Derailleur gears by 13 drive-train. Most road bicycles have two chainrings, and touring bicycles commonly have three. The rear derailleur serves double duty: moving the chain between rear sprockets and taking up chain slack caused by moving to a smaller sprocket at the rear or a smaller chainring by the front derailleur. In order to accomplish this second task, it is positioned in the path of the bottom, slack portion of chain. Sometimes the rear-derailleurs are re-purposed as chain tensioners for single-speed bicycles that cannot adjust chain tension by a different method. Although variations exist, as noted below, most rear derailleurs have
French fry vending machine The unit uses a specially-designed dispenser to prevent the potatoes from being crushed or broken. As of September 2015, only the single prototype is available, which is housed at Wageningen University. Orders are placed using a touchscreen, and a fork and salt are provided separately in a box. French fry vending machine A French fry vending machine is a vending machine that dispenses hot French fries, also known as chips. The first known french fry vending machine was developed circa 1982 by the defunct Precision Fry Foods Pty Ltd. in Australia. A few companies have developed and manufactured French fry