The present invention relates to a soil treating imple¬ ment, in particular for use as an after-runner in connection with harrows or corresponding devices.

It has for a long time been endeavoured to provide such an after-treating implement which, in connection with a coarse harrowing, could produce a treating result in the form of a finished seedbed, but generally these attempts have not been successful. Mostly, the proposals have dealt with drum implements, which may well break and smoothen earth lumps, but this is not a satisfactory aftertreatment, because after a coarse treatment there will still be coherent plant root formations and lump formations down in the soil, such that a smoothened surface alone will not condition the preparation of a good seedbed.

It has been endeavoured to break these solid formations by the use of different forms of working teeth or threads or even by powered cultivator drums, but the results have been either bad or unacceptably expensive.

With the present invention it has been found that it is in fact possible to solve the problem in an economical and efficient manner, viz. in using as aftertreating tools a row of rotary cutter discs driven by the earth friction and made with coarse indentations so as to exhibit wingshares having a sharpened front edge and a laterally bent-out rear wing blade portion. With the cutter wings projecting down in the soil, these cutter discs will be forced to rotate during the pro¬ pulsion such that the wingshares are successively turned downwardly so as to cut through roots and lumps, whereafter the laterally bent out rear wing blade portions, by the fol¬ lowing turning up from the soil, will operate to broad-spread the cut material for obtaining both a mechanically well pre¬ pared seedbed and a good admixture of the plant rests in the upper soil layer.

Ultimatively, the invention aims at a soil treatment of grass and stule fields, whereby it is possible to completely renounce the traditional ploughing and only make use of a

single or a few treatments with cultivator or harrow imple¬ ments with an afterrunner according to the present invention.

In the following the invention is described in more de¬ tail with reference to the drawing, in which: Fig. 1 is a schematic perspective view of an arrangement according to the invention;

Fig. 2 is a plan view of one of the coarsely indented cutter discs used therein;

Fig. 3 is a sectional view thereof; and Fig. 4 is a perspective view thereof.

In the system according to Fig.l, a first soil treating device A is indicated, e.g. in the form of a stule harrow or a combination of two different devices propelled by a tractor in direction of the arrow shown towards the right. As an ad- ditional, afterrunning implement there is arranged a unit B according to the invention, comprising a row of passively ro¬ tary cutter discs 2 provided with marked, triangular inci¬ sions 4 in their periphery, between which there are left pro¬ jecting wing blade portions 6. As shown in more detail in Fig. 2-4, a portion of each of these wings is bent out to one side along a bending line "a", which extends obliquely to the effect that a wing blade front edge 8, which is leading in the direction of rotation, is bent out only at a short outer end area 10, while the rear edge area 12 is bent out along the entire or almost the en¬ tire length thereof. The degree of bending may be more or less, but for achieving a noticeable effect the bending angle should not be below some 10° and not above some 60°. A pre¬ ferred interval is 20-50°. The depth of the V-shaped incisions between the cutter wings should be some 25-75% of the wing radius, preferably some 50% as shown in Fig. 2. The number of cutter wings may be up to 10-12, but preferably lower, viz. 5-8 or 6 as shown in Fig. 2. In Fig. 1 it is indicated that the cutter discs 2 may be arranged in groups, each e.g. with four discs mounted on a common shaft in such a manner that the wingshares 6 in the respective groups are phase displaced from each other, for

formation of a treating unit which, despite the coarse inden¬ tation of the cutter discs, yet forms a collected, contiually operating rotation unit which, in projecting into the soil e.g. to a depth indicated by the dotted line shown in Fig. l, will be influenced to rotate constantly during the propelling of the implement.

When the implement is driven forwardly with a conventio¬ nal working speed, the cutter discs will rotate vividly, whereby the cutting front edges 8 of the wing blades, during their downstroke in the ground and by their swinging up therefrom, will excert a cutting and separating effect, while by their upstroke the bent out wing portions 6 will cause an up- and ourthrowing of earth and plant portions. When this occurs at each wing blade passage the result will be a heavy turbulence, by which it is achieved that the plant portions are effectively admixed into the earth in conjunction with the soil surface being effectively loosened. This implies a good moulding down of straw and plant portions and an effi¬ cient preparation of the seedbed. Preferably, the cutter discs are arranged such that they throw out the earth to both sides of the middle of the imple¬ ment.

The bending lines "a" may be located otherwise, and the bendings should not necessarily occur along a single bending line. Thus, there may well be a curved transition between the disc body and the wing blades 6. Such a transition is indi¬ cated on the lower wing to the right in Fig. 2, where a fan of bending lines a' is shown; by this fan formation the wing tip will not only be bent out, but also twisted somewhat, which has been found particularly advantageous. Optionally, the wing tip may be prolonged as indicated in dotted lines. The number and the width of the wings may be varied as de¬ sired, and the wing periphery may be sharpened.