GB2169183A - Cutting unit for a forage-harvester - Google Patents

Abstract

A cutting unit for a forage harvester comprises rotating flails cooperating selectively with either a fixed first counterblade 22 or a second counterblade 27. Counterblade 27 can be pivoted (11) from an inoperative upper position to an operative lower position in which the planar face of counterblade 27 extends tangentially with respect to the path of movement of the cutting tips of the flails. When counterblade 27 is in its operative lower position, it is below the fixed counterblade 22 and cooperates with the flails to chop pre-cut vegetation (Fig. 7). When the counterblade 27 is in its inoperative upper position, counterblade 22 co-operates with the flails to cut standing vegetation (Fig. 6). <IMAGE>

Description

SPECIFICATION Forage-harvesters This invention relates to forage-harvesters.

Flail-forage-harvesters are already known for harvesting greens in root, for example grass, which are to be conserved (ensiled) in a silo or used directly as forage. Another method of conservation is to cut the grass with a mowing machine and let it dry. This dried material cannot, however, be picked up using an ordinary flail-forage-harvester. The known flaii-forage-harvesters deliver the grass in varying lengths. Typically, 10 per cent of the grass is shorter than 50 mm, 20 per cent from 50-100 mm and 70 per cent longer than 100 mm.This is not satisfactory with respect to ensilation of the dried material, since the demand here is that more than 90 per centofthe material isshorterthan 100 mm, and that the greater part of this is in turn about 50 mm in length or shorter.

Various types of forage-harvesters are known which have a pick-up assembly, feed rollers and disc with knives, alternatively a drum with knives, which chop the grass into short lengths with theoretical chopping lengths of from less than 10 mm up to 50 mm, depending on manufacture and setting.

These are complicated, expensive machines that are susceptible to foreign bodies such as stones, for example.

According to the present invention there is provided in or for a forage-harvester a cutting unit for cutting vegetation, comprising a housing, a rotor mounted in the housing for rotation about a horizontal axis, flails attached to said rotor for rotation therewith, the free ends of the flails cooperating with counterblade means operable selectively to provide an effective counterblade (i.e.

a counterblade effective to co-operate with the flails to cut vegetation) in either an upper position for cutting down standing vegetation or a lower position for chopping pre-cut vegetation.

In one arrangement according to the invention said counterblade means comprises a single counterblade movable selectively into said upper and lower positions. In alternative arrangements the counterblade means is provided forward of the rotor and comprises a first counterblade fixed with respect to the housing in said upper position and a second counterblade selectively securable in an operative position below the first counterblade and in an inoperative position.

One embodiment of the invention will now be described in more detail by way of example with reference to the accompanying diagrammatic drawings in which: Figure 1 is a side view of a forage-harvester according to the invention, Figure 2 is a sectional view of the lower front part of the forage-harvester seen from the front when adjusted for use as a flail-forage-harvester, Figure 3 is a section on line A-A of Figure 2, Figure 4 is a similarviewto that of Figure 2 when the forage-harvester is adjusted to gather up and process forage lying on the ground, Figure 5 is a section on line B-B of Figure 4, Figure 6 shows the operating principle when the forage-harvester is used as an ordinary forage harvester, and Figure 7 shows the operating principle when the forage-harvester is used to gather up and process forage lying on the ground.

In the drawings reference numeral 1 designates a rotor-housing with a rotor 2 and associated flails or knives 3. The rotor 2 is driven round by belts which are driven by a belt pulley 4which is in turn driven by the power take off (PTO) of a tractor, not shown on the drawings. When rotor 2 is driven round, the flails 3 will also rotate, and they cut and throw the grass along the first guideplate 5 and up through a discharge duct 6. The forage-harvester is equipped with a groundwheel 7 which maintains the correct spacing between the flails 3 and the ground 8. When harvesting the forage-harvester moves in the direction of the arrow 9, preferably beside the tractor, and throws the grass into a cart or trailer (not shown) which is pulled behind the tractor.

When the forage-harvester is used as an ordinary flail-forage-harvester, as shown in Figures 2 and 3, a bridge 10 on its front edge is swung up about a pair of first axles 11 which are rotatably supported in a socket 12 on each side of the rotor-housing 1. The bridge 10 is supported in the upswung position by two arms 13 which, with the aid of bolts 14, are rotatably fastened to the respective second axle 15 which, at its bottom, is formed into a hook 16. A spiral spring 17 and disc-springs 18 press against a first face 19 on each of the arms 13, whereby arms 13 are held steady against the bridge 10 and lock it, thus preventing the bridge 10 from swinging down.

