BE1019497A5 - DEVICE FOR DISTINGUISHING A FOREIGN BODY HAVING PENETRATING IN A HARVESTING MACHINE. - Google Patents

Abstract

A device for detecting a foreign body which has possibly entered a harvesting machine comprises a vibration detector (68), which is assigned to a transport roller (30) with a rotating cylinder shell (40). to a shaft (58), and an evaluation device (70) connected to the vibration detector (68), which is adapted to give a signal when the signals from the vibration detector (68) indicate the presence of 'a foreign body striking against the transport roller (30). The vibration sensor (68) is vibration-transmitting connection to the shaft (58) and is responsive to the axis of rotation of the transport roller (30).

Description

DESCRIPTION

Device for detecting a foreign body having entered a harvesting machine

A device for detecting a foreign body having penetrated a harvesting machine with: a vibration detector, which is assigned to a transport roller with a rotating cylinder casing with respect to a shaft, and a an evaluation device connected to the vibration detector, which is designed to give a signal when the signals of the vibration detector indicate the presence of a foreign body striking the transport roller.

State of the art

For agricultural harvesting machines, the danger exists of picking up annoying foreign bodies. This applies in particular when the crop is taken directly from the soil, for example when a swath is collected using a pick-up or a cutting device is guided at low cutting height above the ground.

In order to avoid damage to the harvesting machine, detection devices are known for such foreign bodies, which detect the ferromagnetic properties of the foreign bodies (see EP 0 702 248 A2), but are insensitive to non-foreign bodies. ferromagnetic.

US 4,353,199 A shows a stone detector with a piezoelectric vibration detector which is mounted to the inner wall of a transport roller. As the transport roller rotates, expensive measurements are required for the transmission of the rotary vibration detector signal to the stationary processing electronics, which are embodied in the illustrated embodiment using a pair of coils, one of these rotating with the transport roller and the other being stationary.

In addition, it has been proposed to mount a microphone inside a pre-pressing roll before a chopper, which is connected to a highlighting device and detects the noise picked up by the microphone during striking a stone or other foreign body with the pre-pressing roll and, if necessary, triggering a quick stop of the prior press rolls (US Pat. No. 5,092,818 A). The microphone comprises a membrane extending axially from the axis of rotation of the pre-pressing roll and horizontally or vertically and is therefore exclusively responsive radially to the axis of rotation of the pre-pressing roll. For this reason, the microphone also collects a large number of other noises, for example motor noises, noises generated by the progress of the harvest and noises that are caused by the movement of the upper press roller, pressed downwards by springs, when harvest rates vary. This results in a relatively poor signal-to-noise gain of the microphone signal, so that the chances of success for reliable detection of stones and other foreign bodies are poor.

Goal

It is considered that the problem underlying the invention is to provide a device for the sound detection of foreign bodies in a harvesting machine which is improved vis-à-vis the state of the art.

Solution

This problem is solved according to the invention by the teaching of claim 1, the other claims providing features which advantageously improve the solution.

A device for detecting foreign bodies having possibly penetrated a harvesting machine comprises a vibration detector and an evaluation device connected thereto. The vibration detector is connected transmitting the vibrations to a shaft, in front of which is rotatably mounted a cylinder casing of a transport roller (driven or freewheeling). The vibration detector is responsive in the direction of the axis of rotation of the transport roller, i.e. it detects vibrations and oscillations which propagate axially of the transport roller. Due to the vibration transmitting connection between the shaft and the vibration detector, it is obtained that vibrations generated by a foreign body striking the transport roller are transmitted via the bearings of the transport roller to the shaft and from there to vibration detector. It is therefore used here that the vibrations in building elements propagate rather in the form of longitudinal waves than of transverse waves from a given diameter-length ratio of a medium transmitting them (here: the cylinder shell and shaft). These longitudinal waves are measured by the vibration detector. The sensitivity characteristic of the vibration detector may be such that it is exclusively or at least mainly sensitive in the direction of the axis of rotation of the transport roller. The evaluation device gives a warning signal when the signals of the vibration detector indicate the presence of a foreign body knocking against the transport roller.

