U.S. patent application number 09/741576 was filed with the patent office on 2002-06-20 for recirculating gripper accumulator having a circular paper path.
This patent application is currently assigned to Pitney Bowes Inc.. Invention is credited to Allen, Robert J., Doery, Michael S., Lyga, Thomas M., Porco, Francesco.
Application Number | 20020074716 09/741576 |
Document ID | / |
Family ID | 24981290 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020074716 |
Kind Code |
A1 |
Allen, Robert J. ; et
al. |
June 20, 2002 |
Recirculating gripper accumulator having a circular paper path
Abstract
A sheet accumulator has a circular paper path and a compact
design. Individual sheets of paper moving along a main linear path
are diverted into the accumulator one by one, and each sheet enters
a gripper having jaws that grip the sheets of paper. The gripper
jaws pull the sheets along the circular paper path until the
gripper returns to a home location, at which point the gripper
stops, opens, accepts another sheet, closes, and makes another
rotation. When the accumulation is complete, the gripper jaws open
to release an accumulated stack of sheets, and a roller is then
engaged to exit the sheets out of the accumulator and into the main
linear paper path.
Inventors: |
Allen, Robert J.; (Danbury,
CT) ; Doery, Michael S.; (Monroe, CT) ; Lyga,
Thomas M.; (Southbury, CT) ; Porco, Francesco;
(Fairfield, CT) |
Correspondence
Address: |
Paul A. Levitsky
Pitney Bowes Inc.
35 Waterview Drive
P.O. Box 3000
Shelton
CT
06484
US
|
Assignee: |
Pitney Bowes Inc.
1 Elmcroft Road
Stamford
CT
06926-0700
|
Family ID: |
24981290 |
Appl. No.: |
09/741576 |
Filed: |
December 19, 2000 |
Current U.S.
Class: |
271/207 |
Current CPC
Class: |
B65H 29/06 20130101;
B65H 2405/54 20130101; B65H 29/51 20130101 |
Class at
Publication: |
271/207 |
International
Class: |
B65H 031/00 |
Claims
What is claimed is:
1. A sheet accumulator comprising: (a) a circular device having an
outer perimeter; (b) a backstop perpendicular to the outer
perimeter of the circular device, extending outward from the outer
perimeter, for stopping sheets of paper each of which enters the
sheet accumulator one by one and registers a lead edge against the
backstop; (c) revolvable gripper jaws having a first open position
and a second closed position, wherein the first open position
defines a mouth adjacent to the outer perimeter of the circular
device, and wherein the closed position is for seizing the lead
edges of all the sheets of paper that have registered against the
backstop whenever an additional sheet registers against the
backstop, and for then pulling all the sheets of paper along a
circular path adjacent to the outer perimeter of the circular
device until the gripper jaws return to a home location where the
gripper jaws move to the first open position; (d) means for exiting
a complete stack of sheets out of the sheet accumulator, after a
predetermined number of sheets has been ungripped by the gripper
jaws; and (e) means for causing the gripper jaws to revolve and to
move between the first open position and the second closed
position.
2. The sheet accumulator of claim 1, wherein the gripper jaws
revolve away from the home location after ungripping the
predetermined number of sheets, and before the complete stack of
sheets exits the sheet accumulator.
3. The sheet accumulator of claim 1, further comprising a
revolvable cam for holding the gripper jaws open against the force
of a spring.
4. The sheet accumulator of claim 3, further comprising a sensing
device, for enabling the cam to stop holding the gripper jaws open
once each additional sheet is detected to have registered against
the backstop.
5. The sheet accumulator of claim 1, wherein the backstop is
revolvable, is coupled to the gripper jaws, and is located between
the jaws so as to form the back throat of the jaws.
6. The sheet accumulator of claim 5, wherein the circular device
comprises a rotatable drum to which the backstop and gripper jaws
are coupled.
7. The sheet accumulator of claim 6, further comprising: (a) a
revolvable and rotatable cam for holding the gripper jaws open
against the force of a spring; (b) a revolvable and rotatable cam
shaft for causing the cam to rotate, the cam shaft having a
constant position relative to the rotatable drum; and a sensing
device, for enabling the cam to stop holding the gripper jaws open
once the additional sheet is detected to have registered against
the backstop.
8. The sheet accumulator of claim 6, further comprising at least
one roller adjacent to the outer perimeter of the circular device,
for forming at least one nip through which the sheets of paper
move.
