ITUB20155339A1 - PAPER-SANDING MACHINE WITH CLAMPING DEVICE. - Google Patents

Description

"Cartoning machine with gripper gripping device"

DESCRIPTION

Technical field

The present invention refers to a cartoning machine, that is a machine which places articles such as bottles or other containers in boxes, usually cardboard boxes. In particular, the invention relates to a cartoning machine with a gripper device for gripping, orienting and placing the containers in the box.

Known technique

The packaging of wine bottles, for the most part, is carried out in cartons containing 6 or 12 bottles, which are inserted vertically into the carton box by a cartoning machine. A cartoning machine normally collects the already labeled bottles from the bottling line, arranges them on a multi-row table according to the number to be inserted in the carton, picks them up by means of a gripping head and inserts them vertically into the previously formed, glued carton. , closed at the bottom and open at the top.

A smaller but increasingly significant quantity of quality bottles, first of all Champagne or the great "cru" wines, is packaged in cartons in a horizontal position in one or more layers. This arrangement is dictated by the need to keep the cap in contact with the liquid to maintain its elasticity and therefore its perfect conservation over time.

Traditionally the bottles are arranged horizontally in rows in the cardboard oriented in alternating directions, according to the expression tete-bèche, that is to say placing the cap of a bottle next to the bottom of the adjacent bottle, and so in succession until the row is completed. with a typical alternating sequence A B A B. This offers the opportunity to reduce the volume of the package in the case of Champagne-type bottles that have a conical shape and in general to keep the weight distributed in the carton balanced. Inside the cardboard the various layers of bottles are separated from each other by cardboard separator sheets, normally called "beehive" (partition). These separators, which are also placed on the bottom of the cardboard as well as interposed between the various layers, have interlocking formations to hold the neck and the bottom of each bottle, so as to keep it spaced even from the adjacent bottles in the same layer.

It is customary to alternate the sequence or arrangement of the bottles also in the vertical direction between the various layers, so that each bottle is oriented in the opposite direction to the underlying bottle. Therefore, if in one layer the bottles are arranged according to the sequence A B A B, in the layers immediately above and below the bottles are arranged according to an alternating inverse sequence, i.e. B A B A. For these peculiar characteristics, much of the packaging is carried out manually.

Some of the large companies that produce high quality wines have specialized machines to carry out this type of packaging. These machines can be grouped into two families: horizontal case packers and dedicated robots. Some models of horizontal case packers and robots can only carry out horizontal packaging. Other models of machines, called "combined", are adaptable to carry out both vertical and horizontal packaging.

The cartoning machines make use of gripping devices, called gripping heads, which are mounted on moving parts of the machine and provide for hooking the bottles and depositing them in the carton.

A distinction can be made between machines which perform the work by means of a single handling device and machines which use two separate devices.

According to the solution which makes use of two separate devices, a fixed device on the alignment table provides for the points 2, 3, 5: lifting, alternating rotation and alignment. A gripping head provides for points 4, 6, 7, 8: hooking, transfer, positioning, storage.

1.Alignment of the bottles, vertically oriented, in a row in a picking area.

2. Lifting the bottle above the containment lane and any mechanical stop.

3. Horizontal rotation of the bottle in an alternating direction.

4. Attachment of the bottle by means of a lateral gripping arm provided with a suction cup or a mechanical gripping hand against a fixed stop.

5. Alignment of lying bottles.

6.Transfer of the bottle into the carton

7. Positioning of the bottles according to the size of the containment hive, with the bottles in the same row or layer slightly spaced from each other.

8.Deposited in the carton.

Point 1. is generally carried out by a motorized conveyor equipped with containment guides which provides for the formation and advancement of the row.

This solution is suitable for faster machines, and has the following advantages:

a. rotation is stable as it is performed by a separate non-moving device.

b.rotation and alignment are performed more slowly with the same productivity as they have more time available (the entire bottle transfer cycle).

c. the speed of execution of the movement of the gripping head is greater as the bottle is hooked vertically.