When the forage-harvester is being driven forward in the direction of the arrow 9, the standing grass 20, Figure 6, enters through an entry gap 21, the flails 3 cut the grass from the ground 8, and further chop the grass against a first counterblade 22. Figures 2 and 3 show two flails 3, though the number will vary depending on the width of the forage-harvester. The forage-harvester can have three rows of flails 3, as shown on Figure 1, but can also have fewer or more numerous rows, though such that the flails 3 together fill the area which in Figures 2 and 4 is delimited by a dot-and-double-dash line 23.

The sum of the widths of the flails 3 is a little longer than the width delimited by the dot-anddouble-dash line 23 in Figures 2 and 4. There is thus an overlap, ensuring that the harvest is cut across the entire width of the forage harvester.

When the forage-harvester is to be used to gather up and process forage which is lying on the ground 8, Figures 4 and 5, the entry gap 21 is reduced by swinging down the bridge 10 on the first axles 11 onto stops against the adjustment devices 24, with the aid of which the distance of the bridge 10 from the flails 3 can be adjusted. The bridge 10 is held against the adjustment devices 24 by hooks 16 on the second axles 15, in that the second axles 15 with hooks 16 extend through long holes in the bridge 10.

The arms 13, which are rotatably attached 14 to the second axles 15, now present a second face 25 towards the disc-springs 18, and these disc-springs 18, due to the eccentric effect of the arms 13, exert such a powerful force against the spiral springs 17, that these are pressed down into their springhousings 26 which are enclosed by sockets 12.The disc-springs 18 now rest on the top of the springhousings 26, and a powerful force acts against the second face 25 of the arms 13, such that the second axles 15 with their hooks 16 are pressed strongly against the bridge 10, holding the bridge 10 against the regulation devices 24, so that the distance between the second counterblade 27 on the bridge 10 and the flails 3 is always correct when the flails 3 pass the bridge 10. is presupposed that this distance is approximately zero to achieve a strong and exact chopping of the grass. The line extending through the centre of the rotor and the leading edge of the second counterblade 27 on the bridge 10 is angularly displaced 38 degrees in relation to a vertical line 28 through the centre of the rotor 2.

To prevent the arms 13 and thus the second axles 15 with hooks 16 from rotating and thus releasing their grip on the bridge 10 and coming loose, the sockets 12 are equipped with lock 29 which prevents the arms 13 from swinging forward.

On Figures 4 and 5, as on Figures 2 and 3, only two flails are shown but any desired number of flails maybe provided.

The operating principle of the forage-harvester when used as an ordinary flail-forage-harvester is shown in Figure 6. The material to be harvested, for example standing grass 20, is forced forward and down. For each rotation made by the rotor 2, each individual flail 3, apart from making one rotation, will also be moved a given distance forward, depending on rotor speed and ground speed. Figure 6 shows schematically some stalks of grass, and of these the first stalks 30 were cut at the root the previous time the flail 3 passed this sector, while the second stalks 31 were cut by the flail 3 which has just passed.

A third stalk 32 has been cut higher up, the cut-off part 33 of the stalks will fall down on the flail 3. The flail 3 will also partially cut the stalks against the forage-harvester's first counterblade 22. When the third stalk 32 is cut at the root atthe next rotation, the stalk will be short. The final result will thus be a mixture of long and shorter stalks which are folded and partially crushed. Crushing takes place in part as the standing grass 20 is cut, and in part between the first counterblade 22 and the flail 3. Because there is a gap of 10-20 mm between the first counterblade 22 and the flail 3, the stalks are only partially chopped here.

The working principle when the forage-harvester is used to gather and process forage which is lying on the ground 8 is shown in Figure 7. The material, for example grass, is presupposed to have been cut at the root by a mowing machine which has left the grass in a swath (windrow) 34 lying on the remaining stubble 35. The bridge 10 of the forageharvester, by means of its angled face 36, will pinch the swath together. The bottom face 37 of the bridge 10 will then, due to the size of its protruding length in the direction of movement of the forage-harvester given by arrow 9, hold the swath 34 such that the flails 3 cannot cast it forward. The friction between the swath 34 and the bottom face 37 of the bridge must not be so large that the swath 34 is pushed forward.The friction can be adjusted by lowering the forage-harvester when the swath 34 is low, and raising it when the swath 34 is high. The flail 3 lifts the swath 34 up against the second counterblade 27 of the bridge. As the flail 3 passes the second counterblade 27 at a distance of approximately zero mm, the swath is chopped, at the same time as it is crushed somewhat. The grass remains lying on the flail 3 as short-chopped stalks 38, after which it is thrown along the second guideplate 39 of the bridge, on along the first guideplate 5 and up through the discharge duct 6. By increasing the revolutions of the rotor 2 in relation to the ground speed of the unit, it is possible to achieve more chops per unit length, and consequently it is possible to vary the length of the short-chopped stalks 38 by adjusting this ratio.

