U.S. patent number 3,757,939 [Application Number 05/142,600] was granted by the patent office on 1973-09-11 for method and apparatus for sorting articles such as letters.
Invention is credited to Seymour Henig.
United States Patent |
3,757,939 |
Henig |
September 11, 1973 |
METHOD AND APPARATUS FOR SORTING ARTICLES SUCH AS LETTERS
Abstract
System and method for sorting articles, particularly letter
mail, in such fashion that articles having a common characteristic,
e.g., letters with the same address, are delivered as containerized
group containing at least a predetermined threshold number of the
articles. Applied to systems of the type wherein a classifying
apparatus identifies each article and delivers the articles to
individual article retaining stations while retaining cognizance of
the characteristics and locations of the articles, the invention
employs receptacles which are advanced past the retaining stations,
articles having a common characteristic being discharged into the
same receptacle, means being provided whereby any receptacle in
which less than a predetermined number of articles have been
accumulated can be transferred to storage and later retrieved and
advanced again past the article retaining station for addition of
more articles having the same characteristic.
Inventors: |
Henig; Seymour (Kensington,
MD) |
Family
ID: |
22500514 |
Appl.
No.: |
05/142,600 |
Filed: |
May 12, 1971 |
Current U.S.
Class: |
209/584; 209/606;
209/933; 209/559; 209/900 |
Current CPC
Class: |
B07C
3/02 (20130101); B07C 3/006 (20130101); Y10S
209/90 (20130101); Y10S 209/933 (20130101) |
Current International
Class: |
B07C
3/00 (20060101); B07C 3/02 (20060101); B07c
003/02 () |
Field of
Search: |
;209/72,DIG.1,73,74
;214/11 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schacher; Richard A.
Claims
What is claimed is:
1. In a sorting system of the type comprising article classifying
and retaining means and release means for discharging articles from
the classifying and retaining means selectively in accordance with
predetermined characteristics of the articles, the combination
of
main conveying means;
a plurality of articles receiving receptacles adapted to be
conveyed by said main conveying means,
said main conveying means being constructed and arranged to advance
said receptacles past the article classifying and retaining means
when said receptacles are disposed on said main conveying
means;
off-bearing means for receiving said receptacles from said main
conveying means;
receptacle storage means;
first recirculating conveyor means arranged to deliver said
receptacles to said storage means;
selectively actuatable transfer means operative, when actuated, to
transfer a receptacle from said main conveying means to said first
recirculating conveyor means;
control means responsive to the cumulative number of articles
discharged into each of said receptacles, as the receptacles are
advanced past said article classifying and retaining means, for
actuating said transfer means to transfer from said main conveying
means to said first recirculating conveyor means such of said
receptacles as contain a cumulative number of article less than a
predetermined value; and
second recirculating conveyor means for retrieving receptacles from
said storage means and returning the same to said main conveying
means to again receive articles from the classifying and retaining
means.
2. A sorting system according to claim 1 and wherein the
classifying and retaining means is of the type comprising a
plurality of article retaining stations arranged in a generally
horizontal series and each arranged to discharge articles
downwardly,
said main conveying means extending horizontally below the article
retaining stations and lengthwise of the series thereof in such
fashion that each of said receptacles advanced by said main
conveying means will pass successively beneath the article
retaining stations,
the combination further including
means for correlating each of said receptacles supplied to said
main conveying means with a particular predetermined characteristic
of articles present in the retaining stations; and
release control means for controlling operation of the release
means for discharging articles from the retaining stations in such
fashion that the articles having said particular predetermined
characteristic are delivered into the correlated receptacle by
successive release from the respective retaining stations as the
correlated receptacle is advanced along the series of retaining
stations by said main conveying means.
3. A sorting system according to claim 2 and wherein the retaining
stations are of a type adapted to retain relatively thin flat
articles such as letters,
said receptacles have a length which is large as compared to the
thickness of the flat articles and are adapted to be advanced
lengthwise by said main conveying means, and
said release control means is operative to cause discharge of the
flat articles from the retaining stations in a timed succession
such that the first flat article discharged drops to a location
adjacent the trailing end of the advancing receptacle and each
successive discharged article drops to a location immediately ahead
of the preceding discharged article.
4. A sorting system according to claim 3 wherein
each of said receptacles is provided with a longitudinally
extending series of upwardly opening locator notches each
dimensioned to receive and retain the bottom edge of one of the
flat articles.
5. A sorting system according to claim 2 and further comprising
means for retaining a supply of said receptacles and delivering the
same individually to said main conveying means.
6. A sorting system according to claim 1 and further comprising
means adjacent said off-bearing means and operatively arranged to
apply covers to said receptacles.
7. A sorting system according to claim 1, wherein
said storage means comprises a plurality of horizontal storage
conveyors arranged in a spaced group with the input ends of all of
said storage conveyors disposed at one side of the group and the
delivery ends of said storage conveyors disposed at the other side
of the group;
said first recirculating conveyor means includes a conveyor
extending past the input ends of said storage conveyors; and
said second recirculating conveyor means includes a conveyor which
extends past the delivery ends of said storage conveyors.
8. A sorting system according to claim 7 and further comprising
a plurality of receptacle transfer devices each located adjacent
the input end of a different one of said storage conveyors and
cooperating with said first recirculating conveyor means for
selective delivery of receptacles to the respective storage
conveyor.
9. A sorting system according to claim 7, and further
comprising
a plurality of receptacle stop devices each operatively arranged
adjacent the delivery end of a different one of said storage
conveyors and actuatable between an operative position, in which
the stop device will engage and hold stationary a receptacle
advanced thereto by the storage conveyor, and a retracted position,
in which the stop device allows receptacles to be delivered by the
storage conveyor.
10. A sorting system according to claim 7 and further
comprising
a by-pass conveyor having an input end and a delivery end and
arranged with its input end adjacent said second recirculating
conveyor means at a point downstream from said storage conveyors
and its delivery end adjacent said first recirculating conveyor
means at a point upstream from said storage conveyor means; and
selectively actuatable transfer means adjacent the input end of
said by-pass conveyor for transferring receptacles from said second
recirculating conveyor means to said by-pass conveyor.
