FI79972B - CIRCULAR MACHINE FOR AUTOMATIC FRAMSTAELLNIG AV UTSTAELLNINGSFOERPACKNINGAR. - Google Patents

Description

1 79972

The present invention relates to an apparatus for shaping cardboard blanks, in particular for making boxes, the device having a transport wheel rotating about an axis; a plurality of suction boxes adapted to the transport wheel, connected to a vacuum source and adapted to receive the blanks; a plurality of workstations arranged around predetermined wheels in predetermined angular positions and comprising at least one feed station, one processing station, and one receiving station; and control means for ensuring periodic angular displacement of the transport wheel by moving the simulation bags from one workstation to another and for controlling each said workstation after each angular displacement of the transport wheel.

DE-A-15 61 429 discloses this type of device. In this known device, the transport wheel is a mandrel wheel rotating about a horizontal axis. With this device, the cardboard blanks are folded and glued together to form a box.

It is an object of the present invention to further develop a device of the type described above which is suitable for joining a blank and a plastic blank.

This object can be achieved by the device according to the present invention, characterized in that it comprises a second feed station for feeding plastic blanks, a check station for detecting the presence of blanks and a high frequency mounting station for joining both blanks, the suction boxes being adapted to receive blanks. .

2 79972

With the device according to the invention, a cardboard blank and a plastic blank can be joined together, which enables the manufacture of display boxes. Such boxes have an opening that extends over at least one edge and is closed by a rigid, transparent plastic sheet. Such display boxes and their manufacturing methods are described in FR patent 24 96 052 and FR supplementary patent 25 08 870.

With the device according to the invention, the blanks on top of each other can be arranged in a precise position with respect to each other in a simple manner thanks to the suction boxes. The device also achieves high working speeds.

The device according to the invention ensures that the cardboard blank is first placed on top of the suction box. The box is then taken to the plastic blank feed station. The plastic blank is placed on top of the cardboard and held in place by the suction of the box, which acts through the opening or openings in the plate. At the same time, another cardboard blank is placed on the next box.

Preferably, in the device according to the invention, each feeding station and receiving station comprises a structure arranged radially with respect to the plate and which rests partially on the latter; a plate disposed in a vertically movable manner on the structure; a movable body mounted on radial rails located at the top of the structure and movable between a first station in which it rests on a plate and a second station in which it rests on a suction box; suction pipes mounted on frame crossbeams and connected to a vacuum source; and control means for moving the body or crossbars to the lower position and the upper position.

These drives are relatively simple and easy to use structures. The picking up and lowering of the blanks by means of pipes mounted on a movable frame allows the blanks to be precisely positioned on top of the suction boxes 3 79972. Such a feeding station is in particular intended for handling cardboard parts, comprising a plurality of openings for the simultaneous assembly of several boxes, which boxes are then cut or separated from one another in accordance with the additional patent cited above.

Feeding separate plastic blanks requires greater accuracy.

This is achieved in that the plastic blank feeding station includes a removable guide plate fitted to the movable plate and having a plurality of vertical guides between which the blanks are placed on movable, small tables vertically, the fixed plate being placed on top of the movable plate and below the movable tubular body. on its lower surface, a number of fixed guides are supported, the cross-section and arrangement of which correspond to the vertical guides, and that there are numerous openings in the fixed plate between the guides for the passage of the blanks.

In this way, very precise control and positioning of the blank is achieved. This control system is simple and can be easily changed according to the size and shape of the blanks to be fed.

In order to avoid the simultaneous picking of several blanks from the stack, said fixed guides according to the invention, close to their upper end and guide surfaces, comprise a plurality of openings or holes connected to a source of compressed air.

Such a feed station can also be used when it is desired to lower several individual cardboard blanks at the same time to form one box. In this case, the guides are located at the corners of the openings in the blanks.

