GB2048640A - Multi-row potato harvester - Google Patents

Abstract

A multi-row potato harvester comprises a machine frame (1) supported at an adjustable height on wheels and a screen conveyor belt (4) the front part of which is guided in a riddle (3) pivotably mounted on the machine frame (1) about an axis at right angles to the direction of travel and about an axis parallel to the direction of travel of the potato harvester and supported on the ground by means of depth guidance rollers (7). The riddle (3) is fixed to the machine frame (1) by means of a pair of lower guide rods (16, 16') and a single upper guide rod (10). The guide rods are articulated to the front of the machine frame (1) and the riddle (3) and the articulation points (11, 12, 17, 17', 18, 18') are constructed in such a way that they permit pivoting of the riddle at right angles to and in the direction of travel of the potato harvester. <IMAGE>

Description

SPECIFICATION Multi-row potato harvester This invention relates to a multi-row potato harvester having a main frame supported at an adjustable height on wheels and a screen conveyor belt guided in a riddle which is pivotally mounted on the machine frame. Such a potato harvester is for example disclosed in German Offenlegungsschrift No.

2,259,205.

In known potato harvesters, the riddle of the screen conveyor belt is articulated in such a way in an area of the machine frame which is at the rear in the direction oftravel that it is pivotable about an axis in the direction of travel and about an axis at right angles thereto. Thus, the depth guidance rollers and consequently the digging blades can be adapted to the inclination of a slope. Thus, even in the case of multi-row potato harvesters, it is possible to uniformly pass underthe potato plants to be dug.

The machine frame can be horizontally aligned independently of the front part of the screen conveyor belt by adjusting the height of a wheel, so that the dug potatoes are uniformly conveyed over the entire width of the screen conveyor beit, this being important for a completely satisfactory screening of soil and for the removal of weeds which have also been dug up.

However, the known potato harvesters have the disadvantage that the front part of the screen conveyor belt with the digging blades and the depth guidance rollers is pushed in much the same way as a wheelbarrow owing to its rear articulation to the machine frame. Thus, the forces acting on one side tend to rotate the front part of the screen conveyor belt about a vertical axis relative to the machine frame. The more the riddle is pivoted by such forces, the greater the transverse forces which occur. These kinematic conditions lead to very great stressing of the suspension of the riddle on the machine frame, so that it must be given a very robust construction and is prone to faults.

In orderto adaptthe digging blades to the individual potato banks and also to permit a simpler and less loaded mounting of the front part of the screen conveyor belt on the machine frame, German Offenlegungsschrift No. 2,628,730 teaches forming the front part of a screen conveyor belt by three separate, juxtaposed screen conveyor belts in each case associated with one row of potatoes and said belts can oscillate independently of one another about an axis at right angles to the direction of travel. Such a construction is obviously very costly and complicated. Although it permits an adaptation of the individual digging blades to the height ofthe individual banks and reduces the problems of high forces in the articulation, it does not solve the problems resulting from the pushing of the belts.A main disadvantage of this known machine is its susceptibility to faults.

Blockages can easily occur between the rows, because in this area there is no driving by a screen belt.

German Offenlegungsschrift No. 1,582,474 discloses an idea of directly fixing both the machine frame and the screen conveyor belt of a potato harvester to a drawbar connectable with a tractor in such a way that the machine frame and the screen conveyor belt are pulled, but it is possible for the latter to be aligned in accordance with the gradient of the slope independently of the machine frame.

However, the machine described in this prior specification is obviously a very simple single-row potato harvester without any guidance of the screen conveyor belt by depth guidance rollers. Its construction cannot be transferred to multi-row potato harvesters.

The present invention aims to provide a multi-row potato harvester in which the riddle is fixed to the machine frame so as to oscillate about two axes without excessively high forces acting on the riddle attachment when forces act on the riddle from one side.

According to the invention, there is provided a multi-row potato harvester comprising a machine frame supported at an adjustable height on wheels and a screen conveyor belt the front part of which is guided in a riddle pivotably fixed to the machine frame about an axis at right angles to the direction of travel and about an axis parallel to the direction of travel of the potato harvester and supported on the ground by means of depth guidance rollers, wherein the riddle is fixed to the machine frame by means of lower guide rods and an upper guide rod, the guide rods being articulated to the front of the machine frame and the riddle and the articulation points being constructed in such a way that they permit a pivoting of the riddle at right angles to and in the direction oftravel ofthe potato harvester.

The advantages of the invention essentially result from the fact that the riddle is no longer pushed but instead is pulled. It is therefore automatically aligned in a central position in the machine frame. The riddle no longer tends to tilt in the machine frame when forces act on one side and it can therefore no longer oscillate up and down.

Further, according to the invention, the suspension of the riddle takes place in an area of the potato harvester which is not exposed to contamination by soil trickling through the screen conveyor belt.

The pivot axis of the front part of the screen conveyor belt admittedly passes below the belt, but it is only an imaginary axis defined by the position of the guide rods.

According to a preferred embodiment of the invention, two lower guide rods are articulated laterally to the riddle by means of which the riddle can on the one hand perform the desired tilting movement about an axis running in the direction of travel, but on the other hand can be firmly and reliably held in a simple manner. The lower guide rods holding the riddle are arranged in an area exposed to only limited soil contamination.

