Cutting sharpness detection device

Patent metadata

Field	Value
Publication number	US-11566883-B2
Application number	US-202016815221-A
Country	US
Kind code	B2
Filing date	Mar 11, 2020
Priority date	May 16, 2019
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

A detection arrangement for detecting a wear status of a chopping knife arrangement of a chopping device provided for processing a product flow, wherein the chopping device has a revolving chopping drum receiving the chopping knife arrangement and at least one shear bar which cooperates with the chopping knives, with a sensor arrangement which has a magnetic exciter arrangement and a flux conducting device magnetically coupled thereto. The sensor arrangement provides a pole arrangement which forms at least one magnetic pole with a pole surface for conducting magnetic flux, wherein at least a portion of the chopping knife passes the pole arrangement during a rotation of the chopping drum. A voltage induced when a chopping knife arrangement passes the sensor arrangement forms the measured magnetic value, which is used by the evaluation unit to determine the state of wear of the chopping knife arrangement.

First claim

What is claimed is:

1. A detection arrangement for detecting a wear status of a chopping knife arrangement of a chopping device provided for processing a product flow, wherein the chopping device has a revolving chopping drum receiving the chopping knife arrangement and at least one shear bar which cooperates with chopping knives of the chopping knife arrangement, wherein the detection arrangement comprises:
at least one sensor arrangement which has a magnetic exciter arrangement and a flux conducting device magnetically coupled thereto, wherein the sensor arrangement provides a pole arrangement which forms at least one magnetic pole with a pole surface for conducting magnetic flux, wherein the sensor arrangement is configured such that at least a portion of the chopping knife passes the pole arrangement during a rotation of the chopping drum, the chopping knife passing the pole arrangement forms an air gap arrangement with at least one air gap with respect to the pole arrangement, and at least one magnetic circuit excited by the exciter arrangement is accordingly closed via the respective chopping knife,
a measuring arrangement, and an evaluating unit, wherein the measuring arrangement is configured to detect at least one measured magnetic value pertaining to the magnetic flux in at least one magnetic circuit excited by the exciter arrangement, wherein voltage induced when a chopping knife arrangement passes the sensor arrangement forms the measured magnetic value, and
wherein the evaluating unit is configured to determine the wear status of the respective chopping knife from the at least one detected measured magnetic value by
determining the induced voltage and recording the induced voltage as a voltage signal,
resolving the voltage signal into its frequency components by means of frequency analysis,
separating the frequency components into frequency components of a fundamental oscillation and into frequency components of a superposed oscillation which cause signal distortion,
inverse-transforming the separated frequency components of the superposed oscillation which cause a signal distortion in a time domain, and
deriving a measurement for the wear status or cutting sharpness of the chopping knife from the inverse-transformed frequency components of the superposed oscillation.

2. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 1 , wherein the frequency components comprise the amplitude and the phase of the respective voltage signal.

3. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 1 , wherein the frequency analysis of the voltage signal is carried out by means of Fourier analysis.

4. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 1 , wherein a plurality of induction sensors are associated with each sensor arrangement, and each induction sensor generates a voltage signal, wherein each of the generated voltage signals is analyzed separately, and wherein a plurality of voltage signals, or all of the voltage signals, of a detected chopping knife are combined to form one or more voltage signals prior to an analysis.

5. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 1 , wherein the respective voltage signal is classified into frequency components of a fundamental oscillation and frequency components of a superposed oscillation which cause signal distortions, and wherein the frequency components representing the fundamental oscillation are not taken into account in the derivation of the wear status or of the cutting sharpness of the respective chopping knife.

6. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 5 , wherein an amplitude of the respective voltage signal of the frequency components causing a signal distortion forms a measurement for assessing the wear status and/or cutting sharpness of the respective chopping knife.

7. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 1 , wherein the at least one sensor arrangement is configured to be positioned at a circumference of the chopping drum such that every chopping knife of the chopping drum is detected by means of the at least one sensor arrangement.

8. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 7 , wherein right-hand-side and left-hand-side chopping knife arrangements are associated with the chopping drum, and at least one sensor arrangement is associated with each of said chopping knife arrangements.

9. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 1 , wherein a reference value indicating a sharp knife is stored in the evaluating unit or in another data processing device, and wherein when the wear status of a chopping knife falls below this reference value, the detection arrangement is configured to generate a grinding signal, and wherein the reference value forms an amplitude of a voltage signal indicating a sharp knife.

10. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 9 , wherein the generation of a grinding signal includes the generation of an informatory signal that comprises a visualization of that chopping knife that falls below the reference value.

11. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 9 , wherein the generation of a grinding signal further includes a triggering of a grinding process.

12. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 1 , wherein the assessment of the cutting sharpness or wear status is effected by means of evaluation criteria selected from the group consisting of grinding surface length of the respective chopping knife, roundness of the chopping knife tip, general knife wear, camber of the chopping knife and relative distance of the shear bar from the chopping knife.

13. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 12 , wherein the reference value is an amplitude of a voltage signal indicating roundness of the chopping knife tip.

14. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 12 , wherein the reference value is an oscillation period of a voltage indicating grinding surface length of the respective chopping knife.

15. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 12 , wherein the reference value comprises an amplitude and an oscillation period of a voltage signal indicating general knife wear.

16. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 12 , wherein the reference value is an amplitude of a voltage signal indicating camber of the chopping knife or relative distance of the shear bar from the chopping knife.

17. The detection arrangement for detecting a wear status of a chopping knife arrangement according to claim 12 , wherein a reference value is stored in the evaluating unit and/or some other data processing device for every evaluation criterion, and ii wherein the detection arrangement is configured to generate a grinding signal or a knife change signal when the wear status falls below this reference value,
wherein the refer

Assignees

• Claas Selbstfahrende Erntemaschinen Gmbh

Inventors

• Heitmann Christoph
• Neitemeier Dennis
• Brune Markus
• Huster Jochen
• Fischer Frédéric
• Stremlau Bjoern

Classifications

• G01B7/023

  for measuring distance between sensor and object (G01B7/082 and G01B7/102 take precedence) · CPC title

• A01D41/127

  Control or measuring arrangements specially adapted for combines · CPC title

• B60W50/0098

  Details of control systems ensuring comfort, safety or stability not otherwise provided for · CPC title

• B60W50/085

  Changing the parameters of the control units, e.g. changing limit values, working points by control input · CPC title

• G01B7/293 Primary

  for measuring radius of curvature · CPC title