4,79972

In a particularly preferred embodiment of the invention, the mounting station comprises a high frequency press with a fixed jaw below the plate and a movable jaw above the plate, the suction boxes being supported relative to the plate by bearings connected to vertical pins fitted to the plate and against the opening.

Said bearing and said vertical bars preferably have internally cylindrical parts with a deformable seal between them and the outer upper parts of which are conical.

Thanks to this structure, the expansion of the boxes is largely compensated by the heat generated by the hair press. In addition, it is ensured that the boxes move exactly parallel between the two jaws of the press.

For attaching and notching plastic blanks, it is also possible to install two separate high-frequency clamps on two consecutive workstations.

Furthermore, in order to prevent disturbances of the automatic control devices according to the invention caused by the magnetic fields produced by the operation of the press and to electrically separate the press from the circular plate control means, the starting of the press from the station is controlled by an electro-optical gate. Said press comprises two slides between the compressed air source and two pressure equalizers connected to the control circuit, whereby the slides can be moved to their open position by means of switches operated by a movable jaw.

In order to avoid damage to the press and the boxes when it happens that the boxes are in a different vertical position, said plate between each pair of boxes includes a cam which is connected to a fixed boundary connected to the control circuit.

Il 5 79972

In order to ensure a suitable high-frequency fastening between cardboard and rigid plastic blanks in such a device, it is usually necessary to first cover the second blank with a liquid that allows this fastening. This operation is usually carried out in two different steps on a special machine and thus constitutes an expensive pretreatment, including further processing of the blanks.

To avoid this disadvantage, the device according to the invention further comprises a coating station below the cardboard blank feeding station or the plastic blank feeding station, in which the cardboard blanks or plastic blanks are treated with a liquid to provide an adhesive bond between the blanks.

Said coating liquid preferably consists of an aqueous dispersion based on polyacrylic esters of the copolymer polyvinyl acetate type with 5% solvent. Such a coating liquid allows treatment in one step, but it is also possible to use vinyl adhesive as the coating liquid.

According to a particularly preferred embodiment, said coating station comprises a constant-surface container containing the coating liquid and arranged radially outside the circular plate opposite the suction box; a lower body having hollow fibers on its upper surface, the arrangement of which corresponds to the position of the fastening lines between the blanks, and which is movable vertically; an upper body having strips of flexible and absorbent material on its lower surface, which follow the lines of attachment considered, and which is movable horizontally radially by means of guide means.

According to a preferred embodiment, the upper body guide means consists of at least one lifting device, the arm of which is connected to the frame, the upper body having an opening above which a second lifting device is mounted, the arm 6,79972 having a slider movable over the opening for the blank to be coated. In this way, the complete positioning of the blanks during coating is ensured.

The coating liquid can be applied to either a cardboard blank or a plastic blank. When high-frequency notching is performed in the same device, the coating liquid must be placed on the plastic blank.

Other embodiments and advantages of the invention will become apparent from the following description and accompanying drawings, which show an example of an illustrated embodiment of the device according to the invention.

Figure 1 is a schematic view of a complete device according to the invention; Figure 2 is a very schematic view of a cardboard sheet or blank feeding and receiving station; Fig. 3 is a partial side elevational view showing in more detail a receiving station very similar to a cardboard sheet feeding station; Figure 4 is a front and partially side elevational view of the plastic blank feed station; Figure 5 is a perspective view of the controls of the station shown in Figure 4;

II

7 7,772 Fig. 6 is an elevational view of the suction pipe control members of the various stations shown in Figs. Fig. 7 is a schematic view of a partially sectioned suction box of the rotating plate of the device shown in Fig. 1; Figure 8 is a cross-sectional view taken at VIII-VIII in Figure 7; Figure 9 is a cross-sectional view taken along line IX-IX of Figure 7; Figure 10 is a schematic cross-section of a high frequency mounting and / or notching station; Figure 11 shows the guide members of a circular plate; Figure 12 shows schematically the control and start-up of a high-frequency press; Fig. 13 is a schematic, vertical, cross-sectional view showing the upper body of the coating members according to the invention in position above the lower body; Fig. 14 is a schematic, vertical cross-sectional view showing the upper body in position above the circular suction box of the device shown in Fig. 13.

