Rolling of Equal Hyperbolas
Illustration of the rolling of equal hyperbolas. If two equal hyperbolas are placed so that the distances between their foci O1 and O2, and d and e, are each equal to fg=hk, they will make contact at some point c.
Peter Schwamb, S.B. And Allyne L. Merrill, S.B. Elements of Mechanism (New York, NY: John Wiley & Sons, Inc., 1904)
Courtesy the private collection of Roy Winkelman