EP2660173A1

EP2660173A1 - Automatic rewinder for forming reels of air bubble film (or similar materials) with or without core

Info

Publication number: EP2660173A1
Application number: EP20130153769
Authority: EP
Inventors: Maurizio Mencarelli
Original assignee: Torninova Srl
Current assignee: Torninova Srl
Priority date: 2012-05-03
Filing date: 2013-02-01
Publication date: 2013-11-06
Anticipated expiration: 2033-02-01
Also published as: SI2660173T1; EP2660173B1; ITMI20120741A1

Abstract

A description is given of an automatic rewinding machine (100) for the rewinding of an air bubble film (3) (or similar materials such as PE foam, XPS foam, and others) comprising rotating support means (6) suitable for supporting one end of a respective horizontal leaf expandable winding shaft (4) whereon a first reel A will be formed, and one end of at least one other horizontal rotating leaf expandable winding shaft (4',4"), said winding shafts forming at least one winding station and a reel unloading station, cutting means (20) suitable for cutting a film of air bubble plastic (or similar materials such as PE foam, XPS foam, and others) characterised in that it provides wrapping means (30), placed opposite to said cutting means (20), comprising horizontal rotating rollers (31, 32, 33) suitable for partially surrounding said winding shafts (4,4',4"), and for guiding the winding of the cut portion of the film (3) on said shafts, said winding shafts (4,4',4") being leaf expandable shafts comprising a plurality of circular sectors (62) moving radially with respect to the axis of the respective shaft (4,4',4").

Description

The present invention relates to an automatic rewinding machine for air bubble plastic film (or similar materials, such as PE foam, XPS foam, and others) suitable for the continuous production of reels, with or without core, to be integrated in a process of continuous production of said film.
More particularly the present invention relates to a rewinder as defined above, capable of winding said film by means of leaf expandable spindles, optionally without the aid of a cardboard core and without the use of glue, thus eliminating the down times for the loading of the new core, as well as its costs.
Even more particularly the present invention relates to such a rewinder able to rewind, in the same length of time, a higher number of reels compared to the normal production process in that the phases of loading of the new cardboard core and its subsequent gluing are missing. This advantage is also present in the case of use of a core in that it is not necessary to slow down the speed of winding of the spindle in order to facilitate the winding of the plastic film on the core.
The rewinder for air bubble film (or similar materials such as PE foam, XPS foam, and others) is a machine or a system able to form continuously reels of film of a given length, placed downstream of a plant which produces film in line uninterruptedly. This rewinder generally has two stations represented by two horizontal parallel shafts (axes), one dedicated to the rewinding of a first reel and the other dedicated to the loading of the cardboard core of a second reel to be rewound subsequently to the first reel.
After having performed the cutting of the film the position of the two stations is inverted so as to move the first formed reel towards the zone of discharge and bring closer to the flap of cut film the second cardboard core, previously wetted with glue, so as to wind said film on said second core. The loading of the cardboard core takes place manually or automatically after having discharged the first reel formed.
In these machines the phase of loading of the cardboard core and of subsequent gluing of the new core is a critical and slowing-down moment of the rewinding process in that adhesive/bi-adhesive tapes and/or binders have to be positioned on the core and it has to be ensured that the initial part of the cut film embraces said core completely without forming pockets in order to avoid defects of winding.
In addition to what is stated above in relation to the slowing-down of the process, another disadvantage in using cardboard cores consists both of their cost and of the possible problems of space due to the storage of the same cores.
Moreover the use of tapes and/or binders in the cores also represents a further economic disadvantage both due to the cost of the same and due to the need to use labour for the application of the tape or, in the case of glues, to use automatic hot-melt gluing units which need thorough and frequent maintenance.
Therefore, in the sector of the winding of air bubble film, it is desirable to have a machine for winding which avoids the disadvantages of the winding with core.
The preparation is also known of reels of air bubble film without core by means of a discontinuous process which provides for the use of a machine formed by a single winding station: however the use of such a machine requires the interruption of the forward movement of the film being wound when the film has to be cut, after the reel has reached the required length.
This is disadvantageous due to the evident lengthening of the production times. Moreover such a machine cannot be used for the continuous winding of a plastic bubble film coming from a continuous production plant.
Moreover, in this process, the phase of rewinding has to be suspended during the discharge phase of the reel already formed: this suspension results in a further reduction in the productivity with respect to a process of rewinding in the presence of a core as described above.
The lower productivity of this discontinuous process is also due to the fact that the start of the reel is formed at low speed to ensure that the film can wind easily on itself, and also evenly: this results in a process with ramps of acceleration and deceleration which make the production rate inconstant.
US 2,650,038 describes an automatic machine for the winding off line of paraffin paper in order to form small rolls of paper without core starting from a reel large in size, which uses expandable spindles with expander bars.
The Applicant has observed that the use of such a machine with such spindles in the formation of reels of air bubble plastic film (or similar materials such as PE foam, XPS foam, and others) would be impractical since these spindles would not allow an easy extraction of the reel. This is due to the fact that the bubble film, being much less rigid than paraffin paper, goes to occupy, during winding, the empty space between the bars of the spindle as winding proceeds due to the weight of the reel being constructed.
This results in a reel having a central hole with irregular dimensions, therefore making the extraction of the newly formed reel difficult if not even impossible. Moreover a central hole with irregular dimensions may entail, in the case of plastic films, an irregular winding along the length of the spindle to be wound with consequent damage to the film.
Moreover said spindles with bars may also damage some bubbles, in particular those which are located at them, seeing that the pressure is greater in said splines compared to other points of the reel.
The object of the present invention is to provide a rewinding machine for air bubble film (or similar materials such as PE foam, XPS foam, and others) with or without core, able to overcome the disadvantages of the prior art, which is able to rewind also without the use of cardboard cores and consequently without the use of glue and/or adhesive tapes and of labour for its application.
A further object is that of providing such a rewinding machine which allows several operations to be performed in the same timespan so as to increase the production of reels of an air bubble film (or similar materials such as PE foam, XPS foam, and others) coming from a continuous production plant, without causing any damage to the film and/or to its bubbles, also ensuring winding which is even along the entire length of the winding spindle, and therefore along the entire length of the reel.
These objects are achieved by the rewinding machine in accordance with the invention having the features listed in the annexed independent claim 1.
Advantageous embodiments of the invention are disclosed by the dependent claims.
The object of the present invention is an automatic rewinding machine with at least two winding stations for the continuous in-line rewinding of air bubble plastic film or similar materials (such as PE foam, XPS foam, and others) in sheet form, exiting continuously from a continuous production plant, said machine comprising

