Abstract:
A method of sealing a plug with a food sauce dispensing cartridge enables leak proof operation of the dispensing cartridge at the site of the plug. The plug, having a circumferential edge, is positioned within the dispensing cartridge and oriented such that the edge is adjacent to the cartridge sidewall. A layer of hot melt adhesive is then applied to the circumferential edge and flows into a gap created between the plug and the cartridge sidewall at a sideseam formed by an overlap region of the cartridge sidewall. The hot melt adhesive subsequently bonds the plug to the cartridge sidewall and prevents food sauce from moving past the circumferential edge of the plug and out of a containment region.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     None. 
     BACKGROUND OF THE INVENTION 
     Food sauce dispensing cartridges are used throughout the food service industry for dispensing a measured quantity of sauce on a food item. As an example, in fast service restaurants, a large volume of food items must be prepared for customers in a relatively short around of time. Meeting this demand presents a significant challenge; consistent food quality can only be achieved by dispensing the correct amount of sauce, but the fast pace of preparing food items leaves little time to carefully measure dispensed amounts. The use of handheld dispensing guns with food sauce dispensing cartridges has enabled consistent and fast dispensing of sauce amounts to allow greater quantities of food items to be prepared within a narrow timeframe. The exact quantity of sauce dispensed by the cartridge is controlled by valves formed in the dispensing end of the cartridge and the degree of motion of the dispensing gun acting on a plug in the cartridge being advanced towards the dispensing end. Each time a trigger of the dispensing gun is pulled, the gun advances the plug a consistent distance. 
     Typically, food sauce dispensing cartridges are fabricated from paper stock with opposing ends folded together in a continuous loop sidewall such that the ends overlap one another and are adhered together to form the cartridge in a cylindrical shape. This overlap creates a sideseam that runs the length of the container. Additionally, the outer and interior surfaces of the cartridge are typically coated with a thermoplastic liner. The plug is most often formed of a thermoplastic or other similar plastic. 
     While advancements have been made in the design and manufacture of end caps containing the values disposed at the dispensing end of the dispensing cartridges, problems remain with methods of sealing the plug with the cartridge to prevent leaks at the plug. Although plugs are often bonded with the interior surface of the dispensing cartridge before use with a dispensing gun, the bond must release enough to allow the gun to advance the plug through the cartridge while at the same time maintaining a seal such that food sauce within the cartridge may not pass by the peripheral edge of the plug and escape out of the containment region. One common method of bonding the plug is to heat the flanged perimeter edge of the plug (e.g., with hot air) such that the plastic melts and bonds with the thermoplastic liner of the cartridge. This method, however, does not provide a leak proof seal for typical dispensing cartridges. This is because the internal sideseam of the cartridge causes the interior diameter thereof to vary as much as the sidewall thickness of the container from a point where the sidewall overlap occurs to a point adjacent to the sideseam. The plug on the other hand has a consistent diameter around the peripheral edge, and the melting of the flanged edge is not sufficient to fill a gap created between the peripheral edge and the cartridge sidewall at a point immediately adjacent to the sideseam. Thus, as the dispensing gun advances the plug, food sauce escapes the cartridge not only at the intended dispending end, but also by bypassing the periphery of the plug along the sideseam towards the opposing end. Also, the gap may present an additional path for contaminants to enter the containment region of the cartridge. 
     BRIEF SUMMARY OF THE INVENTION 
     In light of the aforementioned problems, the present invention provides an improved method of sealing a plug with a food sauce-dispensing container whereby leakage in the plunging region is eliminated. A plug with a body and a peripheral skirt is first positioned within a plunging end of a dispensing container such that the circumferential edge of the plug on the peripheral skirt is aligned generally in a plane perpendicular to the longitudinal axis of the container. The plug is generally sized with a diameter about the same as the average diameter of the dispensing container so that it may be frictionally fit therein, leaving a gap between the circumferential edge of the plug and the container sidewall adjacent to the container sideseam. Subsequently, a layer or bead of hot melt adhesive is applied to the circumferential edge of the plug to bond the plug with the dispensing container sidewall. The adhesive also flows into the gap between the plug and the container to prevent food sauce disposed in a containment region between the plug and an end disk at the dispensing end of the container from escaping around the periphery of the plug. The bonding or sealing of the plug may take place before the end disk is connected to the dispensing container, or preferably, is done at the last step of dispensing container construction after end disk connection is complete. 
