EP1872865A2 - Stacker module for flat postal items operating last-in/first-out - Google Patents

Abstract

The module (2) has a storage area comprising a splitting knife (18) with which two forces exercised antiparallel to a stacking direction (34) of a part of a mail piece (P1) stored in the area during existence of an establishing function, respectively. A feed stop (14) is moved in the stacking direction for producing a pull-off opening (16). The splitting knife is driven by an underfloor belt or separately, where one of the forces is adjusted based on a characteristic of an actually stored mail piece.

Description

The present invention relates to a memory module for flat mailpieces having a storage area and an inserting function that transfers mail pieces from a mailpiece stream into the storage area, and a print function that pulls mail pieces from the storage area.

With today's mail sorting systems, very large quantities of mailpieces have to be sorted and distributed in so-called mail centers and / or larger post offices. For example, the average daily mail volume in Germany is about 80 million letters, which should reach their addressees on the very next day, but at the latest on the day after the mail after the next. Such pieces of mail are referred to in the jargon as so-called Letters (English word for letters). Characteristic of these mailpieces is that the length and width of these mail pieces is generally large relative to their height. However, with regard to the definitive dimensions for the assignment of mail items to this group of Letters, there are sometimes significant differences among the postal administrations of the different national states. In addition to these size deviations, it is also easy to see that the nature of the mail pieces, even if they are all "Letters" may differ significantly from each other.

It is therefore easy to imagine that the processes of postal automation today have to be operated extremely efficiently and, in the context of cost pressure, also with a comparatively small number of operators. In order to achieve sufficiently high throughput rates in the sorting plants, the mail pieces are conveyed at speeds of up to 4 m / s or sometimes even more through the sorting system and their destination by appropriately switched points and a sophisticated, usually sorted multilevel Gangfolgesortierverfahren.

For the correct feeding of the mail items, it is therefore essential that the address of the mail piece can be at least at the beginning of the sorting process once recorded by machine. Often, however, the address can not be read by machine, but must be added by manual input of the address (or at least the part of it significant in the respective sorting operation). This fact requires that the mail items that can not be read mechanically have to be removed from the sorting process, buffered in a memory module and, after manual assignment of the address, have to be removed again from the memory and introduced into the sorting process.

In addition, there are of course many other constellations in the sorting process, such as an error in the sorting path, which necessitates that mail pieces be temporarily stored and later reintroduced into the sorting process.

The storage modules known today, which can contribute to a largely automated sorting process, usually work according to the first-in / first-out principle. The mail pieces, which are usually transported upright and resting on the long edge, are thus stored on one side of the stored stack, for example on the "top" of the stack, and on the corresponding opposite side of the stack (in the example selected terminology then on the "bottom") withdrawn from the stack. In this case, the stacking device acts on the stack beginning and on the stack end the removal device, which results in a kind of tensioned compression spring, which corresponds to the stack of mail pieces. It is obvious that, thus, both the stacking device and the take-off device in this constellation about the same average pressure sets. However To perform the task of stacking and peeling safely, it would actually require different pressures on the stacker and the trigger device. Thus, the compromise only adjustable mean pressure at both ends of the stack therefore repeatedly leads to process errors that manifest themselves, for example, in a folding or buckling or insufficient collection of mail pieces on the stacker and misprints or poorly aligned mail pieces on the trigger.

It is therefore an object of the present invention to improve a memory module such that the tasks of storing and removing can be performed with an extremely low process error rate.

This object is achieved by a memory module of the type mentioned, in which the insertion and the trigger function comprise a common roller belt unit and a Zuführanschlag, optionally the Einführfunktion or the trigger function is executable by in the Einführfunktion the mail pieces in the conveying direction of the roller belt unit of the roll band can be guided against the feed stop and can thus be transferred into the storage area, and by the last stacked mail item being able to be pulled off from the storage area in the discharge direction by a discharge opening from the storage area.

In this way, while using common components for the insertion and withdrawal functions, it is still possible to insert or store mail items in the stack and to pull out mail items which are usually conveyed in substantially vertical orientation at these stages of the process for convenience to separate functionally from the stack and thus be able to set the most favorable process parameters for each of the two processes. Unlike in the known in the prior art first-in / first-out operation (FiFo) can be achieved in this way a load-in / first-out operation, which is stored during storage focus on fulfilling the best possible margin conditions and deducting to meet the best possible margining conditions.

