US3625507A

US3625507A - Automatic sheet feeder

Info

Publication number: US3625507A
Application number: US869125A
Authority: US
Inventors: Donald B Lucius
Original assignee: Minnesota Mining and Manufacturing Co
Current assignee: 3M Co
Priority date: 1969-10-24
Filing date: 1969-10-24
Publication date: 1971-12-07
Anticipated expiration: 1988-12-07
Also published as: DE2055468C3; CA943985A; FR2066434A5; DE2055468A1; DE2055468B2; GB1300282A

Abstract

An automatic sheet separator and feeder in which an end of the uppermost sheet in a stack of sheets supported on a bottom wall of a tray is lifted over an abutment wall of the tray into contact with a driven member and a shoe is moved to position its toe over the stack of sheets to separate the lifted sheet from the remaining stack of sheets and its sole engaged with a driven member to place the lifted end of the sheet in driving engagement with the driven member to feed the sheet from the stack of sheets.

Description

ilnited States Patent Inventor Donald B. Lucius Bloomington, Minn. Appl. No. 869,125 Filed Oct. 24, 1969 Patented Dec. 7, 1971 Assignee Minnesota Mining and Manufacturing Company St. Paul, Minn.

AUTOMATIC SHEET FEEDER 6 Claims, 7 Drawing Figs.

10.5. C1 27 M33 lint. Cl 1365b 3/20 Field 01 Search 271/26, 20, 30, 33

References Cited Primary Examiner.loseph Wegbreit Attorney-Kinney, Alexander, Sell, Ste1dt& Delahunt ABSTRACT: An automatic sheet separator and feeder in which an end of the uppermost sheet in a stack of sheets supported on a bottom wall of a tray is lifted over an abutment wall of the tray into contact with a driven member and a shoe is moved to position its toe over the stack of sheets to separate the lifted sheet from the remaining stack of sheets and its sole engaged with a driven member to place the lifted end of the sheet in driving engagement with the driven member to feed the sheet from the stack of sheets.

PATENTEDDEC Hen 3625507 SHEET 1 [IF 2 I INVENTOR.

DONALD E. Luc/us BY/f 41 M M WmQwQ/A AT TORNE Y5 AUTOMATIC SHEET FEEDER The present invention relates to an automatic sheet separator and feeder for feeding sheets from a stack thereof over an abutment member seriatim.

The prior art sheet feeders have generally required the use of sheets having uniform consistency to provide the feeding of a single sheet at a time. While this has been satisfactory in some uses, it has not been satisfactory for automatically feeding original documents to a reproducing machine since it is often desired to be able to automatically reproduce original documents of varying size and consistency with a single reproducing machine. Recently it has been found that original documents of varying consistency may be lifted from a stack by contacting the uppermost sheet with a small area of pressure-sensitive adhesive tapeand then lifting the tape and sheet from the stack. To complete the feeding of the sheet some means must be provided for removing the sheet from the pressure-sensitive adhesive tape. In the prior art this has generally been accomplished by the use of a stripper arm or plate pushing the sheet from the adhesive tape as illustrated by U.S. Pat. No. 2,919,129. However, such devices are disadvantageous in that they are generally slow in feeding a plurality of sheets and, more seriously, the sheet is not positively engaged as it is removed from the adhesive tape and the sheet may not be appropriately fed after removal from the tape. Furthermore, when the uppermost sheet is lifted from the stack, a second sheet may be attracted to it by static electricity and may be lifted with it, particularly when the sheets in a stack are light, thin and similar.

It is an advantage of the present invention to provide a fast automatic sheet feeder in which the uppermost sheet is lifted from a stack of sheets and positively engaged and fed as it is removed from the means for lifting it. It is a further advantage of the present invention to provide an automatic sheet feeder in which the uppermost sheet is separated from the remaining sheets in the stack as it is lifted from the stack. It is a still further advantage of the present invention to provide an automatic sheet feeder in which the uppermost sheet in a stack of sheets is lifted from the stack on a piece of adhesive tape and positively engaged and peeled from the adhesive tape and fed along the desired path as the lifted sheet is separated from the remaining sheets in the stack.

