摘要 |
A transmitter is mounted on a cultivator hitched to a tractor or the like for emitting a noninvasive sensor beam generally parallel to and in front of a soil-cultivating implement which tills the soil. Mechanism detects echoes from obstructions in the path of the implement and controls mechanism for retracting the implement so that the implement does not engage the obstructions. When an obstruction has passed, the implement is returned to its working position extending transversely to the direction of movement of the cultivator.
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