11. A sorting system according to claim 10 and further
comprising
a stop device disposed at the delivery end of said by-pass conveyor
and actuatable between an operative position, in which the stop
device will engage and hold stationary a receptacle advanced
thereto by said by-pass conveyor, and a retracted position, in
which the stop device allows receptacles to be delivered by said
by-pass conveyor to said first recirculating conveyor means.
12. In a sorting system for thin flat articles such as letter, the
combination of
classifying and retaining means comprising
means for receiving the articles and determining a characteristic
thereof,
a plurality of article retaining stations arranged in a series and
each adapted to retain one of the articles and operable to release
the retained article,
means for delivering articles from said first-mentioned means each
to a different one of said retaining stations;
conveying means arranged to carry a plurality of article receiving
receptacles past said series of retaining stations;
computer operated control means operative to release from said
retaining stations articles having a selected characteristic, with
such release effected in timed relation with the movement of a
receptacle on said conveying means such that the released articles
having the selected characteristic are deposited in the
receptacle,
said control means including means for determining whether the
total of articles released for deposit in the receptacle reaches a
predetermined threshhold value;
receptacle storage means;
receptacle diverting means cooperating with said conveying means in
a location to be reached by the receptacles after the receptacles
have been carried past said retaining stations,
said diverting means being actuatable between a first position, in
which receptacles are allowed to pass said diverting means, and a
second position,
said control means being operative to actuate said diverting means
to said second position, to divert a receptacle to said storage
means, only when the receptacle contains a number of articles less
than the predetermined threshhold value when the receptacle reaches
said diverting means; and
means operated by said control means for recalling from said
storage means and delivering to said conveying means a receptacle
containing articles of a particular characteristic when additional
articles having that characteristic have been accumulated in said
series of retaining stations.
13. In an article sorting system adapted to deposit groups of like
articles in receptacles, the combination of
conveying means for conveying the receptacles to a discharge point
after articles having been deposited therein;
receptacle diverting means operatively arranged relative to said
conveying means and actuatable to divert therefrom receptacles
which contain a number of articles which is less than a threshhold
value;
receptacle storage means;
first recirculating conveyor means arranged to deliver receptacles
from said diverting means to said storage means; and
second recirculating conveyor means arranged to deliver receptacles
from said storage means to said conveying means.
14. An article sorting apparatus according to claim 13, wherein
said storage means comprises
a plurality of continuously driven endless storage conveyors each
of an effective length adequate to accommodate a plurality of the
receptacles to be stored and each having an input end and a
delivery end,
said storage conveyors being arranged in a spaced series with the
input ends of the storage conveyors all disposed at one side of the
series and the delivery ends of the storage conveyors all disposed
at the other side of the series; and
a plurality of stop devices each disposed adjacent the delivery end
of a different one of said storage conveyors and operative
selectively to engage and stop a receptacle advanced thereto by the
storage conveyor and to release the conveyor for delivery by the
storage conveyor.
15. An article sorting apparatus according to claim 14, wherein
each of said storage conveyors comprises two parallel endless belts
extending side by side but spaced apart, and
said stop devices are each located between said belts of the
respective one of said storage conveyor.
16. In the sorting of letters by first depositing the letters
individually in upright retaining stations arranged in a horizontal
series and then releasing letters of a selected category from the
retaining stations in progression along the series and in timed
relation with movement of a conveyor arranged below the retaining
stations, the improvement comprising
advancing along the conveyor an open top receptacle,
the bottom of said receptacle having a series of upwardly opening
locating and retaining notches,
the receptacle having an end wall which trails as the receptacle is
moved along the conveyor and which slants upwardly and rearwardly;
and
dropping the letters toward the bottom of the receptacle in such
fashion that each letter is substantially vertical as it drops and
the lower edge thereof engages in one of the notches presented by
the bottom wall of the receptacle,
the first letter dropped engaging in a notch adjacent the trailing
end wall of the receptacle and continued advance of the receptacle
then causing that letter to pivot into engagement with the trailing
end wall,
the other letters being similarly dropped to engage in successive
ones of the locating and retaining notches and continued advance of
the receptacle causing each letter to pivot into engagement with
the next preceeding letter.
17. The method for providing a group of flat, relatively thin
articles such as letters, comprising
providing a plurality of the articles in a plurality of upright
retaining stations with each article disposed in a different one of
the stations,
the stations being arranged in a series which extends at least
generally horizontally;
advancing an open top receptacle beneath the retaining stations
with the receptacle travelling lengthwise of the series at a
predetermined constant rate,
the receptacle having a bottom provided with a plurality of
upwardly opening article positioning notches,
the trailing end of the receptacle presenting an upwardly and
rearwardly inclined article supporting surface,
the first one of the article positioning notches being located
immediately in advance of the bottom edge of the upwardly and
rearwardly inclined article supporting surface and the remaining
notches being present as a series progressing toward the leading
end of the receptacle and in which the effective spacing of the
notches approximates the maximum thickness of the articles;
dropping a first article from one of the retaining stations when
the receptacle has advanced to a position such that the first
article will drop to a position in which the lower edge thereof is
engaged in the first notch of the series of notches,
continued advance of the receptacle causing the first article to
tilt rearwardly until it is engaged with and supported by the
upwardly and rearwardly inclined article supporting surface;
and
successively dropping additional articles from their respective
retaining stations in such timed relation to the advance of the
receptacle that each article is dropped to a position in which the
lower edge thereof is engaged in one of the article positioning
notches just in advance of the preceding article,
advance of the receptacle causing each successive article, when so
dropped and engaged in one of the notches, to tilt rearwardly and
come to rest in an upwardly and rearwardly inclined position in
which the same is supported by the immediately preceding
article.
18. The method for sorting articles into groups of articles having
the same characteristic, comprising
depositing the articles in a plurality of article retaining
stations arranged in a series;
maintaining an inventory of the articles so deposited in the
retaining stations so that the number of articles of any given
characteristic present in the series is known;
successively passing a plurality of receptacles along the series of
retaining stations;
releasing articles of each characteristic from the successive
retaining stations of the series into a different predetermined one
of the receptacles as that receptacle is passed along the
series;
maintaining a count of the articles released into each
receptacle;
removing for further handling those of the receptacles in which the
number of articles is at least equal to a predetermined threshhold
value;
diverting to storage those of the receptacles in which the number
of articles is less than the threshhold value,
the step of depositing articles in the retaining stations
continuing over a period which is long in comparison to the time
required to pass a receptacle along the series of retaining
stations;
recalling the stored receptacles from storage when additional
articles having the characteristics of the articles already present
in the respective stored receptacles have been deposited in the
series of retaining stations; and
passing the recalled receptacles again along said series of
retaining stations to again receive articles therefrom having the
respective characteristics of the articles already present in the
receptacles.
