Patent Publication Number: US-11046471-B2

Title: Cutting unit for a packaging machine in extendable film

Description:
The present invention relates to a cutting unit in a packaging machine with extendable film. 
     The field of application relates to the packaging of products, for example bottles, in films made of plastic material to form bundles for their storage and transportation, also by the end-user. 
     Currently, in this specific field of the packaging of various types of products, such as, for example, bottles, boxes of various sizes, etc., a film of heat-shrinkable plastic material is mostly used. This film is wrapped around the product or group of products and a single package is then separated by means of a rather complex cutting device. This package is then treated in a heat-shrinking oven which makes it stable, thus stably withholding the products contained therein. 
     This heat-shrinkable plastic material has a certain thickness and cost and furthermore requires a further additional step, with relative oven, for treating it with heat to cause its heat-shrinkage. 
     If, alternatively, a film of extendable plastic material is used for the packaging, spirally wrapped around the products that are moved forwards according to a horizontal direction, the cutting step is more complicated and difficult due to the characteristics of this film. 
     If, on the one hand, a packaging in film of extendable plastic material eliminates the need for a heat-shrinking oven and relative energy costs and allows the use of a thinner film, at present, the cutting device used is not satisfactory as it requires various steps and unsustainably slows down the final packaging. 
     WO 2015/040565 describes a cutting unit for a packaging machine for separating a series of finished packages containing a predetermined number of products, from a continuous bundle advancing on a conveyor. 
     The general objective of the present invention is to provide a cutting unit in a packaging machine of products in extendable film which is able to solve the drawbacks of the known art indicated above in an extremely simple, economical and particularly functional manner. 
     A further objective of the present invention is to provide a cutting unit suitable for being inserted in a packaging machine, which can eliminate slow-downs in the packaging, increasing the production of finished packages. 
     Another objective of the present invention is to provide a cutting unit for a packaging machine of products in extendable film which is able to reduce the costs relating to the packaging material. 
    
    
     
       The structural and functional characteristics of the present invention and its advantages with respect to the known art will appear even more evident from the following description, referring to the enclosed schematic drawings which show an embodiment example of the invention itself. In the drawings: 
         FIG. 1  is a perspective view in which a cutting unit according to the present invention is provided, suitable for being inserted in a packaging machine of products in extendable film; 
         FIG. 2  is a perspective view of the unit shown in  FIG. 1  as it appears from a position at 180° with respect to the previous view with the blades open in a rest position; 
         FIG. 3  is a sectional view of the cutting unit in a side cutting position of a continuous bundle of bottles; 
         FIG. 4  is a sectional view of the cutting unit with the upper and lower blades in a cutting position of the continuous bundle of bottles; 
         FIG. 5  is a perspective view of a package produced with the cutting unit shown in the previous figures according to the present invention; 
         FIGS. 6 and 7  are a perspective view and a cross-section of a second embodiment of a cutting unit according to the invention. 
     
    
    
