EP3497269B1 - Method and device for detecting an overload at a bale opener - Google Patents

Description

The invention relates to a method and a device for detecting an overload on a bale opener.

Bale openers are known per se. They have milling drums which rotate in relation to a floor on which the fiber bales rest about an axis of rotation which extends generally perpendicularly to the path of travel of the respective milling drum. By rotating and moving, these rollers mill off the respective fiber bale on a side facing away from the ground and thus loosen part of the fiber material from the respective fiber bale. The milling drums run over the fiber bales several times until the fiber material is almost completely removed. This can be done by moving the milling drums back and forth or continuously in one direction along a circular line.

The method for producing such fiber bales causes the fiber material to have a lower density in the edge areas facing and away from the ground than in the central, so-called core area. As a result, the milling drums have to remove less fiber material in the edge area with the same feed rate and are therefore less stressed. The bale opener can work with almost normal load. If the milling drum moves further towards the core area due to the feed, it has to extract more fiber material, which increases the load on the bale opener. If you consider that fiber bales usually also contain foreign material, the load on the drive associated with the respective milling drum increases. In addition to the increased Energy absorption can damage the milling head. But the milling drums themselves can also be overloaded. In this context, overload means exceeding the usual load limits in normal operation. i.e. it does not necessarily have to be a load condition in which there is a risk of damage to the bale opener. In order to avoid this, it is known to vary the speed and/or traversing speed of the milling drum depending on the consistency of the fiber bales. This has the disadvantage that the drive runs very discontinuously when in doubt. In addition, there are very frequent and possibly strong positive or negative accelerations on the drive. In connection with the resulting alternating loads, the frame of the bale opener must be designed accordingly. Such an overload can also be so short that damage to the bale opener is not to be feared and therefore no change should actually be made during ongoing operation of the bale opener. Therefore, it is known as a development to take into account the duration of the continuous existence of such an overload. If a certain period of time is exceeded, ie there is a risk of damage to the bale opener or objects on the fiber bale to be removed, a corresponding reaction takes place, for example by switching off the bale opener. However, this type of monitoring is quite sluggish. In addition, the reaction does not always take place at the same speed, as this depends on the travel speed of the milling drum(s).

From the WO 2009062325 A1 a bale removal machine with a mobile removal tower and a height-adjustable removal arm attached to the removal tower is known. A take-off roller and a take-off roller drive are held on the take-off arm. In order to avoid blockages within the bale removal machine, there are means for measuring the power consumption of the removal roller drive during a removal process.

By measuring and evaluating the measurement data, taking into account the corresponding idle values, an actual value for the removal rate or an actual value proportional to the removal rate should be calculated. This actual value is to be compared in the controller with specified values and the removal rate is to be monitored with it. If this monitoring shows that a specified limit value is being exceeded, measures to reduce removal capacity can be initiated by the controller. These include, for example, reducing the driving speed of the removal tower, reducing the removal depth or adjusting the speed of the removal roller. It is considered disadvantageous that the drive runs very discontinuously when in doubt.

The object of the invention is to counteract the aforementioned disadvantages.

This object is solved by the subject matter of claims 1 and 9. Advantageous developments are specified in the dependent claims. According to the invention, a method for operating a bale opener with at least one milling drum is provided. By rotating this at least one milling drum about an axis of rotation and by moving it along a predetermined travel path at an acute or right angle to the axis of rotation, the bale opener is able to mill off a fiber bale. This loosens fiber material from the fiber bale. The method includes an initial step. In this step, it is detected when an overload occurs on one or all of the monitored milling drums. This can be done, for example, by monitoring the power consumption of the milling drum drive. If such an overload is detected, a transition is made to a determination step. In the determination step, the presence of an overload condition is determined. This is achieved according to the invention when the initially mentioned, detected overload has occurred continuously along a path covered by the or the monitored milling drum(s). This path must be equal to or greater than a predetermined distance. i.e. the overload condition is independent of time and does not occur instantaneously if an overload exists at all. i.e. A continuous overload can also occur if the traversing speed of the bale opener's milling head decreases and possibly drops to 0. If this is an overload reaction of the bale opener, provision can be made to restart the determination of the overload state after the milling head has restarted. Once such an overload condition has been determined to exist, a tripping step is entered. The triggering step itself involves triggering an overload response. This can include switching off the bale opener, for example. The predetermined path can be chosen to be very short in order to enable obstacle detection; Drive values such as travel speed no longer play a role.