The present invention therefore takes advantage of the vibrations propagating in the axial direction of the axis of rotation of the transport roller for the detection of possible foreign bodies. These vibrations have a much better signal-to-noise gain than the vibrations shown by the state of the art (US Pat. No. 5,092,818 A), which propagate radially of the axis of the transport roller, so that safe detection even of non-ferromagnetic foreign bodies becomes possible.

The vibration detector may be attached within the transport roller to the shaft thereof or to a bearing support on which the transport roller is supported, or at the periphery thereof.

The present invention is suitable for any harvesting machinery for which the collected crop is transported by means of a transport roll. Examples are forage harvesters, balers and combine harvesters. The signal output of the evaluation device is preferably connected to a fast stop device for stopping an input conveyor of the harvesting machine, so as to avoid damage to the machine. in the case of an introduced foreign body highlighted by a timely shutdown of the input conveyor. It is also avoided that the harvest delivered by the harvesting machine is contaminated by the foreign body.

Example of realization

The drawings represent an exemplary embodiment of the invention described in more detail below. The drawings show: FIG. 1, a side view and a schematic representation of a harvesting machine with a device according to the invention, FIG. 2, an exploded representation of a transport roller and a vibration detector, and Figure 3 is a schematic top view of the transport roller, the vibration detector and an evaluation device.

A harvesting machine 10 shown in Figure 1 of the self-propelled pick-up type is mounted on a frame 12, which is supported by front and rear wheels 14 and 16. The control of the harvesting machine 10 is from a cab of 18, from which we can see a harvest collection device 20 in the form of a collector. The crop collected on the soil by means of the crop collection device 20, for example grass or the like, is fed to a chopping drum 22 equipped with chopping knives 48, which chops it into small pieces and the The harvest leaves the harvesting machine 10 to a trailer traveling beside it via a rotary extraction well 26. Between the chopper 22 and the transport device 24 is a secondary chopping device 28, through which the crop to be transported is brought tangentially to the transport device 24.

Between the crop collection device 20 and the chopper drum 22, the crop is transported by an infeed conveyor with lower transport rollers 30, 32 and upper transport rollers 34, 36, which are mounted to the conveyor belt. The transport rollers 30 to 36 are also referred to as pre-pressing rollers, since the upper transport rollers 34, 36 are pressed by the spring force against the lower transport rollers 30. 32, so that the crop is precompressed between the transport rollers 30-36 and can be more easily cut. The chopping knives 48 distributed around the periphery of the chopper drum 22 cooperate with a counter knife 38 for chopping the crop.

FIG. 2 shows an exploded representation of the lower front conveyor roll 30. It comprises a cylinder casing 40 of circular section, on the periphery of which are distributed axially extendable drivers 42. At the end faces, the cylinder casing 40 is provided with radial support discs 44. The support disc 44 shown at right in Fig. 2 may be connected at its center to a circular flange 46 with bolts. The flange 46 is rigidly connected to a central shaft 54, which is thus rotatably coupled to the corresponding cylinder casing 40. The shaft 54 in turn is supported to rotate in a bearing support. The shaft 54 (and thus the transport roller 30) can be rotated via a suitable drive (not shown) by its profiled end face on the outside of the carrier. bearing 56. A flange 52 drawn on the left in FIG. 2 is screwed to the adjacent support disc 44 (not visible) and provided with a rotating central bearing 88. A shaft 58 disposed in the interior space of the cylinder casing 40 extends through the bearing of the flange 52 and a left bearing support 56. The shaft 58 does not rotate with the transport roller 30. The shaft 58 is supported at its right end in a bearing 60 in a manner permitting rotation relative to the shaft 54 and to the flange 46. In the shaft 58 is provided at the left end an axial bore which opens into a slot 62 to bring a cable 64 through the shaft 58 inside the cylinder casing 40.

Approximately in the middle of the shaft 58 is fixed a housing 66 which houses a vibration detector 68 (see Figure 3).