The particularly important for the storage feed stop, which makes it possible to center the mail pieces for subsequent accurate deduction on two side edges of the mailpiece, is rather counterproductive for the deduction function, because the mail pieces are continued with the deduction from the storage area, preferably in the original feeding direction should. The trigger function is therefore structurally particularly easy to implement if the supply stop in the stacking direction (direction in which the stack grows in the storage area) is displaceable in order to produce the trigger opening. The last stored mail pieces is therefore promoted by the roller conveyor unit substantially in the orientation of the mail piece in the storage area (or even promoted in a vectorial transition, which still has a noticeable components in Einspeicherorientierung) and can be fed, for example, in the current mail piece stream.

The contact pressures on the roller belt unit, which are optimized for the insertion function and the trigger function, can be implemented particularly well if the storage area comprises a separating knife with which a first pressure can be exerted antiparallel to the stacking direction on at least a portion of the mail pieces stored in the storage area in the presence of the insertion function, and with which in the presence of the trigger function, a second pressure antiparallel to the stacking direction on at least a portion of the stored in the memory area mailpieces is exercisable. In this case, the stacking direction refers to the direction in which the stack grows when mail pieces are continuously introduced into the storage area. Advantageously, this cutting knife can be driven by means of a lower belt edge or separately, which is in this way in the position, regardless of the stack size To produce a constant contact pressure for each brought to the roller conveyor unit mail pieces on the roller conveyor.

In a further advantageous embodiment of the invention, it can be provided to achieve particularly suitable Andruckbedingungen on the mailpieces that are currently promoted with the roller belt unit for storage or withdrawal, adjust the first pressure in dependence on at least one property of the currently stored mail piece and / / or to set the second pressure in response to at least one property of the last stored mailpiece. Such a property may be, for example, the thickness and / or the length of a mailpiece or the surface texture of a mail piece.

Typically, certain postal mail sorting machines will set certain mail item thresholds in coordination with a (postal) customer that can be processed by these sorting machines. Such limit are primarily the dimensions of the mail pieces, so their minimum and maximum width, length and height, and then in the second line, for example, also their weight or their external nature. The roller conveyor unit, which guides the mail pieces in the insertion function to the feed stop, can therefore be dimensioned in an advantageous embodiment of the invention so that a memory area facing portion of a roller conveyor unit included in the driven roller conveyor is shorter than a shortest by definition piece length. In this way, the storing operation can be assisted in that the roller tape does not engage the entire mail piece and so does not deliver the mail piece with the frictionally transmitted driving force too much against the feed stop, thereby causing process errors (buckled mail piece and blocking of the process) This point can be avoided even better.

A different starting position can be considered as given for the withdrawal of the mail items from the storage area become. After the stored mail pieces are arranged very cleanly centered on two edges in the storage area, there is a desire for the optimal further processing (further promotion) of the mail pieces to deduct the mail pieces very defined from the storage area. A previously mentioned parameter, which supports the deduction process, is the choice of the correct pressure of the last stored mail piece on the roller conveyor unit. This process can be supported particularly advantageous if, in the presence of the trigger function, at least one pivotable support roller is provided for supporting the last stored mail piece, wherein the at least one support roller is pivoted away in the presence of the insertion function. This at least one support roller, which actually only needed for the trigger function and is therefore pivoted in the trigger function, ensures that the entire mail pieces is designed substantially parallel to the conveying plane of the roller conveyor and thus the driving force of the roller conveyor very homogeneous on the with the roller conveyor in Contact part of the mailpiece can be transferred.

For the insertion function, in addition to an optimized first pressure, a number of further parameters can be identified to help avoid process errors. Such a parameter may be, for example, the feeding direction of the mailpieces to the roller conveyor unit. In an advantageous embodiment of the invention, therefore, the feed direction of the mailpieces in the mailpiece stream can be adjusted so that the feed direction extends at an angle to the orientation of the mail pieces in the storage area. In this way, the endeavor can be supported that the item of mail during the introduction into the storage area towards the end of this process is drivingly only in contact with the roller conveyor and thus a defined supply to the supply stop.

In a further advantageous embodiment of the invention, the roller conveyor unit driven by a servo motor Include roller tape. This is a shared roller conveyor available both in the insertion function and in the trigger function, which also has a structurally very beneficial.

