EP0048656A1 - Device for a machine opening, transferring and cutting thermoplastic sleeves and placing the sections around containers - Google Patents

Abstract

Vertical assembly with floating mandrel for a machine for making and positioning retractable sections around containers starting from a continuous flat sleeve made of plastic. The assembly comprises a cylindrical mandrel (2) equipped with a narrowing (2') into which penetrate, as means for supporting the mandrel, driving rollers (7, 7') in contact with idle rollers (8, 8') integral with the mandrel. The mandrel is also guided by series of upper (13) and lower (14) rollers. It is surmounted by a shaping element (1) which opens the sleeve to be dilated (16) and against which another series of centring rollers (15, 15') presses. The lower part of the mandrel (2) is hollow and comprises a piston (3) - impression (4) system intended to facilitate the positioning of the section in the axis of the container (5) to be covered. The cutting of the sleeve (16) into sections is ensured by the device (6).

Description

The present invention relates to the field of equipment intended for making sheath sections or sleeves from a flat sheath made of heat-shrinkable plastic and for laying these sleeves around containers. It especially relates to a device for opening, transferring sheath cutting and then fitting sleeves in an automatic machine supplied with a flat continuous sheath of heat-shrinkable plastic, whether or not printed.

It is known that numerous operational steps are necessary to pass, in the abovementioned technique, from the thin sheet of heat-shrinkable plastic material (for example polyvinyl chloride) and shaped in a flat sheath or continuous sheath, to the receptacle provided with its covering. , usually decorated.

Various machines have been described for automating these steps and it is particularly necessary to underline in this respect the apparatus which is the subject of the European patent published under the number 0.000.851 (deposit N ° 78 400 045.7). This apparatus comprises, around a hollow vertical mandrel, a set of stepped means making it possible to hold the mandrel in position, to automatically adjust the heights and cutting rates, to guide and expel the sleeves downwards and to ensure the laying around containers to be coated, circulating on a conveyor.

Such a machine is satisfactory and allows very good sleeving rates. However, it requires the use of a fairly large number of mechanical and electromechanical devices, the adjustment of which is delicate and which make the cost of the final apparatus relatively high.

The object of the invention is to propose a machine for making and installing vertical sleeves based on the same general principle as the above-mentioned apparatus, but of simpler construction and of more accessible price. It particularly relates, in such a machine, to improvements to the vertical assembly of the floating mandrel by means of both simplified and more effective means of supporting the mandrel and driving the sheath first flat then expanded, and finally transfer and install sleeves cut in this sheath.

• . un mandrin longiforme périphérique présentant ,sensiblement dans sa partie médiane, un rétrécissement/à l'intérieur duquel est fixée au moins une paire de roulements de contre-appui dont un secteur circulaire est en saillie du rétrécissement, le mandrin possédant en outre, dans sa partie inférieure creuse, un piston mobile à l'extrémité duquel est fixée une empreinte en creux destinée à venir coiffer le récipient à manchonner ;
• . un support ou conformateur fixé sur la tête du mandrin, de faible épaisseur, légèrement conique vers le bas et dont l'extrémité supérieure a une largeur légèrement inférieure à la largeur à plat de la gaine qui s'enfile sur ledit support avant de parvenir, sous forme dilatée, sur la tête du mandrin ;
• . une première série de galets venant en appui sur l'extrémité supérieure du conformateur, pour centrer le mandrin et pincer la gaine qui s'enfile sur ladite extrémité ;
• . au moins une paire de roulettes d'entrainement motrices qui viennent en contact avec lesdits roulements de contre-appui et pénètrent à l'intérieur du rétrécissement du mandrin ;
• . une deuxième et une troisième série de galets en appui sur le mandrin respectivement dans la moitié supérieure et dans la moitié inférieure de ce dernier et destinés à assurer un centrage constant et rigoureux du mandrin par rapport à l'axe de pose des manchons tout en évitant un échappement de ce mandrin desdites roulettes d'entraînement ;
• . un moyen de découpe, connu en soi, de la gaine en tronçons ou manchons de longueur prédéterminée et disposé autour de la base du mandrin.