The device according to the invention shown in Figure 1 consists essentially of a horizontal circular plate 1, which is rotatably driven by means of a known motor and transmission. These members ensure the periodic displacement of the plate 1 by a predetermined angular distance corresponding to the distance between two adjacent workstations located on opposite sides of the plate.

In the embodiment described here, the device consists of six workstations around the plate 1, which are located at a certain angular distance from each other. These workstations consist of a station 2 for feeding cardboard blanks, a station 3 for feeding plastic blanks, an inspection station 4, an attachment station 5, a second inspection station 6 and a receiving station 7 for removing the assembled blanks.

On the opposite side of the workstations, six suction boxes 8, 9, 10, 11, 12 and 13 are mounted on the plate 1, one of which is e 79972 shown in detail in Figures 6-8. Each box is connected by a flexible pipe 14 and through a transverse inlet valve 15 and an outlet valve 16 to a central vacuum generator 17, which is not shown in detail here. There are known rotating connectors 18 between the pipes 14 and the generator 17. The control means of the valves 15 and 16 will be described later when the operation of the device according to the invention is described.

Each workstation 2, 3 and 7 has a general structure, which is shown very schematically in Figure 2. Part of the receiving station 7 and part of the plastic blank feeding station 3 are shown in more detail in Figures 3 and 4, 5 respectively.

Each station 2, 3 and 7 comprises, outside the plate 1, a structure consisting of vertical beams 19, 20, bearing horizontal rails 21, 22, the differences of which essentially correspond to the lengths of the suction boxes 8-13. The rails 21, 22 extend above the plate 1 to the inner ends of the suction boxes. Mounted on the rails 21, 22 is a movable body 23 comprising crossbars 24 on which suction openings 25 are made. The body 23 can be moved to a position where it is above the suction box, for example 13, as shown in Figure 3, and pulled back to another position where it is outside the plate. The outer part of the plate 1 of the structure 19, 20 has a movable feed or receiving plate 26 which can be moved horizontally and which is controlled by a chain drive which is not shown. In Figure 3, only one attachment point 27 can be seen connecting the chain of this device. At the level of the plate 26 there is a structure 19, 20 and the rails 21, 22 are arranged with known edge positioners, for example consisting of adjustable stops 28, 29.

The ducts 25 are connected by a most flexible tube to a vacuum source, not shown here. Known control

II

9,79972 means for connecting or disconnecting pipes 25 to this vacuum source. The frame 23, which carries the crossbars 24 in the channels 25, is moved by a double-acting lifting device 30, shown in Fig. 3.

In addition, the body 23 and the channels 25 can be lowered and raised to pick up or remove the cardboard blank or plastic blank. The means for controlling these movements are shown in more detail in Figure 6. This figure shows a tube 25 attached to a crossbar 24 which in turn is connected near its ends to vertical bars 31, 32 extending upwards through a tubular guide 33, 34 attached to the structure. Each rod -31, 32 comprises an end 35, 36 larger than its upper end, which acts as a retainer for a coil spring 37 located between said end of the rod and the upper end of the guide 33, 34. This spring 37 helps to keep the rod 31, and thus the tube 25, in the upper position (as shown in the right-to-left part). To control the lowering of the pipes, the structure has a lifting device 38, the arm 39 of which is connected at its free end to the free end of the double lever 40. This lever 40 is placed on a pin 41, on which a lever 42 is also placed.

The other end of the lever 42 is positioned above the rod 32. The free end of the second lever 43 placed on the pin 44 is above the rod 31. A lever 45 is also placed on the latter pin, the free end of which is connected to the other free end of the lever 40 by means of an articulated rod 46.