The overload reaction preferably includes signaling the determined overload condition to the outside with respect to the bale opener, for example in the form of a siren sound. Alternatively or additionally, it includes switching off the bale opener or just reducing the travel speed of the milling head and/or a respective speed of at least the monitored milling drum(s) on which the overload existed at the time the overload condition was determined.

Alternatively or additionally, the method may additionally include a step of jumping back to the initial step. According to the invention, this jumping back takes place when it has been determined in the determination step that the overload has ceased and that the distance covered by the at least one milling drum is shorter than or equal to the predetermined one distance is. i.e. there is neither an obstacle nor damage to the bale opener to be feared. Reliability is increased and downtimes are minimized.

Alternatively or additionally, the springing back can take place when the direction of movement of the at least one milling drum changes. The reason for this is that the milling drum(s) is/are moving away from the supposedly existing obstacle.

Again alternatively or additionally, jumping back can occur when the triggering step is completed, either immediately or triggered. The pushing can be done by a person, for example. In all three of the above cases, downtimes are largely avoided.

In each of the aforementioned methods, the predetermined distance can essentially correspond to a dimension of the fiber bale along the travel path of the at least one milling drum. This makes it possible to take account of the different nature of the fiber bales that may be arranged one behind the other.

In the case of a bale opener with several milling drums arranged one behind the other along the travel path, in the above-mentioned method in the determination step in the case of monitoring several milling drums at the same time, reference can be made to a common overload on the distance covered by the milling drum in front in the travel direction of the milling drums. The background to this is that the area behind the front milling drum in the direction of travel is neither a danger area nor an area in which there is a new source of overload.

In the case of monitoring individual milling drums for overload, reference is preferably made to the milling drum(s) with regard to the distance covered, for which an overload has been detected and continues to exist. i.e. the milling drum(s), which is/are running without overload, are not taken into account, which has advantages in monitoring data processing.

If the bale opener has several milling drums, in the case of monitoring individual milling drums in the determination step in the above-mentioned method, if the overload on a monitored milling drum ceases, another of the milling drums with overload is preferably monitored. The aforementioned distance covered is a sum of the distance covered by one milling drum up to the time when the overload on one milling drum ceased and the distance covered by the other milling drum from the time when the overload on one milling drum ceased. The process therefore adapts dynamically to the load situation of the milling drums and thus offers greater safety.

In each of the aforementioned methods, the determination can be made by monitoring the power consumption of a drive of the at least one milling drum and/or the bale opener as a whole. In the simplest case, the determined (measured) value is supplied to a threshold circuit. If a predetermined threshold value is exceeded, an overload is determined to be present.

Advantageously, each of the above methods can be computer-implemented. The implementation can take place in the bale opener itself and/or in an external device such as a central control system. The coupling can take place, for example, by bus. Furthermore, a bale opener is provided according to the invention, which can be equipped in accordance with the aforementioned statements, ie with one or more milling drums. If there is only one milling drum, the bale opener is set up to be operated according to one of the aforementioned methods, in which only one milling drum is monitored. If the bale opener has several milling drums, it can be set up according to the invention to be operated according to any of the aforementioned methods.

The bale opener has a load monitoring device. The load monitoring device is set up to detect the overload on the monitored milling drum(s). In the simplest case, it is a current detection circuit with downstream threshold value determination logic.

In addition, the bale opener has a displacement detection device. According to the invention, the path detection device is designed to determine the path covered by the relevant milling drum(s). In the simplest case, it is an incremental encoder whose incremental disk is rotated with the movement of the milling drum(s).

In addition, the bale opener includes a protective device. This protective device is set up to trigger or execute the overload reaction when the overload condition is determined.

Figur 1

eine Ballenfräsanordnung und

Figur 2

ein Verfahren zum Betreiben des Ballenöffners von Figur 1, gemäß einer Ausführungsform der Erfindung.

