BE1024683B1 - CUTTERBOARD WITH A SET OF DRIVING ELEMENTS - Google Patents

Abstract

Agricultural vehicle (1) with a header (5) containing a series of units, each row unit including a feed / grab unit (10) and a chopping unit (11), the header containing a first power transmission axis (16) around the feed / grab units (10) and the header comprises a second power transmission shaft (17) which is connected via a drive line (18) to a drive (19) of the agricultural vehicle, wherein each chopping unit (11) contains a safety coupling (22) and is connected by means of the safety coupling with the second power transmission shaft (17), wherein at least one torque sensor (29) is arranged on the second power transmission shaft (17), the drive line (18) or the drive (19), the torque sensor (19) being operatively connected to a device for monitoring the coupling swing, which can recognize a predetermined change in the coupling swing that indicates that a safety coupling (22) is slipping, wherein this device for monitoring the coupling swing is operatively connected to a user interface to report the slipping of a safety coupling .

Description

(30) Priority data:

(73) Holder (s):

CNH Industrial Belgium nv 8210, ZEDELGEM Belgium (72) Inventor (s):

TERRYN Mathieu M.A. 8610 KORTEMARK Belgium

BORRY Stijn 8740 PITTEM Belgium

VANDERGUCHT Yvan C.C. 8647 LO-RENINGE Belgium

YSEBAERT Maarten 8700 TIELT Belgium (54) CUTTER WITH A RANGE OF ELEMENTS (57) Agricultural vehicle (1) with a cutterbar (5) containing a series of units, each row unit containing a feed / grab unit (10) and a chopping unit (11), the header comprising a first power transmission shaft (16) to drive the feed / gripping units (10) and the header comprising a second power transmission shaft (17) connected to a drive (19) of the agricultural vehicle via a drivetrain (18) wherein each chop egg unit (11) contains a safety coupling (22) and is connected by means of the safety clutch to the second power transmission shaft (17), with at least one torque sensor (29) mounted on the second power transmission shaft (17), the drivetrain (18) or the drive (19), the torque sensor (19) being operationally connected to a Torque swing monitoring device, which can recognize a predetermined torque swing change indicating that a safety clutch (22) is slipping, this torque swing monitoring unit operatively connected to a user interface to report a safety clutch slip .

FIG. 1

BELGIAN INVENTION PATENT

FPS Economy, K.M.O., Self-employed & Energy

Publication number: 1024683 Filing number: BE2016 / 5791

Intellectual Property Office

International classification: A01D 75/18 A01B 61/02 A01D 45/02 Date of issue: 25/05/2018

The Minister of Economy,

Having regard to the Paris Convention of 20 March 1883 for the Protection of Industrial Property;

Having regard to the Law of March 28, 1984 on inventive patents, Article 22, for patent applications filed before September 22, 2014;

Having regard to Title 1 Invention Patents of Book XI of the Economic Law Code, Article XI.24, for patent applications filed from September 22, 2014;

Having regard to the Royal Decree of 2 December 1986 on the filing, granting and maintenance of inventive patents, Article 28;

Having regard to the application for an invention patent received by the Intellectual Property Office on 21/10/2016.

Whereas for patent applications that fall within the scope of Title 1, Book XI, of the Code of Economic Law (hereinafter WER), in accordance with Article XI.19, § 4, second paragraph, of the WER, the granted patent will be limited. to the patent claims for which the novelty search report was filed, when the patent application is the subject of a novelty search report indicating a lack of unity of invention as referred to in paragraph 1, and when the applicant does not limit his filing and does not file a divisional filing in accordance with the search report.

Decision:

Article 1

CNH Industrial Belgium nv, Leon Claeysstraat 3A, 8210 ZEDELGEM Belgium;

represented by

BEETZ Joeri, Leon Claeysstraat 3A, 8210, ZEDELGEM;

a Belgian invention patent with a term of 20 years, subject to payment of the annual fees as referred to in Article XI.48, § 1 of the Economic Law Code, for: HEADER WITH RANGE OF ELEMENTS.