When the lifting device 38 is operated, its arm 39 causes the lever 40 to turn counterclockwise. The levers 42 and 43 lower down and push the rods 31, 32 down against the spring 37. The tubes 25 thus land on the blanks for lifting and lowering to the suction box of the plate 1.

The structure of the feed station 3 of the plastic blanks 55 'differs slightly from the positions 2 and 7 and in particular comprises means for precisely controlling the blanks as shown in Figures 4 and 5.

The plastic blank feeder comprises means for lifting and moving by means of tubes similar to the cardboard blank feeders 2 and a receiving station 7 as shown in Figures 2, 3 and 6, described above. For clarity, these organs are not shown in Figure 4.

The station shown in Figure 4 comprises a receiving plate 46 corresponding to the plate 26 at positions 2 and 7. The plate 46 is laterally adjustable by a manual control unit including a floating angle guard 50 fixed to the inner surface of the plate 46 and communicating with an endless screw 51 movable by handwheel 52.

The plate 46 is arranged to support a guide plate 53, on which are mounted a plurality of vertical guides 54, between which plastic blanks 55 'are placed, as shown in FIG. These plates 55 'have notches 56 at the ends of the fold lines 57. These notches 56 are in the shape of a strongly beveled cone and the guides 54 are arranged on the plate 53 so as to mate with the notches 56 and have a shape corresponding to the shape of the latter. Adjacent guides 54 remain in place in the intermediate space by means of adjusting rods 58. Each guide 54 has a wider portion 59 at its lower end which allows attachment to the plate 53 with screws 60. This arrangement is particularly simple and allows the guides 54 on the plate 53 to be quickly adjusted to the size and shape of the blanks 55 '.

In order to allow control of the blanks 55 ', which are superimposed in a stack shape between the guides 54, the parts of the latter corresponding to the notches 56 have been slightly enlarged at the bottom of the guides. In this way, the blanks are caught between the guides as they move upwards. To control this movement, the blanks 551 are on small plates 61, 11,79972, which extend between the guides 54 and are supported by a guide plate 62 movably mounted vertically.

The movement of these plates 63 is controlled by the chain transmission shown in Figure 4 by a single chain 64 attached to the plate 62. This chain is driven by a gear 64 connected to the shaft of the adjusting motor 65.

Above the movable guides 54 are fixed guide units 66, supported by a plate 67, which are quite connected 68 to the structure of the plastic blank feeding station.

The guides 66 are positioned directly along the guides 54, and the plate 67 has openings 69 for the passage of the blanks 55 '. To prevent the uppermost blanks 55 'from sticking to the stack of blanks 61 on the narrow plates 61, the fixed guides 66 have openings at their upper ends through which compressed air is blown, as indicated at 70. This arrangement ensures that the tubes at this station lift only one separate blank 55 'from the stack during each operating cycle.

The structure of the various suction boxes 9-13 of the circular plate 1 is shown in detail in Figures 6, 7 and 8. Each box is formed of a rectangular element or housing divided by vertical walls 71 into a plurality of compartments 72 connected and connected as shown in Figure 1 by a flexible tube. 14 and valves 15 to the vacuum source 17. The top surface of each box is closed by a metal plate 73 with a plurality of holes 74 which ensure suction for the cardboard blanks 55 and the plastic blanks 55 '.

The boxes are fixed to the plate 1 by bearings 75 and 76, which have a considerable clearance, while the bearing 77 has only a limited clearance. The structure of bearings 75, 76 and 77 is shown in Figure 9, while the structure of bearing 78, which is different, is shown in Figure 8. The special structure of these bearings has proved necessary in passing boxes 8-13 through 12 79972 station 5 high frequency radiation mounting pressure and hot notching. In fact, at this station, the boxes are subjected in a high-frequency press (Fig. 9) to heating, which causes the structural material of the boxes to expand, especially the aluminum; wherein said expansion is large enough to compromise the position and vertical movement of the boxes and thus also the position and movement of the cartons and plastic blanks, taking into account the large attachment and / or hot release tools of the hair press.

