EP0666234B1 - Piling, separation and evacuation station for batches of flat articles delivered from a processing unit - Google Patents

Abstract

The station consists of a feeder (22,24) for the sheet material panels (20), delivering them to a stop (30) so that they drop onto a stack being formed on an elevator table (60) which moves down as the stack grows, separator arms (70) connected to a cross-member (79) and an output conveyor (90,94). The station is equipped with front and rear temporary supports (45,40) for the panels, situated in a plane more or less parallel to the table (60) and on a level with the lower edge of stop (30). The drive for the separator arm cross-member (79) consists of a drive chain or belt (73) at each end of the cross-member, passing being the front stop (30) and round pulleys (74,77).

Description

The present invention relates to a station for stacking, separating and evacuating batches comprising a predetermined number of stacked plate elements, such as sheets of paper or cardboard, or flattened cardboard boxes, said station being located downstream of a counting and feeding station of said elements leaving a processing machine.

In the counting and feeding station, the sheets are advanced successively along a distributor conveyor in front of a counting device, including for example a photoelectric cell, to the stacking station comprising a collecting device, such as a hopper, in which the leaves are staked in a regular pile. Some form of mechanism is required to adapt the growing stack to the collector. A known mechanism allows the conveyor to be lifted in close connection with the growing pile, while the most typical mechanism known as "free fall" forces the leaves to land on a table with alternating vertical movement which descends at the speed of stack growth. Once the number of sheets corresponding to a batch has been reached, the problem arises of the correct evacuation of this batch without interrupting the machine.

The stacking station of this type described in document FR 2 348 882 comprises a plurality of parallel L-shaped fingers forming a separator normally arranged horizontally and mounted in rotation at one of its ends on a mobile carriage, this separator being designed to temporarily accommodate sheets falling over a previous batch being evacuated by a transporter. The station further comprises a second plurality of parallel T-shaped fingers joined by a rod thus forming a table which can be moved vertically through the conveyor to support the sheets temporarily stacked on the separator and deposit them on the conveyor while the separator withdraws in order to adopt an oblique attitude and returns to the waiting position above the stack being built up on the conveyor. When the next batch is made, the separator collapses to collect the following sheets. However, the maximum number of sheets that can belong to the same batch depends on the maximum lifting angle of the separator, which is necessarily small given the mechanical stresses generated.

The station described in document FR 2 445 563 comprises a hopper closed at the bottom by a vertically movable table and on which squared sheets accumulate. When a predetermined number of sheets is counted, a rear finger is placed on the batch to separate it from the following sheets and descends in combination with the table until it arrives at an evacuation conveyor. A pusher then moves the batch laterally towards the conveyor, the upper sheets being held back by the finger, forward by the batch, while the pusher is withdrawn and the table rises to support these upper sheets. A second finger movable vertically in parallel with the first is already in the waiting position to separate the next batch.
However, the table must necessarily have a surface area smaller than that of the sheets. In addition, this station involves a complex device for displacement in phase opposition of two separating fingers.

In the station described in document FR 2 511 352, the leaves accumulate on a pile supported by a table movable downwards inside a hopper. As soon as a predetermined number of sheets is reached, an interrupt plate or bar advances from the front of the hopper a short distance over the top of the stack. The table supporting the battery continues to move downward relative to the switch so that a vacuum is created in which support arms are inserted. The switch can then be removed and the arms support the accumulation of subsequent leaves. The batch is lowered by the mobile table onto a conveyor belt with evacuation. The empty table then rises and, passing between the support arms, lifts the new stack. The arms can then be removed pending a new cycle. However, the control mechanism of the interruption plate proves to be quite complex in coordination with the movement of the support arms.

The document EP 0 529 708, which reveals the closest state of the art, describes a stacking station provided more particularly for cardboard boxes laid flat at the end of folding and gluing, but some of whose legs are liable to get up. In this station, the sheets brought by the upstream distributor conveyor are launched into the hopper against the front stops, and this by two horizontal and parallel ejector rollers in a vertical rear plane. Leaves fall squarely on top of a pile forming on a table elevator which descends as this stack is created.

When a batch is constituted, a separator located at the front of the hopper, produced in the form of a plurality of forks assembled by a movable cross member along a first vertical rack and a second horizontal rack, comes land on top of the lot to receive the next sheets. The table then descends to the level of an evacuation conveyor on which the batch is transferred by a pusher. The empty table then rises to take charge of the new battery which has already accumulated on the separator having descended as much as necessary. The separator retracts in translation forward, then rises to its standby position at the level of the ejector rollers.

