Note: Descriptions are shown in the official language in which they were submitted.
CA 02189669 2002-04-11
1
APPARATUS AND METHOD FOR SORTING PACKAGES OR L1?TTERS AND
OTHER LIgE OBJECTS
Technical Field of the Invention
This invention relates to an apparatus for automatically feeding objects
such as packages or letters at a high speed onto a sorting line.
Background of the Invention
The use of sorting machines to separate packages along an automated
system is known. Such systems are useful in sorting a large number of packages
for
delivery to a number of different regions, such as zip code areas. Under the
control
of a computer or programmed logic controller, the packages are identified or
coded as
they enter the system and may then be tracked for output at a chute or bin
corresponding to the coded information.
' Many deliveries are made in standardized letters of a specified
size (such as 9-1/z x 12-1/z inches). These envelopes are often called
"flats" or "flat letters" in the shipping industry. T'he size and
construction of the flat letters is standardized so that they, may
be handled and sorted quickly. Because coded data is imprinted on the
w0 95132138 ~ ~ PCrIUS95106911
a
sides of these envelopes concerning their destination, it is preferable
that the envelopes be sorted such that the information on the flats
may be read by a scanner as the flat letters move along a sorting
line.
U.S. Patent No. 4,838,435 to Alexandre and U.S. Patent
No. 3,757,942 to Gunn each disclose envelope sorters which allow
sorting in a generally upright position so that coded information may
be read on the envelopes as they proceed along a line. The patent to
Alexandre discloses a conveyor assembly for processing photograph
envelopes. The assembly includes a lower, horizontal conveyor belt
for moving the envelopes along the line and two guide rails which
extend above and beside the lower conveyor for preventing the
envelopes from falling. In this manner, the envelopes are delivered
in a substantially vertical orientation. A variety of different sorting
modules are provided along the conveyor for separating out
packages which are too long, too thick, or unmarked. Each of these
sorting modules includes an opening in one guide rail and a flap built
in as part of the other guide rail. When a reject envelope approaches
the sorting module, the flap is operated to reroute the envelope out
through the opening in the other guide rail.
The manner of feeding the letters into the sorting
system, known as the feeding mechanism, of Alexandre, dumps
envelopes, standing up or lying down, on a receiving belt consisting
of a horizontal endless belt. At the output of this receiving belt, the
envelopes are suctioned onto a vertical, air-permeable conveyor belt
by a vacuum which is located on the other side of the vertical belt.
The envelopes are then fed into the horizontal conveyor belt between
the two guide rails so that the envelope is maintained in the
substantially vertical orientation.
Gunn discloses an envelope sorter having a lower,
horizontal conveyor belt for supporting the bottom of the envelope
and an upper, substantially vertical conveyor belt supporting the top
of the envelope. The system relies solely on gravity for keeping the
envelopes on the conveyors, and therefore the envelopes are
transported down the line in an orientation which is substantially
w0 9,5132138 ~ ~ PC'TI13S95I06911
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vertical, but slightly tilted from vertical. A movable sorting bin at
the end of the conveyor belt moves responsive to a bar code reading
on the envelopes so that the envelopes may fall from the end of the
belts into a proper chute. The feeding mechanism of Gunn provides
envelopes in a slanted orientation, approximately 45° to vertical,
down to a roller. The roller then feeds the envelopes, one at a time,
onto the two conveyor belts.
Several problems exist with these prior art feeding
mechanisms. The large number of the stiffened cardboard flats that
are used in the industry today, along with the need for nationwide or
even worldwide shipping in one night, requires that the sorting
mechanism, and therefore the feeding mechanism, work at extremely
high speeds. The prior art designs are not developed so as to work
at this high volume of output with the semi-rigid flats.
The feeding mechanism of Gunn is designed for flexible
envelopes which can be easily turned and rolled onto the conveyor
by the roller of that system. The roller could be inadequate for
feeding stiffened cardboard flats. Moreover, the feeding mechanism
of Glcnn does not insure exact positioning of the envelopes on the
conveyor belt, but instead drops envelopes on the conveyor belt as
the roller reaches the end of the envelope. If envelopes are not
positioned exactly the same in the slanted feeding trough of Gunn,
the envelopes could not be fed into the conveyor system in a
consisteilt manner. The feeding mechanism of Alexandre, on the
other hand, has its own problems. The suction conveyor of that
system may drop an envelope in any orientation onto the horizontal
conveyor. There is also no provision in Alexandre for timed entry
of the envelopes into the sorting system. Instead, the feeding
mechanism just drops the envelopes randomly into the conveying
system.
