This invention relates to a method of draining wetland as, for example, peatland, mosses, marshes and the like, as well as forest land and arable land, and to a device for carrying out the method.

Apart from manual ditching, lands of the aforesaid kind hereto¬ fore have been drained exclusively by means of excavating ma¬ chines of various types , by which normally only lengths of about 3 m can be ditched whereafter the machine has to be moved and re-positioned. For each such length the bucket ^" of the machine must be filled and emptied at least six times. On wetland the excavating machine must be moved and re-positioned more fre¬ quently, for preventing it from sinking down and getting stuck. It is obvious that draining with excavating machines is com¬ plicated, tedious and thereby expensive. Furthermore, at this conventional ditching method soil or peat masses are obtained which not in all cases can be placed on the ditch edges, but must be carried away. In such cases the drainage costs increase substantially.

In ditches especially in wetland the sides often collapse due to the increase in pressure caused by the masses placed on the ditch edges. The ditches thereby are filled.with mud relatively quickly and become more ^" shallow. It is not possible, either, to drain very wet land by means of excavating machine, and such ditching normally must be carried out manually.

The present invention, therefore, has the object to provide a method and a device for ditching, which do not show the afore¬ said disadvantages, but are much more rapid and rational and render it possible to ditch without producing any soil masses, which have to be stacked or transported away, and which also render it possible to ditch in such wetlands, which do not carry, for example, an excavating machine.

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This object is achieved in that the method and the device acc¬ ording to the present invention have been given the character¬ izing features defined in the attached claims.

The invention is described in greater detail in the following, with reference to the accompanying drawings, in which

Fig. 1 shows an embodiment of the invention,

Figs. 2 and 3 show the same embodiment seen from above and, respectively, from the front, Fig. •+ is a partial section of an enlarged detail of the device according to the invention, Fig. 5 shows a modified application of the invention.

The device according to the embodiment shown in Figs . 1 - 4 comprises a V-shaped frame 1 with smooth parallel sides 2 of a low-friction material, for example sheet metal. The sides 2 though shown to be parallel along their entire length may at their rear portion be formed with inclination, i.e. may be deflected inward or be given slightly convex arc-shape, in order to reduce to the greatest possible extent the counter- forces against advancing which arise especially in wet lands .

The frame 1 further is formed or provided with a plough-like forward portion 3, the forward free boundary edge 1 preferably is formed like a cutting edge, and which forwardly can be straight or undercut to arc-shape,_ as shown by dashed ^" lines 5 in Fig. 1, or be straight or overcut to arc-shape, as shown by fully drawn lines 6 in Fig. 1, or be vertical. The smooth sides 7 of the forward portion preferably consist of the same material as the frame sides 2. The V-shape of the frame can be made wider or narrower than shown in the drawings and there by be adjusted to the cross-sectional shape of the drain to be ditched. At its rear portion, the frame 1 can be formed-or pro vided with a portion similar to the forward portion 3, so that the device can be advanced in one direction or the other with¬ out having to be turned around. Along the narrow, preferably slightly rounded lower surface of the frame 1, a wear bar 8 is located which, of course, also extends over the forwarc

portuon 3 and possibly the rear portion.

At its upper part the device is provided with a horizontal plate 9, which at the embodiment shown extends over the frame in order upon demand to be able to act as a support plane for the device. The front edge portion in the advancing direction of the plate, therefore, preferably should be formed like a brim, though this is not shown in the drawings.

Said plate has the object during the ditching to show the ditch¬ ing depth of the device relative to the ground, as indicated by 10 in Figs. 1 and 3.

Within the frame 1 a vibrator means 11 is located, the stroke direction of which is indicated by the double arrow 12. The vibrator means 10 is mounted pivotally and can be set in differ- enτ angular positions relative to the g ound 10. This adjust¬ ment of the vibrator 11 is effected by a piston-cylinder means 13, which is hingedly attached between the vibrator 11 and the frame 1 by means of vibration-absorbing rubber bushings 14, and which preferably is remote controlled.

The vibrator 11 more precisely is shown pivotally attached on an axle 15, which is rigidly secured in the frame 1 and at each end is held clamped against a semi-circular surface 16 of a support boss 17 attached to the side 2. The clamping is effected by a cap 18 screwn on the support boss. On said axle a thick- walled pipe 20 is pivotally mounted by means of a number of bearings 19, which pipe is connected to the lower surface 21 of the vibrator by load-distributing flanges 22. Each of the bear¬ ings 19 comprises a slide bearing ring 23 located on the axle 15 and a slide bearing cup 24 of annular shape, which is connected to the pipe 20, and in which the slide bearing ring runs. For fixing the pipe 20 in axial direction, a distance member 26 is provided between each pipe end 25 and the adjacent support boss 17, as shown in Fig. 4.

