BE1029616B1 - Arrangement for detecting the sharpness and/or the distance between knives of a chopper drum of a forage harvester and their rotational position and/or speed - Google Patents

Abstract

An arrangement for detecting the sharpness and/or the distance between knives (40) of a chopper drum (22) of a forage harvester (10), a reference body (54) being arranged on the chopper drum (22) between two knives (40) following one another in the circumferential direction which causes a detectable signal from the sensor (42) when passing the sensor (42), and the evaluation device (50) is configured to identify the signal produced when the reference body (54) passes the sensor (42) and to determine a Use value with regard to the rotational position and / or speed of the chopper drum (22).

Description

1 BE2022/0032

Arrangement for detecting the sharpness and / or the distance from

Knives of a chopper drum of a forage harvester and their

rotary position and/or speed

The invention relates to an arrangement for detecting the

Sharpness and / or the distance of knives of a chopper drum of a forage harvester, comprising: a rotatably and drivably mounted chopper drum, to whose

circumference a number of knives are distributed; a sensor configured to interact with the knives by sensing through the tip of a passing

changes in a magnetic field caused by the knife; and an evaluation device configured based on a

Signal of the sensor an initial value in terms of the sharpness of the

provide knife and / or the distance of the knife from the sensor.

State of the art

Forage harvesters are used to harvest whole plants or their parts, which are harvested in operation by means of a header

Field recorded, compressed by pre-compression rollers and supplied to a chopper drum, the knives distributed around the circumference and, if necessary, in the axial direction, the plants in the

Cut together with a shearbar.

Then the cut plants or parts are optionally fed to a post-crushing device and through a

Promoted after-acceleration device in a spout that overloads them on a transport vehicle. The crushed plants are usually used as animal feed or for biogas production.

2 BE2022/0032

Although the knives usually come with a the actual

Coating of a hard material such as tungsten carbide that forms the cutting edge gradually dulls during the harvesting process, so that a grinding process has to be carried out from time to time. To help you choose the right one

Time for a grinding process and / or the associated

Grinding times not dependent on the operator's assessment of the sharpness of the knives are a number of

Sensors have been proposed that are able to detect the sharpness (radius of the cutting edge) and also the distance between the knives and the shearbar, to automatically or after

Operator input to cause a grinding operation and / or an adjustment of the shearbar.

Such sensors are based in particular on inductive

Principles (cf. DE 10 2011 005 317 A1 or DE 10 2014 218 408 A1) and record the passing tips of the knives

Changes in a static magnetic field. These sensors can be fitted with a single (distributed around the circumference of the cutterhead)

row of knives or overlapping with two adjacent rows or be moved across the width of the cutterhead. In addition, these sensors are also able to detect individual knives that are blunter than other knives or a different one

Distance to shearbar than other knives.

The operator can thus be given an indication via an operator interface if individual knives need to be resharpened, replaced or adjusted. However, there is this

Problem, the position of each knife in the circumferential direction

identify the cutterhead and indicate this to the operator so that he does not have to go through all the knives in one or more rows to find the knife in question.

In the prior art, the assignment takes place

Measured values of the sensor for the respective knife (in the case of a forage harvester with a contact sensor for recording the sharpness of the knife) based on

3 BE2022/0032 a measurement of the rotation angle of the cutterhead (EP 2 527 087

A1), while DE 10 2019 112 968 A1 and DE 10 2019 125 624 A1 record and display measured values of the respective

Describe knives, but do not show how the allocation should take place.

A detection of the rotation angle of the chopper drum would not only be useful for identifying individual knives, but also for recognizing the number of knives distributed around the circumference of the chopper drum, since for this not only the number of individual knives is required

Knives assignable, detected with a sensor pulses, but also the associated speed required (see FIG. DE 10 2009 046 821 A1 with a detection of passing knives in a

shearbar induced mechanical vibrations). The same applies to regulating the feed roller speed in order to maintain a desired cutting length, for which purpose the speed of the chopper drum is recorded directly (DE 196 32 977 A1) or indirectly (DE 102 45 885 A1).

Task

In order to enable the measured values of the sharpness sensor to be assigned to individual knives, a sensor is required to record the absolute angle of rotation of the chopper drum, because a pure speed sensor, as is the case in DE 10 2009 046 821 A1, DE 196 32 977 A1 and DE 102 45 885 A1, which only gives a relative value, is not sufficient for this. A separate

However, the angle sensor, as mentioned in EP 2 527 087 A1, requires more effort because it is in the immediate vicinity of the

To attach the cutterhead, i.e. in a place where only a little

Space is available and at which it can be damaged by the harvested crop and juices escaping from it, and is to be connected by cable to an evaluation device. Even if one

Angle of rotation or speed sensor is present, it can fail, which means that the forage harvester can no longer be used and is down until repairs are made.