9. The sheet accumulator of claim 8 wherein the at least one roller
comprises at least one driven roller for holding the sheets of
paper when the gripper jaws are at the home location, and for
driving the complete stack of sheets out of the sheet
accumulator.
10. The sheet accumulator of claim 9, further comprising an
actuator for actuating the at least one driven roller toward the
sheets of paper when the gripper jaw is at the home location,
before the gripper jaws ungrip.
11. The sheet accumulator of claim 10, wherein the circular device
further comprises two rotatable disks having a substantially
similar circumference to the circumference of the rotatable
drum.
12. The sheet accumulator of claim 11, wherein the rotatable drum
is located between the rotatable disks and has the same axis of
rotation as the rotatable disks.
13. The sheet accumulator of claim 12, wherein each of the at least
one driven roller is actuated against the rotatable disks thus
forming one of said at least one nip, and wherein the rotatable
disks otherwise rotate freely and rotate independently of the
rotatable drum.
14. The sheet accumulator of claim 1, wherein the predetermined
number of sheets is a number selected by the user from a range of
numbers.
15. The sheet accumulator of claim 7, wherein the revolvable and
rotatable cam shaft is caused to rotate by a fixed cam rotation
motor, the rotatable drum is caused to rotate by a fixed drum
motor, and the cam rotation motor is separate from the drum motor.
Description
CROSSFERENCE TO RELATED APPLICATION
[0001] Reference is made to Application Ser. No.______ (Attorney
Docket No. F-140), entitled SHEET ACCUMULATOR HAVING A CIRCULAR
FEED PATH, assigned to the assignee of this application and filed
on even date herewith.
TECHNICAL FIELD
[0002] This invention relates to paper sheet accumulators, and more
specifically to a paper sheet accumulator wherein paper sheets are
accumulated individually and then dispensed collectively as a
stack.
BACKGROUND OF THE INVENTION
[0003] Numerous accumulators have been used for accumulating paper
sheets and documents into stacks and then transporting the
accumulated stacks. For instance, Driscoll et al. (U.S. Pat. No.
5,147,092) discloses a flat accumulator comprised of upper and
lower sets of driven elastic belts.
[0004] Although a flat type of accumulator is appropriate for some
applications, its dimensions are too large or bulky for other
applications. This related art cannot conform to the space
limitations and layout of certain machines in which a sheet
accumulator must form a component part. In addition to problems of
size and shape, the related art also has problems when accumulating
paper that does not have normal buckling properties, such as
perforated paper. For example, Miller, (U.S. Pat. No. 5,356,263)
discloses a sheet accumulator in which it is necessary for sheets
of paper to buckle very substantially, which becomes problematic
when the sheet of paper has characteristics inconsistent with
normal buckling (e.g. perforated paper). Another problem
encountered with some of the related art is that the accumulation
process may yield sheets that are out of order or inverted; in
other words, the stack of paper produced may be either face down or
lead-edge trailing relative to the input sheets of paper.
SUMMARY OF THE INVENTION
[0005] The main objective of this invention is to provide a sheet
accumulator for accumulating sheets of paper one by one which
arrive at the sheet accumulator along a main linear paper path, and
for then allowing the stack of accumulated sheets to exit the
accumulator. Another objective of the present invention is to
minimize the amount of space required by the sheet accumulator.
Accordingly, the present invention is a compactly designed sheet
accumulator in which the paper path is circular. This design
conforms to space limitations which other sheet accumulators, such
as flat accumulators, are unable to achieve.
[0006] According to the present invention, individual sheets of
paper moving along a main path enter into the accumulator one at a
time, whereupon each sheet registers its lead edge against a
backstop. Then a set of gripper jaws seizes the lead edge of that
sheet of paper, while also seizing the lead edges of any other
sheets of paper that are already registered against the backstop,
whereupon the jaws pull all of the gripped sheets of paper along a
circular path until the gripper jaws return to a home location. At
the home location, the jaws open so as to accept an additional
sheet of paper. The process repeats itself until a predetermined
number of sheets are accumulated into a complete stack. Once this
complete stack of sheets is registered against the backstop, the
stack is exited out of the sheet accumulator into the main linear
paper path.
