| The innovation of the Italian Arturo Caprotti replaces the old slide-valve
system with a device, borrowed from the internal combustion engines, which
opens poppet valves
controlled by cams on a camshaft. The steam is hereby very
precisely introduced into the cylinders and easily variable over a wide area.
The camshaft is provided with thread-like slots, as you can see on the pictures
below, that changes the cams position on the camshaft in the very same way as
the eccentric does in the
thread system from 1867.