To drain, but also to irrigate, the gripper-ditchers
Ditch excavation machinery is normally used to improve drainage in soils subjected to water stagnation, but it is also useful for digging furrows to lay pipes for underground irrigation. The manufacturers have developed models and accessories able to satisfy all the needs
Climate change now it is a reality, which in our areas involves a radicalization of meteorological phenomena, with prolonged drought periods followed by intense rains. Obviously, these events hamper an optimal agricultural management, so we must work to limit their negative effects. Especially if the soils are particularly sensitive to water stagnation, the solution always applied is drainage, which can be underground, or more often superficial. In the latter case, in addition to a network of channels for the conveyance of excess water, ditches of different shapes and sizes, more or less temporary, are created locally. The machines used for this purpose are, in fact, the ditchers. This equipment is carried by the tractor, on which one or more strong rotors (often of considerable diameter) work, equipped on the outer circumference with a series of tools of various shapes able to turn over the ground. The rotor is rotated at high speed, in order to optimize the impact of the tools (sometimes also consisting of curved hoes) through a mechanical transmission of shafts and gears, which takes the motion from the tractor standardized power take-off at 540 or 1000 rpm/min. The ditcher progressively sinks into the ground because of its own weight, and the working depth is defined by the position that the equipment takes to be operating through the appropriate adjustment of the lifter, which in this case works in a controlled position. The removed earth can be spread on one or both sides of the excavation or intercepted and deposited on the edges of the ditch by through adjustable bulkheads, to create additional embankments. The creation of the ditch can be extremely difficult if there is a lot of skeletal soil or even rocks or stones of a considerable size, therefore, in these cases, it is advisable to equip the excavation wheel with wear-resistant tools or, in the most extreme cases, with tungsten carbide. Furthermore, in order to preserve the entire kinematic chain of motion from possible damaging overloads or even breakages, it is necessary to equip the drive shaft with a protection device. The most frequently adopted ones are the shearing bolt (economic, but boring to be maintained, because each break must be replaced, of course with an identical sample) or the multi-plate dry clutch, rather expensive but excellent because it is possible to adjust the intervention threshold. Types and fittings Depending on the operational needs the ditchers can take different working positions compared to the tractors to which they are coupled with. Given that this is a carried equipment, that is to say, fixed to the three-point hitch coupling and managed in the field by the lift (sometimes with the help of a small support wheel, but only for transportation), the ditchers can work centrally, that is to say in line with the tractor, or move sideways (mechanically with a head screw, or even hydraulically), sometimes only on one side, sometimes on both sides, thus making the ditch in an offset way, several tens of centimeters from the forward direction. A third option is also offered on the market, for which this equipment is mounted on a lateral articulated arm operated hydraulically which can move the rotating head at a considerable distance from the tractor. This is a particularly useful option when, due to operational needs, the tractor cannot transit where the ditch will be created, and also for the maintenance/creation of road docks. If the lateral translation is relatively limited, the transmission of the motion to the excavation wheel is mechanical and carried out through the cardan shafts, while if the working part is mounted on a hydraulic arm, the rotor is inevitably moved by a large hydraulic engine, which, therefore, requires a considerable flow of oil under pressure from the hydraulic circuit of the tractor. Moreover, according to the different ways in which the working organ is positioned, the models differ for the number of installed rotors. The simpler ones, called “single-wheel”, work with a single excavation wheel, with a strong rear frame which has the task of conforming the section of the ditch; the next step is the “singlebiwheel”, i.e. machines that, in addition to the rotor, which operates on one side, are equipped with a cutting and cleaning disk on the opposite side, to better sculpt the edges of the ditch. With the single-wheeled and singlebiwheeled, logically, the dirt is thrown (or deposited) only on one of the sides of the ditch. The most complete models are the “biwheeled” which, as the term suggests, are equipped with two rotors, which unload the soil on both sides and which better profile the walls of the ditch. To meet some specific needs, some manufacturers also offer the excavation wheel with particular shapes, with increased widths and cutting tools of various shapes. The most common ditchers make a typically trapezoidal section excavation, which can have a different angle of inclination of the walls (between about 20° and 45°), and obviously, a different depth compared to the ground level, and finally the possibility of having an “expanded” bottom. Furthermore, additional embankments can be made, channeling the dirt on the edges of the excavation, through strong, properly regulated bulkheads. Since it is a heavy work for the tractor, with the engine almost exclusively engaged by the power take-off, the typical feed rates are very low, from less than 1 and up to 1, 5 km/h, depending on the weaving, the presence of the skeletal soil and the degree of soil compaction. It is therefore advisable to use tractors equipped with gearboxes with a super reducer. In order to facilitate the action of the digging gear wheel, it is sometimes mounted in front of and in line with it a subsoiler anchor, which previously moves the soil, facilitating its removal. The accessories Some accessories enrich the equipment of the ditchers: apart from the transport wheel and the devices against overloads that accompany the cardan shafts supplied, there are also the hydraulic management of the three-point hitch, the hydraulic adjustment of the side bulkheads and above all the interesting option of the laser slope control, very useful for creating precision hydraulic works, which require a defined direction of drainage of the waters.
