EP0000851A1 - Automatic machine for cutting a thermoplastic tube in parts and for applying sleeves around containers - Google Patents

Abstract

Automatic machine for cutting thermoplastic sheath and fitting sleeves around containers. The machine essentially comprises, arranged on a frame: a) means for supplying plastic sheath in flattened form and then for conveying the continuous strip under predetermined tension conditions; b) at least in a vertical assembly (3) for cutting the sheath and supplying sections or sleeves, this assembly comprising from top to bottom, arranged around a hollow mandrel with microperforations on its periphery and on which the sheath is engaged continues: - means for removing the two folds of the flat sheath; - means for cutting the sheath; stepped means making it possible both to maintain the mandrel in a vertical position and to automatically adjust the height and cutting rate; - Means for guiding and expelling the sleeves down the mandrel; these sleeves then being deposited automatically around containers to be coated circulating on a conveyor (4) provided with means (5) for hot shrinking of said sleeves, of a type known per se.

Description

The present invention relates to the field of making sheath sections of heat-shrinkable plastic and intended to be placed and then shrunk hot around containers. It relates more particularly to a new apparatus allowing the continuous production, at high speed, of such sections or sleeves from a continuous strip of flat sheath as well as the conformation of these sleeves to the types of containers to be coated and then their automatic laying around of these containers.

It is now well known to provide containers such as bottles, aerosol cans, flasks, cans and the like, made of various materials, with a protective sleeve or sheath made of shrinkable plastic. This sleeve is placed relatively loosely around the container and, after heating to cause the plastic to shrink, it must conform perfectly to the outline of the container. Receptacles are thus produced provided with sheaths, generally printed, in transparent thermoplastic material or in porous or cellular plastic material.

les manchons obtenus, empilés horizontalement ou verticalement gasin, servent à alimenter une machine permettant d'extraire individuellement les menchons puis ds les ouvrir à la conformation désirée et de les déposer autour des réceptacles à revêtir qui circulent sur un convoyeur,. l''habillage étant ensuite soumis à une thermorétraction (voir par exemple le brevet français N°76.05033 du 24 Février 1976 et ses certificats d'addition N°76.33691, 77.00209 et 77.19565).Many operating steps are necessary to pass from the thin plastic sheet (for example polyvinyl chloride), made heat shrinkable, to the receptacle provided with its decorated covering. These steps must be automated to achieve adequate industrial profitability. According to the technique most commonly used so far, the plastic film is made from a continuous sheath or sheath and then sections of sheath are cut to the appropriate dimensions and

the sleeves obtained, stacked horizontally or vertically gasin, are used to feed a machine making it possible to individually extract the lugs then to open them to the desired conformation and to deposit them around the receptacles to be coated which circulate on a conveyor. the covering then being subjected to heat shrinking (see for example French patent N ° 76.05033 of February 24, 1976 and its certificates of addition N ° 76.33691, 77.00209 and 77.19565).

This process is certainly satisfactory, but the apparatus for implementing the sleeves is of a fairly delicate adjustment, which affects its reliability. On the other hand, the production rates are relatively limited due to the complexity of the sleeve opening operations. Finally, the presence of the two fold lines of the sleeves deposited on the containers sometimes creates difficulties during the final heat-shrinking operation.

The object of the invention is to remedy these various drawbacks and is aimed at the production and fitting, at high speed, of sleeves already having the general conformation of the containers to be coated. To this end, it proposes an automatic apparatus which directly uses as raw material. the continuous flat sheath of plastic film and not of the stacks of sheath sections and which performs the series of operations of: shaping, cutting, guiding and fitting of the sleeve, according to a vertical line overhanging the series of receptacles which pass on a conveyor .

• a) des moyens d'alimentation en gaine plastique sous forme aplatie puis de convoyage de la bande continue dans des conditions de tension prédéterminées ;
• b) au moins un ensemble vertical de découpe de la gaine et de fourniture de tronçons ou manchons, cet ensemble comprenant de haut en bas, disposés autour d'un mandrin creux sur lequel est engagée la gaine continue ;
  • des moyens de suppression des deux plis de la gaine plate
  • - des moyens de découpe de la gaine ;
  • - des moyens étagés permettant à la fois de maintenir le mandrin en position werticale et de régler automatiquement les hauteur et cadence de coupe ;
  • - des moyens de guidage et d'expulsion des manchons vers le bas du mandrin des anchans étant déposés ensuite automatiquement autour de récipients à revêtir circulant sur un convoyeur muni de moyens de rétraction à chaud, de type connu en soi.

