My wiper arm keeps falling off

I went out and looked on my car. It is a 70 Dart. Don't know if they are the same or not but here is what I saw. Just about every thing has a clip of some kind. Except one connection. One arm goes through a shaft. There is no clip on this shaft holding it together. The end of the shaft is mushroomed out to hold the shaft on. Is that what you are talking about?