According to the invention, the new vertical assembly for opening and transferring the sheath then cutting into sections is characterized in that it essentially comprises the combination of the following means:

• . a peripheral elongated mandrel having, substantially in its middle part, a narrowing / inside of which is fixed at least one pair of counter-bearing bearings, a circular sector of which protrudes from the narrowing, the mandrel further having, in its hollow bottom part, a movable piston at the end of which is fixed a hollow imprint intended to come to cap the container to be sleeved;
• . a support or shaping device fixed on the head of the mandrel, of small thickness, slightly conical downwards and the upper end of which has a width slightly less than the flat width of the sheath which slides over said support before reaching, in expanded form, on the head of the mandrel;
• . a first series of rollers coming to bear on the upper end of the former, for centering the mandrel and pinching the sheath which slides over said end;
• . at least one pair of driving drive rollers which come into contact with said counter-bearing bearings and penetrate inside the narrowing of the mandrel;
• . a second and a third series of rollers bearing on the mandrel respectively in the upper half and in the lower half of the latter and intended to ensure a constant and rigorous centering of the mandrel relative to the axis of fitting of the sleeves while avoiding an exhaust of this mandrel from said drive rollers;
• . a cutting means, known per se, of the sheath into sections or sleeves of predetermined length and disposed around the base of the mandrel.

We have already disclosed, in sleeving apparatuses, the principle of a floating vertical mandrel (or guide) having over a part of its length a reduction in diameter, with the placement of rollers in the cavities thus created in order to keep the guide in vertical position. However, this system has been used either under very specific conditions of use .. requiring a very sophisticated mandrel and additional means (see for example American patents No. 2,623,673 of August 6, 1949 and No. 2,846,835 of November 14, 1955) or in combination with special suction applicators intended for driving the sheath (see for example American patent N ° 3,738,210 of March 23, 1971); in this case, we do not see how the mandrel, able to pivot in all directions, can be maintained correctly only by the support rollers; However, it is known that the slightest folding of the sheath and any verticality shift inevitably lead to the defectiveness of the sleeve, in particular when the latter is printed, which represents the majority of cases.

In the system according to the invention, the mandrel is held in at least three sectors along its length and the downward entrainment of the plastic film is caused by the combination of the driving drive rollers - which also serve as a means main lift of the mandrel- and counter-bearing bearings integral with the mandrel itself. This without vacuum suction or other chain or belt transfer means as in known methods.

In practice, these drive rollers for the counter-bearing bearings are driven by a motor at a speed and according to on-off times regulated by an electronic time delay which defines the suitable length of the sleeve to be cut. In addition, the rollers are provided at their periphery with a rubber band of suitable hardness to prevent slipping or tearing of the film from the sheath as well as the downward shift of the suspended mandrel.

According to another characteristic of the invention, the head of the mandrel, slightly thinned upwards, is integral with a support element called here conforming because it has the function of spreading or dilating progressively and continuously the walls of the flat sheath feed to the cylindrical section of the chuck head. This conformator is a flat element whose section advantageously has the structure of an elongated hexagon so that the fold of the sheath (produced by sealing the superimposed walls of a plastic film) follows a point or bevel of the hexagon. The height of this support element is calculated so as to allow the conical conformation of the sheath on a mandrel whose diameter is very close to that of the sheath.

Preferably, the mandrel is produced with a grooved surface in order to avoid any sticking of the thermoplastic film by suction, static electricity or other phenomenon during the routing of the sheath along this mandrel.

In accordance with another improvement, the device or machine according to the invention is made completely autonomous and adapted to all types of packaging or receptacles so that this machine can operate immediately on any conveyor without special adaptation for synchronization.

According to this improvement, the frame of the machine is integral, in its lower part, on the one hand with a cell wheel driven, by means of pinions and toothed belt, by means of a standard Maltese cross or system Fergusson type, said wheel allowing the automatic positioning of the container under the mandrel; and, on the other hand, an endless screw controlling the introduction of the containers from the conveyor to the interior of the cells of the wheel.