The new machine according to the invention is characterized in that it essentially comprises, arranged on a frame:

• a) means for supplying plastic sheath in flattened form and then for conveying the continuous strip under predetermined tension conditions;
• b) at least one vertical assembly for cutting the sheath and for supplying sections or sleeves, this assembly comprising from top to bottom, arranged around a hollow mandrel on which the continuous sheath is engaged;
  • means for removing the two folds of the flat sheath
  • - means for cutting the sheath;
  • - stepped means making it possible both to maintain the mandrel in the wertical position and to automatically adjust the height and cutting rate;
  • means for guiding and expelling the sleeves down the mandrel of the anchans then being automatically deposited around containers to be coated circulating on a conveyor provided heat shrinking means, of a type known per se.

According to one characteristic, the supply of flat sheath of the vertical assembly designated by b) is made by means of a closed package containing one or more sheath coils and provided with a horizontal slot allowing passage to the continuous strip. This strip, first subjected to strong traction is then released to allow subsequent adjustment of a predetermined cutting length and then it is again stretched over said vertical assembly.

According to another characteristic, all of the operations carried out on the sheath are carried out around a hollow carrier mandrel whose saction corresponds to the configuration desired for the final sleeve. This mandrel is carried by horizontal platforms delimiting several stages and provided with retractable lugs intended to engage in grooves provided on the mandrel.

According to an alternative embodiment, the thermo-plastic flat sheath is subjected to a precut operation before being engaged around the tapered upper part of the hollow mandrel. This operation, which can be carried out for example by means of a sawtooth blade penetrating into a counterpart made of rubber, allows a sharper and faster cut to be obtained subsequently.

The means of unfolding the sheath, just after the engagement of the latter around the mandrel, are constituted by jaws heated by any known means (electric, hot air, infrared, etc.) and whose contact time with the sheath on the mandrel is programmed in sequence with the cut and according to the temperature (generally between 70 and 120 ° C). These jaws can be controlled by any known means with an alternative function.

The means for cutting the sheath into sections or sleeves can advantageously be constituted by a rotary device provided with horizontal blades, for example two which penetrate into the sheath when they are already in rotation. However, other equivalent cutting systems, such as a device, with sharp jaws, cutting ring or the like, can of course be implemented. According to an alternative embodiment, it is also possible to provide, associated with the straight cut system of the sheath, a microperforation device intended to create a pre-cut line for obtaining sleeves of special type.

The steps which follow the cutting means are preferably three in number and essentially have the function of ensuring the lift and the centering of the mandrel during the cutting of the sheath then the descent and expulsion of the sleeves. The actions of these different levels are carried out in sequence, in particular by means of a central camshaft, in such a way that there are always, during the running of the machine, two open levels (that is to say released from the mandrel) and a closed level (platform blocking the mandrel) or vice versa.

The means for guiding the sheath on the mandrel are constituted on the one hand by rollers or rollers with alternative control and on the other hand by lug chains controlled by the camshaft. In addition, according to an important characteristic of the invention, the descent of the cut sheath section then its expulsion at the bottom of the mandrel are facilitated by sending, within this hollow mandrel and provided with microperforations preferably oriented downward , air or any other slightly pressurized fluid. This injection of fluid is triggered automatically after the cutting operation and is advantageously carried out at two points on the hollow mandrel, under different pressures.

All of the machine's components are placed on a frame provided with a series of disc-type clutch-brakes (or equivalent) driven alternately by chain pulleys or the like and which are actuated by a single motor or motor-variator. . According to a characteristic of the invention, this frame can support several cutting assemblies designated above by b) for example two, three or more. Thus, as will be seen below in more detail, the removal of the sleeves around the containers can be done continuously and at high speed during the movement of the containers on their conveyor.

• Fig.1 : une vue générale de face des principaux organes d'une machine selon 1'invention ;
• Fig. 2 : une vue de l'arrière de cette machine ;
• Fig. 3 : un ensemble comprenant une machine de pose de l'invention, associée à un convoyeur en continu de récipients et à un dispositif de rétraction à chaud des manchons après leur pose autour des récipients ;
• Fig.4 : un mode de mise en tension et relâchement de la gaine thermoplastique servant à l'alimenter l'ensemble verticale de découpe, transfert et pose des manchons ou tronçons de gaine ;
• Fig. 5 : un mode de maintien du mandrin central par la plate-forme de l'un des étages de l'ensemble vertical ;
• Fig.6 : un mode d'entraînement par chaîne d'un manchon le long du mandrin central de chaque ensemble vertical ;
• Fig 7 : une vue de côté simplifiée, d'un ensemble vertical ol- lustrant de façon schématique les principaux éléments d'un ensemble vertical.