Safety
By their nature, the gripper-ditchers undermine a considerable amount of soil, strongly throwing it outwards. However, there is the possibility of intercepting and blocking the flow of material near the ditch formation area through some bulkheads installed for this purpose. The position (that is to say the inclination) of these bulkheads is adjustable (sometimes even hydraulically) to allow a specific direction of the excavation product.
Therefore, in view of the danger, which cannot be eliminated, of throwing not only dirt but also stones and rocks, the ditchers must be equipped with a specific danger signal, visible from a considerable distance, that warns any third person to stay away from the machinery.
A further important safety aspect, in this case, connected to the mechanically actuated models of the rotor or the rotors, is the adoption of a cardan shaft equipped with an overload protection device. The simpler ditchers mount the bolt security safe system, while the more advanced and performing ones adopt a multi-disc dry clutch.
It is never useless to remember, in this regard, that the protection of the cardan shaft (and more generally of the entire motion kinematic chain) must be intact and correctly installed, and properly completed at its ends by counter-cones or screens, mounted around the engine jacks on the tractor and the implement sides.
Also for the installation of underground irrigation pipes
In a slightly different version, the so-called “gripper ditchers” can also be used for laying drains or underground irrigation pipes but also, outside the agricultural area, of various kinds of pipes, always on an earthy ground.
In this case, the machinery has the rotor working vertically, and opens a very narrow furrow, from less than 10 to about 20 cm, but particularly deep, up to over 1 meter. The working tools are curved hoes, which are able to effectively remove the soil, creating an excavation with compact and homogeneous walls. Similar to traditional models, the soil can be dispersed sideways compared to the forward direction or retained on one of the excavation edges for any subsequent backfilling, especially necessary when laying underground irrigation pipes.
Many manufacturers provide on demand a pipe layer kit, in order to perform the entire working routine in a single pass. In view of the considerable depth normally obtained in the excavation, under these conditions, it is highly advisable to adopt the tungsten carbide bearing rotor, to work effectively even in tough soils, but above all to increase the resistance of the working organ in case of impact with stones and rocks.
For specialized cultivations
A careful water regulation of the vineyard and of the orchard is essential to avoid damaging surface and underground water stagnations, with consequent states of crop suffering, sometimes even for a long time, potentially capable of compromising more crops.
In such cases, it may be useful to create small ditches, also called drains, which collect and convey excessive rainwater, so as to preserve an acceptable aeration of the soil (very often very compacted by the repeated passages of the agricultural machinery in the inter-rows), to the advantage of a good state of health of microflora and microfauna.
In order to realize the ditches, small ditchers are usually used, which can work at a limited depth, generally no more than 30-35 cm, to avoid disturbing the most superficial roots of the crop.
Unlike the traditional ditchers, the excavation wheels used for this application work with the axis of rotation transverse to the tractor forward direction, thus creating a small ditch that has no trapezoidal cross-section, but basically semispherical.
Usually, for limited depth and excavation sections, the operations do not require high powers, so this machinery can be advantageously coupled to small tractors for vineyards and orchards without any particular operational problems.
