1 and 2) rotatably mounted in the walls 32 and 34. The links or arms 62 and 64 permit the shaft 60 as well as the shaft 20 and rollers 16 and 18 freely to move in a vertical direction so that the rollers rest upon the top of the stack of sheets as the stack is depleted.

When it is desired to advance a single sheet from the top of the stack, the main drive shaft 66 is rotated by suitable means (not shown). Rotation is imparted to the drive shaft 60 by means of a drive belt 68 (FIG. 1) running on a pair of pulleys 70 and 72 attached respectively to the shafts 60 and 66. When the shaft 60 is rotated, the member 54 imparts rotation to the shaft 20 and thereby to the rollers 16 and 18. The rollers 16 and 18 thereupon apply a force to the top sheet of the stack for advancing the sheet away from the apparatus 10. Since the shaft 20 is freely pivotable about the member 54, the forces applied to the uppermost sheet by the rollers 16 and 18 are equal and the sheet is fed without skewing.

In order to replenish or change the stack of sheets, the apparatus 10 includes a lift bar 74 for raising the separator arms 40 and 42 as well as the shaft 20 and rollers 16 and 18 away from the stacks of sheets in the tray 12. The bar 74 extends through slots 76 in upwardly extending flanges 78 of the arms 40 and 42. Normally the bar 74 occupies the position illustrated in FIG. 2 wherein the separator arms rest upon the stack of sheets. When the bar is lifted, the separator arms 40 and 42 are pulled upwardly until they engage the shaft 20, at which time the shaft 20 is also moved upwardly away from the stack of sheets. The bar 74 is retained in the raised position while the stack of sheets is replenished or replaced by resting the bar on shoulders 80 provided on a spaced pair of upwardly extending flanges 82 at the sides of tray 12. When the bar is moved off of the shoulders 80, the separator arms 40 and 42 as well as the shaft 30 and rollers 16 and 18 return to their normal positions.

Although the present invention has been described with reference to a single embodiment, it should be understood that many other modifications and embodiments can be devised by those skilled in the art. Accordingly, the details of the described embodiment should not be taken to limit the present invention except insofar as included in the following calims.

What is claimed and desired to be secured by Letters Patent of the United States is:

1. Apparatus for feeding sheets from the top of a stack comprising a structure for supporting the stack of sheets in a horizontal position, a pair of sheet feed members engageable with the top of the stack at spaced regions along a line transverse to the direction of movement, a supporting structure for said pair of sheet feed members, and means mounting said supporting structure for pivotal movement about a point between said regions so that said sheet feed members are able to move to a position wherein said sheet feed members engage the top sheet of the stack with equal forces.

2. The apparatus of claim 1, said pair of sheet feed members and said supporting structure comprising a pair of friction rollers and a roller shaft supporting said rollers.

3. The apparatus of claim 2, said mounting means comiprising pivot means supporting said shaft between said rollers.

4. The apparatus of claim 3-, said mounting means including drive means drivingly coupled to said shaft for rotating said shaft thereby to advance a sheet from the stack.

5. Sheet feeding apparatus for advancing sheets from the top of a stack comprising a shaft overlying the stack, a pair of spaced feed rollers on said shaft adapted to rest on the top sheet of the stack, means engaging said shaft for mounting said shaft for free pivotal movement in a generally vertical plane permitting said shaft to tilt relative to horizontal, and means for rotating said shaft about its central longitudinal axis to advance the top sheet from the stack.

6. The sheet feeding apparatus of claim 5, said mounting means and said rotating means both comprising a single member pivotally and drivingly engaging said shaft.

7. The sheet feeding apparatus of claim 6, said member engaging said shaft midway between said pair of sheet feed rollers.

8. An assembly for advancing sheets one by one from a stack of sheets supported in a generally horizontal position, said apparatus comprising:

a first shaft overlying the stack of sheets; a second shaft concentric with said first shaft; a pair of friction rollers supported on said first shaft; means mounting both said shafts for free vertical movement so that said friction rollers are adapted to rest on the top sheet of the stack;

means for rotating said second shaft when it is desired to advance the top sheet from the stack; and

means pivotally and drivingly related between said first and second shafts for rotating said first shaft .in response to rotation of said second shaft and for allowing said first shaft to pivot with respect to said second shaft to a position wherein said friction rollers engage the top sheet with equal forces.

9. The assembly of claim 8;

said first shaft having a hollow center;

said second shaft being disposed within said first shaft;

and

said pivotally and drivingly related means comprising a member on said second shaft within said first shaft midway between said friction rollers.

10. The assembly of claim 9; said member comprising a body snuggly received within said first shaft and about which said first shaft freely pivots; and at least one drive transmitting element extending outwardly from said body drivingly to engage said first shaft.

11. Sheet feeding apparatus for advancing sheets from the top of a stack in a given direction, comprising:

means for supporting the stack in a generally horizontal position;

a shaft overlying the stack which is disposed along a line that is transverse to the direction of movement of said sheet;

a pair of feed rollers on said shaft adapted to rest on the top sheet of the stack; and

means for mounting said shaft so that it is free to pivot and move in a generally vertical plane, said mounting means including a member pivotally and drivingly engaging said shaft at a point midway between said pair of feed rollers.

References Cited UNITED STATES PATENTS 2,571,942 10/ 1951 Properzi 27136 EDWARD SROKA, Primary Examiner

Images