The striking forces produced by the vibrator 11, thus, are transferred via the pipe 20, axle 15 and support bosses 17 to the frame 1. The vibrator 11 being in vertical position, the striking forces act in vertical direction and drive the V-shap frame 1 into the ground to the depth intended, which depth is indicated by the plate 9 projecting from the frame by its posi ion relative to the ground 10. The frame 1 preferably is given such height as to correspond to the ditch depth intended. In such a case, thus, the frame is to be driven down until the plate 9 substantially is on the same level as the ground, and is then caused to maintain said depth during the advancing movement of the device.

For the advancing movement any suitable vehicle, preferably caterpillar vehicle, can be used, to which the device is coupl by means of a tie rod 27 or a winch with one or more long towing wires in the case of such wet lands, which cannot even carry a caterpillar vehicle.

During the advancing of the device, the vibrator 11 acts on th frame 1 and prevents it from being lifted or pressed upward cu of the ground. The frame thus advanced in the ground, owing to its design and the downward directed striking forces produced by the vibrator, presses away the soil masses and compacts the and thereby continuously forms a ditch with a cross-septional shape corresponding substantially to that of the f ame. In certain lands, for example peatlands, a certain return expans¬ ion may occur which, however, can be compensated for by design ing the V-shape of the frame wider than the V-shape of the com pleted ditch which is conditioned by the angle of repose of th material in question.

The working depth of the device is controlled by means of the vibrator 11 and/or by changing the speed at which the device i advanced. At too great a depth of the device the speed increas

and thereby the device is pulled up, provided however that the vibrator is not changed. Such elevation ^' of the device can be effected also by pivoting the vibrator in clockwise direction from its vertical position and thereby reduce the downward directed forces of the vibrator at the same time as the forward directed forces promoting ^' the advancing movement are increased. When the device operates too high, its lowering is effected by reducing the advancing speed and/or by pivoting the vibrator counter-clockwise to its vertical position, whereby the down¬ wardly directed forces of the vibrator increase and are capable to press the frame deeper into the ground. The fluctuations in the operating depth of the device are indicated directly by the change in the position of the plate 9 relative to the ground 'level.10. In its inclined positions, the vibrator, as mentioned, also contributes to the advancing of the device. Especially in very loose lands offering low resistance to the frame being pressed down, thus, the advancement ror.oτir.g forces of the vib¬ rator are especially high.

When a vehicle equipped with hydraulics is used as traction vehicle, the vibrator should be operated hydraulically. In other cases the vibrator may be operated by an internal combust¬ ion engine or the like provided in the device.

The compacting of the soil masses effected by action of the vibrator results in stabilized side surfaces of the ditch, so that the collapse risk is reduced considerably even in wet lands. The compacting effect brought about by the device, as shown in Fig. 3 at 30, is greatest at the ground surface and decreases toward the ditch bottom. This implies the advantage that the afflux of water to the greatest part occurs in the ditch bottom where a certain hydraulic water pressure prevails, whereby the draining is accelerated. By designing the frame sides upwardly to deflect outward, as indicated by dashed lines 31 in Fig. 3, the compacting zone 30 can be increased.

"In Fig. 5 is illustrated schematically that the device accord¬ ing to the invention can be provided with attachments formed for special purposes or be used as carrying and driving unit such ^' attachments . The attachment shown in Fig. 5 is a lateral wing 32 intended for the deepening of ditches along the road, at the same time as an additional pressing of the road slope is effected by the wing. This additional pressing can be increased by arranging the vibrator 11 so as to be pivotal in the plane shown in Fig. 5, i.e. in the drawing plane, about an axle (not shown) in parallel with the direction of advance-: ent. ! 1

The present inventuon is not restricted to what is described • above and shown in the drawings , but can be changed and modifi in many different ways within the scope of the invention idea defined in the attached claims. As regards the vibrator 11, of course, its capacity with respect to aτ least the force appl per stroke and the vibration frequency or frequencies per minut must be adjusted to prevailing ground conditions and, therefore can vary within wide limits within the scope of the invention."

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