Further features and advantages of the invention result from the following description of preferred embodiments. Show it:

figure 1

a bale cutter assembly and

figure 2

a method of operating the bale opener of figure 1 , according to an embodiment of the invention.

figure 1 shows an arrangement 1 with a bale opener 10 and fiber bales 2 - 6 arranged in a row below its milling head 11 along their travel path sv.

At the right end of the bale opener 10 there is an output section 16 for the fibers that have been detached from the fiber bales 2-6 by means of milling drums 12 of the milling head 11. At the left end there is, for example, a control device 14, on the top of which an operating terminal 15 for operating the bale opener 10 is arranged.

The fiber bales 2-6 are lined up next to one another in a known manner and, viewed vertically, have zones of different density. The uppermost zones (hz (2, 3) - hz (6, 3)) show the lowest density. The central, so to speak core area of the respective fiber bale 2 - 6 arranged underneath has a respective height hz (2, 2) - hz (6, 2). Below that there is a third zone with a height _hZ (2, 1) - _hZ (6, 1) with a lower density than the core area, which is, for example, higher than the density of the uppermost zone hz (2, 3 ) - Hz (6, 3). In relation to the values hz (i, j) it should be mentioned that i indicates the number of the respective fiber ball 2 - 6 and j the number of the respective zone. The heights of the zones of the individual fiber balls can differ from one another.

Furthermore, for example, there is a foreign part 7 in the left fiber bale 2. If the milling head 11 along the travel path sv moves horizontally to the right gradually over the fiber bales 2 - 6, their fibers are removed one after the other from top to bottom and in a known manner via the output section 16 passed on to downstream machines in the production chain, such as cleaners. This is done by moving the milling head 11 or the frame 13 to which it is attached.

If the milling head 11 with its rollers 12 gets into the area of the foreign part 7, it can happen that the foreign part 7 leads to an overload on the motor-driven milling rollers 12. This can be detected by control technology, for example, by means of an increased motor current consumption of the drive motors.

In order to prevent the bale opener 10 from being stopped unnecessarily, the control device 14 preferably checks the route along which this overload occurs.

If the milling drum 12 on the left here has run over the foreign part 7 , in the example shown the right milling drum 12 has not yet come into contact with the foreign part 7 . The result of this is that the overload that has occurred in the process is eliminated again. If the foreign part 7 were now so large that the right-hand milling drum 12 drives over the obstacle as long as the left-hand milling drum 12 is also driving over it, or immediately after the left-hand milling drum 12 has passed the obstacle has lost contact with the foreign part 7, a persistent presence of the overload would preferably be determined. i.e. both milling drums 12 are advantageously monitored. However, the monitoring can be limited to the milling drum 12 located at the front in the travel direction.

If the width dimension of the fiber bales 2 - 6 , which are usually essentially the same width, is specified here as the minimum travel path, the result is that the milling head 11 is not stopped at all. Compared to conventional solutions, this has the advantage that the bale opener 10 is not stopped unnecessarily.

If the milling head 11 with its milling drums 12 reaches, for example, the core area of the fiber bale 4 in the middle here, and it is assumed that the density of this fiber bale 4 leads to an overload on the respective milling drum 12 when driving over it, the control device 14 would determine along which route it was covered the overload occurs continuously.

Provision is preferably made here for the load values on the milling drums 12 or overloads detected on them to be combined with one another in a logical OR. This means that, assuming that the milling head 11 moves from left to right in figure 1 is moved over the fiber bale 4, first the right-hand milling roller 12 comes into contact with the core area (identified by h _Z (4, 2)). This results in an overload on this milling drum 12 . In the example shown, the left milling drum 12 also comes into contact with this core area at some point, so that an overload also occurs here. This overload on the left milling drum 12 remains, even if the right milling drum 12 has already reached the right fiber bale 5. Is as a default path or as a default If, as indicated above, the width of the fiber bales 2 - 6 in Figure 1 is the criterion for the overload reaction, this would occur even if the right-hand milling roller 12 has re-emerged from the core area of the fiber bale 4, and this is completely independent of the travel speed of the milling head 11.

