EP1446345A1

EP1446345A1 - Device for stacking flat objects such as postal covers

Info

Publication number: EP1446345A1
Application number: EP02801933A
Authority: EP
Inventors: Didier Thieriot; Laurent Baufreton; Serge Vignes
Original assignee: La Poste (Exploitant Public)
Current assignee: La Poste (Exploitant Public)
Priority date: 2001-10-26
Filing date: 2002-10-23
Publication date: 2004-08-18
Also published as: WO2003035527A1; FR2831530B1; FR2831530A1; JP2005506259A

Abstract

The invention concerns a device comprising successively: a first conveyor belt (10) receiving the flat objects in bulk; a hopper (20) wherein the dropped flat objects take up a substantially vertical position; a second sloping conveyor belt whereof the upstream portion constitutes the base of the hopper (20), and whereof the speed and the slope are selected so that the objects are placed therein supported on a wide edge; opposite lateral means, downstream of the hopper (20) and above said second belt, to form therewith a narrow passage for the objects, and for drawing the packets of objects so as to offset their front edges constantly in the same direction; a passage between rollers for projecting the objects with their wide horizontal edges and with transverse inclination corresponding to an angle of inclination of the stack, and oriented towards a wall for jogging their front edge, at the end of the stack being formed on a third conveyor belt (40). The invention is applicable to mail preparation.

Description

DEVICE FOR STACKING FLAT OBJECTS SUCH AS POSTAL FOLD

The present invention relates to a device intended for stacking from a bulk flat objects of substantially rectangular shape, such as postal envelopes.

The invention has more particularly been developed within the framework of the processing of mail, precisely in the first phase of organization of this mail following the collection in postal mailboxes.

This first phase of mail organization consists in segregating to separate the envelopes by categories according to different criteria such as their format, the nature of the envelopes, etc., then, at least for some of the categories, arranging them in battery. This is particularly the case with the folds which are intended to be subsequently treated in automatic lines, and which are clearly in the majority. The transfer on these automatic lines requires that the folds are correctly positioned, resting on their large edge and jigged all on the same side.

Currently, this first task of organizing mail after collection is done manually, from the contents of the collection bags emptied in bulk on a table. During the segregation operation, the folds of each category are loaded into boxes which are used for their transfer for subsequent manual or automatic processing. Given the volumes to be treated, a large workforce is necessary, which poses problems of cost and congestion of premises due to the multiplicity of workstations, to which are added problems of efficiency and arduousness for operators. The present invention proceeds from the search for a global solution to these various problems, that is to say a solution which is economical, of reduced bulk, and which offers operators means enabling them to gain very clearly. in efficiency as well as in working comfort, while being simple and reliable.

In this context, a first object of the invention was to provide a device capable of organizing a bulk of flat objects of rectangular shape to make them come out in a pile, jigged on their lower edge and on one of their sides, in order that they are directly transferable at the input of automatic processing lines, under debit conditions in accordance with their performance. To this end, such a device according to the invention is characterized in that it comprises from upstream to downstream: a first conveyor belt intended to receive said flat objects arranged in bulk; a descent hopper fed by said first conveyor belt and whose internal profile is provided such that flat objects take there by dropping a substantially vertical position; a second inclined conveyor belt rising in the direction of transport, the upstream part of which constitutes the bottom of said descent hopper, and the speed and slope of which are chosen such as flat objects arriving there they rest on one of their largest slices; means arranged laterally opposite, directly downstream of said descent hopper, above said second inclined conveyor belt, to form with it a narrow passage for said flat objects, and to stretch the packages of objects so to create between them an offset of their front edges always in the same direction as in a clapboard construction; a passage between rollers constituted by rollers facing each other to project one by one at the outlet flat objects with their large horizontal sections and with a transverse inclination corresponding to a tilt angle of stack, and directed towards a wall of jogging of their front edge, at the end of the stack being formed on a third conveyor belt disposed orthogonally and advancing as the stack is formed. Other characteristics relate to preferred embodiments of this device.

According to one of these characteristics, the rollers of said passage between rollers are arranged so as to twist said flat objects transversely so as to give them at exit said transverse inclination corresponding to a stack inclination angle.

According to another of these characteristics, said lateral means arranged opposite each other above said second inclined conveyor belt are endless bands running at different speeds, the speed difference being chosen so as to accelerate by compared to the others, the objects lying on the downstream side of said third stack advancement mat.