[0007] The present invention is designed to offer an economical
sheet accumulator with a compact configuration that allows the
accumulator to fit into spaces where many other sheet accumulators
cannot fit. The present invention is also designed in such a way as
to easily handle paper prone to buckling, such as perforated
paper.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a side view of the sheet accumulator showing the
paper guide, with the gripper jaws at the home location, ready to
accept a sheet of paper.
[0009] FIG. 2 is a side view of the sheet accumulator which has
accepted an initial sheet of paper, with the gripper jaws again at
the home location (the paper guide is again shown).
[0010] FIG. 3 is a side view of the sheet accumulator with the
gripper jaws closed and the sheet of paper being pulled along a
circular path (the paper guide is not shown).
[0011] FIG. 4 is a side view of the sheet accumulator with the
gripper jaws open, at the home location, and accepting an
additional sheet of paper (the paper guide is not shown).
[0012] FIG. 5 is a side view of the sheet accumulator with the jaws
ungripped at the home location (the paper guide is not shown).
[0013] FIG. 6 is a side view of the sheet accumulator with the
ungripped jaws revolved out of the way, enabling the stack of
sheets to be exited out of the apparatus (the paper guide is not
shown).
[0014] FIG. 7 is a front view of the sheet accumulator, with the
jaws ungripped at the home location (the paper guide is not
shown).
DETAILED DESCRIPTION
[0015] As best seen in FIGS. 1 and 2, the sheet accumulator 10 has
gripper jaws 12 which define a mouth 14 for accepting the lead edge
16 of a sheet of paper 18. Each sheet of paper 18 that arrives at
the entry point 19 of the sheet accumulator 10 enters the mouth 14,
and registers against a backstop 20. The gripper jaws 12 are
revolvable, and pull each sheet of paper 18 along a circular paper
path defined by the outer perimeter 22 of a circular device 24, and
the inner perimeter 27 of a circular paper guide 29.
[0016] As best seen in FIGS. 3 and 4, the gripper jaws 12 pull each
sheet of paper 18 as the gripper jaws revolve. When the gripper
jaws 12 are open, they define a mouth 14 which is adjacent to the
outer perimeter 22. While pulling each sheet of paper 18, the
gripper jaws 12 are in a closed position so as to tightly grip the
lead edge 16, as seen in FIG. 3. The mouth 14 opens after it
revolves to a home location 21 where the jaws release the lead edge
16, as seen in FIG. 4.
[0017] The backstop 20, against which each sheet of paper
registers, is perpendicular to the outer perimeter 22 and extends
outward from the outer perimeter 22. As best seen in FIGS. 4 and 5,
sheets 18 enter the sheet accumulator 10 one by one, register
against the backstop 20, and then all the sheets are pulled around
the outer perimeter 22. As seen in FIG. 6, a complete stack of
sheets 25 will exit the sheet accumulator 10 after a predetermined
number of sheets have been ungripped by the gripper jaws 12.
[0018] Further description of the best mode for operating the
present invention can be seen in FIG. 7, which is a view from the
front of the sheet accumulator 10, instead of a side view as in
FIGS. 1-6. In FIG. 7, the mouth 14 is at the home location 21 and
is open, as in FIGS. 1, 2, 4, and 5. FIG. 7 shows that the circular
device 24 comprises a rotatable drum 26 and two rotatable disks 28,
the mouth 14 being adjacent to the rotatable drum 26 and not
adjacent to the two rotatable disks 28. The rotatable drum 26 and
the two rotatable disks 28 all have substantially the same
circumference as each other.
[0019] The mouth 14 of the gripper jaws 12 is opened and closed by
movement of the inner jaw 30 only, while the outer jaw 34 remains
stationary relative to the outer perimeter 22. The inner jaw 30 is
attached to a pivot member 32, and the inner jaw 30 moves toward
the outer jaw 34 by pivoting around the pivot member 32. This is
best seen in FIGS. 3 and 4 where the mouth 14 is closed and open,
respectively. The fact that the outer jaw 34 of FIG. 4 is pivoted
with respect to the outer jaw 34 of FIG. 3 is easily seen with the
help of the reference box 35. The inner jaw 30 is also attached to
a spring 36 which urges the inner jaw 30 to pivot toward the outer
jaw 34 and thus to close the mouth 14. The inner jaw 32 pivots away
from the outer jaw 34, against the force of the spring 36, when a
cam 38 forces the inner jaw 32 away from the rotation axis of the
cam 38. The cam is attached to a cam shaft 40, as shown in FIG. 7,
which rotates the cam 38 so as to open and close the mouth 14.