When lowering the table, a secondary set of forks, initially integrated into the first, descends by gravitational force to maintain a slight pressure on the top of the batch before evacuation. In addition, above the evacuation conveyor is permanently installed a second support conveyor applying a light holding pressure on the evacuated batch. However, these pressures used are low and quickly become insufficient as soon as one considers movements accompanied by faster accelerations.

The front stops are mounted together on a horizontal screw allowing their position to be adjusted according to the format of the boxes to be received. However, it quickly becomes apparent that the device for driving the separator along racks can only be of low power, leaving this separator only a passive role of guide. This station then requires the use of a pusher powerful to evacuate the batch of boxes, which always constitutes a slow, heavy and expensive organ present in excess in the station.

Furthermore, a plurality of flexible cams is rotatably mounted on an axis located at the height of the ejector rollers, these cams regularly striking the rear edge of each box to push it towards the stack. However, this device and these coordination means are very complicated for the little effect obtained.

Above all, all the stations described above can only operate to satisfaction for limited rates due to the inertia of the complex mechanisms used: retractable fingers, pushers, etc.

The aims of the present invention is a stacking, separation and evacuation station for batches of stacked plate elements of the "free fall" type like those described above, but which ensure, for high speeds, better reliability of the quality of the batches delivered, in particular by optimizing, even simplifying, the constituent bodies.

• des moyens d'amenée des éléments en plaque contre des butées avant, ces éléments tombant sur le dessus d'une pile se formant sur une table élévatrice descendant au fur et à mesure de la création de la pile, le dessus de cette table étant composé d'un chemin de rouleaux ou de galets ou à bandes sans fin,
• des bras séparateurs reliés à une traverse horizontale porte-séparateurs mobile en translation parallèlement et perpendiculairement au plan de la table, ces séparateurs venant se positionner par l'avant au-dessus d'un lot pour recevoir les éléments en plaque succédant dès que ce lot comprend un nombre prédéterminé d'éléments en plaque,
• un transporteur de sortie au niveau duquel descend la table pour évacuation du lot,
     du fait que cette station comprend plus particulièrement des soutiens temporaires avant et arrière d'éléments en plaque, ces soutiens étant disposés sensiblement dans un plan parallèle à celui de la table et situé au niveau du bord inférieur des butées avant,
     et ce en combinaison avec des moyens d'entraînement de la traverse porte-séparateurs comprenant, à chaque extrémité latérale de la traverse, une chaîne ou une courroie d'entraînement passant à angle droit, en aval de la station et derrière les butées avant, par une poulie d'angle supérieure et une poulie d'angle inférieure, et en amont de la station par une roue de renvoi, l'une au moins des deux roues latérales étant motorisée,
     et en combinaison avec des moyens de guidage de la traverse porte-séparateurs pour maintenir les séparateurs en permanence parallèles au plan de la table.

These aims are achieved in a stacking, separation and evacuation station for batches of plate elements stacked at the output of a machine for transforming such elements, comprising:

• means for feeding plate elements against front stops, these elements falling on top of a pile forming on a lifting table descending as the pile is created, the top of this table being composed an endless track of rollers or rollers or belts,
• separator arms connected to a horizontal transverse separator carrier movable in translation parallel and perpendicular to the plane of the table, these dividers being positioned from the front above a batch to receive the successive plate elements as soon as this batch comprises a predetermined number of plate elements,
• an output conveyor at which the table descends for evacuation of the batch,
  the fact that this station more particularly comprises temporary supports front and rear of plate elements, these supports being arranged substantially in a plane parallel to that of the table and situated at the lower edge of the front stops,
  and this in combination with drive means for the separator carrier cross member comprising, at each lateral end of the cross member, a drive chain or belt passing at right angles, downstream of the station and behind the front stops, by an upper angle pulley and a lower angle pulley, and upstream of the station by a return wheel, at least one of the two lateral wheels being motorized,
  and in combination with means for guiding the separator-carrying cross member to keep the separators permanently parallel to the plane of the table.

In other words, thanks to the reinforcement of the drive mode of the separators, and to the addition of two temporary front and rear supports each animated simply by an actuator, it is possible to use these separators also as means of traction by friction on the top of a batch during its evacuation, and this in replacement of a pusher always too slow. A vertical holding and horizontal force of release on a batch resting on the crazy rollers of the table, which generates a reliable release movement even if very fast.

