On Dec 12, 6:29*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley 8.3.70:

The non-driven roll would simply stall when the
crank link hit dead-aft-center, and could not be reasonably expected to
advance or retract, no matter which way the driven roll was turned.

BTW... You might argue that there could be another crank link at the
other end 90-degrees out of phase with the one we could see. *That
certainly would solve the "aft-dead-center" problem.

OK... That would work if you turned the front roller with a gear from the
crank, but how would that work with a hand crank arm on one end of either
roller? And if there were a gear turning either, then why use a link? G

Interesting mechanism, indeed! *I think it's one of the few I've seen
where the work is part of the machine.

LLoyd

Lloyd, look carefully! There is a link at both ends of the machine.
One appears to be 90 degrees out of phase with the camera link. Just
like the old steam locomotives! Ingenious!

Paul