These tools are not shown or described here because they correspond to the tools described in detail in the applicant's French patent and the additional patent cited above.

In order to compensate for said expansion and thus ensure fastening and / or notching with high accuracy, the boxes must be movably mounted horizontally and along two axes. In addition, in order to equalize the pressure on the entire surface of each box between the fixed jaw 89 and the movable jaw 90 of the high-frequency press (Fig. 10), the boxes must be movably mounted vertically relative to the circular plate 1.

Each bearing 75-78 comprises a stop 79 located at four corners of the box, a vertical opening 80 with a cover 81 containing an elastic joint 82. The cover 81 has a cylindrical lower portion 83 and a conical upper portion 84. The vertical portions of the cover 81 and the stop 79 there is free space or limited freedom of movement in between. A vertical rod 85 is attached to the opening 80, the lid 81 and the joint 82, which is fixed to the plate 1. This rod also has a lower cylindrical part 86 and a conical upper part 87. Between the plate 1 and the box there is a coil spring 88 on the rod 85 which tends to hold the box 9 at a specified distance above plate 1. In this upper position, the conical portion 87 of the rod 85 communicates with the conical portion 84 of the lid 81, and the box is immobilized and locked in a predetermined central position. It is held 13 79972 in this position when it is opposite workstations 2, 3, 4, 6 and 7.

On the other hand, when the box is moved between the fixed jaw 89 and the movable jaw 90 of the high frequency clamping and notching press 91 of the station 5 (Figure 10), and the press is turned on, the movable jaw 90 pushes against the springs 88 in the fixed jaw 89 of the box 9 'as described above.

In this state, the conical part 87 of the rod 85 disengages from the conical part 81 of the lid 80. In this way a certain clearance is created between the box and the rods 85, i.e. relative to the plate 1. The box 9 can thus be moved completely parallel to the jaws 89, 90 of the press 91. This is absolutely necessary to achieve good adhesion and / or notching of the plastic blank 55 ', as these functions are functions of the strength of the press, the pressure produced between the two jaws 89, 90 by the blanks 55 and 55' and the pressing time of the jaws of the press.

Bearing 78 (Figures 7 and 8) has essentially the same structure as bearings 75-77. But in this case, there is no room for movement between the cover 81 and the stop 79. In addition, the end of the rod is polygonal in cross-section as shown in Fig. 7.

To avoid damage to the press 91, the plate 1 comprises a fixed cam (Fig. 10) between each pair of boxes, which communicates with a fixed boundary 94 connected to the press control system. Limit 94 can only be activated at the marked position and triggers the press lowering. Should any accidental misalignment of the plate occur during lowering of the moving jaw of the press, the moving jaw will automatically return to the upper normal position.

In order to avoid interactions between the electrical circuits 91 of the press and the control system of the plate 1, the starting of the two elements is controlled by hydraulic and optical means, respectively.

Figure 11 shows schematically the control connection 102 of the plate 1. The press has two valves 95, 96 and are connected to a source of compressed air 97, comprising boundaries 103, 104, which are activated by the movable jaw 90 when in their upper position. Valves 95, 96 thus give an impulse to two pressure equalizers 98.99, one of which supplies supply current 110 to the starting circuit 101. The second pressure equalizer 99 receives the starting signal supplied by this circuit at the plate 112 connection 112. The latter can thus proceed only when the press jaw is in its up position.

The press is started via an electro-optical gate (Fig. 12) comprising a power supply 105 supplying a projector 106 placed at one end of the light guide 107. At the other end of this conductor is a photocell 108 which receives current through the amplifier 109 to the start-up circuit 110 of the press.

The coating device according to the invention shown in Figures 13 and 14 comprises a constant surface container 120 located radially outside the circular plate 1 of the device and opposite its suction box. The container 120 contains a coating liquid 121 which allows high frequency sealing between the cardboard blanks and the rigid plastic blanks. Such a substance may be a vinyl adhesive or, preferably, an aqueous dispersion based on polyacrylic esters such as those sold by BASF under the trade name "Acronal 300 D".

