How are vending machines designed?

Sublimation of ancient physical knowledge

-1700 The use of vending machines can be said to be the symbol of our times. The earliest vending machine was designed by Herod, a Greek scientist in Alexander's time. He invented this device to give holy water in temples. This vending machine is a kettle with a short outlet pipe at the bottom. The water inlet of the pipe is in the pot. There is also a small stick in the pot, which can rotate like a seesaw on the pivot. A piston hangs from one end of the piston rod. Usually, the stick is kept horizontal, and the piston just blocks the water inlet. If you put a coin through the slit above the kettle, the coin will touch the other end of the stick, so the stick will tilt, lift the piston, and water will flow out of the outlet pipe and pour into the glass. When the coin fell to the bottom of the pot, the stick returned to its normal state and cut off the water flow. Now, simpler coin-operated machines, such as candy vending machines, are made by similar principles.

The genius hero invented many things. From his many works on mechanics and engineering, we can see that his thoughts include scientific practice and living room magic.

The automatic log designed by Hero is considered as the earliest counting device. It is an odometer with wheels and a turbine, which is installed in a box on the carriage. His automatic diary occupies an important page in the history of machinery.

Hero also made a measuring instrument, which can measure the angle and correct the level. It attracts people's attention, not only because it is more accurate than earlier instruments, but also because it has interchangeable parts.

In addition, he invented the press and crossbow for squeezing olive oil and grape juice, and described in the book how to make musical instruments sound with an air pump. Most of his inventions are designed to entertain guests or impress admirers. Hero has made many automation devices operated by ropes, such as singing mechanical birds and puppet shows that pull up the curtain. What's more, he uses steam or hot air to drive parts. He invented a steam turbine called a spinning ball. Steam enters a hollow ball and then is ejected from a pair of nozzles on the symmetrical side of the ball, so the hollow ball runs under the thrust of steam. This device proves the power of steam, which predates the appearance of steam engines 1700 years.

Hero's most amazing design is a model temple. The switch of the temple gate is indirectly controlled, which makes the audience feel very mysterious. The altar is hollow. When the altar is ignited and heated, the air in the cavity will be heated and expanded, and a living rod will be pressed down. After being pressed, the water in the lower container will flow out of a tube and into a bucket, so that the bucket will sag and drive the rotating shaft of the door connected with it to open the door through the rope. The fire in the altar goes out, the air in the cavity contracts, the water is sucked back into the container, the weight of the bucket is reduced, the counterweight falls, and the door is closed.

We don't know how many successful designs Hero has. But the pictures and descriptions of these ideas recorded in his book undoubtedly show that he is many centuries ahead of his time.