Product wrapping machine and operating method for a product wrapping machine

Abstract

A product wrapping machine with a plurality of counter-jaws homogenously distributed in a forward movement direction (X), a plurality of jaws moving perpendicular to the forward movement direction (X) from an open position to a closed position against the counter-jaws for sealing together the films wrapping the product to one another and cutting them. The machine also includes a jaw actuator for each jaw causing the corresponding jaw to move in the closing direction. The jaws move together simultaneously in the forward movement direction (X) and move independently from one another in the closing direction. The machine further includes a tensioner suitable for collecting part of the film wrapping the product when a jaw leaves the closed position.

What is claimed is: 
     
         1 . A method for wrapping a product in a film by use of a machine comprising at least first and second spaced-apart transverse counter-jaws and at least first and second spaced-apart transverse jaws, each of the first and second transverse jaws moveable independently with respect to the first and second transverse counter-jaws, respectively, between an open position wherein the first and second transverse jaws are spaced apart from the respective first and second transverse counter-jaws and a closed position wherein the first and second transverse jaws interact with the respective first and second transverse counter-jaws, the method comprising:
 arranging a first film on or adjacent the first and second transverse counter-jaws,   positioning the product in a space between the first and second transverse counter-jaws so that a lower portion of the product is in contact with the first film,   moving the product with the first and second transverse counter-jaws in a forward movement direction during which a second film is arranged on an upper portion of the product, each of the first and second transverse jaws being moved together in the forward movement direction so as to be aligned with the first and second transverse counter-jaws, respectively,   moving the first transverse jaw from the open position to a closed position to join and then cut the joined first and second films adjacent a first side of the product while maintaining the second transverse jaw in the open position,   moving the first transverse jaw from the closed position to the open position,   while the first and second transverse jaws are open, applying a tension to the second film in a direction having a directional component opposite the forward movement direction to collect a part of the second film; and   subsequent to applying the tension to the second film, moving the second transverse jaw from the open position to a closed position to join and then cut the joined first and second films adjacent a second side of the product while maintaining the first transverse jaw in the open position.   
     
     
         2 . A method according to  claim 1 , wherein sufficient tension is applied to the second film to remove the wrapped film from the first transverse counter-jaw. 
     
     
         3 . A method according to  claim 1 , wherein the step of moving the first transverse jaw from the open position to the closed position to join and then cut the joined first and second films adjacent the first side of the product results in a space being formed between at least a portion of the joined first and second films and the first side of the product, the tension being applied to the second film in a manner sufficient to reduce or remove the space. 
     
     
         4 . A method according to  claim 2 , wherein subsequent to moving the second transverse jaw from the open position to the closed position to join and then cut the joined first and second films adjacent the second side of the product the product is moved away from an upper portion of the second transverse counter-jaw to detach the wrapped film from the second transverse counter-jaw. 
     
     
         5 . A method according to  claim 4 , wherein an actuator acts on the lower portion of the product to cause the product to be moved away from the second transverse counter-jaw. 
     
     
         6 . A method according to  claim 4 , wherein the distance between the product and upper portion of the second transverse counter-jaw is increased by increasing the separation distance between the upper portions of the first and second transverse counter-jaws. 
     
     
         7 . A method according to  claim 5 , wherein increasing the separation distance of the first and second transverse counter-jaws is done by causing the first and second transverse counter-jaws to rotate in opposite directions. 
     
     
         8 . A method according to  claim 1 , wherein the product is continuously moved in the forward movement direction. 
     
     
         9 . A machine for wrapping a product in a film, the machine comprising:
 at least first and second spaced-apart transverse counter-jaws that form a part of a transporter that is configured to move the product in a forward movement direction, a space being provided between the first and second spaced-apart transverse counter-jaws sufficient to house the product,   at least first and second spaced-apart transverse jaws. each of the first and second transverse jaws moveable independently with respect to the first and second transverse counter-jaws, respectively, between an open position wherein the first and second transverse jaws are spaced apart from the respective first and second transverse counter-jaws and a closed position wherein the first and second transverse jaws interact with the respective first and second transverse counter-jaws,   a lower unwinder for a first reel of film that is configured to cause the film from the first reel to be arranged on the first and second transverse counter-jaws and below a lower portion of the product,   an upper unwinder for a second reel of film that is configured to cause the film from the second reel to be arranged on an upper portion of the product;   the transporter configured to move the product with the first and second transverse counter-jaws in a forward movement direction during the process of applying the film to the product,   a first actuator that is configured to move the first and second spaced-apart transverse jaws together in the forward movement direction and to maintain the first and second transverse jaws respectively in alignment with the first and second transverse counter-jaws as the transporter moves the product in the forward movement direction,   a second actuator configured to independently act on the first transverse jaw to move the first transverse jaw between the open and closed positions,   a third actuator configured to independently act on the second transverse jaw to move the second transverse jaw between the open and closed positions;   a tensioner configured to apply a tension to the film supplied by the second reel in a direction having a directional component opposite the forward movement direction; and   a controller configured to (i) act on the second actuator to cause the first transverse jaw to move from the open position to the closed position to join and then cut the joined films received from the first and second reels adjacent a first side of the product and to act on the third actuator to cause the second transverse jaw to assume or maintain the open position, (ii) subsequent to the cutting of the joined films in step (i), act on the second actuator to cause the first transverse jaw to assume the open position to permit the tensioner to apply tension to the film received from the second reel to collect a part of the film received from the second reel, and (iii) subsequent to the tension being supplied to the film received from the second reel, act on the third actuator to cause the second transverse jaw to move from the open position to a closed position to join and then cut the joined films adjacent a second side of the product.   
     
