element 6 provides said sliding contact region s therefore the same effects as those described above can be obtained by positioning the center of curvature o of the spherical outer peripheral surface 3 b of the ring 3 to coincide with the sliding contact region s fig4 and 5 show the present invention applied to joints shown in fig2 and 21 in these joints rolling elements for example needle rollers 6 are disposed on the inner periphery of the outer ring 3 and an inner ring 7 is disposed between the rolling elements 6 and the leg shaft 5 thus the inner ring 7 and the rolling elements 6 are prevented from moving relative to the outer ring 3 in the leg shaft direction in fig4 the movement of the inner ring 7 relative to the outer ring 3 in the leg shaft direction is prevented by contacting the opposite ends of the inner ring 7 with the track groove 2 while in fig5 the inner ring 7 and the rolling elements 6 are prevented from moving relative to the outer ring 3 in the leg shaft direction by integrally engaging their opposite ends with the outer ring 3 through locking members 8 in either construction.