Film side sealing apparatus with closed-loop temperature control of a heater

Abstract

A side sealing apparatus for a shrink packaging machine comprising closed loop temperature control of a heater for maintaining an optimum temperature for cutting and sealing two layers of thermoplastic film. The heater comprises a cable or cartridge heater with an internal thermocouple, and it is connected to an automatic temperature controller. The heater is mounted on the side sealer apparatus between two sets of top and bottom V-belts mounted around drive rolls and idler rolls. The V-belts provide nip pressure against the film in order to drive the film. In one embodiment, nip pressure is generated by nip rollers on the scrap side of the film, and by low friction belt support guides on the package side of the film. In another embodiment, the belt support guides are replaced with a series of upper and lower nip rollers, and adjustable toggle clamps provide adjustable pressure on the series of upper and lower nip rollers.

1 . A side sealer apparatus for cutting and sealing two layers of film together near an edge of heat-sealable material comprising: 
 means for moving the heat-sealable material through the side sealer apparatus;    means attached to said side sealer apparatus in the path of said heat-sealable material for generating heat to cut and seal said heat-sealable material near said edge;    a top drive roll spaced-apart from a top idler roll;    a bottom drive roll spaced-apart from a bottom idler roll and positioned immediately under the top drive roll and top idler roll respectively;    a first pair of spaced-apart V-belts positioned around and between the top drive roll and the top idler roll on a side of the apparatus above the moving means;    a second pair of spaced-apart V-belts positioned around and between the bottom driver roll and the bottom idler roll;    a top belt guide, having a low coefficient of friction and a bottom groove for a lower portion of an outer one of the first pair of spaced apart V-belts to travel in, to provide nip pressure on the heat-sealable material; and    a bottom belt guide, having a low coefficient of friction and a top groove for an upper portion of an outer one of the second pair of spaced apart V-belts to travel in, to provide nip pressure on the heat-sealable material.    
     
     
         2 . The side sealer apparatus as recited in  claim 1  wherein: 
 said heat generating means is mounted on said side sealer apparatus at a predetermined angle relative to horizontal between the V-belts positioned on an inner side of the heater and the V-belts positioned on an outer side of the heater.    
     
     
         3 . The side sealer apparatus as recited in  claim 1  wherein said heat-sealable material comprises a thermoplastic film.  
     
     
         4 . The side sealer apparatus as recited in  claim 1  wherein said heat generating means comprises an elongated metal sheathed body including an internal heating mechanism and a thermocouple.  
     
     
         5 . The side sealer apparatus as recited in  claim 1  wherein said moving means comprises a conveyor.  
     
     
         6 . The side sealer apparatus as recited in  claim 1 , wherein said apparatus comprises means connected to said heat generating means for providing closed loop control of said heat generating means in accordance with a predetermined heat setting.  
     
     
         7 . A side sealer apparatus for cutting and sealing two layers of heat-sealable film together near an edge comprising: 
 means for moving the heat-sealable material through said side sealer apparatus;    means attached to said side sealer apparatus in the path of said heat-sealable film for generating heat to cut and seal said heat-sealable film together near said edges;    a top drive roll spaced-apart from a top idler roll;    a bottom drive roll spaced-apart from a bottom idler roll and positioned immediately under said top drive roll and said top idler roll respectively;    a first pair of spaced-apart V-belts positioned around and between said top drive roll and said top idler roll on a side of the apparatus above the moving means;    a second pair of spaced-apart V-belts positioned around and between said bottom driver roll and said bottom idler roll;    a plurality of pairs of upper nip rollers positioned between said top drive roll and said top idler roll and in contact with a lower portion of said first pair of spaced-apart V-belts;    a plurality of pairs of lower nip rollers positioned between said bottom drive roll and said bottom idler roll and in contact with an upper portion of said second pair of spaced-apart V-belts; and    means for providing an adjustable nip pressure on said pairs of upper nip rollers in contact with said first pair of spaced-apart V-belts.    
     
     
         8 . The side sealer apparatus as recited in  claim 7  wherein said moving means comprises a conveyor.  
     
     
         9 . The side sealer apparatus as recited in  claim 7  wherein said heat generating means comprises an elongated metal sheathed body including an internal heating mechanism and a thermocouple.  
     
     
         10 . The side sealer apparatus as recited in  claim 7  wherein said heat-sealable film comprises a thermoplastic film.  
     
     
         11 . The side sealer apparatus as recited in  claim 7  wherein: 
 said heat generating means is mounted on said side sealer apparatus at a predetermined angle relative to horizontal between one of said V-belts positioned on an inner side of the heater and one of said V-belts positioned on an outer side of the heater.    
     
     
         12 . The side sealer apparatus as recited in  claim 7 , wherein said apparatus comprises means connected to said heat generating means for providing closed loop control of said heat generating means in accordance with a predetermined heat setting.  
     
     
         13 . The side sealer apparatus as recited in  claim 7  wherein said means for providing an adjustable nip pressure on said pairs of upper nip rollers in contact with said first pair of spaced-apart V-belts comprises: 
 a nip roller mounting frame for holding said upper nip rollers in a horizontal row, said nip roller mounting frame being attached to a wall of said side sealer via a hinge; and    means for applying pressure to an upper surface of said nip roller mounting frame to produce said adjustable nip pressure.    
     
     
         14 . The side sealer as recited in  claim 13 , wherein said pressure applying means comprises at least one toggle clamp having a leg extending to and in contact with said upper surface of said nip roller mounting frame.  
     
