Method for applying soft cap to slider or zipper with mounted slider

Abstract

The disclosure pertains to methods for inserting a soft cap onto a slider in order to protect the slider from damaging the package film of a reclosable bag during high pressure pasteurization. A first embodiment discloses manual or automated insertion of the soft cap onto the slider, prior to inserting the slider/cap assembly onto a length of zipper. A second embodiment discloses automated insertion of the soft cap onto a slider which is already mounted on a length of reclosable zipper. A third embodiment uses an insert molding process with a first mold cavity to form the slider and a second mold cavity to form the soft cap over the slider. A fourth embodiment uses a dual shot molding process in a single mold cavity to form both the slider and the soft cap thereover.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to methods for application of a soft cap to protect a slider from damaging the package film during high pressure pasteurization. The methods involve the placement of the soft cap onto the slider either before or after the slider is placed onto the zipper assembly.

2. Description of the Prior Art

High pressure pasteurization (HPP) of food-containing packages is accomplished by placing the package in a chamber that is typically raised to 85,000 psi for a predetermined time period. Typical reclosable food packaging with “press to close” zippers will survive high pressure pasteurization. However, packages containing slider zipper assemblies have proven to be problematic. The zippers are typically enclosed in the packaging by the top portion of the packaging film, known as the shroud. During the high pressure pasteurization process, the extreme pressure pushes the shroud film onto the slider with such force as to punch holes in the film, rendering the package useless.

Commonly assigned U.S. patent application Ser. No. 11/020,607 entitled “Sleeve Cover for Slider”, filed on Dec. 23, 2004, the contents of which are hereby incorporated by reference, discloses a semi-soft sleeve cover to shield the slider during high pressure pasteurization. Likewise, commonly assigned U.S. patent application Ser. No. 11/103,751 entitled “Reclosable Package with Slider Zipper Shielded for High Pressure Pasteurization”, filed on Apr. 12, 2005, the contents of which are hereby incorporated by reference, discloses a shrouded reclosable bag wherein the slider shield is secured to the tear-away header so that the slider shield and the tear-away header are removed as a single piece.

While these solutions are effective for their intended purpose, further improvements are desired with respect to the automated placement of the soft cap onto a slider or zipper with a mounted slider, particularly in combination with form fill and seal methods.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide improvements in the methods relating to the manual or automated placement of a soft cap onto a slider or zipper with a mounted slider, in order to protect the slider from damaging the plastic packaging film during high pressure pasteurization.

This and other objects are attained by several embodiments of the present invention.

In the first embodiment, the soft cap is pre-formed and placed onto the slider either manually or by a machine that individually places the cap onto the slider. The machine method orients the slider in a fixed position so that the soft caps can be mounted onto the sliders in a consistent fashion. Typically, sliders and caps are placed in separate vibratory bowls to orient the parts into the assembly equipment. The finished slider/cap assembly is then mounted to the zipper assembly.

In the second embodiment, the soft cap is placed by a machine onto the slider, after the slider has been mounted onto a zipper assembly. The machine aligns the cap over the slider and then pushes the cap onto the slider.

In the third embodiment, the soft cap is molded over the slider by an insert molding process, whereby the slider is molded in a first mold cavity and then placed into a second mold cavity where the soft cap is molded onto the slider.

In the fourth embodiment, the soft cap is molded in place by a dual shot injection molding process, whereby the slider and the cap are sequentially injected into a common mold cavity.

DESCRIPTION OF THE DRAWINGS

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings:

FIG. 1 is a perspective view of the soft cap being positioned near the slider prior to insertion thereon, in the first embodiment of the present invention.

FIG. 2 is a perspective view of the soft cap inserted onto the slider, in the first embodiment of the present invention. Additionally shown are two vibratory bowls for the automated process.

FIG. 3 is a perspective view showing a machine inserting the soft caps onto sliders which are mounted on a zipper, in the second embodiment of the present invention.

FIGS. 4A, 4B and 4C are perspective views, partially in phantom, showing the sequential stages of an insert molding process for a soft cap on a slider, in the third embodiment of the present invention.

