Patent ID: 6253983
Filing Date: 2001-07-03
Classification: B65H,D21G

Abstract:
An apparatus for guiding a running web comprising:at least two guide rolls, which includes at least one driven roll;a suction box coupled to a vacuum source and comprising a wall having an aperture;an air-permeable belt tensioned over said at least two rolls;said suction box being positioned within loop formed by said belt;said suction box being positioned to suction a portion of said belt that is adapted to guide the running web;a vacuum control adapted to control a degree of vacuum in said suction box and comprising a movable element positioned adjacent said aperture and an inner surface of said wall, said moving element being adapted to open and close said aperture;an actuator being coupled to said movable element to effect at least one of the opening and closing of said aperture;a stationary element located within said suction box;a pressure source; anda control line;said actuator comprising an air bag positioned between said stationary element and said movable element;a control valve adapted to adjustable establish a substantially constant pressure in said air bag; andan interior of said air bag being coupled to said pressure source through said control line.