Case story

Ropa potato harvester: Accurate positioning with electric actuators

In 1972, Hermann Painter surprised, thrilled and amazed the professional world, with his first self-propelled sugar beet harvester. From his idea, his inventiveness and his courage, he went new ways and started the company ROPA.

Today, the company, located in Lower Bavaria, not only sells harvesters and cleaning loaders for sugar beets. For several years, ROPA has turned its attention to the potato market.
In developing the two-row trailed potato harvester Keiler (wild boar) II, ROPA has remained true to its corporate philosophy and has broken new ground.

The degree of automation in this machine is, in comparison to other machines, extremely high. Besides numerous hydraulic options, like the automatic axle displacement or the automatic ridge pressure regulation, electric linear actuators take over tasks such as adjusting deflection rollers, finger combs and pintle belts. Seven LINAK electric linear actuators ensure precise movement for the harvester.

The engineers from ROPA designed the machine from scratch. It is probably unique in having this number of adjustment possibilities in order to optimize the harvesting process. Regardless of the power take-off rotation speed, many elements can be adjusted hydraulically. In applications, in which high positioning accuracy is a must, electric actuators are used, and not hydraulic cylinders.

“Especially adjustments where you have to set a very fine dosage, for example, adjusting deflection rolls or in transition areas of cleaning elements, we chose electric actuators,” explains Dr. Rupert Geischeder, an experienced division manager, responsible for the entire potato harvester product range.

ROPA potato harvester with LINAK actuatorsLINAK electric actuators are used for the positioning of numerous cleaning elements and deflection rolls.
 

For this application area, ROPA exclusively uses the LINAK LA36 actuator. They are characterized by their strength, their robustness, and their various control options. One of these precise positioning adjustments occurs with the pintle belts. The pintle belts remove the soil from the harvested potatoes. The accurate electrical positioning of the pintle belts allows for a comfortable harvesting process via touch panel.

The staff working on the potato harvester is not only able to adjust the pintle belts electronically, but also other cleaning elements. Thanks to the infinite stepless positioning possibilities, the resistance paddles, necessary for removing the greens, can be adjusted so that even when the potato greens are lush, the crop loss is kept to a minimum.

Dirt, dust, water and varying temperatures - the electric actuator must function properly despite these harsh environments. Downtime during the harvest season would have great financial consequences for the farmer.

 “LINAK sets the benchmark in terms of robustness of electric variable actuators”, explains Dr. Rupert Geischeder.

In fact, the Danish manufacturer has placed a special emphasis during the development of the linear actuator LA36 on use in hostile environments. The LA36 fulfils protection class IP66 in a dynamic state and IP69K in a static state.

“In many applications in the agricultural market, the actuator is already in use and has proven itself”, illustrates Günther Rappl, LINAK sales manager for Bavaria.

ROPA potato harvester with LINAK actuatorsThe linear actuator LA36
 

In addition to the linear actuator LA36, numerous other LINAK actuators meet these high protection classes. A further special feature of the ROPA potato harvester is the control of the actuator. The replacement of a hydraulic cylinder with an electric actuator should be as simple as possible. This also applies to the computer output capacity.

“We had to meet certain requirements for this application, and we have done this, together with LINAK”, says Dr. Rupert Geischeder.

The keyword is pin control. Because of the complexity of the machine, the outputs of the control boxes were for the most part occupied. Therefore, it had to be possible to control the actuator, meaning run out / run in, with a single wire control.

“We have developed a custom software that makes the single wire control possible,” explains Günther Rappl. ”This makes it possible to control the electric actuator like a hydraulic cylinder.”

 

Electricity replaces hydraulics

Besides robustness and customized control, electric actuators offer additional advantages. For example, the weight plays an increasingly important role. When implementing a movement system in such a large machine, the electric solution saves valuable weight compared to a hydraulic system. Electric actuators also receive a high score in the area of maintenance-free systems. Not only the positive attributes of an electric actuator convinced ROPA, but also the close cooperation with the product developers at LINAK. 

“We decided to use LINAK actuators, because we have a high degree of trust in the robustness of the product and also in LINAK‘s experience with agricultural machinery movement“, he concludes.

ROPA potato harvester with LINAK actuatorsDr. Rupert Geischeder is responsible for the entire potato harvester product range
 
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Electric linear actuator solutions for agricultural machinery from the LINAK TECHLINE segment

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