There is a need in the art for a feeding mechanism
.. which can more efficiently deposit a large number of packages on a
high-speed sorting system. This feeding mechanism preferably
would have a more timely and accurate manner of depositing the
packages than the systems currently offered.
CA 02189669 2001-07-16
4
Summary of the Invention
Accordingly the present invention seeks to provide an improved apparatus
and method of sorting objects.
Further the present invention seeks to provide an improved method of
depositing items into a moving conveyor system.
The invention in one broad aspect pertains to an apparatus for transporting
and sorting substantially planar individual items along an item travel path,
the items
having opposing upper and lower edges. The apparatus comprises a lower
conveyor
travelling at least partially parallel to and adjacent to the item travel path
and for
supporting the lower edge of each of the items and an upper conveyor
travelling at least
partially parallel to and adjacent to the item travel path, the upper conveyor
for
supporting the upper edge of each of the items with the upper and lower
conveyors
combining to urge the items along the item travel path. A plunger separate and
distinct
from the upper and lower conveyors has a travel path intersecting the item
travel path,
the plunger located intermediate the lower and upper conveyors and configured
for
ejecting an item from the item travel path by a pushing action.
The invention further comprehends a method of sorting individual items
moving along an item path comprising the steps of providing a guide rail along
the item
path, the guide rail being comprised of movable segments, each of the segments
configured in a first position to prevent the items from falling from the item
path as the
items move along the item path and movable to a second position where an item
may
be removed from the item path, placing the item on a movable location along
the item
path, scizsing .output data on the item as the item moves along the item path.
the output
data corresponding with a certain movable segment of the guide rail and moving
the
certain movable segment to the second position and substantially
simultaneously ejecting
CA 02189669 2001-07-16
the item from the item path responsive to the location on the movable track
arriving
substantially at the certain segment.
Still further the invention pertains to a guiding and ejecting module for
use on a line for sorting individual items, the line having a path along which
the items
5 are transported. The module comprises at least one movable guide for
maintaining the
items on the path, the guide configured in a first position to prevent the
items from
falling off a first side of the path as the items move along the path and
movable to a
second position where an item may be removed from the first side of the path
and a
plunger for pushing an item off the first side of the path when the guide is
in the second
position. More particularly, there is provided an ejection module for use in
sorting
individual items travelling along the path, which includes a jaw which
discourages
movement of the items in a transverse direction relative to the path, the jaw
being
configured to move away from around the item as the plunger pushes the item
from the
path.
Still further the invention comprehends an apparatus for transporting and
sorting substantially planar individual items having upper and lower edges,
the apparatus
comprising conveyor means for conveying the planar items in a substantially
vertical but
slightly inclined orientation by use of a conveyor supporting the lower edge
and the
upper edge leaning against a substantially vertical surface and plunger means
for ejecting
the planar items away from the conveyor such that the item is ejected from the
apparatus with its upper edge leading its lower edge.
Other aspects, features and advantages of the present invention will become
apparent upon consideration of the following detailed description of the
invention when
taken in conjunction with the drawing and the appended claims.
CA 02189669 2001-07-16
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Brief Description of the Drawings
Fig. 1 is a schematic of two automatic sorter systems embodying the
invention.
Fig. 2 is a typical flat letter, known in the industry, which may be sorted
by the automatic flat sorters of Fig. 1.
Fig. 3 is a side view of a feeding mechanism embodying the invention.
Fig. 4 is a top view of the feeding mechanism of Fig. 3, with parts broken
away to show interior detail.
Fig. 5 is a top view of an alternative embodiment of a feeding mechanism
embodying the invention.
Fig. 6 is a side view of an ejection module for use in the automatic sorting
system of the invention, with the ejection module in a closed, or travel,
position.
Fig. 7 is a side view of the ejection module of Fig. 6, with the ejection
module in an opened, or ejection, position.
