US3713645A

US3713645A - Sheet separating apparatus

Info

Publication number: US3713645A
Application number: US00137389A
Authority: US
Inventors: P Ferrari; C Farnsworth
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1971-04-26
Filing date: 1971-04-26
Publication date: 1973-01-30
Anticipated expiration: 1990-01-30
Also published as: CA957392A

Abstract

Apparatus to separate individual sheets from the top of the stack as they are fed forwardly. A pair of sheet separator members positioned at the stack corners resist the movement of the sheets to force only the topmost sheets to buckle thereover and be fed therepast. In the case of relatively stiff sheets or those which have a higher beam strength, the sheet separator members are caused to deflect outwardly thereby enabling the stiffer sheets to buckle slightly to overcome the resistence of the movable sheet separator members enabling separation of the topmost sheet from the stack without tearing or otherwise damaging it.

Description

United States Patent n 1 Ferrari et a1.

[54] SHEET SEPARATING APPARATUS [75] Inventors: Patrick T. Ferrari, Fairport', Clinton E. Farnsworth, Rochester, both of [58] Field of Search ..271/61, 21, 36,19, 22, 24, 27l/18,62,25,20, 17

[56] References Cited UNITED STATES PATENTS 3,592,462 7/1971 Fackler ..271/61 X 3,285,601 11/1966 Zeuthen ..271/61 X 2,654,600 10/1953 Ajam et al. ..271/18 R [451 Jan. 30, 1973 Attorney-James J. Ralabate, Donald E. Daley and Melvin A. Klein [57] ABSTRACT Apparatus to separate individual sheets from the top of the stack as they are fed forwardly. A pair of sheet separator members positioned at the stack corners resist the movement of the sheets to force only the topmost sheets to buckle thereover and be fed therepast. In the case of relatively stiff sheets or those which have a higher beam strength, the sheet separator members are caused to deflect outwardly thereby enabling the stiffer sheets to buckle slightly to overcome the resistence of the movable sheet separator members enabling separation of the topmost sheet from the stack without tearing or otherwise damaging It.

4 Claims, 15 Drawing Figures PATENTEUJAH 30 ms -SHEET 10F 4 INVENTORS. FERRARI FARNSWORTH KISHORE N. VORA PATRICK T. CLINTON E.

WM NJ A WM ATTORNEY PATENTEDJAH 30 I975 SHEET 2 [IF 4 FIG. 4

FIG. 2

FIG. 3

SHEET SEPARATING APPARATUS The present invention relates to sheet separating apparatus for insuring that only one sheet is fed at one time from a stack of sheets and, in particular, to a sheet separating apparatus which enables the separation of the topmost sheet advanced from a stack of sheets of varying stiffness commonly used in duplicating machines and the like.

Sheet feeding is normally accomplished by a rotatable shaft equipped with feed rollers frictionally engaging the topmost sheet of a stack of sheets forcing the sheet forward past a separation element commonly referred to as a snubber. The snubber is usually positioned at the leading edge of the stack at or near the corners thereof so as to cause the corners of the topmost sheet to buckle and then snap over separating the topmost sheet from the rest of the stack. Existing sheet separating devices have not been entirely satisfactory in the sense of separating sheets of various stiffnesses normally used, for example, in duplicating machines and the like. In the case of the stiffer sheets the buckling of the sheets is more difficult frequently causing the sheets to tear or be otherwise damaged. One approach in overcoming this problem has been to devise snubbers which have a gate which enables the lighter sheets to buckle thereover but permits the stiffer or higher beam strength sheets to pass through the gate which is forced open as described in copending application Ser. No. 838,780, filed July 3, 1969, and entitled Gated Paper Snubber.

The present invention provides for effective sheet separation which is an improvement over the above mentioned copending application and which is simple and low in cost yet provides for effective separation of individual sheets of different weights and stiffness characteristics without ripping or otherwise damaging the sheets.

It is therefore the primary object of this invention to improve sheet separation in sheet feed apparatus.

A further object of this invention is to improve sheet separating devices capable of separating individual sheets from a stack independently of the stiffness or beam strength characteristics of the sheets.

A further object of this invention is to separate individual sheets fed from the top of a stack of sheets of various stiffnesses without any adjustment to the sheet feed apparatus.

