Définition

• Uhlhorn.  The first toggle-joint or knuckle-joint style press, one of the most successful for striking coins, developoed by a German, Diedrich Uhlhorn. Only screw presses were used until Uhlhorn (1764-1837) adapted the unusual action of the toggle-joint to coining.
  By 1813 he had built a working prototype of a coin press based on his toggle joint principle. This allowed coins to be struck at much greater speed than was possible with manual screw presses.He receiving his patent in 1817 and was accepted for use in the Dusseldorf Mint in July 1818 and in Berlin in 1820. By 1827 it could also be found in mints in Utrecht, Vienna and Munich.
  With his cocining presses in use at several European mints, Uhlhorn opened a factory for building coin presses. His youngest son, Johann Heinrich, was his partner in this business, the Werkst?tte f?r M?nzpr?gemaschinen His son died in 1830 and Dietrich ran the business until his death in 1837
              His factory, Uhlhorn & Sohn, continued after his death. Even when it went out of business (about 1880) his presses were being widely copied by mints. The Royal Mint London even built Uhlhorn-style presses after 1950, thus his presses were in use for over 150 years.  See PRESSES AND PRESSROOM PRACTICE.
  References:                                                                                                                       
  E3   {1902-30} Forrer 6: 160-62; illustrated (same as Thonnelier).
  C71  {1988} Cooper p 126-154 (chapters 12, 13, 14); 172-3; 187, 213, 231.
  NE42 {1984} Junge p 263. 
  CH64 {1992} Challis p 522.
  Also Benad-Wagenhoff, Diedrich Uhlhorn und die Moderne M?nztechnik.]

  excerpted with permission from

  An Encyclopedia of Coin and Medal Technology

  For Artists, Makers, Collectors and Curators

  COMPILED AND WRITTEN BY D. WAYNE JOHNSON

  Roger W. Burdette, Editor

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