If the rollers or the rollers or the endless belts composing the path on the top of the table are motorized, or, alternatively, if the roller or endless belt paths composing the path on the table top are crazy but that the table is capable of integrating into a motorized evacuation conveyor located at the start of the exit conveyor, then, by coordination of the upper and lower drive means, a release force of a particularly powerful batch is obtained and balanced which makes it possible to envisage remarkable accelerations, therefore cadences unknown to date.

Advantageously, the means for guiding the cross-member-separator comprise at least one first carriage integral with the cross-member and movable in sliding along a first axis of movement parallel or perpendicular to the plane of the table, this first axis being integral with a second mobile carriage sliding along a second axis of movement perpendicular to the first axis. By correctly dimensioning this arrangement, and, in particular, by providing ball paths in the carriages to reduce the sliding forces, powerful guiding means are obtained which simultaneously have low inertia.

Advantageously, the lifting table as well as the separators and the outlet conveyor are inclined towards the rear by an angle of between 5 and 15 degrees and preferably of the order of 10 degrees. Indeed, thanks to the powerful means used for the evacuation of a lot, we can afford an angle rear improving the jogging of the stack against the rear stop.

Advantageously, the temporary front supports include a plurality of parallel fingers, each advanced or retracted directly by its actuator. Similarly, the rear temporary supports include a movable plate tilting about a horizontal axis and a rear leg of which is connected to an actuator. Thus, these supports are inexpensive to produce, but, thanks to the simplicity of their design, prove to be very dynamic and able to hold a high pace.

Usefully, the station further comprises one or more hanging pressers, mobile in rotation, with a transverse axis carried at each end by supports, this or these pressers pressing on the last plate element coming then resting on top of the battery. Such a relatively simple device ensures rapid positioning of each element on the stack where it is held to avoid any rebound or other parasitic movement.

Preferably, the angle pulleys and the deflection wheel of the drive means of the separator-carrying cross member belonging to the same side are respectively mounted on two identical longitudinal plates and held parallel to one another by cross members, the position of these plates that can be simultaneously modified along a side member of the station frame to easily take into account the format of the sheets or boxes of each production series.

• la figure 1 est une vue schématique en coupe longitudinale de la station selon l'invention,
• les figures 2 a, b et c sont des vues schématiques en coupes transversales de la station respectivement selon les plans supérieurs IIa, IIb et IIc de la figure 1,
• les figures 3 a et b sont des vues schématiques en coupes transversales de la station respectivement selon les plans inférieurs IIIa et IIIb de la figure 1, et
• les figures 4 a-f illustrent schématiquement six phases successives d'un cycle de la station.

The invention will be better understood from the study of an embodiment taken from a non-limiting example and illustrated by the appended figures in which:

• FIG. 1 is a schematic view in longitudinal section of the station according to the invention,
• FIGS. 2 a, b and c are schematic cross-section views of the station respectively along the upper planes IIa, IIb and IIc of FIG. 1,
• FIGS. 3 a and b are schematic cross-section views of the station respectively along the lower planes IIIa and IIIb of FIG. 1, and
• Figures 4 af schematically illustrate six successive phases of a station cycle.

As illustrated in FIGS. 1, 2 and 3, the station according to the invention firstly comprises a frame formed by a pair of rear lateral uprights 12 and a pair of front lateral uprights 14, these uprights being connected by upper side rails 16. Plate elements 20, arriving upstream of a counting and supply station not shown, pass through a pair of ejector rollers 22, 24 arranged on the rear uprights 12. These plate elements are stack on a table 60 to form lots 21 subsequently evacuated, downstream, on an outlet conveyor 94. In other words, the rear uprights 12 are located upstream relative to the direction of movement of the production, and on the right side of Figure 1; while the front uprights 14 are located downstream, that is to say on the left-hand side of FIG. 1.

Opposite the ejector rollers 22, 24 are disposed front stops 30, also visible in FIG. 2b, in the form of substantially vertical plates fixed to the same beam 36. This beam is hung on either side to the side members 16 by means of carriages 35 sliding on rails 18 of the longitudinal members thus allowing a depth adjustment of the position of these stops according to the length of the plate elements 20.

These elements are simultaneously pushed downwards by pressers 80 which, as best seen in FIG. 2a, are hung movable in rotation on a horizontal axis held on either side by supports 82. As before, these supports 82 are connected to the side members 16 by carriages 84 sliding in the rail 18 also allowing a depth adjustment of their position.

