Closing mechanism

The markings on this window are, a triangle with AW inside of it, on the left is the letter M on the right is something that looks like parentheses {} right underneath it is E6,at the bottom of the triangle is a V circled with 4 quarter round lines.

Also the corner of the cover is broken, this may be why the mechanism does not shut the window, or maybe wear and tear as it does not bite the wheel.