Abstract:
An apparatus and method for vacuum sealing a food item package. Compressed air forces air out of a food item package such that there is substantially no air within the package after it is sealed.

Description:
REFERENCE TO PENDING APPLICATIONS 
   This patent application claims priority to and is a continuation of U.S. patent Ser. No. 11/255,786 now U.S. Pat. No. 7,516,594, filed Oct. 21, 2005, which is a continuation of U.S. patent application Ser. No. 10/765,364, filed Jan. 27, 2004 now abandoned; which is a continuation-in part of U.S. patent application Ser. No. 09/932,315, filed on Aug. 17, 2001 now U.S. Pat. No. 6,691,491, which claims priority to U.S. Provisional Application No. 60/226,627 filed on Aug. 18, 2000. 

   REFERENCE TO MICROFICHE APPENDIX 
   This application is not referenced in any microfiche appendix. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an improved vertical form, fill and seal packaging machine. More specifically, the present invention relates to a vertical food packaging machine that forms a vacuum seal of the packaged food products. 
   2. Prior Art 
   It is often desirable to seal packaged food products under a vacuum. This is typically accomplished by sucking the air out of a package prior to it being sealed. Those skilled in the art will appreciate that this is generally time consuming and therefore slows packaging process significantly. 
   It is therefore desirable to provide a method for rapid, sterile vacuum sealing of packaged food items. 
   The present invention relates to apparati and methods for making air tight bags or packages for use with a multiple purpose convertible vertical form, fill and seal machine and method for making a variety of styles or types of bags including overlap or fin seals, pillow, potato chip, non-reclosable or reclosable, product-filled bags and especially zipper lock reclosable bags. 
   Package or bag making machines generally referred to as vertical form, fill and seal machines and methods for manufacturing individual pillow type packages with non-reclosable, midline overlap longitudinal seams or seals are described, for example, U.S. Pat. No. 4,532,753 to Kovacs, granted Aug. 6, 1985 (U.S. Cl. 53/451); U.S. Pat. No. 4,768,327 to Mosher, granted Sep. 6, 1988 (U.S. Cl. 53/451); U.S. Pat. No. 4,965,986 to Klinkel, granted Oct. 30, 1990 (U.S. Cl. 53/551); U.S. Pat. No. 4,999,974 to Kovacs, et al., granted Mar. 19, 1991 (U.S. Cl. 53/434); and U.S. Pat. No. 5,279,098 to Fukuda, granted Jan. 18, 1994 (U.S. Cl. 53/451). Typically, a heat sealable web material is supplied from a roll and is guided to a former located at the upper end of the machine. The former folds the flat web material into a vertically oriented tube surrounding a tubular filling mandrel or pipe. The edges of the folded web material overlap one another, and, as the folded tube moves downwardly over the mandrel, the overlapped marginal edge portions are heat sealed to one another by a cyclicly operated longitudinal sealing mechanism. The web is thus formed into a web tube which is advanced through the machine in package length 
   Attempts have been made to provide a vertical form; fill and seal machine which produces more than one type of package. 
   Various zippered and zipper lock packages are seen in the following patents: U.S. Pat. No. 6,059,456, “Reclosable Profile Arrangement Using Slidable Closure Strip”, U.S. Pat. No. 5,924,173, “End Posts For Plastic Zipper”, U.S. Pat. No. 5,896,627, “High-strength Slide R For a Reclosable Bag”, U.S. Pat. No. 5,833,791, “Conforming End Stops For a Plastic Zipper”, U.S. Pat. No. 5,775,812, “Tamper-Evident Reclosable Plastic Bag With Breakaway Slide R”, U.S. Pat. No. 5,713,669, “Plastic Bag With Zipper Slide R Captured in Pocket”, and U.S. Pat. No. 5,669,715, “Tamper-Evident Reclosable Plastic Bag With Slide R”, the teachings of which are expressly incorporated by reference herein. 
