GB2055533A - Centrifugal fertiliser spreader - Google Patents

Abstract

The spreader has at least one spreader device (5) drivable about a vertical axis (9). A crop depresser device (17) is arranged below the discharge edges of the or each spreader device (5) and comprises a rigid frame (21) with lateral extension members (28) which can be folded in and a broad-area flexible depresser element (22) mounted on the frame. <IMAGE>

Description

SPECIFICATION Centrifugal fertiliser spreader The invention relates to a centrifugal fertiliser spreader and is more particularly concerned with a spreader having at least one spreader device which is rotatable about a vertical axis and which has slide faces from discharge edges of which fertiliser particles are upwardly and outwardly ejected at an acute discharge angle to the horizontal.

Such a centrifugal fertiliser spreader is already known from German Patent Specification No. 2428 538. In this machine the spreader device comprises a centrifugal disc provided with a plurality of th rower scoops, the slide faces of which define at their discharge edges a discharge angle of 45" to the horizontal. Thus, a maximum possible working width of the machine can be attained.

However, a discharge angle of such magnitude results in the disadvantage that the trajectories of the fertiliser particles thrown off by the spreader device are exposed to the effects of wind to a considerably higher degree than with smaller discharge angles with which, in a manner not disclosed in this document, the same working width is obtainable under certain circumstances by increasing the speed of rotation of the spreader device. Furthermore, this centrifugal fertiliser spreader has the disadvantage that in spite of the large discharge angle of its spreader device it cannot be used for late season fertilisation, since in this case the fertiliser particles thrown off by the spreader device impinge against the high, already grown plants in the ascending part of their trajectory.Hence, not only is the working width of the centrifugal fertiliser spreader considerably reduced, but, moreover, considerable accumulations of fertiliser result therefrom on the two lateral edges of the work path, whereas non-fertilised strips are produced between the work paths. It is not possible to compensate for these spreading irregularities even by a subsequent travel with a smaller lateral spacing and this leads to a considerably reduced yield.

The invention provides a centrifugal fertiliser spreader comprising at least one spreader device drivable about a vertical axis and having slide faces, for fertiliser particles, which at their discharge edges define an upwardly and outwardly extending acute discharge angle, and a depresser device below the discharge edges of the or each spreader device, the depresser device extending outwardly from the or each spreader device over the entire spreading range thereof to such an extent that the lateral edges of the depresser device are located at a distance from the axis of rotation of the or the nearest spreader device, which distance is at least three times that of the maximum lateral spacing between the discharge edges of the or the nearest spreader device and its axis of rotation, whereas in the spreading direction which extends parallel to the intended direction of travel of the spreader, the depresser device has an in use length from the axis of rotation of the or each spreader device which length is at least twice the distance of the discharge edges of the or each spreader device in the same spreading direction from its axis of rotation.

Hence, the plant parts which project upwardly beyond the spreader device(s), are held down by the depresser device during travel to such an extent that the fertiliser particles thrown off by the spreader device(s) can fly over them in the ascending part of their trajectories and impinge on them obliquely from above only in the descending part of their trajectories. It is immaterial in this case whether the scatter devices comprise centrifugal discs provided with thrower scoops as in the known centrifugal fertiliser spreader described above, or spreader nozzles driven in a reciprocatory swinging manner.

Since the working width of the spreader is also dependent upon the height ofthe spreader device(s) above the area to be covered which, in the case of late season fertilisation, is formed by the upper parts of the plants, a certain reduction of the working width ofthe machine results in comparison with the fertilisation of a soil surface with no plant growth or covered with only young plants. However, the spreading uniformity remains maintained in this case, so it is possible to compensate for these reductions by correspondingly closer adjacent travel. If the spreader is constructed as an attachment machine for a tractor, this compensation may alternatively be effected to a large extent by raising the spreader within the scope of the possibilities offered by the power lift of the tractor.

However, in order to permit the spreader to be employed, using the path travel method, also for all fertilising operations with a constant working width, the invention provides in a preferred embodiment that the discharge angle of the or each spreader device at the discharge edge(s) thereof is variable in a manner known per se over the entire spreading range by a respective equal amount. It is immaterial in this case whether the change of the discharge angle is effected by an interchange of the spreader device in accordance with U.S. Patent Specification 33 94 892, or by pivotal displacement of slide faces of the spreader device known from British Patent Specification 4325 for obliquely downwardly directed discharge angles.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings, wherein: Figure 1 is a plan view of one embodiment of a centrifugal fertiliser spreader according to the invention; and Figure 2 is a side view on an enlarged scale of the spreader shown in Figure 1 in use.

Referring to the drawings the centrifugal fertiliser spreader shown therein comprises a frame 1, and a storage container 2. The spreader is mounted on to the power lift of a tractor in a known manner not illustrated. Below the storage container 2, two spreader devices 5 are arranged symmetrically in relation to a centre line 4 which extends through the spreader in the intended direction of travel 3. Each spreader device comprises a centrifugal disc 7 provided with thrower scoop 6 and is driven by the take-off shaft of the tractor by way of an angle drive 8. The two spreader devices 5 are driven in mutually opposite directions about the respective axes of rotation 9.A guide screen 10 is attached to the frame 1 in front of the spreader device 5, so that fertiliser particles which issue from the storage container 2 through outlet openings 11 (the size of which is adjustable) to the spreader device 5, are thrown off over the spreading range, characterised by the double arrow 12, by means of the thrower scoops 6.

