It's a clutch gear. You can use it instead of a pair of pulleys with a rubber band if you want to avoid stalling your motor if something jams. Compared to the pulleys, it gives you a very well defined stall torque - it's actually printed on the (...) (25 years ago, 14-Sep-99, to lugnet.robotics)
(...) Yes, exactly. In fact, I'm in the midst of building a robot vehicle which uses this for collision detection, instead of having some sort of feeler/bumper system. (25 years ago, 15-Sep-99, to lugnet.robotics)
