Three tree

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Tripod as a sheave frame

A tripod also tripod , Dreifuss , crows feet , or gallows called, is a strong created from three round wood frame, which was used in the Erdbohrtechnik for lifting the drilling equipment. After the Second World War up to the middle of the 20th century, tripods were often used as simple rope sheaves on the small mines operated at that time .

Structure and use

For the construction of a tripod, three shod and hewn round timbers or trunks are required. The length of these woods determines the height of the tripod. It is between four and ten meters. The three woods, which the miner as Rüstbäume called, spit trees or Spitz rafters are made with the log ends either sleepers or sunk directly into the ground. They are set up in such a way that they form roughly the shape of a pyramid. In the foot area, the pieces of wood set up in this way form a triangle. To connect the pieces of wood, two of the pieces of wood are mortised together at the top . The third piece of wood is cut diagonally at the upper end and leaned against these two pieces of wood and connected to them with an iron band and a long screw. In another variant, two arming trees are connected to one another in the upper area with a cross beam. The third arming tree is put at the top between the two other arming trees and connected to it lying on the crossbar. To stiffen the entire construction, the arming trees are connected with crossbars about halfway up. In the upper area of ​​the tripod, a small pulley is placed on crossbars. So that the top of the tripod can also be driven on, rungs are usually attached to one of the arming trees, on which one can climb to the top of the scaffolding if necessary. Tripods were used in drilling operations to a depth of 100 meters.

Individual evidence

  1. a b Gerhard Koetter (Ed.): From seams, tunnels and shafts in the Muttental. 1st edition, Klartext Verlag, Essen 2007, ISBN 978-3-89861-612-6 , p. 28.
  2. a b c d Fritz Heise, Fritz Herbst: Textbook of mining science with special consideration of hard coal mining. First volume, published by Julius Springer, Berlin 1908, pp. 76–77.
  3. ^ A b c Heinrich Veith: German mountain dictionary with evidence. Published by Wilhelm Gottlieb Korn, Breslau 1871.
  4. a b c d e f g Albert Serlo: Guide to mining science. First volume, published by Julius Springer, Berlin 1869, pp. 81–82.
  5. a b c Karl Friedrich Selbmann: From the earth or mountain drill and its use in mining and in agriculture. Bey Friedrich Fleischer, Leipzig and Sorau 1823, pp. 60–62.
  6. a b c August Heinrich Beer: Erdbohrkunde. A section from the exploration and alignment work of general mining science, published by the kk Hof-Buch- und Kunsthandlung FA Credner, Prague 1858, pp. 32–33.