FIG. 3 shows a schematic top view of the vibration detector 68 and the corresponding evaluation device 70. The vibration detector 68 attached to the shaft 58 comprises a mass 74, which is attached to a piezoelectric crystal 76 made as an oscillator of thickness, which is itself attached to a support 78, which is in turn fixed to the shaft 58. The cable 64 is attached to a front surface of the piezoelectric crystal 76, while its other end surface is connected via the support 78 and the shaft 58 to the frame 12, that is to say is grounded. When the shaft 58 and the vibration-transmitting support 78 thereof are accelerated in the axial direction of the transport roller 30, the piezoelectric crystal 76 is also accelerated, while the mass 74 remains stationary first because of its inertia and starts moving only slowly due to the elasticity of the piezoelectric crystal 76. The relative movement between the support 78 and the mass 74 leads to a variation in thickness of the piezoelectric crystal 76, which generates a voltage at its outer surfaces, which is present between the cable 64 and the frame 12 and is highlighted. In the embodiment shown, the vibration detector 68 essentially or only measures the axially propagating vibrations of the transport roller 30, the pressure sensitive axis of the piezoelectric crystal 76 and the axially extending mass of the The sensitive direction of the vibration detector 68 therefore extends axially to the transport roller 30.

The vibration detector 68 is reproduced only schematically in FIG. 3. In practice, it is possible to use a commercially available vibration or acceleration or oscillation detector which operates for example with the aid of FIG. a piezoelectric crystal, as shown, or capacitively or inductively. It will be further noted that the vibration detection unit 68 could also be mounted outside the transport roller 30, for example on one of the bearing supports 56 at another location of the harvesting machine 10, sufficiently close to the bearings 60, 88.

The evaluation device 70, which could also be integrated in the housing 66, comprises an amplifier 80 and a signal conditioner, which may for example comprise a band-pass filter 82 and a threshold value switch 84. The output 92 of FIG. threshold value switch 84 is connected to a controller 86, which, when a stop signal is transmitted by the threshold value switch 84, stops driving the transport rollers 30 to 36 with a very high speed. low delay. This can be done by means of a pawl, which serves to mechanically lock the drive of the transport rollers 30 to 36, or by cutting or reversing the direction of flow of the hydraulic flow through a hydraulic motor driving the transport rollers 30 to 36, as described in DE 10 2008 040 357 A1, the publication of which is incorporated by reference herein.

Instead of the bandpass filter 82 and the threshold value switch 84, any other signal conditioner can be used, which can operate in the time range (for example using a bandpass filter) or in the frequency range (for example using a Fast Fourier Transform, FFT) and purely analog or (after digitization) purely numerically.

The mode of operation of the device shown for the detection of foreign bodies having possibly penetrated into the harvesting machine 10 is based on the fact that stones or other foreign bodies striking the transport roller 30 or other foreign bodies as the case may be generate during the collision mechanical vibrations that propagate to the support 78 via the cylinder casing 40, the support discs 44, the flanges 46 and 52, the bearings 60 and 88, the shaft 58 and the casing 66 The vibrations are detected by the vibration detector 68 and amplified by the amplifier 80. The band-pass filter 82 essentially passes only the frequencies that occur during the impact with foreign bodies. The threshold value switch 84, which may have an adjustable sensitivity by the operator via a display and input device 90, responds when a foreign object has been highlighted and then gives a stop signal to the device. 86. The axial direction of the detection of the vibration detector 68 gives a better discrimination capacity than the known radial direction of detection of the control device 86 and a piece of information to the operator via the display and insertion device 90. The state of the art.

Claims (3)

1. Apparatus for detecting a foreign body having entered a harvesting machine (10), with: a vibration detector (68), which is assigned to a transport roll (30) with a cylinder shell ( 40) to a shaft (58), and an evaluation device (70) connected to the vibration detector (68), which is arranged to give a signal when the vibration detector signals (68) ) indicate the presence of a foreign object striking against the transport roller (30), wherein the vibration detector (68) is connected transmitting the vibrations of the shaft (58) and is responsive to the axis of rotation of the transport roller (30), characterized in that the vibration detector (68) is exclusively responsive to the axis of rotation of the transport roller (30). 2. Device according to claim 1, characterized in that the vibration detector (68) is fixed inside the transport roller (30) to its shaft (58) or to the periphery of a bearing support ( 56), on which the transport roller (30) is supported. Harvesting machine (10), in particular a forage harvester, with a device according to one of the preceding claims, whose signal output (92) is connected to a fast shutdown device for stopping a conveyor. input (30 to 36) of the harvesting machine (10).