Conveyor with a metal detecting device

The invention relates to a conveyor with a metal detection device for detecting metal parts in a product to be conveyed, particularly in a crop, with a magnet assembly for generating a measuring magnetic field through which the material to be conveyed is moved, with a sensor assembly of a change measuring magnetic field registered and a Signalauswerteinrichtung which evaluates a change in a magnetic field output from the sensor array signal for detecting a metal part in the product to be conveyed. In addition, the invention relates to a harvester, which has such a conveyor, and a corresponding method for detecting metal parts in a product to be conveyed.

Conveyor of the type mentioned with metal detection device are usually in harvesters, in particular in self-propelled harvesting machines such as forage harvesters, used to possibly jointly penetrated with the crop in the machine metal body -.. Eg a Wenderzinken, a fence post, to detect and disable the machine automatically in this case - a can or a nail. Such a conveyor is known from US-A-5,901,534. This is to prevent that the metal parts cause damage to the machine or be added later during feeding of the crop of the animals and may cause serious injury or even death of animals. In a typical configuration, there is such a conveyor of one or more successive feed roller pairs. Crop, which comes from a header unit of the harvester is drawn in between the rolls and, for example, conveyed to a chopper drum or another working unit. The metal detection device is usually mounted in a fixed within one of the front feed rollers. The coverage of the metal detection device is formed by a signal generated by the magnet arrangement measuring magnetic field. The measured magnetic field is preferably often aligned approximately vertically from below into the crop stream or obliquely forward toward the header unit. The measured magnetic field's been chosen on the strength that it at least pervades much of the crop material layer. The magnet assembly usually consists of a plurality of transversely arranged crop flow direction to the permanent magnet.

Where a metal part, wherein there is a ferromagnetic type impurity element, in this detection area, the magnetic field is partially reinforced. This magnetic field change is recorded by the sensor array. The sensor assembly usually has in this case a plurality of sensor elements. In general, these are to coils, in which the change in the measuring magnetic field, a signal is induced. In principle, however, other magnetic field sensors such as Hall sensors, usable. The signal output from the sensor array is then fed to a Signalauswerteinrichtung which evaluates the signal to see if the change in magnetic field caused by a piece of metal to be conveyed. In this evaluation, the signal is amplified, for example, optionally digitized, filtered and set a threshold. When the set threshold value is exceeded, for. Example, an output signal is generated which then a quick stop device for an entire machine or the feeder unit, that is forwarded to the conveyor. Within a very short time before the metal part of a conveyor downstream operating unit - for example, when the forage harvester cutterhead - has reached, the machine and the conveyor is stopped. Once the machine is stopped, the operator has to leave the conveyor running in the ejection direction and the crop eject again and browse to remove the metal part. This prevents damage to the following working units and contamination of the crop will be effectively prevented by metal parts.

The installation position of the metal detection device requires however disorders that can lead to false triggers of metal detection device. The metal detector is indeed arranged protected within the feed roller against damage and wear, however, are located in the detection area of ​​moving parts that can lead to a change of the detection behavior and nuisance tripping. So z. B. is the outer surface of the feed roller profiled and influences the magnetic field. Further, the upper of the feed rollers, for example, mounted vertically movable and adjusts its distance from the lower feed roller to the crop on. This movement leads to an influence of the magnetic field. To reduce this maximum design influence can the adjacent areas non-ferromagnetic materials such as VA-steel or plastics are used in the detection area and. An example of this is described in DE 199 12 407 A1. Other factors that can lead to false triggering of the metal detection device, external magnetic fields, for example, the Earth's magnetic field or magnetic fields from extending in the ground power cables etc.

If the harvesting operation interrupted by false alarms frequently unnecessary, this inevitably leads to increase harvesting costs. In addition, right trigger will accordingly erroneously interpreted by the operator faster than faulty trigger per se and can by re-activating the feeder without scanning the crop but then still lead to damage of the working equipment. Too frequent spurious tripping therefore abate the reliability of the metal detection device. Although the number of false triggers can be reduced by an intelligent signal evaluation with signal filter and said threshold. However, if the threshold of the metal detector set very high in order to avoid false triggers, the risk is increased that metal parts fall undetected into the machine. Especially small metal parts, traversing the entire machine without trouble, then not discovered and ultimately contaminate the crop. Consequently, however, the adjustment of the threshold of the signal evaluation of the metal detector is always a compromise between possible nuisance tripping and possible damage to the machine or a contamination of the crop by undetected metal parts.

