Note: Descriptions are shown in the official language in which they were submitted.
A DEVICE FOR DYNAL~IIC STORAGE OF FLAT OBJECTS
BACKGROUND OF THE INVENTION
This invention relates to a device for dynamic
storage of flat objects and more particularly of thin
objects such as, for example, letters (mail envelopes or
the like) or else checks, invoices, dispatch notes or
similar documents~
French patent No 77 05935 granted to the present
Applicant has already disclosed an installation for the
arrangement of sets of objects in stacks or in rows. In
this installation, a magazine equipped with a jog~ing
bench is associated with a plurality of intercalary
members. These members define a set of compartments with
the ~loor of the magazine and the skirtboards of the
jogging bench. The volume of these compartments is
determined by design. Conveying means comprising a chain
attached to the intercalary members permits forward dis~
placement of these compartments up to an unstacking head.
The comparbments of this installation are intended to
receive flat objects placed on edge such as mail envelopes,
for example, and the mechanism has the aesign ~unction of
bringing the objects towards an unstacking head during its
movement of forward travel.
In the ex~nple described r the above-mentioned
unstacking head is of the pnewnatlc type and comprises a
rotary extracting drum having an axis parallel to the
surface of the objects. A partial vacuum is applied to
the perforated wall of the extracting drum from a
stationary chamber connected to a source of fluid at
negative pressure. In consequence, the first flat obj~ct
to be brought into contact with this drum will be applied
against this latter by suction. The drum is driven in
rotation about its axis and causes extraction of the
aspirated object as a result of its movement of rotation.
Ancillary means are provided for retaining the object
which ~ollows the one being extracted. On the downstream
side of the drum, the belt conveyor collects the extracted
objects ~or subsequent processing. The operation is
repetitive in order to ensure withdrawal of all the objects
from a compartment, the compartments being unstacked in
succession.
In this installation, loading of the compart-
ments is carried o~lt by hand. In this case in particular,
the operator takes care to place the flat objects within
the compartments located nearest the unstacker as a
function of the stock which is present in the magazine.
One attempt o replace the operator has consisted in
placing a stacking head opposite to the first empty
compartment of the stock. Since the state of the stock is
variable, it proved necessary to design a movable stacking
head. The mobility of this stacking head, however, is the
, .
cause of many disadvantages. Bo-th a stacker and an un
stacker can in fact be equipped with a rotary drum, a
controlled-vacuum system and a set of actuators and
detectors. This configuration results in a high degree of
mechanical complexity in relation to the number o
components which have to undergo displacements. Diffi-
culties are also involved in the positioning or transfer
of intercalary members with a variable abscissa. A final
point is that, especially by reason of its inertia, the
step-by-step displacement o~ this assembly as a function
of repetitive stacking of objects results in unacceptable
deficiencies from the point of view o~ operational
reliability.
SUl~MARY OF THE INVENTION
The object oE the invention is to overcome the
disadvantages mentioned in the foregoing and in particular
to propose a device for large-capacity dynamic storage by
making use of a set of stationary stackers and unstackers
associated with a storage magazine for transporting
objects in an original manner.
The invention proposes a device for dynamic
storage of flat objects comprising a stacker for placing
all the objects to be stored on edge against each other
and within a storage magazine provided with successive
compartments delimited by intercalary means, said inter-
calary means being displaced by conveying means, and an
~2~ 7
unstacker for withdrawing the objects stored in the com-
partments. The distinctive feature of the invention l~es
in the fact that the stacker and unstacker are stationary
and that the intercalary means are independent of the
conveying means and are caused to cooperate in pairs with
said conveying means by retractable locking means in order
to form each time the front and the rear ends of one com-
partment aforesaid and in o~der to transport a correspond-
ing packet of objects along the magazine towards the unstacker
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. lA is a schematic diagram of the device
according to the invention.
Fig 5 . lB and lC show a mode of operation of the
conveying means of the device according to the invention.
Fig. 2 shows the arrangement of the control
means for the aforesaid mode of operation.
Figs. 3A, 3B, 3C, 4A, 4B, 5 and 6 show examples
of construction of the intercalary means according to the
invention.
Figs. 7A and 7B are flow diagrams defining the
operation of the conveying means.
In these different figures, the same reerences
designate the same eIements.
DESCRIPTION OF THE PREFERRED EMBODIMæNTS
There is shown in Fig. lA the general arrangement
137
of the storage device according to the invention. A
stationarily fixed stacking head or stacker 1 has the
function of stacking flat objects 3 on edge within a
magazine 2. The flat objects 3 are grouped together in
packets 4 by a set of intercalary means 5 and 6 and are
supported by the floor 7 of the magazine. One or two
jogging skirtboards located in planes parallel to the
plane of the figure on each side of the packets 4 complete
the construction o the moving compartments 8. The com-
partments thus formed are brought by a conveying means 9into contact with an unstacking head 10 or unstacker.
The operation of the dynamic storage device
according to the invention is as follows : at the time of
arrival of the flat objects which may take place in a
random order, the stackæ 1 stacks these objects within a
stacking compartment provided solely with a front inter-
calar~ means 6, so designated because it is located at the
front end of the packet as this latter passes through the
storage magazine. When stacking of the packet is
completed, which can be determined on the basis of either
a yiven number of objects to be stacked or a~"g~ven thick-
ness of the packet to be formed or a given waiting period
after stacking of the last object, a pair of rear inter-
calary means 5 and front intercalary means 6 is brought
~5 up to the rear of the packet which is being stacked. This
pair is then separated, with the result that the rear
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intercalary means 5 leaves with the formed packet whilst
the new front intercalary means 6 remains in a waitin~ or
standby position downstream of the stacker in order to
receive the fresh supply of objects to be stacked. The
compartment 8, the thickness of which is variable for the
reasons mentioned above, therefore travels through the
magazine and comes into abutting contact with the packets
which await unstacking and are contained in the storage
zone of the magazine. The storage zone of the magazine
designates a zone in which the packets can be stored
while awaiting unstac~ing.