19. The method according to claim 18, wherein
the articles to be sorted are letters and the characteristics are
address categories;
the letters are deposited in the retaining stations in upright
position with the addressed sides of the letters all facing in the
same direction throughout the series;
the receptacles are each provided with a plurality of locator
notches arranged in a series; and
the letters are each released from the stations into engagement
with one of the locator notches of the respective receptacle and
are retained in the receptacle with the addressed sides of the
letters all facing in the same direction.
20. The method according to claim 19, wherein
the series of retaining stations extends horizontally;
the receptacles are open top receptacles and are passed along a
horizontal path immediately below and aligned with the series of
retaining stations; and
the letters are dropped from the retaining stations into the
respective receptacles.
Description
This invention relates to sorting of articles, particularly flat
relatively thin articles such as letters. The invention provides a
method and apparatus whereby such articles can be sorted into
groups of articles having a common characteristic, e.g., the
geographic destination of a letter, in a greatly improved
manner.
It is generally recognized that a number of factors, such as the
expanding population and the economic requirement for increased
man-hour productivity, necessitate mechanization of the handling of
letter mail. Though a similar requirement applies to other
articles, such as orders, bills, and like documents in certain
business operations, mechanization of the handling of letters
appears to be the most critical present need, and the invention
will acordingly be described with particular reference to that
application. Prior-art workers have done much work in connection
with mechanized letter handling systems and have proposed apparatus
which promises to be satisfactory for some of the operations
involved. In particular, code controlled letter sorters of various
types have been provided which are capable of accepting an input
of, e.g., 10 letters per second, "reading" the envelope of each
incoming letter and, in various ways, classifying the letters as to
their distinctions. Automated letter sorters presently in
development are expected to handle letters at much higher ratio
e.g., 100 letters per second. For complete systems employing such
sorters to be successful, however, there must also be provided a
rapid and dependable way to acquire the respective groups of
letters from the sorter and to deliver such groups either for
further processing or for dispatch to the common destination
distinguishing the group. This current requirement has been
characterized, for example, as calling for a system which will
deliver the letters in "bundles" of letters 3-6 in. high, so that
letter sorters presently being developed will require a system
delivering an average 75-letter "bundle" every 0.5-1 second. Stated
that simply, the problem of handling the output of the present code
controlled letter sorters can be satisfied, for example, by systems
of the type disclosed in U.S. Pat. No. 3,300,066, issued Jan. 24,
1967, to Seymour Henig and Ervin S. Palasky.
The problem is complicated, however, by the fact that, in presently
practical operation of code controlled letter sorters, the number
of sorted letters to be found for any one destination at any given
time is, e.g., about one-half that number which makes up the
average "bundle." Hence, a system designed simply to accept the
groups of letters, "bundle" the groups and deliver "bundles" equal
to the output of the code controlled letter sorter necessarily
fails, either to provide "bundles" of the specified size, on the
one hand, or to provide the desire rate of output, on the other
hand. Further, the concept of handling free groups of letters and
"bundling" each group involves a number of inherent disadvantages.
One of these is that a simple group of letters cannot be diverted
easily to a processing step other than "bundling. " Another is that
"bundled" letters become bent or otherwise distorted so as to be
unsuitable for further machine processing.
It is accordingly a general object of the invention to provide an
apparatus and method which can accept the output of a high speed
article sorter and deliver the articles not only at the desired
speed but also in groups of the desired number.
Another object is to devise such a method and apparatus capable of
delivering groups of articles with the number of articles in each
group being uniform, regardless of the average number of articles
characteristic of the group otherwise present in a population of
unsorted articles at any given time.
A further object is to provide an improved letter sorting and
handling apparatus and method capable of delivering the letters in
the same condition in which they are supplied.
Broadly stated, the invention is based upon the concept of
delivering articles, such as letters, from a sorting apparatus into
independently handleable receptacles rather than, e.g., onto a
conveyor belt or the like. With articles having a common
characteristic delivered to a receptacle, that receptacle can then
be recirculated in the event that the number of articles then
present in the receptacle is less than the predetermined threshold
value required for ultimate delivery.
In order that the manner in which the foregoing and other objects
are attained according to the invention can be understood in
detail, particularly advantageous embodiments thereof will be
described with reference to the accompanying drawings, which form a
part of the original disclosure of this application, and
wherein:
FIG. 1 is a diagram illustrating one manner in which the method of
the invention can be practiced;
FIG. 2 is a semi-diagrammatic illustration of an apparatus
according to one embodiment of the invention;
FIG. 3 is a perspective view of a receptacle employed with the
apparatus of FIG. 2;
FIGS. 4 and 5 are fragmentary sectional views taken on lines 4--4
and 5--5, respectively, FIG. 3;
FIGS. 6 and 6A are diagrammatic views illustrating the manner in
which the receptacle of FIGS. 3-5 is employed with the apparatus of
FIG. 2;
FIG. 7 is a perspective view of the receptacle of FIGS. 3-5 with a
second identical container applied thereto to provide a closed
container;
FIG. 8 is a front elevational view of a receptacle supply device
employed in the apparatus of FIG. 2;
FIG. 9 is a top plan view of a receptacle transfer fork forming
part of the apparatus of FIG. 2;
FIG. 10 is a top plan view of a transfer pusher and associated
conveyor mechanism forming part of the apparatus of FIG. 2;
FIG. 11 is a vertical sectional view of a receptacle restraining
and releasing mechanism employed in the apparatus of FIG. 1;
FIG. 12 is a vertical sectional view taken on line 12--12, FIG. 11;
and
FIG. 13 is a schematic diagram of the computer operated control
system employed in the apparatus of FIG. 2.
