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INFLATED DUNNAGE AND METHOD FOR
ITS PRODUCTION
Matter enclosed in heavy brackets [ ] appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.
This application is a reissue of Ser. No. 081659,576 filed on Jim. 6, 1996 now U.S. Pat. No. 5,693,163, which is a continuation-in-part of Ser. No. 08/317,760 filed Oct. 4, 1994, now U.S. Pat. No. 5,552,003.
BACKGROUND OF THE INVENTION
The invention relates to a process for producing dunnage directly on the site of use, and the dunnage produced thereby.
Materials with low density and high volume are commonly used as packing materials to insulate goods being shipped from shock. Among the materials used are polystyrene "peanuts", "cups" and "worms," pellets of foam rubber, foam plastics and expanded polyurethane foam. Air cushioning material is generally preferred over the above types of dunnage because it is lighter in weight, can be supplied and dispensed in a controlled manner, particularly in web or folded form, and applied to the product to be shipped in sheet form. The sheet form of material is also easier to dispose of than the individual pieces of plastic dunnage after the product is removed, and the sheet form of material can be rewound for further use or disposed of by deflation.
However, air cushioning material also presents a variety of problems, as large volumes of the material must be kept on hand, and due to the necessity of shipping this material from the producer, shipping costs can be considerable.
In order to overcome these problems, devices have been proposed to produce sealed air dunnage on site from plastic sheets. U.S. Pat. No. 5,188,691, 5,203,761, and 4,576,669 all propose devices for producing air filled dunnage, typically bubble wrap, from plastic sheets on an "on demand" basis.
U.S. Pat. No. 3,575,757 discloses a process for producing dunnage on site from plastic sheets in which opposed sheets are bonded together in a U-shaped seal to form a pocket, the pocket is inflated and then sealed by the formation of a subsequent U-shaped seal.
However, the above methods of producing dunnage are somewhat disadvantageous, as the apparatus necessary to handle two separate sheets of plastic is somewhat complex and difficult to operate. When used on site, it is typically operated by people whose expertise is not in the production of dunnage and who have some difficulty operating the equipment at peak efficiency.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to produce dunnage on site in a simplified manner.
It is a further object of the invention to provide dunnage on site by a method which can be operated easily by personnel without expertise in the production of dunnage.
To achieve these and other objects, the present invention provides a method for producing dunnage comprising the steps of providing, in web form, a plurality of preformed plastic bags, each of the bags comprising two plastic sheets in facing relationship and sealed along three edges thereof with one edge remaining open, the bags having slip resistant outer surface and being releasably attached in sequence
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along two opposed edges, blowing air toward each said open edge causing each bag to inflate in sequence, sealing the fourth edge of each inflated bag, the bag being empty except for air during the sealing operation, separating sealed
5 inflated bags from the web of bags and placing a plurality of separated sealed bags in a carton to serve as dunnage.
Applicants have discovered that it is far more difficult to produce a web of plastic bags than it is to convert a web of plastic bags to inflated dunnage. Therefore, according to the
1° method of the invention, a web of preformed bags is manufactured separately by those with the greatest expertise. This web of bags is formed by placing a plastic sheet in facing relationship with another plastic sheet and forming a plurality of bags along the sheets by sealing along three
15 edges with one edge remaining open. The plurality of bags is packaged, such as by rolling up or fan-folding, and transported to the site where the dunnage is to be produced.
Applicants have further discovered that by making the surface of the bags slip resistant, the dunnage which is
20 produced with such bags will interlock in use and serve to better protect objects contained with the dunnage from shock. Accordingly, the invention further relates to a container containing a plurality of inflated and sealed plastic bags, the bags having an outer surface which is slip resistant
25 and thereby causes the bags to interlock around the object to be protected.
In addition, applicants have discovered that the interlocking of the bags increase the volume of air between the bags, and thereby reduces the number of bags necessary to fill a carton of given volume. While the amount of the reduction may vary, in one instance the number of bags necessary was reduced by 12%.
In order to further reduce the number of bags necessary to
35 fill a carton, it is possible to coat or line the carton with a slip resistant material.
Typically, a web of bags will be provided to the site where dunnage is to be produced which is segmented longitudinally, but a web can also be provided which is
40 segmented both longitudinally and laterally, to produce a web with, for example, four bags across or eight bags across. The bags can be separated from the web individually and placed in a carton, or can be separated in groups of at least two bags, and typically more. This is advantageous, as the
45 dunnage which is produced can be wrapped around an object and taped together just as bubble wrap would be, and which is as easy to dispose of or reuse as bubble wrap (or even easier). The inflated dunnage of the invention is, however, much easier to produce than bubble wrap.
50 A variety of techniques and materials may be used to manufacture the slip resistant bags of the invention. The term "slip resistant" is intended to apply to several different surface conditions from highly tacky and adhesive to simply co-adhesive, where the bags are not tacky at all, but adhere
55 to each other.
One layer or mono-film extrusion is the most basic method for forming a slip resistant surface. There are many plastics that are slip resistant in their natural unaltered state, the most common of which is low density polyethylene.
60 Low density polyethylene is commonly manufactured with additives that increase its "slip" but the invention can utilize low density polyethylene without such additives. While use of a single layer of slip resistant polyethylene is possible according to the invention, it is not preferred as bags formed
65 of a single layer of this material are slip resistant on the inner surface as well as the outer surface, and the surfaces are therefore difficult to separate for inflation.