The present invention has the advantages desired of an au tomatic sheet separator and feeder and comprises support means including a bottom wall for supporting a stack of sheets and an abutment member over which it is desired to feed sheets seriatim, sheet-lifting means for lifting the end of the uppermost sheet in the stack above the abutment member, driven means extending over the support means abutment member to contact the lifted end of the uppermost sheet, and shoe means positioned below the driven means and having a toe to extend over the stack of sheets for separating the lifted sheet from the stack and a sole engageable with the driven means to place the lifted end of the uppermost sheet in driving engagement with the driven means.

The novel features and advantages of the present invention will become apparent after reading the following description which refers to the accompanying drawings wherein:

FIG. 1 is a top perspective view of an automatic feeder made in accordance with the present invention and assembled in a cabinet, a fragment of which is shown;

FIGS. 2, 3, and 4 are schematic vertical sectional views il' lustrating operation of the automatic sheet feeder through successive positions;

FIG. 5 is a fragmentary vertical sectional view taken generally along line 55 of FIG. I with the cabinet sectioned;

FIG. 6 is a fragmentary vertical sectional view taken generally along line 6-6 of FIG. I with the cabinet sectioned; and

FIG. 7 is a fragmentary top view of the feeder with the cabinet removed.

An automatic sheet feeder made in accordance with the present invention and generally designated 10 is illustrated in the accompanying drawings. It comprises a tray 12 having a bottom wall 14 and an end or abutment wall 16, a tape head 18, a sheet feeding belt 20 and a shoe 22.

The bottom wall 14 of the tray 12 is a rectangular planar plate that is pivotably supported by a shaft 24 that extends parallel to the abutment wall 16 of the tray 12 near the end of the bottom wall I4 farthest removed from the abutment wall 16. The shaft 24 is supported at its ends by a pair of stationary

feeder support castings

25 and 27. The bottom wall 14 provides support for a stack of sheets 26 such as sheets of copy paper or original documents which are to be fed to a reproducing machine from the stack. A compression spring 28 positioned adjacent the abutment wall 16 and spaced to one side of the center of the width of the bottom wall 14 supports the free end of the bottom wall 14 and biases it upward. The abutment wall 16 is planar and extends generally perpendicular to the bottom wall I4. The bottom wall 14 and the abutment wall 16 are normally positioned at an angle to the horizontal so that gravity will aid in moving the stack of sheets along the bottom wall 14 against the abutment wall 16. Along the upper edge of the abutment wall 16 a generally horizontal plateau 30 connects the abutment wall 16 to a downwardly inclined sheet-feeding wall 32 onto which it is desired to feed the sheets 26 from the stack on the bottom wall 14 seriatim.

The tape head 18 comprises a length of pressure-sensitive adhesive tape 34 extending between a pair of spools in a housing 36 over an exposed surface of a support finger, the length of tape being advanced across the finger stepwise as the tape head is moved through successive feeding movements such as disclosed in US. Pat. No. 2,9l9,l29 issued to R. L. Sjostrom. The tape head 18 is supported at the end of an elongated arm 38 with the exposed portion of the pressure-sensitive adhesive tape 34 supported above the bottom wall 14 of the tray 12 generally centrally of the width thereof near the abutment wall 16. The arm 38 is formed as a part of the tape head housing 36 extends into the feeder cabinet 11 where it is formed with a support and driving block 40. A curved link 42 is rotatably supported at one end on a normally stationary pin 43 and its free end is rotatably supported on a pin.44 secured to the tape head support and driving block 40. A straight link 46 formed with a pair of parallel arms one to each side of the curved link 42 and connected by cylindrical sleeves is rotatable about a shaft 47 secured to the support and driving block 40. The shaft 47 extends through one of the cylindrical sleeves of the straight link which is also supported on a shaft 48 passing through the other of its cylindrical sleeves and secured to the stationary support casting 25. The curved link 42, the straight link 46, the tape head support and driving block 40, and the stationary support casting 25 form a four-bar linkage to provide movement of a tape head 18 as will be hereinafter described.

The driving of the tape head four-bar linkage is provided by a crank arm 50 that is rotatable about one end on a shaft 51 extending from the support and driving block 40 and at its opposite end about a pin 53 extending off center from a driving disk 52. The driving disk 52 is formed in two sections which are rigidly secured together by the pin 53 with the crank arm 50 free to rotate about the pin 53 between the two sections. The portion of the driving disk 52 farthest removed from the feeder tray 12 is supported centrally on a driven shaft that extends through the stationary support casting 25 to a one-way spring clutch 57 carried on a driving shaft 55 that is driven by a pulley 59. The pulley 59 is continuously driven by a motor (not shown) through a belt 60 and it drives the shaft 55. A plunger arm 62 of a solenoid 61 normally engages the clutch 57 to prevent its rotation and thereby to prevent rotation of the driving disk 52. Upon actuation, the solenoid 61 retracts the plunger arm 62 to permit the clutch 57 and thereby the driving disk 52 to rotate with the pulley 59 in a counterclockwise direction as viewed in FIG. 5.

