Seed metering wheel assembly

A rotatable seed metering wheel assembly comprising:

• a metering wheel having a central hub section, a circular rim outboard of said central hub section, and a series of ribs extending between said central hub section and said rib and defining through-openings, said ribs lying along respective, spaced apart, non-diameter chord lines,
• said metering wheel further including an intermediate ring between said central hub section and said rim, there being a first series of generally triangular through-openings between said central hub section and said intermediate ring, and a second series of generally quadrate through-openings between said intermediate rings and said rim;
• and
• apparatus for rotation of said metering wheel about an upright axis.

A method of metering quantities of seed in order to create a substantially constant flow of seed over a period of time, said method comprising the steps of:

• delivering by gravitation quantities of seed from a seed outlet opening to a metering station;
• and
• at said metering station, successively passing said quantities of seed through a series of seed metering openings defined by corresponding rib sections and rotating about a central, upright axis, so that the rib sections and seed metering openings present a substantially constant open area over said period of time, with at least certain portions of the seed metering opening-defining ribs extending across said seed metering openings in order to prevent wholly unobstructed flow of seeds from said outlet opening and through said seed metering openings over said period of time, and to provide a substantially constant weight and volumetric flow of seed from the seed metering wheel assembly during said period of time,
• said metering station being stationary against translation during said passage of said seed during said period of time.