Alternatively, it could also be provided that the roller conveyor unit comprises two separately driven roller conveyors, wherein one of the two roller conveyors in the Einführfunktion in frictional contact with the mail items to be stored and the other of the two roller conveyors in the trigger function in frictional contact with the deducted from the storage area Post pieces can be brought. In this way, for example, specified for the respective function roller conveyors can be used with different coefficients of friction. Constructively, however, this solution is a little more expensive, because a mechanism must be present, which brings the two different bands depending on the selected function in frictional engagement with the mail pieces. It is conceivable here, for example, a pivoting device, which pivots the one roller belt in a Reibkontaktposition, while at the same time the other roller belt is pivoted out of the Reibkontaktposition (and vice versa). A further alternative may also be an eccentric shaft, which raises the one roller conveyor in the frictional contact position and at the same time lowers the other roller conveyor (and vice versa).

Further, it is particularly advantageous if each of the above-mentioned roller belt can be driven by means of a servo motor, which drives the roller conveyor with a predeterminable profile. In this way it is possible, for example, to drive the mailpiece slower at the end of the insertion movement and thus bring it gently to the insertion stop. For very short mailpieces, even the interim pause of the mailpiece may be provided before it reaches the insertion stop. The breakpoint may be defined, for example, as a location at which the trailing edge of the relatively short mail piece (and thus also the leading edge important for correct positioning) is still sufficiently far from the Insertion stop is removed in order to then drive the mail piece with the Wiederantreiben the roller belt in the desired speed for the next mail pieces, before the slowdown is provided for the gentle approach to the feed stop.

For extensive decoupling of the frictional contact of the mail pieces with all components described above for conveying the mail pieces of the gravity of the mail pieces, it is provided in an advantageous embodiment of the invention to align the mail pieces substantially vertically and / or aligning lying on its long edge.

Further advantageous embodiments of the invention can be found in the remaining subclaims.

Figur 1

in schematischer Darstellung eine Aufsicht auf ein Speichermodul in Einführfunktion;

Figur 2

in schematischer Darstellung eine Aufsicht auf das Speichermodul gemäß Figur 1 in Abzugsfunktion;

Figur 3

in schematischer Darstellung eine Aufsicht auf zwei Momentaufnahmen in Einführfunktion zur Veranschaulichung des Steuerung des Rollbandantriebs.

Embodiments of the invention will be explained in more detail with reference to a drawing. Showing:

FIG. 1

a schematic representation of a plan view of a memory module in Einführfunktion;

FIG. 2

in a schematic representation of a plan view of the memory module according to Figure 1 in trigger function;

FIG. 3

in a schematic representation of a plan view of two snapshots in insertion function to illustrate the control of the roller conveyor drive.

It should be noted in the introduction that the plan views shown in FIGS. 1 to 3 illustrate the substantially vertical orientation of the mail pieces. In the figures 1 to 3, therefore, the top views always show only the top of the mail pieces.

FIG. 1 shows, in a schematic view, a plan view of a memory module 2 according to the invention, which operates in the insertion function in the representation shown. The memory module 2 comprises a memory area 4 in which mail pieces P ₁ , P ₂ , P ₃ ,..., P _n-1 are currently stored. In the illustration shown, the mailpiece P _{n will be} the next mailpiece transferred to the memory area 4. In the present case, this postal item P _n is fed between two supply belts 6, 8 to the storage module 2 in the direction of an arrow 10 - referred to below as conveying direction 10 - and then taken over by a roller conveyor 12 of the storage module 2. The roller conveyor 12 is driven in a controlled manner and conveys the mail pieces P ₁ , P ₂ , P ₃ ,..., P _n-1 to a feed stop 14, whereby the mail pieces P ₁ , P ₂ , P ₃ ,. P _n-1 then based on their front and bottom edge in a well-defined position in the memory area 4 are. The supply stop 14 blocks in the position shown in Figure 1 and a vent opening 16, which will be discussed in more detail in the description of Figure 2. An arrow 26 is therefore intended to indicate that the feed stop 14 is guided in the shown plan (downwards) to immediately in front of the roller conveyor 12.