The overload reaction can result, for example, in a reduction in the speed of the overloaded milling drum(s) 12 and/or in the travel speed of the milling head 11 .

Alternatively, provision can be made for the milling head 11 to be raised somewhat relative to the floor 8 (vertically upwards in figure 1 ), so that the milling drums 12 can no longer penetrate so deeply into the relevant core area. In order to be able to maintain the feed specified for the fiber bales 2-6, it can be provided that the fiber bale 4 is moved back and forth until its current feed is reached. Only then would the fiber bale 5 be continued according to the invention.

figure 2 shows a method provided for this purpose according to an embodiment of the invention.

After a milling process has started in step S1, a subsequent step S2 checks whether an overload has been detected. If this is not the case (no branch after step S2), in a subsequent step S5 the query is made as to whether the milling process is still being carried out in terms of control technology. If this is the case (yes branch after step S5), the process jumps back to step S2.

If the milling process is ended (No branch after step S5), the method is ended in a subsequent step S6.

If an overload was detected in step S2 (yes branch after step S2), it is checked in a subsequent step S3 whether the distance covered corresponds to a predetermined distance or exceeds it. The distance covered is the distance covered by the milling head or its milling drums 12 from the point in time at which the overload was first detected and has continued continuously since then.

If the distance covered is less than or equal to the specified distance (no branch after step S3), the process jumps to step S5. This ensures continuous monitoring for a permanently existing overload.

If the distance covered is greater than or equal to the specified distance (yes branch after step S3), the aforementioned overload reaction takes place in a subsequent step S4.

After the overload reaction has taken place, which can include a restart of the milling process, for example, a jump is made back to step S2. Alternatively, the process jumps to step S6 and ends the process.

The invention is not limited to this embodiment.

The method can be applied to any type of bale opener.

If an overload condition has been determined, an external signaling is preferably provided in relation to the bale opener 10, be it on the bale opener 10 itself (warning light, warning tone, ...) and/or at a control center.

The continuous presence of an overload can be checked by means of a polling mechanism or as part of a push mechanism. The polling mechanism periodically (for example every hundredths of a second) checks whether there is an overload. With the push mechanism, on the other hand, the checking mode is triggered in step S3 when an overload has been detected for the first time. After that, a distance measuring device, for example an incremental encoder, is started and the distance covered by the milling head 11 is determined. If the determined distance is greater than or equal to the specified distance, an overload reaction occurs.

If the overload disappears in the meantime, the path determination is simply switched off. In the simplest case, this can be done by means of a threshold value circuit. If the motor power consumption of the drive motors of the milling drums 12 exceeds a predetermined value (overload), for example, the control device 14 is instructed to start path detection. If the overload reaction has taken place in the meantime, the travel encoder is switched off.

If, on the other hand, the distance covered is greater than or equal to the specified distance without the distance detection having been switched off by means of the threshold value determination, it is clear that the overload has existed permanently.

Instead of or in addition to the monitoring by means of the control device 14 of the bale opener 10 itself, the monitoring can also take place centrally.

If the milling head 11 moves over the in figure 1 right fiber bale 6 to the right, the direction of the milling head 11 changes as soon as, for example, the right milling drum 12 has left the fiber bale 6 at the right end or a sensor detects that the milling drum 12 has reached the right edge of the fiber bale 6.

If an overload has been detected in relation to the fiber bale 6, it can be provided when the direction of the milling head 11 changes that the path detection is restarted. Alternatively, provision can be made to continuously continue the path detection if the overload persists, and this preferably in relation to the front milling roller 12 in the direction of the fiber bale 1.

Instead of monitoring the power consumption at the milling drum drive, the power consumption of the entire bale opener 10 can also be monitored or used for overload detection. This has the advantage that there are usually already existing circuits in the bale opener 10, which has a favorable effect on the costs.

As a result, the invention forms a very simple way of reliably detecting obstacles and largely avoiding false triggering due to an overload on the milling drums 12 .

