Patent Publication Number: US-2005139607-A1

Title: Flexible pouch fitment structure

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates to fitments and in particular to a spout fitment for a flexible package.  
      Fitments are often used to provide a pouring spout for containers formed of flexible films. It has heretofore been proposed to use a fitment/spout with a canoe-shaped base that serves to provide a smooth, gradual transition between the plies of film from which the package is to be formed and the pouring spout which is coaxial with the center of the fitment. Common wisdom taught that the fitment canoe section should be relatively rigid so as not to misshape the center spout section when the fitment is subjected to the heat and pressure needed to seal the package film to the fitment. This, in turn, required that the sealing jaws as well as the fitments be precisely sized to assure the formation of tight seals. Frequently it is necessary to attach the fitment with one set of sealing jaws and then seal the pouch film with a second different set of jaws. Unfortunately, in practice, fitments injection molded of polyethylene, polypropylene and the like often vary somewhat dimensionally during manufacture. Also, in time, the sealing jaws wear and such wear may not be uniform. As a result, during such package manufacturing, unreliable welds result and there is a failure to obtain consistent packages. This is counterproductive to the desired production rates for the packages formed utilizing such fitment attachment processes.  
      The attachment of such fitment is disclosed in U.S. patent application Ser. No. 09/452,714 entitled “Method for Attaching Fitment at Longitudinal Fin Seal and Package Resulting Therefrom” filed on Dec. 2, 1999. A thin wall fitment is disclosed in U.S. patent application Ser. No. 09/643,033 filed Aug. 21, 2000 entitled “Thin Wall Fitment for Spouted Pouch”. Other prior art includes U.S. Pat. No. 5,911,340 entitled “Spout Assembly, Spout Assembly Manufacturing Apparatus and Package with Spout Assembly” issued on Jun. 15, 1999 to Uematsu; U.S. Pat. No. 5,716,471 entitled “Method for Securing Articles to Laminates” issued on Feb. 10, 1998 to Pape; U.S. Pat. No. 4,909,434 entitled “Moisture Impervious Carton Having One-Piece Pouring Spout Sealed to Innermost and Outermost Surfaces” issued on Mar. 20, 1990 to Jones et al.; U.S. Pat. No. 3,894,381 entitled “Method and Means for Attaching Fitments to a Bag or Pouch on a Packaging Machine” issued on Jul. 15, 1975 to Christine et al.; and U.S. Pat. No. 5,855,544 entitled “Flexible Container With Tubular Fitment And Method And Apparatus For Assembling Same” issued on Jan. 5, 1999 to Buchanan.  
     OBJECTS AND SUMMARY OF THE INVENTION  
      It is a principal object of the present invention to provide an improved fitment with canoe-shaped walls which can be installed at relatively high speeds with a single set of sealing jaws.  
      A further object is to provide such a fitment wherein the canoe-shaped walls are designed to distort during the installation process so as to facilitate and enhance sealing of the associated package film to the fitment side walls.  
      A still further object is to provide a method of and apparatus for sealing a fitment to a package film that ensures the formation of tight seals between the fitment and package film.  
      The above and other beneficial objects and advantages are attained in accordance with the present invention by providing a flexible plastic fitment. The fitment includes side walls having a center portion comprising diametrically opposed segments of a common cylinder and straight segments that blend respectively into the cylindrical segments on opposite sides of the common cylinder and are joined together at both ends thereof in a pointed tip thereby forming a canoe shape. A cover joins the top edges of the canoe shape and extends at both ends of the canoe shape between the cylindrical segments and the pointed tip. A thin fin at each end of said joined side walls, said fins comprising extensions of said pointed tips.  
      The fitment is attached to an associated film package by inserting the fitment between facing sheets of the film forming the package, substantially aligned with edges of the facing sheets. Prior to that a mandrel is inserted into the center of the common cylinder of the fitment. The mandrel may be dimensioned to distend the fitment side walls&#39; cylindrical segments and straight segments outwardly which causes accurate positioning of these surfaces. While the mandrel is positioned within the common cylinder and distending the cylindrical segments and straight segments of the side walls outwardly, heated sealing jaws close to capture the film sheet edges against the fitment to seal the film edges to the side walls. In this regard, the sealing jaws includes convex sections out-of-line with the mandrel which urge the packaging film inwardly as the sealing jaws close to thereby enhance the contact of the fitment and packaging film and thereby compensate for any dimensional intolerance.  