As the unstacking operation takes place, an
unstacker 10 which is similar to the one described in the
foregoing withdraws the objects from the packets. During
this operation, all the stored compartments advance
towards the unstacker 10 at the same time and at the un-
stacking rate. Since the compartments are stored one
behind the other, pairs of front intercalary means 6 and
rear intercalary means 5 are re-formed. Durin~ forward
travel, when these pairs of intercalary means reach the
vicinity of the unstacking head 10, they are retracted in
order to permit withdrawal of the objects from the
f ollowing packet.
It is therefore apparent from the effects herein-
above described that the device accordin~ to the in~entionpermits dynamic storage of objects and also that the
. . .
37
stackers and unstackers are stationary. Finally, since
the rate of travel of the formed packets up to the poin~
of abutting contact with the last packets of the stock is
higher than the rate of stacking or unstacking, the
dev.ice according to the invention does not produce any
delay in processing by the unstacker 10 in the case of
flat ob]ects stacked by the stacker 1. This is the
situation which would prevail in particular if a station-
ary stacking head had been placed at the end of the
installation of the prior art cited earlier
In a very simplified embodiment of the invention,
the storage magazine is provided with only two front
intercalary means and two rear inte~calary means which are
arranged in alternate sequence and travel in a loop or
closed circuit 11. Moreover, the conveying means comprise
a single chain 17 which extends over the entire length of
the system and travels on a closed path. The chain
comprises a lug 18 applied against a yieldable catch-
strip 12 located beneath the lower end of the rear inter-
calary means 5. The rear intercalary means 5 thus com-
prise the yieldable catch-strip 12 attached to a carriage
15 which supports a set of thrust-fingers 13. In this
embodiment, the front intercalary means 6 comp~ise a
carriage 16 which supports a set of retaining-fingers 14.
The yieldable catch-strip 12 can consist of a steel blade
which has a predetermined degree of flexi~ility and is
.
8~
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applied against the lu~ 18 of the chain. When the packe-t
thus pushed forwards is abuttingly applied against the
stock which awaits unstacking~ the flexible catch-s-trip
is subjected to hiyh stress, bends back momentarily and
the chain lug escapes. The chain lug again escapes
beneath the catch-strip of the other rear carriage 15
which is waiting in the stock. The chain thus continues
to rotate, the packets being propelled towards the
unstacker in jerks each time the lug passes. By virtue of
the compression exerted on the objects contained in the
packets at the time of each forward displacement, the
reaction of these làtter is such as to exert a forward
thrust on the objects to be unstacked before a new com-
pression cycle is restored by the next passage of the
chain lug.
When the last object of a packet approaches the
unstacker, the pair of front and rear intercalary means
withdraws. This situation is made possible by a
distinctive feature of the fin~ers which will be con~
sidered hereinafter. The arrival of the conveyor-chain
lug initiates the forward displacement of the rear pair of
intercaLary means and the displacement of the front pair
of intercalary means in a return movement to a position
located upstream of the stacker l. The rear carriage 15,
which is placed in this case in front of the front
carria~e 16 is associated at this moment with said
carriage 16 by means of a latch mechanism. The pair
then continues to be moved by the chain to a point down-
stream of the stacking head, whereupon a cam releases the
latch mechanism and separates the pai.r thus formed. At
this moment, the chain lug displaces only the rear
carriage of the compartment which has just been formed
and brings this latter against the packet which is being
unstacked. The yieldable catch-strip 12 constitutes in
this case the retractable locking means according to the
invention. Stacking of fresh objects can also take place
during the same periods since a front intercalary means is
then in a wa.ting position downstream of the stacker.
In another mode of operation involving the use
of a single chain 17, the chain pushes the entire stock
towards the stacker at the unstacking rate. When a newly
stacked packet is ready to be directed to the stock, the
chain 17 performs one complete cycle. As it passes, the
chain places a new front carriage downstream of the
stacker, rapidly pushes towards the stock the packet which
has just been stacked and, after coming up against the
stock, continues to advance at the unstacking rate.
It is preferably ensured in accordance wlth the
invention that the number of intercalary means will not be
reduced to four but will be substantially greater, in
which case the conveying means are arranged differently.
These conveying means are shown in cross-section in Figs. lB
a41~3~7
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and lC directly beneath Fig. lA. In Fig. lB which is a
top view, the~e can be seen the stacking drum 1 and the
unstacking drum lOo There are also shown the thrust-
fingers 13 and the retaining-fingers 14, the semicircular
cross-section of which indicates that the rounded portions
of said fingers are in contact with the objects contained
in the compartments. There is also shown a jogging skirt-
board 19 located on the left-hand side with respect to the
direction of forward motion of the compartments (as
indicated by the arrow F). By means of the exploded view
of the packets of objects and of the stacking and un-
stacking drums, there can be seen a series of five chains
designated by the reference numerals 20 to 24. These
chains are arranged lengthwise in the direction of forwaxd
travel of the packets and are placed next to each other.
Each of these chains is driven by a motor which is in-
dependent of the motor of the other chains. Depending on
requirements, each chain is provided with one or a
plurality of retractable lugs represented by dashes or
short lines across the chains in Fig. lB and by small
teeth in Fig. lC.
In Fig. lC, the five chains mentioned above are
also illustrated but in a side view, that is to say in
exactly the same manner as the representation of Fig lA.
An active ~one of these chains is adapted to cooperate
with the carriages of the intercalary means. This zone is
t
located in one plane, namely the plane of the magazine
floor 7. For the sake of enhanced clarity of the
drawings, these chains have been arbitrarily shown at
different levels. It should nevertheless be undexstood
that the active top runs of the chains as illustrated
could be located in practice at the same level.
