| 摘要 |
<p>In an assembly of mine-roof supports (1 to 8), when a support has completed its advancing operation it sends, to a remote processing unit, an "advance-completed" signal. That signal also identifies the specific support which has advanced. At least two supports of every predetermined number of adjacent supports each has a manual control which, when operated, sends a "manual" signal to the processing unit. The manual signal also identifies the specific support whose manual control has been operated. After a specific support has been advanced and a specific manual control has been operated, the processing unit compares the two identification signals. As a result of that comparison the processing unit will or will not send a signal to initiate advance of the next-to-advance support. <IMAGE></p> |
