US3276770A

US3276770A - Sheet feeding apparatus

Info

Publication number: US3276770A
Application number: US394780A
Authority: US
Inventors: Augustus W Griswold
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1964-09-08
Filing date: 1964-09-08
Publication date: 1966-10-04
Anticipated expiration: 1983-10-04
Also published as: GB1055215A; DE1237587B

Description

oct. 4, 1966 5 Sheets-Sheet l Filed Sept. 8, 1964 FIG.

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AUGUSTUS w. GRISWOLD FG. 2 E), k

ATTORNEYS Oct. 4, 1966 A. w. GRlswoLD 3,276,770

SHEET FEEDING APPARATUS Filed Sept. 8, 1964 5 Sheets-Sheet 2 2 O22 rl r1 acR-z lcR-l F IG. 4

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if FWG ILS SR-| RSL'I 2L5 ICR-2 ZCR-I SOL-2 6 N VEN TOR.

4 AUGUSTUS wmswoLD w St A TTOR/VE YS Oct. 4, 1966 A. w. GRlswoLD SHEET FEEDING APPARATUS 5 Sheets-Sheet 5 Filed Sept. 8, 1964 F/G. I6

NVENTOR. AUGUSTUSVGQRISWOLD BY @QQ ATTORNEYS United States Patent O 3,276,770 SHEET FEEDING APPARATUS Augustus W. Griswold, Rochester, N.Y., assignor to Xerox Corporation, Rochester, N. a corporation of New York Filed Sept. 8, 1964, Ser. No. 394,780

6 Claims. (Cl. 271-10) This invention relates to a sheet feeding device and, particularly, to apparatus for seriatim sheet feeding from a stack of sheets.

Sheet feeding of paper or other types of sheets has always been impaired by the problem of adjacent sheets sticking to one another and interfering with the uniform feeding of single sheets. The sheets tend to stick together because of the surface condition of the sheets, foreign material on the surface of the sheets tending to adhere to adjacent sheets, and static electricity Which can build up on the surface of a sheet and attract adjacent sheets. Most prior art sheet feeding devices are of the type which frictionally force the top sheet to shear from the top of the stack by applying friction in the direction of sheet feeding. The sheet is forced to slide along the top of the stack either breaking the adhesion between the sheets or dragging subsequent sheets away from the stack. These types of devices have not been completely satisfactory because of the lack of reliability in consistently feeding a single sheet at a time. Applicants invention overcomes the problem of adhesion between the sheets and reduces the frictional contact between the sheets to a minimum. Rather than applying a frictional pushing or dragging force against the top sheet applicants invention utilizes a rotating frictional disc which applies a twisting force to the top sheet of the stack. Means provided at the corner of the sheet cause the sheet to buckle and separate from the stack thus reducing the adhesion between the adjacent sheets.

In one embodiment the top sheet is rotated through an arc to a pair of feed rollers. In another embodiment the top sheet is rotated through an arc a distance sucient to break the frictional contact between sheets and rotated back to its original position for subsequent feeding. During separation, there is no sliding -frictional movement of the sheet in the direction of sheet feeding, thus subsequent sheets are not urged in the direction of sheet feeding and do not tend to follow the sheet being fed. By the rotational movement and the buckling effect produced `on the top sheet and subsequent sheets which tend to rotate with the top sheet the sheets are fanned out and separated, one from the other. The fanning of the van'ous sheets breaks any adhesion or stickiness or static electricity between the various sheets permitting the sheets to be easily fed one at a time from the stack.

It is the primary object of this invention to improve sheet separating devices to facilitate seriatim feeding of sheets from a stack.

It is also an object of this invention to improve sheet feeding devices to break any adhesion or stickness between the various sheets of a stack prior to sheet feeding.

It is a further object of this invention to provide a simple and economically constructed device that separates sheets from a stack, one at a time, with a simple rotary motion of a friction member.

These and other objects of the invention are attained by means of a rotating disc placed on the center of a stack of sheets and rotated in contact with the top sheet to frictionally rotate the top sheet so that the corners of the sheet are caused to buckle by corner posts positioned in interference relationship with the rotation of the sheet, thus breaking the adhesion and frictional forces between the various sheets.

ice

For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following detailed description `of the invention to be read in connection with the accompanying drawings,

wherein:

FIG. l is a side view of one embodiment of sheet feed apparatus with portions broken away to show internal construction of the apparatus;

FIG. 2 is atop sectional View of the apparatus taken along lines 2 2 of FIG. 1;

FIGS. 3 and 4 are a top and side schematic view, respectively, of the friction disc and rollers of the apparatus in a position prior to feeding a sheet from a document stack;