     With the method of dispensing container construction taught by the present invention, less food sauce product is wasted and there is less risk of food contamination because the open channel or gap to the containment region around the plug is eliminated. In use, as the user pulls the trigger on the dispensing gun to advance the plug, the pressure within the containment region between the plug and the end disk will increase. Because the plug is bonded to the container sidewall using the hot melt adhesive which fills the gap created at the sideseam, the plug seal can withstand the pressure increase without failing so that the food sauce is only dispensed properly out of the valves in the end disk. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       In the accompanying drawings which form a part of the specification and are to be read in conjunction therewith and in which like references numerals are used to indicated like parts in the various views: 
         FIG. 1  is a side elevational view of an exemplary dispensing cartridge construction having a plug sealed therewith in accordance with one embodiment of the present invention, with the cartridge applied to a dispensing gun and shown partially in section; 
         FIG. 2  is a perspective view showing the dispensing cartridge of  FIG. 1 ; 
         FIG. 3  is a fragmentary partial sectional view on an enlarged scale showing the relationship between disk, the adhesive and the cartridge body; and 
         FIG. 4  is a cross-sectional view taken along line  4 — 4  showing the sideseam of the cartridge body and the gap filled by the adhesive. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A disposable food sauce cartridge dispenser  10  of the type utilizing the method of the present invention to seal a plug  12  therewith is shown in  FIG. 1 . The dispenser  10  is generally comprised of a cartridge body  14 , an end disk  16  formed at a dispensing end  18  of the dispenser, and the plug  12  which is initially positioned at the plunging end  20  of the dispenser opposite of the dispensing end. A containment region  22  is defined within the cartridge body  14  between the plug  12  and the end disk  16  in which a volume of food sauce  24  is packaged and from which the food sauce may be dispensed through the end disk  16  by operation of a hand held dispensing gun  26 . One exemplary arrangement for a dispensing gun  26  is shown, but forms no part of the present invention and is merely illustrated to show generically how the plug  12  may be advanced towards the end disk  16  to dispense food sauce  24 . The manner in which the exemplary dispensing gun  26  operates is more fully disclosed in U.S. Pat. No. 4,432,473. The dispensing gun  26  is configured to receive the plunging end  20  of the dispenser  10  between a pair of flanged plates  28 . The gun  26  includes a plunger  30  that fits against the plug  12  and may be advanced towards the dispensing end  18  by squeezing a trigger  32  that operates a ratchet mechanism  34 . For each trigger squeezing cycle, the ratchet mechanism  34  advances the plunger  30 —and thereby the plug  12 —a pre-selected distance into the dispenser  10  based on the magnitude of the trigger squeeze, up to a set maximum, resulting in the dispensing out of valves (not shown) in the end disk  16  of a measured quantity of the food sauce  24 . 
     The plug  12  and cartridge body  14  are similar to those used in typical food sauce cartridge dispensers that are known in the art; however, the plug  12  has modifications that distinguish the plug from typical designs, as will be more fully explained herein. The configuration of the plug is best seen in  FIGS. 2 and 3 , and the construction of the cartridge body  14  is best seen in  FIGS. 2 and 4 . 
     The cartridge body  14  is preferably formed of paper stock with opposing ends  36  folded together in a continuous loop sidewall  38  such that the ends overlap one another and are adhered together (e.g., with adhesives) to form the cartridge body  14  in a cylindrical shape presenting an interior surface  40  and an exterior surface  42 . The interior surface  40 , and optionally the exterior surface  42 , is typically coated with a thermoplastic liner. The section of the sidewall  38  where the ends  36  overlap is referred to as the overlap region  43 . This overlap also forms an interior sideseam  44  and an exterior sideseam  46  that extend longitudinally along the sidewall parallel to a central longitudinal axis of the cartridge body  14 . 
     The plug  12  has a body  48  that is generally disk-shaped with certain raised and depressed regions so that the plunger  30  of the dispensing gun  26  will better interface with the plug  12  and provide smooth dispensing operation. A peripheral skirt  50  extends generally perpendicularly from the body  48  and terminates at a smooth perimeter or circumferential edge  52 . The skirt  50 , or some portion therealong (e.g., circumferential edge  52 ), preferably has a diameter that is approximately the same as the average interior diameter of the cartridge body  14  so that the plug  12  may be loosely frictionally fit within the body prior to the plug being bonded with the interior surface  40 . However, the plug diameter may be smaller or greater than the cartridge body  14  average interior diameter so long as there is not excessive friction between the plug  12  and the cartridge body interior surface  40  that would impede the desired operation of the dispensing gun  26 . Plugs known in the art typically have an outer edge that tapers to a fine flange extending away from the body of the plug and having a much reduced thickness as compared to the thickness of the peripheral skirt. However, the smooth circumferential edge  52  of the plug  12  in the present invention presents a broader surface to which an adhesive  54  may be applied to bond the plug  12  with the cartridge body interior surface  40 , as best seen in  FIG. 3 . Although the circumferential edge  52  is shown to be curved, it may also be formed at a right angle facing generally perpendicularly from the remaining portion of the peripheral skirt  50  and presenting a surface as broad as the thickness of the skirt. 
