Vending Machine

Vending Machine, machine that dispenses food, drinks, chewing gum, toiletries, or some other type of merchandise when money is inserted. Modern vending machines can accept coins and paper money, and some accept prepaid tokens. Some simple vending machines require that the exact amount of money for a particular item be inserted, but an increasing number of vending machines can make change.

The earliest vending machine was described by Hero of Alexandria in the 1st century ad. A coin dropped into this early vending machine struck a lever, causing a valve to open, which would allow a certain amount of holy water to flow out of the machine. During the 18th century, simple vending machines were used in England and the American colonies to dispense snuff and tobacco. The first chewing gum dispensers were placed on New York City train platforms in 1888. By the time World War II ended in 1945, vending machines dispensing a variety of merchandise could be found throughout the United States. Currently, vending machines can be found not only in the United States, but throughout the world. In the United States, vending machines mainly supply food and are found in hotels, transportation terminals, and institutions. In Europe and Japan, where they are used to supplement the services of retail stores after regular business hours, they carry more varied merchandise.

Some types of modern vending machines are cooled to keep food within the machine from spoiling; others are heated to keep food warm. Vending machines dispense merchandise in a variety of ways. In some vending units, such as soft drink or candy machines, pulling a selector rod, or pushing a button releases the item into an access tray. Other machines have small compartments with door flaps that can be opened after the correct amount of money has been inserted. Some vending machines perform a series of tasks to prepare a beverage, such as a cup of coffee, or a cooked meal, then present the finished product to the user.

An important component of vending machines is the mechanism that accepts and determines the value of inserted money. When coins or tokens are inserted a series of tests determines the dimensions, weight, electric properties, and magnetic properties of the money; a coin or token that fails any test is rejected. If the coin or token is accepted, its value is determined from the data acquired through the tests. Paper money is also carefully tested to ensure that it is not counterfeit. One type of mechanism used to check paper money uses a magnetic-sensing device to scan the length of the paper money. Ink used to print dollar bills has a small amount of metal in it; as the bill passes across the magnetic-sensing device, the device records the magnetic signature of the bill, and a computer compares the scanned pattern with the pattern of real paper money. If the patterns match, the bill is accepted. Some mechanisms can differentiate between paper money of different denominations.