A new class of spreaders

It used to be that if you wanted to spread road grit over large areas in winter, you had two options: hydrauli­cally or mechan­i­cally driven spreader machines. The asso­ci­ated carrier vehi­cles with hydraulic drive or cardan shaft are often high-main­te­nance and rela­tively expen­sive – too expen­sive for many munic­i­pal­i­ties or busi­nesses. In many places this meant grit had to be spread by hand – with unsat­is­fac­tory results: more use of mate­rial, uneven distri­b­u­tion and, last but not least, high burdening of the personnel. The call for a cost-effec­tive alter­na­tive grew loud.

New niche

The “Mini­Vario” scat­ters fertil­izer or slug pellets, even on the narrow area between grapevines

LEHNER Agrar devel­oped the solu­tion. More than 10 years ago the family-owned company began by devel­oping attach­able spreader machines for nearly all types of vehi­cles, from small ATVs, to conven­tional cars, to full-fledged fire engines. But what this company on the edge of the Ostalb region in Baden-Wuert­tem­berg actu­ally specialised in was the trade of seeds, fertilisers and pesti­cides. The shift to tinkering and puzzling can be justi­fied in a typi­cally Swabian, prag­matic way: The core busi­ness of LEHNER Agrar is subject to strong seasonal fluc­tu­a­tions, which regu­larly led to a low work­load in winter. When the managing direc­tors rather acci­den­tally became aware of the poten­tial of manage­able spreader machines, they decided to engage in pioneering work in this field. Thus LEHNER Agrar solved two prob­lems at once: full-time employ­ment for the staff and the opening up of a new, lucra­tive busi­ness sector.

The tech­nical approach of LEHNER Agrar is also prag­matic. The “Polaro ” spreader machine simply uses an energy source already in the vehicle: elec­trical current. The Polaro draws its power entirely from the alter­nator via the vehicle’s voltage socket. This is how it drives an elec­tric motor which trans­fers the energy to a rotary table. Its rota­tional speed deter­mines how far the road grit flies. The user can regu­late this process contin­u­ously in order to effec­tively cover narrow walk­ways as well as large-area parking lots.

Failure rate: zero

What sounds quite simple in theory involved a few little pitfalls in the devel­op­ment. With up to 3,000 revo­lu­tions, the elec­tric motor must provide a substan­tial output, after all, but must not burden the carrier vehicle’s circuit with currents that are too high. Other­wise a 12-volt car battery would very quickly reach its limits. When it came to designing a corre­sponding motor for the spreader machine, LEHNER devel­opers received support from ebm-papst in St. Georgen. “Since the device has to run under rela­tively adverse ambient condi­tions, we decided in favour of a robust BCI motor,” explains Thomas Schrag, Branch Manager for Drive Engi­neering at ebm-papst. St. Georgen.

The “ÖlTiger” quickly reme­dies spilt oil that can remain after an acci­dent

“This brings along with it the neces­sary energy effi­ciency to keep from over­loading the circuit.” Never­the­less, the St. Georgen staff together with their part­ners at LEHNER Agrar closely exam­ined the appli­ca­tion once more to further opti­mise the effi­ciency in the rele­vant areas of perfor­mance. The BCI motor persuaded the devel­opers with its good control­la­bility and long service life with minimum main­te­nance effort. “To date we have not had a single complaint,” confirms Schrag.

With these convincing argu­ments it is only logical that the “POLARO” would turn into an absolute sales hit for LEHNER Agrar. Though only 100 units were sold in the first year, one year later it was already 1,000. They didn’t leave it at just one model for long. Addi­tional specialised spreader machines followed, such as for combating agri­cul­tural pests or for fire engines. The export of spreading tech­nology now makes up 40 percent of their busi­ness, and the trend is rising.