      It is usually desirable to simultaneously contact the package film, thus sealing the film surface at the top of the pouch at the same time as attaching the fitment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In the accompanying drawings:  
       FIG. 1  is a perspective view of a fitment in accordance with the present invention;  
       FIG. 2  is a perspective view of the fitment of  FIG. 1  in position to be sealed between sheets of a packaging film, for clarity, the top sealing jaw has been partially removed;  
       FIG. 3  is a bottom (viewed from the fitment) plan view of the fitment of  FIG. 1  in position to be sealed to packaging film, for clarity, the bottom sealing jaw has been partially removed; and  
       FIG. 4  is a perspective view of a package formed by the sealing equipment of  FIG. 2  utilizing the fitment of  FIG. 1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Reference is now made to the drawings and to  FIG. 4  in particular wherein a package  10  is depicted. The package is formed of two sheets of a suitable film for the contents to be held. In this regard, the film may be a laminate, the layers of which have desired barrier or other properties for the product to be contained and an appropriate sealant layer for bonding to each other and to the fitment. The sheets are sealed to each other in a zone  12  extending about the package periphery, thereby forming a leak proof inner area  14  into which the package contents are captured. A spout  16  extends from the package top to the inner area  14 . The spout  16  conveniently includes a center cylindrical neck  18  which carries external threads  20  for an associated cap. The spout  16  is formed using a fitment  22  as shown in  FIG. 1 . Fitment  22  is conveniently injection molded of a thermoplastic material such as polyethylene or polypropylene and the canoe section is relatively thin, on the order of 26-28 mils.  
      Fitment  22  comprises a cylindrical neck  18  which extends upwardly from a canoe-shaped base  24 . The canoe-shaped base  24  consists of side walls  26 ,  28  each of which is formed of a curved center portion  30 ,  32  into which straight segments  34 ,  36  and  38 ,  40  tangentially blend. The side walls  26  and  28  are joined at both ends at a point from which a thin fin  42 ,  44  extends. It is important to note that there are no internal ribs or gussets supporting the side walls and that the only support comes from cover sections  46 ,  48  (see  FIG. 2  and  FIG. 3 ) at the top of the canoe. As a result the fitment side walls are quite flexible and resilient. To facilitate attaching the fitment to the packaging film a series of raised horizontal ribs  50  extend about the side walls from end to end. Because of the relatively low mass of the ribs  50 , they readily fuse with the packaging film when the heated sealing jaws are activated. The speed of the fusing is further assisted by the mass of the canoe side walls  26 ,  28 ,  34 ,  36 ,  38  and  40  acting as a heat sink to encourage rapid solidification of the ribs as the jaws open. A flange  52  extends radially outwardly from cylindrical neck  18  between the canoe side walls and the area of cap threads  20  of the cylindrical neck. The flange  52  serves to facilitate feeding the fitment for attachment to the packaging film and accordingly is designed to properly orient the fitment during the attachment process.  
      Reference is now made to  FIG. 2  wherein the sealing jaws  54 ,  56  and mandrel  58  of the sealing apparatus used to join the fitment  22  to the sheets of packaging film  60 ,  62  are depicted. It should be appreciated that for clarity only the bottom sealing jaw  54  and bottom film  60  are shown in detail. The top sealing jaw  56 , which is identical to the bottom sealing jaw  54 , but inverted, and top film  62 , are cut away. It will also be appreciated that the mandrel  58  is oblong and oversized. As a result, when the mandrel is inserted into the fitment  22  the side walls  26 ,  28  are stretched over the mandrel surface providing highly controlled and accurate positioning of that portion of the canoe base. It should be further noted that sealing jaws  54 ,  56  which have mating sections  72  that are generally contoured to receive the fitment, also have convex sections  64 ,  66 , such convex sections will contact the unsupported sections of the canoe ( 38 ,  40 ) driving heat and pressure into said portions of the canoe until the sealing jaws  54 ,  56  are clamped on the melting fins  42 ,  44 . As the fins melt away the pouch film surface is pressurized and the top of the pouch is sealed. This results in a highly controlled and predictable relationship which consistently produces a secure seal being formed between the fitment and the packaging sheets even if there are minor dimensional variations or other distortions in the fitment. The sealing jaws  54 ,  56  further include flat sections  68 ,  70  on opposite sides of section  72  that is contoured to receive the fitment. When the sealing jaws close, the flat sections  68 ,  70  seal together the top edges of the packaging film on both sides of the fitment to form the top  74  of the package  14  while simultaneously securing the fitment to the package. In this connection, the fins  42 ,  44  at the ends of the canoe serve to permit a smooth transition between the sheet sealing and fitment sealing by the jaws. To further facilitate sealing of the film sheets the mandrel may be heated.  
      Thus, in accordance with the above, the aforementioned objects are effectively attained.