Disposable pit-prop for filling with hardening material - has gear-driven screwed bar thrusting inner and outer tubes apart and actuated from outside

摘要

The prop is particularly for use at the junction between a mine tunnel and gallery, its telescoping tubes being thrust apart and clamped between the roof and floor, after which a core of hardening material holds them in place. Dewatering and/or vent drillings are included. Plates (12, 16) spaced apart are mounted in the inner and outer tubes (2, 3), and are coupled by a screwed bar (15) turning in the plate of the outer tube. A crown wheel (18) with central bush (19) and outer gear ring (23) rotates on the bar and the outer tube plate, and meshes with a pinion (25) driven from the outside. USE/ADVANTAGE - Pit prop can be inserted with great force before filling with the hardening material.