EP1918235A2

EP1918235A2 - Method and machine for folded concertina stacking of cards made into a strip

Info

Publication number: EP1918235A2
Application number: EP07021088A
Authority: EP
Inventors: Valter Tinivella
Original assignee: Ilapak International SA
Current assignee: Ilapak International SA
Priority date: 2006-11-02
Filing date: 2007-10-29
Publication date: 2008-05-07
Also published as: ITMI20062103A1; EP1918235A3

Abstract

A machine for folded stacking of cards made into a strip comprises a stacking station (13) to which a supplying conveyor (11) sends the strip of cards to be folded concertina-fashion. The stacking station (13) comprises at least a first plane (19) that is tilted upwards in the supplying direction of the strip and is vertically movable downwards to constitute a receiver that receives the strip of cards that folds thereupon to form a stack of cards. Above the tilted plane (19) there is arranged first blowing means (26) blowing downwards. A control unit (30) controls the advance of the strip and drives the blowing means (26) intermittently in a manner synchronised with the advance of the strip to cause the strip to fold towards the tilted plane (19).

Description

The present invention refers to a method and to an innovative machine for the "concertina" stacking of badges or cards made into a strip.
In the prior art various machines have been proposed in which a continuous strip of badges or cards is folded in a concertina manner to stack the cards. Usually, such known machines comprise a horizontal conveyor for supplying the strip of cards to a folding station provided with a tilted plane or with a trapdoor in such a way that the strip of cards falls downwards at the end of the conveyor, acquiring a "fall" speed that causes dragging and folding in a concertina manner in a natural and, therefore, substantially uncontrolled manner. In order to facilitate a rapid fall a continuous air jet can be provided to push the entire strip downwards as the strip reaches the end of the conveyor. A temporary tilted air jet can assist the folding of the first card.
In such machines, as refolding occurs substantially by free-fall, even slight variations in the supplying speed of the strip can easily produce jams or defective folding. Further, correct refolding is closely linked to the weight, thickness and flexibility features of the cards constituting the strip and the thickness features of the film with which said cards are packaged. This makes setting the machine very difficult and makes a reliable increase in packaging speed substantially impossible. Cards may be made of different materials that vary from card to PVC, with thicknesses that are variable from 0.2 to 0.8 mm, whether accompanied or not by a leaflet made of paper that may have from 2 to 8 folds. Weight, thickness and stiffness are thus extremely variable.
With a natural layering of the strip, the combination between the weight and the force of the continuous upper jet constitutes a fundamental critical factor. Stacking speed is always unknown and stacking light and flexible cards, which may be enclosed in a thin film, constitutes a drawback (it is easier to stack heavy and stiff cards: the continuous upper jet constitutes an attempt to make the cards "heavier"). This means that in known machines it is normally necessary to use films of a certain thickness (35 micron) to stiffen the package as much as possible.
The general object of the present invention is to overcome the aforesaid drawbacks by providing a method and a machine for performing the guided refolding of the strip of cards, enabling operation to be substantially independent from the physical features of the strip and enabling operating speed to vary widely.
In view of this object, it was decided to make, according to the invention, a machine for folded stacking of cards packaged into a strip comprising a stacking station to which a supplying conveyor sends the strip of cards, characterised in that the stacking station comprises at least a first plane that is tilted upwards in the supplying direction of the strip and that is vertically movable downwards to constitute a receiver that receives the strip of cards that is folded thereupon to form a stack of cards, above the tilted plane there being arranged first blowing means blowing means blowing downwards, a control unit controlling the advance of the strip and driving at intervals the blowing means in a manner synchronised with the advance of the strip to cause the strip to fold towards the tilted plane.
Still according to the principles of the invention, a method has been devised for folding and stacking a strip of cards comprising the steps of: checking the advance of the strip of cards; driving a jet from the top onto the strip in preset advance positions to make a splice between the cards fold downwards in a preset folding zone and a preceding card to a tilted plane directed upwards in the advance direction of the strip and which receives the stack of cards; continuing the controlled advance of the strip to produce an upward fold of the subsequent splice between the cards, interrupting the jet when the fold moves upwards and then resuming the movement and making the next splice between the cards move downwards to the preset folding zone and the preceding card to the tilted plane; continuing from the start to the end of the strip.
In order to make clearer the explanation of the innovative principles of the present invention and the advantages thereof compared with the prior art, a possible embodiment thereof will be disclosed below with the help of the enclosed drawings that applies such principles. In the drawings:

figure 1 is a partially raised side schematic view of the stacking machine according to the invention;
figure 2 is a raised side schematic view of the machine in figure 1;
figure 3 is a schematic view of an embodiment of a detail of the machine in figure 1;
figures 4 to 15 show an operating sequence of a first operating mode of the machine;
figure 16 shows schematically the action of air jets on the strip in the machine in figure 1 during the first operating mode;
figures 17 to 24 is an initial operating sequence of a second operating mode of the machine;
figure 25 shows schematically the action of air jets on the strip in the machine in figure 1 during the second operating mode;
figures 26 to 29 show an operating sequence of a third operating mode of the machine.

