Abstract:
A zipper closure device for use with a turret type flexible pouch fill machine. The zipper closer device has a pair of rollers supported by an arm which is permitted to oscillate within a support module. The support module is mounted such that the rollers oscillate in a radial direction with respect to the access of rotation of the turret. The support module is supported by an arm in a post which permits positioning of the closer device with respect to the position of the pouches to be closed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    It is well known to produce plastic pouches with a plastic zipper. The zipper is formed from two interlocking strips of plastic. One strip is mounted to the inner side of one panel and the other strip is mounted on the inside of the after panel. A top seal is frequently formed on the pouch above the closed zipper. The pouches typically are filled with product and sealed on turret style machines in which the pouch is supported by a pair of grippers, each gripper holding a side seal of the pouch. The turret rotates to deliver the pouch through a number of stations where the pouch is opened, filled with product, and the zipper closed. Typically, the zipper is closed by a pair of wheels which are spaced apart so that there is a small gap between the circumferences of the wheels. The pair of wheels are supported above gripper to receive the top of the power. Rotation of the grippers pulls the top of the pouch with the zipper through the gap between the wheels. The wheels force the zipper elements together to close and seal the pouch. 
         [0002]    However, it is found that such an arrangement may unduly stress the pouch because the top of the pouch does not follow the circumference of the circle formed by the circular path traveled by the grippers. The top of the pouch is held by the grippers to extend in a straight line along a cord “c” formed between the grippers. As shown in  FIG. 5 , as the grippers follow the circular path “p”. The rollers pull the pouch away from the cord “c” to a distance “d” cord “c” between the grippers to the circumference. The deformation although small places undue stress upon the top of the pouch as it is stretched from the straight line cord to follow the circumference path of the rollers. 
       SUMMARY OF THE INVENTION 
       [0003]    A device for use with a rotating turret of a packaging machine for closing a zipper closure on a flexible pouch. The device includes a support module for supporting. A top end is pivotally mounted to the support module to permit at the lower end to oscillate radially in a radial direction with respect to a rotational axis of the turret. A pair of rollers are mounted to a lower end of the arm. The rollers are spaced apart to accept the pouch there between. The support module has an inverted u shaped cavity for accepting the top end of the arm. Adjustable stops are provided on the support module to limit the travel of the arm. The device may include the support for positioning the support module and arm over the circumference of the turret. The arm oscillates as the pouch enclosure is moved through the rollers such that the rollers, closure and top of the pouch are maintained on a straight line between the grippers during the closing process. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a top view of a fill machine turret with a zipper closer device in accordance with the invention. 
           [0005]      FIG. 2  is a perspective view of the support module in accordance with the invention. 
           [0006]      FIG. 3  is a perspective side view of the zipper closer device in accordance with the invention. 
           [0007]      FIG. 4  is a bottom perspective view of the zipper closer in accordance with the invention. 
           [0008]      FIG. 5  is a top view of prior art. 
           [0009]      FIG. 6  is a top view of the zipper closer device in operation in accordance with the invention. 
           [0010]      FIG. 7  is a cross-sectional view of a flexible pouch having enclosures. 
           [0011]      FIG. 8  is a side view of zipper closer during use. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    As shown in  FIGS. 1-4 , a novel zipper closer device  10  for a flexible pouch  12  includes support module  14  supporting an oscillating arm  16  having a pair of rollers  18 . The zipper closer device  10  is suitable for use with a turret style filling machine  20  ( FIG. 1 ). As shown in  FIGS. 2-4 , the arm  16  is pivotally supported as to permit the rollers  18  to oscillate radially inwardly and outwardly with respect to a rotational axis “a” of the turret as the pouch  12  passes through the rollers  18 . As shown in  FIG. 4 , the filling machine  20  has pairs of grippers  22  which support the pouch  12  in a straight line from gripper to gripper. The turret  20  moves the grippers  22  along a circular path “p” through a plurality of stations where the zippers are installed and the pouch is filled. The zippers are then closed by the zipper closer device  10 . 
         [0013]    As shown in  FIGS. 7 and 8 , the pouch  22  has a front panel  24  and a rear panel  26  of flexible material. A plastic zipper  28  is formed of a pair of interlocking strips  30  of plastic. One of the pair of strips  30  is mounted on the inner surface of each one of the panels  24 ,  26 . The strips  30  are mounted near the top of the pouch. 