In their fall, these elements 20 are squared at the front by the stops 30, at the rear by a stop 32 and from the side by lateral stops 34, these last two members being better visible in FIG. 3a. In particular the lateral position of the stops 34 can be adjusted by action on adjusting screws 31. The elements 20 thus accumulate in a very regular stack on the table 60. This table descends as the increase in pile so that the drop height of the following elements remains substantially constant.

As best seen in FIGS. 1 and 2c, the station comprises a device for separating lots 21 of elements stacked in predetermined number in the form of a plurality of separators 70 connected at their front end to a single horizontal cross member 79 separators. These separators are in the form of bars flattened in the vertical direction and having, in horizontal section, a slightly conical shape oriented towards the rear.
More particularly according to the invention, the cross-member 79 separator carrier is driven at each end by a chain or belt 73 defining its movement path. In addition, the cross member 79 is integral of one or more carriages 76 movable in sliding along a first substantially vertical displacement axis 71, this axis being itself integral with a horizontal carriage 72 mobile, also in sliding, along a second axis of substantially horizontal movement 19. Thus guided, the separators 70 remain constantly parallel to the plane of the table 60.

As best seen in FIG. 1, the chain 73 causes the separation member to traverse a vertical translation behind the stops 30, then a lower translation forward followed by an upward return around a deflection wheel 74 finished by an upper rearward translation, before reaching a waiting position at an upper angle wheel 77. As best seen in FIG. 2c, the upper and lower angle wheels 77 as well as the reference 74 are mounted, on each side of the station, on a longitudinal plate 78, these two side plates being interconnected by several crosspieces 15, 15 '. The plates are themselves connected to the spar 16 through carriages 17 capable of sliding along the same rail 18 in order to allow the depth position of the separators to be adjusted as a function of the format of the plate elements. In parallel, the horizontal movement axis or axes 19 of the carriage 72 are held between two upper crosspieces 15.

The output pulley of a motor 86 mounted between the plates 78 is connected by a chain or drive belt 87 to an external pulley 89 secured to a transmission shaft 88 carrying, opposite each of the idler wheels 74, a drive pulley 89 '. These idler wheels 74 can thus be driven by chains or belts drive 75. The drive separators 70 is thus both powerful and balanced on each side.

Furthermore, the lifting table 60 is capable of descending to the level of an output conveyor 94 of the lots constituted 21. This output conveyor 94 begins, upstream, by a motorized evacuation conveyor 90 which, if desired, can be in the form of a conveyor belt 90 'in the middle of which can descend the lifting table 60 then composed of a plurality of roller tracks.

An upper roller ramp 92 is disposed above the outlet conveyor 94 and applies a pressing force on the top of the lots 21. This ramp 92 is connected at its rear end to the lower part of the front stops 30, such that 'illustrated in Figure 3b, and in its front part to a crosspiece of the frame better visible in Figure 1.

In addition, the station includes a plurality of temporary supports 45 in the form of fingers, each advanced or retracted directly by an actuator 46 arranged in their forward extension. Opposite, and inside a same plane parallel to the table 60, are arranged rear temporary supports 40 on the rear uprights 12. As best visible in FIG. 3a, this temporary support 40 is presented in the form of a plate mounted in rotation about an axis 41 so that it can be tilted forward under the action of an actuator 42 illustrated in Figure 1 and connected to a rear leg of the plate 40.

The operation of the station described above will now be explained in the light of FIGS. 4.

Figure 4a illustrates the station when starting the stacking of a first batch. The separators 70 are then in the high standby position while the elements 20, launched by the rollers 22 and 24 against the front stops 30, fall on a pile forming on the table 60 initially in the high position.

FIG. 4b illustrates the moment when the separators 70 are lowered on the top of the stack at the moment when a batch is counted down, and this in order to receive the following elements. The separator 70 and the table 60 then descend simultaneously, the separator applying a holding pressure on the batch formed.

FIG. 4c illustrates how the separators 70 are found at the lower end of the front stops 30, that is to say at the level of the temporary supports before 45, when the table 60 has arrived at the motorized evacuation conveyor 90 Due to the conical shape given to the horizontal section of these dividers, a free space is created between the batch and the following elements, space in which the supports can advance without effort 45.

