Mine gallery support structure - uses channel frames with yielding joints, incorporating support shoes located by cross straps

摘要

The mine gallery strengthening system uses supporting arches made from channel sections with portions against the sides and roof, overlapping at their ends and secured by joints, as in the main patent. These joints are held in tension by locking members which can allow the joint to give under pressure in the event of rock movement. Each joint uses a support shoe which fits into the open mouth of the channel, and projects upwards. This shoe has a tongue (7) at the rear which locates against a stop bar (11) welded across the beaded edges (8, 9) of the channel. At the front is a hooked part (6) which fits under another stop bar (12) which is welded inside the channel nearly flush with the top.