separation between the rotating elements returning now to fig3 it will be seen that upper race 71 is in rolling contact with conical rollers 72 which in turn are in rolling contact with lower race 73 a circular lip 72a on the radially outward end of each roller 72 is in rolling point contact with circular flange 73a of lower race 73 these points of rolling contact are continually aligned with the lines of contact between rollers 72 and race 73 there thus being no sliding friction thereat circular lips 72a are also in rolling point contact with circular flange 71a of upper race 71 each roller 72 has a notch 72bwhich rolls over a pin 74 affixed to lower race 73 and over another pin 74 affixed to upper race 71 the upper pin not being shown in the figure upper and lower races 71 and 73 may be identical as shown after assembly of device 70 rollers 72 must be positioned so that their notches will engage pins 74 continuous contact must be maintained between the races and the rollers to prevent their displacement the ratio of the diameter of either race to the diameter of the roller at any point of contact must be an integer to assure engagement of the pins and notches during continuous rotation or additional notches and or pins may be provided in a variation of device 70 pin 74 would be moved onto the circular race surfaces of races 71 and 73 and each.