GB2056240A - Apparatus for pulling potato plants - Google Patents

Abstract

An apparatus for pulling potato plants comprises a movable frame (1) which carries at least one set of plant- guiding elements (7), at least one set of plant-pulling elements (8) and at least one travelling wheel (9). The plant-pulling elements are pairs of co- operating, mutually engaging pneumatic tyred wheels (8) caused to revolve with high speeds in opposite directions about vertical or substantially vertical axes. Both the angular position and the circumferential speed of the plant- pulling wheels as well as their operating height are adjustable. Energy for rotation of the wheels may be derived from the power take-off shaft of a tractor. <IMAGE>

Description

SPECIFICATION Apparatus for pulling potato plants The invention relates to apparatus for pulling potato plants, i.e. for mechanically removing plants from potato crops growing in the field.

In the culture of seed potatoes, it is known that several measures have to be taken for preventing an affection of potato tubers by germs. One of these measures is destructing the plants shortly before harvesting the potato tubers. This destruction may be effected by spraying the plants to death with chemicals, or else by pulling the plants off. Spraying to death is a simple, rapid and relatively inexpensive method which is frequently used, but a disadvantage thereof is that a waiting period of 5 or 6 days has to be observed before the tubers can be harvested. In addition, certain fungi may stiil easily penetrate through the stem to the tubers after spraying, and further, the use of chemicals will meet more and more with environmental objections.Contrary thereto, the method of plant-pulling may be used two or three days in advance of tuber harvest and this means that the crops may grow for three days more and may have higher yields. Moreover, the connection between stem and tubers is immediately interrupted during plant-pulling and environmental objections will not be raised. Therefore, the method of plant-pulling is of growing interest today.

Many apparatuses for mechanical pulling of potato plants are known already. In their simplest form, these apparatuses comprise a movable frame having a set of plant-guiding elements, a set of plant-pulling elements and a travelling wheel positioned one after the other in the moving direction of that frame. During use of the apparatus, the frame is moved over a ground area cultivated with potatoes, e.g. by means of an agricultural tractor or in another way, and the travelling wheel will travel on the ground and will ensure the adjustment to height of the plantpulling elements. As soon as the apparatus meets a potato plant during its movement, the leaves and stem of this plant are conducted by the plantguiding elements into the direction of the plantpulling elements, whereupon said elements grip the plant and pull or pluck it off.The plant is then spread onto the ground, optionally after being chopped, and the potato tubers will remain in the ground.

The shape of the plant-pulling elements in these apparatuses may vary considerably, dependent from the question whether the plants are to be pulled in vertical or in horizontal direction. In an existing type of apparatus, the elements comprise a pair of cylindrical or torpedoshaped rollers which have been positioned substantially horizontaily and which are driven for rotation in mutually opposite direction to pull the plants engaged by them in substantially vertical direction from the ground. A disadvantage of this construction is, however, that too many tubers are pulled with the plants from the ground.

In another existing type of apparatus, the plantpulling elements comprise a pair of cooperating, vertically positioned conveyor belts which extend in the moving direction of the apparatus and are driven for movement in counter direction. The potato plants which are conducted to these elements by the plant-guiders, will be gripped from either side by the belts and will be pulled or plucked off in horizontal direction. In this construction, the tubers will mainly remain untouched in the ground, but disadvantages are that the relatively expensive belts wear out rapidly and that the distance from the foremost edge of the plant-pulling elements to the travelling wheel will become relatively large and thereby have a detrimental effect to the adjustment of height.

The invention has for its object to provide an apparatus for pulling potato plants which is relatively simple, will show little wear and nevertheless will work effectively.

According to the invention, this object may be achieved by using as plant-pulling elements a pair of cooperating pneumatic tyre wheels which are rotatable each around a vertical or substantially vertical axis and which are driven in opposite rotational directions by driving means. Such a set of plant-pulling elements will grip the plants firmly and will pull them off in substantially horizontal direction so as to ensure an efficient operation, especially when the pneumatic tyres of each pair of wheels engage each other by forming a large surface of contact. The amount of wear will be much lower than with conveyor belts and a replacement of the relatively unexpensive wheels will not raise any problem. Moreover, these wheels will occupy only little space and this means that they can be mounted close to the travelling wheel and that the adjustment of height will satisfy all demands.

