Dunnage air bag

Details Dunnage air bag Dunnage air bag

1997-12-19

2001-02-13

Gordon, Stephen T. (Department: 3612)

Freight accommodation on freight carrier

Yieldable brace

Panel

C410S125000

Reexamination Certificate

active

06186714

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to dunnage air bags for use in connection with the shipment of freight or cargo by means of truck, rail, aircraft, ship, and the like, and more particularly to an improved dunnage air bag which exhibits improved burst strength characteristics.
BACKGROUND OF THE INVENTION
Inflatable, disposable dunnage bags comprise a relatively inexpensive and easily useable means for stabilizing cargo or freight disposed within cargo holds, cargo bays, cargo containers, box-cars, trailers, or the like, of aircraft, trucks, trains, ships, or other transportation vehicles, so as to effectively prevent the goods from being damaged which is likely to occur when the goods are not otherwise secured or tied down within the cargo hold or the like since the goods are subjected to shifting movements within the cargo hold or bay in response to movements of the particular transportation vehicle during shipping or transport. As is well known and conventionally practiced in the transportation industry, and as is exemplified by
FIG. 1
, inflatable dunnage bags
10
are placed between individual, adjacent cargo items or pieces
12
, or between the individual cargo pieces and the side walls
14
of the vehicle within which the cargo hold
16
is defined, in an initially deflated condition and are then subsequently inflated with, for example, compressed air to a predetermined pressure value which is of course below the bursting pressure limit of the bag. Most bags which are conventionally employed are specifically constructed so as to be capable of withstanding bursting pressure values which are within the range of 12-30 psig. As is also illustrated, sheet or board-type buffer members
18
are also sometimes placed between the dunnage bags
10
and the cargo loads
12
. One type or embodiment of a conventional dunnage bag is disclosed within U.S. Pat. No. 4,136,788 which issued to Robbins on Jan. 30, 1979.
Another conventional dunnage bag similar to that of Robbins is illustrated at
10
in FIG.
2
and is seen to comprise a sealed inner plastic bladder or bag
22
which is fabricated, for example, from polyethylene, and an outer multi-layered or multi-walled paper bag
24
that serves to protect the inner inflatable bag or bladder
22
as well as to increase the burst strength characteristics of the dunnage bag
10
. In the exemplary dunnage bag
10
illustrated in
FIG. 2
, the outer multi-walled or multi-layered paper bag
24
is seen to comprise, for example, four paper plies or layers
1
,
2
,
3
,
4
.
Manufacture of such conventional inflatable dunnage bags typically comprises folding a predetermined length of multi-layered kraft paper onto itself and about a longitudinal axis thereof such that the edges thereof can form an overlapping longitudinal seam, not shown, which extends along the centerline of the multi-walled or multi-layered paper bag
24
, the result being a multi-walled or multi-layered paper tube having opposite open ends. The sealed plastic bladder
22
is then inserted into the paper tube through one of the open ends thereof, and the tube ends are then folded over onto themselves in a predetermined manner and are subsequently glued closed thereby forming the completed dunnage bag
10
.
In accordance with the particular exemplary mode of folding and sealing each end of the multi-walled or multi-layered paper bag
24
, and with only one end of the multi-walled or multi-layered paper bag
24
being illustrated in
FIG. 2
, it is seen that each paper ply or layer
1
,
2
,
3
,
4
of the multi-walled or multi-layered paper bag
24
has a first end respectively denoted by the reference characters
1
A,
2
A,
3
A,
4
A, and a second opposite end respectively denoted by the reference characters
1
B,
2
B,
3
B,
4
B. The ends
1
B,
2
B and
3
B of the paper plies or layers
1
,
2
,
3
are freely disposed atop each other, while the end
1
A of paper ply or layer
1
is freely disposed or inserted beneath end
1
B. Ends
2
A,
3
A, and
4
A of paper plies or layers
2
,
3
, and
4
are also disposed atop each other, however, it is seen that end
2
A of paper ply
2
is fixedly secured to end
3
B of paper ply
3
by means of a first glue bead
26
, end
3
A of paper ply
3
is fixedly secured to end
2
A of paper ply
2
by means of a second glue bead
28
, and end
4
A of paper ply
4
is fixedly secured to end
3
A of paper ply
3
by means of a third glue bead
30
. The outer surface of paper ply
4
is also conventionally coated with a suitable heat-sealable plastic, such as, for example, polyethylene, in order to provide the dunnage bag
10
with a predetermined amount of water-resistance, and accordingly, end
4
B of paper ply
4
is disposed atop end
4
A of paper ply
4
and the ends
4
A and
4
B may then be heat-sealed to each other by means of well-known heat-sealing techniques.
In order to inflate the interior portion of the dunnage bag
10
with a suitable compressed gas, such as, for example, air, from an external compressed air source, not shown, when it is desired to inflate the dunnage bag
10
, that is, for example, for cargo securing purposes, an inflation valve
20
is provided and is heat-sealed upon the upper wall
22
B of the inflatable bladder
22
such that the valve
20
is in fluidic communication with the interior of the bladder
22
. It is also seen that the inflation valve
20
extends or projects through respective holes
1
C,
2
C,
3
C, and
4
C provided within the ends
1
B,
2
B,
3
B, and
4
B of the paper plies or layers
1
,
2
,
3
,
4
of the multi-walled or multi-layered paper bag
24
whereby the inflation valve
20
is rendered externally accessible.
It is well-known in the industry, however, that the region of an inflatable, multi-ply or multi-layered kraft paper dunnage bag, such as that exemplified and shown in
FIGS. 1 and 2
at
10
, which comprises the glued flap region at which, for example, the ends
2
A,
3
A, and
4
A of the paper plies
2
,
3
, and
4
are glued and sealed together and to the ends
3
B and
4
B of the paper plies
3
and
4
, respectively, comprises a high-stress region at which stresses, forces, and internal pressures attendant the inflation of the dunnage bag
10
are concentrated. An important factor to be considered or which is required to be addressed in connection with such multi-ply or multi-layered kraft paper dunnage bags resides in the tendency of the multi-layered or multi-ply flaps to unfold or separate not only from each other but also as an entity from the main portions or sides of the bags. The structural integrity of such region determines, in part, the burst strength of the bag
10
.
It is also noted that such multi-ply or multi-layered kraft paper dunnage bags, such as that shown and exemplified in
FIGS. 1 and 2
at
10
, differ radically from what is known in the industry as abrasion-resistant air bags as exemplified or disclosed within U.S. Pat. No. 4,591,519 which issued to Liebel on May 27, 1986. Air bags such as those disclosed within the noted patent are used in connection with relatively light weight or low-pressure applications, such as, for example, those applications requiring working or inflation pressures of 1-3 psi, and it is seen that such air bags are constituted or constructed from first and second sheets
16
and
24
of two-ply laminated paperboard. Such paperboard is quite stiff or rigid and in effect self-sustaining whereby the air bags may be able to stand by themselves without sagging even prior to inflation of the same and disposition between cargo loads. The folded side and end sections
18
and
26
therefore do not present the same stress, force, and internal pressure characteristics or factors which are encountered in connection with the folded flaps of a multi-layered or multi-ply kraft paper bag as has been illustrated in
FIGS. 1 and 2
at
10
.
Another factor which determines or affects the burst strength characteristics of the dunnage bag
10
is the provision of the inflation valve
20
, and more particularly, its relative loca

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