         [0014]    As shown in  FIGS. 2 and 3 , the oscillating arm  16  is a rigid elongated member having a top  32  and a bottom  34 . The top  32  has an inverted U-shape with a bore  34  for mounting to a pin  38  of the support module  14 . The top  32  is supported so that the arm  16  can oscillate from side to side with respect to a vertical axis “y”. 
         [0015]    As shown in  FIGS. 3, 4 and 8 , a plate  40  is mounted to the bottom  34  of the arm  16  for pivotally supporting the pair of rollers  18 . The rollers are separated by a distance equal to the width of the pouch with the zipper  28  so that as the top of the pouch is pulled through the zippers the force of the rollers  18  pushes the strips  30  together. The rollers  18  have a generally cylindrical resilient surface  42  formed of rubber or the like. In order to minimize the distance of travel of the rollers during oscillation the arm is provided with a long length, such as of approximately 170 millimeters. This results in the rollers oscillating through a relatively small number of degrees. 
         [0016]    As shown in  FIGS. 2 and 8 , the support module  14  is block shaped having a top  44 , a front wall  46  and a pair of end walls  48 . The front wall  46  has an inverted u-shaped recess  50 . The recess  50  is defined by a curved top wall  52  and a pair of side walls  54 . The pivot pin  38  for supporting the arm  16  is positioned in the recess  50 . A threaded stop pin  56  extends through each of the end walls  45  to side walls  54  of the support module top  30  to the arm  16 . The threaded pins are threaded to move inwardly and outwardly to act as stops for the pivotal movement of the arm. Knurled grips  58  are fixed to each of the pins  56 . A third pin  60  extends vertically from the top  44  into the recess  50 . The pin  60  is made of a hard plastic such as Delrin and can be adjusted to put tension on the top  32  of the arm so as to dampen the movement of the arm  16  as it oscillates. 
         [0017]    As shown in  FIG. 3 , the support module  14  is mounted to a cross member  62  which extends on a horizontal axis from an upright post  64 . The post  64  extends vertically from a base  66  or from the machine housing. A double tube clamp  68  has one clamp portion which extends about the post  64  and a second clamp portion for adjusting the position of support member  14  and rollers  18 . The clamps have pins  70  which extend through clamps to tighten or loosen the clamp to allow vertical adjustment along the post and along the cross post in an inward and outward position with respect to the turret. 
       OPERATION 
       [0018]    As shown in  FIGS. 6 and 8 , the pouch  12  is supported for rotation by the turret  20  by the pair of grippers  22 . The top portion and zipper  28  of the pouch  12  extend above the grippers  22 . The grippers  22  rotate on the circular path “p” about a center axis “a” of the turret. The pouch is positioned on a straight line which lies on a cord “c” of the circular path “p” of the grippers  22 . The cord “c” has a height “h” or maximum distance between the path “c” and top of the pouch  12 . The support arm  16  and rollers  18  are permitted to oscillate from the vertical axis “y” which passes through the pivot axis “b” of the arm. As shown in  FIG. 6 , the rollers oscillate distance equal to the cord height “h”. However, because the rollers can oscillate in two directions from the vertical axis, the distance of travel in each direction is ½ “h” in one direction and ½ “h” in the other direction. As shown in  FIG. 6 , the pivot axis “b” is then positioned so that the vertical axis “y” of the arm is ½ “h” inwardly of the path “p” of the grippers. As shown in  FIG. 8 , when the pouch  12  enters the rollers  18 , the arm  16  immediately pivots radially inwardly to ½ “h”. The path of the rollers has the shape of a sine wave. The arm returns to the vertical axis “x” as the rollers  18  move along the top of the pouch positioned on cord “c”. The arm and rollers  18  then move opposite direction ½ “h” which is at the cord height “h”. The arm  16  then oscillates back to center and to the start position where the panel exits the rollers. The distance ½ “h” is relatively small distance typically in the range of 0.008-012 inches. 
         [0019]    As shown above, the zipper closer apparatus provides a simple, efficient and fully adjustable zipper closer which follows the straight line path of the pouch through its zipper closing operation. The zipper closer reduces the stress that is put on the top and ensures that proper force is maintained on the zipper as it is being closed. 
         [0020]    Although discussed with respect to the above preferred embodiment, it will be apparent to those skilled in the art that many variations are possible within the scope of the invention.