On the other hand,

d. the rotation device is very complex and expensive.

e. the physical arrangement of the rotation sockets cannot be changed and therefore the rotation sequence is fixed.

f. a precise adjustment of the rotation device for the format change according to the bottle diameter, requires complex guides and even more complex actuators expensive in the case of automatic adjustment.

g, the presence of a fixed rotation device excludes the possibility of creating a combined vertical - horizontal version in the same space occupied by the machine.

According to the solution that uses a single device, a gripping head provides points 2, 3, 4, 5, 6, 7, 8, hooking, lifting, rotating, aligning, positioning, depositing,

1.Alignment of the bottles in a row in the picking area.

2. Attaching the bottle with an arm equipped with a lateral suction cup against a fixed stop.

3. Lifting the bottle above the containment lane and any mechanical stop.

4. Horizontal rotation of the bottle in an alternating direction.

5.Alignment of the bottles

6.Transfer of the bottle into the carton

7. Positioning of the bottles according to the containment hive

8.Deposited in the carton.

Point 1. is generally carried out by a motorized conveyor equipped with containment guides which provides for the formation and advancement of the row.

This second solution is suitable for slower machines, and has the advantage of using a single integrated device. On the other hand,

vertical gripping occurs more slowly;

on the alignment device there are fixed stops which serve to hold the bottle steady in position, so that the suction cup arm can engage and withdraw it effectively. These stops must be adjusted from time to time, according to the diameter and height of the bottles;

the alternate positioning of the fixed strikers requires expensive adjustments in the case of self-adjusting adjusters to be disassembled in cases where the machine is of the combined type.

In the case packer machines that adopt this second solution, the alternation of the arrangement of the bottles in the superimposed layers is obtained by applying a scheme A B A A B A. This scheme creates an asymmetry in the sequence which, following the rotation of the gripping head by 180 ° around a vertical axis, allows to obtain an alternation of the arrangement of the bottles according to the scheme B A B B A B in the next overlying layer.

The hives (separators) are arranged in a special hives warehouse of the machine, superimposed on each other in a number of stacks called stations, corresponding to the number of cartons processed and oriented according to the bottle storage scheme. The separator sheets that protect the bottle are asymmetrical and are arranged in the box at the position of the bottle neck; for this reason, the rotation must be applied to both the bottle gripping head and the separator hives gripping head.

This solution has a serious limitation in the overall dimensions due to the rotation of the gripping heads which allows it to be used with a reduced number of bottles (generally six), thus limiting the performance of the machine, except for the use of very large maneuvering spaces and costs. of a robot.

A second limit is found in packages with rows of even number of bottles that must be alternated, for example the 12-bottle case of Champagne in which 3 layers of 4 bottles each are superimposed. In this case, the rotation of the gripping head with an even number of bottles does not generate an inversion of the layer, since the bottles in sequence A B A B rotated by 180 degrees are always in the same position. So either we give up on having sequences in alternate layers, or we intervene manually or we resort to the use of more sophisticated and complex manipulation equipment.

Summary of the invention

An object of the invention is to improve the effectiveness of a cartoning machine. It is desired to eliminate mechanical stops and related adjustments, and to increase the gripping speed and stability of the article when it is picked up and lifted.

Another object of the invention is to provide a flexible cartoning machine, which gives the possibility to freely choose the direction of rotation of the articles. You want to have the possibility of setting the machine via software allowing you to arrange the items in any sequence, without any type of mechanical adjustment.

A further object is to provide a compact cartoning machine, which at the same time allows to withdraw also numerous groups of articles at each single cycle, for example even 12/16/18 bottles at a time.

A further object is to provide a cartoning machine which also allows to alternate the arrangement sequence even for rows of even numbered articles.

These and other objects and advantages, which will be better understood hereinafter, are achieved by a cartoning machine having the characteristics set out in the appended claims.

In summary, the cartoning machine comprises a plurality of gripper gripping means having two movable arms, preferably articulated arms, which cooperate together to grip an article from opposite sides. At least one of the two arms has a rotating grip suction cup. The gripper lifts, one of the two arms disengages from the article, while the other holds it with the suction cup and, making it rotate 90 °, lays the article horizontally to place it in this position in a box open towards the tall. Preferably both articulated arms are equipped with suction cups.

