U.S. patent number 3,727,910 [Application Number 05/137,390] was granted by the patent office on 1973-04-17 for sheet separator control apparatus.
This patent grant is currently assigned to Xerox Corporation. Invention is credited to Kishore N. Vora.
United States Patent |
3,727,910 |
Vora |
April 17, 1973 |
SHEET SEPARATOR CONTROL APPARATUS
Abstract
Apparatus to control the operation of corner separator members
operating to separate individual sheets from the top of the stack
as they are depleted. 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.
The separator members, each mounted on an arm, move in a generally
vertical path as the sheets are fed from the top of the stack. As
the stack height decreases a biasing action enables pivotal
movement of the separator member on the arm as contact is made with
the stack edge near the bottom. A camming mechanism serves to raise
the arm and separator member upwardly upon insertion of a new stack
by mechanical actuation or an electrical signal.
Inventors: |
Vora; Kishore N. (Rochester,
NY) |
Assignee: |
Xerox Corporation (Stamford,
CT)
|
Family
ID: |
22477208 |
Appl.
No.: |
05/137,390 |
Filed: |
April 26, 1971 |
Current U.S.
Class: |
271/19; 271/21;
271/170 |
Current CPC
Class: |
B65H
3/54 (20130101); B65H 3/56 (20130101); B65H
3/06 (20130101) |
Current International
Class: |
B65H
3/56 (20060101); B65H 3/54 (20060101); B65H
3/06 (20060101); B65h 003/56 () |
Field of
Search: |
;271/61,21,36,19,22,24,18,62,25,20,17 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Blunk; Evon C.
Assistant Examiner: Stoner, Jr.; Bruce H.
Claims
What is claimed is:
1. In a sheet-feeding apparatus for feeding a stack of sheets in
which the topmost sheet of the stack is advanced past sheet
separator means, the improvement comprising
sheet separator means positioned adjacent the front corners of the
topmost sheet,
said sheet separator means including a sheet separator member
overlying a corner area of the topmost sheet,
a support member pivotally supporting said sheet separator member
adapted to move at substantially right angles to the stack and said
sheet separator member in substantially a vertical direction as
sheets are being fed,
said support member having a stop portion, extending therefrom,
spring bias means connected to said stop portion and said separator
member to urge said separator member into a predetermined
relationship therewith until such time as said separator member is
carried against at least a partially depleted stack which causes
pivotal movement of said sheet separator member downwardly against
the action of said spring bias means so that the separator member
is not urged against the edges of the stack,
said support member is connected to an arm member movably supported
by a plate member, said plate member having elongated openings
formed therein and receiving pins extending from said arm member
and slidable therein, and camming means for raising said arm member
along a predetermined path constrained by the movement of the pins
in said elongated openings,
spring means connected to said arm member and the plate member to
urge said arm member downwardly into contact with a stack to be
fed.
2. Apparatus according to claim 1 wherein said camming means is
responsive to mechanical actuating means.
3. Apparatus according to claim 1, wherein said camming means is
responsive to an electrical signal.
4. Apparatus according to claim 1, wherein said arm member includes
a weighted portion to facilitate lowering thereof.
Description
The present invention relates to sheet separator control apparatus
for insuring continuous stripping of single sheets one at a time
from a stack of sheets and, in particular, to controlling the
movement of sheet separating members which enables the separation
of the topmost sheet from a stack of sheets 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 separating
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 as described, for example, in U. S. Pat. No. 3,476,381.
Existing sheet separating devices have not been entirely
satisfactory in the sense of moving the separating element relative
to the stack of sheets being fed in the sense that a proper
position must be maintained continuously during the sheet feeding
operation irrespective of the stack height.
The present invention provides for continuous effective sheet
separation by sheet separator control apparatus 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
separation of sheet material fed from a stack.
A further object of this invention is to improve the control of
sheet separating devices capable of separating individual sheets
from a stack used in duplicating machines or the like.
A further object of this invention is to control the movement of
separating devices for separating individual sheets fed from the
top of a stack of sheets as the stack is unloaded and then
reloaded.
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 with the accompanying drawings
wherein:
FIG. 1 is a plan view of sheet feeding apparatus incorporating
sheet separating apparatus and sheet separator control 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. 5( a) and 5( b) illustrate the sequential operation of the
sheet separating apparatus during feeding of sheets having a
relatively low rigidity or beam strength;
FIGS. 6(a) through 6(c) illustrate the operation of the sheet
separating apparatus during feeding of sheets having a relatively
high rigidity or beam strength;
FIGS. 7(a) and 7( b) are side views of the sheet separator control
apparatus in its lowest and highest positions, respectively;
FIGS. 8( a) through 8( d) are enlarged views illustrating
sequentially the relationship between the stack and the sheet
separating apparatus at different positions of the sheet separator
control apparatus.
Referring now to FIG. 1 there is shown sheet feeding apparatus
incorporating sheet separating apparatus and sheet separator
control 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 30 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 copending application Ser. No.
838,907, filed July 3, 1969, entitled Sheet Retaining Apparatus.
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 upper most 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. 2-4, 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 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. 5(a)
and 5(b) 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(b). FIGS. 6( a) through 6(c) 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 SEPARATOR 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 separator control apparatus is utilized for
effecting movement of the sheet separating assembly so as for it to
remain substantially in continuous operative contact with the
corner of the stack during the separating operation. Due to the
fact that the path of plate member 40 deviates slightly from a
position at right angles to the stack edge there would be a
tendency for it to push against the edge of the stack as the stack
is depleted but this is compensated for by the sheet separator
control apparatus of the invention.
The sheet separator 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 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. 8(a) through 8(d) the operation of the sheet
separator control apparatus will be understood more easily. FIG.
8(a) shows the arm 53 in the highest position and FIG. 8(d) shows
the arm member in position with the plate member 40 resting on the
top of the stack of sheets to be fed. FIG. 8(c) shows most clearly
the action of the plate member which pivots through an angle on
shaft member 51 against the action of spring member 70 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. 8(d) 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.
* * * * *