Apparatus for generating lobular polygonal forms

摘要

Apparatus for generating a lobular polygonal form comprises a first device rotatable about an axis, a second device including a member eccentric to the axis and movable in an orbit thereabout, and a third device responsive to said combined movement of the first and second device for tracing a lobular polygonal form (1) which has an odd number of sides capable of maintaining approximate tangency with two parallel planes upon rotation of said form or (2) which has an even number of sides capable upon rotation of the form of maintaining approximate tangency with three circles of equal diameter and having equidistant centers. The generated lobular form may be traced by a metal-working tool that forms a die cavity in a workpiece. A novel lobular screw blank may be formed in the die cavity.