EP0562954B1 - Device for feeding a stack of flat objects arranged on edge to an unstacking head of an automatic sorting system - 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.

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, unstacking of open folds, of the sheet type folded into several flaps or small advertising brochures or the like pose in particular unstacking difficulties, the conventional anti-double 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.

Document EP-A-416 490 discloses a device for feeding a stack of mail envelopes which makes it possible to solve these problems. This device notably includes a main magazine on which the stack of folds is placed and a pallet pushing the back of the stack, as well as an inclined secondary magazine.

• 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.

Thus, it is possible to adjust the levels of the main feeding belt and that of the support surface of the unstacking head at will; that is to say:

• 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 mat 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 conveying 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 clearly determined 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 arrangements, that the range of stackers 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.

Thanks to the inclined 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 low dispersion and an optimized flow rate as a function of that of the unstacking head.

The object of the invention is to further improve such a device for delivering mail folds to obtain a better presentation of the folds against the unstacking member. This object is achieved by a supply device as defined by claim 1.

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 seat of significant contact and bonding efforts.

The second limited fall of the pleats at the exit from 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 more reduced.

• 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;
• deux détecteurs disposés à proximité de la tête de dépilage contrôlent le niveau de remplissage à ce niveau et commandent l'avance des plis sur les magasins secondaire et principal;
• deux détecteurs disposés à proximité du bord aval du magasin secondaire contrôlent l'inclinaison des plis à ce niveau et commandent simultanément ou alternativement l'avance des plis sur les magasins secondaire et principal.

According to a preferred embodiment, the pre-depilation can be improved by the fact that:

• 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;
• two detectors placed near the unstacking head monitor the filling level at this level and order the advance of the folds on the secondary and main stores;
• two detectors placed near the downstream edge of the secondary magazine control the inclination of the folds at this level and simultaneously or alternately control the advance of the folds on the secondary and main magazines.

The functions and advantages of the invention 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 significant 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 gliding 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. By way of example, the height of fall may be approximately 55 mm and the distance between the edge of the sole 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 taps by eliminating any pre-depilatory ; the conservation of this inclination is ensured by the management of the main store 3 and of 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 m ³ / h) and 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, the latter will attract the next fold with a force which increases as the fold is displaced during unstacking and therefore 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 of 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 où 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 demand 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 stack 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 concealment of cells D1 and D2 where 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 (4)

1. A device for feeding a stack (1) of flat articles disposed on edge, especially mail items, to a de-stacker head (2) provided with a support surface (5), the device comprising:

   a) a main first feed magazine (3) extending substantially horizontally between first upstream and downstream ends thereof, said first magazine receiving the stack (2) of flat articles placed on edge and including means (4, 10, 12) for displacing the flat articles of the stack towards said first downtream end at a first feed speed;

   b) a second feed magazine (6) placed downstream from the first magazine and upwardly sloping between second upstream and downstream ends thereof, said second magazine receiving a packet of flat articles placed on edge and provided by the first magazine, said packet of flat articles being generally smaller than the stack of flat articles, said second magazine having means (14, 15, 16) for displacing the flat articles of the packet towards the second downstream end at a second feed speed; and

   c) a third feed magazine (11) placed downstream of the second magazine and extending substantially horizontally between third upstream and downstream ends thereof, said third magazine receiving flat articles disposed on edge from the second magazine in order to feed them in series to the de-stacker head;
      the device being characterized in that:

   d) the downstream end of the first magazine (3) is disposed above the upstream end of the second magazine (6) to create a first drop for the flat articles and the upstream end of the third magazine (11) is disposed beneath the downstream end of the second magazine (6) to create a second drop for the flat articles so as to rearwardly incline the flat objects disposed on edge in the second magazine; and

   e) first sensors (D1, D2) are provided for detecting the presence or absence of flat articles in the third magazine (11) and second sensors (D3, D4) are provided for detecting an inclined presentation of the flat articles in the second magazine (6), said first and second sensors being connected to control independently the first and second feed speeds of the flat articles in the first and second magazines respectively so as to maintain a correct filling rate in the third magazine and a correct inclined presentation of the flat articles in the second magazine.
2. The device according to claim 1, in which the first sensors comprising two photoelectric detectors (D1, D2) spaced substantially vertically close to the downstream end of the third magazine and the second sensors comprising two photoelectric detectors (D3, D4) spaced substantially vertically close to the downstream end of the second magazine.
3. The device according to claim 1, in which the third magazine is provided with at least one roller (8) driven in rotation to displace the flat articles from the upstream end to the downstream end of the third magazine.
4. The device according to claim 1, further comprising a blower jet (9) mounted above the third magazine for arranging said flat articles placed in said third magazine in a fan-shape.

Images