a peripheral frame in the form of support structure;
at least one guided cylinder co-operating with another cylinder so as to form an assembly of driving and tensioning for said film;
a plurality of idle cylinders for feeding said film to the winding station;
a support rotating with respect to its horizontal axis, made up of a vertical platform or of a box beam, provided with at least one station for the winding, and a discharging station made up of at least two horizontal rotating expandable shafts for the support of the reels being wound, placed downstream of said guided cylinder;
means for discharging reel near an opening for the exit of a reel;
an assembly for cutting the film being wound on one of the two stations, provided with a mechanical arm hinged to the frame and supporting a blade suitable for only the cutting of the air bubble plastic film (or similar materials such as PE foam, XPS foam, and others), which provides for forming two respective cut flaps of the sheet of the aforementioned film, and is without rollers co-operating in the winding of the film;
a motor-driven cylindrical brush for facilitating the winding of the cut flap of said sheet of film on the winding shaft to be wound,

a wrapping assembly, provided with at least three rollers, staggered one in relation to the other, suitable for partially surrounding one of said horizontal rotating shafts for the support of the reels being wound, and guiding, in co-operation with said motor-driven brush, the winding on said shaft of the remaining cut flap of the film coming from the continuous production process;

The cutting assembly is suitable for performing a cut in a point of the film placed distant from the expansion shaft and not lying on the portion of said film wound on said winding shaft in order to determine a portion of film to be wound of appropriate length so as to guarantee an efficient winding, maintaining the speed of winding constant.
This is made possible also thanks to the motor-driven brush which avoids the reel being started at low speed in order to be able to wind without defects the film on the spindle, therefore making the production rate advantageously constant.
In particular the point of the film wherein the cut is performed is distant:

from the point wherein, during the cutting, the film is in contact simultaneously with the expansion shaft and the central roller of the wrapping assembly which is closer and adjacent to said winding shaft; and
from the point wherein, during the cutting, the film is in contact simultaneously with the brush and the outermost roller of the wrapping assembly.