With reference to the figures, in figure 1 there is shown schematically a machine, indicated generally by 10, made according to the invention. The machine 10 comprises a conveyor 11 that supplies cards 12, packaged in a strip of film, to a stacking station 13 which in turn unloads into an underlying unit or evacuating station 14. The conveyor 11 is served by a card supplying and packaging unit, which is not shown as it is of known type and is easily imaginable by those skilled in the art. Each strip of cards supplied to the station can be formed by a number of cards predefined at will, from example from 5 to 100. In general, according to the prior art the strips consist of cards regularly spaced apart and contained in a web of plastic film welded along the four sides of each card. Between the cards 28 transverse folding lines of the strip of film are formed.
The conveyor 11 consists of conveyor belts or lower tracks 15 and upper tracks 16. The lower tracks and upper tracks may be two, coupled parallel in the width of the strip of cards, as is seen schematically in figure 2.
The length of the conveying tracks is such that the lower tracks 15 convey the cards as far as the release point above the stacking station, whilst the upper tracks retain the cards only to approximately a card of distance from the head of the lower tracks. As will become clear below, with this expedient the upper and lower tracks retain and release the cards in such a way that the rear thrust of the advancing strip is able to pitch upwards the film splice between the cards.
As can also be seen well in figure 2, the station 13 comprises rear contrasting means 29 and receiving means 17. Advantageously, the contrasting means 29 defines above a plane 18 tilted downwards in the movement direction of the strip. The tilted plane 18 is substantially tangential to the head roller of the lower track 15.
The receiving means 17 on the other hand defines a tilted plane 19 above directed in the advance direction of the strip, so as to force the cards to ascend again along the plane, as will become clear below.
Between the tilted planes 18 and 19 there is a space or folding point 20. At the upper end of the tilted plane 19 there is a front contrast 21, advantageously sawn with teeth directed downwards, to contain the head of the card when the card is pushed from behind and to avoid the lifting thereof.
The receiving means is driven to move vertically and thus lower the tilted plane 19 as it gradually receives the stacked cards and lastly move the pack of cards as far as the evacuation unit 14 below.
Advantageously, the receiving means consists of pairs of adjacent supporting elements 17a, 17b between which the cards rest. The contrasting means 29 is also advantageously made of a pair of elements or adjacent plates 29a, 29b.
The evacuation unit 14 advantageously comprises a releasing plane 22 and step pushers 23 to move horizontally the pack of cards unloaded onto the releasing plane owing to the vertical movement of the receiving means 17.
In order to enable packs of cards to be received rapidly sequentially, the receiving means 17 comprises a plurality of elements that form tilted planes 19, so that whilst a pack on a tilted plane is unloaded, a subsequent pack is already being formed on another tilted plane, as is clear from figure 1.
Figure 3 shows an advantageous embodiment of the means 17, consisting of two adjacent vertical belts 24, 25, driven to rotate upon command in an opposite direction in a synchronised manner and carrying at intervals respective elements 17a and 17b. In this way, the elements 17a and 17b placed alongside in pairs form a sequence of tilted planes 19 moving downwards to convey the stacks of cards from the upper forming zone to the lower unloading zone on the evacuation unit (not shown for the sake of clarity in figure 3).
As visible in the figures, the stacking station also comprises first means 26 emitting air jets vertically downwards, in the direction of the tilted receiving plane 19, and second blowing means 27 emitting air jets in a direction tilted away from the front zone of the tilted plane 19 towards the front zone of the tilted plane 18.
The means 26 has to hit from above the surface of the card arriving below the aforesaid means 26 with jets distributed over the surface of the aforesaid card. Advantageously, the means 26 has four emitting nozzles arranged according to the corners of a rectangle in such a way that the hit zone does not have a pointed shape but the jets intervene near the receiver, preventing the cards folding in the middle.
An electronic control unit 30 that is per se substantially known and therefore not shown in detail controls in a synchronised manner the various elements of the machine, in particular synchronising the blowing means with the advance of the strip of cards. Known sensors for detecting the position or presence of the cards may possibly be used to monitor the machine.
In figures 4 to 15 sequential steps of a stacking cycle run by the machine are shown schematically.
In particular, in figure 4 there is shown the arrival of the head of the strip, with the first head card that falls onto the tilted plane 19 until the first head touches the tilted plane (figure 5) and is guided thereby upwards until coming to rest completely. Reaching the correct arrest position on the tilted plane can be helped by the front contrast 21 (not shown for the sake of simplicity). In a well-defined advance position of the strip the upper jet is actuated, so as to push the first and the second card onto the folding corner (figure 6). With the movement forwards, the third card can pitch upwards, owing to the fact that the upper tracks 16 end about a card of distance before the lower tracks.
At a given advance point of the strip the tilted plane 19 of the receiver starts to descend at a descent speed that is proportional to the advance speed of the strip (figure 7). This enables the card overturning movement to be kept constant over the entire strip.
At a given advance point of the strip the upper jet stops, so as to enable the splice between the second and the third card to fold naturally upwards, owing to the forward thrust of the strip and to the space of a card between upper and lower tracks (figure 8). The same upwards folding thrust keeps the card already on the tilted plane 19 pressed downwards.
