How does the ball return work on a coin-operated pool table?
If you have ever played one of those coin-operated pool tables in a place like a restaurant or an arcade, then you know that the obvious question is, “how the heck does this thing return the cue ball to me???” If you look inside the table, there is a system of chutes that connect to the six pockets on the table. Each chute sends a pocketed ball from the pocket to a collection chamber, where the numbered balls are lined up single file. These numbered balls remain locked in the chamber, which you can see behind a piece of Plexiglas, until someone wants to play a game and inserts some coins. Of course the cue ball can’t get stuck in this chamber — If a player accidentally pockets the cue ball (a scratch), the cue ball needs to come back out. Table manufacturers needed a way to allow the cue ball to be returned to play, while keeping the pocketed numbered balls locked in the storage compartment. Many solutions have been proposed to solve this problem, including: • Light sensors that sense