The invention will now be described with reference to a preferred embodiment purely by way of an example (and therefore non-limiting) illustrated in the accompanying drawings, where:

Figure 1a shows in plan view the rewinding machine of the present invention;
Figure 1b is a sectioned view taken along line 1b-1b illustrating the positions of three leaf expansion shafts;
Figure 1c is a sectioned view taken along line 1c-1c illustrating the positions of a reel during winding in two distinct phases of the rewinding process performed by the present rewinding machine;
Figure 2 is a sectioned view like Fig. 1c illustrating the positions of the elements forming the present machine in the phase preceding the cutting of the film being wound on a first reel;
Figure 3 is a sectioned view like Fig. 1c illustrating the positions of the elements forming the present machine in the phase of film cutting of the rewinding process;
Figure 4 is an enlarged view of the detail C indicated in Fig. 3;
Figure 5 is a sectioned view like Fig. 1c illustrating the positions of the elements forming the present machine after the cutting during the discharging phase of a first reel;
Figures 6a) and 6b) are sectioned views of the leaf shaft respectively in closed position and in open position (in expansion);
Figure 7 is a schematic view in vertical section like that of Figs. 1c and 2 illustrating a second embodiment of the present rewinding machine provided only with two spindles;
Figure 8 is a further enlarged view of Figure 4.

In the accompanying drawings the corresponding elements will be denoted by the same reference numerals.
As illustrated in Figs. 1b and 1c, the rewinding machine of the present invention, denoted overall by reference numeral 100, provides a support 6 made up of a platform, mounted vertically, suitable for supporting an end of a first horizontal winding shaft 4, constituted by a leaf expandable shaft, whereon a first reel A (Fig. 1c) will be formed starting from a film 3 coming from a plant of production and thermoforming (not illustrated in the drawings).
Fig. 1c is a "fictitious" view which shows the reel A both during the phase of winding and during the phase of discharge.
Said support 6 also holds one of the ends of two other rotating leaf expandable shafts 4' and 4" (Fig. 1b), also horizontal and placed at 120° with respect to the shaft 4: before the start of the rewinding process the shafts 4' and 4" are in standby, respectively in an upper position 4' and at the cradle of extraction 8 for the reel unloading (in Fig. 1b and Fig. 5) while the first shaft 4 whereon the first reel A is to be formed is in an intermediate position between the two.
In practice said leaf expandable winding shafts 4, 4', 4" form at least one winding station and one reel unloading station.
Hereinafter, for the sake of convenience, the shafts 4, 4', 4", will also be called "spindles" in order to distinguish them from other rotating shafts present in the present rewinding machine.
Said support 6 is also mounted vertically on a horizontal rotating shaft 9 passing through its centre, resulting therefore in a platform which rotates around its central horizontal axis.
The ends of the spindles 4, 4', 4" opposite to those restrained to the platform 6 are supported by three respective clamps 10 arranged on three respective removable arms 11 which are mounted on the rotating shaft 9 and integral therewith.
Each of said removable arms 11 is actuated by a respective piston mounted on a respective fixed arm 13, provided at the end of an idle roller suitable for facilitating the tension of the film 3 during the rotation of the support 6 at the phase of cutting and rewinding as will be illustrated herein below.
Such an assembly means that the spindles 4, 4', 4", and the respective reels deriving therefrom, change position in space as a function of the operations to be performed in the process of rewinding as will be illustrated in detail herein below.
The rewinding machine 100 also has a guided chromed cylinder 1 (motor-driven) and a plurality of idle cylinders 2 for accompanying of the film towards the rewinder machine which feed the film 3 coming continuously from the plant of production and thermoforming in continuous mode (not illustrated) towards the first leaf expandable spindle 4 (Fig. 1b) and around which the first reel A (Fig. 1c) will be formed.
During rewinding, the first leaf expandable spindle 4 is in expansion (Fig. 6b) in open position, while during the phase of unloading of the reel it is deflated, in closed position, with subsequent reduction in its diameter (Fig. 6a) in order to allow easy extraction of the reel produced.
A second rubber-covered cylinder 14 is also provided, actuated by a pneumatic piston integral with the frame structure 40 of the machine, suitable for co-operating with said first cylinder 1 by means of contact, with the purpose of constituting both an assembly of drive and tensioning for the air bubble film (or similar materials such as PE foam, XPS foam, and others) in the present rewinder: the motor-driven cylinder 1 and the rubber-covered cylinder 14 pull the film 3 coming from the plant of production and thermoforming of the film, which is positioned upstream, during the functioning of the machine. Said cylinders 1 and 14 are always in closed position on the film 3.
Once the first reel A has reached the preset length it starts its angular movement through 120°, anticlockwise (arrow), in order to bring the first reel A and the respective spindle 4 above the unloading saddle 8 in the position of reel unloading, in proximity of the outlet opening 12 as illustrated in Fig. 1c.
In this configuration the procedure of cutting starts while simultaneously the rewinding on the second expandable spindle 4', 4" takes place in order to form a second reel B (Fig. 5); the cutting operation takes place by means of the actuation of other groups of elements forming the present machine 100. More particularly the following will be actuated:

a cutting assembly 20 placed above the plane of the sheet of film 3 being wound;
a wrapping assembly 30, placed below the plane of the sheet of film 3 being wound, which is provided with three rollers 31, 32, 33, staggered one in relation to the other, which extend at least for the entire length of the expansion shaft 4 to be wound so as to guarantee an even winding along the entire length of said expansion shaft. Said wrapping assembly 30 is in general suitable for surrounding partially the horizontal rotating shaft (inflated leaf expandable spindle), for guiding the winding of the film alternatively on said spindles 4, 4', 4", and in this particular case of Figs. 1-5, 7 for surrounding the upper portion of the circumference of said shaft.

The cutting assembly 20 is made up of a mechanical arm 21 having one end hinged to a shaft 26 which is integral with the support structure 40 of the rewinding machine 100, as illustrated in Figure 1c.
At the other end of this arm 21, in distal position with respect to the shaft 26, a cylindrical brush 23 (brushing roller) is attached which is motor driven and is suitable for facilitating the wrapping of the new spindle 4, or 4', or 4" (alternatively) by the second cut portion of film being rewound 3 in co-operation with the rollers of the wrapping assembly 30, as will be described subsequently in detail.
Said arm 21 is actuated by a first piston 22 which is also integral with the support structure 40 (frame) of the rewinding machine 100. On said arm 21 a curved rod 24 is hinged which carries in the free end a blade 25, suitable for cutting a film of air bubble plastic (or similar materials such as PE foam, XPS foam, and others).
On said arm 21 a second piston 27 is also mounted, suitable for actuating said curved rod 24, and is attached thereto in such a way that the actuation of the piston 27 causes the rotation of said curved rod 24 with respect to the arm 21.
Said cutting assembly 20 is positioned opposite to the wrapping assembly 30 with respect to the sheet of film 3, and in such a way, with respect to said wrapping assembly 30, as to cut said sheet of film 3 in a point E (Fig. 8) which is distant from the expansion shaft and/or not lying on the portion of said film wound on said winding shaft.
More particularly said point E is placed distant from the point C wherein, during the cutting, the film 3 is in contact with both said expanding winding shaft 4,4',4" and central rotating roller 32 which is closer and adjacent to said shaft 4,4',4" during the cutting.
Moreover, contrary to what occurs in the art in the case of film with core, said cutting assembly 20 does not co-operate in any way with the spindle 4 during the winding of the cut flap and is without rollers which co-operate in the winding of the film.
"Distant" here is intended to identify any point E of the film 3 which is located beyond the spindle 4 and beyond the external roller 33 and not in proximity to the spindle being wound 4, 4', 4": for example the point E can be at a distance from the point C equal to at least the semi-circumference of the roller 33 of the wrapping assembly 30, it being possible for said distance to be at most equal to twice the circumference of said outermost roller 33.
The wrapping assembly 30 is made up of a mechanical arm 34 having one of its ends hinged to a shaft 38 integral with the support structure 40 of the rewinding machine 100.
Said mechanical arm 34 is actuated by a first piston 36 also integral with the support structure 40. On one of the ends of this arm 34, in distal position with respect to the shaft 38, a hook-shaped support 35 is hinged, having a portion of the profile with arched shape 39, which is actuated by a second piston 37 mounted on said arm 34 in order to allow the rotation of said hook-shaped support 35 with respect to said arm 34.
The arched portion 39 of the profile of the hook-shaped support 35 is such as to allow said support 35 to surround partially the inflated spindle, guiding in fact the winding of the cut film on said spindle.
In practice, after the cutting, said winding is guided by the three rotating rollers 31, 32, 33, attached to the hook-shaped support 35, which are suitable for co-operating, alternatively, with the spindle 4, 4', 4", in association with the cylindrical brush 23 of the cutting assembly.
More particularly, during use, the central roller 32 is intended to co-operate with the spindle 4 during winding by pressing on the film 3 while, simultaneously, the outermost roller 33 is suitable for co-operating with the motor-driven brush 23, also pressing on the film 3.
As illustrated in Figure 2, while the first reel A supported by the spindle 4 is moved into unloading position at the unloading saddle 8, the procedure of cutting and winding of the film 3 begins. At the start the cutting assembly 20 and the wrapping assembly 30 are actuated by respective pistons 22 and 36 so as to make the relative mechanical arms 21 and 34 rotate until reaching a horizontal position.
