FR2986509A1 - Equipment for bundling batch of bottles in bundling machine, has perforation device to receive and transmit tape of heat shrinkable film to cutting device, where perforation device punches series of puncture holes in tape - Google Patents

Abstract

The equipment (8) has a tape reeler (11) for unwinding a tape (12) of a heat shrinkable film, and a cutting device (13) for periodically cutting the tape to deliver a series of sheets (9) of the heat shrinkable film. A perforation device (14) is arranged to receive the tape of the heat shrinkable film from the tape reeler and to transmit the tape to the cutting device, where the perforation device punches a series of puncture holes in the tape such that the holes are arranged along a precut line in the tape. An independent claim is also included for a bundling method.

Description

Equipment and process for shrinkwrapper. FIELD OF THE INVENTION: The invention relates to the field of wrapping equipment and methods, which use a heat-shrinkable film web to coat an object or batch of objects, such as bottles, with a sheet of this heat-shrinkable film. , and form, for example a pack of bottles.

STATE OF THE ART: Application FR 2 823 190 discloses a shrinkwrapper which makes it possible to surround a batch of objects with a heat-shrinkable film. The objects can be of type packs of bottles for example. The film can then be heat-shrunk around the batch of objects by passing through a heat-shrink tunnel. The heat-shrinkable film used in shrinkwrappers is generally chosen to allow the batch of objects to be caught and carried by the heat-shrunk film, without the film tears. Thus, the heat-shrinkable film is a cheap overpack around the object or batch of objects. The end user of the object package often needs to separate the objects from each other for use individually. The resistance of the heat shrinkable film to tearing, necessary to transport the pack of bottles, makes it often necessary to have scissors or cutting blade to remove the overpack. There is a need to simplify shrinkage of the heat shrunk film around an object or a lot of objects. However, this improvement must be compatible with high speeds of movement of the heat-shrinkable film in the shrinkwrappers. In addition, it is necessary to avoid heating the heat-shrinkable film so as not to initiate local heat shrink, and this so that the heat-shrinkable film strip remains locally flat during the entire process of topping the batch of objects by the film strip.

OBJECT AND SUMMARY OF THE INVENTION: The invention provides an equipment and a method for shrinkwrapper that remedy at least one of the aforementioned drawbacks.

An object of the invention is to provide an equipment and a method for shrinkwrapper that facilitate the extraction of the heat-shrunk film around an object or a lot of objects, and this while not causing the band to fold. of film before heat shrinking.

According to one embodiment, the wrapping machine equipment comprises: - a strip feeder designed to unwind a strip of heat-shrinkable film, - a cutting device designed to periodically cut the film strip in order to deliver a series of sheets of film, and - a perforating device arranged to receive the heat-shrinkable film web of the tape feeder and to transmit said non-cut tape to the cutter; the perforating device being adapted to perforate a series of holes in the film web, which holes are arranged along a precut line. Advantageously, the perforation device 30 comprises a means for guiding the heat shrinkable film strip defining a running surface and a direction of travel of the film in the perforating device. Advantageously, the precut line is perpendicular to the direction of travel.

