Process and machine for winding thermoplastic film in bobbins of chosen size

Abstract

A process for the continuous winding, with an automatic cycle, of thermoplastic film in bobbins of a chosen size directly from the film production apparatus or from large bobbins, wherein the wound bobbin, by means of automatic operations, is unloaded from the working seat (after cutting the film being wound), the spindle of the cardboard core-spindle assembly is deflated of air, the bobbin is removed from the spindle and the spindle is inserted in a new cardboard core and then inflated with air in order to rigidly couple the cardboard core with the spindle, and finally the new cardboard core-spindle assembly, after spraying onto the cardboard core a film of glue for the adhesion of the film, is placed in standby, waiting to be inserted in the working seat in order to begin the winding of a new bobbin.

What is claimed is:  
     
         1 . A process for the continuous winding, with an automatic cycle, of thermoplastic film so as to obtain bobbins of chosen diameter and size directly in line with the film production system or starting from large bobbins in order to obtain smaller bobbins, comprising the following steps, performed sequentially starting from a bobbin after completing the winding step: 
 1) disengagement from the working seat of the cardboard core-spindle assembly on which the bobbin is wound:    2) deflation of the air from the spindle;    3) removal of the bobbin from the spindle;    4) fitting of a new cardboard core on the spindle;    5) inflation of the spindle with air;    6) positioning of the new spindle-cardboard core block in the standby seat before the new winding step, in which: 
 during step 1), the connecting rod that supports the spindle on the cardboard core of which the bobbin is being wound in contact with the roller, after completing the winding and after cutting the film, reaches a vertical position, while the carriage, which has a horizontal translational motion along the horizontal guide and a vertical motion along the vertical guide, is in a standby position below the bobbin when the connecting rod reaches the vertical position; the carriage then rises, sliding on the guide, until the bobbin is positioned on the cradle, which is rigidly coupled to the carriage, and performs a further upward translational motion, lifting the spindle-bobbin assembly, releasing it from the connecting rod, which can return to the working position;  
 during step 2), the deflation unit arranged on the horizontal guide in axial alignment with the spindle is actuated so as to discharge the air from the spindle;  
 during step 3), the carriage, after the deflation assembly has returned to its position, performs an outward translational motion on the horizontal guide, while the spindle remains locked by the support, causing the extraction of the bobbin, which is collected in the cradle;  
 during step 4), the carriage, as it continues its translational motion along the horizontal guide, engages the microswitch, which provides the clearance signal for the actuation of the connecting rod assembly so as to support the spindle when the bobbin drawn by the cradle is extracted fully from the spindle; the carriage continues in its translational motion until it lies below the cardboard core loading assembly, from which the cardboard cores are arranged by gravity on the cradle, previously freed of the bobbin; it then moves upward along the guide, so as to align the axis of the cardboard cores with the axis of the spindle for the insertion of a cardboard core by virtue of a translational motion of the cradle (during the translational motion of the cradle, the cardboard cores are sprayed with a film of glue in order to ensure the adhesion of the film to the cardboard core when the winding step begins);  
 during step 5), the carriage is moved upward until it moves beyond the spindle loading assembly, which is provided with the arm, which opens so as to support the spindle; then the carriage descends so as to return to the cycle start position, thus allowing the spindle to be deposited on the arm, from which the spindle then slides toward the inflation assembly, since the spindle loader is slightly inclined with respect to the winding unit;  
   during step 6), once inflation has been performed, the spindle continues its descent until it reaches the chain, by which the spindle is placed in its working seat in contact with the roller when it requires a new spindlecardboard core for a new winding step.    
     
     
         2 . The process according to  claim 1 , wherein a series of bobbins is wound in line with the film production system.  
     
     
         3 . The process according to  claim 1 , wherein the bobbins are wound onto cardboard cores having a diameter of 38, 50 and/or 76 mm and a length between 400 and 530 mm.  
     
     
         4 . The process according to  claim 1 , wherein the position of the movements of the carriage along the guides and is set by microswitches, while the actuation of the various connecting rods that operate in the process, the fall of the cardboard cores from the cardboard core loading assembly, their supply in said assembly, and the step for positioning the spindles on the arm are provided by means of pneumatic pistons.  
     
     
         5 . A machine for winding thermoplastic film according to the process of  claim 1 , comprising: a connecting rod for positioning a spindle on which the bobbin, wound in contact with the roller, is fitted; a carriage, which has a horizontal translational motion and a vertical translational motion by sliding respectively on the guides and performs the movements required to provide the various steps of the winding cycle; an assembly for deflating/inflating the air from and in the spindle; an assembly for supporting the spindle during its extraction from the bobbin; a cradle for collecting the wound bobbins and then the cardboard cores for their fitting on the spindles; and an assembly for positioning the cardboard core-spindle assemblies while waiting to start a new cycle.