GENERAL DESCRIPTION OF THE METHOD
Referring to FIG. 1, the method is generally illustrated for
sorting flat articles, hereafter referred to as letters into groups
of articles of the same category and delivering such groups only
when the number of articles collected at least equals a selected
threshold value. The letters are fed successively at high speed to
a conventional automated device 1, typically an optical character
reader, which identifies each letter, e.g., as to its address
category, and transmits that identification for storage in the form
of a digital electronic signal. Each letter is delivered from
device 1 to a device 2 in which the letter is stored in an upright
retaining station, an appropriate signal being developed and stored
to indicate that the respective retaining station contains a letter
of the particular category. Open top receptacles 3 are delivered
successively from a receptacle storage device 4 onto a horizontal
conveyor 5, each receptacle 3 so delivered being identified to
receive letters of one particular category. The identification of
receptacle 3 is also transmitted for storage as a digital
electronic signal.
The retaining stations of device 2 are arranged in a horizontally
extending series and the conveyor 5 is positioned to advance
receptacles 3 along a horizontal path aligned below the series of
retaining stations. Thus, each receptacle 3 is passed beneath all
of the retaining stations in succession. Whenever a receptacle 3 is
deposited on conveyor 5, the selected category for the receptacle
is recorded at the end of a synchronous progression of such
receptacle category codes, in the general fashion disclosed in
aforementioned patent 3,300,066, so that the progress of the
particular receptacle along the series of retaining stations is
known. When a reference point on the receptacle reaches a
predetermined point relative to the first retaining station
containing a letter of the category to be collected in the
receptacle, device 2 is operated to drop that particular letter,
the letter accordingly coming to rest in a particular position in
the receptacle. This operation is repeated for successive
additional letters of that category until either the maximum
allowable number of letters has been collected in the receptacle or
the receptacle reaches the end of the series of retaining stations.
As later described in detail, the successive letters are so
deposited in the receptacle, and the receptacle is so constructed,
that collected letters will be retained in a consistent orientation
with all address surfaces facing in the same direction. If the
number of letters collected in the receptacle by the time the end
of the series is reached exceeds the threshhold value, the
receptacle is then passed through a diverting station 6, without
being diverted, and is delivered to suitable off bearing conveyor
means. If, on the other hand, a number of letters less than the
threshhold value has been collected when the receptacle reaches the
end of the series of retaining stations, the receptacle is then
diverted at station 6 and delivered to a storage means 7, the
identity, content and position of the receptacle being retained in
the form of stored digital information.
When device 2 again contains a sufficient quantity of letters of
that particular category, the stored receptacle is automatically
retrieved and delivered again to conveyor 5 so as to be advanced
again along the series of retaining stations. During such advance
of the receptacle along the series of retaining stations,
additional letters of the same category are delivered, either until
the number of letters collected in the receptacle reaches the
threshold value or until, all of the letters of that category
present in device 2 having been collected, the receptacle passes
again to station 6 to be delivered to the off bearing means or
again diverted to storage, as the case may be.
TYPICAL APPARATUS EMBODIMENT
FIG. 2 illustrates a typical apparatus embodiment of the invention
comprising the components 2-7 hereinbefore described, the
conventional optical character reader or the like indicated at 1 in
FIG. 1 being omitted for simplicity. Device 2 can be of the type
disclosed in U.S. Pat. No. 3,300,066 and includes a horizontally
extending series of letter retaining stations 10. Each station 10,
as seen in greater detail in FIGS. 6 and 6A, is in the form of an
upright slot-like compartment, open at the top for insertion of
letters and closed at the bottom by a pivoted door 11. Device 2
further comprises a plurality of compartmental traverse cars 12
supported for movement in the manner indicated by the arrows in
FIG. 2, cars 12 being operated to receive the individually
identified letters from the device 1, FIG. 1,and deliver the
letters selectively to the retaining stations 10. During operation
of device 2, data in the form of digital electronic signals is
developed and stored in a control computer, later described with
reference to FIG. 13, to correlate letter category and retaining
station position information in the manner disclosed in U.S. Pat.
No. 3,300,066.
LETTER COLLECTING RECEPTACLES
Receptacles 3 are identical, each comprising a bottom wall 15, an
upwardly and rearwardly inclined trailing end wall 16, an upright
front end wall 17, and upright side walls 18 and 19. The receptacle
is advantageously molded as an integral piece from a suitable
polymeric material. Bottom wall 15 is of transversely corrugated
configuration, presenting a plurality of straight, elongated,
upwardly opening notches 20 which extend transversely of the
receptacle so as to be parallel to end walls 16 and 17. As best
seen in FIGS. 6 and 6A, each notch 20 is of triangular
cross-section, being defined by a flat rear surface and a flat
front surface, with the rear surface slanting upwardly and
rearwardly at a larger angle (relative to the vertical plane
passing through the bottom of the notch) and the front surface
slanting upwardly and forwardly at a smaller angle. Bottom wall 15
is continuous, notches 20 extending from side wall 18 to side wall
19.
Notches 20 are identical and can be considered as arranged
side-by-side in a series which progresses from end wall 16 to end
wall 17, with the first notch 20' of the series extending along the
bottom edge of the trailing end wall 16 in such fashion that the
front face of end wall 16 constitutes an extension of the rear
surface of notch 20'. The mouth width of the notches, i.e., the
space between adjacent pairs of ridges presented by the notches,
and thus the effective spacing of the notches, approximates the
maximum thickness of the letters to be collected.
Rear end wall 16 has a slant height which approximates three
quarters of the maximum width of the letters to be collected in the
receptacle. Front end wall 17 extends upwardly at right angles to
the plane of bottom wall 15 for a distance approximately one-third
the projected height of wall 16 and terminates in a straight upper
edge. Side wall 18 includes a flat lower portion 21 and a flat
upper portion 22, the two portions 21, 22 lying in vertical planes
with the plane of portion 22 displaced upwardly from that of
portion 21 and the two portions being integrally joined in such
fashion that the lower edge of portion 22 is defined by a
downwardly facing outer shoulder 23. Similarly, side wall 19
includes lower portion 24, upper portion 25, and a downwardly
facing shoulder 26 along the lower edge of portion 25. The
transverse dimensions of the receptacle are such that the space
between the opposing faces of portions 22 and 25 is very slightly
greater than the distance between the outer face of portion 21 and
the outer face of portion 24. At the front end of the receptacle,
the front edges 27, 28 of upper portions 22 and 25, respectively,
slant upwardly and rearwardly at the same angle of inclination as
rear end wall 16, edges 27, 28 being straight and commencing at the
upper edge of front wall 17.
