Continuing adventures with Sholes Visible #4004 ...
I had to remove the carriage in order to get good access to the mechanism. It's not too hard -- you unscrew a couple of big nuts and a few small screws, unwind the mainspring until there's no tension, and remove the drawband from the carriage. Then the carriage lifts off. You can also separate the lower and upper parts of the carriage just by moving two levers aside.
Now the fascinating backside of the Sholes Visible mechanism comes clearly into view.
It's an industrial work of art that reminds me both of Klimt and of "Metropolis."
When you depress a key on the keyboard, one of these lasso-like pieces will move down. The little levers that protruds through the diagonal slots are connected to the horizontal rods/typebars (seen on my previous post). So when the "lasso" moves down, the rod will first be pushed toward the center, then pivoted so that the typebar goes up and hits the platen. When the parts are clean, this all happens very fast.