Accordingly, the invention provides an apparatus for pulling potato plants, comprising a movable frame having at least one set of plantguiding elements, at least one set of plant-pulling elements and at least one travelling wheel, said apparatus being characterized in that the set of plant-pulling elements comprises a pair of cooperating pneumatic tyre wheels rotatable around vertical or substantially vertical wheel axes and provided with driving means for rotationally driving the wheels of each wheel pair in opposite directions. Preferably, the wheels of each pair have been mounted close to each other so as to create mutual engagement of the pneumatic tyres of these wheels by means of a large contact surface.

The term "at least" as used here, means that the invented apparatus should at least comprise a combination of a set of plant-guiding elements with a set of plant-pulling elements and a travelling wheel, said combination being useful for treating a single row of potatoes in the field. If desired, however, two or more of such combinations may be present so as to be able to treat two or more rows of potatoes by the apparatus at the same time.

Other objects and features of the invention will appear from the following description of the drawing which shows an embodiment of the invented apparatus by means of example.

Figure 1 shows this embodiment in longitudinal cross-section, going through the center of the apparatus and also indicates its operation.

Figure 2 shows this embodiment in perspective view, some parts having been omitted or broken away for the sake of clarity.

The apparatus of figures 1 and 2 comprises a frame 1 which may be attached to the rear side of an agricultural tractor 5 by means of a three-point suspension (compare the points of connection 2, 3, 4 in figure 2) and which may be moved by this tractor in the direction of arrow A. If desired, the frame 1 may be listed from its operative position (as shown) to a non-operative position, or lowered from such non-operative position to the position as shown, by means of a leaver 6 which may be actuated from the tractor.

Two pairs of plant-guiding elements 7, two pairs of plant-pulling elements 8 and two travelling wheels 9 are carried by frame 1 and positioned one after the other in the direction of movement. Thanks to this double number of parts, the apparatus can be used for simultaneous treatment of two rows of potatoes in the field, but it will be clear, that, if desired, these parts might be present singular, in quadruplicate or the like for the simultaneous treatment of one row or four rows of potatoes.

The plant-guiding elements 7 have been fastened adjustable in height and in lateral direction to the frame 1 by means of telescope bars 10, 11 and fastening screws 12. They have been positioned in pairs so as to be able to engage the plants of a row of potatoes from either side and to guide these plants under slight compression and, if needed, a slight lifting action to the entrance of the plant-pulling elements 8. In the drawing, they are of triangular, open shape and their lower edge 13 is pointing somewhat obiiquely inwards and above, but any other appropriate shape which leads to the same purpose, e.g. the shape of a triangular plate, a torpedo-shaped body, a rotatable disc or wheel, is possible.

The plant-pulling elements have wheels 8, and the rims 14 thereof are surrounded by pneumatic tyres 1 5 of profiled rubber. The wheel axles 16 of these wheels 1-8 are supported for free rotation by tubular axle bearings 1 7 which have been mounted in pairs and in parallel relationship to the lower sides of two pivotable gear boxes 1 8. The axle bearings 1 7 of each pair are in close relationship so as to press the wheels 8 with their pneumatic tyres 1 5 towards each other and to form a large surface of contact. Of course, the pneumatic pressure within the tyres should be such that a compression of the tyres for forming this large contact surface becomes possible.

The gear boxes 1 8 are each mounted pivotably on a horizontal shaft 19 extending cross-wise to the moving direction of the frame. Such shaft 1 9 extends through the whole gear box and is supported by the frame with the aid of bearing blocks 20. This means that, in principle, the tubular axle bearings 1 7 and wheel axles 1 6 are pivotable around the center lines of the shafts 1 9 and may thereby have any desired angular position with regard to the vertical. Adjustment and fixation of this angular position is performed each time by a screw spindle 21 which is pivotably mounted to part 22 of the frame 1 with one of its ends and which projects through an eyelet 23 of an arm 24 rigidly secured to the gear box 1 8 with its other end.The mutual position of eyelet 23 and screw spindle 21 and thereby the angular position of the axle bearings 17 may then be fixed with the said of two nuts 25.