According to one embodiment, the perforation device comprises a first knife having a plurality of teeth, and movable between a first withdrawal position and a first perforation position in which a tip of each of the teeth of the first knife protrudes from one side. the scrolling surface opposite the side where the first knife is in the retracted position. It is understood that the fact that the perforation is done by a knife, makes it possible not to heat locally the strip of film not yet heat shrunk. This allows the filmstrip to remain locally flat and is compatible with subsequent filmstrip processing processes in known shrinkwrappers, such as cutting, injection, or wrapping the film around the batch of objects. . Advantageously, the perforation device further comprises a first positioned anvil, when the knife reaches its perforation position, to retain the film strip. The anvil makes it possible to cut the film cleanly. This avoids mechanically stretching the film around the perforations. This preserves the locally flat shape of the filmstrip. According to one embodiment, the perforation device comprises a second knife having a plurality of teeth, the second knife being movable between a second retracted position and a second perforation position, the first retracted position of the first knife and the second position. removing the second knife being located on either side of the scrolling surface. This makes it possible to make two precut lines side by side. This facilitates the simultaneous tearing of the two precut lines. In a variant, the two knives act on adjacent portions of the film. This allows one knife to serve as an anvil to the other knife. This variant of perforation device is suitable for a heat-shrinkable film which is either tight or relatively resistant in bending. Advantageously, the precut line of the first knife and the section line of the second knife each consist of a succession of cut segments aligned and separated from each other by film. The precut line of the first knife and the precut line of the second knife are separated by a distance greater than three times the separation distance between two successive segments of the same cutting line. This particular profile of dashed precut lines is easy to tear. Indeed, during tearing, the film is subjected to a high stress concentration at the end of a pre-cut segment. The fact that the film strip between the two precut lines is much more resistant than the portion of film between two successive segments makes it is this portion that tears in priority. Thus, the two pre-cut lines tear together progressively. Advantageously, successive segments of the same cutting line are separated by a distance of between half and twice the length of the cut segments. According to one embodiment, at least the first knife is rotatable about a first axis parallel to the scroll surface and perpendicular to the scroll direction. Preferably, the perforating device comprises a single knife movable about the first axis. According to one embodiment, the second knife is rotatable about a second axis of rotation parallel to the first axis of rotation. According to one embodiment, the perforation device comprises means of synchronization in opposite directions of the rotation of the first and second knives, which second knife is angularly offset relative to the first knife by an angle of between 5 ° and 30 °. preferably between 10 ° and 20 °, in particular between 10 ° and 15 °. According to one embodiment, the second knife is fixed on a second roller. The second roll has a second shoulder emerging on a cylindrical surface of the second roll by an edge parallel to the second axis of rotation. Said edge is disposed opposite and radially beyond the tips of the teeth of the first knife when the teeth of the first knife cross the scroll surface. The second shoulder is further arranged to receive the teeth of the first knife and for the portion of the cylindrical surface adjacent to the ridge to serve as an anvil support for the film strip. This allows for an anvil that stays close to the tip of the knife teeth while the film continues to scroll. Thus, the whole knife and anvil advance with the film. This allows the filmstrip to be punctured while traveling at a high speed. Advantageously, the first knife is fixed on a first roller, which first roller has a first shoulder opening on a cylindrical surface of the first roller by an edge parallel to the first axis of rotation. Said edge is disposed opposite and radially beyond the tips of the teeth of the first knife when the teeth of the first knife cross the scroll surface. The second shoulder is further arranged to receive the teeth of the first knife and for the portion of the cylindrical surface adjacent to the ridge to serve as an anvil support for the film strip. Alternatively, the first and second rollers are of the same diameter, adapted to grip the film web, at least near the point where the tips of the teeth are trying to puncture the film web. This prevents the film strip slips on the support anvil and deforms without perforating to follow the tips of the teeth into the shoulder. This pinching of the film at the time of perforation makes this perforation more reliable or more compatible with thinner film strips. Advantageously, the guide means is constituted by two auxiliary rollers, free in rotation, one upstream of the first knife, the other downstream of the first knife. Advantageously, the two auxiliary rollers are arranged on each side of the scrolling surface. Advantageously, the perforating device is synchronized with the cutting device so that the pre-cut line of a given film sheet is remote from the sections made by the cutting device. Advantageously, the film sheets are each intended to be subjected to a layering operation and then to a heat-shrinking operation around an object. The precut line is such that the perforated heat-shrinkable film sheet is able to withstand tableting and heat-shrinking operations and to be torn after these operations along said precut line. According to another aspect, the invention also relates to a wrapping process comprising: a step of unwinding a strip of heat-shrinkable film; a step of periodic cutting of the strip of film to deliver a series of sheets film, and - a step of perforating the film strip by holes along a precut line. Advantageously, the aforementioned method comprises a step of lapping and heat shrinking of the film sheet around an object, the precut line being able to withstand the operations of lapping and heat shrink and to be torn after these operations. Advantageously, the heat-shrinkable film used by the process is a low density polyethylene film. Advantageously, the low density polyethylene film may be of the linear type or of the mixed root and linear type. Advantageously, the film may be 90 microns thick. Advantageously, the film may have a resistance at 3% elongation greater than 120 MPa. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood by studying the detailed description of some embodiments taken by way of non-limiting examples and illustrated by the appended drawings in which: FIG. 1 is a side view of FIG. a shrinkwrapper using equipment of the invention; Figure 2 is a perspective view illustrating a first embodiment of the product obtained by the wrapping process; FIG. 3 is a perspective view of a first embodiment of the perforation device; Fig. 4a is a detail on the plane IV-IVa of Fig. 3 with the knife and anvil illustrating a retracted position and a perforation position; - Figure 4b is a cross section along the plane IVb-IVb of Figure 4a; Figure 5 is a sectional view of a second embodiment of the perforating device; - Figure 6 is a partial sectional view illustrating a third embodiment of the perforating device; and Figure 7 is a partial view illustrating a fourth embodiment of the perforation device.

