Abstract: An articulate bridge assembly covers an enclosure transport pathway from an enclosure feeder through an enclosure pick-up station in a reciprocating ram type envelope inserter. The bridge includes a cover hinged along an axis parallel to the transport pathway. The horizontal and vertical planes of the cover are stabilized with reference to the inserter frame by spring mechanisms incorporated in the cover hinge assembly. A switch for detecting multiple enclosures in the pathway is mounted to the cover. To adjust the switch for various enclosure thicknesses, a knob at the face of the inserter is rotated. The knob advances a lead screw against a sloped surface of a pivot link. The pivot link in turn bears against a bracket assembly carrying the switch. The upper surface of the cover is planar and obstruction free, while a chassis is carried by the undersurface. Mounted to the chassis are skis which urge successive enclosures against transport belts.