ROW BY ROW / March 2019
A component-by-component look at what makes Drago the most advanced corn head in the industry.
Editor’s Note: From the low profile of its row units to the fin design of its auger, every component of the Drago corn head is engineered for added yield and durability. This is the second in a series of Row by Row articles detailing how Drago’s “yield-first philosophy” influences the design of its components.
Part 2: Knife rollers
Regardless of brand, knife rollers perform essentially the same job, and that is to pull down stalks and separate the ear from its stalk. How well each brand accomplishes that job is what separates Drago’s knife rollers from its competition.
Building a better knife roller
“There isn’t any one thing that makes Drago knife rollers superior to other brands,” begins Dustin Bollig, Marketing Director for Drago Corn Heads. “It’s a combination of features including roller length, width and knife design, and how they work together, that makes them unique.”
At 22.5 inches, Drago knife rollers are the longest in the industry. “The extra length delivers added time to process the stalks,” Bollig says. “But simply having longer knife rollers is no value if stalks are unable to travel the entire length of the knife roller, and that’s where our knife-to-knife configuration plays a significant role.”
He explains that the knife rollers of some other brands never let go of the stalk once contact is made – their blades alternate or intermesh with each other in a crimping fashion, this creates a restriction and prevents stalks from moving up along the roller.
“That nearly all of the plant processing takes place within the first two or three inches of the knife roller, regardless of its total length,” Bollig says. “We know that because eventually, that’s where you see most of the wear taking place, too.”
Bollig adds that one of the consequences of a limited processing window is that the knife rollers must run faster, resulting in more ear bounce.
In contrast, each Drago knife roller features four blades that meet, pinch and let go with every rotation, allowing stalks to move back into the row unit before the ear is separated from the stalk, Bollig explains. “Getting that separation further back into the row unit – as much as three-quarters of the way back – provides added assurance that ears will be captured.”
“One other significant feature with our knife rollers is their small diameter,” he adds. “A smaller diameter means they don’t pull stalks down as fast as brands with larger knife rollers.”
“The slower tip speed means we get less bounce, less shelling and more ears into the machine.”
“Again, every feature of our knife rollers is important,” Bollig says. “Their smaller diameter reduces the speed that stalks are pulled down, we can run at a reduced speed because our knife rollers are longer, and stalks are processed the entire length of the rollers because of the configuration of their knives – all of this happens while getting extended, more gradual wear.”
And while Drago knife rollers work to deliver more corn, they are also engineered to work longer. Unlike other major brands, Drago supports the front of its knife rollers with brackets to keep them from spreading and breaking.
“That’s important considering today’s high plant populations and robust stalks that can apply side-load pressure on unsupported knife rollers,” Bollig says. “Over time, that side-load pressure can eventually result in shaft breakage or gearbox failure.”
Bollig notes that even with bracket supports, the potential for foreign objects entering row units and causing damage remains. “Should that occur, Drago gearboxes feature orbital bearings designed to allow rolls to spread and prevent such damage,” he says. “The operator can simply reset the rollers and continue harvest.
Finally, along with the knife roller bracket, Drago features two bearings and a grease bank built into the nose cone itself. A dirt barrier is milled into protect seals and bearings when tops are closer to the soil, as in down-corn situations.
He adds that whether a component is designed to capture more corn or to add strength and durability, Drago design and engineering demonstrate the level of detail and harvest intelligence that is unmatched in the corn head industry.
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