Top formed packaging

Abstract

A packaging machine may package irregularly shaped food products such that a heat-sensitive lidding material is thermoformed to generally conform to the configuration of the food product.

What is claimed is:  
     
         1 . A method of generating a package containing a food product, the package including a preformed tray defining a peripheral flange and a thermoformable flexible lidding material, the method comprising the steps of: 
 mounting a female thermoforming mold within the perimeter of a heat-sealing platen allowing an insulated area between the female thermoforming mold and the heat-sealing platen sufficient to cause a differential in temperature between the heat-sealing platen and the female thermoforming mold;    thermoforming a flexible lidding into the general configuration of said female thermoforming mold; and    ventilation to atmosphere through said thermoforming mold so that the thermoformable flexible lidding material generally conforms to the configuration of the food product contained within a preformed tray.    
     
     
         2 . The method as defined in  claim 1  wherein the female thermoforming mold is mounted within the perimeter of a heat-sealing platen so as to allow for a void area between the female thermoforming mold and the heat-sealing platen.  
     
     
         3 . The method as defined in  claim 1  wherein the ventilation to atmosphere is replaced with ventilation via compressed air.  
     
     
         4 . A method of manufacturing a packaging device comprising: 
 providing a heat-sealing platen, said platen having an exterior wall, an interior wall and a base;    disposing a thermoforming mold within the boundary defined by the interior wall of said platen; and    spacing said mold apart from said platen.    
     
     
         5 . The method of  claim 4  wherein providing a heat-sealing platen includes providing at least one aperture in said base.  
     
     
         6 . The method of  claim 4  wherein disposing a thermoforming mold within the boundary defined by the interior wall includes disposing a female thermoforming mold having a plurality of apertures.  
     
     
         7 . The method of  claim 4  further including providing an insulative spacer to space said mold apart from said platen.  
     
     
         8 . The method of  claim 7  further including bolting said thermoforming mold to said platen such that a bolt secures said spacer between said mold and said platen.  
     
     
         9 . The method of  claim 4  further including housing said heat-sealing platen and said thermoforming mold within a vacuum chamber.  
     
     
         10 . The method of  claim 9  further including providing a vacuum source, a source for producing a positive pressure modified atmosphere and a vent to the ambient atmosphere to said vacuum chamber.  
     
     
         11 . A packaging apparatus comprising: 
 a vacuum chamber;    a first heated member disposed within said vacuum chamber; and    a vacuum source coupled to said vacuum chamber.    
     
     
         12 . The apparatus of  claim 11  further including a second heated member coupled to said first heated member.  
     
     
         13 . The apparatus of  claim 12  further including a heat resistant spacer disposed between said first and second heated members.  
     
     
         14 . The apparatus of  claim 13  wherein said first heated member is a female thermoforming mold.  
     
     
         15 . The apparatus of  claim 14  wherein said second heated member is a platen.  
     
     
         16 . The apparatus of  claim 15  further including a bolt to couple said mold to said platen and to secure said spacer there between.  
     
     
         17 . The apparatus of  claim 11  further including a source to provide a positive pressure modified atmosphere coupled to said vacuum chamber.  
     
     
         18 . The apparatus if  claim 17  further including a vent to the ambient atmosphere coupled to said chamber.  
     
     
         19 . An apparatus for packaging food products comprising: 
 an upper housing defining a first chamber;    a lower housing defining a second chamber, said lower housing opposite said upper housing;    a heat-sealing platen disposed within said upper chamber;    a thermoforming mold coupled to said platen;    a spacer disposed between said mold and said platen;    a vacuum source in communication with said upper and lower chambers;    a source for positive pressure modified atmosphere in communication with said lower chamber; and    a vent to ambient atmosphere in communication with said upper chamber.    
     
     
         20 . The apparatus of  claim 19  further including at least one bolt to attach said mold to said platen and to secure said spacer between said mold and said platen.  
     
     
         21 . The apparatus of  claim 19  further including a severing device housed within said upper chamber.  
     
     
         22 . The apparatus of  claim 19  further including a tray carrier to transport said food package to said upper and lower housings.  
     
     
         23 . The apparatus of  claim 19  wherein said platen includes an interior wall, an exterior wall and a base.  
     
     
         24 . The apparatus of  claim 23  further including disposing said mold within the boundary defined by the interior wall of said platen.  
     
     
         25 . The apparatus of  claim 19  wherein said platen includes at least one aperture.  
     
