Link 1 has spherical half-collars a fitting over ball-shaped head b of link 3. At its other end link 3 has a second ball-shaped head c fitting into spherical half-collars d of link 2. With respect to each other, links 1 and 2 accomplish five turning motions about the three perpendicular axes intersecting at point 0 and about two perpendicular axes intersecting at point 0' .
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