Cushioned Shipping Bag

Abstract

A shipping bag has two outer bag walls and at least two layers of a cushioning material which provide means for sealing the outer bag walls together at the peripheral edges thereof. A method for making the bag is also disclosed.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a cushioned shipping bag construction.

Many articles, such as books, electronic components and the like, require a shipping bag that provides a good degree of protection when the article is being shipped through the mails or by various transportation means. Because of the high volume involved with such articles, these shipping bags must also be easily and cheaply mass produced.

One of the cushioned shipping bags presently available for these purposes employs a side-wall construction having two kraft sheets joined together at their peripheral edges, with a loose cushioning material sealed therebetween. Two of these side walls are then folded together and joined to form the shipping bag. An example of this type of bag is disclosed in U. S. Pat. No. 3,055,575 to Gerard. The cushioning material first used in these bags were various forms of "batting;" more recently, macerated newsprint has been used in order to reduce the cost of the bag.

However, shipping bags constructed in this manner are relatively heavy and unduly add to postal and shipping costs. The macerated newsprint tends to "bunch" in one location and reduce the overall protection afforded the article enclosed. Frequently, one of the outer kraft sheets is breached in transit or upon receipt, and the macerated newsprint is inadvertantly spilled. In addition, the seams of prior art shipping bags are often poorly sealed, thus exposing the article enclosed to moisture damage under the adverse humidity conditions frequently encountered during shipping. Further, the method for making prior art shipping bags is relatively complicated, requiring several separate cutting, folding, and glueing operations.

THE DRAWING

FIG. 1 illustrates a cross-section of a shipping bag in accordance with the present invention.

FIGS. 2a and 2b are top plan views of two embodiments of the bag shown in FIG. 1, in which the magnified cross-section of FIG. 1 is taken along the lines 1--1'.

FIG. 3 illustrates a cross-section of an alternate embodiment of a shipping bag in accordance with this invention.

FIG. 4 is a cross-section of another embodiment of a shipping bag according to this invention.

FIG. 5 is a top plan view of manufacturing apparatus, shown by block diagrams, and materials used in a method for making the shipping bag of FIGS. 1 and 2a.

FIG. 6 is a side view of the apparatus and materials shown in FIG. 5.

DETAILED DESCRIPTION

The shipping bag of the present invention will be described with reference to FIGS. 1, 2a, and 2b.

Noting FIG. 1, the shipping bag, referred to generally as 10, includes two opposing outer bag walls 12 and 14 which are substantially parallel to each other. The walls 12, 14 may be a variety of materials. Preferably, the walls 12, 14 are a material which is readily heat sealed, such as paper with at least the inner side coated with a very thin layer of a poly-resin, such as a low-density polyethelene resin, for example. In the embodiment of FIG. 1, such inner poly-resin layers 13 and 15 are associated with the walls 12 and 14, respectively,

The bag 10 also includes two sealable cushioning layers 16 and 18 between the two walls 12 and 14, each of which extends along the innermost side of the adjacent bag wall to the peripheral edge thereof, and are each substantially the same width and length as the adjacent bag wall. Suitable materials for the cushioning layers 16,18 include a variety of heat-sealable resinous cushioning materials, such as any of the commercially available porous polyethelene, polyurethane, polystyrene, or polypropelene resins; particularly suitable, however, is a porous polypropelene resin known as "Microfoam Sheeting," which is manufactured by E. I. duPont Inc., of Wilmington, Del. A densified sealed joint 22 of the cushioning layers 16 and 18 joins the peripheral edge 20 of the two bag walls 12 and 14 together. When the thin poly-resin layers 13 and 15 are employed, the peripheral portions of these layers are integral with the sealed joint 22. The two bag walls 12,14 and the cushioning layers 16,18 thus define a protected enclosure 24 which is especially suitable for shipping relatively fragile articles. As can be appreciated by those skilled in the art, the porous cushioning layers 16,18 provide the desired shock absorbency behind the bag walls 12,14 and simultaneously provides a moisture-resistant seal at the joint 22.

The densified sealed joint 22 may completely join the peripheral edge 20 on all four sides of the bag 10. Such an arrangement is illustrated in FIG. 2a; suitably, one of the sides would be sealed by the shipper after the article is placed inside the enclosure 24. Alternatively, as shown in FIG. 2b, one of the bag walls 14 may be somewhat longer than the other bag wall 14, to provide a flap 26 which can be folded over and stapled or glued to the other wall 12 after the article to be shipped is inserted in the enclosure 24.

