Variable sensitivity metal detection system
First Claim
1. In a forage harvester having a metal detector system for detecting tramp metal moving with crop material through a crop feed, and a pair of feed rolls for feeding crop material through said crop feed, at least one of said feed rolls being movable relative to a metal detector in said metal detector system at varying distances therefrom to induce a noise component in the output signal produced by said metal detector, a method of providing a more uniform detection of tramp metal in said crop material, said method comprising sensing displacement of said one feed roll relative to said metal detector, and varying the sensitivity of said metal detector system in accordance with said displacement.
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Accused Products
Abstract
In a forage harvester having a metal detector positioned within a first feed roll and a second feed roll whose displacement from the first feed roll varies with the bulk of crop material passing between the feed rolls, the sensitivity of the metal detector is adjusted according to the displacement of the second feed roll from the metal detector to provide a more uniform detection of tramp metal with varying crop bulk. The sensitivity is increased as the inherent noise component induced in the metal detector output signal by the second feed roll decreases as the second feed roll is displaced from the metal detector by crop bulk.
23 Citations
9 Claims
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1. In a forage harvester having a metal detector system for detecting tramp metal moving with crop material through a crop feed, and a pair of feed rolls for feeding crop material through said crop feed, at least one of said feed rolls being movable relative to a metal detector in said metal detector system at varying distances therefrom to induce a noise component in the output signal produced by said metal detector, a method of providing a more uniform detection of tramp metal in said crop material, said method comprising sensing displacement of said one feed roll relative to said metal detector, and varying the sensitivity of said metal detector system in accordance with said displacement.
- 2. In a forage harvester having a metal detector system for detecting tramp metal moving with crop material through a crop feed, and a pair of feed rolls for feeding crop material through said crop feed, at least one of said feed rolls being movable relative to a metal detector in said metal detector system at varying distances therefrom to induce a noise component in the output signal produced by said metal detector, apparatus for providing a more uniform detection of tramp metal in said crop material, said apparatus comprising sensing means for sensing displacement of said one feed roll relative to said metal detector, and means for varying the sensitivity of said metal detector system in accordance with said displacement.
Specification