     With reference to  FIGS. 1-4 , these show a cutting unit according to the present invention which can be inserted in a final portion of a packaging machine in extendable film, of products  11 , such as bottles or other objects, not shown, and, for example, of the type described in Italian patent applications Nr. 102016000012911 and 102016000013038 of the same Applicant. 
     In general, the single products, such as bottles  11 , are ordered upstream of a wrapping station in which the same are arranged inside a continuous film  15  wrapped around products  11  with a single turn or crossed turns according to the directions  12 ,  13 , indicated in  FIG. 5 , to form a continuous bundle. This continuous packaging or bundle therefore comprises two layers of film wrapped in opposite directions around these products  11 . 
     In the case of bottles  11 , for example, said bottles  11  are fed in flanked pairs moved forwards on a lower feeding conveyor, schematized with the line  14  until entering, thus wrapped, the cutting unit. 
     Said continuous bundle then passes into the unit of the present invention fed on a normal conveyor  14 , for example with a belt or rollers. 
     It should be noted how these products  11  are, for example, contained wrapped in an extendable film in an intersection of film layers arranged so as to stabilize the package when finished. 
     As already mentioned, this cutting unit according to the invention separates the continuous bundle or packaging into finished groups of products  11 , wrapped in film of extendable plastic material and forming a final package  16 , after cutting. 
     A cutting unit according to the invention must intervene in a packaging machine for separating, from a continuous packaging or bundle moving forwards, a series of finished packages  16  of a predetermined number of products  11 , shown in  FIG. 5  as six bottles  11  flanked in pairs. 
     It can thus be seen how the package has side-cut areas and upper and lower horizontal-cut areas in correspondence with the cutting. 
     The cutting unit comprises a frame  20  that supports a pair of side cutting blades  21  and a pair of upper cutting  22   s  and lower cutting  22   i  blades arranged facing four sides of the continuous bundle. 
     The four blades  21 ,  22   s  and  22   i  can be alternately moved forwards and backwards between a rest position separated from the continuous bundle and an engagement position on the continuous bundle containing groups of products  11 , wrapped in a film of extendable plastic material  15 . 
     The two side cutting blades  21  are arranged vertically and are driven in an alternating forward and backward movement for engagement and disengagement from the continuous bundle by means of a double crank  23 ,  23 ′. The double crank  23 ,  23 ′ is actuated by a single motor  24  which drives relative slides  25  horizontally movable with respect to the frame  20  and carrying said cutting blades  21 . 
     The upper cutting blade  22   s  and lower cutting blade  22   i  are also carried by relative slides  26  which can be moved vertically with respect to the frame  20 . 
     The slides  26  can be moved vertically by means of a second double crank  27 ,  27 ′ which is also actuated by a single motor  28 . 
     The frame  20 , in fact, causes a pair of slides  26  to move upwards and downwards, each slide carrying the upper cutting blade  22   s  and the lower cutting blade  22   i  respectively. 
     Furthermore, the frame  20  is moved forwards to “follow” the continuous bundle of bottles, advancing at the same rate, from which a single bundle must be formed. This “tracking” is effected for a length so as to allow both the side cutting blades  21  and the upper cutting blade  22   s  and lower cutting blade  22   i  to intervene on the continuous bundle and separate a finished package  16 . 
     After separating the packaging, the cutting unit according to the invention on its frame  20  returns rapidly back to the continuous bundle to separate a new packaging  16 . 
       FIGS. 6 and 7  show a further example of a cutting unit according to the invention. 
     In this example, functionally equal elements are indicated with the same reference numbers as the previous example of  FIGS. 1-4 . 
     Also in this example, two side cutting blades  21  are provided, which are also arranged vertically. 
     The two cutting blades are driven in an alternating forward and backward movement for engagement and disengagement from the continuous bundle by means of the above-mentioned double crank  23 ,  23 ′. Also in this case, the double crank  23 ,  23 ′ is actuated by a single motor  24  which controls the slides  25  that carry the two side cutting blades  21 . 
     Otherwise, an upper cutting blade  22   s ′ and a lower cutting blade  22   i ′ are provided, carried by relative slides  26  that are vertically movable with respect to the frame  20 . Said slides can also move vertically through a second double crank  27 ,  27 ′ actuated by a single motor  28 . 
     In this case, the upper cutting blade  22   s ′ and the lower cutting blade  22   i ′ provide an amplitude slightly less than the transversal dimension of the packaging  16  and act in a recessed area  17  between consecutive pairs of bottles  11 . 
     This reduced dimension allows a simultaneous action between the two side cutting blades  21  and the upper cutting blade  22   s ′ and lower cutting blade  22   i ′, as shown in  FIGS. 6 and 7 . 
     This is achieved by a common drive of the motor  24  and the motor  28  for actuating both of the crank mechanisms  23 ,  23 ′ and  27 ,  27 ′. This simultaneous actuation causes an action of the four blades  21 ,  22   s ′ and  22   i ′ on the continuous bundle. 
     Also in this case, despite the reduced time of this cutting operation, the action of the cutting unit is effected while the frame  20  is moved forwards to “follow” the continuous bundle of bottles from which the single bundle is to be separated. Once the cutting has been completed, said frame  20  of the cutting unit is then brought back onto the continuous bundle ready to separate a new packaging  16 . 
     In a further embodiment, the cutting unit comprises cutting elements arranged on the frame in the form of hot wires instead of blades. These hot wires are used both as side, upper and lower cutting elements. These cutting elements can also be moved alternately between a rest position separated from the continuous bundle and an engagement position on the bundle. 
     According to the invention, therefore, this particular cutting unit acts on the continuous packaging of plastic material wrapped around the bottles  11  to make a cut on four sections of the packaging, two vertical and two horizontal, which thus form the perimeter of the transverse cutting of the package as shown in  FIG. 5 . 
     The functioning of a cutting unit according to the invention in a packaging machine in extendable film of products fed in continuous is as follows. 
     Once a continuous packaging or bundle containing products, such as pairs of bottles, has been produced in the packaging machine, said packaging is sent to the cutting unit. 
     This continuous packaging or bundle of pairs of bottles  11 , produced for example with crossed layers of extendable film but not exclusively in this way, passes onto the lower conveyor  14 . The conveyor  14  supports and accompanies the continuous packaging or bundle in the cutting unit during the complete cutting phase. 
     The whole cutting unit carried by the frame  20  and carrying the side cutting blades  27  and upper cutting blade  22   s  and lower cutting blade  22   i , moves according to the same advance rate as the continuous bundle containing the bottles  11 . 
     In a cutting unit according to the invention, the cutting is effected during the advancement phase of the bundle and frame of the cutting unit at the same rate and is terminated when the frame or cutting unit is moved back when the packaging is finished. 
     It has previously been seen how, both in the first example and in the second example, the cutting unit interacts with the layers of film of the continuous bundle on horizontal sections and on vertical sections of the continuous packaging or bundle, causing the separation of the packaging  16 . 
     The cutting times with respect to known devices in which vertically cut sections are produced, followed by horizontally cut sections or viceversa in two consecutive steps both at the top of the packaging and at the end of the packaging, are halved. 
     Furthermore, a direct action in a single advancement phase of the cutting unit ensures perfect alignment between horizontal cuts and vertical cuts. 
     A correct cutting of the continuous bundle of finished packages  16  of the required size, is thus obtained. 
     As in the known systems, this type of cut defined as “perimetric” transverse to the packaging, involves short strokes of the blades in extremely reduced times. 
     The objective mentioned in the preamble of the description has therefore been advantageously achieved. A cutting unit is provided with particularly reduced intervention times. 
     Furthermore, using extendable plastic material, no heat-shrinking is necessary, with a considerable energy saving. 
     More than one cutting unit within a packaging machine can also be provided, for example, with an increase in the hourly productivity. 
     The forms of the structure for producing a cutting unit of the present invention, as also the materials and assembly modes, can naturally differ from those shown as a purely non-limiting example in the drawings. 
     The protection scope of the present invention is defined by the enclosed claims.