Snow plough blades for agricultural tractors
Usually, snowfall is abundant and sudden and requires the intervention of a specific vehicle fleet. Snow plough blades are not only an essential equipment to face the emergency but also from the technological point of view. Many Italian manufacturers have specialized in the production of these voluminous equipment, available with a wide range of models, working with advanced control systems
One of the main impact of climate change is undoubtedly a significant increasing frequency of extreme weather conditions, a phenomenon that unfortunately is now a certainty on a world scale. In countries with a temperate and cold climate, this also means intense and abundant snowfall (as in winter in the Alps) which, apart from the classic iconography of a recreational nature, entails considerable disruption to the movement of people and goods on roads, railways, and even in the airport field.
Therefore, it is essential to keep the communication routes efficient, restoring their functionality as soon as possible by clearing the snow. It is in this context that agricultural machines, and especially tractors, duly combined with snow plowing equipment (usually blade or turbine), sometimes combined with sand and salt spreaders, can do a good piece of work.
In itself, the removal of the snow blanket and the subsequent intervention to avoid the (re)form of an icy layer on the road surface seems to be a very simple operation. The reality, as it often happens, is different: in this case, we must take into account many aspects of the background, which can complicate the execution of the work. First of all, priority is to be given to the timeliness of the intervention to restore road connections as soon as possible; moreover, it is necessary to guarantee the highest cleaning efficiency, taking care not to damage the roadway itself and/or other accessory protective and signaling equipment (poles, curbs, sidewalks, panels, parapets, etc.) which are functional to traffic safety. Finally, the snow clearing is often performed while the roads are open, therefore, considering the certainly not optimal weather conditions, it is necessary to perform the operations with even greater attention and caution.
Snow plough blades
Snow cleaning can be performed with so-called snow blower turbines, which intercept the layer to be removed by a rotor usually equipped with rotary cutters, which directs the material to a lateral throwing expulsion system, or with the snow blades, moving the snowy layer on one or both sides of the roadway (or the surface that intercept in the single passage).
The coupling of snow plows is certainly not the exclusive prerogative of a single type of tractor: in fact, particularly in the road context, they can be coupled with a wide variety of vehicles, such as quads, SUVs, pick-ups, trucks, etc., even if it is undeniable that for its peculiarities the agricultural tractor can be more easily coupled, if only because of its excellent traction capacity even on off-road surfaces and/or reduced grip, the possibility of equipping (and, if necessary, operate with energy sources available on board) at the same time different instruments as well as for an optimal weight distribution, for instance together with a sand spreader or a salt spreader, which make it a stable machine also for working on very steeply inclined slopes.
Other than the many options of providing accessories and enabling special functions, the snow plough blades can be classified according the way the material is moved, ie if the snow is removed only on one side (monolithic blades, or even in several sectors movable for the modulation of the working width), or if it is moved on both sides of the carriageway (blades with plowshares).
The tractor is coupledon the front (or even rear, if the tractor is equipped with rearview system) and the coupling can be made with the lift 3-point attachment (and thus taking advantage of the possibility of moving the latter), or with dedicated plates, to be fixed in a convenient way to the front or to the carrier support, sometimes integrated with an articulated wishbone structure. In this case, the vertical movement of the blade is always provided by one or more hydraulic cylinders. The transverse movement in the horizontal plane of the blade or of its sections is similarly operated by hydraulic cylinders, to adjust the opening (or closing) angle of the blade with respect to the feed direction, which basically depends on the mass to be removed. In order to maintain high working speeds, to the benefit of the timeliness of the intervention and of higher productivity, as far as snow plough blades are concerned the blade protection (as well as the road surface) is of particular importance in the event of unforeseen obstacles. Moreover, given the peculiar characteristics of the operation, much attention has been given to the study of friction materials, ie the knife placed at the lower end of the blade, which is in contact with the ground.