Other characteristics will become apparent during the following description, relating to a nonlimiting embodiment, illustrated by the appended schematic drawings which represent:

• Fig.1: a general front view of the main components of a machine according to the invention;
• Fig. 2: a view of the rear of this machine;
• Fig. 3: an assembly comprising a laying machine of the invention, associated with a continuous conveyor of containers and with a device for hot shrinking of the sleeves after their laying around the containers;
• Fig.4: a method of tensioning and loosening the thermoplastic sheath used to supply the vertical assembly for cutting, transfer and fitting sleeves or sections of sheath;
• Fig. 5: a method of holding the central mandrel by the platform of one of the stages of the vertical assembly;
• Fig. 6: a chain drive mode of a sleeve along the central mandrel of each vertical assembly;
• Fig 7: a simplified side view of a vertical assembly schematically illustrating the main elements of a vertical assembly.

As shown in FIGS. 1 and 2, the machine essentially comprises: a magazine 1 for supplying a flat sheath of thermoplastic film; a system 2 for winding and distributing this sheath; one or more vertical assemblies 3 (the machine shown contains three) intended for cutting the sheath then for guiding and laying the sheath sections around containers; finally a series of means for transmitting the movements of the various members as well as means for controlling the movements of transfer and opening-closing of the stages of each vertical assembly. As will be described in more detail below, the machine is installed above a conveyor 4 intended for the continuous feeding of the receptacles to be coated and provided with a device 5 for hot shrinking of the sleeves after their removal around each receptacle.

The magazine 1 is advantageously constituted by a parallelepedic box, for example made of cardboard, in which there are arranged vertically side by side, separated by spacers, for example two coils 6 of plastic sheath wound flat as obtained by welding. continuously from two close edges of a heat-shrinkable plastic film such as, for example, polyvinyl chloride. The sheath can, of course, be provided with any prints and decorations according to known methods. One coil is kept in reserve while the other is used to power the machine. The packaging is provided with a slot 7 and the sheath 8 follows, as can be seen in FIG. 4, a path along which it is subjected to different tensions. At the start, the flat sheath is strongly pulled in traction by the cylinders 9. then it is then released by means of a flexible interlocking system 10 passing in front of a photoelectric cell 11; a sheath reserve is thus created during the subsequent cutting operation and the cell makes it possible to re-tension the sheath in order to deliver a new length of section to the assembly 3. The drive of the continuous strip to the top of the assembly 3 takes place between series of rollers or rollers 12 driven by the motor 13. As will be seen later, this single motor controls the series of clutch-brakes provided for the operation of the moving parts of the machine, as well as the camshaft for controlling the elements of each vertical assembly.

When the thermoplastic sheath 8 passes over the upper part of the assemblies 3, it can be subjected, if desired, to a pre-cutting operation before being engaged around the tapered head of the hollow mandrel 14. This operation, which can be practiced, for example, using a sawtooth blade penetrating into a counterpart in rubber, .allows you to obtain a more frank and faster cut of the sheath in sections.

After its engagement, at the start of unwinding of the coil 6 around the head of the mandrel, the sheath 8 is subjected to operations of: unfolding, cutting, transfer and fitting of the sleeves around the receptacles to be dressed. all these operations being carried out in synchronism, as will be seen below, in each of the vertical assemblies generally designated by the number 3.

• - des mâchoires chauffantes 15 de déplissage de la gaine après l'enfilage de celle-ci sur l'extrémité supérieure du mandrin 14 ;
• - des galets de guidage 16 de la gaine ;
• - des disques 17 de dégagement de coupe en prise avec un dispositif de coupe 18, ces disques 17 engrenant sur les pignons 19 d'un arbre à came 20 ;
• - des galets 21 puis des chaînes 22 d'accompagnement vers le bas du tronçon de gaine déjà coupé ;
• - une première plate-forme 23 au niveau de laquelle on envoie au sein du mandrin 14 de l'air sous faible pression (canalisation 24) destiné à accompagner le transfert vers le bas du manchon sur coussin d'air ;
• - une deuxième plateforme 25 correspondant à l'envoi, par la canalisation 26, d'air sous pression plus forte pour assurer l'expulsion du manchon sur le récipient à recouvrir (flèche 27) ;
• - une troisième plate-forme 28; proche de l'extrémité inférieure du madrtn 14, qui se termine avantageusement par une coiffe tronconique 29 permettant de réaliser un parfait alignement du récipient sous le mandrin.
• - l'ensemble de transfert et les mouvements d'ouverture-fermeture des trois étages qui correspondent aux plate-formes (23,25,28) étant commandés par l'arbre à came 20 entrainé par le moteur 13 et dont les ensembles de pignons (19,29,30,31) sont en prise avec les divers organes précités qui travaillent autour du mandrin creux 14.

