Patent Publication Number: US-6712510-B2

Title: Slider zipper package with wide mouth opening

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to reclosable packaging such as plastic pouches or trays and, in particular, to a reclosable package (and method of making the package) with a zipper having a slider which is constructed to prevent the slider from interfering with the filling or emptying of product from the package cavity. 
     Reclosable packaging has gained wide acceptance both for storage purposes and as primary packaging for foodstuffs and other commodities. The reclosable closures for such packaging consists of a pair of profiles having mating interlocking elements. It is becoming increasingly popular to provide a slider on the zipper to both facilitate opening and closing the zipper and to provide a visual indication of the condition of the zipper. While adding the slider to the zipper provides advantages to the package, the slider may reduce the effective length of the package mouth by protruding into the package opening. There is also the possibility of the slider inadvertently being displaced from the zipper by a user filling or emptying the package since, even when the slider is in the fully open position, the slider tends to block a portion of the mouth of the product cavity. 
     SUMMARY OF THE INVENTION 
     The above problems of the prior art are effectively resolved in accordance with the present invention by providing an improved package that is designed so that when the slider is in the zipper fully open position, it is parked in an area to the side of the product cavity. 
     The package has a front wall, a rear wall, bottom, top, and first and second sides. A zipper extends across the package top between the first side and the second side. A slider is disposed for movement along the zipper between a zipper fully open position when the slider is at the first side of the package, and a zipper fully closed position when the slider is at the second side of the package. A side seal is provided at the package first side joining the front wall to the rear wall and extending between the package bottom and the zipper. The side seal further extends toward the second side of the package for a distance at least as long as the length of the slider. In this manner, when the slider is in the zipper fully open position it parks above the side seal and out of the mouth of the package leading to the package product cavity. Additionally, the side seal may curve away from the zipper to an interior edge of the side seal. By extending the side seal away from the zipper in this manner, the area between the slider and the side seal is reduced without interfering with the movement of the slider. The tapered side seal and the reduced area between the slider and the side seal reduces the possibility that the product might be stuck in the area or caught by the side seal when being inserted or removed from the package. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
     FIG. 1 is a front view of a reclosable package in accordance with the present invention; 
     FIG. 2 is a side elevational view thereof; 
     FIG. 3 is a top view thereof; 
     FIG. 4 is a front view of a reclosable package in accordance with a second embodiment of the present invention; and 
     FIG. 5 is a schematic view of a representative manufacturing method. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference is now made to the drawings wherein like numerals indicate like elements throughout the several views, wherein FIG. 1 is a front view of the reclosable package  10  of the present invention. As shown in the figure, the package  10  has a front wall  12 , a rear wall  14 , a top  16 , a bottom  18  and opposed sides  20 ,  22 . A zipper  24  having mating interlocking members  26 ,  28  extends across the top  16  of the bag from the side  20  to the side  22 . A slider  30  is mounted on the zipper  24  to facilitate opening and closing the package  10 . When moved toward the side  20 , the slider  30  serves to disengage the interlocking members  26 ,  28 ; and when moved toward the side  22  the slider brings the interlocking members into engagement. End stops  32 ,  34  are provided at the ends of the zipper  24  to maintain the slider  30  on the zipper. 
     The front wall  12  of the package is sealed to the rear wall  14  of the package at the package bottom  18  by a seal  35  and is sealed at the package sides  20 ,  22  by side seals  36 ,  37 . A product cavity  38  is formed in the rear wall surrounded by seals  35 ,  36 , and  37 . A peel seal  39  extends across the package below the zipper  24  to provide tamper evidence and/or to permit the package cavity  38  to be hermetically sealed. The side seals  36 ,  37  include narrowed portions that extend to stops  32 ,  34  so as to provide continuous side seals from the package bottom  18  to the zipper  24 . 
     In accordance with the present invention the side seal  36 , which is at the zipper fully open side of the package, is formed wider than the length of slider  30 . As a result, when the slider is in the zipper fully open position it parks above seal  36  and out of the package mouth. That is, the slider parks totally to the side of the product cavity  38  and hence permits unencumbered access to and from the product cavity. The side seal  36  is sufficiently wide to accept a hang hole  40 . Alternatively a hang hole  42  (shown in phantom) may be provided in header  44  formed by a portion of the rear wall  14  that extends above the top of the front wall  12 . 
     In a further embodiment, the side seal  36  may be tapered in the parked area of the slider  30 . As shown in FIG. 4, the side seal  36  curves from a slider contact end  46  to an interior edge  45 . By extending the side seal  36  away from the zipper  24  in this manner, the area between the slider  30  and the side seal  36  is reduced without interfering with the movement of the slider. The tapered side seal  36  and the reduced area between the slider  30  and the side seal reduces the possibility that a product might be stuck in the area or caught by the side seal when the product is inserted or removed from the package  10 . 
     A representative method of forming the package  10  on a form, fill and seal machine  47  is shown schematically in FIG. 5. A base film  48  of thermoformable material for the package rear wall is fed from a supply spool  49  past a thermoforming station  50  where spaced pockets  52  are formed. As the formed film progresses, product  56  is fed through hopper  54  into each pocket. A zipper  24  having sliders  30  attached at spaced intervals is fed onto the base film from spool  62 . The zipper  24  may already be pre-shaped and crimped on the spool, or the zipper may be shaped and crimped at station  64  before it is applied to the base film. The shaping and crimping serves to flatten the ends of each length of zipper  24  so as not to interfere with the sealing of the zipper to the base and top films and to form the end stops  32 ,  34 , shown in FIGS. 1 and 4. A top film  68  for the package front wall is then fed from spool  69  over the base film  48 , capturing the zipper  24  between the top film and the base film. The films  48 ,  68  and the zipper  24  are then fed to a sealing station  70  where the side seals  36 ,  37  and the bottom seal  35  are formed by sealing the top and bottom films and the zipper is sealed to the films. At the same time the peel seal  39  may be formed between the zipper  24  and the product cavity  38  and air may be evacuated from the product cavity if desired. The individual sealed packages  10  are then removed by cutter  76  and any required hang holes are formed by punch  72 . 
     It should be apparent that packages in accordance with the present invention may be made by numerous other processes, either as part of a filling process or empty, and that the present invention is not limited to any particular method of manufacturing. What is important to the present invention is that the side seal at the zipper open side of the package be made sufficiently wide so as to permit the zipper slider to park over the side seal when the zipper is open. In that way, when the package is open the slider rests adjacent the product cavity of the package and does not protrude into the mouth of the package leading to the product cavity.