Brownie 500 a-5 projector

I have a brownie 500 model a-5 projector that I believe is missing a part. I am trying to find out what the part looks like. The part, I believe, is a spring that connects to two sides a metal part that has film forks on it. The fork is at the front of the part and engages the film sprocket to advance it. It is right below the lens. The back of this part looks like it needs a spring type device between it that keeps the part ingaged on a cam that is part of the manual feed knob. Does anyone know what this "spring" part is, what it looks like, and if there might be something I can use in its place? Thanks