Ninety degree turn-up apparatus

The present invention provides a device for turning flat articles, such as envelopes, from a horizontal orientation to a vertical orientation as the articles are transported along a path from an entrance location to an exit location. The device comprises a pair of entrance pulleys, each of the entrance pulleys having an offset crown and rotating on a stationary horizontal axis, and a pair of exit pulleys, each of the exit pulleys having a centerline crown. The entrance pulleys are located longitudinally and vertically apart from one another such that one of the entrance pulleys functions as lower entrance pulley and the other entrance pulley functions as an upper entrance pulley, with the upper entrance pulley being located downstream from the lower entrance pulley. The exit pulleys rotate on a stationary vertical axis. One of the exit pulleys is located downstream from an upstream one of the exit pulleys. The device further comprises first and second flexible, endless belts. The first belt is wrapped around the lower entrance pulley and the upstream exit pulley. The second belt is wrapped around the upper entrance pulley and the downstream exit pulley, wherein the first and second belts complete a 90 degree twist from the respective entrance pulley to the respective exit pulley such that the first and second belts each have a contiguous span for approximately the entire 90 degree twist against which a corresponding span of the other belt applies a normal force.