Reference List

1

arrangement

2

fiber bale

3

fiber bale

4

fiber bale

5

fiber bale

6

fiber bale

7

foreign part

8th

Floor

10

bale opener

11

milling head

12

milling drum

13

frame

14

control device

15

operator terminal

16

output section

v

traversing or removal path

hZ(i,j); i, j ∈ N

Height of a fiberball zone

Sk; k ∈ N

Step

Claims (9)

1. Method for operating a bale opener (10) having at least one cutting roll (12) by means of the rotation of which about a rotational axis and the movement of which along a predetermined travel path (sv) at an acute or right angle to the rotational axis the bale opener (10) is able to cut into a fibre bale (2-6) and thus detach fibre material from the fibre bale (2-6), comprising

   • a starting step (S2)

   - of detecting if an overload occurs at one or at all the monitored cutting roll(s) of the at least one cutting roll (12), and

   - of proceeding to a determination step (S3) if such an overload has been detected,

   • an initiation step (S4) of initiating an overload response, characterised by

   • the determination step (S3)

   - of determining the presence of an overload state if the detected overload has occurred continuously along a path covered by the monitored cutting roll(s) (12) that is equal to or greater than a predetermined distance, and

   - of proceeding to the initiation step (S4) if such an overload state has been determined.
2. Method according to claim 1, wherein the overload response comprises

   • signalling the determined overload state externally in relation to the bale opener (10), and/or

   • stopping the bale opener (10) or reducing a rotational speed and/or travelling speed of at least that/those monitored cutting roll(s) (12) at which the overload was present at the time at which the overload state was determined.
3. Method according to any one of the preceding claims, further comprising a step of returning to the starting step (S2) if

   • it has been determined in the determination step (S3) that

   - the overload has ceased and

   - the path covered by the at least one cutting roll (12) is shorter than or equal to the predetermined distance,

   • a direction of movement of the at least one cutting roll (12) changes, and/or

   • after the initiation step (S4) has been carried out

   - directly or

   - when triggered.
4. Method according to any one of the preceding claims, wherein the predetermined distance corresponds substantially to a dimension of the fibre bales (2-6) along the travel path (sv) of the at least one cutting roll (12).
5. Method according to any one of the preceding claims, wherein, in the case of a bale opener (10) having a plurality of cutting rolls (12) arranged one behind the other along the travel path (sv), in the determination step (S3)

   • in the case where a plurality of cutting rolls (12) is monitored at the same time for a common overload, reference is made to the path covered by the cutting roll (12) that is at the front in the direction of travel of the cutting rolls (12), and

   • in the case where individual cutting rolls (12) are monitored for overload, reference is made in respect of the path covered to the cutting roll(s) (12) at which an overload has been detected and persists.
6. Method according to claim 5, wherein, in the case where individual cutting rolls (12) are monitored in the determination step (S3), if the overload at one monitored cutting roll (12) ceases,

   • another of the cutting rolls (12) with overload is monitored, and

   • the path covered is a sum of

   - the path covered by the one cutting roll (12) up to the time at which the overload at the one cutting roll (12) ceased and

   - the path covered by the other cutting roll (12) from the time at which the overload at the one cutting roll (12) ceased.
7. Method according to any one of the preceding claims, wherein the determination of the overload comprises a step of monitoring a current consumption

   • of a drive of the at least one cutting roll and/or

   • of the bale opener (10) as a whole.
8. Method according to any one of the preceding claims, wherein the method is implemented by computer.
9. Bale opener (10) having at least one cutting roll (12) by means of the rotation of which about a rotational axis and the movement of which along a predetermined travel path (sv) at an acute or right angle to the rotational axis the bale opener (10) is able to cut into a fibre bale (2-6) and thus detach fibre material from the fibre bale (2-6), comprising a load monitoring device which is adapted to detect an overload at the monitored cutting roll(s) (12), and a protecting device which is adapted to initiate or implement an overload response if an overload state is detected, characterised in that the bale opener comprises a path determining device which is configured to determine a path covered by the cutting roll(s) (12) in question, and in that the bale opener is configured to be operated in the case where there is a single cutting roll (12) in accordance with a method according to any one of claims 1 to 4 and in the case where there is a plurality of cutting rolls (12) according to any one of claims 1 to 8.

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