The container 120 has a lower body 122 movable vertically, which body comprises an upper surface 123 formed by fibers, the upper end of which has recesses 123 '. The shape of said fibers 15 79972 123 corresponds to the fastening lines to be formed between the blanks.

In the lower position of the lower body 122, the upper ends of the fibers 123 are below the surface of the coating liquid 121 so that the recesses 123 'are filled with the liquid 120. In their upper position, the fibers 123 are above the liquid surface of the container 120.

The upper body 124 of the coating device comprises on its lower surface strips of absorbent material 125, the shape of which corresponds to the fibers 123 of the lower body 122 and thus to the fastening lines to be provided.

The upper body 124 comprises control means which allow it to move vertically between the two operating stations. These members are shown schematically herein by cylinders 127 having arms 128 attached to the body 124. In addition, the upper body 124 has a central opening 129 above which is placed a cylinder 126 having a plastic slider 131 attached to the shaft 130 to compress the blank 55 and 55 'to be coated. The cylinder 126 also has a touch sensor 132 at the end of the stroke, which is activated when the slider enters its upper position. The body 124 is supported on a transfer tray, not shown here, which allows it to be moved horizontally between an outer position in which it is in a straight line above the lower body 122 and an inner position in which it is above the suction box 8. This transfer tray is of the same type as described in the second blank feed station.

The coating device according to the invention operates as follows:

Initially, the lower body 122 moves from the reservoir 120 to its upper position and the upper body 124 is in the upper and outer positions above the body 122. The cylinders 127 lower the body until its strips 125 meet the fibers 123 of the lower body 122 and thus raise the coating fluid in the recess 123 '. The cylinders 126 then raise the upper body 124 and the transfer tray (not shown) moves it ie 79972 above the suction box 8 with the blank to be coated, while the lower body 122 is moved to the lower position to refill the recesses 123 'with coating liquid -121.

Now the cylinders 127 and 126 lower the body 124 and the slide pusher 131, which ensures the position of the blank 55, 55 'relative to the suction box 8. In this position, the strips 125 deliver the coating liquid network to the blank. The cylinders 127 now lift the upper body 124, while the slider 131 remains to compress the blank to avoid any movement of it as the body 124 is lifted.

When the body 124 reaches its upper position, the slider 131 also returns to its upper position and contacts the touch sensor 132 at the end of the stroke, which controls the movement of the platform to return the upper body 124 to the outer position above the lower body 122. The latter is moved to its upper position and a new cycle can begin, in the meantime the circular plate 1 has moved one step.

According to the embodiment shown, said coating liquid contains an acetate polyvinyl copolymer in an aqueous dispersion of 5% solvent.

Claims (14)