     As can be seen in  FIG. 4 , because of the interior sideseam  44 , the interior diameter of the cartridge body  14  is not identical at all points. In the overlap region  43 , the cartridge body  14  has a first diameter value that is generally consistent around a majority of the interior surface  40  of the body, and has a second diameter value larger than the first diameter value at a location proximal to the point where one of the overlapping ends  36  passes over and to the exterior of the other end  36  (i.e., laterally on the other side of the interior sideseam  44  from the overlap region  43 ). However, the plug  12  is generally circular and thus has a consistent diameter at least at some point on the peripheral skirt  50 , preferably at least at the circumferential edge  52 . Thus, when the plug  12  is placed in the cartridge body  14 , the “step” in diameter created at the interior sideseam  44  forces the circumferential edge  52  radially inward at the location of measurement of the second diameter and forms a open channel or gap  56 . 
     Thus, to assemble the cartridge dispenser  10 , the first step is to position the plug  12  within the cartridge body  14  such that the circumferential edge  52  of the plug is aligned generally in a plane perpendicular or transverse to the central longitudinal axis of the body (i.e., perpendicular to the sidewall  38 ) and concentric with the interior surface  40 , as seen in  FIG. 4 . At this point, the plug circumferential edge  52  is preferably immediately adjacent to the interior surface  40  for essentially the entire edge  52  so that the plug is not tilted relative to the cartridge body  14 . The plug  12  is also preferably positioned initially near the dispensing end  18  of the dispenser  10  until it is later acted upon by the dispensing gun  26 . Adhesive  54  is then applied to the circumferential edge  52  of the plug  12  to properly bond the plug  12  to the cartridge body interior surface  40  and to fill the gap  56  to prevent food sauce  24  from passing out of the containment region  22  around the plug  12 . The adhesive  54  is preferably a food grade hot melt adhesive such as a thermoplastic adhesive, but may include other similar adhesives that include waxes, resins and plasticizers. The hot melt adhesive generates a bond with the thermoplastic liner formed on the interior surface  40  of the body  14  that is not so strong as to unreasonably inhibit the dispensing gun plunger  30  from advancing the plug  12  towards the dispensing end  18 , but has sufficient strength and structural integrity as to not be deflected laterally from the interior surface  40  by food sauce pressing thereagainst when the plunger  30  is advanced and the pressure within the containment region  22  is increased. The adhesive  54  is preferably applied as a continuous bead around the circumferential edge  52 , and may be applied sparingly directly into the gap  56  as well so long as the adhesive properly cures before running into the containment region  22  or has sufficient viscosity as to only travel a certain distance into the gap  56  short of region  22 . After the adhesive  54  has properly cured, the cartridge dispenser  10  is ready for use in conjunction with a dispensing gun  26 . Preferably, the end disk  16  is secured to the cartridge body  14  before the plug  12  is bonded with the body. The end disk may be secured to the body  14  using known top crimping methods, or other methods known by those of skill in the art. 
     An alternative method of cartridge dispenser  10  assembly involves reversing the steps of plug  12  insertion and adhesive  54  application. Thus, the adhesive  54  (e.g., a food grade hot melt adhesive) may first be applied to the circumferential edge  52  of the plug  12 , and then the plug  12  is quickly placed within the cartridge body  14  near the dispensing end  18  of the dispenser  10 . The plug  12  should be aligned generally in a plane transverse to the central longitudinal axis of the cartridge body  14  and concentric with the interior surface  40 , as seen in  FIG. 4 . For this method, the adhesive  54  should be of the type that does not cure instantly upon application to the plug  12 , but gives sufficient time for insertion and proper alignment of the plug  12  within the cartridge body  14  before bonding with the body interior surface  40 . Also, either sufficient adhesive  54  should be applied to the plug circumferential edge  52  so that gap  56  will be covered once the plug  12  is properly positioned in the cartridge body  14 , or extra adhesive  54  may be applied directly over the gap  56  once the plug  12  is set in place. 
     Since certain changes may be made in the above invention without departing from the scope hereof, it is intended that all matter contained in the above description or shown in the accompanying drawing be interpreted as illustrative and not in a limiting sense. It is also to be understood that the following claims are to cover certain generic and specific features described herein.