Need a part for a jalousie window.

I have included a photo of an intact part and a photo of the broken part. I have also included a photo of the window. I am sorry, I do not have part numbers or names. I believe these are original windows and if so, the house was built in 1979. Upon cranking the window open yesterday, the plastic part that helps the window hinge move up and down broke. I need one. Thank you. Lynn Keller