Apparatus for packaging a product with an extensible film

Abstract

An apparatus for packaging a product with an extensible film, including a conveyor for conveying a product to the apparatus, an evacuating device for evacuating a product from the apparatus at the end of packaging, an unwinding device to unwind the extensible film from a reel mounted on the apparatus, a tensioning device for tensioning the extensible film, the unwinding device including a first gripping element and a second gripping element that are movable independently of one another in an unwinding direction for unwinding the extensible film from the reel.

1 - 17 . (canceled) 
     
     
         18 . An apparatus for packaging a product with an extensible film, comprising a conveyor for conveying a product in the apparatus, an evacuating device to evacuate the product from the apparatus at the end of packaging, an unwinding device to unwind the extensible film from a reel mounted on the apparatus, a tensioning device for tensioning said extensible film, a lifting device intended for receiving the product from said conveyor and lifting the product to bring the product into contact with said extensible film, said unwinding device comprising a first gripping element and a second gripping element that are movable independently of one another in an unwinding direction for unwinding the extensible film from the reel, said first gripping element comprising a first fixed jaw and a first movable jaw, one end of the first movable jaw being provided with a plurality of first teeth, arranged in a comb configuration, said second gripping element comprising a second fixed jaw and a second movable jaw, one end of the second movable jaw being provided with a plurality of second teeth, arranged in a comb configuration, wherein said lifting device is provided with a plurality of parallel grooves, oriented in a direction parallel to said unwinding direction and dimensioned so that the first teeth of the first movable jaw of said first gripping element and the second teeth of the second movable jaw of said second gripping element can be inserted into said grooves. 
     
     
         19 . The apparatus according to  claim 18 , wherein said tensioning device comprises a third gripping element and a fourth gripping element that are movable independently of one another in a direction that is perpendicular to said unwinding direction. 
     
     
         20 . The apparatus according to  claim 18 , wherein said second gripping element comprises a second fixed jaw and a second movable jaw, one end of the second movable jaw being provided with a plurality of second teeth, arranged in a comb configuration. 
     
     
         21 . The apparatus according to  claim 20 , wherein said first teeth and said second teeth are arranged staggered in relation to one another, so as to be able to be inserted into one another, when said first movable jaw and said second movable jaw are brought into contact with one another. 
     
     
         22 . The apparatus according to  claim 19 , wherein said third gripping element comprises a third fixed jaw and a third movable jaw, said third movable jaw comprising a plurality of sections that are separate from one another. 
     
     
         23 . The apparatus according to  claim 19 , wherein said fourth gripping element comprises a fourth fixed jaw and a fourth movable jaw, said fourth movable jaw comprising a plurality of sections that are separate from one another. 
     
     
         24 . The apparatus according to  claim 18 , wherein said conveyor comprises a sliding surface on which a product to be packaged can be slid and two pushing elements each of which is driven by a first belt and by a second belt moved by a first motor. 
     
     
         25 . The apparatus according to  claim 18 , wherein said conveyor comprises a weighing device. 
     
     
         26 . The apparatus according to  claim 24 , wherein an end portion of said sliding surface is provided with a plurality of protrusions arranged in a slightly arched configuration. 
     
     
         27 . The apparatus according to  claim 18 , wherein said evacuating device comprises a motor-driven band made of a heat-resistant material, said motor-driven band being heated by a heater. 
     
     
         28 . The apparatus according to  claim 27 , and further comprising a further pushing element intended for pushing a product packaged on said motor-driven band. 
     
     
         29 . The apparatus according to  claim 18 , wherein the movements of the second gripping element and of the first gripping element during packaging of said product determine the quantity of extensible film that is unwound from the reel for said packaging operation and the quantity of extensible film that is used in said packaging operation, respectively. 
     
     
         30 . A method for packaging a product with an extensible film, comprising:
 unwinding a portion of extensible film from a reel by a first gripping element and a second gripping element, said portion having a length depending on the dimensions of the product to be packaged;   tensioning said extensible film by grasping opposite edges of said extensible film by a third gripping element and a fourth gripping element;   placing said product, or a tray containing the product on a lifting device;   bringing said product into contact with a lower face of said extensible film via a lifting device, raising the lifting device until the lower part of the product or of the tray reaches the level of said gripping elements, wherein it further comprises:   bringing two flaps of film retained by the first gripping element and by the second gripping element under the lower part of the product, or of the tray, inserting the first gripping element and the second gripping element between said lifting device and the product or the tray so that they support the product or the tray, said flaps being pressed against the lower part of the product or of the tray to adhere to said lower part or to said tray;   bringing two further flaps of film retained by the third gripping element and by the fourth gripping element under the lower part of the product, or of the tray, inserting the third gripping element and the fourth gripping element under the product or the tray said further flaps being pressed against the lower part of the product or of the tray to adhere to said lower part or to said tray.   
     
     
         31 . The method according to  claim 30 , and further comprising the step of superimposing on one another said flaps of film for a portion in a position that is central to the product, or to the tray. 
     
     
         32 . The method according to  claim 30 , and further comprising the step of superimposing on one another said flaps of film for a portion in a position that is off-center with respect to the product, or to the tray. 
     
     
         33 . The method according to  claim 30 , and further comprising the step of superimposing at least a portion of said further flaps on one another. 
     
     
         34 . The method according to  claim 30 , and further comprising comprising superimposing said further flaps on said flaps and welding together said flaps and said further flaps.