| 摘要 |
The invention refers to a trestle (1) being displaceable on caterpillars (2) and having an approximately rectangular cross section and serving the purpose of supporting the roof in underground cavities, in particular serving the purpose of securing the excavating edge when recovering pillars (19) in coal mining, the trestle comprising a cap (4) being supported against a base frame (3) by hydraulically expandable props (5) extending approximately vertically relative to stratification. The trestle (1) has, related to the travelling direction of its floor chassis (2), at its both sides supporting plates being adjustable in outward direction and/or horizontal driveable caterpillar chassis being adjustable in outward direction. The supporting plates (22, 23) and/or the lateral caterpillar chassis (20, 21) are adjusted against the frame of the trestle by means of hydraulic or pneumatic pistons and cylinders and are adjustable in outward direction. Beside the cap (4), there can be arranged an optionally driveable caterpillar chassis (26) being adjustable in direction to the roof and extending in parallel relation to the floor chassis or the plurality of such chassis (2). |
