Ok, I'm building a motorized projector screen, almost exactly like this: http://www.youtube.com/watch?v=GgIqx-iKNcw , except on a much larger scale. The actual screen will be made out of blackout cloth (what the back of curtains are made out of), and the screens construction will be similar to this: https://www.instructables.com/id/Cheap-DIY-100quot-Projector-Screen/ . The screen's size will be somewhere around 20x20 (feet), because it will be used in a fairly large auditorium. The screen will hinge up and reside (when not in use) above the stage. The top of the screen will have some hinges attached, so the screen can "fold up" into the ceiling. Toward the bottom, on the back of the screen, there will be a steel cable attached to the frame. This steel cable will be fed into an electric winch, which will be mounted on the ceiling. So, when the electric winch is activated, the screen will either hinge out, or it will hinge up into the ceiling. I know its hard to understand, I've done all the explaining I can. Ask questions if you have to. Anyway, the problem is this: What if this steel cable broke/got frayed and snapped/got chewed up by a darn rat, etc? The projector screen would come hurtling forward, knocking out anyone in its way. So, I need something that limits the speed that the screen can be lowered. I need some kind of hinge that limits how fast the screen can be lowered, so if the cable does snap among other things, the projector screen will make a graceful descent and people will have enough time to get the hell off the stage. Now, Do I think the steel cable is going to snap? Hell no. In fact, the steel cable I'm planning on using will handle over 1000 lbs. The total weight of the projector screen? Maybe 70 Pounds, at the most. These speed limiting hinges are just for that "extra" step of safety. So, does anyone have any suggestions?