Fixed guide bar for tensioned webs and bar guide assembly utilizing such guide bars.

摘要

Noise-causing vibrations in the span of a tensioned web (7) running over and away from an arcuate guide surface area (14) of a circular perimeter fixed guide bar (12) at a speed such that in the off-running angle between the web and the curved perimeter of the bar, air moving in the direction of the web in such angle would tend to follow the curvature of the bar (Coanda effect) and cause splitting of the air between the web and the bar, are inhibited by locating a spoiler (19) in a plane extending substantially tangentially from the off-running side of the arcuate guide surface area (14). The spoiler is in the form of one or more ribs providing a surface in the tangential pane. Where the web span runs between two spaced fixed circular perimeter bars (12, 13), a spoiler (21) may also be located in a plane extending substantially tangentially toward the onrunning side of the arcuate guide surface (15) of the bar (13) located at the downstream end of the span.