| 摘要 |
<p>The electrohydraulic circuit for the chain drive of a coal cutting machine, with protection against failure in steep galleries, has a hydrostatic pump (1) for the motor driving the winding drum. In the circuit are pressure limiting valves which protect the circuit against overload and a safety valve to protect the circulating pump. This circuit is connected to two pairs of pressure switches. One pair is adjusted to the upper and lower limiting values of the cable tension for the lowest position, and the other pair is adjusted to the upper and lower limiting values of the cable tension for the highest position. A rectifier valve and a maximum pressure switch are included in the connection between the switch system and the pumping circuit, also a throttling valve.</p> |