It is finally apparent from Fig. lB that each
carriage is fitted with at least three catch-strips. In
Fig. lB, these catch-strips are represented by dots
located in alignment with the fingers 13 or the fingers 1
of each carriage Said catch~strips are represented by
short rods in Fig. lC. The catch-strips of row 1 which
are designated by the reference 12.1 are adapted to co-
operate with the chain 20 or with the chain 21, depending
on the position of the carriage within the magazine. The
catch-strips of row 2 desiynated by the references 12.2
or 12.3 (depending on whether they are associated respect-
ively with a front carriage or with a rear carriage) are
adapted to cooperate respectively with the front transfer
chain 22 or the rear transfer chain 23. Finally, catch-
strips of row 3 designated by the reference 12.4 are
adapted to cooperate with the return chain 24. In this
embodiment of the intercalary means according to the
i~vention, it is therefore observed that these means are
provided with a set of fingers 13 or 14 for maintaining
the packets of objects, are provided with carriages 15 or
.118~
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16 which travel on the closed path or circuit 11, and ~re
actuated by a set of chains 20 to 24. When so required,
said intercalary means produce act:ion on the catch-strips
12.1 to 12.4 located opposite to said chains beneath the
carriages 15 or 16. The catch-strips which cooperate with
the retractable lugs constitute the retractable locking
means according to the invention.
The operation of this complex mechanism is as
follows : at the time of stacking of objects in the com-
partment which is being formed, the stacking chain 21travels at a speed which is made dependent on the stacking
rate and one of the retractable lugs 25 of the chain
pushes the catch-strip 12.1 of the front carriage of the
compartment which is being formed. When the contents of
the compartment are considered sufficient, the return
chain 24 fitted with a retractable lug 26 exerts a thrust
on the third-row catch-strip 12.4 of the front carriage 16
of the pair consisting of rear carriage and front carriage
and located in the waiting position upstream of the
stacker. Under the action of its high-speed forward
travel, the chain places the above-mentioned pair on the
downstream side o the stacker. The front carriage 16
thus placed in position performs the function of a front
carriage for a resh compartment whilst the preceding rear
carriage has the effect of closi~g the preceding compart-
ment.
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At this moment, the two rear an~ front transfer
chains designated respectively by the references 23 and 22
and each provided with a single retractable lug 27 and 28
respectively engage in the second-row catch-strips 12.3,
12.2 respectively of the packet which has just been com-
pletely stacked. In a combined movement of displacement
from the stacker to the unstacker, these two chains 22 and
23 hring the above-mentioned packet into position against
the existing stock. As they pass by, the first-row strips
12.1 of the carriages of said compartment withdraw the
lugs 25 of the chain 21. On completion of this operation,
the two chains 22 and 23 carry out a movement which is
reverse to the preceding and again come into their waiting
positions at the entrance of the stacker 1. They are thus
ready to repeat their action for the next compartment.
The fact that the chains are permitted to pass beneath
the second-row catch-strip 12.2 of the front carriage
which is in the waiting position is made possible by
withdrawal of their retractable lugs.
At the time of penetration of the transferred
compartment into the storage zone, the front-row catch-
strips 12.1 of the front carriage 16 or rear carriage 15
of the compartment 8 withdraw the retractable lugs 29 of
the unstacking chain 20. These retractable lugs revert
to their upright position as soon as the catch-strips 12.1
have passed. When the transferred compartment comes in~o
abutting contact with the stock and the front and rear
transfer chains withdraw, the last compartment to be
brought is thus processed by the unstacking chain, the
last uplifted lugs of which are now maintained respect-
ively against the first-row catch-strips of the front
carriages 16 or rear carriages 15 of said compartment.
The unstacking chain moves forward at the unstacking rate
and is controlled in dependence on this function.
As soon as a pair consisting of rear carriage
15 and front carriage 16 formed by buildup of comparbments
within the stock arrives in proximity to the unstacking
head at a distance which is equal, for e~ample, to one-
tenth of the height of the objects to be stored, a
mechanism which will be considered later in the description
permits withdrawal of the fingers. The rear-carriage and
front-carriage pairs continue, however, to be moved for-
wards by the unstacking chain. At the time of formation
of a fresh compartment by the stacker, the lug 26 of the
return chain 24 can then grip the aforementioned rear-
carriage and front-carriage pair on the downstream side
of the unstacker in order to recycle it to the stacker.
To summarize, the movements of the chains are
as follows : the stacking chain is controlled in
dependence on the stacker, the unstacking chain which
follows the stacking chain is controlled in dependence on
the unstac]cer, and the transfer chains have a seq~ential
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action in a reciprocating motion which is initialized by
formation of a fresh compartment. After positioning of a
rear-carriage and front-carriage pair downstream of the
stacker, the return chain 24 continues its movement and,
by means of its lug 26, is accompanied in its displace-
ment by all the pairs of rear carriages and front
carriages which have passed beyond the unstacker. To this
end, the structure of said chain 24 is such that its
active zone is located from the upstream end to the down-
stream end of the stac]cer in proximity to the unstackinglocation and on the return path of the circuit 11 which
connects the stacker to the unstacker. The last two
active zones in any case serve no purpose except in the
event that automatic recycling of the carriages is contem-
plated. Recycling, however, is not an essential require-
ment of the device according to the invention. By means of
a test device, the return chain 24 interrupts its action as
soon as any one pair reaches the waiting position upstream
of the stacker. By way of example, the test can consist
of transfer of any one of the catch-strips of one of the
carriages of said pair over a pedal 33.2 located upstream
of the stacker. During a movement in the opposite
direction, said return chain 24 accordingly comes into
position upstream of the stacker immediately behind the
first pair of carriages in the waiting position. This
movement in the opposite direction is made possible by the
-16
retractable nature of the lu~ 26.