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The problem on which the invention is based is seen in avoiding or at least reducing the said problems.

Solution

This problem is solved according to the invention by the teaching of claim 1, wherein in the further claims

Features are listed that further develop the solution in an advantageous manner.

An arrangement for detecting the sharpness and/or the

Distance from knives of a chopper drum of a forage harvester comprises a rotatably and drivably mounted chopper drum around the circumference of which a number of knives are distributed; a sensor configured to interact with the knives by sensing changes in a magnetic field caused by the tip of a passing knife; and an evaluation device that is configured to use a signal from the sensor to provide an initial value with regard to the sharpness of the knives and/or the distance between the knives and the sensor. This output value can be used in a manner known per se to control an operator interface and/or to automatically activate a grinding device and/or a

serve shearbar adjustment routine. On the chopper drum, between two knives that follow one another in the circumferential direction

Arranged reference body that causes a detectable signal from the sensor when passing the sensor. The

Evaluation device is configured, which when passing the

Identify reference body on the sensor resulting signal and to determine a value with respect to the rotational position and / or

speed of the chopper drum.

In other words, the sensor not only serves to

Sharpness of the knives and/or their distance from the sensor (or other reference point that is a known distance from the

sensor is located, e.g. the edge of a shearbar facing the chopper drum), but also to measure the

Speed and/or rotational position (angle of rotation in an absolute

coordinate system) of the cutterhead. For this purpose, at least one reference body is attached to the chopper drum, specifically in the sensitive area of the sensor between two knives that follow one another in the circumferential direction. The reference body is through the

Sensor detectable, i.e. made of a suitable - in particular ferromagnetic - material and produced when it is

passes the sensor, a signal in the sensor analogous to the knives. The

Amplitude of the signal generated by the reference body is in the

usually be smaller than the signal produced by a knife and that

The signal will also include a different, in particular longer, time period, but it can be recognized by the evaluation device.

The latter is thus set up, based on the passing of the

To detect the reference body generated in the sensor signal and based on a value in terms of speed and / or

To generate the angle of rotation of the cutterhead. In this way, the disadvantages mentioned are avoided and a separate sensor for detecting the speed and/or the

angle of rotation of the cutterhead.

The evaluation device can be configured based on the identified value for the rotational position of the

to assign the output value to individual knives on the chopper drum.

For this purpose, the evaluation device can use the rotational position and the initial value to display a display assigned to the individual knives with regard to the sharpness and/or distance from the sensor and/or information for an operator derived from this display value on a

Provide operator interface. The operator can thus be alerted, for example, to replace a blade that is significantly blunter than the other blades, or if its tip is located significantly further out or in than the

Tips of the other knives to adjust the knife. Here, a clear identification of the knife is possible, e.g. using the

Position of the knife in (or against) the direction of rotation, counted from

6 BE2022/0032

reference body. The operator no longer has to spend a long time looking for which knife to service, but finds it quickly and easily. Also, the identified speed of the

cutterhead displayed on the operator interface.

Furthermore, the evaluation device can be configured to use the value of the identified speed and the signal from the sensor to identify the number of knives distributed around the circumference of the chopper drum. Based on the identified number of knives, the evaluation device can configure the display, i.e. display measured values with regard to sharpness and/or distance for exactly the number of knives that are also present according to the measurement. The evaluation device can also use the value of the speed and the identified number of knives

Supply cutting length control and from the

Evaluation device determined speed of the chopper drum as a single speed sensor or, if necessary, as a fallback sensor (analogous to the procedure according to DE 102 45 885 A1) in the event of a

failure of another speed sensor for detecting the speed of the chopper drum to control the cutting length control.

The sensor can in a conventional manner as an inductive

Be executed sensor and comprise an electro- or permanent magnet for generating a static magnetic field and a magnetic field influenced by the passing cutting edges of the knife and the reference body arranged magnetic field sensor, which outputs a signal supplied to the evaluation device. The

Sensor can be associated with one or more rows of knives.

example

In the drawings, an embodiment of the invention described in more detail below is shown. It shows:

Fig. 1: a forage harvester in side view and in schematic

representation, and

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Fig. 2: a perspective view of the chopping drum

Forage harvester with an arrangement for detecting the sharpness and/or the distance of knives.

