| 摘要 |
995,210. Mineral-mining machines. HOUILLERES DU BASSIN DE LORRAINE. Oct. 18, 1963 [Oct. 23, 1962], No. 41181/63. Drawings to Specification. Heading E1F. [Also in Division G4] As a coal cutter advances, pulses are produced which rotate a screw to move a recording stylus along a constantly rotating record drum. As the coal cutter moves backwards or forwards one of two switches is closed and opened by a cam at a frequency depending on the speed of travel. Pulses from either switch actuate a corresponding solenoid-operated pawl to rotate a corresponding one of two ratchet wheels, having oppositely-directed teeth, on the rod of the screw. If the stylus reaches the end of the screw further actuation of the pawl producing movement in the same direction is prevented. |