     
         26 . The apparatus of  claim 19  wherein said platen is spaced apart from said upper housing.  
     
     
         27 . A method of packaging a food product comprising: 
 using a tray carrier, positioning a preformed tray containing a food product within a vacuum chamber, said vacuum chamber including a heat-sealing platen with a female thermoforming mold coupled to said platen;    positioning a sheet of lidding material over said tray;    thermoforming said lidding material into the general configuration of the female thermoforming mold; and    ventilating to atmosphere such that said lidding material generally conforms to the configuration of the food product contained within said tray.    
     
     
         28 . The method of  claim 27  wherein thermoforming said lidding material includes creating a pressure differential across said lidding material to cause that portion of the lidding material over the food product to lift in the direction of said mold.  
     
     
         29 . The method of  claim 28  further including evacuating ambient atmosphere from said tray.  
     
     
         30 . The method of  claim 29  further including introducing a positive pressure modified atmosphere gas into said chamber to force the lidding material into direct contact with the mold.  
     
     
         31 . The method of  claim 30  further including heating said platen to hermetically heat-seal said lidding material to said tray.  
     
     
         32 . The method of  claim 31  further including heating said mold.  
     
     
         33 . The method of  claim 32  further including creating a temperature differential between said heat-sealing platen and said mold.  
     
     
         34 . The method of  claim 33  further including driving said platen into contact with said lidding material to heat-seal said lidding material to the periphery of said tray.  
     
     
         35 . The method of  claim 27  further including severing the excess lidding material from the perimeter of the tray.  
     
     
         36 . A package for food products comprising: 
 a tray; and    a flexible lidding material that is stretched, heated and lifted away from a food product situated within said tray.    
     
     
         37 . The package of  claim 36  wherein said lidding material is cooled and conformed to the surface of said food product.  
     
     
         38 . The package of  claim 37  wherein said lidding material is heat-sealed to a flange on said tray.  
     
     
         39 . A method of packaging comprising: 
 in a sealed chamber, positioning a sheet of flexible lidding material over a tray containing a food product;    causing said lidding material to come into contact with a female thermoforming mold situated within said chamber; and    forcing said lidding material into conformity with the food product.    
     
     
         40 . The method of  claim 39  further including heating said lidding material.  
     
     
         41 . The method of  claim 39  wherein causing said lidding material to come into contact with a female thermoforming mold includes creating a pressure differential across said lidding material to cause said lidding material to lift in the direction of said mold.  
     
     
         42 . The method of  claim 41  wherein causing said lidding material to come into contact with a female thermoforming mold includes introducing a positive pressure gas into the sealed chamber.  
     
     
         43 . The method of  claim 42  wherein introducing a positive pressure gas into the sealed chamber includes introducing a positive pressure modified atmospheric gas into said chamber.  
     
     
         44 . The method of  claim 39  further including evacuating the ambient atmosphere from said tray.  
     
     
         45 . The method of  claim 39  further including heat-sealing said lidding material to said tray.  
     
     
         46 . The method of  claim 45  further including removing excess lidding from the outside perimeter of said tray.  
     
     
         47 . A method of packaging comprising: 
 lifting a flexible lidding material away from a food product disposed within a preformed tray; and    conforming said lidding material to the surface contours of said food product.    
     
     
         48 . The method of  claim 47  further including heating said lidding material as it is lifted away from said food product.  
     
     
         49 . The method of  claim 48  further including stretching said lidding material.  
     
     
         50 . The method of  claim 49  further including cooling and shrinking said lidding material to permanently conform it to the surface contours of said food product.  
     
     
         51 . The method of  claim 47  further including causing said lidding material to come in contact with a heated female thermoforming mold.  
     
     
         52 . The method of  claim 47  further including heat-sealing said material to said tray.  
     
     
         53 . The method of  claim 52  further including removing excess lidding material from the perimeter of said tray.  
     
     
         54 . The method of  claim 47  wherein lifting said lidding material includes creating a pressure differential across said lidding material.  
     
     
         55 . The method of  claim 54  wherein lifting said lidding material includes introducing a positive pressure modified atmospheric gas into the confines of said tray.  
     
     
         56 . The method of  claim 55  further including evacuating ambient atmosphere from said tray.  
     
     
         57 . The method of  claim 47  wherein conforming said lidding material to the surface contours of said food product includes introducing ambient pressure external to said lidding.