The subject of the invention is a thinner for row crops, which consists of a connection mounted on a tractor, measuring the thickness of the crop stalks and supplying data to a computer, and the computer output hoeing_tool control mechanisms. At the present" level of technology crop production, the crop cultures, due to mechanization, cover sowing in rows, planting in rows, bedding seedlings in rows, and planting with culture medium cubes placed in rows.

In this specification the crop placed in rows are called row crop.

Earlier the so called single-seed sowing, or planting was intro¬ duced in the crop cultures, in the case of which the thinning operation was no longer required. Besides the advantages, however it could happen that the only seed, or seedling was weak, un¬ certain in productivity, or it did not even spring up. Thus the thinning operation was resumed, and new and even newer methods have been developed for performing it mechanically, thoug as it can be read in the literature, "Me όgazdasagi Kislexikon" /Agricultural Pocket Encyclopedia/, Mezόgazdasagi Kiadό, Budapest 1989 _» p.473; row cultivation: breaking up the soil, destroying the weeds around the crop growing in rows and on the strips of land directly beside them, and the setting of the favourable num-

ber of plants at the same time. This operation is difficult to mechanize, thus it is usually limited to chemical treatment, and the number of plants is sβ ^~ already at the time of sowing. Thus the thinning operation of mechanized crop production in row cultivation leaves much to be desired, namely the manual operations.

We have also studied this question in journals, where we could not find any- acceptable, or mechanically feasible solutions for thinning•

In the course of studying the patent specifications, we found that the solution of specification registration No. HU 133 630 i "A. hoe mechanism"., which is arranged on a vehicle and can swing transversely to the direction of advance, with hoeing tools, the swing of which is controlled by the feeler or tentacle-like ex¬ tensions bumping against the crop stalk or other obstacles. The solution is suitable for hoeing between the rows and in the rows, unfortunately, however, the thinning operation was not even aimed at.

The essence of the solution of specification registration No. HU 149 453 under the title "Automatic swinging hoe row and be- tween-rows cultivator" is that it has a feeler rod on a height adjusting axis on the ^" tractor, and a lever turning around a pin supplied with current by an electric control mechanism upon the turning of the feeler rod, electromagnets reaching between them and tracting them to themselves, a valve mechanism operated by the free forked end of the double-arm lever, releasing high- pressure air from an air tank into the space of an air cylinder, from the air cylinder to open air, single-arm levers hinged on the air cylinder piston rod lifting system, and swinging tools, or swinging hoes, turned between the crop rows by means of rods against tension springs. With this solution it is also possible to hoe the strips of land between the crop rows, unfortunately, however, it cannot perform thinning either.

Specification registration No. HU 170 662 is "Equipment for thin ning agricultural row cultures, especially for sugar-beet". This solves the thinning of sugar-beet in such a way, that the driving shaft is connected to a feeder equipped with claws, in spring supported swinging handle connection with the driven shaft, which is formed to establish connection with the claws of the feeder and is equipped_with bumpers, whϊchTare placed periodically on the operating lever in contact with the releasable core of the electromagnet.

This solution is suitable for the thinning operation, unfortu¬ nately, however, it cannot be used for selecting plants, for choosing the developed sugar-beet seedlings, as it leaves one εigar-bββt seedling for the given distance, which can be less suitable for production than the more developed seedling beside it.

On summarizing the present level of technology we found that the solution of the thinning operation of field crops, maize, beet, etc., a task difficult to mechanize, is the task of the future, as the methods, equipment developed so far, do not make it poss¬ ible.

Our aim with the invention is to avoid the disadvantages describe above at the present level of technology, to eliminate this very hard manual work, manual thinning, to develop thinning equipment suitable for a new. method.

Thus the solution in accordance with the invention is a thinner for row crops, which consists of a connection mounted on a tracto measuring the thickness of the crop stalks and supplying data to a computer, and the computer output hoeing tool control mechanism in such a way, that the ultrasonic, or infrared, or radar, or light operated sensor head of the trailing thinner, for the crop stalks in at least one row of the crop, is connected to the input of a computer, and the -output of the computer is connected to a tool controller with a hoeing tool sinking into the soil, inter-

vening hydraulically, or pneumatically, or electromagnetically, for a given distance of the row crop.

The solution in accordance with the invention is presented in more detail in a construction example on the basis of a drawing, where

Figure 1 is the top view of the thinning equipment, Figure 2 is one of the side views of the hoeing tool and its mechanisms.

As the equipment is seen in Figure 1, a /2/ power machine or a tractor is shown on the /l/ soil between /3/ crop rows. The /2/ power machine is connected to a /•%/ computer by /5/ machine sus¬ pension mechanisms, where the /9/ betwβen-rows cultivator mechan ism connected before the /4/ computer is known in itself, as there is a wide choice of such solutions both in practice and in the literature. The /10/ sensor head is on the /2/ power ma¬ chine side of the /4/ computer, constructed with one from among the ultrasonic, or infrared, or radar, or light operated mechan¬ isms. The /ll/ tracing wheel for the soil is indicated behind the /10/ sensor head. Beside the /4/ computer the /6/ tool shank is fixed in the /12/ tool shank frame, inside it is the /8/ tool controller, which intervenes hydraulically, or pneumatically, or electromagnetically, naturally in only one of these ways, with the /!/ hoeing tool sinking into the soil to a depth of 1-2 cm, depending naturally on the type: of the crop.

The operation of the equipment in accordance with the invention is surprisingly simple, as the /2/ power machine is usually a tractor or similar with /5/ machine suspension mechanism, and naturally in case of multi-row cultivation any number of /4/ computer mechanisms can be connected by means of a cross arm not indicated, with such a width that can be carried by the /2/ power machine. In the followings only the case of one /3/ crop row will be described, where the /10/ sensor head is 0.5-1.0 m ahead of the /7/ hoeing tool in the /3/ crop row, thus the /4/

computers have the choice of that distance to give a signal, upon the signalling from the /10/ sensor head, to the /8/ tool control¬ ler of the /7/ hoeing tool, to leave the most developed plant for the distance practicable in row cultivation, specified for the type of the crop, and to cut out all the other plants from the row, including, naturally, the weeds as well, and such a cultivation achieves perfect thinning in accordance with the gears of t. /2/ power machine.

The main advantage, of the solution in accordance with the inven¬ tion is the mechanical solution for the thinning operation, through which this hard manual operation of the crop cultures can be performed by one tractor driver in any number of rows simply and in one pass.

The disadvantage, of the solution in accordance wit., the invention is that the equipment has to be. constructed, or purchased from the manufacturer.