Curved air beam

#The present invention relates to braiding techniques in general and, more particularly, to an inflatable, pre-shaped, braided structure with high fabric integrity.

#An inflatable tubular beam, also known as an air beam, is a structural support element having a pre-shaped structure, e.g., a cylindrical tube, of flexible material which is inflated to develop its rigidity. Air beams are particularly useful in situations where light weight and/or compact storage capability of the uninflated element are desired.

#Inflated air beams can take various shapes and forms. Arched air beams are used, inter alia, in rapidly deployable shelters. Due to the light weight and compactness of the inflatable beams, such shelters are more conveniently transported, more quickly erected, and require less labor than conventional rigid structures.

#The present invention will be better understood from the following detailed description of a preferred embodiment of the invention taken in conjunction with the following drawings in which:

#FIG. 1 is a schematic, cross-sectional, illustration of an air beam in accordance with an embodiment of the present invention;

#FIG. 2 is a schematic illustration of part of a take-up device including conical rollers used to form curved braided structures in accordance with an embodiment of the present invention; and

#Reference is now made to FIG. 1 which schematically illustrates a cross-sectional view of an air beam 10 having a braided sleeve 12, e.g. a triaxial braided sleeve, surrounding an air bladder 14. Braided sleeve 12 includes axial fibers 16 (also referred to as “axials 16”), which are preferably equally or regularly spaced along the circumference of sleeve 12, and bias fibers as are known in the art. Such triaxial braided sleeves, having equally or regularly spaced axials, are well-known in the art of braiding.

#Air bladder 14 may be replaced by a pre-formed elastomeric liner, or the braid fibers may be impregnated with an elastomeric solution that forms a gas barrier after curing, as described in U.S. Pat. No. 5,421,128, the entire disclosure of which is incorporated herein by reference. Additionally, the braid fibers may be impregnated with a solution that forms a hard outer surface after curing, as is known in the art.

#A gas barrier may be provided to the air beam fabric by continuously feeding a plastic sleeve made of poly-tubing material, for example the poly-tubing material (product number 089984) available from Consolidated Plastics, Twinsburg, Ohio, into the braid while the braid is being formed. The diameter of the sleeve should be substantially the same as or slightly larger than the inflated inside diameter of the braid. Adhesive may be applied to the outer surface of the plastic sleeve, using coating processes as are known in the art, prior to insertion of the sleeve into the braid, however, this step may not be necessary. The plastic sleeve may be brought into full contact with the inner surface of the braid by maintaining a low inflation pressure air pocket in the sleeve between the source of the sleeve and nip puller which forms the braid. This technique is known in the art. Alternatively, the braid and air bladder assembly may be inflated after formation and maintained inflated until the adhesive is adequately cured.