It should be noted that during this phase of moving of the cutting assembly 20 close to the film 3, the cutting blade 25 is not actuated and is distant from the film 3 to be cut in that substantially aligned with the arm 21 placed horizontally (Fig. 2).
Subsequently the hook-shaped support 35 of the wrapping assembly 30 is rotated with respect to the arm 34, enabling the arched portion 39 of the hook-shaped support 35 to surround, without touching it, the second inflated spindle 4', 4" (in expanded form and in open position) which is placed on the rotating support 6. In this way the film 3 is in contact both with an expandable spindle portion and with an outermost portion of roller 33 (idle yet rotating because driven by the motor-driven spindle 4), as illustrated in Fig. 2, sliding therefore between the spindle and said outermost roller 33.
In this situation, thanks to the position of the wrapping assembly 30, the film 3 to be cut, which has to pass between the spindle and the outermost rotating roller 33 of the wrapping assembly 30, winds on both an expandable spindle portion and an outermost rotating roller portion 33, as illustrated in Fig. 2.
Since during the actuation of the arm 21 of the cutting assembly 20, the cylindrical brush 23 (motor driven) has also been carried in proximity of said expandable spindle and of said outermost rotating roller 33 of the hook-shaped support 35, said brush 23 (not yet actuated) is located in proximity of the outermost rotating roller 33. It should be noted that in this situation (brush 23 lowered but not yet actuated) the film slides, rubbing on the brush 23 which is at a standstill, and drives the outermost roller 33.
As illustrated in Figure 3, at the time of cutting the curved rod 24 is actuated by the piston 27 in such a way as to rotate appropriately downwards said curved rod 24 and to lower the blade 25 at the outermost roller 33 around which the film 3 to be cut passes: as illustrated in the enlargement of Fig. 4, the blade 25 cuts the film 3 descending flush with the external rotating roller 33 and isolating the reel A from the remaining part of the film 3 being wound.
The portion of film 3 which has been cut and which is in contact with the outermost roller 33 goes to embrace the expandable spindle 4' of the new roll B (Fig. 5) and winds around it thanks to the inertia after the cutting and to the aid supplied by the central roller 32, also in contact with the portion of film 3 which has been cut and which covers partially said spindle, said central roller 32 and outermost roller 33 rotating in a direction contrary to the direction of rotation of the spindle 4.
Finally the motor-driven brush 23, actuated just before cutting with a direction of rotation contrary to the direction of rotation of the spindle and to the forward movement of the film 3, helps the flap of newly cut film to complete the winding on the same spindle.
As soon as cutting takes place, the flap no longer connected with the "old" roll A is enclosed around the "new" spindle (second spindle) thanks to the fact that the brush 23 has been actuated in rotation and that the directions of rotation of the brush 23, of the outermost roller 33 and of the central roller 32 are contrary to that of rotation of the new spindle 4' (Fig. 4).
In order to facilitate further the correct positioning of the flap of cut film around the new spindle it is possible to provide one or more puffs of compressed air coming from a manifold placed at the wrapping assembly 30.
It should be noted that the aforementioned motor-driven brush 23 does not co-operate in any way with said spindle 4 to be wound but only with the outermost roller 33 of the wrapping assembly and that, during the cutting, both said brush 23 and said outermost roller 33 are in contact with the film 3 in a point D which precedes the point E of cutting, in the direction of winding of the film indicated by the arrow in Fig. 8, but follows the point C.
The arrangement during use of the wrapping assembly and of the cutting assembly, combined with the use of the motor-driven brush, allows efficient and uniform winding, avoiding starting the reel at low speed in order to be able to wind the film evenly on the spindle.
This therefore allows advantageously the production rate to be maintained constant, also thanks to the fact that the cutting takes place so as to obtain a portion of film to be wound such as to allow a sufficient covering of the spindle also at the speed of winding normally used in continuous machines.
After cutting, the cutting assembly 20 and the wrapping assembly 30 return into the same initial rest position indicated in Figs. 1b and 1c, while the roll A is unloaded onto the extraction cradle 8 as illustrated in Figure 5 without interfering with the winding of the new roll B (second roll, Fig. 5).