In the embodiment herein described, the move~
ments of the different motors of the chains will be
controlled by a control logic circuit 32 appearing in
Fig. 2 and having two actions of different types. The
first of these actions consists in determining the thick-
ness of the packets to be formed. It was stated earlier
that the packet thickness could be fixed beforehand, in
which case it is known that this predetermined thickness
will be attained when the third-row catch-strip of a front
carriage finally passes over a pedal 33.1 as shown in
Fig. lB. There is every certainty in such a case that the
packets obtained will always have the same thickness. Since
the front and rear carriages both have third-row catch-
lS strips, it will cle æ ly be necessary to take one item ofinformation out of two. If the thickness of a packet is
to be determined by the number of envelopes, the pre-
determined positions (185) of a counter 30 associated with
the stacker 1 indicate the instant at which the packet is
completed. Finally, in the event of random stacking, it
may be decided to consider that a packet is any case
completed when a predetermined period of time has elapsed
after stacking of the last object. This time interval is
determined for example by the trailing edge of a pulse
delivered by a monostable multivibrator 31 which is
excited at each object-stacking operation~
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The control logic circuit 32 takes all these
indications into account. This circuit producss action
first of all on the return chain 24 in order to ensure
that it places a rear-carriage and ~ront-carriage pair on
the downst~eam side of the stacker and thus to permit
formation of a fresh packet. After a time-delay T which
has permitted completion of this action, the control cir-
cuit initiates startup of the motor of the front transfer
chain 22. Then, after a short-time delay ~T with respect
to the startup of said motor t the control circuit
initiates startup of the motor of the rear transfer chain.
This time-delay ~l is intended to permit the lug 28 of
the front transfer chain 22 which is in a waiting
position downstream of the stacker to pass across the
thickness o~ the packet which has just been formed and
even slightly more than this thickness in oxder to produce
a slight decompression of the packet which has just been
formed. The object of this operation is to facilitate a
complementary operation of jogging of packets against the
skirtboard 19 during transfer of the packet.
The second operation to be performed by the
control logic consists in continuously measuring the
position of the rear end of the stock within the storage
magazine 2. This position as measured with respect to the
upstream end of the unstacking head is a function, at a
given instant, o the thickness of the packets brought
., .
18-
into the magazine from the time o-f startup of the machine,
reduced by the distance traveled by the unstacking chain
from the same instant. The end-of-stock position having
thus been determined, the control logic stops the movement
of the front transfer chain 22 when it is considered that
the lug 28 of said chain has reached this position. The
control logic then stops the movement of the rear transfer
chain at a slightly later instant in order to ensure re-
compression of the packets of objects. The state of
compression of the packets can then be equal to or
different from the state which existed at the time of
formation of the packet. It is preferred in this
invention to ensure that all the chain~driving motors are
stepping motor~ which actuate the chains in such a manner
that a knowledge of the position of the motor entails
facto a knowledge of the position of the corresponding
chain.
In short, the control logic determines the thick-
ness o~ a packet according to the number of steps per~ormed
by the motor of the stacking chain from the time of initial
formation of said packet. The control logic is informed
as to the position of the rear end of the stock prior to
arrival of the fresh packet as a result of addition of the
thicknesses of the packets which have been stored, reduced
by the number of steps performed by the motor of the
unstacking chain. The control logic therefore"knows" the
37
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number of steps (in principle equal) which the front and
rear trans~er-chain motors have to per~orm in oxder to
ensure correct stockpiling.
Fig. 2 indicates that the positions of -the chains
20 and 2L are recorded by the control logic 32. Startup of
these chains is related to the operation respectively of
the stacking drum 1 ox unstacking drum 10.
In regard to the optional recycling operation,
the control logic must determine the state of empty
carriages available upstream of the stacker. This informa~
tion can be supplied to the control logic, for example by
causing a catch-strip of the carriages to pass over a pedal
correctly placed upstream of the stacker. By way of
example, the passage of a catch-strip 12.3 of a rear
carriage over a pedal 33.2 stops the operation of the
motor of the chain 24. In this manner r a rear-carriage
and front-carriage pair which is available for the
formation of a fresh packet is continuously maintained
upstream of the stacking head 1.
Suppression o~ the front transfer chain has no
effect on the operation of the dynamic storage device
according tG the invention. The result thereby achieved
is simply to reduce the mechanical operating range thus
obtained for the performance of the jogging operation. In
the same oxder of ideas, the stacking chain can be dis-
pensed with, provided in that case that the stacker is
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~lZ~
-20-
sufficiently powerful to exert a thrust on the packet
during formation in order to permit stacking of all the
objects. Finally, the rear transfer chain and the return
chain can be combined into a single chain, the operation
of which would be identical with the chain 17 of the
simplified alternative embodiment considered earlier. In
tllis case, the control logic is simplified and the un-
stacking chain permits uniform unstacking of the objects
contained in the packets.
Details relating to the front intercalary means
and rear intercalary means will now be studied with
reference to the following figures. Figs. 3A, 3B, 3C
represent a first type of the intercalary means under
consideration. There can be seen in Fig. 3A the jogging
skirtboard 19 2S well as t}le floor 7 of the magazine 2 as
shown in cross-section. The intercalary means 6 which is
illustrated comprises a carriage 16 and a set of retaining-
fingers 14. The carriage 16 travels on the closed path 11
materialized by the roller trac~s 34, 35 and 36 which
extend along the entire length of the magazine and on which
- the carriage 16 is supported by rollers 37. The arrange-
ment of the tracks 3~, 35 and 36 constructed of heavy
steel plate, or example, makes i-t possible to prevent
side-sway of the carriage as it travels through the entire
magazine.