Fig. 8 is a front view of two ejection modules such as are shown in Figs.
6 and 7, with one of the ejection modules opened and the other closed.
Fig. 9 is a side view of an alternate embodiment of an ejection module
embodying the invention, with the ejection module in a closed, or travel,
position.
Fig. 10 is a side view of the ejection module of Fig. 9, with the ejection
module in an open, or ejection, position.
Fig. 11 is a side view of an alternate embodiment of a feeding mechanism
embodying the invention.
Fig. 12 is a rear view of the feeding mechanism of Fig. 11, with parts
removed for detail.
Fig. 13 is a front view of the vacuum port for use with the feeding
mechanism of Fig. 11.
"4Y0 95132138 PCTIUS95106911
nPta;lP.t nP~~rintinn of the Embodiment
Referring now in more detail to the drawing, in which
like numerals represent like parts throughout the several views, Fig.
1 shows two automatic sorting systems 10. The two sorting systems
are similar in configuration and each include a path 12, the two
paths being placed in substantially parallel, back-to-back relationship
in the figure. The paths 12 each include feed stations 16 for
depositing individual items or objects to be sorted in the system 10.
10 A data scanner 18 is located just past the feed stations 16 on each of
the paths 12 and a plurality of ejection modules 20 are located past
the scanners at spaced intervals along each of. the paths 12.
Discharge chutes 22 extend outwardly and downwardly from each of
the ejection modules 20 to guide ejected objects to separate bins 24.
Briefly described, objects fed from the feed stations travel down the
path I2 while data are scanned by the scanner 18, and finally are
ejected at one of the ejection modules 20 into a chute 24, the
particular ejection module determined by the scanned data. For ease
of description, hereinafter the design and operation of only one
system 10 will be described.
Each system 10 disclosed in the drawings is designed to
sort typical flat letters in the shipping industry. Such a flat letter 30
is shown in Fig. 2. The flat letter 30 is typically made at least
partially of cardboard, and is designed to receive a specified
thickness or weight of paper therein while maintaining a semi-rigid
formation. The flat letters 30 define two opposing primary planar
surfaces 3I, 32. One planar surface 31 includes a destination code
33, such as a bar or other code, which is encoded and may be placed
on the flat letter by delivery and service personnel. Adjacent to the
destination code 33 is an address label 34, which may be applied by
the customer. The letters have a typical size of 9 I/2 inches height
(designated by the letter A in Fig. 2) by I2 I/2 inches length
(designated by the letter B in Fig. 2). The flat letter defines an
upper edge 35, a lower edge 36, a leading edge 37, and a trailing
edge 38.
W095132138 ~ ~ PCT/US95I069I1
Fig. 3 discloses a side view of a feeding mechanism 40
such as is located at each of the feed stations I6 along each automatic
sorting system 10. The feeding mechanism 40 is used to deposit the
flat letters 30 on the path 12 such that their primary planar surfaces
3I, 32 are substantially vertical. With reference to Fig. 3, the
feeding mechanism 40 includes an upper conveyor 42 and a lower
conveyor 44. The conveyors 42, 44 are synchronized and include
separating cleats 46 along their length.
The upper and lower conveyors 42, 44 work together to
IO contain the upper and lower edges 35, 36 of the flat letters 30. Air
injectors 48 (see Fig. 4) are included at the discharge end of the
conveyors 42, 44, for blowing the flat letters 30 off the end of the
feeding mechanism 40 onto the path 12. A feeding slot 50 is
included at the leading end of the feeding mechanism 40 for
depositing the flat letters 30 into the feeding mechanism 40.
An alternate embodiment of a feeding mechanism 140 is
shown in Fig. 5. In this embodiment, conveyors 142, I44 extend
substantially vertical and the flat letters 30 are positioned
therebetween in a substantially vertical orientation. Air injectors 48
(not shown) are preferably used on this embodiment as well, and are
located above and below the letters 30. In operation, the conveyors
142, 144 contain the leading and trailing edges 37, 38 of the flat
letters 30.
