No Gear is an Island

This article discusses Coin Acceptors Inc.’s designs and manufactures’ vending machines, control systems, bill acceptors, and coin changers for the snack and beverage industry. The company, based in St. Louis, sells its products through branch companies as far away as Europe and Australia. To improve the industry’s machines, the firm set out to offer a high-capacity coin changer, which would operate a bit differently. It was during the design of this device that our engineering team at Coin Acceptors was reminded of an important design principle: No gear operates alone. With the production date for their coin changer looming, they needed to come up with solutions fast. The company decided to bring the design in-house. Load analysis suggested a benefit from a material change for the ring gears. They chose a reinforced nylon from Ticona of Summit, N.J. The material offers more strength without increasing wear. It also has a reduced coefficient of thermal expansion, which meant 25 percent less fluctuation in backlash and contact ratio throughout the wide operating temperature range.