| 摘要 |
As is known mineral, e.g. coal, is won from a mineral face with the aid of a winning machine guided for movement along a conveyor composed of individual pans joined end-to-end. The conveyor is advanced towards the face behind the machine by shifting rams linked to the pans. In accordance with the invention, the rams are connected to and disconnected from a supply of pressure fluid in a controlled manner to form a group composed of a predetermined number of rams which are simultaneously charged with pressure fluid and this group progresses along the working behind the machine step-by-step in a sliding fashion within and over larger bank-push groups of rams.
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