| 摘要 |
A mine roof support comprises a base structure, extensible prop means mounted on said base structure and a roof-engaging structure mounted on said prop means. The roof-engaging structure includes a canopy of U-shape or having a U-shaped part and a roof-engaging bar or member positioned or having a part positioned between or partially between the limbs of said U-shaped canopy or U-shaped part thereof. In one preferred embodiment of the invention the canopy is supported on at least one front prop and on at least one rear prop and the roof-engaging bar or member is pivotally connected to the canopy by a pivot having its axis positioned between said front and rear props. |