According to another of these characteristics, a transition passage is provided between said inclined conveyor belt and said passage between rollers, the bottom of which is horizontal and where the objects are slowed down so that their large support edge dynamically assume a horizontal position. Said transition passage may include a horizontal base conveyor belt, one side constituted by a fixed vertical wall, and the opposite side constituted by an endless band to perfect the stretching function of the packages performed along said inclined conveyor. In addition, a flexible retaining finger is advantageously mounted on said fixed vertical wall, projecting into the transition passage while pointing obliquely downstream. Of course, the speed differential between the sides is in the same direction along the inclined belt and along said transition passage. Still for the same purpose, in said roller track, only the rollers on the side corresponding to the acceleration side on the inclined conveyor belt are motors. Another object of the invention, in the application to mail, was to create a set of mail preparation from a bulk directly from the collection of mailboxes and, for this purpose, a device such as defined above is further characterized in that it comprises in an upstream section, in association with said conveyor belt one or more segregation stations for flat objects constituting the bulk to be treated.

According to characteristics relating to preferred embodiments of this upstream section of the device according to the invention: each segregation station may include a work plan consisting of a fourth conveyor belt, placed above said first inlet conveyor belt for discharging on it, and whose supply of flat objects and scrolling are controlled by the operator; said fourth conveyor belt can be supplied with flat objects from a fifth conveyor belt with cleats constituting the bottom of a bulk storage hopper. The features and advantages of the invention mentioned above, as well as others, will appear more clearly in the following description and the accompanying drawings, in which: FIG. 1 is a schematic perspective overview of a device according to the invention, intended for a postal application and comprising a first section with a mail segregation station, and a second stacking section; Fig. 2 is the same overall view as FIG. 1 of the same device provided with two mail segregation stations; Fig. 3 is a view in which partially appears from behind the segregation station of the device of FIG. 1, and at the end the stacking section; Fig. 4 is a view from the outside and from the side of the stacking section of the device of FIG. 1; Fig. 5 schematically shows from the outside and in perspective, in the assembled state, the main elements of the stacking section; Fig. 6 shows from the same angle as FIG. 5 a horizontal section at the top of the stacking section, which is located immediately upstream of the terminal part thereof; Fig. 7 is a top plan view of this same section; Figs. 8 and 9 show respectively from the same angle as Figs. 5 and 6 and at an opposite angle, the terminal part of the stacking section; and Fig. 10 is a top view of the terminal part of FIGS. 8 and 9.

First considering Figs. 1 and 2, they represent two versions, respectively with one and two P workstations, of the same device according to the invention, such that it can be used to process a bulk of mail directly from the collection of mailboxes letters. It includes an upstream section A in which a segregation of the folds into at least two categories is manually operated, one of which is clearly predominant in volume and contains the so-called "mechanizable" folds because they will then be processed on automatic lines. After segregation, the folds of this category pass into the second section B of the device where they are stacked automatically.

Section A comprises a conveyor belt 10 continuously scrolling and receiving the mechanizable folds from a work station P. It may alternatively be common to two workstations P as illustrated in FIG. 2, or more.

Each work station P is intended for an operator having in front of him a work plan, which consists of a short conveyor belt 11 placed superimposed above the conveyor belt 10, and advancing in the same direction under the control of the operator.

The conveyor belt 11 is fed in its upstream part by a downspout or slide 12 receiving the folds of a bulk storage hopper 13. The hopper 13 is formed around the upstream part of an inclined cleat conveyor 14 which constitutes the bottom and raises the folds up to the entrance of the chute 12. Its inclination allows a stretch in layer of the bulk batch deposited in the hopper. The advance of the cleat conveyor 14 is also controlled by the operator. The latter therefore has the possibility of completely controlling the flow of the folds moving past it, advantageously by means of two pedals, and it can also control the filling state of the hopper 13 by means of a rear-view mirror 18 mounted on a gantry at the downstream end of the cleat conveyor 14. In addition, it just has to extract from the flow the non-mechanisable plies, and put them in one or more boxes or trays judiciously placed. Fig. 1 thus shows an example of a tray 15 placed at the front of the work surface on a roller conveyor 16 leading to the outside of the device, and a box 17 placed on a fixed support on the side. Mechanizable folds are transferred to the conveyor belt 10 as the carpet 11 advances. Packets of folds that are too high on the carpet 10 are advantageously clipped, that is to say spread out, by identified means. 19 and more clearly visible in FIGS. 2 and 3. As shown, the latter consist of a transverse row of flexible straps suspended in a hammock above the carpet 10, and the low points of which are offset longitudinally. The conveyor 10 brings the mechanizable folds into the entry of the stacking section B, which entry consists of a descent hopper 20. As can be seen in FIG. 3, the hopper 20 has a V-shaped profile in the longitudinal direction of the carpet 10, in other words it narrows downwards due to an inclination given to its wall adjacent to the carpet 10, so that the folds which fall to the inside straighten to the vertical position to rest on the bottom standing on a slice or one of their corners.

