Packaging Machine For Vacuum Skin Packaging

Abstract

A vacuum-skin packaging machine for sealing film onto a tray containing a product includes a vacuum system. The vacuum system includes a vacuum pump, piping, and valves. The machine includes a top structure and a bottom structure defining a vacuum chamber in communication with the vacuum pump via the piping. An actuating mechanism transitions the top structure and the bottom structure between an opened state where they are separated and a closed state where they are sealed. A platen-movement mechanism moves a platen to the chamber while the top and bottom structures are in the opened state. The platen holds the trays. A heating plate heats the film while the top and bottom structures are in the closed position. The heated film is forced against the trays in response to a valve venting a region of the vacuum chamber adjacent to the heated film.

What is claimed is: 
     
         1 . A method for providing a vacuum-skin packaging for products on trays using a vacuum chamber defined by a top structure and a bottom structure, comprising:
 while the bottom structure is retracted away from the top structure, automatically moving a platen along a path that extends into the vacuum chamber, the platen holding one or more of the trays;   positioning a film over the platen;   after the platen is positioned within the vacuum chamber, moving the bottom structure upwardly against the top structure so as to form a seal between the top structure and the bottom structure;   creating a vacuum within the vacuum chamber, the film dividing the vacuum chamber into an upper volume and a lower volume;   heating the film;   venting the upper volume above the platen to force the heated film onto the platen and the one or more trays;   retracting the bottom structure from the top structure of the vacuum chamber; and   after the retracting, automatically moving the platen along the path out of the vacuum chamber.   
     
     
         2 . The method of  claim 1 , wherein the automatic moving of the platen along the path into or out of the vacuum chamber is in response to activating at least one of a power-driven roller or a power-driven slide element. 
     
     
         3 . The method of  claim 1 , wherein the automatic moving of the platen along the path out of the vacuum chamber is in response to a second platen engaging the platen as the second platen enters the vacuum chamber. 
     
     
         4 . The method of  claim 1 , wherein the heating the film occurs by use of a heating plate located within the upper structure adjacent to the film. 
     
     
         5 . The method of  claim 1 , wherein the positioning the film occurs though an automated film-feeding mechanism that pulls the film from a web into the vacuum chamber in a direction that is generally parallel to the path of the platen. 
     
     
         6 . The method of  claim 1 , wherein the platen holds a plurality of the trays, and the method further includes cutting the film in multiple directions with a plurality of knives to create individual packaged trays that can be independently removed from the platen. 
     
     
         7 . The method of  claim 1 , wherein the platen is held within the vacuum chamber via a stationary platform located within the bottom structure, the stationary platform being supported by at least one elongated support member, the bottom structure includes at least one opening for receiving the at least one elongated support member. 
     
     
         8 . The method of  claim 7 , wherein the at least one elongated support member includes an internal air conduit that is used to for creating the vacuum within the low volume. 
     
     
         9 . The method of  claim 1 , further including, after the trays have been removed from the platen after exiting the vacuum chamber, transferring the platen along a path that returns the platen to an entry point where non-filmed trays can be loaded on the platen and the platen can re-enter vacuum chamber. 
     
     
         10 . The method of  claim 1 , further including venting the lower volume after the venting of the upper volume. 
     
     
         11 . A vacuum-skin packaging machine for sealing film onto a tray containing a product, comprising:
 a vacuum system including a vacuum pump, piping, and valves;   a top structure and a bottom structure defining a chamber, the chamber being in communication with the vacuum pump via the piping;   an actuating mechanism to transition the top structure and the bottom structure between (i) an opened state whereby the top structure and the bottom structure are separated and (ii) a closed state whereby the top structure and the bottom structure are sealed together; and   a first platen-movement mechanism to automatically move a platen from an in-feed position to within the chamber while the top structure and bottom structure are in the opened state, the platen holding the tray; and   a heating plate to heat the film while the top structure and bottom structure are in the closed position, the heated film being forced against the platen and the tray in response to one or more of the valves venting a region of the chamber adjacent to the heated film.   
     
     
         12 . The vacuum-skin packaging machine of  claim 11 , further including a second platen-moving mechanism to automatically move the platen from the chamber after receiving the heated film. 
     
     
         13 . The vacuum-skin packaging machine of  claim 11 , further including an automatic film-feeding mechanism to move the film into the chamber when the top structure and the bottom structure are in the opened state. 
     
     
         14 . The vacuum-skin packaging machine of  claim 13 , further including an automatic film-cutting mechanism outside the chamber to cut the film after the top structure and the bottom structure are in the closed state. 
     
     
         15 . The vacuum-skin packaging machine of  claim 11 , further including a cutting station along the path outside the chamber, the cutting station automatically cutting the film that is attached to the trays on the platen in multiple directions with a plurality of knives. 
     
     
         16 . The vacuum-skin packaging machine of  claim 11 , further including platen-support structures to define a continuous platen-movement path on which the platens move from a loading station where trays are loaded on the platen, then to the chamber where the film is sealed against the trays, then to a removal station where the filmed trays are removed from the platens, and then back to the loading station. 
     
     
         17 . The vacuum-skin packaging machine of  claim 16 , further including platen-moving mechanisms that automatically move the platens around the continuous platen-movement path. 
     
     
         18 . A vacuum-skin packaging machine for sealing film onto a tray containing a product, comprising:
 a vacuum system including a vacuum pump, piping, and valves;   a top structure and a bottom structure defining a chamber, the top structure and the bottom structure being transitionable between (i) an opened position whereby the top structure and the bottom structure are separated and platens can enter and exit the chamber and (ii) a closed position whereby the top structure and the bottom structure are sealed together to create a vacuum chamber in which heat is applied to the film to attach the film to the trays on the platens; and   a continuous platen-movement path on which the platens move from a loading station where trays are loaded on the platen, into the vacuum chamber where the film is sealed against the trays, to a removal station where the filmed trays are removed from the platens, and back to the loading station.   
     
     
         19 . The vacuum-skin packaging machine of  claim 18 , wherein the continuous platen-movement path further includes one or more cutting station located after the vacuum chamber and before the removal station, the cutting station automatically cutting the film in multiple directions with a plurality of knives. 
     
     
         20 . The vacuum-skin packaging machine of  claim 18 , further including a vacuum system including a vacuum pump, a first set of piping, and a second set of piping, the first set of piping being in communication with an upper volume located above the film within the vacuum chamber, the second set of piping being in communication with a lower volume located below the film within the vacuum chamber