     
         15 . A side sealer apparatus for cutting and sealing of heat-sealable film together near an edge comprising: 
 means attached to said side sealer apparatus in a path of said heat-sealable film for generating heat to cut and seal said heat-sealable film together near an edge;    a top drive roll spaced-apart from a top idler roll;    a bottom drive roll spaced-apart from a bottom idler roll and positioned immediately under said top drive roll and said top idler roll respectively;    a first pair of spaced-apart V-belts positioned around and between said top drive roll and said top idler roll on a side of the apparatus above the moving means;    a second pair of spaced-apart V-belts positioned around and between said bottom driver roll and said bottom idler roll;    a plurality of pairs of upper nip rollers positioned between said top drive roll and said top idler roll and in contact with a lower portion of said first pair of spaced-apart V-belts;    a plurality of pairs of lower nip rollers positioned between said bottom drive roll and said bottom idler roll and in contact with an upper portion of said second pair of spaced-apart V-belts; and    means for providing an adjustable nip pressure on said pairs of upper nip rollers in contact with said first pair of spaced-apart V-belts.    
     
     
         16 . The side sealer apparatus as recited in  claim 15 , wherein said heat generating means comprises an elongated metal sheathed body including an internal heating mechanism and a thermocouple.  
     
     
         17 . The side sealer apparatus as recited in  claim 15 , wherein said heat-sealable film comprises a thermoplastic film.  
     
     
         18 . The side sealer apparatus as recited in  claim 15  wherein: 
 said heat generating means is mounted on said side sealer apparatus at a predetermined angle relative to horizontal between one of said V-belts positioned on an inner side of the heater and one of said V-belts positioned on an outer side of the heater.    
     
     
         19 . The side sealer apparatus as recited in  claim 15 , wherein said apparatus comprises means connected to said heat generating means for providing closed loop control of said heat generating means in accordance with a predetermined heat setting.  
     
     
         20 . The side sealer apparatus as recited in  claim 15 , wherein said means for providing an adjustable nip pressure on said pairs of upper nip rollers in contact with said first pair of spaced-apart V-belts comprises: 
 a nip roller mounting frame for holding said upper nip rollers in a horizontal row, said nip roller mounting frame being attached to a wall of said side sealer via a hinge; and    means for applying pressure to an upper surface of said nip roller mounting frame.    
     
     
         21 . The side sealer as recited in  claim 20 , wherein said pressure applying means comprises at least one toggle clamp having a leg extending to and in contact with said upper surface of said nip roller mounting frame.  
     
     
         22 . A method for cutting and sealing two layers of heat-sealable film together near an edge in a side sealer apparatus comprising the steps of: 
 moving said heat-sealable film through said side sealer apparatus;    generating heat to cut and seal said heat-sealable film together near said edge with means attached to said side sealer apparatus in the path of said film;    providing a top drive roll spaced-apart from a top idler roll on said side sealer apparatus;    providing a bottom drive roll spaced-apart from a bottom idler roll on said side sealer and positioned immediately under said top drive roll and said top idler roll respectively;    positioning a first pair of spaced-apart V-belts around and between said top drive roll and said top idler roll on a side of said side sealer apparatus above said means for moving said film;    positioning a second pair of spaced-apart V-belts around and between said bottom driver roll and said bottom idler roll;    attaching a plurality of pairs of upper nip rollers between said top drive roll and said top idler roll and in contact with a lower portion of said first pair of spaced-apart V-belts;    attaching a plurality of pairs of lower nip rollers between said bottom drive roll and said bottom idler roll and in contact with an upper portion of said second pair of spaced-apart V-belts; and    providing an adjustable nip pressure on said pairs of upper nip rollers in contact with said first pair of spaced-apart V-belts.    
     
     
         23 . The method as recited in  claim 22  wherein said step of moving said heat-sealable film through said side sealer apparatus comprises the step of providing a conveyor.  
     
     
         24 . The method as recited in  claim 22  wherein said step of generating heat comprises the step of providing an elongated metal sheathed body including an internal heating mechanism and a thermocouple.  
     
     
         25 . The method as recited in  claim 22  wherein said method comprises the step of sealing thermoplastic film.  
     
     
         26 . The method as recited in  claim 22  wherein said step of generating heat comprises the step of mounting a heat generating means on said side sealer apparatus at a predetermined angle relative to horizontal between one of said V-belts positioned on an inner side of the heater and one of said V-belts positioned on an outer side of the heater.  
     
     
         27 . The method as recited in  claim 22  wherein said step of generating heat to cut and seal said heat-sealable film comprises the step of providing closed loop control of means for generating said heat in accordance with a predetermined heat setting heat setting.  
     
     
         28 . The method as recited in  claim 22  wherein said step of providing an adjustable nip pressure on said pairs of upper nip rollers in contact with said first pair of spaced-apart V-belts comprises the steps of: 
 holding said upper nip rollers in a horizontal row with a nip roller mounting frame, said nip roller mounting frame being attached to a wall of said side sealer via a hinge; and    applying pressure to an upper surface of said nip roller mounting frame to move said mounting frame downward and provide said adjustable nip pressure.    
     
     
         29 . The method as recited in  claim 28 , wherein said step of applying pressure comprises the step of providing at least one toggle clamp having a leg extending to and in contact with said upper surface of said nip roller mounting frame.