FIG. 4d illustrates the major effect of the invention, namely that the batch can be pulled by the separators 70 acting horizontally on top of the batch thanks to the friction forces resulting from the vertical pressure applied. Preferably, the motorized conveyor 90 comes into action simultaneously, thereby enabling particularly rapid and balanced evacuation. From the start of the movement of this lot, and while it still supports the upper sheets, the rear temporary support 40 switches to a horizontal position, its upper elements then being entirely isolated.

FIG. 4e illustrates how, when leaving the batch, the empty table immediately rises towards the new stack being formed, while the separators 70 pass from bottom to top around the idler wheel and then carry out their upper translation.

FIG. 4f shows how the front 45 and rear 40 supports could have been retracted as soon as the table 60 took charge of the new stack, this table then recommencing its descent as the accumulation progresses.

In the meantime, the separators 70 have reached their upper waiting position, ready to fall as soon as the next batch is finally formed.

As we have seen on reading this presentation, the batch once constituted is systematically held firmly below and above by organs during its evacuation, which can thus be carried out very quickly even if this movement involves brutal accelerations.

Because of the power of the organs involved during the evacuation of the lots, we can afford to orient the station slightly obliquely backwards as illustrated in Figure 1, which particularly improves the jogging of the Battery. Many improvements can be made to this station within the scope of the claims.

Claims (9)

1. Station for piling, separating and ejecting batches of plate-like workpieces piled at the outlet of a machine that processes such workpieces, including:

   - means for carrying (22, 24) plate-like workpieces (20) against front stops (30), these workpieces dropping onto the top of a pile growing on a lifting table (60) which moves downwards as the pile grows, the top of this table consisting of a track of rolls or rollers (61) or endless belts.

   - separating arms (70) connected to a horizontal separator-carrying crossbar (79) movable in translation parallelly and perpendicularly to the plane of the table (60), these separators reaching their position from the front over the top of a batch (21) in order to receive the next plate-like workpieces as soon as this batch includes a predetermined number of plate-like workpieces,

   - an outlet carrier (90, 94), at the level to which the table gets down for the ejection of the batch,
      characterized by the fact that this station includes temporary front (45) and rear (40) holders for the plate-like workpieces, these holders being arranged almost in the plane parallel to that of the table and located at the level of the lower edge of the front stops (30),
      by the fact that the means for driving the separator-carrying crossbar (79) include at both lateral ends of the crossbar, a chain or a driving belt (73) passing at right angle downstream the station and behind the front stops (30) round an upper angle pulley and a lower angle pulley (77), and upstream the station round a return wheel (74), at least one of the two lateral wheels being motorized,
      and by the fact that this station includes means (19, 71, 72, 76) for guiding the separator-carrying crossbar (79) in order to maintain the separators permanantly parallel to the plane of the table.
2. Station according to claim 1, characterized by the fact that the rolls or rollers or endless belts making the way above the table are motorized.
3. Station according to claim 1, characterized by the fact that the track of rollers or of endless belts making up the way above the table are free, and by the fact that the table is adapted to be integrated in a motorized ejecting carrier (90) located at the beginning of the outlet carrier (94).
4. Station according to claim 1, characterized by the fact that the guiding means of the separator-carrying crossbar (79) include at least a first carriage (76) being part of the crossbar and slideable along a first shifting axle (71) which is parallel or perpendicular to the table plane, this first axle being part of a second carriage (72) slideable along a second shifting axle (19) which is perpendicular to the first axle.
5. Station according to claim 1, characterized by the fact that the lifting table (60) as well as the separators (70) are slanted rearwards at an angle of between 5 and 15 degrees.
6. Station according to claim 1, characterized by the fact that the temporary front holders include a plurality of parallel fingers (45), each being advanced or retracted directly by its actuator (46).
7. Station according to claim 1, characterized by the fact that the rear temporary holders include a plate (40) which is tiltable around a horizontal axle (41) and having one rear cramp connected to an actuator (42).
8. Station according to claim 1, characterized by the fact that it includes among other items one or several pressors (80), hung rotatable on a crosswise axle carried at each end by supports (82), this or these pressors pushing onto the last coming plate-like workpiece and resting then on the top of the pile.
9. Station according to claim 1, characterized by the fact that the angle pulleys (77) and the return wheel (74) of the means for driving the separator-carrying crossbar (79) located on the same side are respectively arranged on two identical lengthwise plates (78) and held parallel between them by crossbars (15), the position of these plates being simultaneously changeable along a lengthwise beam (16) of the station frame.

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