Casement window handle
A quick learner from Ludlow Ma says:
May 15, 2016
Gear seems to be ok but handle doesn't catch to open or close window handle says truth patent pending and had # 45191
Paul from SWISCO responded:
May 18, 2016
Hello! Check out our 39-205. I think this will match what you have. Keep in mind this has a spline size of 11/32". If yours does, as well, then this should work.