An alternate embodiment of the shipping bag 10 of FIG. 1 is shown in FIG. 3, and referred to generally as 30. In this embodiment, two outer bag walls 32 and 34 are formed from a single sheet of material, as the paper described above, which is folded at an intermediate point 36. Cushioning material having the same characteristics as that of the cushioning layers 16,18 of FIG. 1 is likewise folded to provide two cushioning layers 38,40 each next adjacent one of the bag walls 32,34 and which define a protected enclosure 42. The bag walls 32,34 are then joined together at the peripheral edges 44 by a sealed joint 46 of the cushioning layers 38,40.

Another embodiment of the shipping bag is shown in FIG. 4, and is referred to generally as 31. The shipping bag 31 is similar to the bag 10 of FIG. 1, except that two additional bag walls, as walls 33 and 35, are disposed on the inside of the cushioning layers 16,18. Each inner wall 33,35 has dimensions somewhat less than the cushioning layers 16,18 and the outer walls 12,14, and are also sealed within the sealed joint 22.

A method for mass producing a large number of the shipping bags will now be described with reference to FIGS. 5 and 6. The manufacturing apparatus employed in this method is well-known in the bag manufacturing industry, and is therefore identified in FIGS. 5 and 6 by block diagrams and descriptive legends only.

As clearly shown in FIG. 6, four machine rolls 51-54 are mounted in successive elevated relationship, as on a bag machine backstand (not shown). The lower and upper rolls 51 and 54 each comprise a single rolled sheet 56 of a material suitable for use as the bag walls 12,14 in the bag 10 shown in FIG. 1. The two inner rolls 52 and 53 each comprise a rolled sheet 58 of a heat sealable cushioning material, such as any of the materials described above.

The four sheets 56,58 are extended in substantially one direction "d," so that the two cushioning sheets 58 are "sandwiched" between the two wall sheets 56. The four sheets 56,58 are then pulled through any one of a variety of standard longitudinal pressing and heating apparatus 60, either the jaw or roller type, to press te four sheets 56,58 together along their peripheral edges 62 and along preselected lines intermediate to the two edges and substantially parallel to the one direction "d." Simultaneously, the cushioning sheets 58 are heated and melted at the edges 62 and along these intermediate lines. When the sheets 56,58 pass out the apparatus 60, the melted cushioning material is cooled and densified, forming peripheral sealed joints 64 along the peripheral edges 62 and intermediate sealed joints 65 along the intermediate lines (note FIG. 5). In order to facilitate the cutting operation described below, the intermediate sealed joints 65 are somewhat wider than the peripheral joints 64.

At this point, the sealed sheets 56,58 can be passed directly to a cutting apparatus 68, which cuts along each intermediate joint 65 to separate the sealed sheets into a number of peripherally sealed, uncut "tubes," which are then rolled onto a spool. These tubes can then be delivered "as is," allowing the user to cut shipping bags to any desired length, after which both ends of the bag are sealed.

Alternatively, prior to the cutting operation, the sealed sheets 56,58 can be passed from the longitudinal pressing and heating apparatus 60 to transverse pressing and heating apparatus 72, preferably of the stamping type which will form, in a single operation, a sealed joint across the sheets 56,58 without requiring the interruption of the movement of the sheets. Thus, the transverse heating apparatus 72 seals the sheets together along a series of joint lines 74 which are substantially transverse to the one direction "d." The sheets 56,58 are then passed through a perforator 76 to cut a series of perforations 78 intermediate to adjacent transverse sealed joints 74 and also to cut perforations 80 along each transverse joint. The resulting perforated and sealed sheets 56,58 are then passed through the cutting apparatus 68 to cut along the intermediate longitudinal joints 65 and form a number of strips 82 containing a quantity of individual shipping bags similar to the bag 10 of FIGS. 1 and 2a, but with side unsealed. Each strip 82 is then rolled onto a spool (not shown).

In use, the shipper tears the outermost shipping bag from the strip 82 at one of the perforations 78 or 80, inserts the article to be shipped, and closes the open end, as by heat sealing or stapling, for example.

The shipping bag described above is relatively light in weight and provides a high degree of shock absorbency over the entire bag. Further, the resinous cushioning material, in providing the desired shock absorbency, simultaneously provides a densified sealed joint at the periphery of the bag which has a very high degree of moisture resistance. The shipping bag of this invention also avoids the difficulties with the macerated newsprint and "batting" heretofore used in shipping bags. In addition, the shipping bag can be easily and cheaply mass-produced by the method described.

Claims

I claim:

1. A shipping bag construction, comprising:

two outer poly-coated paper bag walls;

two inner poly-coated paper bag walls,

a layer of resinous cushioning material interposed between and laminated to each inner and outer wall, each said cushioning layer having dimensions approximately equal to the dimensions of said outer walls; and

said cushioning layers being joined together along the periphery of the bag by a densified sealed joint,

the periphery of each of said inner walls extending to but not included in said joint.