Therefore, many of the functions and accessories of the snow plough blades are aimed at optimizing their performance in this sense. In detail: - overcoming the obstacles on the ground: the traditional models are based on the action of pre-stressed spiral springs (sometimes even with the possibility of adjusting the load), while the most recent evolution has replaced them with hydraulic cylinders, implemented with nitrogen shock absorbers for a quicker reactivity in the event of high-speed impact. On some models, the weight of the blade on the ground is partially unloaded on two or more sliding pads, in cast iron or some material related to that of the scraping knife - vertical inclination of the actual blade (also called “aileron”), operated mechanically or hydraulically: it is useful for the best snow removal efficiency, depending on the material adopted each time for the so-called scraping knife. In addition, the aileron can be completed with side edges made of plastic material, suitable for cleaning the snow near the “New-Jersey” type dividers, and to facilitate to move the removed material, and a rain flap (sometimes also adjustable in height) to be fitted at the top of the blade, to have a better visibility from the driver’s seat in the case of high-speed work – installation of an independent electrohydraulic control unit, for the different actuators better operating autonomy – central control device to regulate the transversal oscillation, able to compensate for the inevitable differences in load on the sides of the blade, for a more precise contact with the road surface (especially if bumpy), for the benefit of a regular consumption of the scraping blade. Besides, the system allows the blade to be locked horizontally when it is lifted during the transport, - centralized connection of all greasing points, to facilitate ordinary maintenance; - lighting of the working area, crucial under cross lighting or darkness, as well as the installation of suitable visual signaling devices, since often working on roads in operation. This is why the blades can be equipped with end-outline marker lamps, and repeater lights of the tractor, as well as additional working lights, which often make use of modern and efficient LED lighting elements.
The market
There are many domestic manufacturers (with locations mainly located in northern Italy, for understandable market issues), who ensure a wide offer of models, to meet every need, both in terms of coupling with different tonnage tractors, both in terms of completeness of functions and accessories. Without the pretension of exhausting the list, we can quote: Angeloni from Montecarotto (Ancona), Argnani e Monti from Bertinoro (Forlì), Annovi Aldo from Corlo di Formigine (Modena), Assaloni (which also has prestigious collaborations both nationally, with the Orsi Group, and internationally, with the Giletta-Bucher Municipal Winter), Autotrasporti Cavallo from Cuneo, BellonMit from Cadoneghe (Padua), Bombelli from Segrate (Milan) e Bonatti Caricatori from Pegognaga (Mantova), Daniele & Giraudo from Vottignasco (Cuneo) and Faza from Città di Castello (Perugia).
The wearing part
The snow plough blade’s scraper knife must meet two basic requirements:
1) ensure a continuous and precise contact with the road surface (for maximum snow cleaning efficiency), but at the same time do not exert excessive friction, to avoid increasing the pushing effort and, therefore, the consumption of the tractor and obviously to avoid ruining the road surface and the horizontal road markings.
2) have characteristics that do not suffer excessive wear, to prevent to be forced to frequent (and expensive) replacements. The traditional steel (almost always in the Hardox version) has long been joined by other materials. The rubber (often synthetic, based on high-density polychloroprene, the so-called Neoprene) has been the natural evolution, but more recently the research has made further progress, with the adoption of polytetrafluoroethylene (better known with the name of Teflon), or with the introduction of wear inserts in corundum, a hard and low-wear aluminum oxide, but at the same time very smooth. Alternatively, plastic materials with high elasticity and resistance are used, such as polyurethane elastomers, produced by hot molding, for thicknesses between 20 and 60 mm, which in this case show excellent resistance to dynamic stresses, low temperature dependence, excellent wear resistance, reduced permanent deformation, high impact elasticity and tear resistance.
It is easy to say “salt spreader”
The operation, in itself, is of those that are called elementary. It is enough to spread salt (or even sand) on the surface just cleared of the snow, to avoid that (re) forming of that thin, but dangerous, frozen layer of material left on the roadway. In fact, in addition to the justified need for timeliness of intervention, there are, beyond all doubts, also those of a quality of work that can need to be as high as possible. This results in the best use of salt, or spreading it where it is really needed, in the amount needed, and immediately reporting any malfunctions. The group Giletta-Bucher Municipal Winter-Assaloni from Revello (Cuneo), provides its spreader Gmeiner Tracon series with many devices, in this sense, drawing “fully” from the immense possibilities offered today by electronics and information technology.
First of all, the unfailing control unit, called Ecosat and equipped with a 7” inch display, oversees the operation of the machine, with an easy navigation based on pop-up windows. In addition to the efficiency of the machine, with the Ecosat it is possible to manage the “Route-Inform”, ie the locating function of stationary or moving vehicles and the exact parameters of spreading, as well as the “Route-Replay” system to record, store and above all reproduce the distribution routes on another occasion. The good functioning of the salt spreader is obviously controlled by various sensors: the ESK, fitted on the covering screen, signals both in an acoustic and visual way any undesired interruptions in the distribution of the material; vice versa, the ESBV uses a powerful servomotor managed by a potentiometer to define the direction of launch and the width of the distribution (in a range between 1 and 8 m) with a real-time display on the control panel.
Finally, a thermal camera installed on the machine constantly measures the temperature of the road; the obtained data are used to modulate the quantity of material to be spread through the Ecosat control unit, according to a rate previously set for the specific intervention conditions.