It is therefore an object of the present invention, a conveyor and a method of the type mentioned further develop that will reduce the number of false alarms, without the detection reliability is reduced.

This object is achieved by a conveyor according to claim 1 and by a method according to claim 12th

According to the invention the conveyor is therefore equipped with an interference sensor device which, when a registration of a fault event that a nic leads evoked ht by metal parts in the product to be conveyed, registered by the sensor arrangement of the metal detection device magnetic field changes, outputs a faulty trigger warning. Ie. The idea is a timely recognition of fault events by means of an additional interference sensor device, so that these disruptive events can be considered accordingly.

The interference sensor device can be designed in various ways. It is only essential that possible disruptive events certainly be measured by this interference sensor device, which ultimately lead to a registration of changes in magnetic field at the sensor device of the metal detecting device. Ie. It can be made directly magnetic field changes are measured as well as other events that lead indirectly to the fact that the magnetic field sensor device changes "sees".

In a preferred embodiment, the interference sensor device, for example, includes a magnetic field sensor. By means of this magnetic field sensor are directly, ie immediately, magnetic field changes registered, as measured in the sensor arrangement of the metal detection device itself. However, the magnetic field sensor is constructed and / or arranged such that only he such magnetic field variations registered, which are not caused by metal parts in the product to be conveyed that way.

Particularly preferably, the magnetic field sensor can adapted and / or arranged such that only changes of external magnetic fields, for example, changes in the earth's magnetic field or magnetic fields caused by power lines in the ground, can be registered. This can be achieved for example by an arrangement in which the field lines of the generated by the magnet assembly of metal detection device measuring magnetic field substantially on a first side of the metal detection device by the over-funded Good. In a conventional arrangement of the metal detection device in the lower front feed drum of a conveyor, these are preferably the top of the metal detection device. The sensor assembly of metal detection device is then placed in this measuring magnetic field. When using coils as the sensor elements, these are, for example, arranged so that the field lines of the measuring magnetic field passing through the coil is substantially. This can, for example, with the aid of suitable pole pieces formed within the coil, and a suitable arrangement of the coils are secured to the individual magnets of the magnet assembly. The Magnetfeldstörsensoreinrichtung is then placed on a measuring the magnetic field opposite side, for example, the underside of the metal detection device and thus is substantially outside this measuring magnetic field, ie at most in the edge region of the measuring magnetic field. The magnetic field sensor of the interference sensor device may moreover be a sensor similar or the same type as in the sensor elements of the sensor arrangement of the metal detection device itself.

By appropriate arrangement ensures that the metal parts are registered within the crop, which alter the measured magnetic field of the sensor arrangement of the metal detection device immediately. Since the magnetic field sensor of the interference sensor device, however, is not within the measuring magnetic field or only in passing the measuring magnetic field, these changes of the measuring magnetic field from the magnetic field sensor of the interference sensor device does not or can not be registered with the necessary intensity. In this case, accordingly sends the metal detection device properly a signal without the interference sensor device outputs an erroneous triggering warning signal. contrast Should changes of external magnetic fields on, for example, when the harvester moves over an objective in the ground power cable, this external magnetic field superimposed on the measured magnetic field. Thus, a magnetic field change is registered by the sensor means of the metal detection device. At the same time this external magnetic field but is also registered by the magnetic field sensor of the interference sensor device. In this case, consequently, are not only the sensor arrangement of the metal detection device outputs a signal but also the interference sensor device is a false triggering warning signal. Thus it is clear that this is a false triggering in the triggering of the sensor arrangement of the metal detection device.

In a very simple and cost-effective implementation of this embodiment, located on one of the conveyed past Good side facing away from the magnet assembly metal wall has the metal detection device, which collects the magnetic field line of the measuring magnetic field and passes toward the magnet assembly. Metal detection devices currently commonly used in harvesting machines generally have anyway located such on the bottom, often referred to as "Magnet tub" Marked metal wall. The magnetic field sensor of the interference sensor device is then on the side facing away from the magnet assembly side of this metal wall, that is, for example, arranged below the magnetic pan.