A stationary gear box 26 has been mounted to frame 1 between both pivotable gear boxes 1 8 for driving purposes. This gear box 26 engages the inner ends of shafts 1 9 and further serves as a bearing for a revolvable shaft 27 which projects in forward direction and which may be connected to the power take-off shaft 28 of the agricultural tractor 5. Shaft 27 may drive both shafts 1 9 by means of conical gears 29 and in their turn, these shafts 1 9 may cause the wheel axles 1 6 of wheels 8 to revolve by means of conical gears 30, 31. The gears 30,31 have been positioned in such relationship that the wheels 8 of each pair of plant-pulling elements, when driven, will rotate in opposite directions.

The travelling wheels 9 are diabolo-shaped so as to be able to travel easily, during use, on ridges 32 of the ground area cultivated with potatoes.

These travelling wheels are freely revolvable on axles 33 mounted on brackets 34 and these brackets have been connected to the frame 1 by means of telescopic bars 35, 36 allowing an adjustment of height. This adjustment of height of the travelling wheels with regard to frame 1 may be performed by means of swivelling leavers 37 which engage screw spindles (not drawn). Further, a scraper 38 mounted to bracket 34 engages each travelling wheel. The distance between both travelling wheels is equal to the distance between two ridges 32 and the same applies to the plantguiding elements and plant-pulling elements.

The apparatus as described will operate as follows: Prior to utilization, the apparatus is mounted to an agricultural tractor with the aid of connecting points 2, 3, 4 and shaft 27 is coupled to the power take-off shaft 28 of that tractor. After arrival in a potato field, the height and angular position of plant-guiding elements 7, the angular position of wheel axles 1 6 and the height of travelling wheels 9 is adjusted and the apparatus is lowered to its operative position by means of leaver 6, so as to have the travelling wheels 9 resting on ridges 32 of the ground area cultivated with rows of potatoes. Next, the plant-pulling elements 8 are caused to revolve with the aid of the power takeoff shaft 28 and the apparatus is moved on the field in the direction of arrow A by means of tractor 5.If it is ensured thereby that the travelling wheels 9 will always run on the ground ridges 32, these travelling wheels will automatically provide a good adjustment of height of the plant-pulling elements 8 with regards to the ground.

During its movement in the direction of arrow A, the apparatus will successively meet many potato plants which are present on the ridges 32.

The stems and leaves 39 of these plants are engaged first from either side by the plant-guiding elements 7 and guided towards the plant-pulling wheels 8. Thereby overhanging and pendent plants may be lifted somewhat and pushed inwardly. As soon as the plants have reached the entrance of a pair of cooperating plant-pulling wheels, they are dripped by the pneumatic tyres of these revolving wheels, pulled off in substantially horizontal direction and hurled to the rear. The large surface of contact and the profile of the pneumatic tyres assist in gripping the plants and plucking if off. However, the potato tubers 40 are not engaged and will predominantly remain in their position.

The plants that have been pulled off will fall onto the ground, i.e. onto the ridge 32, behind the plant-pulling wheels and will be flattened then by the following travelling wheel 9. Further, this travelling wheel will press some soil against the tubers 40. Scraper 38 on the travelling wheel ensures that no soil with remain adhering to the travelling wheel.

As a result thereof, the connection between tubers 40 and plants 39 is definitely interrupted and germs cannot be transmitted from the stems to the tubers. These tubers 40 will remain well covered in the ground and cannot turn green, whilst the plants remain resting on top of the ridges 32 and will not be objectionable. Shortly thereafter, the tubers may be harvested in the normal way, e.g. with the aid of a harvesting machine.

It will be apparent that a good operation of the apparatus is residing mainly on the shape and position of the plant-pulling elements 8. Thanks to the use of pneumatic tyre wheels, a simple and yet efficiently operating construction is provided for. A good gripping and pulling off effect is obtained by the fact that the pneumatic tyres engage each other by a large surface of contact.