Referring back also to Fig. 3, to properly understand
the function of the feeding mechanism 40, the movement along the
path 12 downstream of the feeding mechanism must first be
explained. The path 12 includes a lower path conveyor 60 and an
upper path conveyor 62. The lower path conveyor 60 defines a
substantially horizontal support surface in the form of a belt 64. In
addition, the lower conveyor belt 64 preferably includes transverse
cleats 66 which separate positions 68 on the lower conveyor belt 64
for receiving individual flat letters 30. The upper conveyor 62
defines a substantially vertical support surface in the form of a belt
69. The upper and lower conveyors 62, 60 together define the
substantially straight path 12 along which the flat letters 30 travel
W09~132138 ~ ~ PCT1US95l06911
9
prior to being ejected from the path. As can be seen in Fig. 3, the
lower conveyor belt 64 supports the lower edge 36 of the flat letters
30, while the upper edge 35 leans against the upper conveyor belt
69.
Operation of the feeding mechanism 40 may be
described as follows. The flat letters 30 are fed through the feeding
slot 50 into the feeding mechanism 40. The flat letters 30 preferably
are fed with the destination code 33 in an orientation such that when
the flat letters are placed in the path, the code is accessible to the
scanners I8 when the flat letter 30 moves down the path 12. Thus,
as Fig. 4 is viewed, the flat letters 30 are fed with the planar surface
31 facing the right. The upper and lower feeding conveyors 42, 44
are driven by a high speed stepping motor (not shown), such as is
known in the industry. After the flat letters 30 are fed into the slot,
the letters are caught between a corresponding pair of cleats 46 on
the upper and lower feeding conveyors 42, 44 of the feeding
mechanism 40. The upper and lower feeding conveyors 42, 44
move forward in synchronicity with one another.
When the feeding conveyors 42, 44 have moved a flat
letter 30 into a position to be inserted into the line, the two feed
conveyors 42, 44 move rapidly forward to release the flat letter 30
and then stop. Substantially simultaneously to this stopping, a series
of two or more air jets from the air injectors 48 apply air pressure
to the flat letter 30 so that the letter may rapidly enter the stream of
the moving path 12 between two cleats 66 of the lower conveyor belt
64. If a letter is already in the location 68 on the lower conveyor
belt 64, a presence photocell 70 will detect its presence and will
inhibit the feeding mechanism 40 from operating until a space is
available. Multiple feeding mechanisms 40 may be employed to
_ 30 match the capacity of the automatic sorting system 10.
It should also be understood that a mechanical "picking"
device such as is known in the art could be used in combination with
or in replacement of the air blasts to facilitate transfer of letters
from the feeding conveyors into the sorting path.
WO 95f32138 ~ ~ ~ PCT/US95/06911
Alternative Embodiment of the Feeding Mechanism
An alternative embodiment of a feeding mechanism 240
is set forth in Figs. 11-13. Briefly, the feeding mechanism 240
indexes a number of flats 30 down a flat feeding line 242, where the
5 flats are individually grabbed by a grasping mechanism 244 and
placed on a flat sorting line, such as on the lower conveyor 60 of the
path 12. The grasping mechanism 244 uses suction ports in the folm
of vacuum cups 246 to selectively take hold of the flats and move the
flats from the feeding line 240 to the path 12 where they are released
10 between two cleats 66 on the lower conveyor 60.
The feeding line 242 includes a slipping surface 248 for
receiving a number of flats 30 aligned in a vertical direction. The
slipping surface 248 ends sharply so as to form a substantially
vertical chute 249 extending downward from the slipping surface
248. Preferably, the chute 249 extends in the direction of and ends
near the lower conveyor 60. The upper conveyor 64 may be located
on the chute 249, or may be located downstream of the chute on the
same side of the path 12.
A pusher carriage 250 is configured to bias the flats 30
in the direction of the chute 249 and to maintain the flats in the
vertical orientation. The pusher carriage 250 is biased by a spring
252 such that the carriage maintains a constant pressure against the
flats 30, continually pushing them to the left in Fig. 11. A retaining
idler roller 254 is positioned against the end of the row of flats 30 in
a position just beyond the edge of the slipping surface 248.
