Abstract: A universal joint boom assembly comprising two boom segments having paired eared ends connected end to end by means of a universal joint with one of its set of ears parallel to an X axis and the other set of ears parallel to a Y axis which is perpendicular to the X axis. An offset X axis hydraulic assembly and an offset Y axis hydraulic assembly interconnects the boom segments to cause pivoting of the boom universal joint so as to lean a boom segment in the direction of the X and Y axes respectively.

Abstract: A high lift scissors jack has three sets of scissor members. Each set is joined to the adjacent sets at the corners using connectors which maintain the base and the platform parallel as the structure extends and retracts. The connectors have angularly spaced pivots and the pivots have shoulders which provide lateral support to the ends of the lever arms. The scissor sets are joined to a support base and a platform by similar transition assemblies. The transition assemblies each include a pivoted strut for each set of scissor members. The strut has its base pivotally mounted on the support base or platform and its opposite vertex connected to the end of the scissor set. Extension and retraction are performed by rotating the support base struts about their base pivots.

Abstract: A helicopter rotor having retractable blades each having a three dimensional truss including flexible cables which connect a blade member with a pitch member directly secured to a rotor hub, the cables providing for retraction of the blade member to a storage position and permitting the blade member to be adjustably extended to operative positions. With the rotor rotating normally, the resultant centrifugal force acting on the blade and more particularly the blade member, retains the cables under sufficient tension to form an operationally rigid truss which transmits the rotational force of the rotor to the blade member and also adjusts the pitch of the blade member responsive to operation of the pitch member. Two pairs of cables are provided, inner ends of each pair being spaced apart and retained by the pitch member, opposite ends of each pair being secured, one to each of opposite ends of a rigid rod transverse to the blade member and extending outwardly in opposite directions from the blade member.