Flexible pouch fitment structure
A flexible plastic fitment for providing spouts for pouches formed of sheet material. The fitment includes a pair of opposed side walls each having a center portion formed from diametrically opposed segments of a common cylinder and straight segments that blend respectively into the cylindrical segments on opposite sides of the common cylinder. The side walls are joined together at both ends thereof to form a canoe shape. A cover, which provides the only support for the side walls joins the top edges of the canoe shape and extends at both ends of the canoe shape between the cylindrical segments and the joined ends. A thin fin extends from each end of the joined side walls. A method of and apparatus for attaching the fitment by distending the side walls outwardly while urging the sheet material toward the side walls is also disclosed.
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' 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:
Reference is now made to the drawings and to
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
Reference is now made to
Thus, in accordance with the above, the aforementioned objects are effectively attained.
8. The method of securing a fitment to a package including the steps of:
- providing two facing sheets of packaging material;
- inserting a mandrel into a fitment so as to distend said fitment cylindrical segments and
- inserting a fitment between said facing sheets substantially aligned with edges of said facing sheets, said fitment having side walls formed of diametrically opposed segments of a common cylinder and straight segments blended respectively into said common cylinder segments, said side walls being joined together at both ends thereof thereby forming a canoe shape;
- sealing said facing sheet edges to said side walls while said fitment cylindrical segments are outwardly distended by said mandrel.
9. The method in accordance with claim 8 wherein said facing sheet edges are sealed to said fitment cylindrical segments by opposed sealing jaws closing toward each other from opposite sides of said mandrel.
10. The method in accordance with claim 9 wherein said sealing jaws each include a section generally contoured to include convex portions which are designed to engage and seal the resilient portions of the canoe walls outside of the cylindrical area.
11. The method in accordance with claim 10 wherein said mandrel is heated.
12. In combination for the sealing of a fitment between facing packaging sheets, said fitment having side walls formed of diametrically opposed segments of a common cylinder and straight segments blended respectively into said common cylinder segments, said side walls being joined together at both ends thereof thereby forming a canoe shape:
- a mandrel for insertion between said side walls, said mandrel being dimensioned to distend said fitment side walls outwardly; and
- opposed sealing jaws adapted to close toward each other from opposite sides of said mandrel, said sealing jaws having contoured sections to urge said facing sheets toward said fitment when said sealing jaws are closed.
13. The combination in accordance with claim 12 wherein said sealing jaws' contoured sections each include convex sections out-of-line with said mandrel when said jaws are closed, said sealing jaws' convex sections urging said facing sheets toward said fitment as said sealing jaws close.
14. The combination in accordance with claim 13 further comprising flat sections of said sealing jaws on opposite sides of said contoured sections.