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FOREWORD

The original design of precision roller chain dates back to the late1 890s, although various types of drive chains have been in use for centuries. The early automobiles used roller chain extensively as the final drive.T he industrial use for roller chain grew substantially, resulting in the desirability of standardization. The perfected American Standard Chain of today has evolved to meet the demand for ever increasing horsepower and higher speeds as well as accurate timing.

In 1913 the Society of Automotive Engineers published formulas for calculating the roller chain length, sprocket tooth profiles, and other important design criteria. Recommendations from the Roller Chain Committee of the American Society of Mechanical Engineers followed in 1917 with dimensional standards for the various components and assemblies. Early in 1920, through the cooperation of these two groups, roller chain standards were formulated and recommended for acceptance by industry. The progress was followed in 1921 by organization of a sprocket committee of the American Gear Manufacturers Association.