Brief description of the drawings

The functional and structural characteristics of some preferred but non-limiting embodiments of a centering device according to the invention will now be described. Reference is made to the attached drawings, in which:

Figures 1 and 2 are perspective views of a cartoning machine according to an embodiment of the invention;

Figure 3 is an exploded perspective view of some components of the cartoning machine of Figure 1;

Figures 4 and 5 are respectively a front view and a perspective view of some parts of the machine in a first operating phase;

Figure 6 and Figure 7 are front views of a part of the machine in an operating phase thereof subsequent to that of Figure 4;

Figures 8 and 9 are respectively a front view and a perspective view of some parts of the machine in an operating step subsequent to that of Figures 6 and 7;

Figures 10 to 15 are front and perspective views illustrating a sequence of operating steps subsequent to that of Figure 8;

Figure 16 is a side view of a part of the machine in a phase of a machine part in an operating phase thereof subsequent to that of Figure 14;

Figures 17 to 26 are front and perspective views which illustrate a sequence of operating steps subsequent to that of Figure 16;

Figures 27 to 29 are front views which illustrate a sequence of operating steps of a part of the machine according to an alternative embodiment with respect to that of the previous figures; Figure 30 illustrates a case packing machine of the combined type; And

Figure 31 is an exploded perspective view of some components of the cartoning machine of Figure 30.

Detailed description

Referring initially to FIG. 1, a cartoning machine according to an embodiment of the present invention is indicated as a whole by 10. The cartoning machine comprises an inlet station A where a row of articles 11, in this example containers such as bottles, are fed to the machine from a inlet conveyor 12. The bottles arrive at the inlet station in an upright or vertical position, aligned in a row extending in or parallel to a direction of advance x defined here longitudinally. As understood here, terms and expressions indicating orientations such as "longitudinal" and "transverse" are to be interpreted with reference to the longitudinal direction in which the inlet conveyor 12 extends.

Flanked transversely to the inlet station A, the cartoning machine has a loading station B where there is a second outlet conveyor 13 on which a series of boxes S open upwards, typically boxes with a rectangular base, are arranged in a row. Preferably the conveyors 12 and 13 are parallel.

The cartoning machine 10 comprises a transfer apparatus 14 which picks up groups of bottles 11 from the inlet station A and places them, in a lying position and in overlapping rows, in the boxes S in the loading station B.

Side by side with the loading station B, on the opposite side of the inlet station A, a magazine C of partitions can be provided, which comprises a plurality of vertical stacks P of horizontal separator sheets F aligned parallel to the longitudinal direction. The separator sheets are cyclically withdrawn from the stacks and placed in the boxes to separate, in a per se known manner, one each layer or row of bottles lying down from the overlying and underlying layers, and both to retain each bottle slightly spaced from the adjacent bottles in the same layer. . In the example schematically illustrated, the separator sheets are stacked in an initial flattened condition, according to methods known per se.

As will be described later, the transfer apparatus 14 can be adapted to pick up groups of bottles from the inlet station and place them in parallel rows, vertically oriented, in the boxes S, according to the typical operation of a vertical cartoning machine. In this mode of operation, vertical partitions are introduced into the boxes according to a grid pattern that divide the space inside the bin into compartments or cells open upwards, where the bottles are arranged individually.

The transfer apparatus 14 comprises a fixed bridge structure 15 with a horizontal beam 16 extending in a transverse direction over the stations A, B, C. The transfer apparatus 14 further comprises a carriage 17 sliding with reciprocating motion along the beam 16 and a head 18 for gripping the bottles. The head 18 is suspended at the base of a column 19 carried by the trolley 17 and vertically with reciprocating motion with respect to the trolley.

The gripping head 18 comprises a platform 20 (FIG. 3) which includes a series of drives for various gripping and handling members described below, and preferably also comprises a series of couplings 21 for removably connecting the gripping members. and their supports, indicated as a whole with 22 in the lower part of FIG. 3.

