Extension trestle

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An expansion Bock , also Bock expansion called, is a hydraulic powered roof supports , which in coal mining in longwall mining is used. The extension frame was the successor of the extension team . The further development of the extension frame is the shield extension .

Structure and use

The support frame consists of a base frame, four hydraulic rams and a cap . The base frame is formed from merged sole sleepers. The hanging cap is usually closed over a large area in this type of step support. But there are also types with a split cap. The closed cap ensures protection against falling stone and coal from the hanging area . However, trestles do not offer sufficient protection against mountains from the old man . With this type of support structure, waste material can penetrate from the fracture zone into the longwall and thus hinder the regular extraction . Improved designs have a break screen attached to the trestle. This protects the longwall area from debris. So that the support frame can be moved, it has a walking mechanism that is attached to the face conveyor . With this walking mechanism, the support frame on the face conveyor is pulled forward. For the operation in blow-off struts there are specially developed extension blocks for blow-off plants .

Individual evidence

  1. ↑ a b c d e Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining dictionary . 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
  2. ^ Ernst-Ulrich Reuther: Textbook of mining science. First volume, 12th edition, VGE Verlag GmbH, Essen 2010, ISBN 978-3-86797-076-1 , pp. 555-556.
  3. ^ A b c Heinz M. Hiersig (Ed.): VDI-Lexikon Maschinenbau . VDI-Verlag GmbH, Düsseldorf 1995, ISBN 9783540621331 .
  4. ↑ a b c d Heinz M. Hiersig (Ed.): VDI-Lexikon Energietechnik . Springer-Verlag Berlin-Heidelberg GmbH, Berlin 1994, ISBN 3-642-95749-8 .
  5. ↑ P. Migenda, F. Graewe, B.-W. Rätz: Striding support for longwall and striving at great depths . In: Commission of the European Community (ed.): Technical research coal . Research project No. 7220-AD / 133 final report, Luxembourg 1990, p. 10.
  6. ↑ Extension frame, especially for use in blow molding operations . Patent registration of the Eisenhütte Westfalia GmbH trade union, documentation number DE3818725A December 14, 1989, Lünen 1989.

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