Steering system for self-propelled lawnmower - uses buried cable carrying alternating current for mower magnetic field sensor

摘要

Steering system for self-propelled lawnmower has a conductor cable supplied with alternating current laid in the ground of the lawn in a uniform distribution, so that the magnetic alternating field which results can be sensed by a feeler on the lawnmower, to guide the lawnmower continuously over the whole lawn surface. Pref. the lawnmower automatically stops on meeting an obstacle, and its drive is stopped if the current fails in the steering cable or if no induced signal is sensed. The feeler consists of two feeler coils mounted forward in the lawnmower, on a crossbeam carried by the steering arm, on both sides and symmetrically to the mowers long axis.