The upper edges of side wall portions 22 and 25 are straight and
parallel to the bottom wall. The upper edge of portion 22 includes
a front half 29, FIGS. 3 and 5, in the form of a straight elongated
bead of circular transverse cross-section such that the edge
portion 29 presents a right cylindrical surface extending for
substantially more than 180.degree., that surface joining inclined
shoulders 30, FIG. 5. The upper edge of portion 22 also includes a
rear half 31 in the nature of a groove having a curved transverse
cross section which extends for more than 180.degree. and has a
radium of curvature substantially equal to that of the bead
constituted by upper edge portion 29. The upper edge of upper
portion 25 of side wall 19 is identical with that of portion 22 of
side wall 18 and includes a front half in the form of a bead 32 and
a rear half in the form of a groove 33.
RECEPTACLE CONVEYING MEANS
The main receptacle conveying means 5 can, as shown FIG. 2, include
a first endless belt conveyor 40 arranged to receive receptacles 3
from storage device 4 and deliver the receptacles successively to a
short, driven roller conveyor 41. Conveyor 41 delivers the
receptacles to a horizontal endless belt conveyor 42 extending
below the horizontally extending series of letter retaining
stations 10 of device 2. Conveyor 42 in turn delivers to a short
endless belt conveyor 43 located at station 6, and that conveyor in
turn is arranged to deliver to an off-bearing conveyor 44.
Cooperating with main conveying means 5 are a first recirculating
conveyor 45 which extends vertically in a location beside the path
of travel of the receptacles at station 6, and a second
recirculating conveyor 46 which extends vertically beside roller
conveyor 41. Conveyor 45 is an endless ladder conveyor including
receptacle supporting fingers 47, FIGS. 2 and 10, carried by
endless belts 48, the arrangement being such that the conveyor
operates as an elevating conveyor to deliver diverted receptacles
from station 6 to appropriate input points of storage means 7.
Conveyor 46 can be identical with conveyor 45, so as to include
receptacle supporting fingers 49 carried by endless belts 50, but
is operated to lower receptacles from the discharge points of
storage means 7 to either a by-pass conveyor 51 or the roller
conveyor 41.
A receptacle transfer device 52, FIGS. 2 and 9, is provided at
diverting station 6 and comprises a parallelogram linkage including
arms 53 and a cross-link 54, arms 53 being of equal length and
pivoted at one end respectively to stationary supports 55, and link
54 having its ends pivoted respectively to points on arms 53
equally spaced from the respective supports 55. A fork 56, best
seen in FIG. 9, is carried by the free ends of arms 53 and
comprises two parallel fingers 57 each journalled in the free end
portion of a different one of the arms 53. Fingers 57 can be
cylindrical rods and include short end portions 58 which project
from one side of the respective arms 53 and are rigidly
interconnected by an arm 59. Long portions 60 of fingers 57 project
from the opposite side of the respective arms.
The pivoted axes provided for arms 53 at supports 55 are horizontal
and parallel. Arms 53 lie in a vertical plane which is parallel to
and located immediately adjacent one side of the aligned assembly
of conveyors 5, 43 and 44. The spacing between fingers 47 and the
location of device 51 relative to the conveyors are such that, when
arms 53 are swung about their pivotal axes, the arcuate path of
travel of fingers 57 determined by the parallelogram linkage is
such that one finger 57 passes freely through the space between the
delivery end of conveyor 5 and the input end of conveyor 43, and
the other finger 57 passes freely through the space between two of
the rollers of the conveyor 43. The space between fingers 57 is
less than the length of the bottom wall 15 of receptacle 3. The
parallelogram linkage has a normal position (seen in solid lines in
FIG. 2) in which the fingers 57 are disposed below the path of
travel of the receptacles 3 along conveyors 5 and 43, so that, when
the linkage is in its normal position, receptacles 3 can pass along
the series of conveyors and exit via conveyor 44. The parallelogram
linkage is movable to an actuated position, shown in broken lines
in FIG. 2, in which fork 56 is considerably above conveyors 43, 44
and immediately in front of ladder conveyor 45. The linkage is also
movable to return the fork to its normal position. To accomplish
such operation, a suitable conventional electrically operated
reversible drive motor (not shown) is operatively connected to the
parallelogram linkage.
Each pair of supporting fingers 47 of conveyor 45 are spaced apart
by a distance effectively smaller than the spacing between fingers
57 of fork 56. Operation of the parallelogram linkage is so
controlled that movement of the linkage to bring fork 56 to its
actuated position terminates with the fingers 57 of the fork
disposed between the paths of upward travel of fingers 47 of
conveyor 45. Accordingly, device 52 can be operated to pick up a
receptacle 3 from conveyor 43, when that receptacle has been
identified as containing a number of letters less than the
threshold value, transfer the receptacle 3 to the actuated position
shown in broken lines in FIG. 2, and hold the receptacle there
until a pair of fingers 47 of conveyor 45 is engaged beneath the
receptacle, the receptacle then being carried upwardly by conveyor
45, and the parallelogram linkage then being operated to return
fork 56 to its normal position.
Storage means 7 comprises a plurality of endless horizontal storage
conveyors 65, FIG. 2, each comprising two relatively narrow endless
belts 66 which are parallel and spaced apart, as seen in FIGS. 11
and 12. Conveyors 65 are arranged in a vertical series and are of
equal length such that the input end of each conveyor 65 is
adjacent conveyor 45 and the delivery end of each conveyor 65 is
adjacent conveyor 46. Bypass conveyor 51, FIG. 2, identical with
storage conveyors 65 but arranged with its input end adjacent
conveyor 46 and its delivery end adjacent conveyor 45, is provided
below the lowermost storage conveyor 65. The arrangement of
recirculating conveyors 45, 46, storage conveyors 65 and bypass
conveyor 51 is such that any receptacle 3 diverted onto conveyor 45
can be delivered to any one of the storage conveyors 65 and, when
desired, recovered from that storage conveyor, transferred to
conveyor 46 and delivered by conveyor 46 to conveyor 5 to again be
passed beneath the letter retaining stations 10.