DETAILED DESCRIPTION: As illustrated in FIG. 1, a shrinkwrapper 1 has a plan 2 for conveying a lot 3 of objects 4 such as bottles. The shrinkwrapper 1 comprises successively along the conveying plane 2, a conveyor 5 supply, a conveyor 6 topping and a tunnel 7 heat shrink. The succession of the above elements defines a conveying direction 2a of the shrinkwrapper 1. The shrinkwrapper 1 comprises, located below the conveying plane 2, an equipment 8 designed to provide a series of sheets 9 of heat-shrinkable film in a space 10 separating the supply conveyor 5 from the conveyor 6 of the topping. The equipment 8 comprises a reel 11 of a strip 12 of heat-shrinkable film, a device 13 for cutting the strip 12 of film and a perforation device 14 interposed between the tape feeder 11 and the cutting device 13 in the scrolling direction of the film strip 12. In other words, the perforation device 14 is arranged to receive the strip 12 of heat-shrinkable film 25 of the tape feeder 11 and to transmit the said non-sectioned strip 12 to the cutting device 13. The web feeder 11 may comprise a spool 16 mounted on driving rollers 16a. It may advantageously comprise a buffer device arranged to allow an acceleration of the speed of supplying the sheets of film without the coil having to present the same profile of unwinding speed. The cutting device 13 comprises a pair of driving rollers 18 and a knife 19 disposed downstream of the pair of driving rollers 18. Alternatively, the cutting device 13 may comprise a second pair of drive rollers disposed immediately downstream of the knife 19, to tension the strip 12 of film before cutting it. In the variant illustrated in Figure 1, the perforation device 14 is disposed between the buffer device 17 and the cutting device 13. In another variant, the perforation device 14 may be disposed between the coil 16 and the buffer device 17.

The piercing device 14 comprises a first roll 20, equipped with a first knife 21, a second roll 22, equipped with a second knife 23 and two auxiliary rollers 24. The auxiliary rollers 24 define a direction of travel 24a along a surface 25 for guiding the film web 12 placed between the rollers 20 and 22. Advantageously, axes 21a, 23a of rotation of the first and second knives 21, 23 as well as the axes of the two auxiliary rollers 24 are parallel to the guide surface.

Advantageously, the guide surface 25 is a plane passing between the first roller 20 and the second roller 22, for example on the two rollers 24. Advantageously, the axes 21a, 23a and the axes of the auxiliary rolls 24 are substantially perpendicular to a 24a direction of travel of the film strip 12 in the perforation device 14. Advantageously but not mandatory, the axes 21a, 23a of the first and second knives 21, 23 and / or the axes of the auxiliary rollers 24 are parallel to the plane 2 of conveying. In the variant illustrated in FIG. 1, the two auxiliary rollers 24 are disposed on either side of the guide surface. This may facilitate the implantation of the perforation device 14. In another variant, the auxiliary rollers 24 are arranged on the same side of the guide surface. This may facilitate the insertion of the film strip 12 through the piercing device 14. The sheet 9 of film is introduced into the slot-shaped space 10, just as the batch 3 of objects 4 leaves the conveyor 5 supply. Lot 3 straddles the slot 10 and pinches by its weight the sheet 9 of film between the lot 3 and a carpet of the conveyor 6 of topping. A cycling device then drives the sheet 9 of film around the batch 3 during its conveyance by the conveyor 6 of topping. During this conveying, the batch 3 of objects 4 comprises a front side 26a, a rear side 26b, an upper side 26d and a bottom 26c, which sides are all covered with the film sheet 9 before entering the tunnel 7 heat shrink. On the other hand, two side faces 26e and 26f of lot 3 are not completely covered with film sheet 9. As illustrated in FIG. 2, the piercing device 14 is arranged to perforate a series of segment-shaped holes 29 aligned along a pre-cut line. The precut line 15 is perpendicular to the direction of movement 24a of the film strip 12 through the piercing device 14. Advantageously but not obligatorily, at least one precut line 15, where all the pre-cut lines 15 pass through the film strip 12 on either side and in the width direction of the film strip 12. In other words, said one or more precut lines extend from a lateral opening 27e facing the lateral side 26e to a lateral opening facing the lateral side 26f of the batch 3. Advantageously, the perforating device 14 makes it possible to two precut lines 15, side by side, and separated longitudinally by a distance "1f" along the direction of travel 24a. The distance between the two precut lines 15 defines a tongue 28.

