bele oolumfl abattageminier site for powered support

摘要

A mine roof support bar assembly composed of two bars pivotably interconnected at adjacent ends with a hinge pin extending through lugs formed at these ends of the bars. The axis of the pin lies above the longitudinal axes of the bars when the latter are arranged in a co-linear horizontal position. The adjacent ends of the bars have interengageable extensions disposed beneath the lugs with a cavity formed between the extensions and the lugs. The extensions prevent the bars from pivoting downwards away from the horizontal position while the cavity can receive an insert body which is used to secure the bars in an upwardly inclined position.