The bottom of the hopper 20 is constituted by the upstream part 21a, FIG. 5, a conveyor belt 21 disposed perpendicular to the belt 10, and inclined upward in its direction of transport. The belt 21 scrolls continuously at a speed v1, and this parameter as well as its angle of inclination are chosen so as to create a dynamic effect forcing the folds to take position on it by pressing on one of their large edges. As an indication, the angle of inclination with respect to the horizontal may be of the order of 30 °, and the speed v1 of the order of 1.3 m / s. The conveyor belt 21 on the other hand forms part, immediately downstream of the hopper 20, of a path V for routing the plies to a pile forming station on the upstream end of an outlet conveyor belt 40 disposed orthogonally, Figs. 1 and 2, and which advances as the stack p progresses, from a first ply applied to the inclined plane of a shoe 50 whose inclination corresponds substantially to the desired obliquity of the stack. The output conveyor is therefore parallel to the conveyor 10, and as shown, it is advantageously oriented in return relative to it, to limit the bulk.

Along the belt 21, said track V laterally comprises two endless bands facing each other, respectively 22 and 23, FIG. 5, placed inside the edges of the mat 20 to which, on the other hand, is advantageously given a trough profile by lateral support rollers 24.

The two bands 22, 23 define a narrowing passage downstream from the fact that they approach until they come into elastic contact along the end portion of the outer band 23, beyond which the extension is slightly inner strip 22. This passage between the strips 22 and 23 on the carpet 21 has the function of stretching the overlapping folds of folds to offset the front edges thereof always in the same direction, that is to say as in a clapboard construction. More precisely, between two overlapping folds, the aim is that the front edge of the one which is most towards the original end of the stack p in formation, in other words downstream of the conveyor belt 40 (and in the example shown, closest to the inner strip 22) arrives first at the stack forming station. To this end, the inner strip 22 runs at a speed v2 higher, for example double, at the speed v3 of the outer strip 23, v3 being able to be equal to vl.

Beyond the carpet 21, said track V extends into a transition passage in the form of a horizontal section comprising a base carpet 25, bordered internally by an endless band 26 and externally by a fixed wall 27. The carpet 25 and the strip 26 travel at a speed v4 substantially lower than the speed v1 of the belt 21, v4 being for example equal to 2vl / 3. During the transfer, the folds are suddenly slowed down, which forces them dynamically to take the horizontal position on their support edge.

We see in Figs. 6 and 7 that in the downstream part of said horizontal section, a flexible finger 28 is mounted in the side plate 27 to project into the passage of the folds, pointing obliquely downstream. The function of the finger 28 is to continue the stretching of the packets of superimposed folds started along the conveyor 21, and above all to perfect the offset of the front edges according to a twisted arrangement, retaining the folds lying transversely outwards.

Figs. 8 to 10 represent the terminal part of said channel V, including the pile-forming station, but without the output mat 40 which constitutes its basic surface. This terminal part consists of a passage between rollers where the folds are pulled out of the horizontal section described above, at a speed v5 greater than v3, for example substantially equal to vl. The rollers are arranged in four successive pairs, respectively 30a, b, 31a, b, 32a, b, and 33a, b, and in each pair, they are applied elastically against each other, the rollers 30b, 31b, 32b and 33b being mounted at the end of the pivoting arm against a return spring. On the other hand, only the rollers 30a, 31a, 32a and 33a arranged inwards are positively driven in rotation, always with the same aim of promoting the advance of the folds being most inwardly. According to an important characteristic of the invention, during their passage between the rollers, the folds will be subjected to a twist in order to bring them from the substantially vertical position to a precise angle of inclination corresponding to a chosen stack angle and defined by the inclination of the support plane of the shoe 50. To this end, the axes of the rollers 30a and 30b of the upstream torque are vertical, those of the following torque 31a, b have an intermediate transverse inclination towards the inside, and the two other pairs 32a, b and 33a, b, the same transverse inclination towards the interior more pronounced corresponding to the stack angle. Preferably and as shown, the rollers 30a, 31a and 32a are rotated by an endless band 37 passing over their periphery, and on which the folds will therefore apply during their twisting. The roller 33a is then advantageously driven by the roller 32a, by means of a belt 38 disposed on one of their sides.

The folds are projected, thus inclined but with their large horizontal edges, by the last pair of rollers 33a, 33b. To this end, the drive roller 33a of this torque preferably has a peripheral speed v6 greater than that v5 of the other upstream rollers, v6 being for example of the order of 1.3 v5. In addition, and according to another advantageous characteristic of the invention, the rollers 33a and 33b have complementary profiles at the periphery intended to give a transverse curve to the folds, so that they are stiffened longitudinally when they are released. As shown, the roller 33b thus has two flanges projecting radially from each side of its peripheral surface on which the roller 33a rests.