At a new advancing point of the strip, after the upward fold has passed, the upper jet resumes (figure 9) and continues to project towards the folding corner the splice between the third and the fourth card (figure 10). In the meantime the receiver 17 continues to descend.
The process is repeated in the same way until the last card of the strip. At the last card, the upper jet that produced the last downward fold continues in such a way as to project towards the folding corner between the tilted planes the splice between the penultimate and last card (figure 11).
The receiver has continued to descend until this moment or would have been able to stop in a suitable position so as to receive all the cards.
At a well determined advance point of the strip, the upper jet stops, so as to enable the last card to rotate freely around the folding corner (figure 12). The receiver 17 moves rapidly downwards, dragging the last overturned card (figure 13) and, at a set point, the upper jet can possibly resume, so as to help the last card to adhere to the folded strip (figure 14) and then ceases.
In the meantime, the receiver continues the rapid descent until reaching the unloading position, whilst a new receiver reaches the receiving position of the new first card (figure 15). The receiver that moves through the unloading position releases the strip folded on the plane 22 of the evacuating station, from which the strip can be extracted by the step pusher (or another evacuating device located in the station).
At this point, the disclosed cycle can resume from the start with the new strip of cards.
To summarise, in order to fold the splice of film downwards correctly between two cards, it is first necessary to constitute a folding point, which corresponds to the point where the intersection of the backwardly tilted plane 19 with the tilted plane 18 of the rear contrast occurs. In order to create the downward fold, force must be exerted downwards with the upper jet that starts after the preceding upward fold has passed from the jet and that finishes before the subsequent upward fold has again risen towards the jet. The upward fold occurs without the help of the jet, but owing to the thrust that the tracks exert at the back on the card the head of which is lifting the tail of the preceding card.
Let a sequence of cards be considered, be numbered 0,1,2...n, with the card '0' already coming to rest on the receiver with the head inserted in the front saw tooth (which prevents the raising thereof) and the tail in the folding point, where the tail joins the subsequent card (card 1). The tail of the card 1 is high inasmuch as it is lifted by the head of the card 2, the tail of which is held low by the head of the card 3, which cannot lift up because it is pinched between the tracks. The advance of the card 3 is translated as an upward fold of the splice between the tail of the card 1 and the head of the card 2. The jets have to become synchronised with these folding movements to help the cards to be correctly arranged, bearing in mind that if a jet is blown too soon there is a risk of hitting the card 1 at the front that is being forced to fold upwards, pivoting on the folding point. The upward fold between the tail of the card 1 and the head of the card 2 has to pass undamaged in front of the jet and afterwards blowing can be resumed to push the fold downwards (to the folding point) that consists of the splice of the tail of the card 2 with the head of the card 3. The cycle is repeated infinitely, i.e. for as long as there are cards in the strip. The entire strip is thus folded as a concertina.
In figure 16 the air blowing zones are shown schematically as the cards transit in the stacking station. The blowing zone is approximately astride a downward fold.
The machine according to the invention also enables the first card to be overturned. The decision to rotate the first card occurs on the basis of the even or odd number of cards constituting the strip and this is defined on the basis of which face of the last card it is desired should appear from the top of the stack (for reading codes or because it is the "good face" of the card).
The overturning cycle is shown schematically in figures 17 to 24. This cycle is added to the head of the previously disclosed stacking cycle, replacing the receiving steps of the first card (figures 4-7) therewith.
When it is necessary to overturn the first incoming card (figures 17 and 18), the receiver 17 is lowered in such a way as not to interfere with the rotation of the card. The incoming card thus rests only on the tilted plane 18 with the front transverse jet 27 that from a certain advance point of the card starts to push the head of the card to the fold point (figure 18). The front transverse jet continues for a well-defined portion of the strip so that, as the advance of the card proceeds, the oblique jet causes the card to be moved vertically (figure 19).
In a well-defined advance position of the strip (preferably when the card is within the vertical) the receiver starts to ascend again, contributing to the final rotation of the first card (figure 20). The speed at which the receiver ascends is directly proportional to the advance speed of the strip of cards. In a well-defined advance position of the strip the oblique jet ceases in order not to hinder the lowering of the card on the front tilted plane (figure 21).
In a subsequent well defined advance position of the strip the upper jet is activated to blow towards the folding corner between the second and the third card (figure 22).
The receiver, which in the meantime has continued to ascend, moves to the high receiving position (figure 23), substantially at the same point at which the first card of a strip would be received without the initial rotation, whilst the upper nozzle continues to blow, completely pressing the second card against the first. At a well determined advance point of the strip the receiver starts to descend (figure 24) at a descent speed that is proportional to the advance speed of the strip and basically starts (substantially with the steps from figure 7 onwards) the normal refolding cycle disclosed above, as if it were the strip without rotation of the first card.