In Fig. 3C, which is a sectional view in a plane
8~
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A looking on the top of the carriage 16, it is observed
that the carriage has a length, as measured in the
direction of displacement indicated by the arrow, of the
order of three or four times the diameter of the rollers 37.
In order to prevent pitchiny motion of the carriage during
transfer, sets of rollers 37 are mounted both at the front
end and at the rear end of said carriage. In Figs. 3A, 3B
and 3C, the carriage is thus provided with twelve rollers.
The retaining-fingers 14 which extend vertically
above the carriage advantageously pass through slots
formed lengthwise in the floor 7 of the magazine 2 Said
retaininy-fingers are attached to the carriage 16 by means
of a vertical fork 38 which is maintained within a bore 39
formed in the carriage. By virtue of the thickness of
said carriage, the fork 38 is capable of tilting neither
backwards nor sideways. In order to avoid rotation of
the fork 38 about its own axis, a pivot 40 which is
rigidly fixed to the carriage is in~erted within a hole 41
formed in the horizontal return 54 of the fork 38. Said
fork 38 is supported by a roller 42 on a roller-track 43
over the full length of the magazine. The roller 42 is
brought into contact with the track 43 by means of a
spring 44 which is applied on the one hand against the
carriage 16 and on the other hand against a flange formed
at the lowex end of the fork 38. In a preferred arrange-
ment according to the invention, the aforementioned spring
8~
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44 is a helical spring which surrounds the fork 38. In
order to complete the remarks made earlier, it should be
explained that the roller-track 43 withdraws in proximity
to the unstacking head. This makes it possible as a
result o expansion of the spring 44 to retract the
retaining fingers 14. During this operation, the pivot 40
slides within the hole 41 o the horizontal return 5~.
At the time of positioning of a rear-carriage
and front-carriage pai~ of this type on the downstream side
of the stackerr it is observed that the fingers of these
carriages are parallel to the objects to be stacked. In
order to prevent the fingers from sliding between the
objects, an ancillary mechanism applies a pallet against
these fingers during the stacking of the first objects
1~ which are about ten in number. Said ancillary mechanism
then removes the pallet since the rigidity of the ob~ects
already in position has become suf-ficient to guide the
fresh objects to be stacked. This pallet can consist of a
set of two fingers oriented at right angles to the fingers
13 and 14.
There can be seen beneath the carriage 16 two
catch-strips which correspond respectively to the catch-
strips 12.1 and 12.2 and are potentially useful or the
solution in which the transfer means comprise only two
chains. These two chains designated hy the reference
numerals 20 and 23 are shown in Fig. 3A and are supported
`:,'
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by roller-tracks 45 and 46. Said chains are provided
with retractable lugs 26 or 27 of a type indicated in
Fig. 3B In this figure, a rod-shaped lug 27 is mounted
by means of an articulation 47 on a link of the chain 23.
Said lug is shown in the retracted position. The movement
of the lug 27 is limited on the one hand in one direction
by a stop 48 and on the other hand in the other direction
by a spring 49 having calculated resilience. In this
example, said lug 27 constitutes the retractable locking
means according to the invention.
- There is also shown in Fig. 3A a set of rollers
50, 51 and 52 which are inserted so as to project to a
slight extent from the floor 7 of the magazine 2, with the
result that their generator-line is at a level slightly
above said floor. These rollers are placed lengthwise
along the magazine 2 and serve for the jogging operation.
The rollers shown in the figure are in fact driven in a
movement in the trigonometric direction and have the effect
of pushing the stored objects towards the jogging skirt~
board 19. In order to endow this operation with enhanced
effectiveness, the rollers 50, 51 and 52 are preferably
covered with a layer of rubber or any other material which
has comparable friction effects.
Fig. 3C shows that the carriage 16 as illus-
trated is a front carriage. In fact, for reasons of
overall size, the structure of the carriages considered is
,
, -
-24-
judiciously arranged so as to extend beneath the packet
which they are designed to convey. Thus in this figure,
the carriage which undergoes a displacement in the
direction of the arrow comes into contact with a rear
carriage, the thrust-fingers 13 of which are shown in
dashed lines. The cross-sections of semicircular shape of
these fingers exactly complete each other as they come
together. This arrangement is made possible by an offset
portion 53 of the fingers, this offset portion being per-
pendicular to the horizontal return 54 of the fork 38.The o~ientation of the offset portion 53 of the fron~
carriages is contrary to that of the rear carriages. When
the hole 39 is located at the mid-length of the carriage
16, the length of said offset portion is equal to the
half-length of the carriage. The length of the carriaye
is the dimension of this latter as measurea in the
direction of longitudinal displacement.
Figs. 4A and 4B illustrate ano~her example of
construction of a carriage. The essential feature of this
example lies in the fact that the roller-track followèd by
the front carriages as they travel on the circuit 11 is
different from the roller-track followed by the rear
carriages. In Fig. 4B r the front carriages 16 travel in
the direction of the arrow along the roller-track 5~
located on the left-hand side of the figure whilst the
rear carriages 15 travel in the same direction along the
-` ~2~
-25-
roller-track 55 located on the right-hand side of -the
figure. The roller-tracks 55 and 56 which suppor-t the
carriages essentially comprise in each case two solid
runways 57 and 58 which extend in a plane paralle] to -the
plane of the magazine floor 7. The two runways 57 and 58
of one roller-track are rigidly coupled together by means
of a flat arch 59.
In the example shown, the carriages are provided
with a T-section support member 60 which extends vertically
above the carriages and fits exactly within the space
provided between the runways 57 and 58 and the flat arch
59. The ends of the horizontal arms of the T-section
support members are fitted with rollers or needle
bearings 61. These bearings 61 are applied against the
runways 57 and 58 when a carriage is traveling during
transfer of a packet. Said needle-bearings serve to
support the carriage 16. In a comparable manner, the
central mast of the T-section support member 60 is located
between two needle-bearings 62 which are applied against
the oppositely-facing vertical side-walls of the runways
57 and 58.