     
         10 . A machine according to  claim 9 , comprising separating means for peeling the film off the second transverse counter-jaw once the second transverse jaw has stopped interacting with the second transverse counter-jaw, the separating means configured to cause the distance between the product and the second transverse counter-jaw to increase. 
     
     
         11 . A machine according to  claim 10 , wherein to increase the distance between the product and the second transverse counter-jaw, the separating means is configured to cause the transporter to become misaligned along a length thereof that houses the product already wrapped. 
     
     
         12 . A machine according to  claim 11 , wherein the separating means comprises a forward roller, an intermediate roller and a rear roller distributed in the forward movement direction, the forward roller and the rear roller being longitudinally aligned with one another and the intermediate roller being arranged such that it is misaligned with respect to the longitudinal alignment of the forward and rear rollers. 
     
     
         13 . A machine according to  claim 12 , wherein the intermediate roller is arranged at a height less than the height at which the forward and rear rollers are arranged, the transporter configured to pass under the forward roller and the rear roller and over the intermediate roller. 
     
     
         14 . A machine according to  claim 13 , wherein the intermediate roller is sized such that the first and second transverse counter-jaws are inclined in opposite directions when they are located on the intermediate roller, following a curved path with respect to an axis of rotation of the intermediate roller. 
     
     
         15 . A machine according to  claim 10 , comprising a fourth actuator configured to act on the lower portion of the product to separate it from the second transverse counter-jaw. 
     
     
         16 . A machine according to  claim 9 , wherein the tensioner is associated with the upper unwinder and is suitable for acting on the film from the second reel arranged in said upper unwinder. 
     
     
         17 . A method for wrapping first and second products in a film by use of a machine comprising at least first, second and third spaced-apart transverse counter-jaws and at least first, second and third spaced-apart transverse jaws, each of the first, second and third transverse jaws moveable independently with respect to the first, second and third transverse counter-jaws, respectively, between an open position wherein the first, second and third transverse jaws are spaced apart from the respective first, second and third transverse counter-jaws and a closed position wherein the first, second and third transverse jaws interact with the respective first, second and third transverse counter-jaws, the method comprising:
 arranging a first film on or adjacent the first, second and third transverse counter-jaws,   positioning the first product in a space between the first and second transverse counter-jaws so that a lower portion of the first product is in contact with the first film,   positioning the second product in a space between the second and third transverse counter-jaws so that a lower portion of the second product is in contact with the first film,   moving the first and second products with the first, second and third transverse counter-jaws in a forward movement direction during which a second film is arranged on an upper portion of the first and second products, each of the first, second and third transverse jaws being moved together in the forward movement direction so as to be aligned with the first, second and third transverse counter-jaws, respectively,   moving the first transverse jaw from the open position to a closed position to join and then cut the joined first and second films adjacent a first side of the product while maintaining the second and third transverse jaws in the open position,   moving the first transverse jaw from the closed position to the open position,   while the first, second and third transverse jaws are open, applying a tension to the second film in a direction having a directional component opposite the forward movement direction to collect a part of the second film,   subsequent to applying the tension to the second film, moving the second transverse jaw from the open position to a closed position to join and then cut the joined first and second films adjacent a second side of the first product and a first side of the second product while maintaining the first and third transverse jaws in the open position,   moving the second transverse jaw from the closed position to the open position; and   while the second and third transverse jaws are open, applying a tension to the second film in a direction having a directional component opposite the forward movement direction to collect a part of the second film.   
     
     
         18 . A method according to  claim 17 , wherein sufficient tension is applied to the second film to remove the wrapped film from the first and second transverse counter-jaws. 
     
     
         19 . A method according to  claim 17 , wherein the step of moving the first transverse jaw from the open position to the closed position to join and then cut the joined first and second films adjacent a first side of the product results in a first space being formed between at least a portion of the joined first and second films and the first side of the first product, and wherein the step of moving the second transverse jaw from the open position to the closed position to join and then cut the joined first and second films adjacent a first side of the second product results in a second space being formed between at least a portion of the joined first and second films and the first side of the second product, the tension being applied to the second film in a manner sufficient to reduce or remove the first and second spaces.