The shoe 22 comprises a thin link of a relatively nonfrictional material such as nylon. It is secured at one end by an adjustment link 65 to a rotatably supported hexagonal shaft 66 that extends parallel to the abutment wall 16 of the tray 12 adjacent the lower end thereof. The shoe 22 extends from the hexagonal shaft 66 on the opposite side of the abutment wall 16 from the bottom wall 14 of the tray 12. It extends upward nearly to the upper edge of the abutment wall 16 and then through an aperture 68 formed in the abutment wall 16 and the horizontal plateau 30 to normally lie over the edge of the bottom wall 14 of the tray 12. Along its uppermost portion the shoe 22 is formed with a smooth curved surface herein designated the sole 70 of the shoe and over the bottom wall 14 it tenninates in a generally pointed projection herein designated the toe 72 of the shoe. The shoe 22 is positioned generally centrally of the width of the bottom wall 14 of the tray 12 in alignment with the exposed portion of the pressuresensitive adhesive tape 34.

The sheet feeding belt 20 is made of a high-friction material such as flexible polyurethane and it is supported with its lower run directly above and normally spaced from the sole 70 of the shoe 22 generally parallel to the bottom wall 14 of the tray 12 and the inclined sheet feeding wall 32. The belt 20 extends around and is supported by an idler roller 76 and a continuously driven roller 77. The idler roller 76 is supported by a bracket 79 further over the edge of the bottom wall 14 of the tray 12 than the shoe 22 to position a portion of the sheetfeeding belt 20 over the stack of sheets 26. The driven roller 77 is secured to a shaft 81 that is rotatably supported by the

stationary support castings

25 and 27 and that carries a pulley 83 which is suitably driven from a motor (not shown) through the driven belt 60. A sheet-feeding sponge roller 85 has a segment secured to the driven shaft 81 on each side of the sheetfeeding belt 20 and its peripheral surface contacts the inclined sheet-feeding wall 32 to frictionally drive a sheet down the inclined feeding wall 32. A switch 86 has a leaf spring extending into the path of a sheet fed by the sponge roller 85 to deactivate the solenoid 61 and thereby the driving clutch 57 when the driving disk 52 completes a revolution. The solenoid 61 is, therefore, deactivated when the leading edge of a sheet 26 reaches the sponge roller 85 and reactivated when the trailing edge of a sheet leaves the sponge roller to provide rapid sheet feeding.

At the end of the hexagonal shoe shaft 66, adjacent the stationary support casting 25, is a crank arm or link 87, which extends perpendicularly from the hexagonal shaft 66. A second longer link 88 is pivotally connected to the free end of the short link 87 and extends upward alongside the bottom wall 14 of the tray 12 to the driving disk 52 where it is rotatably con nected off center on a stud 90. The

links

87 and 88 and the driving disk 52 provide the desired movement of the shoe 22 as will be hereinafter described.

The movement of the tape head 18 controlled by its fourbar linkage and the movement of the shoe 22 controlled by

links

87 and 88 are timed or coordinated by the driving disk 52 which is in turn controlled by the solenoid 61 through the clutch 57. Upon each revolution of the driving disk 52 a single sheet 26 is fed off the stack of sheets 26 on the bottom wall 14 of the tray 12 over the abutment wall 16 and down the inclined sheet-feeding wall 32. The movement of the tap head 18 by its four-bar linkage and the shoe by its linkage upon one counterclockwise (as viewed in FIG. revolution of the driving disk 52 is diagrammatically illustrated in FIGS. 2 through 4.

