A new web page about the Hickman grand piano action is under
development at the MMD Tech site.  Image files of all the pages
of the patents are available.  Visit

http://mmd.foxtail.com/Tech/index.html
  'Pianolas' & Pianos: Hickman Grand Piano Action
  http://mmd.foxtail.com/Tech/HickmanAction/index.html

MMD articles about Clarence Hickman and his work are indexed at
  http://mmd.foxtail.com/archives/KWIC/H/hickman.html

The letters of Clarence Hickman, compiled by MMDer Jim Brady,
are especially interesting.  The series is introduced in
MMD 1999.07.21.02, "Clarence Hickman Letters".

Robbie Rhodes