It is apparent from a study of Fig. 4B that the
bearings 61 and 6~ are doubled so as to form two sets
located respectively in front of and behind the carriage
considered. The bearings 61 have the design func~ion of
preventing either side-sway or pitching movements of the
8~
-26-
carriage whilst the bearings 62 are intended to prevent
crabbing displacement of the carriage with respect to the
direction of forward travel within the magazine 2. In
fact, the running clearance provided for the bearings
5 within the space contained in the roller-tracks 55 or 56
is reduced to a minimum.
The carriages 15 and 16 thus travel along the
roller-tracks 55 and 56 respectively which are located
side by side. Each carriage is provided with a horizontal
cross-member designated respectively by the reference
numerals 63 and 66~ The cross-members extend over part of
the channel located between the roller-tracks and serve to
fix hollow posts designated respectively by the refexence
numerals 64/ 65 and 67/ 68~ The hollow posts are
oriented at right angles to the magazine floor 7 and are
pr~vided with bores which-extend vertically within said
posts from one end to the other in order to serve as
guides respectively for the fingers 13 or 1~ of the
carriages aforesaid. From the cross-sectional view of the
posts 63 and 66 and of the posts 64/ 65 and 67/ 68/
taker. in a plane parallel to the plane of the support
floor 7, it is apparent that the fingers 14 will lie in
the same plane as the fingers 13 as a result of an e~f~ct
of interengagement (as shown in Fig. 4B)o In consequence,
the interval between two juxtaposed compartments in the
storage line will be equal solely to the diameter of said
L8~
fingers 13 or 14.
The justification for the existence of these
two roller-tracks 55 and 56 lies in the need to set up
effective resistance to pitching motion of the carriayes.
Under the action of mechanical motion, this resistance is
directly rela~ed to the length of the carriages. In
respect of a given packet length, it has been established
that the length of the carriages of Fig. 4A can thus be
double the length of the carriages of Fig. 3A. The
length of each of these carriages can in fact be equal to
the total length of the packet whereas, in the previous
instance, it could be equal only to one-half the total
length of the packet.
Finally, there can be seen beneath the carriages
15 and 16 a set of toothed wheels 68.1, 68.3 for the rear
carriages 15, and a set of toothed wheels 68.1, 68.2 for
the front carriages 16. These toothed wheels are such
that, by means of a ratchet system, they are permitted to
rotate freely only in one direction with respect to their
axis but are prevented from rotating in the other
direction. In this application, the chains 20, 21, 22
and 23 fitted with ret~actable lugs will be replaced by
sprocket chains or slotted drive-belts. These slotted
drive-belts are adapted to cooperate with the correspond-
ing toothed wheels in accordance with the foregoingdescription. The "free-wheel" motion of these toothed
. .
-28-
wheels is indicated on the assumption that the carriages
are moving away from the person who is lookiny at Fig. 4A.
During the transfer stage, the toothed wheels 68.1 travel
on the double sprocket chain 20 used for the unstacking
operationO In consequence, the top of the toothed wheel
68.1 moves away from the observer while the center of
rolling motion is stationary. This arrangement is
indicated by a cross contained within a circle represent-
ing in schematic form the feathering of an arrow which is
traveling away from the observer. Similarly, it is shown
that, under the action of the return motion of the
transfer chains 22 and 23, the toothed wheels 68.2, 68.3
have a degree of freedom in the same direction as the
toothed wheels 68.1.
The return chain 24 is also replaced by a
slotted drive-belt. The position of this slotted drive-
belt is such that it comes into engagement for e~ample
with the toothed wheel 68.2 of the front carriage 16~ At
the same time, the drive-belt produces a for~ard displace-
ment of a rear-carriage and ront-carriage pair at the
time of operations which involve positioning of a fresh
carriage pair for stacking or at the time of recycling of
a carriage pair after unstacking.
The fingers 14 and 13 which slide respecti~ely
within the bores of the posts 67, 68 or 64, 65 are pro-
vided at their lower ends with shoes 70 and ~9
L8~
-29
respectively. These shoes are advan-tageously capable of
sliding within a slide-block 71 provided with two recesses
72 and 73. The top edges of said recesses are bent inwaxds
so as to form flanges 74. By bearing on the shoes 69 or
70, these top flanges have the effect of maintaining the
shoes 69 or 70 at the bottom of the recesses 72 or 73. In
order to cause withdrawal of the fingers 13 or 14 in
proximity to the unstacking head 2, the slide-block 71
undergoes a do~nward displacement with respect to the
plane of the magazine floor 7. The amplitude of this
downward displacement is slightly greater than the
apparent height of the fingers 13 or 14 above the floor 7.
By reason of the presence of the flanses 7~ at the time of
forward displacement of the carriage 15 or of the carriage
16, said flanges bear on the shoes 69 or 70 and thus cause
the fingers to move downwards. The downwardly displaced
position of the slide-block 71 is shown in dashed outline
in Fig. 4A.
Fig. 5 illustrates another example of con-
struction of ~he retractable fingers. The carriage shown
in this figure is identical with the carriage of Fig. 3~.
In this example of construction, the fingers have the
general shape of a scythe-blade comprising a handle 75
which ~xtends upwards from the carriage 15 to the magazine
floor 7 at a predetermined angle of slope. The fingers
consist of two flat blades 76 and 77 forming segments of a
: .
87
~o-
circular riny whose center coincides with the pivo-t point
0 of the handle 75. The two f]at blades 76 and 77
penetrate into the magazine through two slits designated
respectively by the reference numerals 78 and 79 and
formed longitudinally in the jogging skirtboard 19. When
the carriage moves, the objects placed on the support
floor 7 against the jogging skirtboard 19 are thus thrust
by the blades 76 and 77 in a direction at right angles to
the plane of the figure.