Fig. 11 discloses a side view of the grasping mechanism
244, which is used to move the flats 30 from the feeding line 242 to
the path 12. In the embodiment shown, the grasping mechanism 244
includes a vacuum timing belt (such as a cog belt) 260 set to rotate
about a rotatably supported drive pulley 262 and two rotatably
supported idler pulleys 264, 266. As can best be seen in Fig. 12,
three sets of two vacuum cups 246 are located transversely across the
timing belt 260, and spaced equidistantly around the belt 260. The
vacuum timing belt 260 is driven by the drive pulley 262, which is
rotated by a drive motor 270 via a vacuum timing belt 272.
W095I32138 s ~ PCTIIJS95/06911
11
The vacuum cups 246 are supplied with intermittent
suction by a rotating port and suction system 278. The rotating port
and suction system 278 includes a constant source of vacuum 280
leading from a stationary port 282. The stationary port 282 includes
a vacuum timing port 284, consisting of a hole which extends
through the stationary port 282 and forms a manifold 283 along the
face of the stationary port, as can best be seen by Fig. 13.
Preferably, the manifold 283 of the vacuum timing port 284 extends
approximately one third around the face of the stationary port 282.
A rotating disc 286 is mounted for revolving motion
relative to the face of the stationary port 282, as can best be seen in
Fig. 12. The rotating disc 286 includes three rotating ports 288.
Flexible hoses 290 extend from the rotating ports 288 to the three
pairs of vacuum cups 246 on the vacuum timing belt 260. The
rotating disc 286 is driven by a motor 294 via a vacuum timing belt
292 and is rotatably supported by a bearing surface as known in the
art. The operation of the motor 294 and the motor 270 for the
vacuum timing belt 260 is syncronized such that the vacuum timing
belt 260 and the rotating disc 286 rotate on the same cycle. The
;20 sign~cance of this arrangement is described in detail below.
The operation of the feeding mechanism 240 can be best
understood from the foregoing description and by reference to the
drawing. Briefly, the feeding mechanism 240 indexes a number of
fiats 30 down the feeding line 242, where the flats are individually
grabbed by a grasping mechanism 244 and placed on the lower
conveyor 60 of the path 12. The grasping mechanism 244 uses the
vacuum cups 246 to selectively take hold of the flats 30 and move the
flats from the feeding line 240 to the path 12 where they are released
between cleats 66 on the lower conveyor 60.
The operation of the feeding line 242 can best be
understood with reference to Fig. 11. The feeding line 242 is fed a
number of flats 30 by hand or machine onto the slipping surface
248. Preferably, the slipping surface 248 is substantially horizontal
and the primary planar surfaces 31, 32 of the flat letters 30 are
substantiallyvertical. It is preferred that the destination code 33
WO 95132138 ~ ~ ~ PGTlUS95I06911
12
faces to the left in the diagram and the outer edges 37, 38 are kept
even. Guides (not shown) may be used to keep the edges 37, 38 of
the flats 30 even.
As can best be understood with reference to Fig. 11, the
spring 252 and pusher carriage 250 put adequate pressure on the
flats 30 such that the flats are indexed against the retaining idler
roller 254 as each flat 30 is removed, but the pressure of the
carriage 250 is preferably not too much that the flat to be removed
will not slide against the adjacent flat, or the retaining idler roller
cannot spin when the flat is pulled from the feeding line 242.
Preferably, the slipping surface 248 ends and the chute 249 begins
such that only one flat 30a extends over the edge of the chute as the
flats await the next pair of vacuum cups 246. This positioning
allows the passage of only one flat 30 when the flat is grasped and
then moved by the grasping mechanism 242.
Turning now to the operation of the grasping
mechanism 244, the vacuum timing belt 260 is set to rotate clockwise
in Fig. 11 at very high speeds, drawing the vacuum cups 246 from
the feeding line 242 to the sorting line and back around the loop to
repeat the action over again. As discussed earlier, the drive motor
294 for the rotating disc 286 is synchronized with the motor 270 for
the vacuum belt 260, such that the disc 286 and the vacuum timing
belt 260 turn in unison. That is, the disc 286 and vacuum timing belt
260 tum a complete cycle in the same amount of time. In fact, one
ZS motor could replace the two motors 270, 294 and turn each of the
belts 272, 292 by use of a common axle (not shown). By having the
disc 286 and vacuum belt 260 rotate on the same cycle, the disc and
vacuum belt rotate as one unit.
