GB2299010A - Forage harvester - Google Patents

Abstract

A forage harvester for agricultural crop material such as for example corn, grass and the like, comprising a rotatingly drivable main cutter drum 2, at least one axis-parallel pair of pre-pressing rollers 4, 5 substantially comprising an upper and a lower pre-pressing roller which have toothed conveyor bars and which are drivable in opposite directions and reversingly, and a metal detector 8 associated with the pair of pre-pressing rollers, wherein at least the upper pre-pressing roller of the pair can be fitted with beater bars (10)(Fig.3) whose beater edges extend rectilinearly and flat. This reduces the risk of foreign metal bodies being conveyed towards the cutter drum over the top of the upper roller when such bodies are detected and the rollers are reversed.

Description

Forage harvester The invention concerns a forage harvester for agricultural crop material such as for example corn, grass and the like, having a rotatingly drivable main cutter drun, an axis-parallel pair of front ancillary rollers, substantially comprising qyzei and lower pre- pressing rollers which can be fitted with toothed conveyor bars and which are drivable in opposite directions and reversibly, and a metal detector associated with the pair of pre-pressing rollers.

In the forage harvester in question the pair of pre-pressing rollers, as considered in the direction of movement of the crop material through the forage harvester, is disposed in front of the main cutter drun, The crop material is fed to the pair of pre-pressing rollers by means of a font ancillary unit which is equipped with a transverse conveyor screw. In the normal situation, a further pair of pressing rollers and possibly also a condor roller are disposed between the main cutter drun and the pair of pre-pressing rollers. A stationary co-operating blade is associated with the main cutter drum.

The metal detector which is normally arranged stationarily is intended to detect magnetic material in the crop material and to trigger off a signal in order abruptly to stop the entire cutter assembly so that the rollers or other components do not suffer damage. The toothed conveyor bars which extend over the entire width of the pre-pressing rollers are disposed inclinedly relative to the main body of the prepressing rollers, more specifically in such a way that in the normal direction of rotation, that is to say in the cutting operation, the free ends of the conveyor bar, which ends are remote fran the axis of rotation, trail.When the cutting assembly is stopped by a signal fran the metal detector, the pre-pressing rollers are then driven in the opposite direction to the normal direction of rotation in order to convey the crop material back again. When that happens, the foreign piece of metal can then be rsved.

Particularly when dealing with short-stalk agricultural crops such as for exanple grass it is inevitable that the crop material is entrained in the direction of rotation by the upper pre-pressing roller and is thrown in a direction towards the main cutter dnm. That is to be attributed to the inclined positioning of the conveyor bars which in that case are at 'grip'. If the foreign metal body is in the entrained crop material, it cannot be found and thus still passes in a roundabout way into the subsequent conveyor device or even into the cutter drun, which inevitably results more or less in destruction thereof.

The present invention is based on the problem of so designing a forage harvester of the kind described in greater detail in the opening part of this specification as to ensure in a structurally simple manner that, in the direction of rotation of the pre-pressing rollers of the pair thereof in the opposite direction to the normal direction of rotation, the crop material is conveyed exclusively towards the front ancillary assembly. The specified problem is solved in that at least the upper pre-pressing roller of the pair of prepressing rollers which is the first pair in the direction of flow of material can be fitted with beater bars whose beater edges extend rectilinearly and flat.

The smooth-surfaced beater bars now ensure that, in the direction of rotation of the pre-pressing rollers in opposite relationship to the normal direction of rotation, the crop material is transposted exclusively in a direction towards the font ancillary assembly. Those smooth-surfaced beater bars are catpletely sufficient when dealing with short-stalk crop material, for eagle grass. When dealing with long-stalk crop material, for example grain crops, winding or entrainment of crop material by the upper pre-pressing roller is excluded in any case so that when harvesting such crop material the normal toothed conveyor bars can perfectly well be used.The concept of the invention can be carried into effect in different ways. A first possibility provides that the soooth-surfaced beater bars can be releasably fixed to the toothed conveyor bars in such a way that the teeth of the conveyor bars are covered. The smooth-surfaced beater bars are then connected to the toothed conveyor bars when necessary.

That can be effected for example by screw connections. The effect of the teeth of the conveyor bars is thus obviated. In that respect it is particularly advantageous when the smooth-surfaced beater bars are arranged behind the toothed conveyor bars, relative to the direction of rotation in use of the forage harvester. When a foreign body is detected they are then at the front in the direction of travel, in the reversing rotary movement, so that they came into contact with the crop material. That possibility is advantageous whenever forage harvesters which are already in use are to be subsequently fitted, as the toothed conveyor bars are welded to the main body of the rollers.

A second possibility provides that the toothed conveyor bars are releasably fixed to the roller body of the pre-pressing roller or rollers so that the pre-pressing roller or rollers can be selectively fitted with the toothed conveyor bars or with smooth-surfaced beater bars. Depending on the nature of the crop material involved either the toothed conveyor bars or the smooth-surfaced beater bars are used.

The invention is described in greater detail hereinafter with reference to the accompanying db3siings showing a preferred embodiment, in which: Figure 1 is a purely diagrammatic side view of part of the forage harvester according to the invention, Figure 2 is a partial view in longitudinal section of the upper pre-pressing roller of the pair thereof, and Figure 3 is a view in section taken along line III-III in Figure 2.

