Abstract: An apparatus for adjustably attaching a cover to an open-topped vehicle enclosure including a cover attachment member, a plurality of cover attachment clip members and a plurality of rail members attached to the top of a side wall of the enclosure by any suitable means. A cover attachment member affixed to a peripheral element of a cover is engageable with the cover attachment clip members, which are engageable with the rail members. The cover attachment member may be attached to the rail member in various different positions to accommodate variations in the cover dimensions.

Abstract: A support frame for a rail-based tonneau cover for open-topped vehicle enclosures, such as the beds of pick-up trucks, is provided having a pivotable portion, for permitting access to the truck bed without removing the cover from the rails. The support frame includes a latching mechanism for releasably latching the pivotable portion. The latching mechanism is itself accessible only upon lowering of the tailgate. A support is provided for holding up the pivotable portion in a raised position. The latching mechanism and the support are interconnected.

Abstract: Tonneau cover apparatus for rail mounted tonneau cover systems for pick-up truck beds and the like are provided. The invention included a spacer member for a accommodating seasonal dimensional variations in covers; adjustable corner connector apparatus for non-rectangular truck beds; improved adjustable snap-type closure members for covers, and an improved snapless cover fastener.

Abstract: A latching crossbar apparatus for supporting a flexible cover for a truckbed cover of the type employing rails which are affixed proximate or on the tops of the side walls of a pickup truck cargo box. The crossbar apparatus includes a latching mechanism for the facilitated installation and subsequent removal of the crossbars from the rails.