EP1422143B1 - Apparatus for wrapping a load by means of a plastic foil - Google Patents

Description

Technical field of the invention

• un plateau tournant de support de la charge,
• des moyens support d'une bobine de stockage du film,
• des moyens d'actionnement en rotation du plateau,
• un dispositif de guidage multidirectionnel du film pour recouvrir sans discontinuité par banderolage la face latérale et la face horizontale supérieure de la charge, ledit dispositif étant intercalé entre la bobine et le plateau tournant, et comprenant des moyens de pivotement autour d'un axe de basculement entre une position horizontale et une position verticale, et des moyens de déplacement en translation entre une position abaissée et une position relevée, séparées l'une de l'autre par une course verticale ajustable en fonction de la hauteur de la charge.

The invention relates to a machine for packaging a load by means of a flexible plastic film, comprising:

• a turntable for supporting the load,
• support means for a film storage reel,
• means for actuating the plate in rotation,
• a device for multidirectional guidance of the film for continuously covering by wrapping the lateral face and the upper horizontal face of the load, said device being interposed between the spool and the turntable, and comprising means for pivoting about a tilting axis between a horizontal position and a vertical position, and translational displacement means between a lowered position and a raised position, separated from each other by an adjustable vertical stroke as a function of the height of the load.

State of the art

A wrapping machine by wrapping a palletized load of parallelepiped shape is known from the document EP-A-0 467 729 in which the same film is used to obtain a total overlap of the four planes of the lateral face, and the upper horizontal face. The film storage spool is rotated to the horizontal position at the beginning of the wrapping cycle, when the upper face is covered, and at the end of the cycle to perform the weld. The coil is actuated on the other hand to pivot to the vertical position to perform the wrapping of the side face. Stop means are necessary to ensure a positive locking of the axis of the coil in the two operating positions. At this double orthogonal pivoting of the coil, is added in addition to a vertical sliding movement by means of a movable carriage on which is mounted the coil. Such kinematics is complicated, and does not allow the use of large film coils. The pivoting assembly of the spool on the carriage complicates the loading of the spool, and the passage of the wrapping film. The pre-stretching device must also be pivotally mounted to follow the spool.

The document EP-A-0 522 928 discloses a wrapping wrapping machine, wherein the bobbin supporting means comprises a vertical mast and a movable carriage mounted to vertically slide and pivot about an axis. The reel thus describes a double movement of sliding and rotation along a ring surrounding the table.

In order to deposit a packaging film on the vertical planes of the lateral face, and on the upper face of a palletised load, the shading technique with stretch or heat-shrinkable film is also known. This technique is more difficult to implement than that of wrapping.

The document US-A-4,409,776 relates to a packaging machine by wrapping a palletized load with a film having a tacky side. A first layer of the film is applied to the load, the non-tacky side facing the load. A reversal of 180 ° of the coil orients the sticky side of the film on the coil facing the sticky face of the first layer of the film wrapped on the load. The wrapping of the second layer ensures the adhesion of the two layers of film.

The document US 5,140,798 discloses a wrapping machine according to the preamble of claim 1. The spool extends vertically, with the pivoting guide device directly receiving the film from the spool. The stretch film used has a tacky side to obtain good cohesion by superimposing the layers. Such a device can cause an uncontrolled conformation of the film between the coil and the application device, the film guidance not being positively controlled during the pivoting of the application device. This results in a high risk of sticking the film on itself during the pivoting movement of the application device.

Object of the invention

The object of the invention is to overcome the aforementioned drawbacks, and to achieve a packaging machine by wrapping, to increase the rates by the use of a large film reel, regardless of the layout of the coil, and accurately apply the film flat on top of the load with a minimum of pleating to ensure a good seal.

The packaging machine according to the invention is characterized in that the multidirectional guiding device forms an assembly comprising a pair of guide rollers between which the film passes, and an inclined deflection device.

The presence of this multidirectional guiding device makes it possible to use the same film without discontinuity for covering the lateral face and the upper face of the load, always keeping the reel in the same direction, without tilting movement.

According to a preferred embodiment, the film storage reel and the multidirectional guiding device are mounted on a movable carriage constituting said translational movement means. The multidirectional guidance system comprises for example a pair of non-motorized rollers between which the film passes.