In the phase of reel unloading the extraction cradle 8 rises until intercepting the reel A, the clamp 10 (Fig. 1c) opens and rotates until moving outside of the overall dimension of the reel A freeing one of the ends of the spindle 4 whereon the reel A has formed. Subsequently the extraction cradle 8 is extracted through the opening 12 (Fig. 1c) allowing the reel A to withdraw from the relative spindle 4, now deflated and therefore with smaller diameter, which is integral with the rotating support platform 6.
This phase of unloading of the first reel A takes place simultaneously to the rewinding of the new reel B (second reel) in intermediate position, while a further expandable spindle 4" (third spindle) in upper position waits to be used following a further anticlockwise rotation of the support 6 after the completion of the reel B which, by means of this rotation, is brought into the section of reel unloading.
Moreover the rewinding machine of the present invention provides preferably means for automatic control such as a central command and a software program (PLC) for the automatic management of the various phases of rewinding.
Referring to Figures 6a) and 6b), the leaf expansion shaft 4, 4', 4", is formed by a first hollow internal tubular element 60 which is coaxial to a second more external hollow shaft 61 having a larger diameter.
Said first hollow internal tubular element 60 is made up of a rubber tube (air chamber) suitable for expanding as will be described herein below.
Slidingly restrained to said second external shaft 61 are four elements 62, in the form of circular sector, also referred to as leaves, suitable for moving radially outwards with respect to said second shaft 61. Said leaves 62 are placed at 90° one with respect to the other and are restrained to said second shaft 61 by means of four tubes 63 sliding radially outwards, each one provided with a widened base 64 which acts as end of travel for the radial movement outwards of said tubes 63 with respect to said second shaft 61.
Said tubes 63 move radially outwards thanks to the pressure exerted on these widened bases 64 by the air circulating in the internal tube 60, during the phase of expansion of said tube 60: the thrust exerted by these tubes 63 on these leaves 62, integral with said tubes, means that they move radially outwards.
In the phase of closure, in the absence of the aforementioned pressure, said leaves 62 will move radially outwards, returning into their closed position, abutting on the surface of the outermost shaft 61: in this configuration of closure it is possible to unload the reel formed previously.
Normally in the rewinding of air bubble film (or similar materials such as PE foam, XPS foam, and others) with core, spline expansion shafts are used: the Applicant has found that thanks to the combined use of leaf expansion shafts with the present wrapping assembly as defined above, and also the object of the present invention, it is possible to obtain reels of air bubble film (or similar materials such as PE foam, XPS foam, and others) without core with a continuous process performed by means of the present rewinding machine.
As mentioned previously the present rewinding machine can be provided with one single winding station and a reel unloading station, as illustrated schematically in Fig. 7, without thereby departing from the scope of protection of the present application.
In this case the rewinding machine will differ from the preceding embodiment, illustrated in Figs. 1-5, only by the type of rotating support 6, now in the form of box beam and not of vertical platform with triangular profile, since it has to support only a second leaf expandable shaft 4' (whereon a second reel B will be formed) and a first rotating leaf expandable winding shaft 4 whereon a first reel A has already formed and which now occupies the zone of the unloading station.
This box beam 6, similarly to the vertical platform of the previous embodiment, is also traversed in its central point by the horizontal rotating shaft 9 which allows this beam 6 to rotate around its centre, in a vertical plane, so as to move the first reel formed A from the winding station, at the cutting assembly 20 and wrapping assembly 30, to the unloading station placed diametrically opposite that of winding, as illustrated in Figure 7.
Even if not visible in the section of Figure 7, the opposite ends of the spindles 4, 4', attached on said box beam 6, are supported by two respective clamps 10 arranged on two respective removable arms 11 which are mounted on the rotating shaft 9 and integral therewith, similarly to the embodiment of Figures 1-5.
