US Patent 8683931 Seed metering door operation

Expensive seed wasting and crop stunting are avoided by electronically controlling solenoids to selective supply fluid pressure to double acting cylinders. Rams operate links and roller mounted seed doors. Extending or withdrawing the rams closes or opens the doors. Clips on the rams limit door openings. A microprocessor stores field dimensions and planting patterns, spacing of seed planting headers from an onboard GPS and distances of seed travel through spaced seed distribution tubes. The microprocessor electronically controls solenoids to timely shut seed doors in groups before reaching turns or unplanted headlands and to timely open groups of seed doors before reaching planting areas.