The film storage coil can also be fixed extending horizontally or vertically in the vicinity of the ground. The film is then brought to the multidirectional guidance via an accumulator device placed before the return device.

In the case of a machine employing stretch film, the film can be wound on the reel in a pre-stretched state. It is also possible to make use of a pre-stretching device for the film disposed at the exit of the reel, and comprising a pair of motorized rollers making it possible to reel the film downstream at a speed greater than that upstream. . The stretched film flow rate is advantageously controlled by speed and / or force measuring means for controlling the application force of the film on the load.

According to another variant embodiment, the pre-stretching device of the film is associated with the multidirectional guidance system.

In the case of a machine employing heat-shrinkable film, the load packaged by wrapping on the tray, then passes into a retraction station containing heating means for effecting heat shrinkage of the film on the load.

Brief description of the drawings

• la figure 1 est une vue schématique en perspective d'une machine d'emballage par banderolage selon l'invention, la bobine pouvant se déplacer parallèlement à l'axe de rotation de la charge ;
• les figures 2 à 12 illustrent les étapes successives de fonctionnement de la machine d'emballage de la figure 1 ;
• la figure 13 montre une vue similaire de la figure 1, illustrant une variante de réalisation à bobine fixe et plateau tournant ;
• la figure 14 représente une vue partielle de la figure 13 dans la phase de recouvrement de la face horizontale supérieure de la charge.

Other advantages and features will emerge more clearly from the following description of an embodiment of the invention given by way of non-limiting example, and represented in the accompanying drawings, in which:

• Figure 1 is a schematic perspective view of a packaging wrapping machine according to the invention, the coil being movable parallel to the axis of rotation of the load;
• Figures 2 to 12 illustrate the successive steps of operation of the packaging machine of Figure 1;
• Figure 13 shows a similar view of Figure 1, illustrating an alternative embodiment of fixed coil and turntable;
• Figure 14 shows a partial view of Figure 13 in the recovery phase of the upper horizontal face of the load.

Description of a Preferred Embodiment

With reference to FIG. 1, a machine for packaging a palletized CH load comprises a reel 11 for storing a flexible film 12, a rotating plate 13 serving to support the load CH of parallelepiped shape, means for actuating 14 in rotation of the plate 13, and means of orientation of the film 12 to cover by wrapping the side face 16 and the upper horizontal surface 17 of the charge CH.

The lateral face 16 of the load CH comprises four planes 16a, 16b, 16c, 16d disposed in vertical planes parallel in pairs, and defining at the four corners of the vertical ridges 19 parallel to the axis of rotation 20 of the load CH.

The film 12 used is a width of stretchable or heat-shrinkable plastic material, especially polyethylene, said width being wound on the coil 11 along a horizontal axis orthogonal to the axis of rotation 20 of the load CH. For example, the width of the width may be between 500mm and 1500mm, while the height of the load CH is generally greater than said width.

In the case of a stretchable film 12, pre-stretching takes place before it is deposited on the load CH, for example by means of a film directly wound in the pre-stretched state (in the case of the example illustrated in FIG. 1).

It is also possible to obtain pre-stretching by means of a pair of motorized or non-motorized rollers at the outlet of the spool 11, so that the film 12 is unwound downstream at a speed greater than the speed upstream (see Figure 13).

The orientation means of the film 12 after unwinding of the coil 11, are constituted according to the invention by a multidirectional guidance system comprising a pair of guide rollers 21 between which the film passes, and a return device 28 to 45 °, the assembly being interposed between the coil 11 and the rotating plate 13, and mounted to tilt about a horizontal axis 22 so as to occupy either a horizontal position or a vertical position. The return device 28 at 45 ° is interposed between the coil 11 and the two guide rollers 21 so as to position the width of film 12 parallel to the side surface 16 of the load CH.

The spool 11, the deflector 28 and the pair of guide rollers 21 are carried by a movable carriage CM capable of moving in the vertical direction between a low position (FIGS. 2 and 3) and an extreme high position (FIG. ). The vertical stroke of the CM carriage between the two extreme positions is adjustable according to the height of the load CH.

The rotating plate 13 comprises a retaining clip 23 adapted to retain an end portion of the film 12 deposited at the base of the load CH, said clip being able to be equipped in addition to means for welding and cutting the film to ensure operation automatic production line.

