Method and apparatus for hard object detection
First Claim
1. Apparatus for detecting the presence of hard objects in a material, said apparatus comprising:
- a feed mechanism including at least one hollow rotatable feed roll for transporting said material along a feed path;
sensor means for sensing impacts of hard objects in said material on said feed mechanism;
mounting means for supporting said sensor means in a stationary position inside said feed roll with an air gap between said sensor means and said feed roll whereby said feed roll ma move relative to said sensor means;
said sensor means comprising means for sensing air-borne sound waves passing through said air gap as a result of said impacts and generating electrical signals in response to said sensed sound waves;
stop means for stopping said feed mechanism; and
,circuit means for applying said electrical signals to said stop means to stop said feed mechanism.
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Accused Products
Abstract
A thin film highly directional audible sound sensor is mounted within a rotatable feed roll of a forage harvester to detect the presence of stones and other hard foreign objects in a crop material being fed past the feed roll to a cutter mechanism. Air-borne sound waves produced by the impact of foreign objects on metal parts of the harvester are detected by the sensor which produces a signal for stopping the crop feed mechanism before the foreign objects reach the cutter mechanism. The sensor is mounted on a stationary support within the rotatable feed roll. Output signals from the sensor control a stop mechanism for the crop feed mechanism via conductors extending through a stationary support shaft for the feed roll, thereby avoiding the need to commutate output signals from the detector.
18 Citations
16 Claims
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1. Apparatus for detecting the presence of hard objects in a material, said apparatus comprising:
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a feed mechanism including at least one hollow rotatable feed roll for transporting said material along a feed path; sensor means for sensing impacts of hard objects in said material on said feed mechanism; mounting means for supporting said sensor means in a stationary position inside said feed roll with an air gap between said sensor means and said feed roll whereby said feed roll ma move relative to said sensor means; said sensor means comprising means for sensing air-borne sound waves passing through said air gap as a result of said impacts and generating electrical signals in response to said sensed sound waves; stop means for stopping said feed mechanism; and
,circuit means for applying said electrical signals to said stop means to stop said feed mechanism. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for detecting the presence of hard objects in a material being transported along a feed path by a feed mechanism including at least one hollow rotatable feed roll, said method comprising:
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mounting a sensor means in a stationary position within the hollow rotatable feed roll and spaced therefrom by an air gap to sense air-borne sound waves traversing said air gap and produced by impact of hard objects in said material on said feed mechanism; generating electrical signals in response to air-borne sound waves sensed by said sensor means; providing a stop means for stopping said feed mechanism; and
,applying said generated electrical signals to said stop means to stop said feed mechanism. - View Dependent Claims (8)
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9. In a forage harvester having a feed mechanism for transporting a crop material along a feed path to a rotating cutterhead, said feed mechanism including at least one hollow rotatable feed roll, apparatus for detecting the presence of hard objects in said crop material, said apparatus comprising:
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acoustic sensor means for sensing air-borne sound waves caused by impacts of hard objects in said crop material on said feed mechanism and generating electrical signals in response to said sensed sound waves; means supporting said acoustic sensor means in a fixed position in the interior of said hollow rotatable feed roll, said support means including acoustic isolator means for isolating said acoustic sensor means from mechanical vibrations induced in said mounting means by operation of said harvester; stop means for stopping said feed mechanism; and
,circuit means for applying said electrical signals to said stop means to thereby stop said feed mechanism when a hard object impacts said feed mechanism. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification