Device for feeding and cutting film in machines for conditioning products

Abstract

A device for feeding and cutting a continuous film ( 2 ) to a station ( 5 ) for wrapping products ( 4 ) is applied to a conditioning machine or line ( 3 ) comprising a station ( 6 ) for positioning and feeding products ( 4 ) which are mobile, one after another and in a direction of feed (V), on a conveyor surface ( 7 ) along the machine ( 3 ) between the positioning station ( 6 ) and the wrapping station ( 5 ). The film ( 2 ) is located between the surface ( 7 ) and the base ( 4 a ) of the products ( 4 ), where they pass close to a first slot ( 25 ) in the conveyor surface ( 7 ), and the film ( 2 ) proceeds as one with the products ( 4 ) along the surface ( 7 ). The conditioning line ( 3 ) also comprises cutting means ( 13 ) for forming a piece ( 2 a ) of film ( 2 ), these means being located at the conveyor surface ( 7 ), downstream of the first slot ( 25 ) and upstream of the wrapping station ( 5 ) according to the direction of feed (V). The cutting means ( 13 ) operate at the gap between successive products ( 4 ).

1 ) A device for feeding and cutting a continuous film ( 2 ) to a station ( 5 ) for wrapping products ( 4 ) in a conditioning machine or line ( 3 ) comprising a product ( 4 ) positioning and feed station ( 6 ), the products ( 4 ) being mobile, one after another and in a direction (V) of feed, on at least one conveyor surface ( 7 ) along the machine ( 3 ) between the positioning station ( 6 ) and the wrapping station ( 5 ), the film ( 2 ) being located between the surface ( 7 ) and the base ( 4   a ) of the products ( 4 ), where the products pass close to a first slot ( 25 ) in the conveyor surface ( 7 ) and proceeding as one with the products ( 4 ) along the surface ( 7 ), the device comprising cutting means ( 13 ) for forming a piece ( 2   a ) of film ( 2 ), the cutting means being located at the conveyor surface ( 7 ), downstream of the first slot ( 25 ) and upstream of the wrapping station ( 5 ) according to the direction (V) of feed, the cutting means ( 13 ) operating at the gap between successive products ( 4 ).  
   
   
       2 ) The device according to  claim 1 , comprising return means ( 10   a ) forming a second slot ( 11 ) in the conveyor surface ( 7 ) for the passage of a knife ( 13 ), transversally mobile relative to the conveyor surface ( 7 ), and forming the cutting means ( 13 ).  
   
   
       3 ) The device according to  claim 1 , comprising return means ( 10   a ) forming a second slot ( 11 ) in the conveyor surface ( 7 ) for the passage of a knife ( 13 ), transversally mobile relative to the direction (V) of feed and forming the cutting means ( 13 ).  
   
   
       4 ) The device according to  claim 2 , comprising presser means ( 21 ) located at the cutting means ( 13 ), on opposite sides of the cutting means ( 13 ), to block and hold the film ( 2 ) relative to the cutting means ( 13 ) for formation of the piece ( 2   a ) of film.  
   
   
       5 ) The device according to  claim 4 , wherein at least the cutting means ( 13 ), the return means ( 10   a ) and the presser means ( 21 ) are mobile along the direction (V) of feed, parallel with the conveyor surface ( 7 ) and simultaneously with the products ( 4 ) and the film ( 2 ), from a start of stroke position, where a cut in the film ( 2 ) begins, to an end of stroke position, where the cut finishes.  
   
   
       6 ) The device according to  claim 4 , wherein at least the cutting means ( 13 ), the return means ( 10   a ) and the presser means ( 21 ) are mobile along the direction (V) of feed, parallel with the conveyor surface ( 7 ) and with a speed (V 1 ) different to the speed (V 2 ) of the products ( 4 ) and of the film ( 2 ), from a start of stroke position, where a cut in the film ( 2 ) begins, to an end of stroke position, where the cut finishes.  
   
   
       7 ) The device according to  claim 5 , comprising a carriage ( 43 ), supporting the cutting means ( 13 ), the return means ( 10   a ) and the presser means ( 21 ), and a first guide ( 44 ) extending along the machine ( 3 ), the carriage ( 43 ) being slidably connected to the guide ( 44 ).  
   
   
       8 ) The device according to  claim 4 , wherein the presser means ( 21 ) comprise at least one pneumatic piston ( 21 ) designed to control at least one pair of fork-shaped pads ( 21   a ).  
   