Further objects, features and advantages of the invention pertain to the particular arrangement in structure which may best be understood by the following detailed description of the invention which may be read in connection I with the accompanying drawings wherein:

FIG. I is a plan view of sheet feeding apparatus incorporating sheet separating apparatus according to the present invention;

FIG. 2 is an enlarged plan view of the sheet separating apparatus of the invention;

FIG. 3 is a side view of the corner sheet separating plate member;

FIG. 4 is an isometric view of the corner sheet separating plate member;

FIGS. 5a and 5b illustrate the sequential operation of the sheet separating apparatus during feeding of sheets having a relatively low rigidity or beam strength;

FIGS. 6a through 6c illustrate the operation of the sheet separating apparatus during feeding of sheets having a relatively high rigidity or beam strength;

FIGS. 7a and 7b are side views of the arm lifting apparatus in its lowest and highest positions, respectively;

FIGS. 8a through 8d are enlarged views illustrating sequentially the relationship between the stack and the sheet separating apparatus at different positions of the arm lifting apparatus.

Referring now to FIG. 1 there is shown sheet feeding apparatus incorporating sheet separating apparatus of the present invention. The feeding apparatus comprises spaced

plate members

10 and 12 which serve to support a stack of sheets to be fed one at a time as for example towards the processing stations of a copying machine. The

plate members

10 and 12 are movable toward and away from each other to accommodate different sheet widths through a manually operated sheet adjusting mechanism 15. Sheet adjusting mechanism 15 includes a release member 17 which when depressed by an operator enables the

plate members

10 and 12 to move towards and away to predetermined positions. These positions are accurately determined by the help of a pointer member 19 which is matched with indicator works 21 on the frame indicating different sheet widths.

Plate members

10 and 12 are arranged with

elongated members

23, 25, respectively which have tooth portions engaging a fixed gear 27. By this arrangement when release member 17 is depressed, movement to the plate member 10 causes the gear 27 to rotate and impart an equal movement to plate 12.

In feeding sheets from a stack the topmost sheet in the stack is advanced forward, that is, in the direction of sheet separating assemblies 20 by rotating feed rollers 35. Feed rollers 35 are driven by a rotatable shaft and may be any suitable construction, as for example, described in the above mentioned copending application. The feed rollers act upon the topmost sheet to drive the sheet forward over the second sheet in the stack. The movement of the topmost sheet therefore tends to advance the second sheet. The amount of movement depends upon the surface characteristics of the sheets. In order to insure separation of only the topmost sheet from the stack, the sheet separating assemblies are adapted to apply a restraining force to the topmost sheet as well as to the leading edge of the uppermost sheets of the stack such that only the top sheet is able to buckle therepast. The sheet separating assemblies 30 are symmetrically arranged complementary to each other and it is believed necessary to describe the detail of only one of the assemblies.

Referring now to FIGS. 24 there is shown more clearly the sheet separating assembly which comprises a corner sheet separating plate member 40 which extends diagonally across the corner portion of the stack in overlying relationship therewith. Extending from the plate member 40 are

elongated portions

42 and 44 which have

openings

46 and 48 formed therein respectively. It will be noted that the opening 48 is longer than opening 46 for reasons which become more apparent hereinafter. Also extending from elongated portion 42 is a stop portion 49 for a purpose explained hereinafter. Plate member 40 is supported on a shaft member 51 received in

openings

46 and 48. Shaft member 51 is secured to an arm member 53 which serves to raise and lower the sheet separating assemblies will be explained more fully hereinafter. Extending from the plate member 40 is a resilient finger portion 45 which is located to one side of the center line of the plate member and abuts against the shaft member 51. By this structure the sheet separating assembly is able to pivot or deflect as shown by the dashed line portions of FIG. 2 when a sheet having a high beam strength or rigidity is advanced. The sheet is buckled or snapped from under the plate member 40 as it is forced forward by the feed rolls thereby enabling a sheet even of relatively high rigidity or beam strength to be buckled past the plate member without tearing or otherwise damaging the sheet.

The operation of the sheet separating assembly may be best understood in connection with FIGS. 5 and 6. As shown in FIGS. 5a and 5b the sheet separating assembly is shown acting upon a stack of sheets with a relatively low beam strength or rigidity. In this case the top sheet buckles primarily on the outside edge at x because the beam strength of the sheet is not sufficient to deflect the sheet separating assembly and the sheet corner buckles past the assembly as shown in FIG. 5!). FIGS. 6a through 60 show the sequence of operation in the case of a sheet with a relatively high beam strength or rigidity. As the top sheet is advanced, buckles y and z are formed adjacent to the sheet separating assembly. Due to the relatively high force imparted to the assembly the plate member 40 pivots relative to shaft member 51 against the action of the finger portion 45 causing'the elongated portion 44 to advance moving the plate member 40 relative to the stack corner. in this manner, the buckling of the sheet past the sheet separating assembly is facilitated. it will now be appreciated that the sheet separating apparatus is such that individual sheets may be separated from a stack irrespective of the beam strength thereof. In the past, stiff sheets would tear or otherwise be damaged by the separating plates.