The head 18 carries a plurality of gripper devices 23 for gripping and rotating the bottles. The gripper devices 23 are longitudinally side by side in the lower part of the head 18. Each gripper device 23 comprises a pair of arms 24, 25, movable and substantially symmetrical with respect to a longitudinal vertical plane V (FIG. 4).

At least one of the two arms is provided with a terminal suction cup 27, rotatably mounted around a horizontal axis 26, The rotational movements of the suction cup 27 around the axis 44 are carried out by an actuator 45, preferably a pneumatic or electric actuator 28 (FIG. 7).

Each arm 24, 25 is movable between a lowered position, in which it can engage a bottle, and a raised and passive position, in which it is moved away from the suction cup of the other arm so as not to interfere with the bottle, as explained further on.

Preferably each arm 24, 25 is an articulated arm (FIG, 7) which includes an articulated quadrilateral 29 which allows the terminal part of the arm to be raised with a limited lateral or transverse movement away from the other arm. In some of the accompanying drawings (FIGS. 4, 6, 8, 10) parts of the arms and related actuators are not shown.

Each arm 24, 25 is carried by a respective slide 30, 31 transversely sliding along a horizontal transverse bar or guide 32 or, more preferably, two parallel transverse bars placed side by side in the longitudinal direction to prevent the slides and arms from making undesired oscillations in a longitudinal vertical plane. For the same purpose, ie to prevent such oscillations, the guide 32 can have a non-circular cross section. The slides 30, 31 are associated with actuators 33 capable of bringing the two slides of the same gripper device 23 from more distant positions to positions closer to a longitudinal center line of the head.

In the illustrated example, each articulated quadrilateral comprises a rod 34 which has the terminal suction cup, and a pair of levers 35, 36 hinged to the rod 34 and to a support 37 fixed to one of the transverse slides 30, 31. rotation of the levers 35, 36 with respect to the support 37 are carried out by an actuator 39, for example a pneumatic or electric actuator.

The transverse guides 32 have opposite ends mounted in a longitudinally sliding manner along a pair of longitudinally extending parallel bars or guides 40. The transverse guides 32 are associated with actuators and / or transmission members capable of mutually moving the transverse guides 32 away and approaching each other, and therefore bringing the various gripper devices 23 closer and further away from each other in the longitudinal direction.

Preferably, the transverse guides 32 are associated with the attachments 21 which allow their release from the upper part of the head and from the actuator members which move them along the longitudinal guides 40.

An exemplary operating cycle of the cartoning machine is the following. A row of vertically oriented and longitudinally aligned bottles on the first conveyor arrives at the inlet station A (FIGS. 4 and 5). The carriage 17 is carried along the beam above the inlet station A. Initially, the articulated arms of the various gripper devices are in the raised position. The bottles 11 in a row on the inlet conveyor 12 are pushed into contact against each other. The gripper devices 23 are spaced from each other along the longitudinal guides in such a way that each gripper device is aligned in a vertical plane with a respective bottle to be picked up from the inlet conveyor. The two transverse slides 30, 31 of each gripper device can be in the mutually spaced position along the transverse guides. Preferably, the two transverse slides of each gripper device are placed symmetrically with respect to the longitudinal vertical plane V passing through the centers of the row of bottles on the inlet conveyor.

The column 19 is extended downwards to bring the head 18 closer to the bottles to be picked up. Both movable arms of each gripper device are lowered to clamp a bottle between the two suction cups 27 (FIG. 6).

Vacuum is applied to at least one of the two suction cups to lift the bottle from the conveyor. For a more effective grip, in case you want to lift the bottle more quickly, the vacuum can be applied simultaneously to both suction cups of the same gripper, in such a way as to hold the bottle with greater stability to counteract the inertia resulting from a more abrupt vertical acceleration.

Alternatively, the vacuum can be applied to only one of the suction cups. In this case, the (passive) suction cup that does not apply the vacuum serves only as a contrast element to hold the bottle still when it is contacted by the (active) suction cup of the other arm and to counteract the thrust that the opposite (active) suction cup exerts. on the bottle when it engages it. In both modes of operation, the arm carrying the passive suction cup cooperates in thrust relationship with the arm carrying the active suction cup to allow the correct positioning of the bottle. It will be appreciated that the passive arm allows to eliminate the traditional fixed stops provided in proximity to the conveyor and their adjustment to adapt them to the format of the bottle treated each time.

