As far as I can figure. The handle has a pop-out winch that you use to wind the blade out. I love that brass worm gear. I wonder what the wind-up ratio is? From the looks of it I would hazard a guess that it would take 16-18 revolutions to fully extend the blade. Still that is soo awesome.

Wind-up Pocket Knives by Alexander Flood
Photo: Sam Dunne (1225 views)

via NEW DESIGNERS 2013 – Wind-up pocket knives – Alexander Flood – Core77.

Alex Flood, Sheffield Hallam University – adrflood@gmail.com