INVENTOR (S):

TERRYN Mathieu M.A., Hoogledestraat 53, 8610, KORTEMARK;

BORRY Stijn, Kwiekmotestraat 6, 8740, PITTEM;

VANDERGUCHT Yvan C.C., Lo Street 4, 8647, LO-RENINGE;

YSEBAERT Maarten, Hooitstraat 4, 8700, TIELT;

PRIORITY:

BREAKDOWN:

Split from basic application: Filing date of the basic application:

Article 2. - This patent is granted without prior investigation into the patentability of the invention, without warranty of the Merit of the invention, nor of the accuracy of its description and at the risk of the applicant (s).

Brussels, 25/05/2018,

With special authorization:

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Cutting table with a series of driving elements

BACKGROUND OF THE INVENTION

This invention relates to a harvester for agricultural applications (hereinafter referred to simply as harvester) consisting of a header with a series of row elements extending along the width of the header.

The term combine harvester (or picker, combine in English) for a harvester has grown historically because this machine combines a number of harvesting functions in a single harvesting unit, such as picking, threshing, separation and cleaning. Thus, a combine harvester contains a header on a front end which is suitable for cutting the cut crop material from a field. The agricultural vehicle carries the cutter bar through a feed system suitable for removing the crop material removed from the field by the header. transport the main body of the vehicle. Threshing rotors are usually mounted in the main body of the vehicle to perform threshing operations on the crop. Further cleaning systems are included in the main body of the vehicle, so that crop and remains can be optimally separated.

More particularly, this invention relates to a harvester carrying a header with a series of row elements in the width of the header. Such headers are known in the art, for example, as maize headers or sunflower headers. Each row element contains a feeding / gripping unit. The feed / grab unit usually includes a pair of stripper plates spaced apart and extending in a forward direction of travel of the agricultural vehicle carrying the header. The feed / gripping unit further includes a pair of stem rollers positioned below the stripper plates, and a pair of collection chains for moving the stems into the space between the stripper plates. The feeding / gripping unit pulls the stem down through the pair of stripper plates. In addition, the distance between the stripper plates is chosen so that the heads of the harvesting material, for example the maize ·· or sunflower heads, are too large to pass through the stripper plates so that they can be pulled from the stem.

Each row element further includes a chopping unit. When the stems are pulled down through the stripper plates, the chopping unit chops the stems into pieces.

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It is also clear that other remnants such as leaves are chopped into pieces (chopped) together with the stems. These pieces are then scattered across the field.

US patent 2015/0305240 describes an agricultural vehicle with a header with such an arrangement. This document describes how the feeding / gripping unit and the chopping units are driven separately. By driving these units separately, the operating speed of the feed gripping unit can be controlled independently of the operating speed of the chopping unit. More specifically, the chopping units are known to consume a lot of energy. Therefore, being able to reduce the operating speed of the chopping unit in predetermined situations would allow a significant reduction in energy consumption.

A disadvantage of separately driving the feeding / gripping units and the chopping units relates to the safety coupling usually arranged between a driving line and the chopping units. The safety clutch is fitted between each chopping unit and the drive shaft and can slip when the chopper load exceeds a defined threshold. The operation of the feeding / gripping unit can be visually checked from the cabin of the agricultural vehicle. In other words, an operator can see if the feeding / gripping unit is working correctly. However, since the chopping units are located below the feed / gripping units, they cannot be seen from the cab of the agricultural vehicle. When the feed gripping units are physically coupled to the chopping units, slipping of a safety clutch can be visually detected by the operator since such slipping of a safety clutch would stop both the feeding / gripping unit and the chopping unit. When the feed / gripping unit drive system is separated from the chopper drive system, slippage of a safety clutch in the chopper unit cannot be visually detected by the operator. As a result, an operator will continue to drive with a slipping safety clutch, permanently damaging the safety clutch mechanism. Replacing a damaged safety coupling is laborious and time consuming, and therefore very expensive.

It is an object of this invention to provide a mechanism that allows early detection of coupling activation.