As illustrated in Figure 2, each thrower scoop 6 consists of an inner part 13 which is fixed to a respective thrower disc 7, and an outer part 14 which is connected to the part 13 for pivotal movement in a vertical plane. Hence, slide faces 15 of the spreader devices 5 may be adjusted to provide at their discharged edges 16an upwardly and outwardly extending discharge angle varying between a of 10 and350.

Below the discharge edges 16 of the spreader devices 5, there is located a depresser device 17 which is arranged on the frame 1 for pivotal movement about an axis 18, which extends transversely to the direction of travel 3, and is supported by an upper member 19 of an attachment coupling 20, rigidly fixed to the frame. The depresser device 17 includes a frame 21 which has a width B of 3 m transversely to the direction of travel 3. A depresser element 22 which is of a broad-area construction and which is formed of flexible material is arranged on the rear side of the frame 21 and extends over nearly the entire width B of the frame 21.In this case, each lateral edge 23 of the depresser device 17 is located in front of the axis of rotation 9 of the respective spreader device 5 which is located nearest to the edge and which is spaced therefrom by a distance E equal to seven times the lateral spacing A of the discharge edges 16 of the respective spreader device 5 from its axis of rotation 9. The depresser element 22 adopts a working position in relation to grown plants 24 in accordance with the illustration in Figure 2, and in this position the depresser device 17 extends in a spreading direction 25 parallel to the direction if travel 3 with a length Lfrom the axes of rotation 9 of the spreader device 5.The length L is nearly four times the spacing A' extending in the same spreading direction 25, between the discharge edges 16 of the spreader devices and their respective axes of rotation 9.

As clearly shown in Figure 2, the fertiliser particles thrown off by the spreader devices 5 may fly unimpededly over the grown up plants 24 in the ascending part of their trajectory 26 even at the flat discharge angle cry of 100. In the case of plants which have grown even higher the outer parts 14 ofthe thrower scoops 6 must merely by adjusted to a correspondingly greater discharge angle '. In this case the extent of the depresser device 17 in the spreading direction 25 may be smaller than transversely to the direction of travel 3 for the reason that the plant 24 held down by the depresser element 22 can erect again only at an extended distance G behind the rear edge 27 of the depresser element 22.Moreover, owing to the fact that the depresser element 22 is formed of flexible material, the plants are treated in a careful manner during tra ei thereover.

For the purpose of improving the manner of working of the depresser device 17 in the case of plants 24 which have grown even higher, extension members 28 are arranged on both sides of the frame 21 for pivotal movement about respective vertical axes 29.

In the working position illustrated by full lines in Figure 1, these extension members 28 project on both sides beyond the width B of the frame 21 and are resiliently held against the abutments 31 in this position by resilient elements 30. This arrangement is advantageous also in respect of the fact that the extension members 28 cannot be damaged if they abut against obstacles during travel.

Additionally, a respective hook 32 is pivotally arranged on the abutments 31. As illustrated by broken lines in Figure 1 on the right-hand side of the depresser device 17, the extension members 28 may be retained in a position 28' by means of these hooks 32 against the tension of the resilient elements 30, in which position they do not project laterally beyond the width B of the frame 21. Such an arrangement is advantageous in order that the centrifugal fertiliser spreader may be driven on public roads and paths even with the depresser device 17, at present a total width of 3 mis prescribed for agricultural working machines for such roads and paths.

Claims (8)

1. A centrifugal fertiliser spreader comprising at least one spreader device drivable about a vertical axis and having slide faces, forfertiliser particles, which at their discharge edges define an upwardly and outwardly extending acute discharge angle, and a depresser device below the discharge edges of the or each spreader device, the depresser device extending outwardly from the or each spreader device over the entire spreading range thereof to such an extent that the lateral edges of the depresser device are located at a distance from the axis of rotation of the or the nearest spreader device, which distance is at least three times that of the maximum lateral spacing between the discharge edges of the or the nearest spreader device and its axis of rotation, whereas in the spreading direction which extends parallel to the intended direction of travel of the spreader, the depresser device has an in use length from the axis of rotation of the or each spreader device which length is at least twice the distance of the discharge edges of the or each spreader device in the same spreading direction from its axis of rotation.

2. A centrifugal fertiliser spreader as claimed in claim 1, wherein the depresser device comprises a rigid frame which extends only slightly beyond the spreader device or devices in the spreading direction extending parallel to the direction of travel, and a depresser element arranged on the rear side of the frame, the depresser element being of broad-area construction and extending over or substantially over the width of the frame.

3. A centrifugal fertiliser spreader as claimed in claim 2, wherein the depresser element is formed of flexible material.

4. A centrifugal fertiliser spreader as claimed in any one of the preceding claims, wherein an extension member is connected to each lateral side of the depresser device for pivotal movement about a ver tical axis, and resilient means are provided for biassing each extension member to a laterally projecting position, in which position each extension member abuts against an abutment.

5. A centrifugal fertiliser spreader as claimed in claim 4, when dependent on claim 2, wherein the frame has a width which is not greater than the maximum permissible width for the traffic of agricultural work machines on public roads and paths, and the extension members are retainable in a position which does not exceed this maximum permissible width.

6. A centrifugal fertiliser spreader as claimed in anyone of the preceding claims, wherein the depresser device is mounted for rotation about an axis which extends transversely to the intended direction of travel, and is supported buy a member which is rigidly connected to the spreader.

7. A centrifugal fertiliser spreader as claimed in anyone of the preceding claims, wherein the discharge angle of the or each spreader device at the discharge edge(s) thereof is variable in a manner known per se over the entire spreading range by a respective equal amount.

8. A centrifugal fertiliser spreader substantially as hereinbefore described with reference to and as shown in the accompanying drawing.