EP0562954A1 - Device for feeding a stack of flat objects arranged on edge to an unstacking head of an automatic sorting system and method for implementing this device - Google Patents

Abstract

The present invention concerns a device for feeding a stack of flat articles on edge, especially mail items, to a de-stacker head provided with a support surface, the device comprising a main feed magazine in which the stack is disposed and a plate pushing the rear of the stack. A secondary feed magazine is introduced between the main magazine and the support surface of the de-stacker head, the secondary magazine having an upwardly inclined transfer surface, its edge adjacent to the support surface of the de-stacker head being higher than the latter.

Description

The present invention relates to a device for feeding a stack of flat objects, in particular mail folds on edge to a unstacking head provided with a support surface, device comprising a main feed magazine on which the stack and a pallet pushing the back of the stack.

In order to obtain the proper functioning of a destacker, it is imperative that the feeding device associated with it ensures correct presentation of the mail.

Several technical problems arise at the level of a depilation head.

First, the rate of deteriorated or torn items should be minimized; in particular, the unstacking of open folds, of the sheet type folded into several flaps or small advertising brochures or the like, in particular pose difficulties of unstacking, the conventional double anti-grip systems by braking causing jams or tearing of the folds.

Second, the throughput, i.e. the number of plies processed per hour of operation, must be maximized.

Third, the rate of multiple catches caused by non-separation of the plies must be minimized.

Fourth, the dispersion over the frequency of injection into the sorting system must be optimized; more precisely, in the case of an injection with deviations between plies, account must be taken of the repetitivity of the deviation between plies (distance between rear edge and front edge) or of the pitch (distance between front edge and front edge) and respect a minimum difference which is a value conditioned by the performance of the sorting system; in the case of an injection with a pleating tiling principle, the repeatability of the covering value must be considered.

Furthermore, the known feeding devices are either of low capacity or compartmentalized, which results in difficult loading of the mail and a time of significant loading and therefore a decrease in profitability.

The present invention solves these problems, whatever the length of the stack of plies to be treated which can be very large and, moreover, by presenting an ergonomic zone for loading the plies.

• d'avoir le tapis principal à un niveau inférieur à celui de ladite surface support;
• d'avoir le tapis principal à un niveau supérieur à celui de ladite surface support;
• d'avoir le tapis principal et ladite surface support au même niveau.

In addition, thanks to the invention, it is possible to adjust the levels of the main feeding belt and that of the support surface of the unstacking head at will; it is therefore possible:

• to have the main carpet at a level lower than that of said support surface;
• to have the main carpet at a level higher than that of said support surface;
• to have the main carpet and said support surface at the same level.

This is in particular advantageous when the device is intended to equip an automatic sorting machine allowing the preparation of the postman's tour.

Indeed, such a machine generally comprises a device or feed store on which the operator installs the mail to be treated, a destacker whose role is to separate the folds one by one to bring them on a conveyor system, a head reader associated with a microprocessor and placed next to the conveyor system to identify each fold and assign a storage area corresponding to its final destination, a series of storage areas (called stackers), each representing a well-defined sorting destination .

For the postman's tour, sorting is carried out in three successive passes (explained in French patent application No. 90 12750 filed by the Applicant). The operator must therefore rearrange the folds twice on the feeding device, imperatively keeping a certain order. It is therefore important, to facilitate these set-ups, that the stacker range is at the same level as that of the feeding device. To make such a sorting machine, it is therefore essential that the level of the pleat support surface of the destacker is also at the same level, in order to allow a flow of objects without rising gradient.

To solve these problems, according to the invention, a secondary feed magazine is interposed between the main magazine and the support surface of the unstacking head, this secondary magazine having a transfer surface inclined upward, its edge adjacent to the support surface of the unstacking head being higher than the latter.

Thanks to this rising secondary magazine, the performance of the machine is improved, because it guarantees that the object to be unstacked is correctly placed against the unstacking member and therefore the rate of damaged folds is low, as well as the rate of multiple catches. ; and this at the required time, which results in a low dispersion and an optimized flow rate as a function of that of the unstacking head.

These results are obtained thanks to the pre-separation function of the secondary magazine which eliminates any compression of the objects which are on the contrary predisposed to allow a correct presentation against the unstacking member.

According to another characteristic of the invention, the edge of the secondary magazine adjacent to the main magazine is lower than the transfer surface of the latter.

The first limited fall of the folds at the entrance to the secondary store, driven by its own motorization, initiates the pre-separation of the folds and creates a first discontinuity which allows dissociation and backwashing of the objects. The length of the pile of folds on the main carpet in fact makes this pile the site of significant contact and bonding efforts.