FIGS. 5 and 6 are a top and side schematic view, respectively, of the friction disc and rollers of the apparatus in a position wherein the friction disc is rotating and buckling the top sheet of a documentstack;

FIGS. 7 and 8 are a top and side schematic view, respectively, of the friction disc and rollers of the apparatus in a position wherein the friction disc has rotated the top sheet of a document stack to be fed by the feed rollers;

FIGS. 9 and l0 are a top and side schematic view, respectively, of the friction disc and rollers of the apparatus in a position wherein the friction disc is being removed from the sheet stack and the top sheet is being fed by the feed rollers;

FIG..11 is a schematic electrical wiring diagram of the apparatus shown in FIG. 1;

FIG. 12 is an enlarged view of the corner posts and snubbers taken along line 12-12 of FIG. 2;

FIGS. 13 and 14 are a top and side schematic view, respectively, of a second embodiment of the apparatus with the friction disc in a rotated position;

FIGS. 15 and 16 are a top and side schematic view, respectively, of a second embodiment of the apparatus with the friction disc returned toits original position;

FIGS. 17 and 18 are a top and side schematic View, respectively, of a second embodiment of the apparatus with the friction disc pivoted forward to advance the top sheet for feeding;

FIG. 19 is an isometric representation of an alternative apparatus for advancing a separated sheet from the stack.

Referring to FIGURES 1 and 2 there is seen one embodiment of a sheet feeder constructed in accordance with the present invention. A stack of sheets, indicated generally as 2, is supported on a tray or platform 4 Within a pair of side frame members 6. The platform 4 is urged upward by an arrangement of compression springs 8, only one of which is shown. The sheet stack is restrained in its upward movement by snubbers 10 overlapping each corner of the stack. The snubbers 10 are mounted on corner posts or sheet buckling means 12 which retain the stack and produce buckling of individual sheets prior to feeding, as explained below. The snubbers 10 restrain the stack and hold the top sheet at a proper level for separation and feeding to a pair of feed rollers generally designated 14.

The side frames 6 extend upward at the rear of the machine to two arms 16 which extend out over the stack towards the front of the machine. A support member 18 extends across the stack between the two arms 16 and supports a rotary solenoid RSOL-1 over the center of the stack. A second support member 20 extends across the stack and is supported by the arms 16. A second solenoid SOL-2 is mounted on the support member 20 approximately midway between the two sides of the stack.

The feed rollers 14 consist of a drive roll 22 and a pressure roll 24 both journaled in the side frame members 6. The drive roll 22 is journal'ed in a stationary position at a level so that a sheet extending outward from the top of the stack would lie on the top of the drive roller. The

drive roller is constructed of an outer shell of resilient material mounted on a shaft 26. One end of the shaft 26 extends through one of the side frames 6, and has a drive gear 28 mounted thereon. The gear 28 may either mesh with a corresponding gear on the piece of equipment into which the apparatus is to feed sheets, or may be coupled to some source of power such as an electric motor. The ypressure roller-14 is of the same general construction as the drive roller 22 except that the resilient outer covering is mounted on shaft 30 and is split into three sections thus exposing two portions of shaft 3i) adjacent to the center of the rollers, as seenin FIG. 2. The shaft 30 is slidably mounted in a slot 32 in each of the side frames 6 and is journaled in movable bearings 34. The movable bearings 34 are urged downward by springs 36 pressing against the bearings 34 and retaining members 38. Thus the pressure roller 24 is urged into contact with the drive roller 22.

The shaft of the rotary solenoid R-SOL-l mounted directly above the center of the document stack has a splined shaft 40 extending downward towards the document stack. The shaft 40 is rotatable through an arc of 90 upon actuation of the solenoid. A splined sleeve 42 mates with the splined shaft 40 to be slidable along the length of the shaft. The splined sleeve 42 has a friction disc 44 secured to the bottom thereof to be movable with the sleeve along the shaft. The friction disc 44 has a material 46, such as rubber, secured to the -bottom thereof to be in contact with the top of the stack when the sleeve 42 is moved downward along the shaft 40. The material 46 must be such that it has a coeicient of friction with the material of the sheets'that is greater than the coeicient of friction between successive sheets. The sleeve 42 is moved longitudinally along the shaft 40 by means of a collar 48 surrounding the sleeve 42. The sleeve 42 is loosely joumaled in the collar 48 so that the sleeve is rotatable with shaft 40 upon actuation of the solenoid SOL-1. The collar 48 is held on sleeve 42 bymeans of a flanged collar 50 secured to the sleeve 42 above the collar 48 and a thrust washer 52 between the collar 48 and the friction -disc 44.