As the disc 286 is rotated, the ports 288 are selectively
positioned against the manifold 283 of the vacuum timing port 284
such that each of the rotating ports intermittently receives suction
from the vacuum system 278 via the constant source of vacuum 280.
When a port 288 is not positioned against the manifold 283, but
instead is against the face of the stationary port 282, the flexible hose
290, and therefore the vacuum cups 246 corresponding with the
~W 0 95132138 PCT/U595/06911
I3
specific rotating port 288, receive no vacuum from the constant
source of vacuum 280.
The intermittent vacuum through the hoses 290 causes
corresponding intermittent suctions through the vacuum cups 246.
By arranging the rotating port and suction system 278 so that suction
first occurs as the vacuum cups 246 reach the feeding line 242, the
first flat 30a, corresponding to the flat which is farthest left on the
feeding line in Fig. 11, is "grasped" by the vacuum going through
the pair of cups 246 engaging the flat. As the vacuum timing belt
260 rotates about its path, the cups 246 maintain their grasp and pull
the flat from the feeding line 242.
The flat 30a grasped by the vacuum cups 246 is carried
to the path 12 and then released at the position of the flat 30b on the
lower conveyor 60. The flat 30b may be released by the vacuum
cups 246 at any point along the path between the feeding line 242
and the lower conveyor 60 so as to allow the flat 30b to fall freely to
the lower conveyor 60, but preferably the flat is placed on the lower
conveyor 60 precisely between two cleats 66.
The vacuum timing port 284 may extend around the
face of the stationary port 282 such that two flats may be grasped at
the same time. In such an arrangement, the second flat 30a is picked
up or grasped before the leading flat 30b is dropped on the lower
conveyor 60.
The unique grasping feature of the grasping mechanism
244 allows flats 30 to be moved fmm the feeding Iine 242 to the path
12 faster and more precisely than gravity working alone. Also, the
grasping feature does not actually require downward movement
from the feeding line 242 to the path 12. Because the flats 30 are
actually grasped, the movement between the two lines could be
sideways or even upward. However, the arrangement set forth in
the drawing is preferred because of the vertical arrangement of the
flats 30.
The grasping mechanism 242 in the present invention
could be replaced by any system which allows firm contact with the
flats 30 and an unmoving engagement between the flats and the
W 0 95132138 ~ ~ PC'T/US95/06911
14
grasper. For example, a frictional engagement with pressure placed
upon the flats could be used. In such an embodiment the flats would
have to be pressed against the side of the chute 249, or some other
surface. Such a system, however, does not offer the advantages of
the present system in that the present system uses vacuum cups which
only require contact with one side of the flats 30. A system utilizing
pressurized engagement with the flats 30 could also damage the flats
when delivering them to the path 12.
Although the preferred embodiment shown in the
drawings is designed for use of flats, it is to be understood that the
general concepts of the apparatus and the method of sorting
described may be used for any type of item which is to be sorted. In
such a .set up, the feeding line 242 could be of any design which
presents an item such that the item may be individually released
from the feeding line and drawn toward or taken to the path I2 by
the grasping mechanism 244.
The automatic feed system 240 can operate at a much
higher speed than prior feeding mechanisms and thereby improves
the productivity of the entire line I0. Designs similar to the one
described have been found to feed flats 30 at the rate of 200
milliseconds-per unit, or five flats per second. At that rate, the
entire automatic sorting system 10 can sort flats 30 at a maximum
rate of 18,000 flats per hour while using only one feeding
mechanism 240.
As discussed in further detail below, after the flat letters
are deposited into the sorting path 12, the letters pass a code scanner
18, and then pass a presence photocell (not shown) immediately
downstream of the data scanner. The letters then pass through a
series of side-by-side ejection modules 24, which, depending on their
mode of operation, can allow letters to pass through to the next
module 24, or to be ejected from the path.
An ejection module 20 for use in the present invention
is pictured in Fig. 6. As can be seen from that drawing, the module
20 includes a pusher 80 having a push rod 82 and a push pad 84. In
W 0 95132138 PGTJUS95I06911
2~s~sss
one embodiment, the push pad 84 extends further out at its base than
its top, the advantage of which will be described below.
