Device for recognizing ferromagnetic foreign bodies, in particular in respect of harvesting machines

Abstract

In a device for recognizing ferromagnetic foreign bodies, for protecting the working members of a harvesting machine, having a magnetic field generating device (9), the lines of flux of which run transversely to the direction of transport, and having assigned pick-up coils (15; 16; 17), it is intended to improve the recognition range across the entire width of the feed system, whilst keeping costs low. At the same time, it is intended better to suppress disturbance signals. For this purpose, the magnetic field generating device (9) comprises an odd number of magnetic poles (12; 13; 14), the two outer magnetic poles (13; 14) possessing the same polarity. At least every second magnetic pole (12) is enclosed by a pick-up coil (15). Expediently, three magnetic poles (12; 13; 14) are present, which are all enclosed by a pick-up coil (15; 16; 17) each. The pick-up coils (15; 16; 17) are connected up such that the induced voltages are added together.

Dependencies are inferred from the claim text.