Patent ID: 7506847

Claim:
A machine comprising elongate struts forming a hexapod structure that can be driven through machine nodes to vary the effective strut length, and wherein at least two struts share a bifurcated drive sphere, said hexapod structure comprising six elongate struts with a sub-frame and a platform movable relative thereto and six nodes, three of said nodes connecting alternate strut pair ends to the platform by multi-axis couplings and three of said machine nodes defined in said sub-frame comprising bifurcated drive spheres, each said bifurcated drive sphere being retained within a complementary socket mounted on said sub-frame, each said bifurcated drive sphere retaining a pair of adjacent strut pairs such that adjacent struts of said pair can pass through said retained bifurcated drive sphere and cross over each other within said retained bifurcated drive sphere with pivotal movement about a common axis, wherein said bifurcated drive spheres each comprise two hemispheres, one for each strut passing through the respective bifurcated drive sphere, the two hemispheres being spherically arranged with respect to each other so as to be pivotable relative to each other about a common axis, and the spherically arranged hemispheres being retained in said complementary sockets providing for multi-axis movement thereof, and wherein each of said struts has two ends and the retained bifurcated drive sphere is located on and between said two ends.