The retractable fingers are held in position
along the entire length of the magaæine as a result of
sliding displacement of the handle 75 along a guide rail
80. Contact is maintained between the guide rail 80 and
the handle 75 by means of a roller~bearing 81 which is
press fitted around the handle 75 and is adapted to run
along the guide rail 80. By virtue of its weight, said
roller-bearing also assists in maintaining the handle 75
in an inclined position. The guide rail 80 is cut in the
immediate vicinity of the unstacking head. At this point
and under the action of their weight, the handle 75 and
the blades 76 and 77 undergo a pivotal displacement about
an axis which is perpendicular to the plane of the figure
and passes through the point 0. It is noted that, in
this configuration as in the preceding configurations,
~5 withdrawal of the fingers always takes place in a
direction parallel to their own axes.
--31--
One example of an object 3 having a height h is
illustrated in ~ig. 5 in the ~orm of a ].etter or envelope.
The objects are not liable to be disturbed at the time of
withdrawal of the fingers since they are continuously held
in position by the jogging skirtboard l9 and by the
magazine floor 7. In fact, since these objects such as
envelopes are placed at right angles to the direction of
the longitudinal slits 78, 79, they cannot possibly pass
through these slits~ This arrangement is an advantageous
feature of the carriages since it guards against any
potential danger of misalignment of envelopes.
Fig. 6 is a sectional view showing the preferred
embodiment of carriages in accordance with the invention.
As in ~ig. 5 r the intercalary means in this instance
comprise fingers composed of flat blades 76 and 77 which
pass through slits 78 and 79 formed in the skirtboard 19
and joined to a handle. The handle has the shape of two
vertical se~ments 80 and 81 joined together by a hori-
zontal portion 82. The carriage proper has the shape of a
rectangular parallelepiped having an approximately square
section. As in the preceding examples, a set of pins
extending at right angles to the faces o~ said rectangular
parallelepiped are inserted within the interior of rollers
or needle-bearings 83 or 84.
The roller-track of the carriage as thus con-
structed has a complex shape. In two parallel horizontal
~32-
portions 86 and 87 located in oppositely-facing relation,
there is formed in each case a pair of grooves 88 and 89
which serves as a longitudinal housing for the rollers 83.
The two horizontal portions 86 and 87 are joined together
along one side by a vertical portion 90 which is per-
pendicular to these latter. A groove 91 is formed in said
vertical portion 90 and serves as a housing for bearings
84. In a position opposite to the portion 90 with respect
to the parallelepipedal carriage, there is fixed a vertical
portion 92 which is joined to the horizontal portion 87 but
not to the horizontal portion 86. There is formed in said
vertical portion 92 a groove 93 which is intended to serve
as a housing for a needle-bearing located opposite to the
bearing 84.
The guide rail thus formed for the roller-track
of the carriage of parallelepipedal shape has a longi-
t~ldinal clearance space 94 which permits the permanent
attachment of the vertical segment 81 to the parallele-
pipedal carriage. Along the length of this parallele-
2~ pipedal carriage as measured in the direction of its dis-
placement and ~s mentioned earlier with reference to
Fig. 3C, provision will be made for two sets of rollers ~3,
8~ in order to guard against pitching, side-sway and
pivotal displacement of the carriage. The carriage is
therefore provided in this case with eight rollers.
The guide rail hereinabove described terminates
31 2~
~33-
upstream of the unstac~ing head in a rotary barrel unit 95
constituted by a disk 96 on which are ~ixed at right
angles a plurality of identical elements 97 having a
sufficient length and the same cross-section as the guide
rail. The length of said elements is slightly greater than
double the len~th of one of the parallelepipedal carriages.
If the carriages are capable of interengagement in the
same manner as the horizontal cross-members 63 and 66,
this length is less than double the length of one oE the
carriages. In the example provided, said guide-rail
elements are four in number but it will be understood that
provision could be made for a different number. The
operation of the rotary barrel unit will now be explained.
When a rear-carriage and front-carriage pair thus arrives
in close proximity to the unstacker, it engages in a guide-
rail element 97 which is rigidly fixed to the rotary
barrel unit and forms an extension of the roller-track.
end-of-travel detector or alternatively the control logic
initiates a movement o~ rotation of the barrel uni 95 by
means of a motor ~not shown in the drawings). This move-
ment of rotation takes place through a predetermined angle
in such a manner as to ensure that another vacant guide-
rail element is placed in the line of extension of the
roller-track 86 to 94. In the example considered, this
angle is 90.
At this moment, the pair of carriages which has
37
-34-
been rotated is located opposite to a return roller-track
so as to permit recycling of the carriages to the stacker
It is apparent from a study of the figure that the
functions of the rollers 83 and 8~ have been reversed and
that the rollers 83 now serve to support the carriages. It
is observed that the blades 76 and 77 have been withdrawn
from their position as a result of rotation of the disk 96
about its center 0 and that said blades consequently no
longer interfere with the operation which involves unstack-
ing of objects of the following packet. Since the carriagewhich has just been reversed is taken away by the return
chain 24, it is possible to design a rotary barrel unit 95
provided with only one guide-rail element 97. After
removal of the reversed pair of carriages, the rotary
barrel unit returns to its position opposite to the roller-
track. By extension, in consideration of the fact that the
radius of rotation of the barrel unit is of substantial
length, the movement which is imparted to the carriage by
said unit becomes a movement of translation. In this case,
the blades 76 and 77 are straight.
As in the case of Fig. lC, the conveying means
of the preferred alternative embodiment of the invention
comprises a set of five chains. The sectional view of
Fig. 6 shows a pair of carriages in proximity to the un-
stacking head. A lug 29 of the unstac~ing chain 20 isapplied against a first-row catch-strip 12.1 of the
..