For the exact positioning of the mail pieces P ₁ , P ₂ , P ₃ ,..., P _n-1 in the storage area 4, it is therefore essential that the mailpieces P ₁ , P ₂ , P _{3 ,. 1 are} brought into contact with the roll band 12 with a certain Zuführandruck. It can easily be seen that because of too low a feed pressure, only a delayed delivery of the item of mail currently to be stored, in this case item P _n , and an undesired overlap with an already following item P _{n + 1} could occur. This can have the effect that the mail piece P _{n is} no longer guided correctly to the feed stop 14. On the other hand, too high a feeding pressure with only a few rigid mail items can undesirably cause buckling or unfolding of the mail piece in front of the feeding stopper 14 with the consequence that the folded / unfolded mail piece may be smoothed by hand again. At the prevailing conveyor speeds of a few meters per second for the mail pieces (outside of the storage area 4, it is easy to see that each process disruption usually affects not just one piece of mail, but rather usually a whole series of mail pieces within a conveyor path.

To set a Zuführandruckes optimized in this regard, a separating blade 18 and a bottom flange 20 are provided, which are very finely adjustable in the insertion function of the memory module 2 in the stacking direction according to arrows 22, 24 are movable. By means of the separating knife 18, a first pressure is generated in anti-parallel to the stacking direction in order to set the desired Zuführandruck on the roller conveyor 12 for the promotion of the respective mail piece to be stored.

The memory module 2 further comprises a support roller assembly 28, which is pivoted in the insertion function shown in Figure 1 in an inactive state. An arrow 30 is intended here to illustrate the pivoting direction of the support roller assembly 28 by way of example.

Figure 2 now shows a schematic plan view of the memory module 2, which is operated here in the trigger function. Unlike the insert function, a number of components of the memory module are now in a different position. The support roller assembly 28 is now in eingeschwenktem active state, which is to be indicated with respect to the pivoting direction by an arrow 32. The support roller assembly 28 ensures that, above all, the next postal item to be deducted, here the mail piece P _n-1 is aligned in a plane substantially corresponding to the conveyor plane spanned by the roller conveyor 12 and also in the vicinity of the memory module 2 substantially corresponds to further funding orientation. In this way, the postal item to be deducted lies flat against the roller conveyor 12 and can be deducted defined.

Thus, a deduction of the stored mail items is possible, the Zuführanschlag 14 is in the trigger function in the drawing according to arrow 34 upwards moved away and thus releases the vent 16. The snapshot shown in Figure 2 shows the mail piece P _n , which is already fully withdrawn and conveyed in the direction of an arrow 36, and the mail piece P _n-1 , the front edge 40 of which passes straight through the discharge opening 16 and by a scraper 38 in contact the roller belt 12 is held. The scraper 38 supports the avoidance of double scoops, since its coefficient of friction is matched to the frictional torque acting on the roller conveyor and with a double trigger retains the mail item that is not in direct contact with the roller conveyor. So that the mail piece P _n could be conveyed with a very precisely defined orientation of its front edge and the mail piece P _{n-1 is} currently conveyed in this way, an optimized print-deduction pressure of the mailpiece is now set on the roll-band 12. For this purpose, a second pressure is built up in antiparallel to the stacking direction by means of the separating knife 18 (see arrow 42). The setting of the correct trigger pressure is also important in the trigger function for the prevention of process errors, because too low a withdrawal pressure, for example, can lead to unwanted slippage of the roller belt 12 and thus to an inaccurate promotion of the currently deducted mail piece. On the other hand, too high a withdrawal pressure can lead to a multiple deduction or even to jamming of the lower postal items in the drawing.

In order to ensure the largely vertical orientation of the items located in the memory area 4 mail items even with the progressive withdrawal of mail items, the underfloor belt 20 is driven in the direction of arrow 44 and moves so in cooperation with the biased separating knife 18 stored in the memory area 4 mail pieces.

Figure 3 shows a schematic representation of a plan view of two snapshots a) and b) during the expiration of the insertion function to illustrate the control of the drive of the roller belt. The snapshot a) "Stop" shows the situation for a short piece of mail P _X , before reaching the Zuführanschlags 14 is stopped. The trigger for stopping the roller belt 12 is a trailing edge 46, which reaches a border 48 drawn in dashed lines.

The snapshot b) "Start" accordingly shows the situation for a start of the roller conveyor 12. The mail piece P _n was stopped when it reached its rear edge 46 at the boundary 48. A now following at an angle α incoming mail piece P _{n + 1} makes it necessary that the mail piece P _n now, so to speak, free the place and is brought to the Zuführanschlag 14. The remaining distance is sufficient to bring a not shown servo drive for the roller conveyor 12 back to its desired rated speed and then gently decelerate for smooth arrival of the mail item P _n again. By these measures, the smooth shrinkage and accurate positioning of the mail pieces (even very short) is advantageously supported on the feed stop, whereby the process error rate can be further favorably influenced.