Each vertical assembly essentially comprises, arranged around the vertical hollow mandrel 14, a series of means formed from top to bottom by (see FIGS. 1 and 7):

• - Heating jaws 15 for unfolding the sheath after threading it on the upper end of the mandrel 14;
• - guide rollers 16 of the sheath;
• - Cutting clearance discs 17 engaged with a cutting device 18, these discs 17 meshing with the pinions 19 of a camshaft 20;
• - Rollers 21 then chains 22 accompanying down the already cut sheath section;
• - A first platform 23 at which is sent within the mandrel 14 air under low pressure (pipe 24) intended to accompany the downward transfer of the sleeve on the air cushion;
• - A second platform 25 corresponding to the sending, via the pipe 26, of air under higher pressure to ensure the expulsion of the sleeve on the container to be covered (arrow 27);
• - a third platform 28; near the lower end of the madrtn 14, which advantageously ends in a frustoconical cap 29 allowing perfect alignment of the container under the mandrel.
• - the transfer assembly and the opening-closing movements of the three stages which correspond to the platforms (23,25,28) being controlled by the camshaft 20 driven by the motor 13 and whose pinion assemblies (19,29,30,31) are engaged with the various aforementioned members which work around the hollow mandrel 14.

Of course, the power cable series and the accessory bodies have not been shown in the figures of the appended plates so as to improve clarity and facilitate understanding.

We will now resume below a more detailed description of certain essential members of a vertical assembly of the machine.

The mandrel 14 which can have any shape, for example cylindrical, is constituted by a hollow element, made of plastic, metal or alloy, the wall of which is provided with microperforations intended to let escape a flow of air or other blown fluid inside. This mandrel 14 is permanently maintained and adjusted in the vertical position by at least one of the platforms 23,25,28. For example, as can be seen in FIG. 5, a platform (example: 23) is provided with several studs 32, actuated by springs 33 or other means, these studs being received in a groove or groove 34 provided on the periphery of the mandrel 14. According to a variant, not shown in the figures, the mandrel can be held at least at one of the platforms 23,25,28 by a jaw adapting to an appropriate housing of the mandrel.

While the sheath is driven in its descent on the mandrel 14 by the rollers 16 actuated by the clutch-brake 35 connected to the camshaft, this sheath is subjected to unfolding by means of the heating jaws 15 formed, for example , by two metal half-shells internally coated with a plastic material (silicone rubber or the like) intended to avoid any possible local overheating. Thanks to their constitution, these two shells join together on the mandrel 14.

After unfolding, the sheath is subjected to the cut 18 for example using a rotary device with blades, designated by the number 18 in Figures 1 and 7, which is also driven by the motor 13 and whose blades penetrate in the film when they are already rotating. According to a particular embodiment, .on can be added to this cutting device a microperforation system intended, to create in a given area of the sheath an additional pre-cut line.

At the level of the cut and preferably just below or just above depending on whether the sheath is printed or not, a photoelectric cell (not shown in the figures) is installed which makes it possible to determine the appropriate length of each section of sheath.

As said above, the opening and closing functions of each of the stages delimited by the platforms (23,25,28) along the mandrel 14 are controlled by the various pinions of the camshaft 20. The downward transfer and expulsion of the sleeve (arrow 27) are facilitated ted by the pressurized air sent under two different pressure flow rates via lines 24 and 26. The third line 38 visible in Figure 1. is connected to the cylinder (not shown) which is used to supply the possible precut device capable of be installed above a set 3.

According to a characteristic of the invention, a chain 22 is provided on each side of the mandrel 14 provided with a lug or projecting finger 36 (see FIG. 6) and which, controlled by the camshaft 20, accompanies the progression of the sleeve 37 downwards, the movement of this chain being synchronized with the opening and closing operations of the stages.

The brief description of an embodiment of a machine as defined above will allow a better understanding of the invention.

