Broadcast spreader
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A broadcast seeder, alternately called a broadcast spreader, is a tractor implement commonly used for spreading seed, lime, fertilizer.
Broadcast seeders/spreaders can be roughly divided into three groups. The smallest of the broadcast seeders/spreaders can be carried or pushed while spreading seed or fertilizer. The next size up is designed to be towed behind a garden tractor or ATV. Very similar in size to the tow behind units are broadcast seeders that mount to the 3pt hitch of a compact utility tractor, these are ideal for landscape and small property maintenance. The largest size units are commercial broadcast seeders/spreaders designed and sized appropriately for agricultural tractors and mount to the tractor's 3pt hitch. The broadcast seeders that are mounted to a 3pt hitch are powered by a power take off (P.T.O.) shaft from the tractor.
The basic operating concept of broadcast spreads is simple. A large material hopper is positioned over a horizontal spinning disk, the disk has a series of 3 or 4 fins attached to it which throw the dropped materials from the hopper out and away from the seeder/spreader. Alternately a pendulum spreading mechanism may be employed, this method is more common in large commercial spreaders. The photos clearly show the material hopper, these hoppers are commonly made of plastic, painted steel or galvanized steel.
Some seeders/spreaders have directional fins to control the direction of the material that is thrown from the spreader. All broadcast spreaders require some form of power to spin the disk. On hand carried units, a hand crank spins gears to turn the disk. On tow behind units, the wheels spin a shaft that turns gears which, in turn, spin the disk. As is partially visible in one of the photos, with tractor mounted units, a mechanical P.T.O. shaft connected to the tractor and controlled by the tractor operator, spins the disk. There are some seeder/spreaders made for garden size tractors that use a 12 volt motor to spin the dispersing disk.