Pushing down on the ball and lever pulls on the light-colored belt and unwraps it from around the pulley axle. The dark-colored belt winds on at the same time. The large pulley spins and the endless belt drives the blower.
On the up-stroke, a ratchet hub on the pulley shaft allows the big pulley to continue to spin while the light-colored belt winds up again. The dark-colored belt acts as a tether and limits the up-stroke so the other belt won't wind on too far but I'm not sure that's original or neccessary.
I think parts are missing. I suspect there was a spring to do the up-stroke. And the position of the ball and lever is way too low even for short guys to pump it comfortably so I'm guessing that there was some kind of lever mounted higher or foot pedal hung below.
Anybody ever see one of these complete? Know what the original arrangement was?