The forage harvester 1 shown in Figure 1 is equipped with a main cutter drum 2 which is rotatingly drivable about a horizontal axis. The main cutter drun 2 has a fixed co-operating blade 3 associated therewith. As viewed in the direction of movement of the crop material through the harvester, arranged upstra5n of the main cutter drun 2 is a pair of pre-pressing rollers, formed by an upper pre-pressing roller 4 and a lower pre-pressing roller 5. The main cutter drum 2 and the upper pre-pressing roller 4 are drivable in rotation in the anti-clockwise direction in the view shown in Figure 1 in normal operation of the forage harvester.The lower pre-pressing roller 5 is drivable in the opposite direction to the upper prepressing roller 4, that is to say in the clockwise direction. The dimneter of the upper pre-pressing roller 4 is markedly greater than that of the lower pre-pressing roller 5. Both the upper pre-pressing roller 4 and also the lower pre-pressing roller 5 are fitted with toothed conveyor bars 6 and 7 respectively which are disposed at equal angular spacings relative to each other. The toothed conveyor bars 6 of the upper pre-pressing rollers 4 are disposed inclinedly to the respectively applied tangent in such a way that the free tips which are remote fran the axis of rotation trail, with respect to the normal cutting mode of operation. Arranged in the circle of rotation of the lower pre-pressing roller 4 is a stationary metal detector 8 which triggers off an electrical signal if a magnetic foreign body 9 is detected in the crop material which is illustrated by way of irdication. when that signal is triggered off the entire cutting unit is abruptly stopped. Then, at least the upper prfrpressing roller 4 is driven in the opposite direction to the normal direction of rotation, as indicated by the broken-line arrow. Figure 1 shows that, in particular when dealing with short-stalk crop materials such as for exarp?le grasses, the upper pre-pressing roller 4 acts in substance like a winding drum so that crop material is flung by way of the upper pre-pressing roller 4 towards the main cutter drum 2.As illustrated by way of indication, the foreign body can then be entrained and passes into the normal path of conveying movement again, so that it cannot be separated out. That position of the foreign body 9 is identified by reference numeral 9'.

In order to anent the above-indicated events from occurring, as shown in Figures 2 and 3 each toothed conveyor bar 6 of the upper pre-pressing roller 4 is provided with a smooth-surfaced beater bar 10 which in the illustrated embodiment is fixed to the respective toothed conveyor bar 6 by screws 11. In that way the teeth 6a of the toothed conveyor bar 6 are covered over. In the illustrated embodiment the toothed conveyor bars 6 are welded to the roller body. It will be seen fran Figure 1 that entrairrnent of the crop material is prevented in a direction of rotation of the upper pre-pressing roller 4 in the clockwise direction. The beater bars 10 are then at the front in the direction of rotation.As shown in Figure 3 the outer free edges extend in an arcuate configuration in order completely to eliminate the entrainment effect. In contrast to the illustrated construction the toothed conveyor bars 6 may also be releasably fixed to the roller body so that the upper pre-pressing roller 4 can be equipped selectively with the toothed conveyor bars 6 or with the smoothsurfaced beater bars 10. It is also possible for both bars to be fitted into a common holder. The drives and control means for stopping the cutting assembly are not described for the sake of simplicity.

In addition the forage harvester 1 is equipped with a pair of pressing rollers canprising an upper pressing roller 12 and a lower pressing roller 13. The two rollers are disposed between the main cutter drum 2 and the pre-pressing rollers 4 and 5. All rollers are disposed with their axis parallel to the axis of rotation of the main cutter drum 2. So that the spacing between the lower pre-pressing roller 5 and the lower pressing rollers is bridged over to form a conveyor section, an intermediate roller 14 is mounted between the lower pre-pressing roller 5 and the lower pressing roller 13. The main cutter drum is fitted with a plurality of blades 15 which are arranged at equal angular spacings fran each other. As viewed in the direction of nrrvement of the crop material or the material to be cut, through the harvester, disposed downstream of the main cutter drum 2 is a post-crusher device 16 which serves for example to beat the grains of corn. That is followed by a conveyor shaft 17 which is also fitted with a post-acceleration device 18 so that the chaff material is flung upwardly .

Claims (7)

1. A forage harvester for agricultural crop material such as for example corn, grass and the like, comprising a rotatingly drivable main cutter drum, at least one axis-parallel pair of pre-pressing rollers, substantially comprising an upper and a lower pre-pressing roller which have toothed conveyor bars and which are drivable in opposite directions and reversingly, and a metal detector associated with the pair of pre-pressing rollers, wherein at least the upper prepressing roller of the pair can be fitted with beater bars whose beater edges extend rectilinearly and flat.

2. A forage harvester according to claim 1 wherein the beater bars can be releasably fixed to the toothed conveyor bars in such a way that the teeth of the conveyor bars are covered.

3. A forage harvester according to claim 2 wherein, with respect to the direction of rotation in cutting use, the beater bars are arranged downstream of the toothed conveyor bars.

4. A forage harvester according to claim 3 wherein the outer edges of the beater bars, which edges are remote from the axis of rotation of the pre-pressing roller and the toothed conveyor bars, extend in an arc.

5. A forage harvester according to claim 1 wherein the toothed conveyor bars are releasably fixed to the roller body of the upper pre-pressing roller so that the pre-pressing roller can be fitted selectively with the toothed conveyor bars or with the smoothsurfaced beater bars

6. A forage harvester according to any preceding claim, wherein the beater bars are fixed in position.

7. A forage harvester substantially as hereinbefore described with reference to the drawings.