Preface When most people hear the word “chain,” they imagine a short-link chain, which consists of connected metal rings, or the type of chain used on a motor- cycle or bicycle. However, chains of every size and description are used in factories, even though they are rarely seen in daily life. In fact, most people probably don’t notice that chain is being used all around them, in parking ele- vators or escalators, for example. Steel roller chain, which is the ultimate in chain design, and constitutes the majority of chain produced today, is a relatively new invention. Its history is only about 100 years old. It is newer as a machine part than gears and belts. In Japan, the first chain was imported with bicycles during the Meiji-period (1867~1912 A.D.). Domestic production started when the supply from the United States and European countries was stopped during World War I. There are two functions of chain: power transmission and conveyance. For transmission roller chains, Japanese chain makers gradually changed the prior- ity of production from bicycle chain to industrial chain. After World War II, these chains challenged the advanced chain from the United States and Europe. Now they have achieved the highest levels in the world for both qual- ity and quantity. This holds true for conveyor chain, as well. The industries that are the main users of the chain, including automobile, electronics, steel, chemical, environmental, food, bicycle, and motorcycle industries, have developed new technologies and production methods that require various high performance chain. These industries are looking for improvement in tensile strength, fatigue strength, abrasion resistance, environ- mental resistance, and efficiency, as well as perfection of maintenance-free chain products. To satisfy these many requirements, chain makers are making every effort to improve chain’s basic performance step by step. In addition, new chain technologies, including rolling bearing systems, super engineered plastic, and free flow chains, are being developed. Because of these two fac- tors, chains with special characteristics are now being produced. During his lifetime of experience, the editor of this book has helped to develop most of these new types of chain. He has also acquired a great deal of practical knowledge through his contacts with end users. Accordingly, this comprehensive book explains the points that readers may want to know, including the most important point: determining the quality of the chain. I hope this book can always be with you when you use chains. I’m afraid some of the descriptions in this book may be either inadequate or hard to understand; therefore, I hope that readers will point out any mistakes and send me their comments and input. Furthermore, because this book is
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