Mechanized grape harvesting

Grape harvesting in Brazil is still done manually in most vineyards. But in this scenario, it is already possible to see machines carrying out the task previously done by the hands of workers, an operation that in other countries already has a higher rate of mechanization. 

The new technologies embarked on projects aimed at agricultural mechanization allow, although recently and practically non-existent in Brazil, the mechanical harvesting of grapes. This reality has been widely disseminated and adopted in countries in Europe, Asia, Oceania and North America for more than 30 years. In South America, Chile and Argentina were the pioneers in introducing these machines to replace or complement traditional manual harvesting in the mid-1990s.

The lack of labor and the attempt to reduce production costs mean that Brazilian winegrowers are starting to invest in mechanized harvesting, even if in an incipient manner, after all, the first machine acquired for Brazilian territory was five years ago in region of the Campaign of Rio Grande do Sul, in the municipality of Santana do Livramento.

The concern of the viticulture sector in developing machines to replace manual harvesting is not new. In 1953, the University of California, United States, presented the first concept of a machine designed to harvest grapes. It was a mechanism attached to the agricultural tractor, with the active organ being a cutting bar responsible for extracting the grape bunches from the plant. In this race for development, Cornell University (USA), in 1957, proposed a harvesting system using low-amplitude, high-frequency vertical vibration to collect grapes grown in an espalier system, a necessary requirement for mechanized harvesting.

During this process of evolution, with the objective of developing a satisfactory technology for harvesting grapes, previously, these inventions had been registered, patents, thus, machines were designed with different principles for harvesting grapes that did not have great acceptance by the market. , such as machines with a suction or air blowing system, which could be used in any driving system, as well as other ideas for harvesting mechanisms. However, the system that prevailed was using shaking rods, which probably began in 1969. Created by Joseph R. Ortin, from the Chisholm Ryder Company, called the Grape Harvest Machine (Grape Harvestin Machine) it was the registration of a trailed type grape harvester, coupled to the agricultural tractor with PTO drive, with a collection system that gave rise to the shaking rods that are still found today. From this event onwards, several machines were launched with the same principle.

Among the various existing patents, it is worth highlighting that of Andre Fontan, from 1981, as it was a proposal for a lower cost machine in relation to those offered on the market until then, with simple suggestions, such as the slope for only one side in the grape sealing and transport system. At the time, shaker rods had free ends, a trend that was innovated in 1987, when the rods began to have their ends fixed to alternative rotating axles. Thus, their arches were responsible for the grapes falling off. In particular, this small innovation actually allows the stems to be introduced deeper into the vegetation, improving the efficiency in collecting the grapes, in addition to reducing the detachment of leaves and other branches and, in addition, they can work at higher frequencies and with smaller range of motion. The rod system with fixed ends is a general trend among manufacturers.

AT THE MOMENT

Probably one of the biggest concerns in the wine sector is the possibility of selectively harvesting grapes, since harvesters collect grapes equally along the lines, without any distinction between the harvested product.

Thus, patent No. US20120192539 A1, dated August 2012, proposes a grape selection mechanism to be equipped in self-propelled harvesters with greater capacities, where its employability would be in plots that present some variability and quality in the parameters, such as example, maturation, pH, sugar concentration. One or more parameters can be chosen for the selection of fruits and, thus, they would be destined for one of the machine's reservoirs, generally consisting of two. This system is made up of two small mats, one for each reservoir and a larger mat with two directions of displacement located below this set of mats, with the purpose of sealing and assisting in the destination of the grapes to the intended reservoir according to the harvest parameters previously entered into the yield monitor.

This system can be applied to other fruit harvesting machines driven on trees or bushes, such as grapes, fruits or olives. One of the justifications for this invention lies in the fact that advances in grape harvesters did not meet the selectivity criteria of the harvested fruits, an operation that can be adopted in manual harvesting, depending on quality and yield, with the purpose of optimizing the process. of winemaking.

Obviously, for this system to operate satisfactorily, the harvester must be equipped with a computerized system, commonly used in precision agriculture, so that the different maps of the plot can be read, as well as generating data related to the harvest.

As already mentioned, vineyards where mechanical harvesting is used need to be carried out using the espalier system, however, for their structure, among other materials, poles are used to form the lines, spaced every five, eight or ten meters. These elements end up becoming obstacles for the harvester, interfering with harvest efficiency or even resulting in mechanical damage. Thus, in 2013, Roger Pellenc and Jean-Marc Gialis patented a mechatronic system for controlling the shaker rods that feature the mechatronic movement control mechanism in the upper part of the collection tunnel.

Basically, in the conventional system, three adjustments are possible: agitation frequency; amplitude of the arc movement, through variation in the positioning of the ends of the rods, and change in the radius of the stirrer mechanism crank. Therefore, once adjusted, it is not possible to vary the tensions generated in the rods. This way, when the machine passes over a post, the rods employ the same movement applied to the vine, which leads to unnecessary wear on this element or the occurrence of damage.

This invention is made up of hydraulic systems, sensors and electronic controllers, so it is possible to vary the flexibility of the rods or even momentarily stop these mechanisms when faced with a considerable obstacle.

However, this proposal has the disadvantage of greater energy consumption, around 40% to 50% compared to the conventional system, in addition to requiring elements to cool the hydraulic system.

Published in April 2014, the patent authored by Frenchmen Jean-Paul Berthet and Bruno Montalgu, entitled (Fruit Harvesting Unit and Harvesting Machine Comprising such unit), is a set of additional shaking rods attached to the upper front and/or rear part of the platform (or tunnel) for collecting fruit from the harvesters. In particular, this invention is justified when the intention is to harvest fruits from bushes in rows such as olives (ultra-intensive system) where, to carry out the harvest, it is necessary for the entire height of the tunnel to have shaking rods, since the fruits are also arranged in the aerial part of the plant, unlike what happens with grapes, where the fruits are basically found in a certain height range. In this way, it would justify the application of this device, as it would eliminate the need to increase the height of the machine from the ground, reducing the center of gravity, therefore, improving its stability and, thus, it could be used on steeper terrains, compared to when not equipped with with this mechanism.

The crop, when entering the tunnel, has its aerial part curved, and in order for the fruits to be collected inside the canopy, it is necessary to use two shaking mechanisms.

FINAL CONSIDERATIONS

No different from other industrial sectors linked to agriculture, the industry focused on viticulture technologies is equally competitive and dynamic. Every year, improvements and innovations associated with this sector are proposed. Brazil, even though vineyard management and harvesting are still conventional, has already begun the mechanization process. In other countries, full mechanization on some properties should soon be achieved.

After all, viticulture also seeks to reduce costs and increase efficiency in its processes and stages, as this is one of the paths to sustainability and permanence for the winegrower.

Mechanisms of a grape harvester

For a better understanding of the operation of a grape harvester generally sold, we will cover in general terms the mechanisms existing in these machines. Item (1) identifies the shaker rods, responsible for detaching the berries from the bunches, which fall onto the sealing system (2) next to the vine trunks, in order to prevent them from falling to the ground and then the grapes roll into the system transport (3) to the grape reservoirs (4). During this process, the harvester has vacuum cleaners and crushers (5) to remove material lighter than grapes.

Wilson Valente da Costa Neto, Unipampa//UPM-ES; Pilar Barreiro Elorza, UPM-ES/ETSIA/LPF_Tagralia

Article published in issue 153 of Cultivar Máquinas.