The second limited fall of the folds at the exit of the secondary store completes the pre-separation, which is facilitated by the short length of the stack which passes through it, the forces between plies being reduced.

• au moins une chambre à faible dépression est associée à la tête de dépilage, plaquant le premier pli contre celle-ci;
• la surface support de la tête de dépilage est pourvue d'au moins un rouleau entraîné en continu en rotation, faisant saillie tout au long de ladite surface et tournant à ce niveau du magasin secondaire vers la tête de dépilage;
• une rampe de soufflage est disposée au-dessus de la tête de dépilage et dirigée vers la surface support de celle-ci.

According to a preferred embodiment, the pre-depilation can be improved by at least one of the following characteristics:

• at least one low vacuum chamber is associated with the unstacking head, pressing the first fold against it;
• the support surface of the unstacking head is provided with at least one roller driven continuously in rotation, projecting along said surface and turning at this level from the secondary magazine towards the unstacking head;
• a blowing ramp is arranged above the unstacking head and directed towards the support surface thereof.

The functions and advantages of these characteristics will appear on reading the following description of a preferred embodiment of the invention.

In order to optimally manage the movement of objects, the pallet and the magazines, main and secondary, can be operated independently thanks to detectors.

The invention also relates to a method of implementing the device equipped with such detectors.

More precisely, according to this method, two detectors placed close to the unstacking head monitor the filling level at this level and control the advance of the folds on the secondary and main magazines.

Furthermore, two detectors arranged near the downstream edge of the secondary magazine control the inclination of the pleats at this level and simultaneously or alternately control the advance of the pleats on the secondary and main magazines.

The functions and advantages of these characteristics will appear on reading the following description.

The invention is illustrated by two figures.

Figure 1 shows a device according to the invention, in side view.

Figure 2 is a partial view of Figure 1, on a larger scale.

• un magasin principal 3,
• un magasin secondaire 6,
• un magasin dit de prédépilage 11.

The feeding device comprises three sub-assemblies:

• a main store 3,
• a secondary store 6,
• a store known as pre-depilatory 11.

The main magazine 3 is substantially horizontal and the stack of folds 1 is placed there on edge, the lateral edge of the folds being in abutment against a jogging edge 13 common to the entire feeding device. The rear of the stack is pushed towards a destacking head 2, located opposite downstream of the feeding device, by a pallet 4 slidingly mounted on a substantially horizontal support rod 10 and going to the downstream edge of the magazine secondary 6.

The main magazine 3 has a belt 12 making the entire width of the magazine. The pallet 4 and the belt 12 are actuated at the same speed and motorized by a clutch-brake arrangement not shown EF2, for example by a motorized chain. This movement is managed by detectors D1 to D4 as will be seen below. .

This arrangement of the main store has the following advantages; it consists of an ergonomic loading area without compartments to be filled by the operator and it has a uniform mail contact surface consisting of only one belt, which allows easy handling and sliding of the mail; moreover it is of large capacity, for example it can be of a length of approximately 4.35 meters which is equivalent to approximately 3000 letters.

The secondary magazine 6 is interposed between the main magazine 3 and the pre-depilatory magazine 11. It consists of a sliding sole 17 inclined at an angle γ which can be about 8 ° and three belts 14 in contact with the sole 17 and driven via the axes 15 and 16 by a motor, not shown, equipped with a clutch-brake arrangement EF1. The jogging plate 13 is the same as that fitted to the main magazine 3.

The upstream edge of the secondary magazine 6 adjacent to the main magazine 3 is lower than the active surface of the latter, for example by about 30 mm. The edge adjacent to the pre-depilatory magazine 11 is higher than the support surface 5 of the unstacking head 2 in order to produce a fall of the objects and is at a distance from the face of the unstacking head 2 of a few centimeters thus creating said pre-depilatory magazine 11. As an example, the height of fall may be approximately 55 mm and the distance between the edge of the hearth 17 and the face of the unstacking head approximately 50 mm.

Thanks to this arrangement, the secondary magazine 6 ensures a division of the stack of letters just upstream of the unstacking head 2, forming a small packet of folds partially dissociated from the rest of the stack disposed on the main magazine 3, and a presentation adequate mail by slightly tilting the fold backwards; in fact, this inclination before the actual unstacking and during the feeding phase of the pre-depilatory magazine 11 prevents the letters tilting forward against the unstacking head 2 which would lead to a greater number of multiple takes by eliminating any pre-depilatory ; the conservation of this inclination is ensured by the management of the main store 3 and the secondary store by means of the detectors D3 and D4 and of the clutch-brakes EF1 and EF2 associated with the two stores, as will be specified below.

