Package making – Methods – Enclosing contents within progressively formed web means
Reexamination Certificate
2000-01-31
2002-04-09
Paradiso, John (Department: 3721)
Package making
Methods
Enclosing contents within progressively formed web means
C053S477000, C053S548000, C053S551000
Reexamination Certificate
active
06367230
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
The present invention relates to a method of forming, filling and sealing bags continuously and an apparatus for forming, filling and sealing bags. More specifically, the present invention relates to a method of packaging bags continuously in a bag-packaging machine that fills articles to be packaged in a bag while forming the bag by sealing portions of tubular packaging materials, where the tubular packaging materials are conveyed in a downward direction and are sealed after inserting articles therein. The present invention also relates to a bag packaging mechanism that packages bags by sealing portions of a tubular packaging material in longitudinal and latitudinal directions while inserting articles to be packaged therein.
B. Description of the Related Art
There has been a longitudinal bag-packaging machine that fills articles such as foods to be packaged in a bag while forming and sealing the bag.
For instance, a longitudinal pillow packaging machine forms a packaging material which is a sheet-shaped film into tubular shape by using a former and a tube. Longitudinal seal means seals (heat sealing) longitudinal edges of the tubular packaging materials that are placed one on top of another, thereby making bags. The pillow packaging machine fills articles to be packaged into the tubular packaging materials through the tube. Latitudinal sealing mechanism below the tube seals the upper portion of a bag and the bottom portion of a following bag. Then the pillow packaging machine cuts the middle of the latitudinally sealed portion. In such pillow packaging machine, operations of making a bag and filling articles in the bag occur in a continuous manner.
Some of such bag packaging apparatuses perform packing operations. Packing operations are especially important when articles to be packaged are small in apparent specific gravity but large in size. Examples of such articles include potato chips.
U.S. Pat. No. 4,391,081 and Japanese Laid-Open Patent Application Sho 63-191706 disclose such packing operation. In either method, a portion of the tubular packaging material to be sealed is pressed by stripper rods immediately before a pair of seal portions called seal jaws seals the tubular packaging material latitudinally by holding the tubular packaging material therebetween. In this manner, the portion to be sealed is pressed before the seal portions seal the portion, such that articles in that portion will be packed or pushed down (compressed) to a lower portion of the bag. Consequently, the packing operation attempts to prevent improper sealing that occurs due to some articles being sealed with the tubular packaging material at the time of sealing.
Problem to be solved by the Invention
Recently, there has been an increasing demand for bag packaging apparatuses that are capable of high speed processing. Consequently, there has been a need for high speed conveyance of tubular packaging materials and high speed processing by latitudinal seal mechanisms.
Accordingly, pressing operation also needs to be performed at a high speed. However, if packing operations are performed too fast, a bottom end of a bag which has already been sealed may burst or blowout because of an increase in the internal pressure of the bag during the packing operations performed at an upper end of the bag. The stripper rods in the Japanese reference mentioned above are urged by springs against the packaging material and therefore it is not possible to form a gap between the stripper rods in order to prevent such blowouts. Even if a gap were formed between ends of the stripper rods, thin articles such as potato chips may not be properly packed or pushed down, and some of the articles may remain in the sealing portion. This would nullify the purpose of pushing the materials in the bag away from the region of the sealing portion prior to sealing.
In view of the above, there exists a need for an improved latitudinal seal mechanism for a bag packaging apparatus which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
One object of the present invention is to enable latitudinal sealing without sealing articles to be packaged with the tubular packaging material, even when bags are packaged at high speed.
In accordance with one aspect of the present invention, there is a method of forming bags continuously, including inserting articles to be packaged in a tubular packaging material that is conveyed in a downward direction, and sealing the tubular packaging material to form a bag. The method includes the steps of:
inserting articles to be packaged in a partially formed bag;
sealing a lower end of the bag and an upper end of a preceding bag and simultaneously contacting a portion of the tubular packaging material that subsequently forms an upper portion of the bag in order to begin urging the articles downward.
In accordance with another aspect of the present invention, there is a method of forming bags continuously, including inserting articles to be packaged in a tubular packaging material that is conveyed in a downward direction, and sealing the tubular packaging material to form a bag. The method includes the steps of:
inserting articles to be packaged in a partially formed first bag before bottom and upper ends of the first bag are sealed;
sealing a lower end of the first bag and an upper end of a preceding bag and simultaneously contacting a portion of the tubular packaging material that subsequently forms an upper portion of the first bag in order to urge the articles downward, members contacting the portion of the tubular packaging material being spaced apart with a predetermined gap therebetween; and
sealing a lower end of a second bag and the upper end of the first bag and simultaneously contacting a portion of the tubular packaging material that subsequently forms an upper portion of the second bag in order to urge the articles downward, members contacting the portion of the tubular packaging material being spaced apart with a predetermined gap therebetween.
In accordance with yet another aspect of the present invention, there is a method of forming bags continuously, including inserting articles to be packaged in a tubular packaging material that is conveyed in a downward direction, and sealing the tubular packaging material to form a bag. The method includes the steps of:
inserting articles to be packaged in a partially formed first bag before bottom and upper ends of the first bag are sealed;
sealing a lower end of the first bag and an upper end of a preceding bag;
contacting a portion of the tubular packaging material that subsequently forms an upper portion of the first bag in order to urge the articles downward, members contacting the portion of the tubular packaging material being spaced apart with a predetermined gap therebetween;
inserting articles to be packaged in a partially formed second bag before bottom and upper ends of the first bag are sealed;
sealing a lower end of a second bag and the upper end of the first bag; and
contacting a portion of the tubular packaging material that subsequently forms an upper portion of the second bag in order to urge the articles downward, members contacting the portion of the tubular packaging material being spaced apart with a predetermined gap therebetween.
In the above methods, in each of the contacting steps, the members contacting the portion of the tubular packaging material move downward at a rate greater than a rate of downward movement of the tubular packaging material.
Preferably, each of the sealing steps further includes the steps of:
moving sealing members downward in a pre-pressing process on opposite sides of the tubular packaging material at a rate slightly higher than the rate of downward movement of the tubular packaging material with the sealing members spaced apart from each other by a predetermined gap; and
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Ishida Co. Ltd.
Paradiso John
Shinjyu Global IP Counselors, LLP
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