Improvements in or relating to Concrete Props and Beams for Supporting the Roofs of Coal Mines and other Mines and for like purposes

115,539. Lewis, E. F., and Lewis, R. J. July 11, 1917. Mine props.-The prop or support comprises two side posts A and a cross-beam D, each made of reinforced concrete. Each post is recessed into the beam in some such manner as is shown at D', D , the joint being also curved from side to side, a...

Ausführliche Beschreibung

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Bibliographische Detailangaben
Hauptverfasser: ELIAS FREDERICK LEWIS, RICHARD JOHN LEWIS
Format: Patent
Sprache:eng
Schlagworte:
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