Not looking designed to crush seed.
Perhaps a seed metering device?
IF outer numbers are calibrations , a specific seed size ( by type/specie) would be likely.
It would need an inlet(gravity fed from a can on top usually , which way is up? l.o.l.) and an outlet.
Outlets could be a short pipestub a piece of hose or pipe is attached to for seed to drop through.
Other set ups exited too though.
A wild (er) guess on your piece is a chain drove the outer gear and seed fell through the slot near it.(?)