Patent ID: 8579714

Claim:
A mechanism for space orientating a payload bay with at least three rotational degrees of freedom, the mechanism comprising: an outer frame being equipped with four torque output devices, shafts of the torque output devices coinciding with concentric vertex axes of the outer frame, output shafts of the four torque output devices coinciding with the concentric vertex axes of the outer frame and being pivotally connected with four arc-link assemblies, the four arc-link assemblies being served to transfer the torques from the four torque output devices to an inner frame, each of the arc-link assemblies having an outer arc-link and an inner arc-link, which are jointed mutually with a joint axle, the outer arc-link having its outer end pivoted with each output shaft and a torque output device through an outer axle, while the inner arc-link has its inner end pivoted with a bearing seat onto the inner frame through an inner axle; and an inner frame for collecting the output of the four torque output devices transferred by the four arc-link assemblies so as to collectively reflect the output into the desired motion and posture of the payload bay, the four inner arc-links being pivotally connected to the four bearing seats at the four vertexes of the inner frame; wherein the payload bay is installed in the inner frame, and the four arc-link assemblies serve to perform the three rotational degrees of freedom motion through the four torque output devices; wherein the four vertexes of the outer frame are equally distant from a notional center of an outer tetrahedron; wherein the four outer arc-links have equal radii and the inner arc-links have equal radii; in the assemblies, all the axles of the outer arc-links and the inner arc-links are concentric; wherein the four vertexes of the inner frame are equally distant from the notional center of the inner tetrahedron; wherein the notional center of the inner frame and the notional center of the outer frame must coincide with each other.