To transfer receptacles 3 from conveyor 45 to storage conveyors 65,
a plurality of transfer devices 70, FIG. 10, are employed, there
being one device 70 for each conveyor 65. Transfer device 70
comprises an endless belt 70 carried by two horizontally spaced
rollers 72 arranged in turn about vertical axes and so positioned
that the straight runs of belt 71 are parallel to and spaced
forwardly from the front of conveyor 45, the distance between
conveyor 45 and device 70 being adequate to allow the fingers 47 of
conveyor 45, and any receptacle 3 carried thereby, to pass between
conveyor 45 and transfer device 70. Two pusher bars 73 are secured
to belt 71 in such fashion as to project horizontally outwardly
therefrom, the pusher bars 73 being at right angles to the straight
runs of belt 71 when occupying positions along the straight runs.
Pusher bars 73 are of a length such that their tips pass near, but
do not engage, the adjacent straight runs of belts 48 of conveyor
45 when device 70 is operated. Thus, during the appropriate half of
each complete cycle of movement of belt 71 in its closed path, one
of the bars 73 will be caused to sweep horizontally completely
across the space between transfer device 70 and conveyor 45.
The input ends of storage conveyors 65 are spaced from the vertical
path of travel of the nearer ones of fingers 47 of conveyor 45 by a
distance significantly less than the length of bottom wall 15 of
receptacle 3. The nearer one of rollers 72 of transfer device 70 is
adjacent the input end of the corresponding one of the storage
conveyors 65. Accordingly, when a receptacle 3 is supported by one
set of fingers 47 of conveyor 45 and conveyor 45 is stopped with
that set of fingers aligned horizontally with the upper run of the
respective storage conveyor 65, one half cycle of operation of the
transfer device 70 for that storage conveyor will cause one of the
pusher bars 73 to come into flush engagement with front wall 17 of
the receptacle and will result in the receptacle 3 being pushed
horizontally off of the fingers 47 and onto the storage conveyor
65.
To accomplish such operation, a continuously operating rotary
electric motor (not shown) is operatively connected to one of the
rollers 72 via an electromagnetically operated clutch-and-brake
device so that the clutch can be controlled to cause the device 70
to operate for one half cycle on demand. Conveyors 45 and 46 can be
driven in the same fashion, with the clutches operated to
disconnect the drive motors, so stopping the conveyors, on
demand.
One of the transfer devices 70 is also located adjacent conveyor 46
at the input end of bypass conveyor 51 and is operated, in the same
manner just described, to transfer receptacles 3 from conveyor 46
to the bypass conveyor when required.
Storage conveyors 65 are of a length adequate to accommodate a
plurality of the receptacles. For each storage conveyor, belts 66
are driven continuously, in a direction to carry the receptacles
from conveyor 45 toward conveyor 46, and a receptacle stop device
75, shown in detail in FIGS. 11 and 12, is provided adjacent the
delivery end of the storage conveyor to stop the first receptacle 3
to arrive, other receptacles 3 then accumulating behind the stopped
receptacle. Each stop device 75 comprises a horizontal frame plate
76 which underlies the upper run of belts 66 of the storage
conveyor and is provided with a rectangular central opening 77
slidably accommodating a stop member 78. Member 78 is an integral
block having a top face provided with spaced ridges 79, FIG. 11,
which extend transversely of belts 66 and are of cross-sectional
shape and size to engage in the complementary downwardly opening
notches 20b presented by the bottom wall 15 of each receptacle 3.
Member 78 has two flat dependent flanges 80 which are parallel with
the line of travel of conveyor 65 and spaced apart transversely
thereof, each flange 80 being provided with a downwardly opening
vertical slot 81. Between flanges 80, member 78 has a flat bottom
face 82 lying in a horizontal plane.
Member 78 is supported vertically by an eccentric roller cam 83
fixed to a horizontal shaft 84 which extends through slots 81, the
surface of cam 83 being engaged with bottom face 82. At one end,
shaft 84 is connected to and supported by an electromagnetically
operated half-revolution clutch 85 driven by a continuously
operating rotary electric motor 86 secured to plate 76. At its
other end, shaft 84 is journalled in a bracket 87 secured to and
depending from plate 76.
Cam 83 is so dimensioned and oriented that one half-revolution of
shaft 83 will cause the cam to raise member 78 to interpose ridges
79 in the path of travel of the bottom wall 15 of any receptacle
carried to the device 75 by the conveyor 65, and the next
half-revolution of shaft 84 will cause the cam to allow member 78
to fall by gravity until ridges 79 are below belts 66 of the
conveyor and thus out of the path of travel of the bottom wall of
the receptacle. When member 78 has been raised by cam 83, a
receptacle 3 being advanced by conveyor 65 will ratchet over ridges
79 until those ridges engage in notches 20b and the receptacle is
stopped. When member 78 is lowered by the next half-revolution of
the cam, the receptacle is immediately released and carried forward
by conveyor 65, travelling off the delivery end of that conveyor
and onto a set of the supporting fingers 49 of conveyor 46.
Conveyors 40-44 are driven continuously at the same feed rate.
Conveyors 45 and 46 are driven incrementally, so that the
respective pairs of fingers 47 of conveyor 45 and the respective
pairs of fingers 49 of conveyor 46 stop in alignment with the upper
runs of storage conveyors 65 at the end of each increment of travel
of conveyors 45,46.
EMPTY RECEPTACLE SUPPLY
Since the distance between the outer faces of lower side wall
portions 21 and 24 is slightly less than the distance between the
inner faces of the upper side wall portions 22 and 25, a plurality
of the receptacles 3 can be arranged as a nested stack in the
manner seen in FIG. 8. With the receptacles thus arranged,
retaining dogs 90 of stack support 91 can be engaged respectively
beneath shoulders 23 and 26 of the lowermost receptacle 3 to
support the stack of receptacles. A second set of retaining dogs 92
is provided which can be brought into and out of engagement beneath
the shoulders 23 and 26, respectively, of the next higher
receptacle 3 in the stack. Accordingly, with dogs 92 engaged, dogs
90 can be actuated to release the lowermost receptacle, and the
dogs 92 can then be disengaged to allow the stack to descend until
the dogs 90, having been returned to their original positions,
engage and support the newly arrived receptacle 3. The dogs 90, 92
can be operated by a suitable electromagnetic actuator (not shown)
to drop the receptacles 3 one at a time onto conveyor 40, with the
time of deposit of each receptacle accurately determined. Conveyor
40 is continuously driven to deliver the receptacles successively
onto roller conveyor 41 which, in turn, delivers them to main
conveyor 42.
