Edward Hebern of California designed several machines to encipher and decipher typed messages. They used one of the most important twentieth century developments in cipher machines, the rotor. Rotary cipher machines were introduced in the 1920s and 1930s for commercial purposes by several people in several countries.
These two rotors are of Hebern’s design. Each has a metal ring with spokes attached to central hole, between two bakelite rings. Twenty-six short metal strips pass through each rotor. The strips are screwed down on one side of the rotor. On the other side, they are held down with nuts (one rotor has no nuts). Both sides of each rotor have twenty-six round metal contacts, outside the metal strips. A metal band goes around the outside of each rotor, with the letters from A to Y. Between the letters are square openings in the rings. One rotor is numbered “3” on the ring, the other “4”. Both rotors have a mark on one spoke that reads: HEBERN (/) ELECTRIC (/) CODE. They are also marked with various patent dates and numbers. The latest date reads: SEPT. 30, 1924.
Compare the rotor on cipher machine prototype 1991.0190.04.
Reference:
E.H. Hebern, “Electric Coding Machine,” U.S. Patent 1,510,441, September 30, 1924.
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