In a further embodiment, the interference sensor device has, in addition or alternatively to an acceleration sensor. Such an acceleration sensor is used to register occurring at the sensor arrangement of the metal detection device acceleration forces as disruptive events. Even such events can in fact lead to a change in magnetic field to the sensor assembly. It may for example by Bodenunebeneinheiten, z. B. when driving through potholes, come to strong vibrations of the vehicle, whereby the magnetic field etc. changes occur due to the bearing play or compounds of the feeder housing. Likewise, it should be noted that even registered with such shocks, can cause rapid Erdmagnetfeldveränderungen to false tripping.

In a particularly preferred embodiment, the interference sensor device along a direction transverse to a direction of crop flow to a plurality of spaced sensors at different positions. It may be similar or different sensor types. For example, could be arranged at the axial ends of a feed roller two magnetic field sensors, as especially common near the roller flanges disorders. Furthermore, could for example be arranged in the middle region of the feed roller, an acceleration sensor. The signals from the various sensors of the interference sensor device can then be processed and, if necessary, a false triggering warning signal to be output.

The faulty triggering warning signal of the interference sensor device can be used in various ways. For example, are output to the signal evaluating the faulty triggering warning signal. In this case, the signal evaluation device to be designed such that false triggering using the warning signal, a signal outputted from the sensor arrangement of the metal detection device signal is corrected. Specifically, for example magnetic field changes that are not caused by Störmetall, be subtracted from the signal. Likewise, the metal detection device, in particular the signal evaluation, also be designed such that upon receipt of a faulty triggering warning signal the metal detection device or the signal evaluation is temporarily totally disabled or possibly even just the sensitivity of the metal detection device or the signal evaluation - for example, by changing the threshold - temporarily is reduced. In a certain predetermined time period can then the metal detector will be reactivated and will return to the normal sensitivity.

Furthermore, the faulty triggering warning signal can also be output directly to the emergency stop device, so that there the rapid stop is in receipt of a stop signal to the metal detection device, which is received in a subsequent, specific short period after failing triggering warning signal is suppressed.

Alternatively or additionally, the faulty triggering warning signal can also be output directly to the machine operator. This especially makes sense when a fault event is registered only after the faulty timer and the time is no longer sufficient to suppress false triggering, for example in the signal evaluation or in the emergency stop device. In this case, the operator is informed that it is false triggering, so that it can start again without the wait and without first having to search through the crop. For this purpose, the interference sensor device has according to a signal output device in the cab - which may be a part of a normal operator interface of the machine, for example, a conventional display, etc. - to be on another controller, etc., directly or indirectly, for example.

The invention is explained in more detail below with reference to the accompanying drawings with reference to embodiments. Show it:<ul><li>Figure 1 is a schematic diagram of a forage harvester with an embodiment of a conveyor according to the invention,</li><li>2 is a block diagram illustrating the sensor array and the signal evaluation of a metal detection device, </li><li>Figure 3 shows a cross section through a metal detection device with an additional interference sensor device,</li><li>Figure 4 is an axial plan view of a feed roller of a conveyor according to the representation of the position of the metal detection device. Figure 3 in the conveyor,</li><li>5 shows a longitudinal section through the feed roller of Figure 4 along section line AB.</li></ul>

When the harvester 1 shown schematically in Figure 1 is a typical forage harvester. In the direction of the front of the forage harvester 1 a harvesting attachment device 3 is arranged, here, for example, a maize header for harvesting a corn field. By means of a cutting unit (not shown) of the attachment device 3, the corn plants cut at a certain height above the ground and then conveyed into the machine. 1

located directly behind the harvesting attachment device 3 in the forage harvester 1 a conveyor 6, consisting of two in the conveying direction R successively arranged feed roller pairs 7, 8, 9, 10. The two front feed rollers 7 and 10 also serve for pre-pressing of the crop G. They are therefore often also referred to as compression rollers 7, 10th The crop G is then behind the second pair of feed rollers 8, passed 9 toward a chopping unit 2, in which the crop is chopped and accelerated G and possibly then to a post-acceleration upwards via a chute to a pulled by the harvester trailer or alongside moving transport vehicle is ejected.

To avoid that metal parts with the crop can get into the engine and cause damage to the machine 1 itself or contamination of the crop, is located inside the conveyor 6, here in the front lower feed roller 10, a metal detection device 18. Once in the metal detecting means 18 is a metal part in the crop G will be recognized, this outputs a signal which leads to an immediate stop of the machine.

