Your mom was cool!
I can only guess that the bike is a Schwinn. I am led to think so from the three-circle chainring and the long head-tube.
MAYBE some of the knowledgeable old-timers are still hanging around the Schwinn forum. Post your pic at
http://www.schwinnbike.com/heritage/....php?forumid=4
See if any of those cats can identify the bike for you. Wouldn't it be neat if you had your mom's bike now?