A self-propelled forage harvester shown in FIG. 1 is built upon a frame 12 which is supported by front and rear wheels 14 and 16. As shown in FIG. The operation of

Forage harvester 10 is carried out from a driver's cab 18 from which a crop pick-up device 20 in the form of a pick-up can be seen 10 . Goods picked up from the ground by means of the crop picking-up device 20 , e.g. B. grass or the like, one with

Blades 40 occupied chopping drum 22 supplied, which is in

Cooperation with a shearbar 38 chops into small pieces and a conveyor 24 gives it up. The estate leaves the harvesting machine 10 to a trailer traveling alongside via a position-adjustable chute 26. Between the

Chopping drum 22 and the conveyor 24 is one

Post-crushing device 28 for striking grains contained in the crop for the corn harvest, through which the material to be conveyed is fed tangentially to the conveyor device 24 . Between the

Crop pickup device 20 and the chopper drum 22 will do that

Transported well by lower feed rolls 30,32 and upper feed rolls 34,36. The knife 40 can by means of a

Grinding device 58 are sharpened.

Figure 2 shows a perspective view of

Chopping drum 22. It comprises a shaft 44 rotatably supported in the frame 12, on which are mounted support discs 46 around the circumference of which the knives 40 are distributed. The knives 40 are on

Screwed knife holders 48, as shown here, on the

Support discs 46 are screwed. However, the blade holders 48 could also be welded onto a separate drum casing (not shown) in a manner known per se. It can be seen that twelve knives 40 each in a single row around the circumference of the

Chopping drum 22 are distributed, and that the chopping drum 22 includes a total of four rows of twelve knives 40 each. The

8 BE2022/0032

Knife 40 adjacent rows are offset from each other in the circumferential direction, so that they each successively with the

counter blade 38 cooperate. In Figure 2, the cutting edges of the knives 40 are oriented axially, resulting in a chopping cut of the

Harvested crop in cooperation with the shearbar 38, although the cutting edges of the knives 40 could also be oriented at an angle to the shearbar 38 in a manner known per se in order to achieve a pulling cut (see DE 44 18 697 A1).

To detect the sharpness of the cutting edges of the knives 40 and their distance from the shearbar 38 are at the

Counter blade 38 two sensors 42 attached or embedded therein. The sensors 42 each have a sensitive area which extends over the knives 40 of two rows, i.e. interact with the inner end areas of the knives 40 of the outer rows and the outer end areas of the knives 40 of the inner rows.

However, in another embodiment, the sensors 42 may be associated with only one row at a time (then four sensors 42 could be provided along the bedknife 38) or only a single sensor 42 associated with or across a single row of knives 40 is used Width of the chopping drum 22 is moved by, for example, on a carriage

Grinding device 58 is attached.

As is well known per se, the sensors 42 operate in an inductive manner and comprise a permanent magnet and a magnetic field sensor (e.g. induction coil, Hall sensor or

Magnetoresistive sensor) that outputs a signal. This signal changes when the (ferromagnetic) cutting edge of knife 40 passes sensor 42 . Based on the time course of the signal, e.g. the height and length of a pulse when passing a

Knife 40, an evaluation device 50 calculates a

Initial value with regard to the sharpness of the knives 40 and/or the

Distance of the knives 40 from the sensor 42 or from the shearbar 238, given a known positioning of the sensor 42 relative to the shearbar 38. For details of the sensors and

9 BE2022/0032

Evaluation of the signals is referred to the disclosures of DE 10 2011 005 317 B4 and DE 10 2014 218 408 A1 and those cited there

Documents incorporated herein by reference

documents are included.

The evaluation device 50 is equipped with a

Operator interface 52 is connected to a display device, on which the output values with regard to the sharpness of the knife 40 and/or the distance of the knife 40 from the shearbar 38 can be displayed separately for each knife 40. In addition, the

Evaluation device 50 on the display device

Display operator interface 52 when it is appropriate to perform maintenance on a blade 40, particularly if it is very blunt and needs to be replaced, or is excessively tall

is at a distance from the shearbar 38 and must therefore be repositioned (cf. EP 3 354 126 A1).