The metal detection device 18 is working on this with a measuring magnetic field M which is oriented upward in the crop material flow (Figure 3), so that the crop G this measuring magnetic field passes through M. Metallic elements lead to a change of the measuring magnetic field M, which are recognized by the metal detection device 18th A possible concrete structure of such a metal detection device 18 is explained below with reference to Figures 2 to 5, where 3 is a mechanical structure, and Figure 2 shows a circuitry construction. Figures 4 and 5 show the arrangement of this concrete structure within the feed roller 10th

A centerpiece of the metal detection device 18 is a magnet assembly 19 which consists of several in a row transversely to the direction R of the crop G juxtaposed individual magnets each here. with its north pole upwards and its south pole S to exhibit below. Alternatively can be used instead of a number of individual permanent magnets and a long, continuous magnetic. This magnet assembly 19 is located on a metal wall 25, also magnetic pan 25 hereinafter, which also over the entire width transversely to the direction R of the crop G extends (Figure 5).

On the upper side of the magnet assembly 19 has several pole shoes 20. These each have a lower wide portion, which rests on the north pole side of the magnet assembly 19, and an upper narrow portion. The upper portions of the pole pieces 20 each protrude into individual coils 21₁, ..., 21_8th (Figure 2) into it. These coils 21₁, ..., 21_8th form the sensor assembly 21 to register changes in the measuring magnetic field M. Overall, these are eight single pole shoes 20 with eight different coils 21₁, ..., 21_8thTransversely to the conveying direction R cover with their detection areas a, b, c, d, e, f, g the entire width. This is shown schematically in FIG. 2 The eight coils 21₁, ..., 21_8th are each, to double-coil with two windings, but of the first and last coil 21₁, 21_8th Only one winding is used.

As shown in Figure 3, the magnetic field lines extend ML of measuring magnetic field M from the north pole of the magnet assembly 19 by the individual pole shoes 20 - and thus through the coil 21₁, ..., 21_8th the sensor device 21 - at the top by the crop G and back via the magnetic pan 25 to the south pole S of the magnet arrangement 19. A change in the measuring magnetic field M by metal parts in the crop G will consequently mean that the coils 21₁, ..., 21_8thIn whose detection area a, b, c, d, e, f, g, the measurement magnetic field change occurs, a current is induced, which can then be tapped as signal S and evaluated.

It is understood that the magnet assembly 19, the pole shoes 20, the coils 21₁, ..., 21_8th the sensor assembly 21 and the magnet trough 25 as tightly as possible to each other must be connected to another magnetic field fluctuations caused by changes in the relative position of these components, such as vibration of the harvester 1, etc., should be avoided. Serve this purpose brackets 23, the coils 21₁, ..., 21_8th keep up with the magnet assembly 19 and the pole pieces 20 thereon to the magnet tub 25th In addition, the entire structure is encapsulated in a potting compound 24 and thus largely protected against damage in harsh harvesting operation. The magnetic pan 25 itself is arranged on a rigid supporting axle 11 within the lower feed roller 10th The precise location and position will be explained later with reference to FIGS. 4 and 5

The signal evaluation of the individual signals S of the coil 21₁, ..., 21_8th the sensor assembly 21 is carried in a signal evaluation 30. This can be directly in the metal detection device 18, for example, arranged between the lower part of the pole pieces 20 and the coils of the sensor arrangement 21 board 22 may be disposed (Figure 3). But it can also be outside of the metal detection device 18, located for example in a processor of a control device of the machine. 1 Basic principle, it is also possible that parts of Signalauswerteinrichtung 30, for example, preamplifier o. Ä., On the board 22 in the metal detection device 18 and other parts of the evaluation device 30 externally in a separate unit within the harvester 1, especially in the central control device of the machine 1 are housed.

. To avoid that, for example produced by the movement of the roll shell or by the earth's magnetic field, uniformly occurring magnetic field changes that affect the entire width of the indentation, lead to erroneous triggering the metal detection device 18, are - as shown in Figure 2 - the individual coils 21₁, ..., 21_8th the sensor assembly 21 each designed as a double coil. In this case, two windings of adjacent coils 21₁, ..., 21_8th oppositely connected to the inputs of a common differential amplifier 31st From the edge of coil 21₁, 21_8th is used here only one of the existing windings.