FIG. 2 illustrates the tape head 18 and the shoe 22 in their first or normal rest position. As the driving disk 52 starts its revolution, shoe 22 is rotated out of contact with the stack of sheets 26 through the aperture 68 in the abutment wall 16 to the position illustrated in FIG. 3. At the same time the tape head 18 is first rotated through a short clockwise are (as viewed in FIGS. 2 through 4). The bottom wall 14 of the tray 12 which is urged upward by the compression spring 28 then presses the uppermost sheet in the stack against the rear portion of the tape head housing 36 without contacting the exposed portion of the pressure-sensitive adhesive tape 34. The tape head 18 is then rotated counterclockwise to its second position illustrated in FIG. 3 thereby contacting the exposed portion of the tape 34 against the uppemiost sheet in the stack and rotating it across the sheet 26 to establish firm adhesive connection. in moving to its third position illustrated in FIG. 4, the tape head 18 moves slightly back relative to the tray to move the leading edge of the uppermost sheet 26 from the abutment wall 16 of the tray 12. 1t then rotates clockwise to lift the leading edge of the uppermost sheet above the abutment wall 16 and into contact with the sheet-feeding belt 20. At the same time the shoe 22 is pivoted clockwise to position its toe 72 over the stack of sheets beneath the lifted sheet with the sole 70 of the shoe 22 contacting the sheet to place the lifted edge of the sheet 26 in frictional engagement with the sheet-feeding belt 20 which then peels the lifted sheet from the adhesive tape 34 of the tape head 18 and drives the sheet under the sponge roller 85. As the shoe makes this movement its toe 72 depresses the bottom wall 14 of the tray 12 to separate the stack of sheets from the tape head 18 and thereby to relieve the pressure between the already lifted sheet and the housing 36 of the tape head 18. As the driving disk 52 completes its revolution the tape head 18 and the shoe 22 are moved from their third position illustrated in FIG. 4 back to their first or rest position illustrated in FIG. 2.

A lever 94 is also provided to lift the tape head 18 farther from the bottom wall 14 of the tray 12 than in its normal position when it is desired to manually feed sheets. Lever 94 is supported on a pin 95 for rotation from a rear stop 96 in the automatic feed position to a front stop 97 against which it is rotated when it is desired to manually feed sheets. The lever 94 extends out of the cabinet 11 as illustrated in FIG. 1 to provide ease of switching from automatic to manual feeding. The lever 94 is connected to the tape head 18 by a short cam link 99, and adjustable floating link 100, and a generally horizontal link 101. The horizontal link 101 is pivotably on a pin 102 extending from the stationary support casting 25 and it supports the normally stationary end of the curved link 42 which forms a part of the four-bar linkage for moving the tape head 18. The curved link 42 thus provides lifting of the tape head 18 when the lever 94 is rotated from the rear stop 96 to the front stop 97.

In use, a stack of sheets 26 is placed on the bottom wall 14 of the stray 12 and pushed against the abutment wall 16 under the toe 72 of the shoe 22. When it is desired to feed sheets from the stack the solenoid 61 is activated to retract its plunger arm 62 thereby permitting the clutch 57 to lock the pulley 59 to the driving shaft 55 to rotate the driving disk 52. As the driving disk starts its rotation the shoe 22 moves away from the stack of sheets and the tape head 18 contacts the uppermost sheet 26 and lifts its end above the abutment wall 16 and into contact with the sheet-feeding belt 20. As the sheet is being lifted the shoe 22 is pivoted back over the bottom wall 14 of the tray and the toe 72 of the shoe 22 depresses the bottom wall 14 by contacting the stack of sheets thereby aiding in separating the lifted sheet from the remaining stack of sheets. At the same time the sole 70 of the shoe 22 contacts the sheetfeeding belt 20 and the lifted end of the uppermost sheet thereby causing the sheet to be driven by the belt 20 over the smooth surface of its sole 70. The sheet is then driven between the sponge roll and the inclined sheet-feeding wall 32 to drive it down the inclined sheet-feeding wall 32 as desired. As the leading edge of the sheet crosses under the sponge roller 85 it closes switch 86 thereby deactivating the solenoid 61 to move the plunger arm 62 so that the clutch 57 is disengaged when the driving disk 52 completes its revolution. The tape head 18 and the shoe 22 then return to their normal rest position with the sole 70 of the shoe 22 spaced from the sheetfeeding belt 20. When the trailing edge of the lifted sheet passes over the switch 86 the solenoid 61 is activated, the clutch 57 is engaged and a second uppermost sheet is fed in the same manner as the first sheet.