~21~7
. -35-
carriaye illustrated in order to constrain said carriage
to move towards the observer who is looking at the figure.
It is se.en that the front transfer chain 22 and rear trans-
fer chain 23 respectively located opposite to the second-
row catch~strips 12.2 and 12.3 do not cooperate at thismoment with these catch-strips since they are now in the
waiting position at the stacking head and their lugs 28
and 27 are no-t visible~ The action of the return chain 24
consists in pushing forward a pair of front and rear
carriages which has just been reversed by applying its lug
26 against the catch-strip 12.2 which, as has been noted
earlier, performs the function of a third-row catch-strip
12.4. However, if this had been made necessary by condi-
tions of limited space, it would have been possible to form
a third-row catch-strip 12.~ specifically installed or
the purpose of cooperating with the return chain 24. This
return chain 24 produces a movement of the carriages in a
direction parallel but opposite to those of the other
our chains although the axis of rotation of the drive
motor of said return chain is located in a plane parallel
to the floor 7 whereas the axes of rotation of the motors
which drive the other chains are perpendicular to said
floor 7.
Since the rotary barrel unit described in the
foregoing is located in proximity to the unstacking head,
the invention proposes to instal a barrel unit of the same
-36-
type upstream of the active generator-line of the stac~ing
head. The sequence followed b~ the rear-carriaye and ront-
carriage pairs is the same but reverse to the sequence just
described. In the proximity of the stacker 1, the unstack-
ing chain 20 is replaced by the stacking chain 21 which inany case cooperates with the front row catch-strip 12.1.
The stacking barrel unit will be judiciously placed in such
a manner as ~o ensure that the blades 76 and 77 are placed
respectively above and beneath the active portion of the
stacking drum 1 but slightly set back with respect to the
generator-line o~ this drum which is in contact with the
packet as this latter is being stacked.
Figs. 7A and 7B are flow diagrams of the transfer
function which is governed by the control logic 32. The
operational se~uence shown is the preferred case of the
invention and relates to an embodiment involving the use
of rotary barrel units and in which the return of the
carriages is arranged on a so-called rectangular circuit.
In this circuit~ the carriages undergo backward return
movements in contrast to carousel circuits in which the
carriages always travel back and forth in the same
direction.
The flow diagram of Fig. 7A relates to the
stacking stage. The two tests which are present at the
start of the flow diagram are performed cyclically by the
control logic. These two tests serve to determine the
state of the active or non-active stackiny drum and the
thickness of the packet of objects being formed. If the
drum is active and if the thickness of the packet within
the drum is between a minimum length and a maximum length
of predetermined value (for example between 75 mm and
150 mm)l it is necessary to close the packet in process
of formation by introducing a rear intercalary means and
to begin a fresh compartment b~ introducing a front inter~
calary means. This is obtained by causing the stackin~
barrel unit to rotate by one step.
Control of rotation of the barrel unit will take
place in a preferred manner in accordance with a law of
motion which ensures a correct rendezvous between the
retaining fingers and the letters which arrive at the
stacker. Initialization of this control operation is
produced by a sensor which detects the passage of the
trailing edge of the last envelope to be stacked. Intro-
duction of the new fingers takes place with a calculated
and constant time-lead with respect to the arrival of the
followin~ object.
For reasons mentioned earlier in connection
with the correct alignment of envelopes contained in the
magazine, startup of the front transfer chain will -take
place at an instan~ which allows a predetermined length of
time to elapse prior to startup o~ the rear transfer
chain. This time interval will be determined experiment-
-38-
ally. The time-delay governing startup of the rear
transfer chain with respect to the front transfer chain
may depend on the thickness of the packet to be formed and
on the logical possibilities of the control logic.
Stopping of the transfer chains can be produced by an end-
of-travel contact. By way of example, this end-of-travel
contac~ can comprise a pedal installed on the front
transfer chain and adapted to come into abutting contact
at a suitable point with the structure of a rear transfer
carriage at the time of encounter of these two carriages
within the storage magazine. Since the pedal constitutes
a switch, it usefully establishes a contact between two
flexible wires which terminate at the control logic~ Said
end-of-travel contact can also be obtained by means of a
device for measuring overvoltage at the terminals of the
drive motors of the front transfer chains and rear
transfer chains as the conveyed compartment comes up
against the existing stock. In fact, the variations in
the voltage-current characteristics of these motors can
be utilized to advantage in this manner. The order pro-
duced at this moment by the control logic initiates the
return of the transfer chains to their position upstream
of the stacking head.
Fig. 7~ shows the flow diagram corresponding to
the unstacking operation. When the unstacking barrel unit
is active, and when a rear-carriage and front-carriage
~2~ 7
-39-
pair penetrates into said barrel un~it, and when finally
there is no front-carriage and rear-carriage pair in the
bottom position of the barrel unit corresponding to
standby for recycling, forward displacement of the magazine
is then stopped for a period of time of predetermined
duration. This time interval serves to inhibit magazine
advance during the period of disengagement of the fingers
of the carriages and is initialized by control of the
jack which rotates the barrel unit. The unstacking
operation is then reswmed whilst the return chain 24
takes the pair of carriages which has thus been placed on
the return track in order to direct this pair to the
stacker.
It is wholly apparent that all these mechanical
operations take place with time-seLtings which are
adjusted experimentally. The position detectors which are
necessary for the ope~ation of the device according to -the
invention are of a type which is known to those versed in
the art and can comprise in particular photoelectric
cells. For example, the unstacking procedure will be
initiated only at the instant of occultation of a cell
which controls the forward displacement of the magazine.
Rotation of the barrel unit is permitted only when a cell
has confirmed the real presence of a carriage pair within
the barrel unit. Finally, the control logic is controlled
by a clock, the frequency of which is higher than the rate
of operation of the stacker or of the unstacker.
