Flat Belts

Flat rubber belts were developed around the turn of the century primarily as replacements for leather belts. With the advent of V-belts, fewer machines were designed to use flat belts, and their production became largely a matter of supplying replacement parts. Recent developments in flat-belt technology have overcome their previous drawbacks of high tension and mistracking. New designs and advances in materials have made both low and high-power transmission practical and cost efficient, and at speeds that usually exceed other belt designs. This type of flat belt is used where minimum vibration is required at the driven pulley. Maximum damping requires tuning the spring rate of these belts. In addition, semielastic belts have many features of unsupported stretch belts while maintaining a fabric substrate for support. Semielastic belts do not require pulley take-up or adjustment, easily work in sets, work well over a wider length tolerance, and are relatively inexpensive in high volume. Because of these features, many OEMs are able to simplify and compact otherwise complicated designs. Over the past few years, a high volume of semielastic belts have gone into machines for the banking industry, copiers, computer disk drives and peripherals, and office equipment. Most of these designs use a wide variety of small multipulley precision drives. Nonstretch endless flat belts also deserve consideration, especially in applications where small pulleys, high speeds (10,000 to 15,000 fpm), or both are involved. Because endless flat belts can be made very thin, 0.015 to 0.062 in., they are not as susceptible to centrifugal loads at higher speeds. Flat belts also are less costly than gears when teamed with small high-speed motors, especially when a compact package is important. Typical applications generally involve motors of 1 hp or less and speeds to 10,000 fpm. Developments here include sticky yet abrasion-resistant rubber compounds that