The successive steps of operation of the packaging machine 10 according to the invention are illustrated in FIGS. 2 to 12, the same film being used both for the seamless covering of the upper face 17 and the lateral face 16. of the charge CH:

In the first step of starting the cycle illustrated in FIG. 2, the charge CH is deposited on the plate 13, which is rotated in the direction of arrow F1 by the actuating means 14, constituted by way of example by a geared motor. The end of the film 12 is held during the rotational movement of the load CH by the retaining clip 23 in the closed state. The support carriage CM of the deflection device 28 and the guide rollers 21 is placed in the lowered position, so as to start the wrapping of the side face 16 from the base of the load CH. The guide rollers 21 and the deflection device 28 are rotated a quarter of a turn in the direction of the arrow F2 towards the horizontal position, allowing the start of flat winding of the film 12 over a reduced width of the different planes 16b , 16c, 16d.

In FIG. 3, an upward movement of the carriage CM drives the guide rollers 21 and the return device 28 upward allowing the film to be deposited on the faces 16a, 16b without trapping the retaining clip 23. A movement is then made. descending the carriage so as to cover the reduced width of the film, allowing the opening of the clamp 23. The guide rollers 21 and the deflection device 28 remain in a horizontal position during this first step.

In FIG. 4, the guide rollers 21 and the deflection device 28 are tilted towards the vertical position (arrow F3) in order to position the film 12 parallel to the lateral face 16 before it is deposited on the load CH. The CM trolley slide towards the high position (arrow F4), until the guide rollers 21 slightly exceed the horizontal plane of the upper face 17 of the load CH. During this vertical sliding movement of the carriage CM, the film 12 envelops the whole of the lateral surface 16 of the load CH following the rotation of the plate 13 in the direction of the arrow F1.

With reference to FIG. 5, the guide rollers 21 and the deflection device 28 pivot towards the horizontal position (arrow F5) with a raising and lowering movement of the carriage CM intended to apply the film 12 to cover a part of the upper face 17.

In Figure 6, the guide rollers 21 and the deflector 28 pivot in the opposite direction to the vertical position, while the carriage CM remains in the up position. The film 12 is then ready to be deposited in parallel on one of the planes of the lateral face 16.

During these operations, the load CH rotates continuously with or without variation of speed.

With reference to FIGS. 7 and 8, maneuvers identical to those previously described for FIGS. 5 and 6 are carried out so as to cover another part of the upper face 17. The support carriage CM of the spool 11, guide rollers 21, and the deflection device 28, remains in the high position during these operations. These operations can be repeated to ensure partial or complete sealing of the face 17 of the load CH.

Figure 9 shows the wrapping operation of the planes of the side face 16, by sliding the carriage CM to the low position, the guide rollers 21 and the deflection device 28 remaining held in the vertical position.

In Figure 10, the tilting of the guide rollers 21 and the deflection device 28 to the horizontal position provides a pleating of the width at a predetermined height of the base, for example between 3 cm and 20 cm. The open clip 23 recovers this folded part of the film during the continued rotation of the load CH on the plate 13.

In FIG. 11, the rotation of the plate 13 is stopped, without modifying the position of the carriage CM and of the guide rollers 21. The closure of the retaining clip 23 then makes it possible to cut the film strip 12 after having secured by welding the terminal part to the charge CH.

In FIG. 12, the charge CH packaged on its five faces is disengaged from the plate 13, which is immobilized in rotation. The film 12 held in the clip 23 is waiting for a new packaging cycle.

On the plate 13 can be mounted a handling table equipped with motorized running gear, transmission chains or a conveyor belt to automatically route the packaged CH load from an upstream station or evacuate to a downstream station.

In the variant embodiment of FIG. 13, the reel 11 for storing the film 12 is fixed while being arranged at a horizontal axis at ground level. At the exit of the reel 11 is a pre-stretching device 24 of the film making it possible to pre-stretch the film coming from the reel 11 before passing it through an accumulator device 25. The pre-stretching device 24 of a well known type comprises rollers 26 between which the film 12 passes, the rollers 26 being driven at different circumferential speeds by a geared motor mechanism 27 associated with a pair of gears 29, 30 of different diameters. The accumulator device 25 comprises a series of rollers spaced at various levels to store a certain length of pre-stretched film 12, allowing vertical movement of the carriage CM regardless of the height of the load CH. The return device 28 at 45 ° is interposed between the accumulator device 25 and the two guide rollers 21 so as to position the width of the film 12 parallel to the lateral surface 16 of the load CH. The two devices 25, 28 accumulator and return can move in vertical translation to perform a helical wrapping around the load CH. The spool 11 and the pre-stretching device 24 remain attached to the ground, or to a fixed frame.

