Johann Friedrich Trefz

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Calcorota (crank wheel) by Johann Friedrich Trefz (1869)

Johann Friedrich Trefz (born July 30, 1832 in Ölbronn ; † 1885 in Arica (Chile) ) was a German gymnastics teacher and designer of the rear-wheel drive pedal crank bicycle.

Trefz moved to Stuttgart in 1865 and founded the first private gym for girls in 1868. He gave girls “lessons in Vélocipède driving” on bicycles he obtained from France. The authorities found the "first German girls' gym" to be out of date and soon banned classes. Trefz then went back to the regular school service (in Munich?) And taught science and new philology. In 1873, according to the church family register, he "escaped" from Schwäbisch-Gmünd, probably leaving his family behind. According to his grandson Dr. Fritz Trefz traveled to South America in 1885 on behalf of a Dutch company that was looking for mineral resources there.

In contrast to Thomas McCall's oscillating drive , Trefz used pedal cranks on his bike, which he constructed in 1869, which powered the rear wheel via a linkage. On November 30, 1869, Trefz applied for a patent from the Württemberg central office for trade and commerce for a “new way of moving the Velocipede”, which he called “Calcorota”. The request was granted. On January 24, 1871, however, Trefz had to have his patent canceled for unknown reasons. It is uncertain whether Trefz ever made copies. What is certain is that the Müller & Hag company founded the “First German Velocipède Factory” in Stuttgart.

literature

  • Franz Maria Feldhaus : The technology. A lexicon of prehistoric times, historical times and primitive peoples . Engelmann, Leipzig and Berlin 1914.
  • Wolfgang Gronen, Walter Lemke: History of cycling. Fuchs-Druck und Verlag, Hausham 1987.
  • Max JB Rauck, Gerd Volke, Felix R. Paturi: By bike through two centuries. The bicycle and its history. 4th edition. AT Verlag, Aarau u. a. 1988, ISBN 3-85502-038-8 .
  • Hans-Erhard Lessing: Around Michaux: myths and realities - Towards a new chart of early bicycle history. Proceedings of the 2nd International Conference for Cycle History (ICHC), St. Etienne 1993, pp. 21-29

Individual evidence

  1. ↑ Wolfgang Gronen, Walter Lemke, p. 53.
  2. ↑ stadtmuseum-stuttgart.de In the footsteps of ... (accessed on July 28, 2017)
  3. ↑ Advertisement (accessed on July 28, 2017)
  4. ↑ Rauck, p. 34.
  5. ↑ a b c Max JB Rauck, p. 35.
  6. ↑ Dr. Fritz Trefz, letter of September 26, 1948 to Sigfrid von Weiher
  7. ^ Franz Maria Feldhaus: Die Technik , p. 274.
personal data
SURNAME Trefz, Johann Friedrich
BRIEF DESCRIPTION German inventor
DATE OF BIRTH July 30, 1832
PLACE OF BIRTH Ölbronn
DATE OF DEATH 19th century or 20th century
Place of death unsure: Munich