Abstract: The roller of a truck box roller tarp assembly is equipped with dependent loops of chain at spaced intervals along its length. Brackets, forming hooks, are secured to the truck box at a common elevation along one side. When the tarp is closed over the box opening, the roller loops hang below the hooks. The roller may be reverse rolled, using the conventional crank, to climb the tarp and bring the loops into engagement with the hooks. The now-constrained roller may be further reverse rolled, to tighten the tarp. The roller is then locked up by securing the crank to the truck box in conventional fashion.

Abstract: A collapsible, articulated structural section which is movable between a stable erect configuration and a collapsed configuration includes a manually actuable positive lock for locking the device in its erect configuration. Four pairs of scissored links connected to exterior pivots at their ends form the exterior of the section, and the interior is formed by a pair of face pivots and four pairs of crossed, but unconnected, face links, each pivotally connected at one end thereof to an exterior pivot and at the other end thereof to a face pivot. A through-extending opening is provided in one face pivot, and a locking component including a shaft portion insertable into the opening, and a rotatable locking member mounted on the end of the shaft, are mounted on the other face pivot.