Stepped Pulley : A belt pulley (or series of pulleys) of differing diameters mounted on a shaft. When the belt is shifted from one 'step' to the next, the speed ratio between the driving and driven shafts is changed
Ministry of Business, Innovation and Employment, Glossary of terms and acronyms, Wellington, New Zealand 2010. http://wwwsosh.govt.nz/resources/glossary-u.shtml, (Occupn Hlth and Sfty - Brit) {530}