This formwork causes interference that all the coils 21₁, ..., 21_8th relate to, for example, a uniform magnetic field change over the entire width of the feed unit, in all the coils 21₁, ..., 21_8th are equally registered. The induced currents then rise in the differential amplification on each other, so that such events are not registered. on the other hand occurs on a change in magnetic field only in a part of the individual detection areas a, ..., g, then this means that only part of the coils 21₁, ..., 21_8th a current is induced, whereby at some of the adjacent coils 21₁, ..., 21_8th different strong currents are induced. This produces a difference signal which is amplified in the amplifiers 31st

The output signals AS of the amplifier 31 are forwarded to analog / digital converter 32, in each of which a threshold is adjustable. Only when the analog input signal AS exceeds this adjustable threshold, the analog / digital converter 32 is a digital output signal DS output, which is then passed to an evaluation processor 33 at the output. This is the output side of a stop signal SS to a corresponding quick-stop circuit 34 of the machine, when a digital input signal DS occurs on one of the analog / digital converters 32 connected inputs. The quick-stop circuit 34 then provides for an immediate halt of the conveyor 6 or the entire harvesting machine. 1

A problem with a conventional metal detecting means then occurs when it only in the detection areas a, ..., g at a portion of the coils 21₁, ..., 21_8th comes to a magnetic field change, but caused by external influences, ie not through metal parts in the crop G. In this case, there is a false tripping of the metal detection device. A typical interference event could, for example, driving through an external magnetic field to be that the measured magnetic field is superimposed on, but only to a part of the individual coils 21₁, ..., 21_8th the sensor arrangement 21 acts. Likewise, such a disruptive event be driving through a pothole, so that on one side of the conveyor 6 is moved jerkily. Such a strong acceleration of the coils 21₁, ..., 21_8th the sensor arrangement 21 in the earth's magnetic field also results that in the coils 21₁, ..., 21_8th different strong currents are induced, which can lead to a false tripping total.

To avoid such false alarms, the conveyor 6 comprises an additional interference sensor device according to the invention 26. These registered especially those disruptive events that are not caused by a metal parts in the crop G may result registered by the sensor arrangement 21 magnetic field change, and then outputs a faulty triggering warning signal F out. This faulty triggering warning signal F is transmitted, for example, to the Auswertprozessor 33 (see Figure 2), where it leads to the fact that the output of a stop signal SS is suppressed in a certain period subsequent to the rapid stop circuit 34th Alternatively, this false triggering signal F directly to the analog / digital converter 32 are output to there raise the adjustable threshold, so that the signal evaluation 30 and thus the entire metal detection device 18 is less sensitive. Preferably, it is ensured that after a period of a few seconds, the adjustable threshold is lowered automatically.

The detailed design and the location of the interference sensor device 26 is shown in Figures 3, 4 and 5. FIG.

Figure 4 shows in axial view, the arrangement of the magnetic pan 25 with the therein magnet assembly 19, the pole pieces 20, the sensor arrangement 21, etc. within the lower front feed roller 10 of the conveyor and 5 shows a view of the arrangement from the front in the conveying direction considered.

As can be seen from Figure 5, the pickup roller 10 from two end disk-shaped roller flanges 12a, 12b. On the left in Figure 5 illustrated first roller flange 12a down outwardly extending shaft 15 is fixed, which is rotatably mounted in the machine and which serves as a drive shaft. The second roller flange 12b is mounted on a rigid axle 11 by means of a bearing 16, through which extends through the entire roller 10 and its end is mounted rotatably in a recess in the shaft 15 connected to the first roller flange 12a. Here, the drive shaft 15 and the rigid axle 11 are arranged coaxially with each other. The two roller flanges 12a and 12b are respectively connected via a plurality of angled, parallel to the roller axis 11 extending rolled sections 14 with each other. These rolled sections 14 are evenly distributed along the periphery of the roller 10 and thus form a closed jacket surface with a blade-like profiling, to pull the crop G in the desired manner between the roller pairs 7, 10, 8, 9 through the conveyor. 6 The exact shape of the profile can be best seen in FIG. 4 The individual production profiles 14 are in this case the ends connected by screws 13 to the roller flanges 12a, 12b.

On the rigid axle 11 within the rotating feed roller 10 is the magnetic pan 25 with the therein other components such as magnet assembly 19, pole pieces 20 and the sensor elements, ie the coils 21₁, ..., 21_8thAttached. The shaft 11 is hollow, at least in the area of ​​the bearing 16, ie it has a serving as carrying 17 hole through which the cables are routed for tapping the signals S of the metal detection device 18 and the sensor arrangement 21 from the roller 10th

Specifically, the interference sensor device 26 in the illustrated embodiment comprises two perturbation coils 27, each of which has inside a pole piece 28th This perturbation coils 27 are executed in the present embodiment in the same way as the coils 21₁, ..., 21_8th the sensor assembly 21 of the metal detection device 18. However, there are the perturbation coils 27 respectively below the magnetic pan 25. As a result, it is ensured that the perturbation coils 27 are arranged substantially outside the measuring magnetic field M. In addition, the perturbation coils 27 opposite to the sensor coils 21₁, ..., 21_8th the sensor assembly 21 down. The arrangement is here specifically so that the perturbation coils 27 are inclined forward.