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SUMMARY OF THE INVENTION

To this end, the invention provides an agricultural vehicle with a header comprising a series of row units in the width of the header, each row unit of the series of row units comprising a feed / gripping unit and a chopping unit, where the header contains a first power transmission shaft along the series driving units extends around. drive the feed / gripping units of the row unit series and the header comprises a second power transmission shaft connected via a drive train to an agricultural vehicle drive, each chopping unit including a safety clutch and connected by the safety coupling to the second power transmission shaft, with at least one torque sensor mounted on one of the following elements: the second power transmission shaft, the drivetrain and the drive, the torque sensor being operationally connected to a torque fluctuation monitoring device, causing a predetermined change can be recognized in the torque swing, indicating the slip of a safety clutch, this torque swing monitoring device being operationally connected to a user interface to report a safety clutch slip.

The invention is based on the insight that the slipping of a safety coupling changes the torque fluctuation. By monitoring the torque fluctuation, the slip of a safety clutch can therefore be detected when a change in the torque fluctuation is recognized. This can be communicated to a user via a user interface. In addition, situations can be prevented in which a safety coupling is activated without the operator noticing it, whereby the safety coupling is permanently damaged. In the agricultural vehicle according to the invention, the slipping of a safety coupling is reported via a user interface, so that an operator of the vehicle can immediately respond to the slipping. The invention has the additional advantage that it does not require a sensor in elite individual safety coupling. Fitting a sensor in any safety clutch would result in appropriate wiring being fitted across the entire header, this wiring being easily damaged by the harsh working conditions in which header headers usually operate. In the invention, a single torque measurement is sufficient to detect the slip of a safety coupling. For an operator and for damage to the skidding

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BE2016 / 5791 safety coupling, it is irrelevant to know which of the series of safety coupling slips. Tests have shown that via the torque sensor in one of the two elements, ni. the powertrain of the power transmission shaft and the drive, can be reliably measured when at least one safety clutch slips. In addition, the technical elements required to detect such a slip are easy to install. The inventive mechanism informs an operator about the slip of a safety clutch so that damage can be prevented.

The torque sensor preferably contains at least one load sensor. A load sensor is usually mounted on an outer surface of an axle. For example, a load sensor can take the form of a strain gauge. Furthermore, the torque sensor is preferably attached to at least one of two elements, ni. the power transmission shafts and the drivetrain. This is based on the understanding that the load on the shaft and / or the drivetrain is directly proportional to the torque transmitted by the shaft and / or the drivetrain. Since the load is directly proportional to the torque, the torque can be measured by a load sensor. This makes a load sensor a kind of torque sensor.

Preferably, the torque swing monitoring device is capable of measuring an amplitude of the torque swing in at least one frequency range, the torque swing monitoring device recognizing the change by an amplitude deviation over time within the at least one frequency range. The at least one frequency range can be determined based on knowledge and / or experience as the at least one frequency range at which an amplitude changes when a coupling slips.

Preferably, an amplitude threshold is set for at least one frequency range, and the torque fluctuation monitoring device recognizes the change when the amplitude within the range exceeds the threshold. Tests and measurements have shown that one or more frequency ranges can be selected in which the amplitude exceeds a predetermined threshold when a safety clutch slips. By using electronic signal processing means, crossing a threshold within a predetermined range can be easily determined.

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Preferably, the power transmission shaft is connected via a further drive train to a second drive of the agricultural vehicle. The power transmission shaft drives the feed / gripping unit. By connecting them to a separate drive of the agricultural vehicle, the operating speed of the feeding / gripping unit can be selected independently of the operating speed of the chopping units.

The invention further relates to a method for detecting the slipping of the safety coupling between a forage harvester and a row unit of an cutterbar of an agricultural vehicle, the method comprising the following steps:

driving the forage harvester via the safety clutch through a power transmission shaft which can be a drivetrain connected to a drive of the agricultural vehicle;

measuring a torque in at least one of three elements: ni. the power transmission shaft, the drivetrain and the drive train;

detecting a predetermined change in the torque fluctuation indicating the slip of a safety clutch; and reporting the detected slipping of a safety link through a user interface.