   SUMMARY OF THE INVENTION 
   In accordance with an exemplary embodiment of the present invention, a convertible, highly adaptable, versatile vertical form, fill and seal machine and method is provided which not only makes edge fin seal non-reclosable or reclosable bags, but also is easily converted to produce other styles and types of durable, substantially air tight, product-filled and vacuum sealed bags at high speed and provides for the production of different size bags and accommodates different types and amounts of product in the bags. 
   In accordance with another exemplary embodiment of the present invention, a vertical form, fill and seal machine and method is provided which makes edge fin seal non-reclosable or reclosable product-filled and vacuum sealed bags. In accordance with yet another exemplary embodiment of the present invention, a vertical form, fill and seal machine and method is provided which makes midline overlap or fin seal pillow style non-reclosable or reclosable product-filled bags. 
   The present invention utilizes compressed air to vacuum seal a package containing food items. The device utilizes a clam-shell design to surround packaged food items and compress the packaging using compressed air. The device is easily retrofitted to packaging machinery such as that described in the above mentioned patents. Many packaging machines are pneumatically driven and so the present invention is easily incorporated into existing machines. 
   A vacuum supply is provided to hold open a small hole in the packaging so that air is allowed to escape. This is an important feature of the invention. Without a means of holding the package open, air within the package would not be allowed to escape. Once air has been removed from the package, the package may be heat sealed and separated from the web by any of a variety of methods known in the art. The use of compressed air allows a package to be vacuum sealed rapidly and slows the packaging process only slightly. 
   It is therefore an object of the present invention to provide a method for rapidly heat sealing a food item package in a sterile manner. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a cross-section view of the present invention. 
       FIG. 2  shows a perspective view of the present invention. 
       FIG. 3  shows a top view of the present invention. 
       FIG. 4  shows an alternative embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The embodiments discussed herein are merely illustrative of specific, manners in which to make and use the invention and are not to be interpreted as limiting the scope of the instant invention. 
   While the invention has been described with a certain degree of particularity, it is to be noted that many modifications may be made in the details of the invention&#39;s construction and the arrangement of its components without departing from the spirit and scope of this disclosure. It is understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification. 
   The present invention is preferably incorporated into the bottom of a vertical form, fill and seal packaging machine. It is located directly below the sealing mechanism. The clam shell design has two sides that come together to surround the lower most portion of a web having food items placed within it. Vacuum suction is applied to the web in order to maintain a hole between the portion of the web being formed into a food item package and the remaining part of the web such that they are in fluid communication. This ensures that the air within the portion of the web to be packaged has a route for leaving the packaging. The two halves of the invention come together, surrounding the portion of the web to be packaged and form an air tight seal. Compressed air is then applied to the chamber formed by the two halves of the invention. This forces air out of the food item package and into the remainder of the web. The packaged portion of the web is then heat sealed. The two halves of the invention then are drawn apart and the package is allowed to fall. This process is then repeated with the next portion of the web to be formed into a package. 
     FIG. 1  shows the present invention  10 . Web  54  includes packaging portion  40  that is filled with food items  42 . Clam shells  56  and  58  are held together such that they form air tight chamber  44 . Clam shell  56  is comprised of top wall  20 , bottom wall  16  and rear wall  14 . The side walls are not shown in  FIG. 1 . Similarly, clam shell  58  comprises top wall  22 , bottom wall  18 , and rear wall  12 . Clam shells  56  and  58  are preferably comprised of stainless steel but may be comprised of other materials known in the art. As can be seen, top walls  20  and  22  include lips  50  and  52  respectively. These lips form a small opening through which air may pass from package portion  40  to the remainder of the web  54 . Once clam shells  56  and  58  are engaged with each other to form chamber  44 , a vacuum is applied to lips  50  and  52  by means of tubes  36  and  38  and through passages  24  and  26 . This holds the web open and prevents compressed air in chamber  44  from leaking between lips  50  and  52  and closing off the opening between package portion  40  and the web  54 . 
