Patent ID: 8172179

Claim:
An aircraft wing box, wherein the wing box comprises a pair of half ribs joined to form a rib extending from an upper wing skin to a lower wing skin, each half rib comprises a base and a plurality of projections that extend away from the base, the projections defining a series of troughs and peaks, respective projections of one half rib overlap with respective projections of the other half rib thereby defining overlapping portions, the half ribs being joined in the regions of the overlapping portions, there is at least one projection shaped such that the separation, measured in a direction parallel to the height of the rib, between the peak defined by the projection and the adjacent trough is greater than half the height of the half rib in the region of the projection, the half ribs are so arranged that a void is defined in the space between two adjacent projections and a trough on one half rib and the opposite two adjacent projections and one trough on the other half rib, and the void has a height and a width, the height being the maximum separation of the troughs defining the void, measured in a direction parallel to the height of the rib, the width being the maximum separation of the projections defining the void, measured in a direction perpendicular to the height of the void, such that the height of the void is greater than the width of the void.