[GreenKeys] model 28 paper winder...another question

[Steve]

Over the weekend I picked up a paper winder (model 1A45, code LPW300GA)
from the guy I got my model 28 from a while back. He was not sure if it was
originall attached to the 28, but it is the same color and has matching mounting
holes so it probably does.

My question is....does this thing wind up paper that has been printed, or
is it used as an external paper feeder? Is the bar used to trigger the
motor when there is some slack in the paper? 
                                                            Steve