Enhanced scan of <a href="https://en.wikipedia.org/wiki/E.A._Couturier" class="extiw" title="en:E.A. Couturier">Couturier</a> 1913 patent artwork from US Pat Ofc
<a href="//commons.wikimedia.org/w/index.php?title=User:Rwberndt&amp;action=edit&amp;redlink=1" class="new" title="User:Rwberndt (page does not exist)">Rwberndt</a>
10/30/10
<span class="int-own-work" lang="en">Own work</span>