What is this?

We spent a week at a beach house.  In the photo, you see a device attached to a door. There were several of them attached to doors throughout the house. It's a hollow steel ball attached to an arm, which was attached to the door. It could move back and forth like a pendulum, but it rubs against the door and doesn't move freely. You can see the rub marks on the door. So it didn't swing by simply opening or closing the door. This photo was taken in 2003 and I still don't know what it is or what purpose it served. If you know what it is, please leave a comment.

Picture of What is this?
jimc45676 years ago
A very long time ago I remember seeing a screen door slam preventer. The ball was made of rubber though, not steel. Screen doors had springs to close them, and not the hydraulic closers they do today. When someone would exit the door in a hurry the door would get moving. As the door closed the ball would rotate out preventing the door from slamming. Here's the only product I was able to find. You'll need to scroll down in the window to see it properly. http://www.rusticworkbench.com/product_pages/doorball.htm
Give that man a best answer. You are exactly right. They are sometimes mounted on other doors so that kids closing them fast would not slam them or get their fingers caught.
jimc45676 years ago
Do the balls mount of he opening side of the door, and not the hinge side? This one appears to be mounted high so as not to obstruct people entering or leaving the room. Is this correct?