• . Figure 1 : une vue de face, partiellement en coupe, d'un ensemble vertical selon l'invention ;
• . Figures 2a et 2 b : des vues, respectivement de profil et de dessus d'un conformateur tel que celui monté sur la tête du mandrin de la figure 1.
• . Figure 3 : une vue en projection sur un plan, illustrant sous le bâti de la machine des moyens de synchronisation avec un système de positionnement des récipients sous le mandrin de pose de manchons ;
• . Figure 4 : une vue de profil de ce bâti inférieur et d'une partie desdits moyens de synchronisation ;
• . Figure 5 : une vue partielle selon la ligne AA de la-figure 2, illustrant le montage d'un dispositif à brosses rotatives, destinées à positionner le manchon à la hauteur voulue du récipient, après pose du manchon par le mandrin.

; Still other characteristics will appear during the description which follows, relating to a nonlimiting embodiment illustrated by the appended drawings which represent diagrammatically:

• . Figure 1: a front view, partially in section, of a vertical assembly according to the invention;
• . FIGS. 2a and 2b: views, respectively of profile and from above, of a shaping device such as that mounted on the head of the mandrel of FIG. 1.
• . Figure 3: a view in projection on a plane, illustrating under the frame of the machine synchronization means with a positioning system of the containers under the sleeve-laying mandrel;
• . Figure 4: a side view of this lower frame and part of said synchronization means;
• . Figure 5: a partial view along line AA of Figure-2, illustrating the mounting of a device with rotary brushes, intended to position the sleeve at the desired height of the container, after installation of the sleeve by the mandrel.

As shown in FIG. 1, the device forms part, as the main member, of an automatic machine continuously supplied by a flat sheath of heat-shrinkable plastic and intended to carry out the successive operations of opening the sheath, transfer of the latter to a cylindrical element with speed programming, cutting the sheath into sections of predetermined length, depositing the latter around the container to be sleeved then heat shrinking with a heating device mounted for example on an endless conveyor. The sheath supply and heat shrinking means are not part of the invention and can be, for example, those described in the European patent published under the number 0 000 851. Furthermore, upstream of the device in FIG. 1, the plastic sheath can advantageously be subjected to perforation or precut by the same means as those recommended in the aforementioned patent.

According to the drawings, the vertical assembly according to the invention essentially comprises the following members: a shaper 1 fixed on the head of a floating mandrel 2, solid in its upper part up to the hollowed out or narrowed area 2 'then hollow in its lower part 2 "which is provided with a movable piston 3 at the end of which is fixed an indentation 4 intended to come to cap the head of the object to be sleeved 5. The piston has a mild steel head and its movement is controlled by induction by means of an electromagnet coil which surrounds the mandrel (not shown in the drawing). This piston-impression system constitutes a means of centering and guiding the film during the fitting of the sleeve. The vertical assembly comprises in addition, at the lower end of the mandrel 2 a device 6 for cutting the sheath into sleeves or sections of known type, for example that described in the aforementioned European patent.

The system for supporting the mandrel 2 is schematically represented at the level of the recess 2 '. It includes driving drive rollers 7, 7 'which penetrate inside the narrowing of the mandrel and are in contact with idler counter-bearings 8, 8' mounted inside the mandrel and whose circular sector projecting from the narrowing 2 'is tangential to the generatrix of the mandrel 2. The rollers 7, 7' are driven by an assembly shown in dotted lines and comprising a series of rollers 9, 10, 11 driven by belt by the motor 12. In in addition, these rollers 7, 7 ′ are covered on their periphery with a rubber which is hard enough to prevent any crushing during the pressure with the bearings 8, 8 ′ and thus avoid the sliding of the plastic film (or sheath) as well as the offset down the recess 2 'of the mandrel. According to an alternative embodiment, one can install at the narrowing base 2 'another set of counter-bearing bearings (not shown), also in contact with the rollers 7 and 7'. Each bearing 7, 7 '... can be single or double. The speed as well as the rotation time of the drive rollers 7, 7 ′ are regulated by an electronic delay which makes it possible to define exactly the length of sheath corresponding to a sleeve to be deposited on the object 5 after cutting 6.