The push rod 82 of the ejection module 20 extends into
a high speed electric linear actuator 86. The actuator 86 may
S alternatively be substituted with a solenoid or pressurized air. An
upper linkage 88 and a lower linkage 90 are attached at a central pin
96 at slots 89, 91 to the rod 92 at a location forward of the high
speed electric actuator 86. The upper linkage 88 includes an upper
guide rod 92 which extends a fixed distance from and substantially
10 parallel to the upper conveyor 62 when the ejection module 20 is in
the closed, or "travel", position, such as is shown in Fig. 6.
Likewise, the lower linkage 90 includes a lower guide rod 94 which
extends just above and just to the right of the lower conveyor 60.
The upper and lower linkages 88, 90 are positioned to pivot about a
15 stationary upper pivot point 98, and a stationary lower pivot point
100, respectively. A return spring 102 is preferably attached at one
end to either the upper or lower linkage and attached at the other
end to a fixed position.
The ejection module 20, in one operational mode,
contains flat letters 30 traveling on the path 12 to guide and prevents
falling of the letters. The flat letters 30 travel along the upper and
lower path conveyor belts 64, 69 at a high speed and are kept from
falling over by the guiding effect of the upper and lower rods 92,
94. The arrangement of the upper rod 92 prevents the upper edges
35 of the flat letters 30 from falling too far away from the upper
conveyor belt 69, and the lower rod 94 serves to position the lower
end 36 of the letter in the center of the lower conveyor belt 64.
Thus, the upper linkage 88, along with the guide rod 92, serves as a
jaw which extends over and around the top edge 35 of the flat letters
30 as they travel down the path 12. Likewise, the lower Linkage 90,
along with the lower guide rod 94, serves as a jaw which extends
under and around the flat letters 30 as they travel down the path I2.
This allows the flat letter 30 to be delivered in a substantially upright
position at a high speed, with some degree of "slack" provided
~
W 0 95!32138 ~ ~ PCr/Ils95/06911
i6
between the upper rod 92 and the upper conveyor belt to compensate
for thick or deformed flats.
The ejection module 20 also serves to remove a flat
letter 30 from the path 12 when the flat letter reaches the ejection
module 20 which matches its destination code 33. The feed station
I6 and ejection modules 20 work together with the path 12 so that
flat letters 30 may be sorted at a high speed and a large number of
destinations by automation. Once the flat letters 30 are placed on the
path 12 by the feeding mechanism 40, the letters 30 proceed down
the path 12 and are tracked in accordance with prior art methods.
The scanner 18 reads the destination code 33 on the flat letter 30 and
a programmable logic controller (not shown) selects' a destination, or
certain ejection module 20, for the flat letter 30. A tracking
photocell (not shown), just downstream of the code scanner 18,
identifies the actual presence of the letter and matches this with its
destination and starts the count on a shaft encoder (not shown).
When the shaft encoder registers the correct number of
pulses for the specific destination, a signal is sent to the
programmable logic controller which causes the high speed electric
ZO actuator 86 to activate, forcing the push rod 82 to extend rapidly
outward as the matching flat letter 30 reaches a position immediately
in front of the pusher pad 84. The movement of the push rod 82
forward causes the upper and lower linkages 88, 90 to pivot about
the stationary pivot points 98, 100 and the slots 89, 91 to travel
along the central pin 96 such that the upper and lower linkages are
moved to the position shown in Fig. 7. This arrangement of the
upper and lower linkages 88, 90 moves the upper and lower guide
rods 92, 94 out of the way so that the flat letter 30 may be ejected
from the path of the automatic sorting system 10. Thus, the jaws
open and allow the flat letters 30 to be ejected. Because the push pad
84 extends further outward at its lower end, it ejects the lower edge
36 of the flat letter 30 out further than the upper edge 35 so that the
flat letter lands on the chute 22 and slides into the bin 24 with the
destination code 33 and address label 34 facing upward. Moreover,
the orientation of the push pad 84 relative to the letter 30 causes the
w0 95/32138 PC1'lUS95/06911
~1896~~
m
letter to be ejected upwardly and outwardly so that it will not get
hung up on the Iower conveyor belt 64 as it is ejected from the path
12 into one of the bins.
Once the bins 24 are full, they are ready to be carried to
other sorting machines 10, or directly to a carrier. A letter 30 that
is not sorted for any reason will simply exit the automatic sorting
system 10 at its end and fall into a reject bin (not shown).