With regard to the angular position of the wheel axles 16, it has appeared that a substantially vertical position of these wheel axles, wherein the plants are pulled off in substantially horizontal direction, is advantageous. The angle of the wheel axles with the vertical need only be small and may be in general between 0 and 450, an angle of 1 50 to 300 being preferred. The most suitable angular position will depend from several factors such as soil type, potato type, weather conditions, speed of the plant-pulling wheels and the like, and may best be determined from case to case.

The operating height of the plant-pulling wheels 8 with regard to the ground is defined mainly by the travelling wheel 9 running on the ridge 32 and may easily be adjusted by turning the leaver 37, that is changing the height adjustment of the travelling wheel with regard to frame 1.

Figure 1 shows a favourable operating height wherein the plant-pulling wheels 8 will slightly engage the soil of the ridge 32, but a higher or smaller operating height may be selected according to need. This may also be determined best from case to case.

No special demands are made to the revolving speed of the plant-pulling wheels 8. Of course, the circumferential speed of these wheels should be higher than the moving speed of the apparatus in the field but an upper limit for the revolving speed can hardly be given. In most cases, a circumferential speed of 30 to 60 kiiometers per hour will be sufficient.

Several variants to the apparatus as shown are possible within the scope of the invention. Thus, the plant-guiding elements need not have the shape as shown but may have any shape that is appropriate to their purpose. Further, the adjustability of the plant-guiding elements, the plant-pulling wheels and the travelling wheels may be realized in other ways. In addition thereto the apparatus may be adapted, if desired, for treating only one row of potatoes or treating four or more rows, as stated above.

Claims (14)

1. An apparatus for pulling potato plants comprising a movable frame having at least one set of plant-guiding elements, at least one set of plant-pulling elements and at least one travelling wheel positioned in succession in the moving direction, characterized in that the set of plantpulling elements comprises a pair of cooperating pneumatic tyre wheels which are revolvable about vertical or substantially vertical wheel axles and provided with driving means for rotationally driving the wheels of each wheel pair in opposite directions.

2. The apparatus of claim 1, characterized in that the wheels of each pair of plant-pulling wheels are in close relationship so as to cause the pneumatic tyres of these wheels to engage each other and to form a large surface of contact.

3. The apparatus of claim 1 or 2, characterized in that the pneumatic tyres of the plant-pulling wheels have a profile surface.

4. The apparatus of claim 1, characterized in that the wheel axles of the plant-pulling wheels have an angle of O to 450 with regard to the vertical.

5. The apparatus of claim 4, characterized in that the wheel axles of the plant-pulling wheels have an angle of 1 5 to 300 with regard to the vertical.

6. The apparatus of claims 1-5, characterized in that the angular position of the wheel axles with regard to the vertical is adjustable.

7. The apparatus of claim 1, characterized in that the operating height of the plant-pulling wheels is defined by the position of the travelling wheel.

8. The apparatus of claim 7, characterized in that the travelling wheel is adjustable in height with regard to the frame.

9. The apparatus of claim 1, characterized in that the travelling wheel is diabolo-shaped.

10. The apparatus of claim 1, characterized in that a scraper is mounted to the travelling wheel.

11. The apparatus of claim 1, characterized in that the driving means comprise a gearbox carrying bearings for the wheel axles of a pair of plant-pulling wheels and being mounted pivotably about a horizontal shaft to the frame, said shaft extending crosswise to the moving direction of the frame and the pivoting position being fixed in an adjustable way.

12. The apparatus of claim 11, characterized in that the driving means may be coupled to the power take-off shaft of an agricultural tractor.

1 3. The apparatus of claim 1, characterized in that the plant-pulling wheels may be driven by the driving means to reach a circumferential speed of 30-60 kilometers per hour.

14. The apparatus of claims 1-1 3, characterized in that two pairs of plant-guiding elements, two pairs of plant-pulling wheels and two travelling wheels are present in the apparatus.

1 5. An apparatus for pulling potato-plants, substantially as described with regard to figures 1 and 2 of the drawings.