The entire friction disc assembly, including the splined sleeve 42, is moved longitudinally along the shaft 40 by means of a pair of projections 54 extending outwardly `from the side of the collar 48 and mating with a pair of elongated slots 56 in the two arms of a yoke mem- -ber 58.`

The yoke member 58 is pivotally mounted on a support member 60 extending downward from the frame arms 16. A pair of pivot pins 62 support the yoke from the support member 60. The yoke member 58 extends past the pivot pins 62 to the pressure rollers 24. The ends of the arms of the yoke 58 are slotted to engage the shaft 30 of pressure roller 24 at the two slots in the resilient cover of the pressure roller 24. At a point Ibetween the pivot pins 62 an-d the shaft 30 the yoke 58 is attached to the actuating arm'64 of solenoid SOL-2 by means of linkage member 66 and pin 68. Actuation of the solenoid SOL-2 produces a pivoting motion 0f the yoke 58 about the pivot pins 62,.thus lowering the friction disc 44 and raising the pressure roller 24. When the solenoid SOL-2 is de-energized the compression spring 36 `forces the pressure roller 24 downward into `contact with the drive roll 22 causing the yoke 58 to pivot about pins 62 and thus raising the friction disc 44. The ern- Ibodiment shown herein utilized solenoids to actuate the various components of the apparatus. It would be within the ability of one skilled in the `art to provide mechanical linkages or a combination of electrical components and mechanical linkages to perform the same function.

Operation A stack of paper or other material is inserted into the document tray by depressing the tray and sliding the paper beneath the friction disc 44 and the snubbers 10. The

- of feeding and the leading edge extends over` the edge of the stack as illustrated in FIGURES `11 and 12.1 The insertion of documents is most easily accomplished when the friction disc is in an `elevated position as illustrated in FIGURES 3 and 4.

Referring now to the schematic FIGURES 3 through 10 and the schematic wiring diagram, FIGURE 11, it is seen that the solenoid SOL-2 is energized upon actuation of the on-of switch SW-l. Actuation of the solenoid SOLI-2 pivots the yoke 58 in a clockwise direction as seen in FIGURE 1 and depresses the friction disc 44 to the position shown in FIGURES 5 and 6. The upward movement of the left-hand portion of the yoke 58 actuates a normally Vopen switch lLS positioned on the support member 60. Closing of the switch ILS energize-S the rotary solenoid R-SOL-l when the friction disc is depressed to the proper feed level. The pressure between the friction disc and the stack is controlled by the springs 8 urging the support plate 4 and the stack upward to the feeding position.

With the lfriction disc 44 in the depressed position and the rotary solenoid actuated, the friction disc rotates the top document 70 as shown in FIGURES 5 and 6. The corners of the document are forced against the comer posts 12 causing the sheet to buckle,` breaking the frictional contact between successive sheets; Normally, only the top sheet is rotated since the coefficient of friction between the friction pad 46` and the sheet is greater than the vcoefficient of friction between two sheets. However, if two sheets are tending to stick together the buckling produced by the corner posts to separate the two sheets reducing the friction between them and insuring that only one sheet is rotated into a feeding position.

Continued rotation of the friction disc 44 through a arc causes the top sheet of paper to rotateto the position shown in FIGURES 7 and 8 wherein the leading edge of the sheet Irestson the feed roller 22 between the feed roller and the pressure roller 24. At this point a normally closed switch 2LS, -rnounted above the pressure disc 44, is actuated by a pin 74 extending upward from the disc 44. The contacts of the switch 2LS are in the circuit to the solenoid SOL-2, thus, upon actuation of the switch the contacts open de-energizing solenoid SOL-2. With the solenoid SOL-2 de-energized the compression springs 36 force the pressure roller 24 down into contact with the document 70 and force the document against the feed roller 22. The feed roller 22 is continuously rotating and immediately drives the sheet 70 forward over a guide tray 72. As the pressure roller 24 is lowered into the drive position the disc 44 is raised away from the document stack permitting the rotated document 70 to be fed by the feed rollers. The downward movement of the lefthand side of the yoke 58 releases switch ILS de-energizing rotary solenoid R-SOL-l permitting the disc 44 to -rotate to its original position under a spring action built into the solenoid.

A second switch 4LS is mounted on the yoke 58 in the same position as the switch 2LS and is actuated by the pin 74 at the Sametime the switch 2LS is actuated.