In addition to the lifting means described above, the mandrel 2 must be kept in constant and rigorous centering with respect to the laying axis XX 'of the sleeve on the container; it is also advisable to avoid any pivoting of this mandrel during work. To obtain this result, it was mounted in contact with the mandrel 2: a series of rollers 13 near the thinned head of the mandrel then another series of rollers 14 in the lower part of the mandrel. Each series is composed for example by a pair of rollers opposite with respect to the axis of the mandrel and each arranged in a plane perpendicular to that of the drive rollers 7, 7 '. In addition, another series of rollers 15, 15 '(for example two pairs) is mounted in abutment on the upper end of the shaper 1 in order to perfect the centering of the mandrel and to ensure a good pinching of the plastic sheath 16.

As can be seen in FIGS. 2a and 2b, the conformator is a flat element, of small thickness, with walls slightly conical towards the bottom and the section of which is preferably hexagonal so that the fold of the plastic sheath can be inserted , during the transfer, along the generator of the bevel 17 (or tip) of the hexagon. The former 1, fixed on the head of the mandrel 2, has a height such that the plastic sheath 16 can expand sufficiently and reach the thinned head of the mandrel with an opening corresponding substantially to the diameter of the latter. The upper end 18 of the shaper 1 has a width slightly less (for example a few tenths of a mm) than the flat width of the plastic sheath.

Preferably, the mandrel 2 has a grooved or striated surface over its entire periphery so as to facilitate the sliding of the plastic film during the transfer operation. As shown in ⁱ ct figure 1, the mandrel has a cylindrical section. However, the shape may be different, for example: elliptical, rectangular, square or variants of these structures.

In operation, the vertical assembly according to the invention automatically provides: the opening of the plastic sheath 16, the transfer of the latter along the guided and centered mandrel 1, with the sheath being driven by the rollers 7, 7 ′ then the cutting of the sheath into sleeves of predetermined length and the placing of the latter on the containers 5 with rigorous and permanent centering thanks to the assembly of the piston 3 and of the associated imprint 4. According to a variant, the cutting operation by means 6 can be done when a sleeve has just been deposited on the corresponding container.

It will be noted that the height of the shrinkage 2 ′ of the mandrel 2 must be large enough to give "softness" to the plastic film so as to avoid tearing. In practice, this height must be at least equal to the section of the mandrel.

Figures 3 to 5 illustrate an improvement to make the sleeve fitting device completely autonomous and suitable for all types of receptacles, with adaptation to any type of conveyor.

As can be seen in Figures 3 and 4, the lower frame 1.9 of the machine (as described above) is integral with a wheel 20 formed by a series of cells 21, single or double, in which will come fit the containers to be sleeved (the latter and the conveyor are not shown in the figures). The wheel 20 is driven by a toothed belt 22 and pinions 23, 24 by means of a system 25 of the Maltese cross type. The pitch of the wheel can be modified by simply changing the pinions 23, 24. In addition, the wheel 20 is adjustable in height according to the type of receptacle to be sleeved.

The frame of the machine also supports an endless screw 26 driven by means of belt 27 and pinions 28, 29 by the rotary shaft 30. This endless screw controls, in a manner known per se, the introduction of the containers into each of the cells 21, its originality consisting in the fact that it is made integral with the laying machine according to the invention.

By. elsewhere, as can be seen in the section of FIG. 5, the same shaft 30 can drive, at the outlet of the machine, by means of belt 31 and pinions 32, 33, a series of rotary brushes 34, 35, with variable spacing, which drive the sleeve from top to bottom around its receptacle and therefore facilitate the positioning of this sleeve, in particular in the case where only a part of the container must be covered by the latter.

The arrowed line 36 in FIG. 3 indicates the direction of movement of the containers on the conveyor, which can be of any type.

It will be noted that the cell wheel 20 is indexed step by step either by the abovementioned Maltese cross (item 25) or by an equivalent Fergusson type system. This indexing allows the positioning of the container to be sleeved rigorously under the mandrel and in continuity therewith.