Advantageously, each of the precut lines 15 comprises a succession of perforated segments 29 with a length "d" along the pre-cut line 15. Each of the segments 29 is separated by a film bridge 30 over a length "s". Advantageously, 3s. This allows the user to easily detach the entire length of the film tongue 28 and thereby cut the heat shrunk film surrounding the batch 3.

In the variant illustrated in FIG. 3, the piercing device 14 is equipped with a single knife 21, fitted into the first roll 20. The first and second rollers 20, 22 are substantially contiguous with each other. to pinch, hold and drag the film strip 12. The first and second rollers 20, 22 are of the same diameter, symmetrical axes, and parallel to the guide plane defined by the auxiliary rollers 24. This variant comprises a non-illustrated means for synchronizing the rotation of the two rollers 20, 22, which may be of the mechanical type for example using belts or gears, or be of electronic type, for example using controlled motors. The second roller 22 comprises a groove 31, for example U-shaped or V-shaped, arranged to receive the knife 21 during rotation. The groove 31 opens into a surface 32 outside the roller 22 which is substantially cylindrical. In the example shown, the groove 31 comprises two shoulders 31a opening on the cylindrical surface 32 by an edge. One of the shoulders is connected to a portion 32a of the surface 32, the other shoulder is connected to a portion 32b of the surface 32. The portions 32a, 32b are located on either side of the groove 31 and serve Anvils keeping the strip 12 of film substantially close to the guide plane 25 while the knife 21 penetrates into the groove 31. This holding promotes the perforation of the strip 12 of film by the knife 21 and makes it possible to control the depth of penetration of the knife 21 through the film strip 12. In a variant, the roll 22 may comprise a single shoulder 31a comprising a single side opening on the cylindrical surface 32 at a location close to the knife 21 in the perforation position. The portion 32a of the cylindrical surface 32 constitutes an anvil for holding the film strip 12 in position. Knife 21 comprises a plurality of teeth 33 each having a tip 33a. The teeth 33 are illustrated in triangular shape but may have any shape adapted to perforate heat-shrinkable film. Advantageously, the teeth 33 are distributed along a plane passing through the axis 21a of rotation of the knife 21 or in a plane parallel to this axis. This makes it possible to obtain a precut line 15 which is perpendicular to the running direction 24a of the film strip 12 between the two auxiliary guide rollers 24. Advantageously, but not obligatory, the tips 33a of the teeth 33 are at the same radial distance from the axis 21a of rotation of the blade 21. This allows the knife 21 to move from a retracted position illustrated in FIG. in dashed lines in FIG. 4a, to a perforation position illustrated in full lines in FIGS. 4a and 4b. The distance, perpendicular to the guide plane between the tip 33a and the anvil portions 32a, 32b, defines the punching distance which is precisely controlled so that the strip 12 of film is not completely cut by the knife 21. In other words, the piercing device 14 is designed so that there is a film bridge 30 between two teeth 33 when the knife 21 is in the piercing position.

