screen door handle.
A handy person from Evanston, IL says:
April 19, 2014
Here's the broken screen door handle
Dave from SWISCO responded:
April 24, 2014
Thank you for posting! I've seen this lock before. Unfortunately, we do not have an exact replacement for it. The closest match we have is our 84-223. Now, I cannot guarantee that this will work without some retrofitting, but it is the only possible solution I can think of.