The column 19 is then lifted (FIG. 8) to lift the bottles from the conveyor and taken to a position where they do not interfere with either the sides of the conveyor or with any other object. In the example shown, six bottles are lifted at a time. Keeping the vacuum applied to a single suction cup (active suction cup) of the two suction cups of each a pair of arms, the lifting of the arm that does not carry the active suction cup is first commanded (FIG. 9). In this position the bottle is held only by the active suction cup and is oriented vertically. The rotation of the active suction cup can then be controlled, by activating the actuator 28, by rotating the bottle horizontally (FIG. 10). In the horizontally rotated position, the active suction cup holds the bottle from above, i.e. with the side of the bottle body where the suction cup is applied facing upwards.

If you want to position the bottles in the box orienting them all in the same direction, that is with the caps all facing the same side, you have to activate the suction cups arranged on the same side, and lift the arms arranged on the other side.

If, on the other hand, one wishes to position the bottles in the box by orienting them in an alternating direction, according to the expression tete-bèche, that is to say by placing the cap of a bottle next to the bottom of the adjacent bottle, it is necessary to activate the suction cups of the various gripper devices 23 of the tested alternately: i.e. if the suction cup located on one side is activated in a given gripper device, in the immediately adjacent gripper device the suction cup located on the opposite side must be activated, and correspondingly lift alternately the arms that do not carry the suction cups activated in that cycle (FIG. 11 and 12).

The head 18 is moved towards the loading station B. The steps described above (displacement of the articulated arms which do not carry the active suction cups, and subsequent rotation of the active suction cups) can advantageously take place while the head 18 is moving towards the loading station. As mentioned, the head 18 is first raised by raising the column 19, then the carriage 17 is moved along the beam 16 towards the loading station B.

If the bottles are to be laid down in alternating orientations (tete-bèche), before inserting the bottles into the carton, the caps and bottoms of the bottles must be longitudinally aligned (FIG. 13, 14, 15). This phase is carried out by bringing the arms that bring the active suction cups closer towards the central plane of the head, i.e. by sliding the transversal slides 30, 31 towards the central plane V. The transmission with which the sliding movements of the slides are carried out can be such that a single command given to the slides causes both transverse slides of the same gripper device to move simultaneously in opposite directions. This can be achieved, for example, by means of a rack having a transverse shaft with threads oriented in opposite directions for the two slides, left and right, of the same gripper device.

In order to correctly position the bottles in the separators provided in the box, the bottles must be spaced longitudinally from each other. This step is carried out by activating actuators which cause the transverse guides 32 to move away from each other in the longitudinal direction along the longitudinal guides 40 (FIG. 16).

The bottles withdrawn from the head are then each suspended from a suction cup, oriented horizontally, aligned in the longitudinal direction and spaced from each other in the longitudinal direction (FIGS. 17 and 18). In this condition, the head 18 can be lowered until the bottles are placed in the respective seats D, E of one or more separators F placed in one or more respective open boxes aligned in longitudinal direction on the outlet conveyor in the loading station.

It will be appreciated that thanks to the choice of using gripping arms of the articulated parallelogram type, the arm (24 'and 25' in FIG. 19) which does not hold the bottle remains raised in a position close to the center line, and therefore does not interfere with the edges of the box S, especially when the clamp device is in the lowest position for placing a bottle in the lower part of a box (FIG. 20).

A lower layer of bottles was thus formed. In order to lay a subsequent overlying layer, the head 18 is raised together with the column 19. The trolley 31 moves back above the inlet station A. The various gripping devices 23 on the head are brought closer together, making them move closer together longitudinally the transverse guides 32 along the longitudinal guides 40. The two slides 30, 31 which carry the respective articulated arms of each gripping device are moved apart along the respective transverse guide; the articulated arms are returned to the raised position. The suction cups 27 are rotated so as to face each other. A new row of bottles to be picked up is ready on the inlet conveyor. The bottles are pushed into contact against each other and each gripper device is aligned in a vertical plane with a respective bottle to be picked up from the first conveyor.