Actuation of the switch 4LS, upon 90 rotation of they disc 44, closes the normally open contacts of the switch 4LS, energizing relay ICR. Energization of relay ICR closes normally open contacts lCR-l providing a holding circuit for the relay ICR and opens normally closed LCR-2 in the circuitry to solenoid SOL-2. 1 Opening of the contacts ICR-2 prevents the solenoid'SOL-Z from being actuated when the switch 2LS is released by the return of disc 44 to its original position. Both solenoid-s R-SOL-l and SOL-2 are prevented from being energized during the time that the feed rollers are feeding a sheet by the action of a switch 3LS mounted beneath the guide tray 72V and having an actuating arm extending up into the path of travel ofthe sheet 70. When a sheet actuates switch 3LS the normally open contacts of the SLS switch a-re closed energizing relay ZCR. Energization of relay ZCR opens normally closed contacts 2CR-1 in the circuitry to solenoid SOL-2 and opens normally closed contacts 2CR-2 in the holding circuit to relay 1CR. With the relay ICR de-enengized, by opening contacts 2CR-2 in the holding circuit, the entire system is conditioned for the feeding of another sheet upon the release of switch SLS by the sheet 70. When the sheet being fed has passed the switch 3LS the contacts of that switch open deenerlgizing relay 2CR causing the contacts 2CR-1 to revert to their normally closed position thus again energizing solenoid SOL-2. Energization of solenoid SOL-2 pivots the yoke member 58 causing the cycle to be repeated.

A schematic representation of an alternative form of the apparatus is shown in FIGS. 13 through 18. In this form of the apparatus the friction disc 44 rotates the sheet in one direction a distance sufficient to `cause the sheet to buckle against the corner posts 12 and to slide free of the snubbers 10, as seen n- FIG. 13. Counter rotation of the friction disc 44.causes the sheet to rotate back against the snubbers and either slide over the snubbers or abut the snubbers and buckle over them to the original position. The sheet 70 is now above the snubbers 10 and is free to be advanced to the free rollers.

From this position with the single sheet of paper separated from the main stack and Vresting on the snubbers 10 the sheet may be advanced by any number of means such as feed rollers, a gripper bar or a friction drive. In the embodiment shown herein, the friction disc 44 is used to advance the sheet to the

feed rollers

22 and 24. As seen in FIGS. 17 and 18 a simple forward motion of the friction disc 44 will slide the sheet 70 forward between the

rollers

22 and 24 while the main stack is restrained by the corner posts 12. The friction disc 44 is then elevated away from the sheet and the rollers are closed to d-rive the sheet from the stack. Alternative forms for advancing the sheet to the feed rollers or to a gripper bar -may be used. For example, as seen in FIG. 19, when the friction disc 44 is elevated away from the stack a continuously rotating friction belt 72 may be lowered into contact with the top sheet to provide the forward movement of the sheet to the feed rollers. Also, since the sheet is resting on the top of the snubbers 10, it is possible to have a gripper mechanism advance between the sheet and the stack and withdraw the sheet 70. After the friction disc 44 has advanced `sheet 70, as shown in FIGS. 18 and 19, the apparatus is again ready to feed the next sheet. That is, iction dics 44 returns to the position shown in FIGS. 3 and 4 and the entire sequence is repeated.

While the invention has been described with reference to the structure disclosed herein, it is not confined to the details set forth, and this application is intended to cover ysuch modifications or changes as may come within the purposes of the improvements or the scope of the following claims.

I claim:

1. Apparatus for separating individual sheets from a stack for sheet feeding including:

support means adapted to contain a stack of sheets,

a rotatable friction member mounted above the support means and adapted to be moved into and out of contact with the top of a sheet stack on the support means,

means to rotate the friction member when the friction member is in contact with the stack,

and retaining means positioned beside the corners of the sheet stack in interference relationship with rotational movement of the sheets in the stack to produce buckling and separation of individual sheets rotated by the friction member.

2. Apparatus for separating individual sheets from a stack of sheets including:

a sheet stack support plate hav-ing biasing means urging the plate upwards against the weight of the sheet stack,

snubber means positioned above and extending over the corners of the support plate to restrain the top of the stack in a fixed position against action of the biasing means,

a rotatable friction -pad -operatively positioned above the sheet stack and movable into and out of Contact with the -top sheet of the stack,

means to rotate the friction pad when the pad is in contact withthe top sheet of the stack to impart rotational movement to the top sheet,

and corner posts positioned adjacent to the sheet stack in interference relationship with `rotational movement of the sheets in the stack to produce buckling of individual sheets upon rotational movement thereof to thereby separate the top sheet from the remaining sheets on the stack and to remove the top sheet from beneath the snubbers.

3. The apparatus of claim 2 further including means to counter rotate the friction pad to return the top sheet to a position in alignment with the stack above the snubbers and means to impart a forward movement to the top sheet after its return.