SHEET SEPARATING CONTROL APPARATUS As sheets are fed from the top of the stack, the sheet separating assembly moves downwardly in a generally vertical path until such time as the stack is depleted at which time the assembly is raised for the insertion of a new stack. In order to accomplish this operation, a sheet separating lift apparatus is utilized for effecting movement of the sheet separating assembly so as to remain substantially in continuous operative contact with the corner of the stack during the separating operation. Due to the fact that the plate member 40 deviates slightly from a path in the vertical plane there would be a tendency for it to push against the edge of the stack but this is compensated for by the sheet separating lift apparatus. 7

The sheet separating control apparatus 60 includes the arm member 53 which has a stop portion 65 and a weighted portion 67. A compression spring 69 is wound around shaft member 61 and has one end engaging stop portion 49 and the other end engaging stop portion 65. By this arrangement, a biasing action is maintained on the plate member 40 to maintain a predetermined position of the plate member 40 to the corner of the stack during the separating operation. Arm member 53 is supported in a side plate 69 which is secured to each of the plate members '10 and 12. Plate member 69 is formed with

openings

71, 73 which receive

pin members

75, 77 extending from the arm member 53. It will be noted that the

openings

71, 73 are elongated with a curved contour such that when the arm 53 is raised the

pin members

75, 77 follow along the contour of the openings causing the sheet separating assembly to move in a substantially vertical path. To raise the sheet separating assembly upon insertion of a stack of sheets v to be fed, a camming mechanism including an actuator member 81 serves to actuate a pivot member 83 which rocks a pivot member 85 thereby camming the arm member into a raised position. It will be appreciated that the actuator member 81 can be actuated automatically by an electrical or mechanical input in any suitable fashion as by solenoid actuation to raise the arm member. A coiled spring member 88 is connected to a pin 89 extending from the arm member and to the plate 69 to exert a force on the arm member in a downward direction thereby maintaining engagement of the arm member and sheet separating assembly with the top of the stack of sheets. Also weighted portion 67 on the arm member 53 serves to enhance the downward movement of the arm member. It will be appreciated that where the

plate members

10 and 12 are arranged as sliding tray members relative to a frame that the portion 90 of the pivot member 83 may be contacted by a portion of the frame upon sliding the tray into a surrounding housing thereby causing the arm 53 and sheet separating assembly to raise above a stack of sheets placed on the

plate members

10 and 12.

Referring now to FIGS. 8a through 8d the operation of the sheet separating control apparatus will be understood more easily. FIG. 8a shows the arm 53 in the highest position and FIG. 8d shows the arm member in position with the plate member 40 resting on the top of the stack of sheets to be fed. FIG. 80 shows most clearly the action of the plate member which pivots through an angle alpha on shaft member 51 against the action of spring member 69 when the sheet stack is lowered to a predetermined level. When this occurs, there is a tendency for the plate member 40 to move in towards the stack of sheets. By virtue of the arrangement of the separator plate member on the lift arm member 53 a pivoting action is experienced enabling the sheets to be fed without interrupting the action of the sheet separating assembly to cause separation of the topmost sheet from the stack. FIG. 8d shows the'arm member 53 in its lower most position with the stack of sheets depleted. It will be noted that a separator plate member 40 has pivoted back to its original position relative to the arm,

member 53 because there is no interference with the stack which has been depleted.

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 such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.

What is claimed is:

1. In a sheet-feeding apparatus for feeding the topmost sheet from the stack one at a time comprising a tray for supporting a stack of sheets to be fed,

feed means operative to advance the topmost sheet of the stack forwardly,

deflect and then pivot on an axis parallel to the associated corner of the stack of sheets upon a sheet above a predetermined rigidity being advanced.

2. Apparatus according to claim 1 wherein said third portion is arranged to one side of the centerline of said first portion.

3. Apparatus according to claim 1 wherein said first portion is shaped in the form of a wavelike curve contacting the topmost sheet diagonally to the corner thereof.

4. Apparatus according to claim 1 wherein said support member is connected to a side member associated with said tray, said side member being adjustable to accommodate different width sheets.

Claims

1. In a sheet-feeding apparatus for feeding the topmost sheet from the stack one at a time comprising a tray for supporting a stack of sheets to be fed, feed means operative to advance the topmost sheet of the stack forwardly, separator means positioned adjacent the front corners of the topmost sheet operative to enable buckling therepast of the sheet being advanced, said separator means including first, second and third portions, said first portion overlying a corner area of the topmost sheet, said second portion having spaced apart elements having elongated openings formed therein, a support member extending substantially parallel to the front edge of the topmost sheet received in said openings, said third portion extending from said first portion contacting said support member and being sufficiently resilient to enable said first portion to deflect and then pivot on an axis parallel to the associated corner of the stack of sheets upon a sheet above a predetermined rigidity being advanced.