Roll-up inflatable beam structure

Abstract

A sandwich beam including in one example first and second spaced walls, a core configured to maintain a predetermined spacing between the walls when the core is filled with pressurized gas and to resist shear when the beam is loaded in bending and a port for filling the core with gas biasing both walls in tension. The tension tends to increase in the second wall and decrease and cause a compression load in the first wall in response to a sufficiently large applied bending load. A compression element is fixed only with respect to the first wall and is configured (a) to support the compression load so that the beam is stronger at a given gas pressure and (b) to flex sufficiently to allow the beam to be rolled up when the gas is emptied from the core via the port.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of and priority to U.S. Provisional Application Ser. No. 60 / 965,670, filed Aug. 21, 2007, which is incorporated herein by reference.FIELD OF THE INVENTION[0002]This subject invention relates to inflatable structures.BACKGROUND OF THE INVENTION[0003]Inflatable structures such as the surfboard discussed in U.S. Published Patent Application No. 2003 / 0153221 (incorporated herein by this reference) are becoming increasingly popular. U.S. Pat. No. 2,743,510 (incorporated herein by this reference) discloses an inflatable structure with top and bottom walls made of fabric and drop stitches securing the top and bottom walls together to hold them in a desired shape when the structure is inflated. See also U.S. Pat. No. 6,066,016 also incorporated herein by this reference.[0004]Such inflatable structures are generally weak in buckling owing to the fact that the top and bottom walls must be sufficiently flexible so that the structure...

AI Technical Summary

Benefits of technology

[0008]It is therefore an object of this invention to provide a stronger inflatable structure.

[0009]It is a further object of this invention to provide such an inflatable structure which better withstands buckling loads.

[0010]It is a further object of this invention to provide such an inflatable structure which better withstands buckling loads without the need to increase the inflation pressure.

Problems solved by technology

Such inflatable structures are generally weak in buckling owing to the fact that the top and bottom walls must be sufficiently flexible so that the structure can be rolled up when deflated for transport and storage.

Adding additional air pressure so the surfboard can sustain greater loads is both difficult in the field and can be dangerous and / or result in severe stress on the components of the inflated surfboard.

While it is common knowledge that an inflatable beam can be stiffened by adding batons (e.g., shock-corded aluminum tubes used on the Feathercraft Gemini kayak), this method is time consuming to assemble and provides only a small increase in strength and stiffness.

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