The memory module 2 according to the invention has thus been used to create a tool for post automation which provides process optimization for the feeding of mail items to a storage area and for the withdrawal of mailpieces from the storage area. Unlike the known in the prior art memory modules that operate on the first-in / first-out principle and thus always allow only a compromise for setting the parameters for the supply and withdrawal of the mail pieces, creates the load-in First-out principle here the possibility of this process automation, which works with much higher reliability than the devices known in the prior art.

Claims (12)

A flat mail piece storage module (2) (P ₁ , P ₂ , P ₃ , ..., P _n-1 ) having a storage area (4) and an inserting function that stores mail pieces (P _n ) from a mail piece stream (10) in the mail pieces Memory section (4) transferred, and a trigger function that deducts mail items (P _n ) from the memory area (4), wherein the insertion and the Abzugsfunktion a common roller conveyor unit (12) and a feed stop (14) include, and optionally the Einführfunktion or the deduction function is executable by the mail pieces (P ₁ , P ₂ , P ₃ , ..., P _n-1 , P _n ) in the feed direction of the roller conveyor unit (12) of the roller belt (12) against the feed stop (14) feasible and so in the storage area (4) can be transferred, and in the deduction function the last stacked mail piece (P _n ) in the conveying direction of the roller belt unit (12) through a vent opening (16) from storage area (4) is removable,
characterized in that
the memory area (4) comprises a separating knife (18), with which, in the presence of the insertion function, a first pressure antiparallel to the stacking direction (34) on at least part of the stored in the memory area (4) mail pieces (P ₁ , P _{2 '} P _3' . .., P _n-1 ) is exercisable and with the presence of the trigger function a second pressure anti-parallel to the stacking direction (34) on at least a portion of the memory area (4) stored mail pieces (P ₁ , P ₂ , P ₃ , .. ., P _n-1 ) is exercisable. Memory module according to claim 1,
characterized in that
for generating the draw-off opening (16) of the feed stop (14) in the stacking direction (34) is displaceable. Memory module according to claim 1 or 2,
characterized in that
the separating knife (18) by means of a lower belt edge (20) or can be driven separately. Memory module according to one of claims 1 to 3,
characterized in that
the first pressure is adjustable as a function of at least one property of the item of mail to be currently stored and / or that the second pressure can be set as a function of at least one property of the last stored item of mail. Memory module according to one of claims 1 to 4,
characterized in that
a portion of the roller belt unit (12) facing the storage region (4) is shorter than a postal item length which is defined as the shortest. Memory module according to one of claims 1 to 5,
characterized in that
at least one pivotable support roller (28) for supporting the last stored mail item (P _n-1 ) is provided in the presence of the trigger function, wherein the at least one support roller (28) is pivoted away in the presence of the insertion function. Memory module according to one of claims 1 to 6,
characterized in that
a feeding direction (10) of the mail pieces (P ₁ , P ₂ , P ₃ , ..., P _n-1 , P _n ) in the mail piece stream is at an angle (α) for aligning the mail pieces in the storage area (4). Memory module according to one of claims 1 to 7,
characterized in that
the storage area (4) comprises an underfloor belt (20), which in the stacking direction (22, 34) of the mail pieces (P ₁ , P ₂ , P ₃ , ..., P _n-1 , P _n ) or in anti-parallel to the stacking direction (34 ) of the mailpieces (P ₁ , P ₂ , P ₃ , ..., P _n-1 , P _n ) is movable. Memory module according to one of claims 1 to 8,
characterized in that
the roller belt unit (12) comprises a roller belt driven by a servo motor. Memory module according to one of claims 1 to 9,
characterized in that
the roller belt unit (12) comprises two separately driven roller conveyors, wherein one of the two roller conveyors in the Einführfunktion in frictional contact with the mail pieces to be stored and the other of the two roller conveyors in the trigger function in frictional contact with the from the memory area (4) deducting mail pieces can be brought. Memory module according to claim 9 or 10,
characterized in that
each roller conveyor (12) can be driven by means of a servo motor which drives the roller conveyor (12) with a predeterminable profile. Memory module according to one of claims 1 to 11,
characterized in that
the mail items (P ₁ to P _n ) are substantially vertically aligned and / or aligned on their long edge.

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