Pulley for forms feed tractor

摘要

A tractor for feeding perforated paper has an endless belt of flexible material having pins and teeth extending in opposite directions from said belt. The belt has more rigid sections corresponding to the locations of the teeth between flexible web sections. A pulley is provided which has curved sections and grooves for receiving the teeth of the belt. The curved sections comprise an arc with ends having points of tangency with planes of straight sections of the belt extending across the grooves. The curved sections may comprise a composite arc having end arc sections with points of tangency with the planes of the straight sections of the belt and a center arc section having points of tangency with the end arc sections. The curved sections may also be an arc which has a continuously increasing radius of curvature from the points of tangency with the planes of the straight sections of the belt to a center line between the grooves.