• d'avoir le tapis principal et ladite surface support au même niveau,
• d'avoir le tapis principal à un niveau inférieur à celui de ladite surface support,
• d'avoir le tapis principal à un niveau supérieur à celui de ladite surface support.

Another advantage of this inclined secondary magazine arrangement 6 is that it is possible to obtain any desired configuration as regards the relative position of the levels of the main magazine 3 and the support surface 5 (or of the pre-depilatory magazine 11). to know:

• to have the main mat and said support surface at the same level,
• to have the main carpet at a level lower than that of said support surface,
• to have the main carpet at a level higher than that of said support surface.

The pre-depilatory magazine 11 includes the support surface 5 of the unstacking head which is made up of a sole at the bottom of the pleats, reference for the level of unstacking. This sole is perforated to allow the projecting passage of rollers 8 controlled in rotation preferably continuously during the unstacking phase. They receive the folds that fall from the secondary magazine 6, slightly compress the feet of the folds against the face of the unstacking head 2, which arranges the folds in a fan shape with openings upwards. For example, the rollers 8 can have a speed of 0.5 m / s, a diameter of 80 mm and protrude from the bottom 5 of 6 mm.

The pre-depilatory magazine also includes a low suction chamber 7 through the face of the unstacking head 2. This suction is obtained by a high flow turbine (for example of the order of 300 m³ / h) and d '' a low level of depression (for example 7 mbar), which allows it to press the first fold of the pre-depilatory magazine 11 against a static area of the face of the unstacking head 2.

This low suction chamber 7 is supplemented by a high suction chamber 18 with a lower flow rate and a lower vacuum level, having the function of ensuring correct plating of the larger plies (in particular the first catalog pages) against the face of the unstacking head 2.

The pre-depilatory magazine 11 finally comprises an upper blowing ramp 9 (of a pressure for example of the order of 0.8 bar) disposed above the first plies, against the face of the unstacking head 2 and the jet directive has the role of accentuating the spreading of the folds, finalizing the separation between the first and the second fold to be unstacked.

When the first fold is unstacked, it gradually leaves the face of the head 2 according to its speed-up law. When its rear edge releases the suction chamber 7, this will attract the next fold with a force which increases as the fold is displaced during unstacking and therefore as the suction chamber 7 is released. After a relatively short time, but which may vary depending on the dimensions and weight of the folds, the next fold is placed against the face of the head 2, pre-separated from the rest of the pack and ready to be unstacked. This phenomenon of pre-separation will be linked throughout the depilation.

The detectors D1 and D2 manage the filling level of the pre-depilatory magazine and control its supply via the secondary magazine 6 if necessary as will be seen below.

The method of implementing the device will now be described.

The management of the main magazine 3 and the secondary magazine 6 allow correct supply of the pre-depilatory magazine 11. This management is ensured by the detectors D1 to D4 and by means of the actuators EF1 and EF2 of the two magazines in question.

The detectors D1 and D2 are barrier photoelectric cells and control the filling level of the pre-depilatory magazine 11. They are located at two different heights and close to the face of the unstacking head 2.

The detectors D3 and D4 are also barrier photoelectric cells and control the inclination of the mail at the downstream edge of the secondary magazine 6, before the folds fall in the pre-depilatory magazine 11. They are located slightly spaced in height near this edge.

When the filling level of the pre-depilatory magazine 11 is correct, the cells D1 and D2 are obscured, the clutches E1 and E2 are deactivated and the brakes F1 and F2 are activated. There is then no advance from the secondary 11 and main 6 stores.

When the filling level is incorrect, cells D1 and / or D2 are deactivated. In this case, a supply of folds is ordered and therefore an advance of the magazines 11 or / and 6.

