You guys are really something.
I found it with your help and was preparing to add a link--and find that I have been bested by a few hours! It seems that the Spofford patent was an improvement on the chuck that had been in production for just over two decades.
The first Spofford patent was Nov 1, 1859, a month and a day before John Brown was hanged--just to give it some historical context. A long time ago.
Thanks again for all the help.