When the sheath 8, possibly pre-cut, has just been threaded onto the mandrel 14 (start of the coil), the mandrel is held in position by closing the studs 32 provided on the platform 28 of the lower stage ( rest position). The platforms 23 and 25 are open while the platform 28 is closed; the roller systems 16 are set in motion to lower the sheath over the length of cut to be made. The electromagnet cell (not shown) causes the shutdown. of these rollers and controls the unfolding operation at 15, then initiates the cut at 18. The end of cut, detected by a counterfeiter, triggers the rotation of the rollers 21, 'of the camshaft 20 and the accompanying chains 22 of the sheath section. The camshaft rotates, closes the stage 23 and opens the stage 25. During this time, the chain 22 ensures the passage of the sheath section to the stage 25. The camshaft 20 continues to rotate then it ensures the closing of the stage 25 and the opening of the stage 28. The sheath section then continues its course until the lug chain 22 has expelled, with the support of the air pressure sent through the pipe 26, the sleeve outside the hollow mandrel 14. At this time, the lower stage 28 closes while the upper stage 23 opens and the cycle begins again in the order indicated above.

, Thanks to a machine with three heads (or vertical assemblies mentioned above), as illustrated in FIGS. 1, 2 and 3, it is possible to obtain a laying rate of approximately 120 sleeves per minute around receptacles to be coated.

In practice, as illustrated in FIG. 3, the machine is installed above a conveyor 4 intended for the continuous feeding of the containers to be sleeved. One can use for example for this purpose the conveyor described in the French patent N ° 75.30896 of October 9, 1975 (and Addition Certificates N ° 75.36299, 76.08851 and 76.39546). Such an endless belt conveyor is provided with a heating tunnel 5 intended to heat shrink the sleeves around the containers brought by the conveyor and covered by a vertical assembly 3.

Of course, all other bodies with equivalent function can be substituted for those described in the above non-limiting example without departing from the scope of the present invention.

Claims (9)

1. Machine intended for automatic cutting and at programmed rates of heat-shrinkable plastic sheaths into sections or sleeves suitable for being deposited and then shrunk hot around containers, the machine being characterized in that it essentially comprises, arranged on a frame : a) means for supplying plastic sheath in flattened form and then for conveying the continuous strip under predetermined tension conditions; b) at least one vertical assembly for cutting the sheath and for supplying sections or sleeves, this assembly comprising from top to bottom, arranged around a hollow mandrel with microperforations on its periphery and on which the continuous sheath is engaged: - means for removing the two folds of the flat sheath; - means for cutting the sheath;
-staged means allowing both to keep the mandrel in a vertical position and to automatically adjust the height and cutting rate; - Means for guiding and expelling the sleeves down the mandrel;
these sleeves then being deposited automatically around containers to be coated circulating on a conveyor provided with means for hot shrinking of said sleeves, of a type known per se. 2. Machine according to claim 1, characterized in that the means for supplying the flat sheath are constituted by several coils enclosed in a package delivering the sheath by horizontal slots and in that the conveyance of the strip is carried out alternately under strong tension then under slackening with flexible interlocking system to allow the lengthening and the cutting of the section of sheath. 3. Machine according to claim 1, characterized in that the means for unfolding the sheath are constituted by heating jaws whose application time on the mandrel is programmed in sequence with the cutting of the sheath and is a function of the temperature of heating. 4. Machine according to claim 1, characterized in that the sheath cutting means are constituted by a rotary device has one or more blades..or knives, which engage on the sheath while they are already in rotation around the mandrel. 5. Machine according to claim 1, characterized in that said stepped means comprise platforms concentric with the mandrel and provided with retractable lugs intended to engage in provided grooves on the mandrel these platforms delimiting at least two stages for the height control of the cut / cut, the transfer to the bottom of the sleeve and its expulsion at the end of the mandrel. 6. Machine according to claim 1, characterized in that the means for guiding the sections on the mandrel and then for expelling down the mandrel are constituted by the combination of pebbles of pebbles, chains with pins accompanying the descent of each sleeve , and by sending pressurized fluid to at least one point of the hollow mandrel and within the latter provided with microperforations on its periphery. 7. Machine according to any one of claims 1 to 6, characterized in that the means for removing folds from the sheath, the cutting means and the guide-transfer-expulsion means of the sheath sections are controlled by a shaft. with central cam connected to series of pinions, this shaft ensuring synchronism between the successive openings and closings of the stages of said vertical assembly. 8. Machine according to claim 1, characterized in that the continuous flat sheath is subjected to a precut operation before its introduction around the mandrel of a vertical assembly. 9. Machine according to claim 1, characterized in that the lower end of the hollow mandrel is provided with a cap of substantially frustoconical shape allowing perfect alignment of the mandrel aved the container to coat the sleeve.

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