• 1)Inclinaison correcte des plis:
     la cellule D3 est désoccultée et la cellule D4 est occultée; la demande de plis par le couple de cellules D1 et D2 se traduit par une avance simultané des magasins secondaire 6 et principal 3 (et de la palette 4 associée) c'est-à-dire les embrayages E1 et E2 sont activés et les freins F1 et F2 désactivés jusqu'à ce que les cellules D1 et D2 soient occultées.
• 2)Inclinaison incorrect, plis trop verticaux:
     la cellule D3 est occultée et la cellule D4 est occultée; la demande de plis par le couple de cellules D1 et D2 se traduit par une avance du magasin interface seul c'est-à-dire que l'embrayage E1 est activé, le frein F1 désactivé, l'embrayage E2 désactivé et le frein F2 est activé jusqu'à occultation complète des cellules D1 et D2; le nombre d'avances successives du magasin secondaire seul résultant de la demande du couple de cellules D1 et D2 est préférentiellement limité à trois; si à la demande suivante de plis, on constate pour le quatrième fois consécutive que le courrier est toujours trop vertical (cellules D3 et D4 occultées) alors on commande une avance simultanée des magasins secondaire et principal afin de ne pas créer de perturbation dans la pile de plis au niveau de la jonction entre les deux magasins.
• 3)inclinaison incorrect, plis trop inclinés vers l'arrière:
     la cellule D3 est désoccultée ou occultée et la cellule D4 est désoccultée; la demande de plis par le couple de cellules D1 et D2 se traduit par une avance simultanée des magasins secondaires et principal jusqu'à occultation des cellules D1 et D2 ou seul le magasin secondaire est arrêté c'est-à-dire l'embrayage E1 désactivé, le frein F1 activé, l'embrayage E2 activé et le frein F2 désactivé; le magasin principal est encore commandé pendant un laps de temps (égal de préférence à 200 ms, la vitesse linéaire des courroies du magasin secondaire étant de 90 mm/s et celle de la courroie et de la palette du magasin principal étant de 70 mm/s).

With regard to the inclination α of the folds in the secondary magazine 6, three cases may arise.

• 1) Correct inclination of the folds:
  cell D3 is obscured and cell D4 is obscured; the request for folds by the pair of cells D1 and D2 results in a simultaneous advance of the secondary 6 and main 3 stores (and of the associated pallet 4), that is to say the clutches E1 and E2 are activated and the brakes F1 and F2 deactivated until cells D1 and D2 are hidden.
• 2) Incorrect inclination, folds too vertical:
  cell D3 is obscured and cell D4 is obscured; the request for folds by the pair of cells D1 and D2 results in an advance of the interface store alone, that is to say that the clutch E1 is activated, the brake F1 deactivated, the clutch E2 deactivated and the brake F2 is activated until D1 and D2 cells are completely obscured; the number of successive advances from the secondary store alone resulting from the request for the pair of cells D1 and D2 is preferably limited to three; if at the next request for folds, we note for the fourth consecutive time that the mail is still too vertical (cells D3 and D4 obscured) then we order a simultaneous advance of the secondary and main stores so as not to create disturbance in the pile of folds at the junction between the two stores.
• 3) incorrect inclination, folds too inclined backwards:
  cell D3 is deactivated or occulted and cell D4 is occulted; the request for folds by the pair of cells D1 and D2 results in a simultaneous advance of the secondary and main magazines until occultation of cells D1 and D2 or only the secondary magazine is stopped, that is to say the clutch E1 deactivated, brake F1 activated, clutch E2 activated and brake F2 deactivated; the main magazine is still ordered for a period of time (preferably equal to 200 ms, the linear speed of the belts of the secondary magazine being 90 mm / s and that of the belt and the pallet of the main magazine being 70 mm / s).

Claims (8)

1) Device for feeding a stack (1) of flat objects, in particular mail folds on edge to a unstacking head (2) provided with a support surface (5), device comprising a feed magazine main (3) on which is placed the stack and a pallet (4) pushing the rear of the stack, a secondary feed magazine (6) being interposed between the main magazine (3) and the support surface (5) of the unstacking head, this secondary magazine having an upwardly inclined transfer surface, device characterized in that the edge of the secondary magazine, adjacent to the support surface (5) of the unstacking head being higher than the latter. 2) Device according to claim 1, characterized in that the edge of the secondary magazine (6) adjacent to the main magazine (3) is lower than the transfer surface of the latter. 3) Device according to claim 1 or 2, characterized in that at least one low vacuum chamber (7) is associated with the unstacking head (2), pressing the first fold against it. 4) Device according to any one of the preceding claims, characterized in that the support surface (5) of the unstacking head (2) is provided with at least one roller (8) driven continuously in rotation, projecting entirely along said surface (5) and turning at this level from the secondary magazine (6) towards the unstacking head (2). 5) Device according to any one of the preceding claims, characterized in that a blowing ramp (9) is arranged above the unstacking head (2) and directed towards the support surface (5) thereof . 6) Device according to any one of the preceding claims, characterized in that the pallet (4) and the stores, main and secondary, are operated independently using detectors (D1 to D4). 7) A method of implementing a device according to claim 6 characterized in that two detectors (D1, D2) disposed near the unstacking head (2) control the filling level at this level and control the advance folds on the secondary (6) and main (3) stores. 8) A method of implementing a device according to claim 6 or 7 characterized in that two detectors (D3, D4) disposed near the downstream edge of the secondary store (6) control the inclination of the folds at this level and simultaneously or alternately control the advance of the folds on the secondary (6) and main (3) magazines.

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