Double telescopic mine support ball joint - has ball part with collar and flanged carrier, both secured by rings

摘要

The double telescopic mine support has a roof member attached by a spherical joint. The roof cap is mounted on the underside of the roof support plate with a ring inside which fits a flange. A groove around the inside of the ring holds a resilient ring which retains the flange. Attached to the flange is a stem which supports the ball joint member. This rests on a curve seating at the top of a tube forming part of the telescopic support. The ball part is retained by a ring which is held inside the open top of this tube by another resilient ring.