In the embodiment illustrated in FIG. 5, the perforation device 14 comprises two knives 21, 23. The first knife 21 is fitted into a first roll 34, movable about the axis 21a of rotation of the first knife 21. The second knife 23 is fitted into a second roller 35 rotatable about the axis 23a of rotation of the second knife 23. The first and second rollers 34, 35 have their rotations synchronized by gear wheels 36 fixed to said rollers. The first roller 34 comprises a first groove 37 arranged to receive the second knife 23. The second roller 35 comprises a second groove 38 arranged to receive the first knife 21. The rotations of the two rollers 34, 35 are out of phase with each other. an angle "A" between the two knives 21, 23. The angle "A" angular offset is between 5 ° and 30 °, preferably between 10 ° and 20 °, in particular between 10 ° and 15 °. Each of the rollers 34, 35 has a cylindrical surface 39 extending over a portion 39a between the knife 21, 23 and the groove 37, 38, on a portion 39b located on one side of the knife 21, 23 opposite the groove 37 , 38 and extending in the vicinity of the knife 21, 23, and on a portion 39c located on one side of the groove 37, 38, opposite the knife 21, 23 and extending in the vicinity of said groove 37, 38. The portions 39a and 39c extend over an angular sector which may be between 5 ° and 30 °. Thus, the strip 12 of film is kept pinched and driven while the assemblies formed by the portions 39a, 39b, 39c of each of the rollers 34, 35 roll against each other. Advantageously, the rollers 34, 35 have an outer surface which is radially recessed out of the angular sectors along which the portions 39a, 39b, 39c extend. This makes it possible to pinch the film only when punching the two precut lines 15 illustrated in FIG.

The variant illustrated in Figure 6 corresponds to the perforation device 14 illustrated in Figure 1. The rollers 20, 22 do not pinch the strip 12 of film. The spokes of the rollers 20 and 22 are small enough so that the tips 33a of the knives 21, 23 are not impeded in their rotation by the opposing roll. There is no receiving groove. The rollers 20, 22 do not participate in maintaining the position of the film strip 12 during the perforation. The holding in position of the film strip 12 during the perforation by the second knife 23 is provided by the first knife 21. The first and second knives 21, 23 are angularly close enough to one another so that the perforation force of one of the knives is very close in intensity and opposite direction to the perforation force exerted by the other knife on the strip 12 of film. The bending stiffness of the film strip 12 and / or the tension of the strip 12 keeps the film substantially parallel to the time plane between the each of the angular knives between the non-zero and the lower guide despite the phase shift perforation forces 21, 23 For this purpose, exerted by the offset knives 21, 23 is preferably 20 °, preferably less than 15 °, especially less than 10 °. The angular offset between the knives 21, 23 may also be less than 5 ° if the radius of the path 33b of the tip 33a is sufficient so that the first and second knives 21, 23 can be interposed without touching.

This embodiment is suitable for heat-shrinkable films having sufficient flexural stiffness, or for shrink wrappers 1 guaranteeing a minimum tension of the film strip 12. Advantageously, the film used is a low density polyethylene material of linear and / or root type.

As illustrated in FIG. 7, a perforating device 50 comprises a single knife 51 fitted into a first roll 52, a second roll 53 serving as an anvil and comprising a groove 54 and a third roll 55 arranged for pressing the film strip 12 on the second roller 53. Thus, a portion 56a of the strip 12 of film upstream of the precut line 15 (with respect to a direction 57 of travel of the strip 12) is pinched by the second and third rollers 53, 55 .

A portion 56b of the film strip 12 downstream of the precut line 15 is pinched by the first and second rollers 52, 53. The three rollers 52, 53, 55 define a guide surface 58 of the film strip 12 . The surface 58 is curved here. The perforation device 50 is suitable for a film of low stiffness and / or for films whose tension during scrolling can be temporarily zero.

Claims (16)