[0020] The sheet accumulator 10 operates in a repetitive manner,
accumulating a stack of sheets 25 by accepting sheets one by one
into the mouth 14 defined by the gripper jaws 12. Each sheet 18
stops when it hits the back throat 42, the back throat being the
only surface of the backstop 20 that comes into contact with each
sheet of paper 18. The back throat 42, the gripper jaws 12, the cam
38, the spring 36, the cam shaft 40, and the rotatable drum 26 are
all coupled together and move in unison around the central drum
shaft 44. The gripper jaws 12 grip a successively greater number of
sheets until a predetermined number of sheets has revolved around
the circular device 24 in the rotation direction 46. The gripper
jaws 12 will always open and then close at the home location,
except after a complete stack of sheets 25 is released, in which
case the gripper jaws 12 will revolve away from the home position
while remaining open, as best seen in FIG. 6.
[0021] In the embodiment of this sheet accumulator 10 shown in
FIGS. 1-6, a sensor 48 detects when a sheet has registered against
the backstop 20, so that the cam will then close the mouth 14. This
sensor 48 can be situated at various places, such as near the trail
edge 50 of the registered sheet of paper 18.
[0022] The rotatable disks 28 are free to rotate independently of
the rotatable drum 26, the latter rotation being powered by a drum
motor 51. The driven rollers 52 shown in FIGS. 1-6 form disk nips
54 with the rotatable disks 28, but do not form any nip with the
rotatable drum 26 which rotates at angular velocities that differ
from the angular velocities of the rotatable disks 28. The driven
rollers 52 cause the rotatable disks 28 to rotate, the rotatable
disks 28 otherwise rotating freely. The driven rollers 52 hold each
sheet 18 securely in place whenever the mouth 14 is opened, by
being actuated against the rotatable disks 28. The driven rollers
52 will be rotated and activated by a roller motor/actuator 56 when
a complete stack of sheets 25 has been accumulated, so as to rotate
the complete stack 25 away from the circular device 24 and into a
set of takeaway rollers 58.
[0023] Because the cam shaft 40 is coupled to the rotatable drum
26, the cam shaft 40 will revolve whenever the drum motor 51 causes
it to revolve via drum gears 53. However, the cam shaft 40 also
requires an additional motor 60. The cam shaft 40, in addition to
revolving around the central drum shaft 44, will also rotate so as
to open and close the gripper jaws 12, and that rotation is powered
by a separate cam rotation motor 60. Thus, this sheet accumulator
requires at least three motors: the drum motor 51, the roller
motor/actuator 56, and the cam rotation motor 60. Of course, any
other driven rollers, for example the takeaway rollers 58, may be
powered by supplementary motors.
[0024] As described thus far, the process by which collations are
built can be thought of in two phases: a build phase and an exit
phase. The build phase is a repetitive process involving a
predetermined number of revolutions of the gripper jaws 12. The
exit phase involves the gripper jaws 12 moving out of the way just
once, so that the complete stack of sheets 25 can exit the
apparatus via the takeaway rollers 58.
[0025] During the build phase, the cam rotation motor 60 enables
the cam 38 to be rotated whenever the gripper jaws 12 are at the
home location, utilizing concentric shafting, cam motor gears 62
coupled to an electromagnetic clutch 64, central cam shaft gears
66, and peripheral cam shaft gears 67. When the gripper jaws 12 are
at the home location, the rotatable drum 26 is stationary, the
electromagnetic clutch 64 is deenergized, and the cam shaft 40 is
driven independently of the central drum shaft 44. Then, when the
cam 38 rotates so as to close the gripper jaws 12, the
electromagnetic clutch 64 is energized causing the cam shaft 40 and
the central drum shaft 44 to rotate as one. This in essence
preserves the relative configuration of the cam and the main
drum.
[0026] It is noteworthy that the order in which each stack of
sheets 25 is built preserves the order in which each sheet of paper
18 is generated and presented to the accumulator 10. For instance,
if a collation of four sheets is generated and presented face up,
the accumulator 10 will ensure that the stack of sheets 25 upon
completion will have the sheets in the identical order and face
up.
[0027] Certain changes may be made in the above construction
without departing from the scope of the invention, as will be
understood by those skilled in the art, and it is intended that all
matter contained in the above description or shown in the
accompanying drawings shall be interpreted as illustrative and not
in a limiting sense.
* * * * *