   
       9 ) The device according to  claim 1 , wherein at the surface ( 7 ) there are second presser means ( 100 ) acting on the film ( 2 ), downstream of the slot (N) relative to the direction (V) of feed, and designed to allow the film ( 2 ) to be held in the absence of the products ( 4 ) on the surface ( 7 ).  
   
   
       10 ) The device according to  claim 1 , including a reel ( 22 ) supporting the film ( 2 ) and means ( 24 ) for unwinding the film ( 2 ) from the reel ( 22 ), comprising safety means ( 32 ), located downstream of the reel ( 22 ) according to a direction (S 1 ) of film ( 2 ) unwinding, to prevent film ( 2 ) tensioning when the film is unwound simultaneously with feeding of the products ( 4 ) on the conveyor surface ( 7 ), downstream of the first slot ( 25 ), the products pulling the film ( 2 ) along the surface ( 7 ).  
   
   
       11 ) The device according to  claim 10 , wherein the safety means ( 32 ) comprise at least a first unit ( 28 ) designed to form a reserve ( 31 ) of film ( 2 ) downstream of the reel ( 22 ) according to the direction (S 1 ) of unwinding.  
   
   
       12 ) The device according to  claim 11 , wherein the first unit ( 28 ) operates by emitting fluid to create a loop ( 30 ) in the film ( 2 ), the loop ( 30 ) forming the reserve ( 31 ).  
   
   
       13 ) The device according to  claim 10 , wherein the safety means ( 32 ) comprise a sonar ( 27 ) opposite the film ( 2 ), for detecting film ( 2 ) tensioning.  
   
   
       14 ) The device according to  claim 1 , comprising sensor means ( 33 ) located along a film ( 2 ) unwinding path (S) designed to operate in conjunction with, respectively, the positioning and feed station ( 6 ), to form a group ( 38 ) of products ( 4 ), and with the cutting means ( 13 ) and the conveyor surface ( 7 ), to form the piece ( 2   a ) of film.  
   
   
       15 ) The device according to  claim 14 , in which the film ( 2 ) has a reference element in predetermined sequences, wherein the sensor means ( 33 ) comprise at least a first photocell ( 34 ) for identifying the reference element, aligned with the film ( 2 ), located upstream of the first slot ( 25 ), according to a direction (S 1 ) of film ( 2 ) unwinding ( 2 ), for checking synchronization between the film ( 2 ) and the size of the products ( 4 ) in transit, close to the first slot ( 25 ) so as to allow centering of the film ( 2 ) and the group ( 38 ) of products ( 4 ).  
   
   
       16 ) The device according to  claim 15 , wherein the first photocell ( 34 ) is mobile along a second guide ( 35 ), extending parallel with the film ( 2 ), between a first position, corresponding to a minimum size of the piece ( 2   a ) of film and a second position, corresponding to a maximum size of the piece ( 2   a ) of film.  
   
   
       17 ) The device according to  claim 14 , wherein the sensor means ( 33 ) comprise a second photocell ( 36 ) located at the conveyor surface ( 7 ), downstream of the first slot ( 25 ) and upstream of the cutting means ( 13 ) according to a direction (V) of feed, forming the size of the group ( 38 ) of products ( 4 ) on the conveyor surface ( 7 ), operating in conjunction with a separator element ( 37 ) of the positioning and feed station ( 6 ).  
   
   
       18 ) The device according to  claim 17 , wherein the second photocell ( 36 ) is mobile on a third guide ( 39 ) between a position distanced from the cutting means ( 13 ) and a position close to the cutting means ( 13 ) forming respective sizes.  
   
   
       19 ) The device according to  claim 14 , in which the film ( 2 ) is of the transparent type, wherein the sensor means ( 33 ) comprise a third photocell ( 40 ) located close to the conveyor surface ( 7 ), downstream of the cutting means ( 13 ) and upstream of the wrapping station ( 5 ) according to the direction (V) of feed, to establish a length, that is to say the size, of the piece ( 2   a ) of film for wrapping the group ( 38 ).  
   
   
       20 ) The device according to  claim 19 , wherein the third photocell ( 40 ) is mobile on a fourth guide ( 41 ), extending parallel with the film ( 2 ), between a minimum size position, corresponding to a minimum size of the piece ( 2   a ) of film and a maximum size position, corresponding to a maximum size of the piece ( 2   a ) of film.  
   
   
       21 ) The device according to  claim 1 , comprising a fourth photocell ( 42 ) located immediately upstream of the cutting means ( 13 ) according to the direction (V) of feed, for checking alignment of the products ( 4 ) and the film ( 2 ) with the cutting means ( 13 ).