REVENDICATIONS1. Equipment (8) for a shrinkwrapper (1) comprising a web feeder (11) adapted to unwind a strip (12) of heat-shrinkable film and a cutter (13) adapted to periodically cut the strip (12) of film to deliver a series of sheets (9) of film, characterized in that it comprises a perforation device (14, 50) arranged to receive the band (12) of heat-shrinkable film of the tape feeder (11) and to transmit said tape (12) uncut to the cutting device (13); the perforation device (14, 50) being adapted to perforate a series of holes (29) in the film web (12), which holes are arranged along a precut line (15). Equipment according to claim 1, wherein the perforation device (14, 50) comprises means for guiding the heat-shrinkable film web, which guide means defines a scroll surface (25, 58) and a direction ( 24a, 57) of the film in the perforating device. 3. Equipment according to claim 2, wherein the precut line (15) is perpendicular to the direction (24a, 57) of scrolling. 25 Equipment according to claim 2 or 3, wherein the perforation device (14, 50) comprises a first knife (21, 51) having a plurality of teeth (33), and movable between a first withdrawal position and a first perforation position in which a tip (33a) of each of the teeth (33) of the first knife protrudes from one side of the running surface (25, 58) opposite the side where the first knife (21, 51) is located in the retracted position. Equipment according to claim 4, wherein the perforating device further comprises a first anvil (32a, 32b, 39a, 39b, 39c, 58) positioned, when the knife reaches its perforation position, to retain the band (12). ) of movie. 6. Equipment according to claim 4 or 5, wherein the perforation device (14) comprises a second knife (23) having a plurality of teeth (33), the second knife being movable between a second withdrawal position and a second position. perforation, the first removal position of the first knife and the second removal position of the second knife being located on either side of the surface (25) for guiding. 7. Equipment according to claim 6, wherein the precut line (15) of the first knife (21) and the line (15) of the second cutting knife (23) are each constituted by a succession of segments (29) cut aligned and separated from each other by film 20 (30), and wherein the precut line of the first knife (21) and the precut line of the second knife (23) are separated by a distance (0 greater than three the separation distance (s) between two successive segments (29) of one and the same cutting line (15), the successive segments (29) of one and the same cutting line (15) preferably being separated from one another. distance (s) between half and twice the length (d) of the cut segments (29). 8. Equipment according to one of claims 4 to 7, wherein at least the first knife (21, 51) is rotatable about a first axis (21a) of rotation, parallel to the surface (25, 58). ) and perpendicular to the direction (24a, 57) of scrolling. 9. Equipment according to claims 6 and 8 as a whole, wherein the second knife (23) is rotatable about a second axis (23a) of rotation parallel to the first axis (21a) of rotation. 10. Equipment according to claim 9, wherein the perforation device comprises means (36) for synchronization in opposite directions of the rotation of the first and second knives (21, 23), which second knife is angularly offset relative to the first knife. an angle (A) between 5 ° and 30 °, preferably between 10 ° and 20 °, in particular between 10 ° and 15 °. 11. Equipment according to claim 9 or 10, wherein the second knife (23) is fixed on a second roller (22, 35), which second roller has a shoulder (31a, 38) opening on a surface (32, 39). cylindrical second roller, which shoulder is arranged opposite and radially beyond the tips (33a) of the teeth of the first knife (31) when the teeth (33) of the first knife (21) intersect the surface (25) guide ; said shoulder being further arranged to receive the teeth (33) of the first knife (21) and for the portion (32a, 39a, 39c) of the cylindrical surface (32) adjacent to the shoulder (31a, 38) to serve support anvil for the film strip (12). 25 12. Equipment according to one of claims 4 to 11, wherein the guide means is constituted by two rollers (24) auxiliary, free in rotation, one upstream of the first knife (21), the other downstream. the first knife (21); and preferably wherein the two auxiliary rollers (24) are disposed on each side of the guide surface (25). 13. Equipment according to one of the preceding claims, wherein the deperforation device (14, 50) is synchronized with the cutting device (13) so that the precut line (15) of a given film sheet is remote. sections made by the cutting device (13). 14. Equipment according to one of the preceding claims, wherein the sheets (9) of film are each intended to be subjected to a lapping operation and then to a heat-shrinking operation around an object, the line (15) pre-cut being such that the sheet (9) of perforated heat-shrinkable film is able to withstand the operations of lapping and heat-shrinking and to be torn after these operations along said precut line. 15. A method of wrapping comprising: a step of unwinding a heat-shrinkable film strip, a step of periodic cuts of the film strip to deliver a series of film sheets, characterized in that it comprises a perforation step 20 of the film strip through holes along a precut line. 16. The method of claim 15, comprising a step of lapping and heat shrinking of the film sheet around an object, the precut line 25 being able to withstand the operations of lapping and heat shrink and be torn after these operations. .