In figure 25 the blowing zones of the air are shown schematically as the cards transit in the stacking station.
On the head card there is the front oblique jet that folds the card in the opposite way. On the subsequent cards there is the upper jet with the blowing zone that is approximately astride a downward fold between the cards. The position of the blowing nozzles can be adjustable for calibrating the blowing position according to the folding features of the cards, so that the exact position of the blowing zone can vary in the practical application.
As a further advantage, the machine according to the invention can also stack without drawbacks individual (or individually enveloped) cards. In fact, in known machines the single card is affected by the same already mentioned drawbacks. A thick, stiff and heavy card falls more easily and constantly than a light and flexible card and known machines are greatly affected by such variations.
In figures 26 to 29 there is shown schematically the operation of the machine according to the invention during stacking of the single cards. In this case, the cards arrive horizontally at the end of the conveyor (figure 26) to then be pushed onto the receiver by means of the upper jet (figure 27). The jet must hit from above all the cards in such a way that they descend towards the receiver as rapidly and stably as possible. Owing to the four nozzles arranged in such a way that the affected zone is not point-shaped or central, but that the jets intervene near the receivers, the first card of the stack - which does not have other cards underneath - being supported only at the sides, is prevented from folding in the centre, bouncing as if through the effect of a spring. Between one card and the other the upper jet is interrupted (figure 28) in order not to disturb the head of the new card that has to travel as far as the point in which the jets are reactivated.
As the cards are launched one by one into the receiver, the existence of the upper track that is shorter than the lower track is less important. As the rear tilted plane 18 is not necessary, the arresting element 29 can be removed or shaped differently. Similarly, the tilted plane 19 does not need to have the folding zone 20 lowered. The elements 17 can therefore also be temporarily replaced by continuous upper plane elements (as shown in figures 26-29). In the case of a structure as shown in figure 3, two series of belts 24, 25 can be advantageously provided, one carrying the tilted and graduated plane elements of figure 1 and the other the continuous and tilted plane elements of figure 26.
In the case of stacking of single cards, between the cards there must be a minimum space that enables the receiver to pass through the last card of a stack and the first of the subsequent one.
Obviously, the cards arrive one behind the other, so it is the receiver that, by moving downwards after a carefully determined number of cards, enables a stack to be completed and a new one to be commenced (figure 29).
It is now clear how the preset objects have been achieved, providing a method and a machine applying the method, which is relatively simple and enables cards packaged into a strip to be stacked with great efficiency.
With a machine according to the invention it has been found to be possible to stack cards in strips at a speed that is even double that of faster traditional machines, without jamming or folding errors. Further, the constant control of the advance of the cards synchronised with the force exerted from above by the jet, which is activated and deactivated in well-defined advance positions of the strip, makes correct folding substantially independent of the operating speed over a wide speed range. This enables significant production increases and changes to current speeds to adapt the stacking process to momentary speed variations of the treatment units arranged downstream and upstream of the stacking unit. For example, if during formation of the strips a card should be missing, the control system may detect this and delay or accelerate the cards to compact the empty space before the formation of the sealed strip. Owing to the principles of the present invention, such a speed change does not affect the operation of the stacking section.
By controlling the advance of the cards and commanding the folding of the strip through controlled jets as a consequence of the advance, a machine is made the function of which is substantially independent of the weight and the stiffness of the cards and of the weakness of the preincision of the film at the folding points between the cards. Owing to the less critical importance of the adjustments, which is reflected in greater permitted tolerance of the critical factors, production speed and output are significantly increased, machine setting time when changing size is significantly reduced and thinner films can be used (for example even down to 20 micron).
The machine according to the invention, in addition to stacking cards packaged in envelopes with four welds (which have a certain consistency in the folding zone between cards and with the preincision between two successive welds that is the "weak" point of the fold), it can also be used with cards packaged in flowpacks with the traditional three welds of which one is constituted by the lower longitudinal flap, where the zone between paper and welding is significantly weaker than the point where the preincision occurs and which should support the fold.
Naturally, the above description of an embodiment applying the innovative principles of the invention is provided merely by way of non-limiting example of such innovative principles and must not therefore be considered to limit the protective scope of what is claimed herein.
For example, downstream of stacking a known packaging unit may be located that packages each stack of cards in a film enclosure.
The control of the advance of the strip to synchronise therewith blowing and the other operations of the machine can be performed in any known manner, as is easily imaginable by those skilled in the art.