Having thus described the present invention, what is claimed is:

1. An automatic sheet separator and feeder comprising:

support means including a bottom wall for supporting a stack of sheets and an abutment member over which it is desired to feed sheets seriatim.

sheet-lifting means positioned adjacent said support means abutment member and movable toward and away from a said bottom wall and thus a said stack of sheets for engaging and lifting the end of the uppermost sheet in a said stack above said abutment member,

driven means extending over said support means abutment member to contact a said end of a said uppermost sheet lifted by said lifting means, and

shoe means positioned below said driven means and having a toe to extend over and contact a said stack of sheets for separating a said lifted uppermost sheet from a said stack of sheets and a sole engageable with said driven means simultaneously with said toe contacting a said stack of sheets to press a said lifted end of a said uppermost sheet against said driven means to cause said driven means to drive a said uppermost sheet across said sole.

2. An automatic sheet separator and feeder as recited in claim 1 including timing means for moving said sheet-lifting means and said shoe means to position said sole of said shoe means in engagement with said driven means as said sheet-lifting means lifts a said end of a said uppermost sheet into contact with said driven means.

3. An automatic sheet separator and feeder as recited in claim 1 including linkage means for supporting said shoe means for pivotal movement from a first position wherein said toe overlies a said stack of sheets and engages the uppermost sheet thereof, to a second position spaced from a said stack, to a third position with said toe separating a said lifted uppermost sheet from a said stack of sheets and with said sole placing a said lifted end of a said uppermost sheet in driving engagement with said driven means, and back to said first position.

4. An automatic sheet separator and feeder as recited in claim 3 including means for supporting said bottom wall of said support means for pivotal movement about an axis parallel to and spaced from said abutment member and resilient means fur urging said bottom wall toward contact with said sheet-lifting means, and wherein said toe of said shoe means contacts a said uppermost sheet on said bottom wall in said first and third positions thereof to retain a said uppermost sheet out of contact with said lifting means 5. An automatic sheet separator and feeder as recited in claim 4 wherein said sheet-lifting means comprises a length of pressure-sensitive adhesive tape and tape head means for supporting said length of tape with a portion thereof supported to contact and adhere to a said uppermost sheet for lifting the end of said uppermost sheet in a said stack above said abutment member.

6. An automatic sheet separator and feeder as recited in claim 5 wherein said tape head means includes wall means for contacting a said uppermost sheet on said bottom support wall as said shoe means is moved from said first position to said second position, and said separator and feeder including linkage means for pivotally supporting said tape head means and timing means for moving said sheet-lifting means and said shoe means to contact said supported portion of said tape against a said uppermost sheet as said shoe means is advanced toward said second position and to rotate said tape head to lift the end of a said uppermost sheet into contact with said driven means as said shoe means reaches said third position whereby said shoe means frictionally engages a said lifted sheet with said driven means to peel a said sheet from said supported tape portion to feed a said sheet from a said stack.

Claims

1. An automatic sheet separator and feeder comprising: support means including a bottom wall for supporting a stack of sheets and an abutment member over which it is desired to feed sheets seriatim, sheet-lifting means positioned adjacent said support means abutment member and movable toward and away from a said bottom wall and thus a said stack of sheets for engaging and lifting the end of the uppermost sheet in a said stack above said abutment member, driven means extending over said support means abutment member to contact a said end of a said uppermost sheet lifted by said lifting means, and shoe means positioned below said driven means and having a toe to extend over and contact a said stack of sheets for separating a said lifted uppermost sheet from a said stack of sheets and a sole engageable with said driven means simultaneously with said toe contacting a said stack of sheets to press a said lifted end of a said uppermost sheet against said driven means to cause said driven means to drive a said uppermost sheet across said sole.

4. An automatic sheet separator and feeder as recited in claim 3 including means for supporting said bottom wall of said support means for pivotal movement about an axis parallel to and spaced from said abutment member and resilient means for urging said bottom wall toward contact with said sheet-lifting means, and wherein said toe of said shoe means contacts a said uppermost sheet on said bottom wall in said first and third positions thereof to retain a said uppermost sheet out of contact with said lifting means.

5. An automatic sheet separator and feeder as recited in claim 4 wherein said sheet-lifting means comprises a length of pressure-sensitive adhesive tape and tape head means for supporting said length of tape with a portion thereof supported to contact and adhere to a said uppermost sheet for lifting the end of said uppermost sheet in a said stack above said abutment member.