The present invention refers to a high performance rewinding machine of extendable film.

Currently, the market offers a large amount of machines for rewinding extendable film, known in the field as "STRETCH" film.

The operation of these machines, in brief, provides that the film is unwound from a parent reel, called

"JUMBO" reel, and is wound on cardboard cores.

Such operations are carried out by two groups, respectively for unwinding and winding, which collaborate with one another.

The most common rewinding machines adopt a mechanical lever system for unwinding that carries the parent reel resting on a roller or on a belt.

It is provided for there to be a mechanical lever system for carrying cardboard tubes, or "CORES", which rests on a roller for being rewound.

These types of machines provide acceleration and deceleration ramps for the electric motor intended for being able to reach the maximum speed, wind the reel, stop the machine, cut the film, unload the finished reel, take a new cardboard tube and carry out the film "rethreading" operation.

In such machines, after each "Jumbo" reel has been unwound, the worker must manually replace the finished reel with a new one.

All the cycle operations described above are carried out in operating conditions in which the machine is stopped with a consequent loss in terms of production, whereas the acceleration and deceleration step leads to a considerable consumption of electric energy.

The most advanced rewinding machines adopt a better performing rewinding system that makes it possible to not slow down the machine when changing the reel being wound .

Such machines, in any case, have different downtime, due to the need of carrying out some mechanical movements that are necessary in order to allow the finished reel to be unloaded and the new cardboard tube to be loaded.

All this leads to a consequent waste of time, which limits the machine to having relatively low speed and production .

Also in the case of these better performing machines, after each "Jumbo" reel has been unwound the worker must in any case replace the finished reel with a new one, when the machine is stopped, with consequent deceleration-acceleration ramp, that despite being smaller with respect to common rewinding machines, always leads to a loss in terms of production and to unnecessary waste of electrical energy.

Starting from such a prior art, the purpose of the present invention is that of making a rewinding machine of extendable film that is alternative to those known, that is particularly efficient and that is capable of increasing production.

According to the general aspect of the present invention, the rewinding machine described and claimed here provides an unwinding group that is capable of automatically unloading the finished "Jumbo" reel and of loading a new one without stopping the machine. Moreover, also the winding group provides for unloading the finished reels without providing the winding group itself stopping.

Further characteristics of the present invention shall be highlighted by the dependent claims.

The characteristics and the advantages of a rewinding machine of extendable film according to the present invention shall become clearer from the following description, given as an example and not for limiting purposes, with reference to the attached schematic drawings, in which:

figure 1 shows a perspective schematic view of a winding group for a rewinding machine of extendable film according to the present invention;

- figure 2 shows a schematic side view of the winding group of figure 1; and

figure 3 shows a schematic split view of the unwinding group for a rewinding machine of extendable film according to the present invention.

With reference to the figures, an unwinding group for a rewinding machine of extendable film according to the present invention is shown with reference numeral 10 and the relative winding group is shown with reference numeral 100.

Such a rewinding machine of extendable film is of the type comprising an unwinding group 10 of a parent reel and a winding group 100 on cores of the film unwound from said parent reel.

In particular, the unwinding group 10 comprises a rod 11 that is provided with a first end of a first shaft 12 for loading a first parent reel 13 and with a second end of a second shaft 14 for loading a second parent reel 15.

Such a rod 11 is hinged 16 so as to allow the cyclical rotation R between:

- a first position in which said first shaft 12 is outside said unwinding group 10 and is free to receive said first parent reel 13 while said second shaft 14 is inside said unwinding group; and

- a second position in which said second shaft 14 is outside said unwinding group 10 so as to reload a new parent reel and said first shaft 14 is inside said unwinding group 10.

The passage from said first to said second position is made continuously during the winding of film in said winding group 100.

Moreover, the unwinding group 10 comprises a press element 17 that is mobile so as to allow the second parent reel to be replaced with the first one without interruptions in the winding, such a press element 17 also comprising means for cutting the film.

The winding group 100, on the other hand, comprises a revolver-like horizontal structure that is provided with one end of a spindle holder 102 disc 101 carrying shafts 103 for receiving winding cores.

At a second end the revolver comprises a vertical lever assembling group 105 mobile on a ring 104 so that, during the rotation of said revolver, said levers are coupled with said spindles only for one portion T of the rotation so as to allow the winding, the loading and unloading of the cores at a high frequency.

For such a purpose a guide 106 is provided associated with said second end and that is configured to bring said levers 105 into a position for coupling with said spindles during the rotation of the revolver.

The rotation is driven by a drive shaft 110 that is moved by an electric motor for the rotation of the ends of said winding group 100.

It should be clear how a rewinding machine of extendable film of the present invention operates.

As can be seen from the description above, the rewinding machine of the present invention has innovative technical solutions in terms of mechanics and automation for solving the problems such as production speed, minimisation of the downtime and of consumption of electrical energy.

Relative to the unwinding group, this is completely automated and the operator has the single task of loading the "jumbo" onto an automatic trolley that is waiting .

Such an operation occurs during the operation step of the machine and therefore it does not cause time to be wasted with the consequent lack of production.

The changing cycle of the parent reel occurs quickly with a pressure roller system.

In a particular way the film of the new reel is attached to the film of the old one with a gluing system and/or through electrostatic charge.

Concerning the winding group, the innovative arm system for holding "tailstocks-spindles" make it possible to reduce to one third the normal cycle times required by the higher performing machines on the market today with the consequent possibility of accelerating the production to levels that have never been seen before and obtaining a finished product of excellent quality. Whereas on the common "REVOLVER" winders the cycle occurs through stepped rotations of two discs sometimes simultaneously and sometimes delayed, in the present invention the rotation is always continuous.

The steps of known machines, indeed, provide the release of the tailstocks, the rotation of the single disc that carries tailstocks so as to allow the finished reel to be unloaded and the new core to be loaded, the rotation of the single disc holding tailstocks so as to be brought back into position "0" and to pneumatically close the tailstocks.

Contrarily, our new winding group according to the invention has a single spindle holder disc and a system of tailstock bearing levers opposite it that, mechanically, during rotation, move into a neutral position so as to facilitate and speed up the unloading of the finished reel and the loading of the new core to the maximum.

In other words the tailstocks open up simultaneously during the rotation thus minimising the cycle times and thus allowing the users to have much greater production .

It has thus been seen that a rewinding machine of extendable film according to the present invention achieves the purposes previously highlighted.

The rewinding machine of extendable film of the present invention thus conceived can undergo numerous modifications and variants, all covered by the same inventive concept; moreover, all the details can be replaced by technically equivalent elements. In practice the materials used, as well as the dimensions, can be o f any type according to the technical requirements .