If, according to a further development of the invention, the articulation points of the lower guide rods are formed by slots on the riddle, the latter can perform the necessary tilting movement by moving up and down in the slots.

It is particularly advantageous to construct the potato harvester in such a way that only a single upper guide rod is provided, which rod is centrally articulated to a transverse support of the riddle and which bridges the latter. The articulation points are preferably spherical. Owing to this construction, a three-point suspension is obtained. As only one upper guide rod is provided, it is sufficient to con struck the articulation points in a spherical manner in orderto permitthe desired tilting movementofthe riddle. In practice, the front articulation points of the lower guide rods can be constructed as simple pivots, because the angular changes of the lower guide rods are very small.

A hydraulic lifting mechanism for raising the riddle is preferably provided between the machine frame and the upper guide rod or at least one of the lower guide rods by means of which mechanism the riddle can easily be raised for driving the potato harvester on a road.

The imaginary pivot axis of the riddle desirably passes through the position of the guide rods below the machine frame in the potato harvester. Owing to the iow position of the pivot axis, there are only minor changes to the angle of action of the digging blades, even in the case of swinging movements of the riddle. The articulation of the riddle according to the invention admittedly provides the possibility of arranging the pivot axis coaxially to the axis of the upper guide pulley, so that the distance between the upper and lower guide pulleys of the screen conveyor belt does not change on pivoting the front part of the said belt. However, greater importance is attached to a substantially constant angle of action of the digging blades.

The angle of action of the digging blades can fundamentally be adjusted in a simple manner by varying the length of the guide rods.

Various constructional possibilities of the invention are possible. One of these is diagrammatically shown in the drawing and is described hereinafter.

The drawing is a perspective view of the front part of a two-row potato harvester according to the invention.

Referring to the drawing, the potato harvester comprises a machine frame 1 supported in a conventional manner (not shown) on the rear end in the direction of travel by two wheels (not shown). On the front end ofthe machine frame 1 is provided a towing device 2 by means of which the potato harvester can be attached to a tractor. Within the frame 1 there is a riddle 3 which can be pivoted about a transverse axis and in which is located a screen conveyor belt 4 guided by lower guide pulleys, one of which is shown at 5. Upper guide pulleys of the screen conveyor belt (not shown) are mounted in the rear part of the potato harvester on the machine frame 1. In general, two or three pulleys are used both for the upper and lower guidance of the belt.

Towards the front, the riddle 3 has digging blades 6. It is supported by means of in each case one depth guidance roller 7 per potato row on the individual banks of potatoes to be dug. Two substantially vertically directed supports 8, 8' are rigidly fixed to the riddle 3 and face one another on the two sides thereof and are interconnected above the screen conveyor belt 4 by a cross-member 9. Between articulation points 11 and 12 an upper guide rod 10 connects the centre of the cross-member 9 to an upwardly directed bracket 13 rigidly fixed at the front to the centre of the machine frame 1.

At the front and laterally on the machine frame 1 are provided two downwardly directed arms 15, 15' to each of which is articulated a lower guide rod 16, 16' at a respective articulation point 17, 17'. The lower guide rods 16, 16' are also fixed to the supports 8, 8' on articulation points 18, 18' below the machine frame 1.

All of the articulation points 11,12,17,17' and 18, 18' are spherical, so that e.g. the lower guide rods 16 can be pivoted clockwise without the lower guides 16, 16' having to perform this movement and there can still be a pivoting of riddle 3 about the longitudinal axis of the potato harvester.

The guide rods 16, 16' and 10 and the position of articulation points 11, 12, 17, 17', 18, 18' are such that the imaginary pivot axis of the riddle 3 passes below the machine frame 1, so that by pivoting the riddle 3 the angle of action of the digging blade 6 varies to the minimum possible extent.

Claims (9)

1. A multi-row potato harvester comprising a machine frame supported at an adjustable height on wheels and a screen conveyor belt the front part of which is guided in a riddle pivotably fixed to the machine frame about an axis at right angles to the direction of travel and about an axis parallel to the direction of travel of the potato harvester and supported on the ground by means of depth guidance rollers, wherein the riddle is fixed to the machine frame by means of lower guide rods and an upper guide rod, the guide rods being articulated to the front of the machine frame and the riddle and the articulation points being constructed in such a way that they permit a pivoting of the riddle at right anglets to and in the direction of travel of the potato harvester.

2. A multi-row potato harvester according to claim 1, wherein two lower guide rods articulated laterally to the riddle are provided.

3. A multi-row potato harvester according to claim 1 or claim 2, wherein the articulation points of the lower guide rods on the riddle are formed by slots.

4. A multi-row potato harvester according to any preceding claim, wherein a single upper guide rod is provided which is centrally articulated to a transverse support of the riddle and which bridges the latter.

5. A multi-row potato harvester according to any preceding claim, wherein the articulation points are spherical.

6. A multi-row potato harvester according to any preceding claim, wherein a hydraulic lifting mechanism for raising the riddle is provided between the machine frame and the upper guide rod or at least one of the lower guide rods.

7. A multi-row potato harvester according to any preceding claim, wherein the imaginary pivot axis of the riddle passes through the position of the guide rods below the machine frame of the potato harves ter.

8. A multi-row potato harvester according to any preceding claim, wherein the length of the guide rods is adjustable.

9. A multi-row potato harvester substantially as described herein with reference to the drawing.