Package making – Methods – Forming a cover adjunct or application of a cover adjunct to...
Reexamination Certificate
2002-12-17
2004-07-13
Sipos, John (Department: 3721)
Package making
Methods
Forming a cover adjunct or application of a cover adjunct to...
C053S389200, C053S451000
Reexamination Certificate
active
06761012
ABSTRACT:
BACKGROUND OF THE INVENTION
Mesh bags are used to package many different products, for instance, children's toys, small hardware items, flower bulbs, nuts, fruits and vegetables. Plastic bags made with thermal sealable films (both solid and perforated) are also used to package many of these same items. Mesh bags and perforated film bags allow air to flow through the package. Perishable items such as flower bulbs, nuts, fruits, and vegetables are often packaged in mesh or perforated film because they benefit from the airflow.
Vertical form, fill and seal machines are widely used in the packaging industry. They are widely used because they reduce packaging costs, especially labor costs associated with loading or filling premade bags.
Thermoplastic films, both solid and perforated, have been widely used on vertical form, fill, and seal machines for more than 20 years. Mesh materials have generally not been used on vertical form, fill, and seal machines because they are difficult to process on vertical form, fill, and seal equipment.
Typical mesh materials have a significantly higher degree of open air space between strands (openness) than do perforated films. This is true because typical mesh films are composed of thin strands. This is also true because there is a limit to the size and number of perforation holes that can be used before a perforated film loses its tensile strength, tear resistance, and dimensional stability. For example, a typical 10 lb. plastic bag having a length of 18″ and a width of 10″ for fresh whole potatoes might have 12 holes punched for ventilation approximately 0.375″ diameter. This is equivalent to 0.4% is the surface area of the plastic film on both-sides of the bag. Whereas a mesh material such as the preferred CLAF mesh is at least 50% open. The resultant step change in openness for mesh materials significantly increases airflow through the mesh package compared to a perforated film package.
The thin strands of typical mesh materials also reduce the surface area inside the package where moisture and condensation can be trapped and collect. Entrapped moisture and condensation inside the package are generally believed to increase spoilage and/or decrease shelf life for most perishable items, particularly whole potatoes and onions packed fresh or from storage.
The combination of increased airflow through the package is and reduced entrapment of moisture inside the package is desired by most packinghouse operators, distributors, and marketers of perishable fruit and vegetables.
Heretofore, the use of mesh materials on vertical form-fill-seal machines has been limited due to concerns about heat seal failures and overall package integrity. The most common failures are in either (1) the mesh-to-mesh transverse fin seals, and/or (2) the mesh-to-mesh longitudinal lap (or fin) seals. Failures of mesh-to-mesh heat seals are common in the predominant package weights ranging from one pound to ten pounds. In the majority of attempts to use mesh materials on vertical form-fill-seal machines, the package either fails at or adjacent to the transverse fin seal, at or adjacent to the longitudinal lap (or fin) seal, or both. The primary reason for mesh-to-mesh heat seal failures is the lack of an adequate and consistent mass of thermal sealable plastic material in the desired heat seal area.
Although there are distinct advantages to the use of mesh materials for such packages, for many of the above-described reasons, perforated films are typically chosen over mesh for use on vertical form-fill-seal machines when perishable items are being packed.
The grower-shippers and packing facilities that package perishable items have also imposed additional demands for increased packing and filling speeds for pre-made bag filling equipment and automated form-fill-seal packing equipment. In either case, filling premade bags or filling on vertical form, fill, and seal machines, the larger the fill opening for the items to be packed, the greater the filling speed.
Typically, the length of a bag is greater than its width. That being the standard, there is an advantage to filling the bag through the side as opposed to filling through the top. Regardless of the filling method employed (manual, semi-automatic, or fully automatic) the vast majority of all bags are filled through the top of the bag, thus the
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opening size for placing articles in the bag is limited by the top circumference dimension of the premade bag or vertical form, fill, and seal package. Thusly, the speed of packing is also limited.
Fox U.S. Pat. No. 6,190,044 indicates examples of typical premade bag sizes indicating horizontal (width) and vertical (length) dimensions of the side walls (sides) for various produce weights as follows:
Produce
Cross Sectional Area
Weight
Bag Wall Dimensions
Top Fill
Side Fill
2 pounds
10″ horizontal by 16″
31.41 square
50.26 square
vertical
inches
inches
3 pounds
10.5″ horizontal by
32.98 square
50.26 square
16″ vertical
inches
inches
5 pounds
10.5″ horizontal by
32.98 square
59.68 square
19″ vertical
inches
inches
10 pounds
13″ horizontal by 23″
40.84 square
72.25 square
vertical
inches
inches
Note:
the horizontal dimensions above are the bag tops & bottom and the vertical dimensions above the bag left & right sides
It is clear from the cross sectional area that the openings for filling through the sides are significantly greater the openings for filling top. Those skilled in the art of operating packaging equipment would easily recognize the advantages of being able to automatically fill packages with articles through the larger side opening of the package rather than through the smaller top opening of the package.
Grower-shippers and packing facilities that package perishable items have also imposed additional demands on packing equipment manufacturers for reduced equipment cost, increased packing and filling speeds, increased efficiency, increased flexibility, and reduced waste during the packing processes. This is true for packing machines designed and used for packing pre-made bags, as well as for vertical form, fill, and seal 1 packing machines.
In recent years, particularly in Europe, new vertical form, fill, and seal machines designed to run mesh materials have been introduced to the market by Pannekeet Machine Techniek of The Netherlands, Sorma Netpack of Italy, and Affeldt Verpackungsmaschinen GmbH of Germany. For the most part, these are machines that are designed for the primary purpose of running mesh with large labels front and back, the use of labels being advantageous to reinforce the mesh-to-mesh transverse heat seals. The fact that they require large labels, however, adds significant cost to the final package. There is also the burden of added capital investment for the packing house operator if he has to purchase special vertical form, fill and seal machines designed primarily to run mesh material only.
WO9914121 (EP 0 677 450 A1) is directed to the utilization of a mesh web on vertical form, fill, and seal machines made by Pannekeet Machine Techniek of The Netherlands and Affeldt Verpackungsmaschinen GmbH of Germany specifically for improved packaging of perishable items. WO9914121 (EP 0 677 450 A1) provides that the top and bottom mesh-to-mesh heat seals of the vertical form, fill, and seal package are reinforced by positioning a large film label on both the front and back of the package sandwiching a mesh tube in-between. The front and back labels run the full length and nearly the full width of the lay-flat package. Aside from advertising, the primary purpose of the front and back label is to reinforce and prevent the top and bottom heat seals from failing. While this method may reduce heat seal failures typical of most mesh-to-mesh seals, it falls short because its advantages are offset by the following deficiencies:
(1) the bag must be filled through the narrow top opening; thereby, limiting filling speeds;
(2) the finished bag must be gusseted on both sides i
Debnam Warren H.
Rusert Craig R.
Atlanta Nisseki CLAF, Inc.
Kaplan Barry E.
Myers & Kaplan LLC
Patel Ashish D.
Sipos John
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