Energy absorbing aircraft seat frame structure

Abstract

Improved energy absorbing seat frame structure for an aircraft seat has leg structures which comprise a pair of generally U-shaped front and rear legs which are joined back to back in a generally X-shaped configuration. A curved die member is held in contact with the forward facing concave portion of the front leg by a strap member which surrounds the rear leg. In a crash situation, the front leg can bend about the die member to lower the center of gravity. In a preferred embodiment, strap type clamps on the upper ends of each leg permit the legs to rotate relative to the tubular stretcher members of the seat. The ability of the front legs to be deformed downwardly permits a portion of the excess loading on one front leg to be transferred through the front stretcher member to the other leg which is less heavily loaded. Pin joint connections of the leg assembly to the front and rear track fittings enables the structure to accommodate, and to uniformly transfer, loading to seat tracks which have been deformed vertically. A modified fitting also accommodates twisting deformation of the seat track. The seat can have its front and rear legs positioned closer together than conventional seats for a given 'G' loading, so as to increase passenger leg room behind the seat. Alternatively, for a given front to rear leg spacing distance, the 'G' loading capacity of a particular seat can be significantly increased without increasing the loading on the seat track.