| 摘要 |
In the long wall mining of coal, a sectional pan-line is positioned along the working face of the coal seam parallel with the working face. The pan-line sections joined together have parallel rails along which the mining machine travels. At least one of said rails comprises a continuous gear rack at a height above ground with which a power driven gear wheel on the mining machine meshes for propelling the machine back and forth along the face of the coal. This invention is for a wheeled flat bed dolly having two parallel rails, one along each side, that are of height and width matching the rails of the pan-line. There is a support at one end of each of these rails to which the ends of the rails of the pan-line interfit with a temporary connection holding the dolly and pan-line against separation. That rail on the dolly that joins with the gear rack of the pan-line also comprises a gear rack conforming to and matching gear rack on the pan-line, the arrangement enabling the mining machine moving from the pan-line onto the dolly or from the dolly onto the pan-line under its own power. This dispenses with the hours of labor and hazardous work presently required to effect this transition.
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