My father and grandfather patented this masonry hammer in 1935, while they were living in Baltimore, Maryland. I just came upon Google's Patent Search and looked up their names, Arthur J. Richardson and Edward J. Richardson. Voila - their patent popped up immediately: HAMMER - Richardson et al.
An interesting bit of trivia is that I see my father was using only the initial "J" for his middle names. His full name on his birth record was "Edward Arthur James Richardson." I am posting it under "technology," although that does seem a bit odd for a hammer in today's computer world. But ... it was something new, wasn't it? A new technology for masonry?
Those ever-inventive Richardsons! What will they think up next? See A Richardson Grandson.
The image, Richardson Hammer, was originally uploaded by barneykin. It is posted here from Barneykin's FLICKR account.