In FIG. 14, the return device 28 at 45 ° and the guide rollers 21 swing (arrow F7) with respect to a horizontal axis to effect the covering of the upper face 17. The rest of the packing cycle is similar to that described previously.

According to another variant (not shown), the pre-stretching device of the film can be mounted on the movable carriage CM of Figure 1, so as to move with the coil 11 between the low position and the high position.

It is also possible to integrate the pre-stretching device in the multi-directional guide system of the film 12, for example by replacing the free rotating rollers 21 of FIG. 1 with motorized or non-motorized pre-stretching rollers, different speeds.

In the case of a heat-shrinkable film, the load wrapped by wrapping on the plate 13, then passes to a retraction station containing a hood or an oven for effecting heat shrinkage of the film on the load CH.

According to another embodiment, the carriage CM can be driven in a rotational movement around the load CH after neutralization of the actuating means 14 making the plate 13 fixed.

Depending on the desired packaging rates, it is also possible to make use of a carriage with a relative rotational movement opposite to that of the load plate.

Claims (12)

1. A machine for packaging a load (CH) by means of a film (12) made of flexible plastic material, comprising:

   - a rotating table (13) supporting the load (CH),

   - means for supporting a storage reel (11) of the film,

   - means (14) for actuating the table (13) in rotation,

   - a device (15) for multidirectional guiding of the film to cover the side face (16) and the horizontal top face (17) of the load (CH) without discontinuity by stretch wrapping, said device being fitted between the reel (11) and the rotating table (13) and comprising means for swivelling around a pivoting axis (22) between a horizontal position and a vertical position, and means for translational movement between a lowered position and a raised position separated from one another by a vertical travel that is adjustable according to the height of the load (CH),

   characterized in that the multidirectional guiding device (15) forms an assembly comprising a pair of guide rollers (21) between which the film runs, and an inclined countershaft device (28).
2. The packaging machine according to claim 1, characterized in that the film storage reel (11) and the multidirectional guiding device (15) are mounted on a moving carriage (CM) constituting said translational movement means.
3. The packaging machine according to claim 1, characterized in that the film storage reel (11) is a fixed-axis reel and is associated with an accumulator device (25) placed before the countershaft device (28).
4. The packaging machine according to claim 3, characterized in that the accumulator device (25) and the countershaft device (28) are mobile so as to perform spiral stretch wrapping around the load (CH).
5. The packaging machine according to one of the foregoing claims, using a stretchable film, characterized in that the film (12) is wound on the reel (11) in a pre-stretched state.
6. The packaging machine according to one of claims 1 to 4, using a stretchable film, characterized in that a pre-stretching device of the film (12) is arranged on output from the reel (11) and comprises a pair of motor-driven or non motor-driven rollers (26) enabling the film to be unwound on the downline side at a greater speed that that of the upline side.
7. The packaging machine according to one of claims 1 to 4, using a stretchable film, characterized in that a pre-stretching device of the film (12) is associated with the multidirectional guiding device (15).
8. The packaging machine according to one of the foregoing claims, characterized in that the multidirectional guiding device (15) comprises a pair of non motor-driven rollers (21) between which the film (12) runs.
9. The packaging machine according to one of the foregoing claims, characterized in that the countershaft device (28) is inclined at 45°, the reel (11) extending in a horizontal plane with respect to the ground.
10. The packaging machine according to one of claims 1 to 8, characterized in that the reel (11) extends vertically in a parallel direction to the axis of rotation of the table (13).
11. The packaging machine according to claim 2 or 3, characterized in that the carriage (CM) is animated with a rotation movement around the load (CH) after the actuating means 14 have been neutralized in rotation.
12. The packaging machine according to claim 2 or 3, characterized in that the carriage (CM) is animated with a relative reverse rotation movement with respect to that of the table (13) of the load (CH).

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