Some light hints that may point you in the right direction:
Hint 1
The assembly is a part of a larger machine.
Hint 2
Several assemblies are meant to move side by side in unison.
Hint 3
The square-ish shaped piece is plastic that will wear down and be replaced.
Does this push paper along a track or converor by its edge? For like a newspaper or something?
Spot on.
Answer
It’s for pushing mail into an envelope. Three or four of them work in unison to push a stack of papers/inserts into an envelope.
God damn. That’s the hardest one I’ve seen in a long time. Very nice.