The method of the invention includes the steps mainly corresponding to the use of the above-described agricultural vehicle. Thus, many of the effects and advantages described above with respect to the agricultural vehicle also apply to the method of the invention. By using the method of the invention, slipping of a safety clutch can be detected and reported to an operator via a user interface. This makes it possible, in the construction of the header, to separate the driving elements of the feed / gripping unit from the driving elements of the chopping unit without any operational disadvantages. As a result of this separation, the header with higher energetic efficiency can be used, as described above. However, due to the separation, slipping of a safety coupling cannot visually detect walls by an operator from the cab of the agricultural vehicle. By means of the method of the invention, the operator is informed at an early stage about the slipping of a safety coupling. This allows the operator to respond appropriately to avoid permanent damage to the safety coupling.

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Preferably word! the torque measured by measuring a load through at least one load sensor connected to at least one of the two elements, ni. the power transmission shaft and drivetrain are attached. The load on the power transmission shaft or drivetrain is directly proportional to the torque transmitted through the power transmission shaft and drivetrain. Thus, a load measurement can provide information about the torque.

The torque is preferably measured by measuring a torque fluctuation amplitude in at least one frequency range. Furthermore, detecting a predetermined change of the torque wobble preferably includes recognizing a predetermined change of the torque wobble amplitude in at least one frequency range. Furthermore, preferably recognizing a predetermined deviation consists in detecting exceeding a predetermined amplitude threshold. As described above, at least one frequency range can be determined in which the amplitude of the torque oscillation increases above a predetermined threshold when a safety clutch slips. A simple signal processing means can be used to detect such exceeding of a predetermined amplitude threshold within a predetermined frequency range.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of devices and / or methods in accordance with embodiments of this invention are now described, by way of example, and with reference to the accompanying drawings, in which:

Figure 1 shows a top view of an agricultural vehicle carrying a header;

Figure 2 shows a cross-sectional view of the header;

Figure 3 shows the torque swing in the time domain;

Figure 4 shows the torque swing in the frequency domain; and

Figure 5 illustrates the steps of the method according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

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Figure 1 shows a top view of a front part of an agricultural vehicle 1. The figure shows a part of the main part 2 of the vehicle 1. The main part 2 of the agricultural vehicle Î contains threshing and / or crop processing mechanisms which are known according to the state of the art. technique and are therefore not further described in this description. An operator cabin 3 is arranged at a front end of main part 2. Via the operator cabin 3, an operator can see the ground surface in front of the vehicle 1, to steer the agricultural vehicle 1 in the correct direction. From the operator's cabin 3, the operator can further visually control and monitor the operation of the header 5. Header 5 is connected to a front end of the agricultural vehicle 1, with a feed system 4. The feed system extends between the header 5 and the main body 2 of the agricultural vehicle 1 to transport crop material from the header 5 to the main body 2.

The header 5 includes a series of row units 6 positioned along a front end of the header 5. In Figure 1, reference number 7 refers to individual row units. Hoods 8 are fitted between adjacent row units 7. The hoods 8 protrude forward from the header 5 and are suitable for guiding crop in a field to an entrance of the row units 7. At the rear end of the series of row units 6, a jack 9 is provided to laterally transport crop material to a central part of the header 5, where the header 5 opens into the feed system 4 so that the crop material passes through the header 5 to the main part 2 of the header. vehicle can be transported.

The parts of a row unit 7 are described with reference to Figure 2.

Figure 2 shows a cross section of the header 5. Figure 2 shows the hood 8 at a front end of the header 5. The row units are arranged next to the hood 8. Each row unit 7 includes a feed / gripping unit 10 which forms an upper part of the row unit, and a chopping unit 11 which forms a lower part of the row unit 7. The feeding / gripping unit 10 includes three main elements consisting of a pair of stem rollers 12, a pair of gathering chains 13 and a pair of stripper plates 14. During operation, when the header 5 is moved across a field, the feeding / gripping unit processes crop stems through the crop stems to be grabbed at a front end of the feeding / gripping unit 10 by means of the pair of collection chains 13. The pair of collection chains 13 prevents the stems from being drifted apart or moving away from the row unit 7. The stem is then further gripped between the pair

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BE2016 / 5791 Stem Rollers, while the Stem Rollers rotate so that the Stem is pulled down by a pair of Stem Rollers. Above the stalk rollers, a pair of stripper plates 14 is spaced so that the stalk and leaves of the crop can pass through the pair of stripper plates, while the heads of the crop material, for example, the corncobs, are prevented from passing through the stripper plates. This allows the feeding / gripping unit to separate the stems and remnants of the heads from the crop material. Such feeding / gripping unit and its operating principles are known, and are therefore not described in further detail.