Moreover also in this case two fixed arms 13 are provided, each one provided at the end of an idle roller suitable for encouraging the tension of the film 3 during the rotation of the support 6 and for guiding correctly this film during this rotation. In the embodiment of Fig. 7 these fixed arms are diametrically opposite one in relation to the other and placed perpendicularly to the beam 6, even if this positioning is not binding for the purposes of the present invention.
It is to be understood that the aforementioned leaf expansion shafts 4, 4', 4" can also be used in the present machine when reels of air bubble film are to be produced (or similar materials such as PE foam, XPS foam, and others) with a core, without thereby departing from the scope of the present invention.
In this case this rewinder 100 can also be equipped with a system of loading of cardboard cores in order to produce alternatively to the reels without core also reels with cardboard core (for particular products or customers). The choice of the use or otherwise of the cardboard cores in this case is decided by the operator by means of an appropriate PLC command.
In the configuration with cardboard core the same is inserted outside of the leaf expandable spindle which subsequently is inflated in order to make the cardboard core integral therewith. The entire procedure of rewinding, cutting, extraction of reel remains the same, but the phase of unloading of the first reel A takes place simultaneously to the phase of loading of a new cardboard core in the upper section 50 (see drawings) by means of a cardboard carrying slide (not illustrated) which inserts the cardboard core on one of the spindles 4, 4', 4" currently free. After which the respective clamp 10 goes to close at the free end of the spindle while awaiting the subsequent rotation of the support platform 6 in the winding station (intermediate position of the spindle 4).
The cores are preferably loaded automatically.
It is to be understood that the present machine 100 can also be made by arranging the wrapping assembly and the cutting assembly in an opposite manner to what is illustrated in Figures 1-5 and 7, according to whether the bubbles are on the upper or lower face of the film being wound, for example, positioning the wrapping assembly above the film being wound and the cutting assembly below this film as would result from the overturning through 180° of Figure 8 with respect to the horizontal axis, without thereby departing from the spirit of the invention.
It should be noted that thanks to the fact that in the present machine the cutting is performed in co-operation with the brush and in a point of said sheet of film which is placed distant from the spindle to be wound (as described above in detail) and which does not lie on the portion of film which winds said winding shaft 4, it is possible to obtain a uniform winding even without reducing the speed of the spindle in that there is availability of a greater cut film portion with respect to other known winders which perform the cutting in proximity of the spindle.
This larger portion is represented essentially by that part of film which at the time of cutting winds the outermost roller 33 which means that it is no longer necessary to reduce the speed of winding of said winding shaft with evident advantage for the production times.
The maintaining of the constant speed of the winding shaft also at the time of cutting is also due to the fact that the aforementioned outermost roller 33 co-operates with the brush 23 in the point D (as described above) in order to facilitate further the winding of the cut flap on the winding shaft.
It should also be noted that, with respect to US 2,650,038 , the presence of at least three rollers in the wrapping assembly extending along the entire length of the spindle allows the film to be guided in a more effective manner around the spindle just immediately after the cutting, specifically when the same film has to be tightened around the spindle in order to start to wind thereon.
In fact, the three rollers of the wrapping assembly being in the form of a shaft extending longitudinally for the entire width of the film, they result, in use, completely in contact with the entire surface of said film and not in a few points as instead occurs in US 2,650,038 where the rollers have limited length since they are in the form of wheels.
This is advantageous in the winding of plastic films, generally tensioned, which, being more flexible than paper, are more mobile and more difficult to wind in an even manner along the entire length of the spindle, with the possibility of creating creases.
Numerous detail modifications and changes, within the reach of a person skilled in the art, may be made to the present embodiment of the invention, in any case coming within the scope of the invention disclosed by the annexed claims.

