Full definition
Power transmission system using a flat (rectangular cross-section) belt running on smooth, slightly crowned, or lagged pulleys. Capable of the highest speeds of any belt type — up to 100 m/s — with excellent efficiency (98-99%) due to minimal bending stress and hysteresis losses. Modern flat belts use polyamide (nylon) or polyester fabric with polyurethane or rubber friction covers, providing high tensile strength in a very thin profile (0.5-3 mm). Belt widths from 10 mm to 1,000+ mm. The crowned pulley (slight convex curvature, typically 0.5-1 mm crown per 100 mm face width) automatically centers the belt. Applications: high-speed textile machines, paper machines, generators, fans, centrifuges, and packaging equipment. Standards: DIN 111, ISO 22. Brands: Habasit, Siegling (Forbo), Gates, Ammeral Beltech. Tracking relies on crown and proper alignment.