ANCILLARY EQUIPMENT
Receptacles 3 containing at least the threshhold number of letters
at the time they reach the end of conveyor 42 are passed through
station 6 by conveyor 43 and delivered onto conveyor 44. Any
additional operations required can be accomplished while the
receptacles are on conveyor 44, or conveyor 44 can be employed
simply as an off-bearing conveyor. Typically, a device 95 is
positioned above conveyor 44 to print and apply to each receptacle
3 a label indicating, e.g., destination for the receptacle. And a
device 96 is provided to apply to each receptacle 3 an identical
but inverted receptacle, as a cover, to form the completely closed
container shown in FIG. 7.
COMPUTER OPERATED CONTROL SYSTEM AND ITS FUNCTION IN CARRYING OUT
THE METHOD
FIG. 13 illustrates a control system employed to accomplish
operation of the various components of the apparatus of FIG. 2 in
proper sequence and timed relation to carry out the method. The
control system comprises a conventional general purpose electronic
digital computer, indicated generally at 100 and comprising tape
and core data storage and peripheral interface units to cooperate
with the electromechanical actuators employed in the apparatus, as
well as with the optical character reader and an input-output
multiplexer. Data is supplied in the form of digital signals to the
computer, via interface unit 101, with respect to, e.g., letter
destination address as determined by the optical reader 1, and the
location of the particular letters in the retaining stations 10,
this being accomplished generally in accordance with my U.S. Pat.
No. 3,512,949, issued Apr. 4, 1967, and in such fashion that the
computer 100 maintains a running inventory of the letters of
various address categories stored in the retaining stations 10,
with the inventory including data representing the location of each
retaining station 10 which contains a letter of a particular
category. Periodically, the computer 100 operates to make a
determination of the letter category which should next be unloaded
from the retaining stations 10 in order to accomplish an optimum
inventory reduction based on the letter content of the retaining
stations 10.
Data is also stored in computer 100 as to the time sequence of the
various events necessary to determine the location and content of
any receptacle 3 which has entered the apparatus In this regard,
operation of conveyors 40-44 is continuous and at constant rate so
that, with at least on reference point on each conveyor represented
by stored data, the relative position of any point on each conveyor
is determinable by the computer at any time during operation of the
apparatus. Since the time of each actuation accomplished under
control of the computer will be known, including, for example,
deposit of an empty receptacle 3 on input conveyor 40, and deposit
of a partially filled receptacle 3 on roller conveyor 41 by
recirculating conveyor 46, computer 100 can determine the position
and condition of all receptacles 3 which are delivered to the
apparatus throughout the entire time until the receptacle is
discharged onto off-bearing conveyor 44. It is to be noted
particularly that, following the procedures described in my U.S.
Pat. No. 3,312,949 the operation of the doors 11 of retaining
stations 10 is controlled so that letters of the selected address
category are dropped successively, with the succession proceeding
in the direction of travel of receptacles 3 on conveyor 42, and in
timed relation with the progress of a predetermined point or points
on conveyor 42 along the path established below the series of
retaining stations by the conveyor 42.
The position of each receptacle 3 on conveyor 42 is determined
precisely, so that, in effect, operation of computer 100 to open
doors 11 is timed in relation to the position on conveyor 42 of the
first notch 20' of each receptacle 3. Thus, the controlling action
of the computer 100 is such that, when a letter address category to
be unloaded has been selected and a receptacle 3 has been placed on
conveyor 42, either from conveyor 40 or from conveyor 46, the door
11 for the first station 10 in the series which contains a letter
of that category will be opened when notch 20' of the receptacle is
just short of having reached precise vertical alignment below that
particular retaining station 10, to allow for the very short free
fall time required for the letter to drop from its retaining
station to a position in which the bottom edge of the letter
engages the bottom wall of the receptacle 3. Conveyor 42 is so
positioned relative to the series of retaining stations 3 that each
letter drops, in free fall, through a distance that is not much
greater than the maximum width of the letters. Accordingly for
practical purposes, the letters retain their essentially vertical
disposition, initially determined by the confining action of
stations 10 and the guiding action of doors 11 during opening,
throughout their free fall, and the position of the bottom edge of
the dropped letter relative to notch 20' is therefore predetermined
within practical limits.
The bottom edge of the letter dropped from the first selected
retaining station will, therefore, come into engagement in notch
20'. Since the receptacle 3 is being advanced continuously by
conveyor 42, the letter so dropped into notch 20' will pivot about
its lower edge, with its upper edge swinging rearwardly, until the
letter comes to rest on the trailing end wall 16 of the receptacle
3.
Computer 100 similarly determines that the opening of door 11 of
the next retaining station 10 containing a letter of the proper
category will occur when the notch 20 next adjacent to notch 20' is
just short of precise vertical alignment with that particular
retaining station 10. Accordingly, the letter dropped from that
retaining station will drop vertically until its bottom edge
engages in that notch 20, this letter then pivoting rearwardly (as
the receptacle 3 continues to advance) until it comes to rest on
the first letter and is thus supported indirectly by end wall 16.
This operation is continued, under control of the computer, until
the receptacle 3 has advanced to the end of conveyor 42 and either
all letters of the selected category which had been retained in the
series of stations 10 have been dropped into the receptacle 3 or
the receptacle 3 has been filled to its capacity. In the latter
event, the the computer is programmed to assure that no further
letters of the selected category are dropped during passage of this
particular receptacle 3 along the series of stations 10, the
residue of letters of the selected category remaining in the
stations 10 until the computer again selects that category for
unloading.
A part of the data stored in computer 100 for control purposes is
the predetermined threshhold value of letters to be collected in
each receptacle 3, this value being the same for all receptacles
and being the reference for determining whether, when the
receptacle 3 reaches the end of conveyor 42, the device 52 is to be
operated to divert the receptacle to the first recirculating
conveyor 45 or is to be left unactuated until the receptacle 3 has
been passed by conveyor 43 onto the off-bearing conveyor 44.