The moving elements 12, 13, 14 of the feed / gripping unit 10 are preferably connected to a first power transmission shaft 16 which extends along the width of the header 5. Each feed / gripper unit 10 of the row unit 6 series is connected to this first power transmission shaft 16 to be driven by this shaft 16. As a result, the operating speeds of all the feed / gripper units 10 of the row unit 6 series are the same.

The chopping unit 11 includes one or more chopping knives 15. The chopping knives 15 are arranged to protrude at least partially, preferably just below at least a portion of the pair of stem rollers 12. The chopping knives 15 are arranged to cut the stems into small pieces when the stems are pulled down between the pair of stem rollers. It goes without saying that other elements, such as leaves, are also cut into smaller pieces by the chopping knives 15. The chopping units 11 of the row of row units 6 are connected to a second power transmission shaft 16 extending across the width of the header 5. The second power transmission shaft 17 is separated from the first power transmission shaft 16. The second power transmission shaft 17 is driven independently of the first power transmission shaft 16. Chopping units 11 are driven at the same operating speeds via the second power transmission shaft. The operating speed of the chopping units is controllable independently of the operating speed of the feed / gripping units, since they are connected to different power transmission shafts 22, 16. As described above, such separation allows for significant operational improvements.

For safety reasons, each chopping unit 11 is connected to the second power transmission shaft 17 via a safety clutch 22. For example, the safety clutch 22 is mounted on the second power transmission shaft 17. This means that replacing such a clutch 22 would require the full second

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BE2016 / 5791 power transmission shaft 17, which should extend along the essentially full width of the header, should be disassembled. Thus, a protection mechanism, described below, is provided so that an early clutch slip clutch can be detected by the vehicle operator.

From the operator's cab, only the top part of the header 5 is controllable with the naked eye. The operation of the chopping unit cannot be seen from the operator's cabin, since they are located at the bottom of the header 5. Therefore, the slip coupling of a safety coupling and its direct effects by the operator cannot be seen from the operator cabin 3. Slip clutch slippage can only be detected without additional signaling mechanisms when uncut stems arrive at the rear end of the vehicle. When this happens, clutch 22 has been slipping for a while, so there is a high probability that clutch 22 is permanently damaged and needs to be replaced,

With reference to Figure 1, the driving mechanisms for driving the first power transmission shaft 16 and the second power transmission shaft 17 are further described. The second power transmission shaft 17 is connected via a drivetrain 18 to a drive 19 on the agricultural vehicle 1. The first power transmission shaft 16 is connected via a further drivetrain 20 to a second drive of the agricultural vehicle 1. The drivelines 18 and 20 extend between a respective drive on the agricultural vehicle and one side of the header 5, where it is connected to the power transmission shaft. Figure 1 shows an example where the second power transmission shaft 17 is connected to the drivetrain 18 on the right side of the header 5, while the further drivetrain 20 is connected to the first power transmission shaft 16 on the left of the header 5. It will Those skilled in the art will appreciate that this arrangement can also be reversed, or that a series of drivelines can be connected to the corresponding power transmission shafts from the same side of the header 5. Each drivetrain 18, 20 preferably includes one or more shafts, connectors, gear boxes, chains , gears and other elements for transmitting a rotation of the agricultural vehicle drive 19,21 to the power transmission shaft 17, 16 on the header 5.

The invention is based on the recognition that the slipping of a safety clutch 22 connected to the second power transmission shaft 17 is a

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BE2016 / 5791 has an effect on the torque fluctuation. The torque is transmitted from the drive 19 to the agricultural vehicle, via the drivetrain 18, to the second power transmission shaft 17. The second power transmission shaft 17 is connected via the series of safety clutches 22 to the series of chopping units 11 of the series of driving units 6. In this regard, tests demonstrated that the change in torque fluctuation resulting from slipping of one of the safety clutches 22 can be felt essentially in the entire drive mechanism. This relieves the manufacturer of the need to place a slip detection sensor on each of the safety clutches 22 and allows one or several "central" sensors to be fitted in the drive mechanism to detect the change in torque fluctuation.