A gripping head 40 of the separators F can in the meantime take one or more new separators from the stacks P of the separator magazine and place them in the boxes on the bottles of the layers previously laid.

Depending on the type of orientation to be obtained, the separators can be arranged oriented exactly like the separators previously laid, or with an inverted orientation of 180 ° in the horizontal plane for an arrangement with alternate orientations (tete-bèche), FIG. 25, 26. In the first case, the operations of the laying cycle of the second layer are carried out exactly as described above. In the second case, each gripper device must take a bottle and lay it down by rotating it in the opposite direction (FIG. 21, 22) with respect to what was done in the previous cycle (FIG, 23, 24). To do this, the suction cups that in the previous cycle had acted as active suction cups are now used as a contrast, at most activating them only in the initial phase of lifting the bottles from the conveyor. Conversely, the suction cups that in the previous cycle were used as non-active suction cups, in the following cycle are also activated to rotate the bottles and hold them horizontally until they are placed in the separators arranged in the boxes.

It will be appreciated that with a single gripping head it is possible to arrange the bottles in the box according to any desired orientation: identical for all the bottles, or with alternating orientations between the bottles of the same layer, possibly with an alternating sequence in reverse with respect to the bottles of the underlying layer. or above.

The commands that cause the selective operation of the various actuators for moving the gripper devices are produced by the effect of commands given by a processing unit - typically a PLC or Programmable Logic Controller or a PC (Personal Computer) - which supervises the operation of the machine. as a whole, therefore also to the operation of all the other motor / actuator members described here.

According to an alternative embodiment of the invention (FIG. 27-29), the gripper device can be provided with a single suction cup 27, located on one (25) of the two arms. The other arm 24 serves in this case only to provide a mechanical contrast which facilitates an effective gripping of the article (bottle) and allows to eliminate the traditional mechanical stops and the relative adjustments. Experimental tests carried out by the Applicant have shown that even this simplified variant allows to increase the gripping speed and ensures excellent stability at the moment of vertical lifting acceleration.

Along the head, the suction cups of the gripper devices can be arranged either all on the same side, or alternated. The first variant only allows you to lay the bottles all in the same orientation, that is, with the cap turned to one side. The second variant makes it possible to create layers of bottles where in each layer the bottles are oriented alternately in opposite directions, but with the same sequence with respect to the other layers.

According to an embodiment, the magazine C of the separators can be moved with an alternating translating motion in the longitudinal direction and have stacks of separators arranged with alternately opposite orientations. The head 40 for picking up and placing the separators moves between the loading station B and the separator magazine C. Advantageously, the number of stacks of separator sheets is greater than the number of cardboard boxes (two in the example illustrated) than the laying of the separators can serve simultaneously. During a cycle of formation of a layer of bottles in the boxes, the separator magazine is translated into a first longitudinal position in which the separator laying head can take two separator sheets with opposite orientations from two adjacent stacks, and place them in as many ( two boxes. In the next cycle, the magazine is moved by the existing pitch between two consecutive stacks so that the head, while always moving to the same longitudinal pick-up position, is able to pick up two separators each oriented in the opposite direction with respect to the homologous separators picked up in the previous cycle. The number of separators that can be taken from a single head at each cycle is variable. If the head is single, the stacks of separators on the translating magazine will be at least two. If the head is double, the stacks of separators on the translating magazine will be at least three, and so on.

The transverse support guides of the gripper devices 23 can be conveniently disassembled from the connections 21 of the head 18 (of the combined self-adjusting type) and can be replaced with a bell-type gripping unit 42, which grips the bottles by the neck (FIG. 30) . This allows the cartoning machine to be used as a combined machine, ie capable of alternatively carrying out the laying of the articles horizontally or vertically.

Various aspects and embodiments of the cartoning machine have been described. It is understood that each embodiment can be combined with any other embodiment. Furthermore, the invention is not limited to the embodiments described, but may be varied within the scope defined by the appended claims. In particular, the number of gripping devices may differ from six.

