Improvements in and relating to hollow-section (hexagonal) inner pit prop member

摘要

813,848. Pitprops. GUTEHOFFNUNGSHUTTE STERKRADE, A. G. April 23, 1956 [June 27, 1955], No. 12320/56. Class 20(2) The inner member of a pit prop comprises a hollow hexagonal sectioned member having three alternate sides 1 which are internally of trough shape and adapted to provide pressure faces on their outer surfaces for the gripping forces of the clamp, the three intermediate sides 2 being externally of trough shape. The section may be integral as in Fig. 1 or may be formed from two longitudinal members I, II welded together at 4 as shown in Fig. 2.