In addition, on the cell wheel, a torque limiter can be provided causing the wheel drive to be triggered, this in order to guard against any risk resulting from improper introduction of the container into the wheel; such a mechanical trip also has the effect, via a contactor, of instantly stopping the machine.

Of course, the invention is not limited to the embodiment illustrated by the drawings and extends to all variants of execution of equivalent functions and structures.

Claims (9)

1. Vertical assembly with floating mandrel for an automatic machine supplied with a continuous sheath of heat-shrinkable plastic and intended for cutting, at a programmed rate, the sheath into sections or sleeves and then for fitting the sleeves around containers to be coated or decorated, assembly being characterized in that it comprises the combination of: a mandrel - elongated (2) having, substantially in its middle part, a narrowing (2 ') inside which is fixed at least one pair of counter bearings -support (8.8 '), a circular sector of which projects from the narrowing, the mandrel also having in its lower hollow part, a movable piston (3) at the end of which is fixed a hollow imprint (4 ) intended to cap the container to be sleeved (5); a support or conformator (1) fixed on the head of the mandrel, of small thickness, slightly tapered downwards and whose upper end (18) has a width slightly less than the flat width of the sheath (16) which s 'threads on said support before reaching the head of the mandrel; a first series of rollers (15, 15 ') bearing on the upper end of the shaper (1), to center the mandrel and pinch the sheath which slides over said end; at least one pair of driving drive wheels (7,7 ') which come into contact with said counter-bearing bearings (8,8') and penetrate inside the narrowing (2 ') of the mandrel; a second (13) and a third (14) series of rollers bearing on the mandrel respectively in the upper half and in the lower half of the latter and intended to ensure constant and rigorous centering of the mandrel relative to the axis of poses sleeves while avoiding an escape of this mandrel of said drive rollers; cutting means (6), known per se, of the sheath into sections or sleeves, disposed around the base of the mandrel. 2. Assembly according to claim 1, characterized in that the drive rollers (7,7 ') of the counter-bearing bearings (8,8') are driven by motor (12) at a speed and according to times of on-off regulated by an electronic time delay which defines the suitable length of the sleeve to be cut and in that the rollers have their periphery coated with a rubber band of suitable hardness to prevent slipping of the sheath and the fall of the mandrel towards the low. 3. Assembly according to any one of claims 1 or 2, characterized in that the conformator (1) is a flat element, the section of which has the structure of an elongated hexagon, the fold of the thermoplastic sheath being inserted around a point (17) of the hexagon, the height of said element being calculated to allow cone conformation of the flat sheath on the cylindrical mandrel whose diameter is close to that of the sheath. 4. An assembly according to any one of claims 1, 2 or 3, characterized in that the head of the mandrel (2) is slightly thinned up and in that this mandrel has on its surface grooves or grooves to facilitate the film slip. 5. The assembly of claim 1, characterized in that said first series of rollers (15, 15 ') comprises two pairs of rollers opposite in pairs relative to the upper end of the former and arranged in a plane parallel to that of said drive wheels. 6. An assembly according to any one of claims 1 or 5, characterized in that each of said second (13) and third (14) series of rollers bearing on the mandrel comprises two rollers opposite with respect to the axis (X X ') of the mandrel (2) and arranged in a plane perpendicular to that of the drive rollers (7, 7'). 7. The assembly of claim 1, characterized in that the height of the peripheral narrowing (2 ') on the mandrel (2) is at least equal to the section of the latter. 8. An assembly according to claim 1, characterized in that the frame (19) of the machine is integral, in its lower part, on the one hand with a wheel (20) with cells (21) -adjustable in height and at not variable - driven, by means of pinions (23, 24) and toothed belt (22), by means of a Maltese cross (7) or Fergusson system, said wheel allowing the automatic positioning of the container under the mandrel; and, on the other hand, an endless screw (26) controlling the introduction of the containers from the conveyor to the interior of the cells of said wheel. 9. An assembly according to claim 8, characterized in that the shaft (30) for supporting the worm (26) further controls, by the set of suitable pinions (32, 33) _J two rotary brushes (34, 35) intended to position the sleeve at the desired height of the container, after the installation of this sleeve by the floating mandrel.

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