Figure 1 illustrates how a torque sensor 29 is mounted on the drive 19 and in different positions of the drive train 18. It will be apparent to a person skilled in the art that the options for mounting such a torque sensor are not limited to the illustrated positions. Moreover, it will also be clear that the one or the set of displayed sensors can be selected, and that it is not necessary to have all the displayed sensors. As an alternative, additional sensors 29 can be added. The torque sensor can be designed as a load sensor, as described above, since the load is directly proportional to the torque. A person skilled in the art will understand that a torque can be measured in several ways, and can choose an appropriate one depending on the situation to arrive at the claimed invention.

Figure 3 illustrates a torque swing 23 over time. The horizontal axis is the time axis while the vertical axis represents the torque. In the first segment of Figure 3, the header operates under normal conditions. This first segment is denoted with reference number 24. A torque fluctuation is shown during this normal operation 24, and is shown in curve in Figure 4 in the frequency domain

27. Figure 3 shows a second segment 25 showing the torque fluctuation when one of the clutches 2,2 slips. The difference between the torque fluctuation, of Figure 3, between normal operation 24 and during slip of a safety clutch 25 is significant. Figure 4 shows the swing in a safety clutch with reference number 28. The figure shows that the swing amplitude in many frequency ranges is significantly higher compared to normal operation 27.

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BE2016 / 5791 for completeness Figure 3 further shows a segment 26 corresponding to the stopped operation.

Based on these Figures 3 and 4, those skilled in the art will immediately understand and be able to design electrical, electronic and / or digital tools to detect the slip coupling of a safety coupling based on the torque measurement.

Figure 5 illustrates the steps of the method of detecting and guiding the slip coupling of a safety clutch. Step SI illustrates driving the agricultural vehicle. When driving the agricultural vehicle forward! in step 1, the feed / gripping units indicated by step S2 can be driven.

Step S2 herein comprises driving the second drive 21 so that the first power transmission shaft 16 is driven via the next part of the drive train or to drive the elements of the feed / gripping unit. In step S3, the chopping units are driven. The driving of the chopping units S3 therefore consists of the following steps, starting with the drive 19, so that the second power transmission shaft 17 is started via the drive line 18. This second power transmission shaft 17 is connected to the chopping units 11 via respective safety couplings 22, so that the chopping units are driven.

The feed gripping units, which were driven in step S2, can be visually controlled from the operator's cabin. The chopping units, driven in step S3, are not visible to an operator in the operator cabin. Thus, the method further includes measuring a torque fluctuation in step S4. The torque fluctuation can be measured via the torque or load sensors 29. The torque / load sensors measure a torque fluctuation, as shown in Figure 3.

In step S5, the torque fluctuation is analyzed. Analyzing the torque fluctuation S5 would, for example every second, consist in periodically converting the torque fluctuation in the time domain to the frequency domain as shown in Figure 4. One skilled in the art will understand that other torque fluctuation analyzes can be done, for example, to provide a predetermined characteristic of the fluctuation signal, in step C the torque fluctuation is compared to recognize a change in torque fluctuation. In the example of Figure 5, the comparison is made between the torque fluctuation signal analyzed in step S5 and a predetermined change of reference data D. This predetermined change of reference data may contain an amplitude threshold for a given frequency range. Other more advanced

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BE2016 / 5791 reference mechanisms can be used to detect a change in the torque fluctuation.

If the comparison step does not recognize a change (NO), the measurement of the torque fluctuation is continued as in step 4. In this regard, it is noted that steps S4, S5 and the comparison step C can be applied in a continuous or periodic manner. If the comparison step yields a difference (YES), the method proceeds to step S6 where the slip of a safety link is signaled via a user interface. Preferably, the user interface is available to the operator, for example integrated into the operator's cab, so that slipping a safety clutch signaling S6 immediately informs the operator that a safety clutch is slipping. The operator can respond to this alert based on his knowledge and experience to prevent damage to the slip clutch.