An alternative embodiment of an ejection module 120 is
shown in Fig. 9. As can be seen in that figure, the ejection module
120 includes a high speed actuator 186 and push rod 182 which are
similar to the actuator 86 and push rod 82 of the first embodiment.
However, this embodiment includes only one linkage 188 which
pivots from a stationary upper pivot point 198 and is attached to a
return spring 202. This linkage 188 has at one end an upper guide
IS rod 192 and at the other end a pusher pad 184.
As with the fu~st embodiment, the upper guide rod 192
serves to prevent the flat letter 30 from falling too far forward when
tile ejection module 120 is in the travel position. As in the
previously-discussed embodiment, the spaced-apart relative
positioning of the upper guide rod 192 and the upper conveyor 62
allows for some "slack" therebetween to facilitate handling of thick
or deformed flats or packages. To maintain the Iower edge 36 of the
flat letter 30 on the lower conveyor belt 64, the lower conveyor belt
64 in this embodiment includes one beveled side 166 and a sloped
side 168. The beveled side 166 serves to prevent the flat letter 30
from extending too far left in Fig. 9 and the sloped side 168 serves
m hold the flat letter 30 in a central position on the belt 164 until it
is ejected.
As can be seen by Fig. 10, the ejection module 120 is
designed such that when the high speed electric actuator 186 is
activated, the push rod 182 extends outward and the upper guide rod
192 moves out of the way. As this upper guide rod 192 is moving,
the pusher pad 184 contacts the bottom half of the flat letter 30 and
presses it in the direction of the chute 22. Because the pusher pad
184 presses the bottom portion of the flat letter 30 upward and
' W095l32138 ~ ~ PGT/US95/069II
1$
outward as the push rod 182 extends, the flat letter lands on the
chute with the destination code 33 and address Label 34 exposed.
This upward and outward movement also pushes the bottom edge of
the flat letter 30 up and over the sloped surface 168.
It may be understood that one of the distinct advantages
provided by the present invention is that of "positive displacement"
of the flats from the sorting path out of the sorting path by the use of
mechanical plungers. As may be understood, fiats, packages, or any
objects being moved high speed may tend to jam, and a jam of one
letter can quickly become a jam of a multitude of letters. The
present invention, when using a mechanical plunger, provides a
lesser chance of risk by positively displacing the entire letter from
the path with a plunging action, which is believed to be an
improvement over "gated" types of sorters which tend to provide
IS jam points due to the potential of letters becoming pinched when the
gates close.
It should be understood that there are several alternative
sorting configurations which could be used without departing from
the spirit and scope of the present invention. For example, data
scanners could be used on both sides of the sorting path in order to
read data on either side of the path, such as would be the case if the
flats were not fed into the path with data consistently positioned on
one side. In such a situation where the flats are introduced into the
path in more "random" fashion, the ejection modules could, if
desired, be modified to include two plungers or pusher pads, with a
lower pusher pad used to provide the action described above, and a
second, "higher" pad actuated when the data is recognized to be on
the other side of the flat. In such a system, the flats would be fumed
in a manner such that the encoded data would be consistently
oriented (e.g. facing upwardly) regardless of the orientation of the
data when the flats are in the sorting path.
It should also be understood that an air blast could be
used in place of the plungers, although this would not provide the
"positive displacement" feature discussed above.
W09513~138 PCT/US95/06911
~~8g669
19
As can be understood from the foregoing, the sorting
system 10 of the present invention overcomes many problems in the
prior art. The feeding mechanism 40 inputs objects to be sorted in a
systematic order. The ejection module 20 offers not only a
supported guiding system, but also an efficient ejection system which
may be used to sort a large number of packages to a large number of
destinations. Although the automatic sorting system IO described in
the specification is developed to specifically sort flat letters 30, it is
to be understood that the principles of the sorting system 10 could be
employed for any size or shape of items to be sorted.
While the present invention and its various aspects has
been described in detail with regard to preferred. embodiments
thereof, it should be understood that variations, modifications and
enhancements can be made to the disclosed apparatus and procedures
without departing from the spirit and scope of the present invention
as defined in the appended claims.
Y
