Walter A. Sheaffer inserted a
side lever into the barrel. It holds a metal bar in the inside. When pulling the lever,
this bar is pressed against the pen sac.
This was one of the most succesfull filling systems from 1912 to the
early 50ies.
21 Shows the Lever as it was used by Sheaffer
22 The Leverbox introduced by Waterman
23 and 24 A back lever as it has been made by Crocker and Matador