Claims (8)

CLAIMS 1. Cartoning machine, comprising: an inlet station (A) with an inlet conveyor (12) extended in a longitudinal direction (x) to feed at least one longitudinal row of vertically oriented articles (1); a loading station (B), placed side by side to the inlet station (A), with an outlet conveyor (13) adapted to carry at least one box (S) open upwards; a movable head (18) suitable for cyclically picking up a plurality of said vertically oriented articles (11) from the inlet station, rotating the articles by 90 ° in parallel vertical planes and placing the articles oriented horizontally and in overlapping rows, in said at least one box in the loading station (B), where the movable head comprises at least one pair of parallel longitudinal guides (40) carried by the movable head, a plurality of transverse parallel guides (32), movable longitudinally along the longitudinal guides (40), a plurality of pairs of slides (30, 31) mounted transversely and sliding along respective transverse guides, a plurality of gripper devices (23) for gripping and rotating the articles, where the gripper devices (23) are longitudinally aligned along the movable head (18), and each gripper device (23) comprises a pair of arms (24, 25), mobile and substantially symmetrical with respect to a longitudinal vertical plane (V), and where each movable arm (24, 25) is carried by a respective one of said slides (30, 31), at least a first (25) of the two arms of a pair (24, 25) is provided with a suction cup gripping means (27) able to engage a first side of one of said articles (11), the suction cup gripping means being rotatably mounted about a horizontal axis (26) and an actuator (28) for rotating the suction cup means about the axis (26), and at least the other (24) of the two arms of the pair is movable between a lowered position, in which it can engage a second side, opposite to the first side, of one of said articles, and a raised and passive position, in which said other arm (24) is moved away from the first arm (25) in order not to interfere with an article (11) held by the suction cup means (27) on the first arm (25) when this suction cup means is rotated about the axis (26). 2. Cartoning machine according to claim 1, wherein the two movable arms (24, 25) of each gripper device (23) are two articulated arms. 3. Cartoning machine according to claim 2, in which the two articulated arms (24, 25) are symmetrical with respect to a longitudinal vertical symmetry plane (V), so as to engage one of the articles respectively on the first and second side substantially to a same height. Cartoning machine according to claim 2 or 3, wherein each articulated arm comprises an articulated quadrilateral (29) having: a rod (34) which has at one end the suction cup gripping means (27) or an engagement element able to cooperate in thrust relationship against said second side of the article (11), a pair of levers (35, 36) hinged to the rod (34) and to a support (37) fixed to one of the transverse slides (30, 31); an actuator (39) which can be commanded to rotate the articulated arm between a lowered position, in which the suction cup gripping means or the engagement element can engage one side of one of said articles, and a raised and passive position, in which the articulated arm is moved away from the other articulated arm of the same pair. 5. Cartoning machine according to any one of the preceding claims, in which both movable arms (24, 25) each have a respective suction cup gripping means (27), 6. Cartoning machine according to claim 5, in which the suction cup means (27) of the two arms (24, 25) of each gripper device (23) can be activated selectively. Cartoning machine according to any one of the preceding claims, in which the transverse guides (32) are associated with attachments (21) which allow the transverse guides (32) to be released from the longitudinal guides (40). 8. Cartoning machine according to any one of the preceding claims, further comprising: a longitudinally translating magazine (C) of reciprocating motion, transversely flanked to the loading station (B), on the opposite side of the inlet station (A); where is it the translating magazine (C) comprises a plurality of stacks (P) of horizontal separator sheets (F), the piles (P) are aligned parallel to the longitudinal direction, the separator sheets in each stack (P) are oriented in a direction opposite to the direction in which the sheets (F) in the two stacks adjacent to the stack in question are oriented; And a movable head (40) able to cyclically pick up one or more sheets (F) from two or more adjacent stacks (P) of the warehouse (C) and to place the picked sheets in one or more open boxes (S) longitudinally aligned on the conveyor in exit (13), and where the number of stacks (P) of horizontal separator sheets (F) is greater by at least one unit than the number of boxes (S) in which the movable head (40) places the separator sheets at each cycle.