Claims

Machine for folded stacking of cards packaged in a strip comprising a stacking station (13) to which a supplying conveyor (11) sends the strip of cards, characterised in that the stacking station (13) comprises at least a first plane (19) that is tilted upwards in the feed direction of the strip and that is vertically movable downwards to constitute a receiver that receives the strip of cards that folds thereupon to form a stack of cards, above the tilted plane (19) there being arranged first blowing means (26) blowing downwards, a control unit (30) controlling the advance of the strip and driving at intervals the blowing means (26) in a manner synchronised with the advance of the strip to cause the strip to fold towards the tilted plane (19).
Machine according to claim 1, characterised in that the conveyor (11) comprises a lower web (15) and an upper web (16) between which the strip is dragged, the head of the upper web (16) terminating before the head of the lower web (15) by about the length of a card in the extension direction of the strip.
Machine according to claim 1, characterised in that between the conveyor (11) and the first tilted plane (19) there is a second tilted plane (18) that substantially starts from the end of the lower web (15) and is directed downwards in the advance direction of the strip, between the first and second tilted plane forming a downward folding zone (20) for the strip between the cards.
Machine according to claim 1, characterised in that the first tilted plane (19) as it moves downwards unloads the stack of cards at an evacuating station (14) below.
Machine according to claim 1, characterised in that the first tilted plane (19) is defined by a facing pair of tilted plane elements (17) each fixed on a respective belt (24, 25) that is driven to move vertically.
Machine according to claim 5, characterised in that the pairs of tilted plane elements (17) are a plurality of pairs spaced along the respective belts.
Machine according to claim 1, characterised in that at the upper end of the first tilted plane (19) there is a vertical contrasting element (21).
Machine according to claim 7, characterised in that the vertical contrasting element (21) has a downwardly serrated surface for resting the cards in the strip.
Machine according to claim 1, characterised in that before the first tilted plane (19) there is a vertical contrasting element (29).
Machine according to claims 3 and 9, characterised in that the contrasting element (29) terminates above with the second tilted plane.
Machine according to claim 1, characterised in that above the first tilted plane (19) there is second blowing means (27) in a direction tilted away from the front zone of the tilted plane (19) towards the incoming direction of the strip, the control unit (30) controlling the advance of the strip and driving the second blowing means (27) in a manner synchronised with the advance of the strip to cause, when required, the first card of the strip to fold in the opposite direction.
Method for folding and stacking a strip of cards comprising the steps of:
- controlling the advance of the strip of cards;

- activating a jet from above onto the strip in preset advance positions to make a splice between the cards fold downwards in a preset folding zone and a previous card towards a tilted plane directed upwards in the advance direction of the strip and which gathers the stack of cards;

- continuing the controlled advance of the strip to produce an upward fold of the subsequent splice between the cards, interrupting the jet when the fold passes upwards and then resuming the jet and making the subsequent splice between the cards fold downwards to the preset folding zone and making the preceding card fold towards the tilted plane;

- continuing from the start to the end of strip.
Method according to claim 12, in which there is an initial step that comprises producing, in a manner synchronised with the advance of the strip, a jet of air in a direction tilted away from the front zone of the tilted plane towards the incoming direction of the strip to make the first cards of the strip fold in the opposite direction, when desired.
Method according to claim 13, in which the tilted plane is lowered before the jet in a tilted direction and is then lifted up again to complete the opposite folding of the first card.