It is conventionally known in the cargo transportation art to use inflatable airbags in order to properly brace a transportable load, such as, for example, large paper rolls in order to prevent any shifting of the cargo loads during the transportation of the same so that the loads do not become damaged. Such conventional airbags usually consist of a single, inflatable, thermo-plastic bladder surrounded by or encased within some type of container, such as, for example, a multi-ply paper container. The container effectively prevents the inflatable bladder from being punctured by the load or other objects which may be located within the cargo bay. The inflatable airbag of course includes an air inlet valve so that the inflatable bladder may be readily inflated.
In order to properly brace a load using the aforenoted single type of airbag, specially contoured roll buffers or chocks, as shown in FIG. 5, are additionally required in order to positionally hold or retain the airbag between the load rolls or between a load roll and a wall of the cargo bay. As can be appreciated from FIG. 5, the specially contoured roll buffers or chocks have a particular configuration or shape which complements or conforms to the shape or configuration of the load rolls and are therefore able to positionally retain the airbag and load rolls essentially fixed with respect to each other. Still further, additional dunnage is often needed to be interposed between the buffers or chocks and the airbag in order to pad or serve as shock absorbers or friction dissipators at the point of contact defined between the airbag and the contoured load roll buffers or chocks. If the load roll buffers or chocks, as well as the additional dunnage, were not employed within the load or cargo system, the airbag would have a tendency to positionally move with respect to, and even become disengaged from its position between, the load rolls.
When the single type of conventional bladder airbag is employed in connection with the bracing of loads during transportation of the same, the airbag is initially interposed between the specially contoured roll buffers and additional dunnage, in a deflated condition, and is subsequently inflated through means of its air inlet valve with high pressure air to a predetermined air pressure value or level, such as, for example, 2-8 psi depending upon the size of the airbag bladder and its surrounding container structure. When so disposed in its inflated condition, any voids otherwise existing between the load rolls are automatically filled or effectively eliminated, and in addition, the load rolls are effectively stabilized and readied for transportation of the same under conditions which will prevent substantial movement thereof and consequent damage thereto.
While such conventional bladder airbag systems have of course functioned well or properly from a purely operational viewpoint, it has been previously realized that such structural systems do present other problems from, for example, an economic transportational point of view. For example, since such conventional systems require the use of such specially contoured roll buffers and additional dunnage, the latter structures add significant amounts of weight to the overall weight of the cargo actually being transported, however, such additional weight does not constitute actual cargo for which transportation customers will pay shipping charges. Considered from a converse standpoint, the buffers and dunnage constitute cargo load or weight, and require additional cargo load space, which could otherwise be used in connection with actual transportation customer cargo loads.
In view of the foregoing, the aforenoted prior related patent application was directed toward the disclosure of a dual bladder airbag whereby the aforenoted deficiencies of the conventional or prior art type of bladder airbag system would be overcome and rectified, such as, for example, the additional specially contoured chocks or load roll buffers, along with the attendant dunnage, would be able to be eliminated. Briefly, in accordance with the invention disclosed within the prior related patent application, a pair of overlapping, inflatable bladders are incorporated within a relatively non-elastic container, and when the bladders are inflated, the overall external configuration of the bladders-container structure includes oppositely disposed concave surface portions which engage external peripheral portions of the cargo load rolls or drums whereby the bladders-container structure will not only fill the voids existing between adjacent cargo load rolls or drums, but in addition, such structure, by itself, that is, without the need for any additional chocks, buffers, and dunnage, cooperates with the cargo load rolls or drums so as to not only stabilize the cargo load rolls or drums, but such intercooperative cargo structures serve to effectively retain the bladders-container structure between the cargo load rolls or drums without movement of the bladders-container structure with respect to the cargo load rolls or drums or without the bladders-container structure undergoing undesirable disengagement from its position between the cargo load rolls or drums. Consequently, it has been found that the dual bladder airbag system of the prior related patent application has been quite successful in overcoming and rectifying the deficiencies attendant the known prior art bladder airbag system.
As has been also noted within the prior related patent application, with a dual bladder airbag system, when the overlapping bladders are inflated for usage, the overlapping portions of the bladders could directly engage each other and may therefore possibly tend to develop some friction therebetween which could possibly adversely affect the structural integrity of the bladders, at least within those portions of the bladders which may possibly frictionally engage each other. Accordingly, in accordance with a further feature of the invention, a slip sheet is interposed between the two inflatable bladders in order to minimize the amount of friction which may possibly develop between the bladders, and to in fact prevent direct engagement or contact between the bladders. As is also disclosed within the noted prior related patent application, however, the slip sheet is not always used in connection with the bladders, or alternatively, is only used depending upon, for example, the size of the particular cargo load rolls or drums. In addition, the slip sheet is not actually attached or secured to the bladders but only loosely interposed therebetween so as to be disposed in a free-floating mode within the airbag container, although its movement may be somewhat limited or restricted as a result of one of the inflation valves of one of the dual bladders passing through a portion of the slip sheet. Consequently, the slip sheet may experience or undergo some unintentional and undesirable movement with respect to the dual bladders whereby the slip sheet may not always be disposed with respect to the dual bladders in order to properly protect the bladders or effectively prevent the direct engagement or contact of the bladders whereby undesirable friction may in fact develop between portions of the bladders.
There is therefore a need, to which the present invention is directed, for a dual bladder airbag system which is not only able to achieve the objectives of the dual bladder airbag system disclosed within the prior related patent application, whereby the problems, drawbacks, and disadvantages of the known prior art are able to be overcome, but in addition, the new and improved dual bladder airbag system comprising the present invention may insure proper protection of the dual bladders of such airbag system at all times so as to assuredly eliminate or prevent the development of any friction, abrasion, or pinching of the bladders during inflation and operation of the same.