   Compressed air is then applied to chamber  44  by tube  48  through hole  46 . The compressed air in chamber  44  forces air out of package portion  40  and into web  54 . Heat sealing mechanisms  28  and  30  are then moved in the direction of arrow  34  and arrow  32  respectively. Devices  28  and  30  then melt the web and detach package portion  40  from web  54 . Clam shell  56  is then moved in the direction of arrow  60  while clam shell  58  is simultaneously moved in the direction of arrow  62 . This allows the package to drop below the device. Typically it will drop onto a conveyor belt. 
     FIG. 2  shows a perspective view of the present invention. Here, side walls  66 ,  72  and  68  can be seen. When the two sides of the device engage one another, surface  70  creates an air tight seal. Surface  70  preferably has a rubber or similar coating in order to ensure that the seal is air tight. In this view, tube  48  is attached to side wall  68  instead of rear wall  14 . Tube  48  that supplies compressed air to the invention may be located on any of the walls. In  FIG. 2 , it can be seen that lips  50  and  52  are curved. Lips  50  and  52  are preferably slightly curved without any sharp angles. If lips  50  and  52  are angular, the web will be held less firmly against them. Although an angular shape for the lips may still work, the curved design is preferred. 
     FIG. 3  shows one method of opening and closing the invention. Clam shell  58  is rotatably attached to closing mechanism  104  by rod  136 . Similarly, clam shell  58  is also rotatably connected to closing mechanism  106  by rod  138 . Clam shell  60  is also rotatably attached to both closing mechanism  104  and mechanism  106  by rods  132  and  134  respectively. 
   Closing mechanism  104  is held in place by axle  108 . Axle  108  is rigidly connected to swinging arm  110 . Swing arm  110  is rotatably attached to locking arm  112  by pivot pin  114 . Similarly, swing arm  110  is rotatably attached to locking arm  116  by pivot pin  118 . To close the invention and press clam shells  58  and  60  together, axle  108  is rotated 180°. Groove  117  in locking arm  116  is slightly larger than axle  108  and allows locking arm to swing underneath axle  108  as swing arm  110  rotates 180°. Locking arm  112  has a similar groove on its bottom. As axle  108  and swing arm  110  rotate 180°, their pivotal engagement to lock arms  116  and  112  cause clam shell  58  to move in the direction of arrow  100  and clam shell  60  to move in the direction of arrow  102 . 
   Locking mechanism  106  operates in an identical but symmetric fashion. Axle  120  is rigidly engaged to swing arm  122 . Swing arm  122  is pivotally attached to lock arm  124  by pivot pin  126 . Swing arm  122  is also pivotally attached to locking arm  128  by pivot pin  130 . Locking arm  128  has a groove  129  slightly larger than axle  120 . Axle  120  rotates 180° simultaneously with axle  108 . When both axles have fully rotated 180°, clam shells  58  and  60  become engaged to one another to form an air tight chamber. Those skilled in the art will appreciate that locking mechanisms  104  and  106  are easily incorporated into existing packaging machines. It is preferred to have two mechanisms, one on each side of the clam shells, because this ensures an air tight seal between clam shells  58  and  60 . It is possible to utilize only one locking mechanism. However, those skilled in the art will appreciate that this will result is a less secure seal between the two clam shells. Those skilled in the art will appreciate that the locking mechanism shown in  FIG. 3  is only one of many possible methods for locking the two clam shells together to form an air tight chamber. Pistons, pneumatically driven or otherwise, may be used to push the two clam shell pieces together. Other methods are also known in the art. 
   In the figures, the walls that make up clam shells  58  and  60  are all at right angles to one another. However, those skilled in the art will appreciate that a variety of shapes are suitable for clam shells  58  and  60 . Typically, it is simpler and easier to manufacture the device such as this using flat parallepiped walls. However, the clam shells may be more hemispherical in shape if desired. 
     FIG. 4  shows an alternative embodiment of the present invention  150 . Alternative embodiment  150  is comprised of rounded clam shells  152  and  154 . 
   Whereas, the present invention has been described in relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.