Once a change in magnetic field due to an external magnetic field occurs, this is registered by the relevant disturbance coil 27, in the detection region the magnetic field changes. It is just like in the top side to the array 21 of metal detection device 18 belonging coil current 21₁, ..., 21_8th induced. This can then be used directly as a fault triggering warning signal. However, it is also possible for the signals of the individual perturbation coils 27 a first Störsensorauswerteschaltung 35 (shown schematically in Figure 5) to supply that first evaluates the interference signals and then, if necessary, outputs an erroneous triggering warning signal F.

In addition, the interference sensor device 26 in the illustrated embodiment, even in the middle region of the feed roller 10 an acceleration sensor 29 (Figure 5), the output signal is also supplied to the Störsensorauswerteeinrichtung 35th The special arrangement of the various sensors 27, 29 of the interference sensor device 26 can be determined in many cases, not only that a fault event is present, but possibly also of the nature of this interference event. If, for example by a jerky acceleration of the magnetic field sensors 27 of the interference sensor device a magnetic field change on, for example, due to passage driving over a pothole, this event is also measured by the acceleration sensor 29, so that is a total clear that this impact event has led to the change in magnetic field. Are other hand, only one of the two magnetic field sensors 27 outputs a signal without the accelerometer responds 29, this indicates that, in addition, an external magnetic field occurs. Likewise be determined by the different magnetic field sensors 27, whether a disruptive event in the right or the left side of the pickup roller 10 or over the entire width is registered.

The faulty triggering warning signal F may preferably be designed such that it also contains information on the respective error or the fault event. In this case, the faulty triggering warning signal F, for example, within the evaluation processor 33 of the signal evaluation unit 30 are also used to make a comparison with the from the sensors 21₁, ..., 21_8th the sensor assembly 21 of the metal detection device 18 signals outputted perform S, so as to increase the detection reliability even further. In particular, it can be checked whether the output signal S of the sensor assembly 21 of the metal detection device 18, which indicates a metal part in the product to be conveyed G, from the same region comes as the faulty triggering warning signal F, ie whether these two signals are really correlated or whether coincidentally both institutions fires together.

The faulty triggering warning signal F can in the illustrated Äusführungsbeispiel incidentally also additionally or alternatively - for example, if a prevention of erroneous stop signal SS for reasons of time is no longer possible - the signal evaluation 30 directly via an audible and / or visual display means 5 which in itself cab 4 the harvesting machine is located, are output to the driver. Based on the there issued false triggering warning signal F, the driver recognizes immediately that a previously successful fast stop the harvester 1 is due to a faulty triggering of the metal detection device 18 and the harvester 1 can start again without first retracted crop G eject again and search.

It is finally pointed out once again that the above-described specific embodiment of a conveyor according to the invention is merely one embodiment which may be modified by the skilled person in many different ways without departing from the scope of the invention. In particular, the interference sensor device can also be realized with only a single Störsensor or with a considerably higher number of Störsensoren. Likewise, a wide variety of different Störsensoren can be used, such as coils with or without integrated pole piece, or even a separate measuring sensors with magnetic field, ie, it is used as a Störsensor form of a separate metal detector. Likewise, Hall sensors for measuring magnetic fields and any desired acceleration and speed measuring devices can be used. Furthermore, the specific location of the individual sensors can each needs to be adjusted. As often occurs in the field of roller flanges 12a, 12b to nuisance tripping are preferred positioned at least at these ends of the roller respectively corresponding sensors. If only one sensor is to be used, it has proven to be particularly preferred to arrange these on the transmission side (drive side) within the feed roller 10th Furthermore, the invention is not limited to the specific form of such conveyor. Incidentally, can also be implemented in a different form on the conveyor, in particular in one of the other feed rollers when using such a conveyor with a plurality of feed rollers, the metal detection device and / or the interference sensor device.

LIST OF REFERENCE NUMBERS

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