LINING FOR AREAS OF BRANCHING GALLERIES - DOOR FRAME LINK PROTECTION

摘要

This reinforcement contains a ball joining arched parts (3) with beams (1,2). The main element of the ball is a coupling (4) located in the hole (5) of the side wall (6) of the beam (1,2). The coupling (4) has on the rear side cogs (8,9) and from the front side there is a hole (2) for the mandrel (14) which links it to the arched piece (3). The coupling (4) has a securing element in the form of support (16) covering the lower part of the hole (5) in the beam (1).