FIG. 5 is a perspective view, partially in phantom, showing a dual shot injection molding process for slider and soft cap formation, in the fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings in detail wherein like numerals indicate like elements throughout the several views, one sees that FIGS. 1 and 2 illustrate the first embodiment of the present invention. In the first embodiment, slider 100 is provided, prior to insertion onto a zipper. Slider 100 is well-known to those skilled in the art of zippers for reclosable bags. Likewise, pre-formed soft cap 200 is provided. Soft cap 200 is disclosed in U.S. patent application Ser. No. 11/020,607 entitled “Sleeve Cover for Slider”, filed on Dec. 23, 2004, and U.S. patent application Ser. No. 11/103,751 entitled “Reclosable Package with Slider Zipper Shielded for High Pressure Pasteurization”, filed on Apr. 12, 2005, the contents of both of which are hereby incorporated by reference. Soft cap 200 is configured to engage slider 100.

FIG. 2 illustrates the soft cap 200 after it has been pushed onto slider 100. This may be done manually, or it may be done with an automated reciprocating insertion device 20, similar to that shown in FIG. 3 for the second embodiment. Such a machine method orients sliders 100 in a fixed position so that soft caps 200 can be mounted onto the sliders 100 in a consistent manner. Typically, sliders 100 and soft caps 200 are placed in separate vibratory bowls 30, 32, respectively to orient the parts into the assembly equipment. Subsequently, the finished slider/cap assembly shown in FIG. 2 would be mounted onto a zipper assembly. The first embodiment is advantageous in that it avoids any damage to a zipper assembly.

FIG. 3 illustrates a second embodiment of the present invention wherein a reclosable zipper 300 is provided with the sliders 100 already mounted thereon. An automated reciprocating insertion device 20, comprising head 22 which engages the soft cap 200 and reciprocating rod 24 which moves the head 22 back and forth, is shown. Automated reciprocating insertion device 20 further includes vibratory bowl 32 which dispatches soft caps 200 to head 22.

FIGS. 4A, 4B and 4C illustrate the sequence of insert molding for the soft cap 200 on slider 100. In FIG. 4A, slider 100 is formed in a first mold cavity 400, typically by injecting plastic through passageway 401. Those skilled in the art, after review of this disclosure, will recognize that there are many possible molding techniques available for this process. In FIG. 4B, slider 100 is shown placed into second mold cavity 402. In FIG. 4C, the material for soft cap 200, such as another plastic or silicone, is injected through passageway 403 into second mold cavity 402 over slider 100 thereby forming soft cap 200 over slider 100. Subsequently, the finished slider/cap assembly shown in FIG. 4C would be mounted onto a zipper assembly.

FIG. 5 shows dual injection mold cavity 500 wherein a first plastic is injected through first passageway 502 to form slider 100. Thereafter, a second plastic is injected through second passageway 504 to form soft cap 200 over slider 100. Subsequently, the finished slider/cap assembly shown in FIG. 5 would be mounted onto a zipper assembly.

Conventional form fill and seal methods, and other methods, may be used to incorporate the slider/cap assembly into a finished and filled reclosable plastic bag which is thereafter exposed to high pressure pasteurization.

Thus the several aforementioned objects and advantages are most effectively attained. Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.

Claims

1. A method including the steps of:

providing a slider;

providing a cap to protect said zipper slider during high pressure pasteurization; and

inserting said cap over said slider.

2. The method of claim 1 wherein said step of inserting is done manually.

3. The method of claim 1 wherein said step of inserting is performed by an automated device.

4. The method of claim 3 wherein said automated device includes a first vibratory bowl and a second vibratory bowl, said step of providing a slider is performed by said first vibratory bowl and said step of providing a soft cap is performed by said second vibratory bowl.

5. A method comprising the steps of:

providing a slider on a length of reclosable zipper;

providing a cap to protect said slider during high pressure pasteurization; and

inserting said cap over said slider while said slider is on said length of reclosable zipper.

6. The method of claim 5 wherein said step of providing a cap is performed by a vibratory bowl.

7. The method of claim 5 wherein said step of inserting said cap is performed by a reciprocating device.

8. The method of claim 7 wherein said reciprocating device includes a reciprocating rod attached to a head, said head engaging said cap.

9. A method comprising the steps of:

molding a slider in a first mold cavity;

moving said slider to a second mold cavity;

molding a cap around said slider in said second mold cavity, said cap to protect said slider during high pressure pasteurization.

10. The method of claim 9 wherein said steps of molding are performed with injection molding.

11. A method comprising the steps of:

molding a slider in a mold cavity;

molding a cap around said slider in said mold cavity, said cap to protect said slider during high pressure pasteurization.