The only marks I can make out are
Pat’d Dec 6 1884
Pat’’d May 24 1870
Bartholomew Cheap Ratchet Brace photo is reposted with the permission of wkfinetool.com
Some More information.
http://www.wkfinetools.com/hUS-borTools/bartholomew/barthol-index.asp
http://www.sydnassloot.com/Brace/Bartholo.htm