The folds are released by the rollers 33a and 33b at the stack forming station, that is to say just above the upstream end portion of the output belt 40 (not shown in Figs. 8 to 10) , and in the direction of a lateral jogging plate 41 which stops them. Preferably, the projection of the folds by the rollers 33a and 33b is slightly oblique upstream of the output conveyor 40, so as to cause their front edges to meet a bottom obstacle, such as the support arm 34 of the roller 33b in the example of the drawings, which will guide them to the jogging plate 41. To do this, the line of passage between the rollers obliquely slightly upstream of the output belt 40 from the penultimate pair of rollers 32a and 32b. Note further that the carpet 40 preferably has a slight slope, for example of the order of 5 °, descending towards the jogging plate 41. After they have been released and they have encountered the jogging wall 41, the folds fall in turn just behind the previous fold already in place in the stack p in formation, resting on the output belt by their large lower edge. In doing so, the latter is received in a turn of a helical element of pigtail type 35, driven in rotation by a motor 36 and more clearly visible in FIGS. 9 and 10, which will position it precisely at the foot of the stack p, which is advanced as it is formed by the output conveyor 40, the scrolling of which is controlled by a cell, not shown, detecting the position of each last fold come.

Claims

1) Device for stacking flat objects from a bulk, characterized in that it comprises from upstream to downstream: a first conveyor belt (10) intended to receive said flat objects arranged in bulk; a descent hopper (20) fed by said first conveyor belt (10) and whose internal profile is provided such that flat objects take there by dropping a substantially vertical position; a second inclined conveyor belt (21) rising in the direction of transport, the upstream part (21a) of which constitutes the bottom of said descent hopper (20), and the speed and slope of which are chosen such as flat objects arriving 'place there in support of one of their largest slices; means arranged laterally opposite, directly downstream of said descent hopper (20), above said second inclined conveyor belt (21), to form with it a narrow passage for said flat objects, and to stretch bundles of objects in order to create an offset between their front edges always in the same direction as in a clapboard construction; a passage between rollers constituted by facing rollers (30a, 30b, 31a, 31b, 32a, 32b, 33a, 33b) to project one by one out the flat objects with their large horizontal sections and with an inclination transverse corresponding to a stack tilt angle, and directed towards a wall (41) jogging their front edge, at the end of the stack being formed on a third conveyor belt (40) arranged orthogonally and advancing as the stack is formed. 2) Device according to claim 1, characterized in that the rollers (30a to 33a; 30b to 33b) of said passage between rollers are arranged so as to twist said flat objects transversely so as to give them at exit said transverse inclination corresponding to an angle tilt angle.

3) Device according to claim 1 or 2, characterized in that said lateral means arranged facing each other above said second inclined conveyor belt (21) are endless bands (22, 23) traveling at different speeds , the difference in speed being chosen so as to accelerate with respect to the others the objects lying on the side facing downstream of said third stack advancement mat (40). 4) Device according to claim 3, characterized in that in said passage between rollers, only the rollers (30a to 33a) on the side corresponding to the acceleration side on said inclined conveyor belt (21) are motors. 5) Device according to one of claims 1 to 4, characterized in that a transition passage is provided between said inclined conveyor belt (21) and said passage between rollers, the bottom of which is horizontal and where the objects are slowed down to that their large support edge dynamically assume a horizontal position. 6) Device according to claim 5, characterized in that said transition passage comprises a horizontal base conveyor belt (25), one side formed by a fixed vertical wall (27), and the side facing formed by an endless belt (26) for perfecting the stretching function of the packages performed along said inclined conveyor belt (21).

7) Device according to claim 6, characterized in that a flexible retaining finger (28) is mounted on said fixed vertical wall (27), projecting into said transition passage pointing obliquely downstream.

8) Device according to one of claims 1 to 7, characterized in that it further comprises in an upstream section (A), in association with said input conveyor belt (10), one or more stations (P) of segregation of flat objects constituting the bulk to be treated. 9) Device according to claim 8, characterized in that each segregation station (P) comprises a work surface consisting of a fourth conveyor belt (11), placed above said first input conveyor belt (10) for discharging on it, and whose supply of flat objects and scrolling are controlled by the operator.

10) Device according to claim 9, characterized in that said fourth conveyor belt (11) is supplied with flat objects from a fifth conveyor belt with cleats (14) constituting the bottom of a bulk storage hopper (13).