Claims

Automatic rewinding machine (100) for continuous in-line rewinding of a film (3) of air bubble plastic or of similar materials (such as PE foam, XPS foam, and others) in sheet form, exiting continuously from a continuous production plant, said machine comprising
a support frame (40);
an assembly of driving and tensioning of said film (3) comprising at least one first guided cylinder (1) co-operating with a second cylinder (14);
a plurality of idle cylinders (2) for accompanying the film (3) towards a winding station;
support means (6), rotating in relation to their horizontal axis, suitable for supporting one end of a respective first horizontal rotating expansion winding shaft (4) whereon a first reel A will be formed, and suitable for supporting one end of at least one second horizontal rotating expansion winding shaft (4',4"), said first and second winding shafts (4,4',4") forming, during use, at least said winding station and one reel unloading station;
means for discharging reel (8);
means (20) for cutting the film (3) being wound, comprising a mechanical arm (21) hinged to the frame (40) supporting a blade (25) suitable for only cutting the film (3) of bubble plastic (or similar materials such as PE foam, XPS foam, and others), so as to form two respective cut flaps of said sheet of film (3);
a motor-driven cylindrical brush (23) suitable for facilitating the winding of said cut flap of said sheet of film (3) on said expansion winding shaft (4, 4', 4");
said machine being characterised in that it also comprises
wrapping means (30) suitable for partially surrounding said expansion winding shaft (4,4',4") and for guiding the winding of said cut flap of said sheet of film (3) on said expansion winding shaft (4,4',4") co-operating with said motor-driven brush (23), said wrapping means (30) comprising at least three horizontal rotating rollers (31, 32, 33) extending at least for the entire length of said winding shaft (4,4',4"), the central roller (32) of said rollers (31, 32, 33) being adjacent to said winding shaft (4, 4', 4") during the cutting,
said cutting means (20) being placed opposite to said wrapping means (30) with respect to the plane formed by said sheet of film (3) being wound and in such a way, with respect to said wrapping means (30), as to cut said sheet of film (3) in a point (E) not lying on the portion of said film (3) which winds on said winding shaft (4,4',4"), said winding shafts (4,4',4") being leaf expandable shafts comprising a plurality of circular sectors (62) which move radially with respect to the axis of the respective shaft (4,4',4").
Rewinding machine according to claim 1 wherein said horizontal rotating rollers (31, 32, 33) are mounted on a hook-shaped support (35) having a portion of the profile with arched shape (39), said support (35) being hinged to a rotating mechanical arm (34) attached to the support frame (40) of the rewinding machine (100).
Rewinding machine according to claim 2 wherein said mechanical arm (34) is actuated by a first piston (36) and said hook-shaped support (35) is actuated by a second piston (37).
Rewinding machine according to any one of the preceding claims wherein said blade (25), suitable for cutting the film (3) of air bubble plastic (or similar materials such as PE foam, XPS foam, and others), is carried by a curved rod (24) hinged to said arm (21).
Rewinding machine according to any one of the preceding claims wherein said cylindrical brush (23) is carried by the other end of this arm (21).
Machine according to any one of the preceding claims wherein said mechanical arm (21) is actuated by a first piston (22) and said curved rod (24) is actuated by a second piston (27).
Machine according to any one of the preceding claims wherein said support means (6) are formed by a vertical platform or by a box beam, mounted on a horizontal rotating shaft (9) passing through its central horizontal axis.
Machine according to any one of the preceding claims wherein said rotating support means (6) support two horizontal leaf expandable winding shafts (4, 4'), diametrically opposite one to the other and forming at least one winding station and one reel unloading station.
Machine according to any one of the preceding claims from 1 to 7 wherein said rotating support means (6) support three horizontal leaf expandable winding shafts (4, 4', 4"), placed at 120° one in relation to the other and forming at least one winding station and one reel unloading station.
Machine according to any one of the preceding claims wherein the free ends of the two or three horizontal leaf expandable winding shafts (4, 4', 4") are supported by respective clamps (10) attached to respective removable arms (11), said removable arms (11) being hinged to the horizontal rotating shaft (9) of the support (6).
Process for the rewinding of a film (3) of air bubble plastic (or similar materials such as PE foam, XPS foam, and others) coming from the continuous production process, by means of the use of the rewinding machine (100) as defined in one of the preceding claims, comprising the following steps:
- winding of the film (3) on a first leaf expandable shaft (4), in expanded form to form a first reel A in a winding station;

- moving of said reel A from the winding station to the reel discharging station by rotation of said rotating support means (6);

- moving of the cutting assembly (20) and of the wrapping assembly (30) close to a second leaf expandable winding shaft (4',4") for a roll B, said shaft being placed on said rotating support means (6) in proximity of the winding station and being in contact with a portion of film (3);

- rotation of the hook-shaped support (35) of the wrapping assembly (30) in such a way that the horizontal rotating rollers (31, 32, 33) surround said second leaf expandable shaft (4',4");

- cutting of the portion of film (3) which is located between said second leaf expandable shaft (4',4"), and the outermost rotating roller (33) of the wrapping assembly (30);

- simultaneous rotation of said second leaf expandable shaft (4',4"), of said outermost rotating roller (33) and of said central roller (32) around their axis, in order to wind, on said second leaf expandable shaft (4',4"), the portion of film (3) remaining after the cutting;

- rewinding of the roll B with simultaneous discharge of the roll A.