Computer 100 is programmed to make a count of the letters actually
dropped into each receptacle 3 and to compare that count with the
predetermined threshhold value, the count being derived in the
manner disclosed in my U.S. Pat. No. 3,312,949. When the receptacle
reaches the delivery end of conveyor 42, that count is compared by
the computer with the threshhold value. If the actual count is more
than the threshhold value, the receptacle is simply allowed to
proceed over conveyor 43 onto conveyor 44, the device 52 remaining
inactive. If the count is less than the threshhold value, the
computer commands operation of device 52, in timed relation to
travel of the receptacle 3, so that arms 53 pivot upwardly and
fingers 57 of fork 56 engage the bottom of the receptacle and lift
the same to the position shown in broken lines in FIG. 2, so that
the next set of fingers 47 of conveyor 45 to arrive at that
position will, passing between the fingers of fork 56, engage the
bottom of the receptacle 3 and cause the same to be conveyed
upwardly.
The conveyor 45 thus receives only the ones of receptacles 3 which
have collected from device 2 a quantity of letters of known address
category which is less than the predetermined threshhold value.
Each receptacle 3 so received by conveyor 45 is carried upwardly
thereby, its position on the conveyor being known because of the
known timed relation of operation of conveyor 42, diverting device
52, and conveyor 45. Also stored in computer 100 is data indicative
of the state of each storage conveyor 65, i.e., whether the storage
conveyor is full or can accommodate an additional receptacle 3.
Accordingly, when the fingers 47 of conveyor 45 which support the
receptacle 3 pause at the input end of each storage receptacle 3,
the computer recognizes through its stored data whether the
receptacle can be transferred to the storage conveyor. If the
storage conveyor can not accommodate the receptacle, the receptacle
is simply advanced by conveyor 45 to the next storage conveyor. As
soon as the receptacle is brought by conveyor 45 to the input end
of the first storage conveyor 65 capable of accepting a receptacle,
the computer causes actuation of the corresponding transfer device
70 to push the receptacle off fingers 47 onto the input end of the
storage conveyor 65. If that storage conveyor contains no
receptacles, the receptacle 3 delivered thereto by device 70
advances until it is engaged and stopped by the stop device 75
associated with that storage conveyor. If the storage conveyor
already supports one or more earlier-arrived receptacles, the newly
arrived receptacle 3 advances until its end wall 16, now leading
because the receptacle is reversed with reference to travel,
engages end wall 17 of the receptacle last placed on the storage
conveyor. In either event, digital signals are stored in computer
100 representative of the position of the particular receptacle 3
on the particular storage conveyor 65.
During operation of the apparatus, the inventory of any particular
letter category in the series of retaining stations 10 varies
according to new letters of that category supplied via operation of
traverse cars 12 and unloading of letters of that category from the
retaining stations, and a continuing count of this inventory is
maintained a stored data in computer 100. Assuming that letters of
a particular category have been once unloaded into one or more
receptacles 3 and that one receptacle 3, containing an amount of
letters of that category less than the threshhold number, has been
diverted to one of the storage conveyors 65, and the inventory
count for that category is such that is is desirable to again
unload letters of that category, the program dominating operation
of computer 100 may call for unloading of the letters into one or
more empty receptacles from device 4, or for recall of the stored,
partially filled receptacle, or for both. Assuming the stored,
partially filled receptacle is to be recalled from storage,
computer 100 operates to actuate the stop device 75 of the
particular storage conveyor 65 on which the receptacle is
supported, the receptacles thereon being thus released and
delivered directly onto respective sets of fingers 49 of the second
recirculating conveyor 46. Each receptacle 3 so delivered by the
storage conveyor to conveyor 46 is identified by the computer and
such of the receptacles as may have been ahead of the recalled
receptacle 3 on the storage conveyor 65 are delivered, by conveyor
46 and the by-pass transfer device 70, to by-pass conveyor 51 to be
again delivered onto the same or a different storage conveyor 65
via conveyor 45. The recalled receptacle 3 is allowed to pass the
delivery end of by-pass conveyor 51 and is deposited by conveyor 46
onto roller conveyor 41. Conveyor 41 delivers the recalled
receptacle to main conveyor 42 and the receptacle is thus again
passed beneath the series of retaining stations 10 to receive
additional letters of the same category as those already in that
receptacle.
During the pass of the receptacle under the series of stations 10,
the computer operates to open the respective doors 11 in timed
relation to the travel of the first unoccupied notch 20 of the
receptacle, so that the first letter dropped falls into that notch,
and the group of letters is then built letter by letter as earlier
described. A count of the newly dropped letters is maintained by
the computer and added to the count of letters already in the
recalled receptacle, so that dropping of letters into that
receptacle can be terminated when the total of letters therein
reaches the threshhold value. If the total reaches the threshhold
value, the recalled receptacle is released via conveyor 43 onto
conveyor 44; if not, the receptacle can again be recycled to
storage as hereinbefore described.
It is thus apparent that the combination of conveyors 40-44
diverting device 52, recirculating conveyors 45 and 46, storage
conveyors 65, transfer devices 70, and stop devices 75, using the
receptacles 3, can be controlled automatically by computer to
cooperate with a code controlled sorter comprising devices 1 and 2
in such fashion as to overcome problems stemming from the fact that
the number of articles of a given category present in the sorter
may not be adequate to form a group to be delivered. The ability to
recycle partially filled receptacles through storage, so that each
receptacle is ultimately filled to a predetermined extent, makes it
possible to capitalize more fully on the high operating speeds of
which code controlled sorters, such as those shown in my U.S. Pat.
No. 3,300,066, are capable.
The method and apparatus are characterized by the capability of
providing "faced" groups of letters, that is, groups in which the
address faces of all of the letters face in the same direction, and
with the letters being in essentially the same condition as when
delivered to the sorter, that is, with no bending, crimping or
other damage having occurred during sorting, grouping and handling.
Thus, the receptacles 3 not only retain the letters in the same
faced relation in which they were delivered from stations 10 but
also protect the letters from damage as the receptacles are
handled, this latter capability being extended through such
post-sorting operations as shipping when two of the receptacles are
combined to form a complete enclosure, as in FIG. 7.
While the invention has been described with reference to a system
employing only a single optical character reader 1 and sorting and
storing device 2, it is to be understood that a plurality of such
devices can be used in serial multiplex so that the system will
have an enlarged throughput capacity without duplication of the
conveying, transferring, storing and control components. The
present invention therefore retains all of the advantages described
in my U.S. Pat. No. 2,863,574, issued December, 1958.
* * * * *