Looking for patent info for the Russell & Erwin "Columbia" and "Improved Columbia" cylinder locks. Does anyone have any patent numbers or other info for these locks? They appear to be from the 1880's or 90's at the latest. Other than one or two examples, pictures/info is practically non-existent on the web.

I'm interested in the internal workings of these locks. I've seen the keys on eBay from time to time; they appear to be of the push key type, but I'm assuming they are some type of lever or slider mechanism as opposed to the pin tumbler mechanism. Any info is greatly appreciated.