On the left front looks like a crank handle but it is in to far to be ale to make a full revolution. Looks like the max it could go is just over 1/3 revolution. Or the handle could be a way to disengage the movement once it hits a certain position. But agree that it looks like a it was designed to slit something.
Yes the handle is attached to a gear rack, but it is not one that would allow great length of movement but rather smaller amounts... I have not gotten into it too deeply yet as I have so many new toys to play with, like the 7 inch Ammco Shaper and the B.C.Ames bench top mill... Oh this winter will be a hoot