Abstract: A segmented rotatable beam provides a spar or rib in an aircraft wing. The rotatable beam has a variable stiffness dependent upon the radial orientation of the rotatable beam about a longitudinal axis of the beam. The segmented rotatable beam comprises a plurality of tubular segments that are pivotly interconnected by connecting beam links that are rotatably mounted in bearings disposed along the longitudinal axis of the beam.

Abstract: Sign standard comprising two oppositely formed front legs interconnected at their upper ends with a rearwardly disposable third leg through the use of an arcuate joiner means. Each of the two front legs includes a minor upper section which is laterally, angularly disposed with respect to a major lower section. The arcuate joiner means is fixedly attached to the upper end portion of the third leg from which leg said joiner means extend laterally in opposite directions and extend through transverse openings provided in the upper portions of the two front legs. The two front legs and the arcuate joiner means cooperate together to permit the sign standard to assume an open position wherein the lower ends of all three legs are spaced apart relative to each other and to assume a closed position wherein the three legs are in closely adjacent, aligned relationship. Furthermore, means are provided for supporting a diamond shaped sign mounted on the two front legs.

Abstract: Cleaning apparatus usable to clean those portions of a tunnel wall or the like which are located behind railing means typically placed along a walkway beside the wall, such as in a freeway tunnel. A guidance carriage engages the railing and is movable therealong. A support carriage, which can be moved along the walkway, carries a plurality of motor driven circular brushes for cleaning these wall portions. Between the guidance carriage and the support carriage are located linear fluid motors urging the carriages in laterally opposite directions, the support carriage in turn urging the brushes into contact with the wall, and the guidance carriage being urged by said motors against the railing which provides horizontal support for the guidance carriage. The railing also provides vertical support for the guidance carriage while the walkway provides vertical support for the support carriage.