Further chopping can be achieved by equipping the rotor 2 with one or more extra sets of flails 3.

This combined crushing and chopping renders the harvested material suitable for ensilation even if dried. Because the material is crushed more than is the case with previously known forage-harvesters, it will pack down better, and ensilation will therefore give a better result.

A forage-harvester with a cutting unit as illustrated is thus able to be used to cut and load greens growing on root: grass, swede, beets and other agricultural products. It will also be able to pick up and load previously cut and dried materials lying on the ground.

It will be appreciated that the two counterblades and the bridge mechanism described above could be replaced by one counterblade and a mechanism adapted so as to move the single counterblade between the positions occupied by the two counterblades described according to the desired operation of the harvester.

It will also be appreciated that the angular displacement of the line extending through the leading edge of the counterblade 27 and the rotor 2 with respect to the vertical line extending through the rotor of 38 degrees is merely an example. A suitable range of such angular displacements would be in the order of 33 to 43 degrees. Furthermore, the length of the bottom face 27 in the direction of arrow 9 is preferably between 100 and 160 mm.

Claims (14)

1. In or for a forage-harvester a cutting unit for cutting vegetation, comprising a housing, a rotor mounted in the housing for rotation about a horizontal axis, flails attached to said rotor for rotation therewith, the free ends of the flails cooperating with counterblade means operable selectively to provide an effective counterblade in either an upper position for cutting down standing vegetation or a lower position for chopping pre-cut vegetation.

2. A cutting unit as claimed in claim 1, wherein said counterblade means comprises a single counterblade movable selectively into said upper and lower positions.

3. A cutting unit as claimed in claim 1, wherein the counterblade means is provided forward of the rotor and comprises a first counterblade fixed with respect to the housing in said upper position and a second counterblade selectively securable in an operative position below the first counterblade and in an inoperative position.

4. A cutting unit as claimed in claim 3, wherein said second counterblade is mounted on a bridge which is pivotally mounted on the housing about an axis parallel to the axis of rotation of the rotor.

5. A cutting unit as claimed in claim 4, wherein the bridge is formed with a bottom face which projects forward from the second counterblade by a distance of between 100 and 160 mm.

6. A cutting unit as claimed in claim 5, wherein the bridge when in its lower position has a forward face which is angled downward so as to guide the swath under said bottom face.

7. A cutting unit as claimed in any one of claims 3 to 6, wherein the second counterblade in its operative lower position provides a planar surface which is tangential to the path described by the free ends of the rotating flails.

8. A cutting unit as claimed in any one of claims 3 to 7, wherein a plane extending through the axis of the rotor and the leading edge of the second counterblade when the second counterblade is in its operative lower position is angularly displaced by 33 to 43 degrees forward of a vertical plane extending through the axis of the rotor.

9. A cutting unit as claimed in claim 8, wherein said angular displacement is 38 degrees.

10. A cutting unit as claimed in any one of claims 3 to 9, wherein mounting means for said bridge comprises two spaced, spring loaded pins pivotally mounted on a portion of the housing which is parallel to the axis of the rotor, the lower end of each pin being formed with a .hook and the upper end of each pin having hingedly connected thereto a lever arm, the arrangement being such that in one position of the arms the hooks locate the bridge in its lower position with respect to the housing and in another position the arms secure the bridge in its upswung position with respect to the housing.

11. A cutting unit as claimed in claim 10, wherein adjustment devices associated with the said mounting means are provided to alter the lower position of the second counterbladethereby changing the distance between the path of the free ends of the flails and the second counterblade in its operative lower position.

12. A cutting unit as claimed in claim 10 or claim 11, wherein the spring loading of the pins comprises disc springs encircling the pins, which springs permit the bridge to swing forward if a foreign body enters between the second counterblade in its lower position and the flails.

13. A cutting unit as claimed in any one of claims 10 to 12, wherein each arm has a free end in the form of a claw adapted to engage said bottom face of the bridge and the second counterblade when the bridge is in its upswung position.

14. In or for a forage-harvester a cutting unit substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.