On the basis of the figures and the description, the skilled person will be able to understand the operation and advantages of the invention as well as the different embodiments thereof. It should be noted, however, that the description and Figures are only for the purpose of understanding the invention. and not to limit the invention to certain embodiments or examples used herein. Therefore, it is emphasized that the scope of the invention will only be defined in the claims.

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Claims (11)

CONCLUSIONS: An agricultural vehicle (1) with a header (5) containing a series of row units (6) in the width direction of the header, each row unit of the series of row units including a feed / grab unit (10) and a chopping unit (11), the header comprising a first power transmission shaft (16) extending along the series of row units to drive the feeder gripping unit (10) of the series of row units, the header comprising a second power transmission shaft (17) via a drivetrain (18) connected to a drive (19) of the agricultural vehicle, each cutting unit (11) containing a safety coupling (22) and connected by the safety clutch (22) with the second power transmission shaft (17), and at least one torque sensor (29) is fitted to one of the following elements: the second power transmission shaft (17), the drivetrain (18) and the drive (19), the torque sensor (29) is operationally connected to a torque swing monitoring device, whereby a predetermined change in torque swing can be recognized, indicating a safety clutch (22) is slipping, this torque swing monitoring device being operationally connected with a user interface to avoid slipping a safety clutch. Agricultural vehicle according to claim 1, wherein the torque sensor (29) contains at least one load sensor. Agricultural vehicle according to claim 2, wherein the at least one load sensor is attached to at least one of two elements, ni. the power transmission shaft (17) and the drivetrain (18). Agricultural vehicle according to one or more of the preceding claims, wherein the torque swing monitoring device is capable of measuring an amplitude of the torque swing in at least one frequency range, and wherein the torque swing monitoring device is capable of recognize the change by an amplitude deviation over time in at least one frequency range. 53389 BE2016 / 5791 Agricultural vehicle according to claim 4, wherein an amplitude threshold is set for at least one frequency range, and wherein the torque fluctuation monitoring device is able to recognize the change when the amplitude in the range exceeds the threshold. Agricultural vehicle according to the preceding claim, wherein the first power transmission shaft (16) is connected via a further drive train (20) to a second drive (21) of the agricultural vehicle. A method for detecting the slip of a safety clutch (22) between a chopper (i î) and a row unit (7) of a cutterbar (5) of an agricultural vehicle (1), the method comprising: driving (S3) the shredder via the safety clutch through a power transmission shaft (17) which can be a drivetrain (18) is connected to a drive (19); measuring (S4) a couple in at least one of three elements: ni. the power transmission shaft (17), the drivetrain (18) and the drive (19): detecting (C) a predetermined change of the torque swing (23) indicating the slip of a safety clutch (22); and reporting (S6) the detected slip of a safety clutch (2,2) via a user interface. The method of claim 7, wherein the torque is measured by measuring a load via. at least one load sensor attached to at least one of the two elements, ni. the power transmission shaft (18) and the drivetrain (19) is attached, The method of claim 7 or 8, wherein the torque is measured by measuring a torque oscillation amplitude in at least one frequency range. The method of claim 9, wherein detecting a predetermined change of the torque fluctuation consists of recognizing a predetermined deviation in the amplitude of the torque fluctuation in at least one frequency range. 53389 BE2016 / 5791 The method according to claim 10, wherein the recognition of a predetermined deviation consists of detecting the exceeding of a predetermined amplitude threshold. 53389 be2016 / 5791 53389 be2016 / 5791 53389 be2016 / 5791 ON <4 cn < Nm CN CN CO m on rncn o m CN N3 On CM -CM CM CN CO CN cm o X - on ^ - £ 5 O ON co on CO O' Nt O 'on o NO m cm CN on cm co CM on NJ * on CM o cm CN \ O CN CM cm co o ON NJ * o CM o O ON n0 o O' CN O '\ £> <o co co CM <r; • nt CO o co ^x CN O ^x co NC \ £> r ~ N3 Vj '' S. 53389 be2016 / 5791 O' Ln! Nm co o O A (Mm) 53389 be2016 / 5791 53389 BE2016 / 5791