Traversing mechanism

A traversing mechanism comprising a guide member and a cam shaft having on its outer surface an endless helical cam groove, said guide member comprising a cam shoe adapted to engage with said cam groove to thereby cause the guide member to reciprocate along the axis of said cam shaft, and further including a cylindrical retaining portion having an axis essentially perpendicular to said cam shaft axis for receiving said cam shoe, said cam shoe comprising a rotatable member rotatably fitted into said cylindrical retaining portion and a separate slidable member fixedly mounted in said rotatable member, said slidable member being formed from a flat piece of hard ceramic material with one end serving as an engaging end portion to engage said cam groove and slide therein, and said rotatable member being cylindrical and having at one end a grooved retaining slot into which the other end of said slidable member is fitted for assembling of both members.