In order to be able to assign the individual output values with regard to sharpness and distance to specific knives 40 without requiring a separate sensor for detecting the angle of rotation of the chopper drum 22, there are two knives 40 on the chopper drum 22 between two consecutive knives 40 in the circumferential direction

Reference body 54 attached. The reference bodies 54 are made of ferromagnetic material and each one of the sensors 42 is arranged within the sensitive area and can thus be detected by the sensors 42 . The shape of the reference body 54 is basically arbitrary, as long as it differs from a cutting edge of a

Knife 40 in one by the sensor 42 and the

Evaluation device 50 distinguishable way differs. For example, the reference body 54 can be cylindrical.

Thus, if a reference body 54 with rotating

Chopping drum 22 passes a sensor 42, are the

Magnetic field sensor of the affected sensor 42 from a signal that differs in terms of width and / or height of the signal generated by a passing cutting edge of a knife 40.

10 BE2022/0032

In particular, the signal will have a smaller amplitude and a greater temporal length than that of the cutting edge. The

The magnetic field sensor of the sensor 42 thus also generates signals that enable the evaluation device 50 to determine the time of the

To detect passing of the reference body 54 and in time

to relate to the signals that are generated when passing the

Cutting edges of the knives 40 arise. If the direction of rotation of the chopper drum 22 is known, the starting values with regard to the sharpness and the spacing of the individual knives 40 can also be

Position of the individual knife 40 relative to the reference body 54 are assigned. Thus, the first knife 40 of the first row assigned a specific value for sharpness and distance and on the

Display of the operator interface 52 are displayed, which applies analogously to all other knives 40. In addition, if necessary, the operator can be informed that the nth knife in the mth row requires maintenance.

The signals based on the reference body 54 can also be used by the evaluation device 42 to determine the

Speed of the chopper drum 22 are used. This speed can be used to set or regulate the speed of the feed rollers 30 to 36, and the number of distributed around the circumference of the chopping drum 22 can be based on the speed and the signals emitted by the sensor 42 when the cutting edges of the knives pass

Knife 40 are determined. This number serves on the one hand for

Control of the display (because the initial values for the determined number of knives 40 are displayed) and on the other hand also for

Control of the cut length by supplying information regarding this number to a cut length control, analogous to

Procedure according to DE 10 2009 046 821 A1.

Claims (9)

11 BE2022/0032 CLAIMS 1. Arrangement for detecting the sharpness and / or the distance between knives (40) of a chopping drum (22) of a forage harvester (10), comprising: a rotatably and drivably mounted chopping drum (22), around the circumference of which a number of knives (40) are distributed; a sensor (42) configured to interact with the knives (40) by sensing changes in a magnetic field caused by the tip of a passing knife (40); and an evaluation device (50) which is configured to provide an output value with regard to the sharpness of the knives (40) and/or the distance of the knives (40) from the sensor (42) on the basis of a signal from the sensor (42); characterized in that a reference body (54) is arranged on the chopper drum (22) between two knives (40) following one another in the circumferential direction and causes a detectable signal from the sensor (42) when passing the sensor (42), and in that the evaluation device (50) is configured to identify the signal generated when the reference body (54) passes the sensor (42) and to use it to determine a value with regard to the rotational position and/or speed of the chopper drum (22). 2. Arrangement according to claim 1, wherein the evaluation device (50) is configured to assign the initial value to individual knives (40) on the basis of the identified value for the rotational position of the chopper drum (22). 3. Arrangement according to claim 2, wherein the evaluation device (50) is configured to use the rotary position and the initial value to display a display associated with the individual knives (40) with regard to the sharpness and/or distance from the sensor (42) and/or information derived therefrom to provide an operator and/or an indication of the rotational speed of the cutterheads (22) on an operator interface (52). 12 BE2022/0032 4. Arrangement according to one of claims 1 to 3, wherein the evaluation device (50) is configured to use the value of the identified speed and the signal from the sensor (42) to determine the number of knives (40) distributed around the circumference of the chopper drum (22). to identify. 5. Arrangement according to claim 4, when dependent on claim 3, wherein the evaluation device (50) is set up to configure the display on the basis of the identified number of knives (40). 6. Arrangement according to claim 4 or 5, wherein the evaluation device (50) is configured to feed the value of the speed and the identified number of knives (44) to a cut length check. 7. Arrangement according to one of the preceding claims, wherein the sensor (42) comprises a magnet and a magnetic field sensor. 8. Arrangement according to one of the preceding claims, wherein the sensor (42) comprises a sensitive area which is associated with one or two rows of knives (40) of the chopping drum (22) arranged next to one another and distributed around the circumference. 9. Forage harvester (10) with an arrangement according to one of claims 1 to 8.