17 79972 An apparatus for shaping cardboard blanks, in particular for making boxes, the apparatus having a rotating conveyor wheel (1); a plurality of suction boxes (8-13) fitted to the transport wheel, connected to a vacuum source and adapted to receive blanks; a plurality of workstations (2-7) arranged around predetermined wheel (1) in predetermined angular positions and comprising at least one feed station (2), one shaping station and one receiving station (7); and control means for ensuring a periodic angular displacement of the transport wheel (1) by moving the suction boxes (8-13) from one workstation to another and for controlling each said workstation after each angular displacement of the transport wheel 15, characterized by a second feed station (3) for feeding plastic blanks, inspection station (4) ) for detecting the presence of the blanks (55) and for connecting the two blanks of the high-frequency attachment station (5) to each other, the suction boxes (8-13) being adapted to receive the blanks to be connected and the transport wheel being a circular plate (1) rotating about a vertical axis. Device according to claim 1, characterized in that each feeding station (2, 3) and receiving station (7) comprises a structure (19, 20) arranged radially with respect to the plate (1) and partially resting on the latter; a plate (26, 46) disposed vertically movably on the structure 30 (19, 20); a movable body (23) mounted on radial rails (21, 22) located at the top of the structure (19, 20) and movable at a first position where it rests on the plate (26, 46) and a second position at which it rests on the suction box 35 (8-13); suction tubes (25) mounted on the crossbeams (24) of the body (23) and connected to a vacuum source; and control means (38-46) for moving the body (23) or crossbars (24) to the lower position and the upper position. is 79972 Device according to claim 2, characterized in that the feed station 5 (3) of the plastic blanks (55) comprises a removable guide plate (53) arranged on the movable plate (46) and having a plurality of vertical guides (54) between which the blanks are placed on moving small tables (61) in the vertical direction, that the fixed plate (67) is placed on the movable plate (46) 10 and below the movable body supporting the tubes (25), which on its lower surface supports a plurality of fixed guides (66) with a cross-section and arrangement corresponding to the vertical guides ( 54), and that the fixed plate (67) has a plurality of openings (69) between the guides (66) for the passage of the blanks (55). Device according to Claim 3, characterized in that the fixed guides (66) have a plurality of openings or holes (70) connected to the compressed air source close to their upper ends and on their guide surfaces. Device according to one of Claims 1 to 4, characterized in that the mounting station (5) comprises a high-frequency press (91) with a fixed jaw (89) below the plate (1) and a movable jaw (90) above the plate (1). that the suction boxes (8-13) are supported relative to the plate (1) by bearings (75-78) connected to the vertical pins (85) fitted on the plate (1), and that the boxes (8-13) are held in advance by elastic return means (88) at a certain distance from the plate (1), wherein the plate (1) has an opening (92) for each box (8-13). Device according to claim 5, characterized in that the bearings (75-78) and the pins (85) have cylindrical inner parts (83, 86) with a deformable seal (82) interposed between them and with outer outer parts (84). 87) is conical. i9 79972 Device according to Claim 5 or 6, characterized in that the clamp (91) of the fastening station (5) is actuated by means of an electron-optical gate (105-109). Device according to one of Claims 5 to 7, characterized in that the clamp (91) comprises 10 slides (95, 96) between the compressed air source (97) and two pressure switches (98, 99) connected to the control circuit (100-102). wherein the slides (95, 96) are movable to their open position by means of limits (103, 104) operated by the movable jaw (90). 15 Device according to one of Claims 5 to 8, characterized in that the plate (1) comprises, between each pair of boxes (8 to 13), a cam (93) which is connected to a fixed boundary (94) connected to the control circuit. Device according to one of Claims 1 to 9, characterized in that it comprises a coating station below the feed station (2) for cardboard blanks (55 ') or below the feed station (3) for plastic blanks (55), in which the cardboard blanks (55') or the plastic blanks (55) are treated with a liquid to provide an adhesive bond between the blanks. Device according to Claim 10, characterized in that the coating liquid is in the form of an aqueous dispersion based on polyacrylic ester. Device according to claim 10 or 11, characterized in that the coating station comprises a constant-surface container (120) containing the coating liquid and arranged radially outside the circular plate (1) opposite the suction box (80); a lower body (122) having hollow fibers (123) on its upper surface, the arrangement of which corresponds to the position of the fastening lines between the blanks and which is movable in the vertical direction; and an upper body (124) having strips (125) of flexible and absorbent material 5 on its lower surface, which follow the considered fastening lines, and which is movable horizontally radially by means of guide means. Device according to claim 12, characterized in that the control means of the upper body (124) consist of at least one lifting device (127), the arm (128) of which is connected to the body (124), the upper body (124) having an opening (129), above which a second lifting device (126) is mounted, the arm (130) of which has a slider (131) movable over the opening (129) for the blank (55, 55 ') to be coated. Device according to one of Claims 10 to 13, characterized in that the coating liquid contains an acetate-polyvinyl copolymer in an aqueous dispersion containing 5% of solvent. 2i 79972