On snack machines that have snacks nestled between loops of a coil, the coil is adjusted differently for candy bars than for snack cakes and potato chips. If you look carefully, you’ll notice that the coil is rotated further around for candy bars so that there’s more of the coil’s end looped around to hold the candy in place. Because potato chips and snack cackes have more bulk, there’s less likelihood that they’ll slip out and become inadvertently free snacks.
You can read a bit about the history of vending machines here.
If MacGyver taught us nothing else, it was that it used to be possible to pour salt water into vending machines to get free drinks.
In Japan in 1993, school girls’ panties could be purchased from vending machines for the equivalent of US $50. I wonder what the coils in those machines are like.
According to one source, “Every 15 minutes, over 3.5 million coins are inserted in vending machines located in the United States alone.”