4. Sheet feeding apparatus for seriatim sheet feeding from a stack of sheets including:

a sheet stack support plate having biasing means urging the plate upwards against the weight of the sheet stack,

snubber means positioned above and extending over the corners of the support plate to restrain the top of the stack in a xed position against action of the biasing means,

a rotatable friction pad operatively positioned above the sheet stack and movable into and out of contact with the top sheet of the stack,

means to rotate the friction pad when the pad is in contact with the top sheet of the stack to impart rotational movement to the top sheet,

corner posts positioned -adjacent to the corners of the stack in interference relationship with rotational movement of the sheets in the stack to produce buckling of individual sheets on rotational movement thereof to thereby separate the top sheet from the remaining sheets on the stack and to remove the top sheet from beneath the snubbers,

sheet feeding means positioned adjacent to the stack to receive sheets rotated by the friction pad,

and means to operate the sheet feeding means in timed relation to the movement of the friction pad into and out of Contact with the top sheet.

5. Sheet feeding apparatus for seriatim sheet feeding from a stack of sheets including:

a sheet stack support plate having biasing means urging the plate upwards against the weight of the stack,

means to rotate and counter rotate the friction pad when the pad is in contact with the top sheet of the stack to impart rotational movement to the top sheet and to return the top sheet to its original position after separation for subsequent feeding,

corner posts positioned adjacent to the corners of the stack in interference relationship with rotational movement of the sheets in the stack to produce buckling of individual sheets on rotational movement thereof to thereby separate the top sheet from the remaining sheets on the stack and to remove the top sheet from beneath the snubbers,

and sheet feeding means to remove the sheetl from the stack after the sheet has been removed from beneath the snubbers.

6. Sheet feeding apparatus for seriatim sheet feeding from a stack of sheets including:

a sheet stack support plate having a biasing means urging the plate upwards against the weight of the sheet stack,

snubber means positioned above and extending over the corners of the support plate to restrain the top of the stack in a iixed position against the action of the biasing means,

corner posts positioned adjacent to the corners of the stack in interference relationship with rotational movement f the sheets in the stack to produce buckling of individual sheets on 4rotational movement thereof to thereby separate the top sheet from the remaining sheets'on the stack and to remove the top sheet from beneath the snubbers,

a rotational friction member positioned above the support plate and adapted to be moved between an operative position wherein the member contacts the top sheet of the stack and an inoperative position wherein the member is not in contact with the sheet stack,

Ameans to `rotate the friction member whenit is in the operative position to thereby impart rotational movement to the top sheet of the stack,

sheet feed rollers including a drive roller and a pressure roller adapted to vbe separatedl for receiving sheets to be fed and to be brought into contact for feeding sheets inserted between the rollers, said sheet feed rollers being mounted suciently close to the sheet stack so that sheets rotated by the friction member extend between the drive roller and the pressure roller when they are in a separated position,

and control means to synchronize the movement of the friction member between Vthe operative and inoperative positions and the feed rollers between the separator and contact positions.

References Cited by the Examiner UNITED STATES PATENTS 487,514 l2/l892 Briggs 271-21 ROBERT B. REEVES, Primary Examiner.

HADD S. LANE, Examiner.

7/1883 Stuart 271---36 Dedication 3,276,770.-Augustus W. Grz'swod, Rochester, N.Y. SHEET FEEDIN G AP PARATUS. Patent dated Oct. 4, 1966. Dedication filed Sept. 16, 1976, by the assignee, Xero Corporatio/n. Hereby dedicates to the Public the remaining term of said patent.

[Official Gazette Dec'embe?a 7, 1.976.]

Claims

1. APPARATUS FOR SEPARATING INDIVIDUAL SHEETS FROM A STACK FOR SHEET FEEDING INCLUDING: SUPPORT MEANS ADAPTED TO CONTAIN A STACK OF SHEETS, A ROTATABLE FRICTION MEMBER MOUNTED ABOVE THE SUPPORT MEANS AND ADAPTED TO BE MOVED INTO AND OUT OF CONTACT WITH THE TOP OF A SHEET STACK ON THE SUPPORT MEANS, MEANS TO ROTATE THE FRICTION MEMBER WHEN THE FRICTION MEMBER IS IN CONTACT WITH THE STACK, AND RETAINING MEANS POSITIONED BESIDE THE CORNERS OF THE SHEET STACK IN INTERFERENCE RELATIONSHIP WITH ROTATIONAL MOVEMENT OF THE SHEETS IN THE STACK TO PRODUCE BUCKLING AND SEPARATION OF INDIVIDUAL SHEETS ROTATED BY THE FRICTION MEMBER.