A plurality of pivotably connected slats can be movable between a closed position wherein the slats cover the vehicle box, and an open position. At least one slat can include a first and second end fittings having first and second fixed locking elements, respectively. Each of first and second side rails can include a movable locking element movable between a locked position in which the movable locking elements in the closed position engage an adjacent one of the fixed locking elements to restrict movement of the at least one slat away from each side rail, and an unlocked position in which the movable locking element is disengaged from the adjacent one of the fixed locking elements allowing movement of the at least one slat toward the open position.

A side rail can define an exterior and an interior channel. A coupling strip within the exterior channel of the side rail can be positioned to selectively engage with a coupling strip of a tonneau cover. An end cap can be positioned on an end of the side rail. The end cap having an end face can include an interior extension within the interior channel and an exterior tab extension within the exterior channel between the longitudinal raised side portions. A retaining fastener can extend through the exterior tab extension and can fix the end cap to the side rail without the retaining fastener passing through the coupling strip. The exterior tab extension can limit longitudinal sliding movement of the coupling strip within the exterior channel.

A vehicle includes a truck bed side panel, a top cover, a clamp, and a plug. The truck bed side panel has a top defining a stake pocket and an overhang extending from the top. The top cover has an upper surface defining an aperture. The clamp is secured to the top cover and engages the overhang to secure the top cover to the top of the side panel. The plug is disposed within the stake pocket and aperture to prevent slippage of the top cover.

A tonneau cover system is provided for a cargo box of a pickup truck. The cargo box including a sidewall having an inboard side, wherein the inboard side extends downward and includes a lower edge. The tonneau cover system comprises a framework assembly positionable over the cargo box of the pickup truck and a bed rail extender having an engagement surface. The bed rail extender is adapted to attach to the inboard side such that the engagement surface is spaced downward from the lower edge of the inboard side. A clamp assembly is operably coupled to the framework system. The clamp assembly has an engaging member selectively positioned between a latched position and an unlatched position. The engaging member is adapted to contact the engagement surface of the bed rail extender in the latched position to retain the framework assembly to the cargo box.

A tonneau clamp including a link slidably coupled to tonneau cover; a clamping link pivotably coupled to the link and having a clamping surface; and a handle pivotably coupled to the link and the clamping link and moveable between lowered and upper positions. The handle can be pivotably coupled to the link at a first pivot joint and to the clamping link at a second pivot joint. Handle movement causes the clamping link to pivot relative to the link to raise the clamping surface from an unclamped position to a clamped position in which the clamping surface applies a clamping force against the underside of a ledge of a vehicle cargo box. In the unclamped position the first pivot joint is on a first side of a line and in the clamped position the first pivot joint is on a second side of the line opposite the first side.

A threaded rod can be pivotably coupled to the tonneau cover via a proximal end. A housing can have first and second housing portions slidably coupled to the threaded rod and moveable along the threaded rod relative to each other between locked and unlocked positions. The second housing portion can include a channel positioned to receive a downwardly disposed distal edge of an inboard flange. Locking pawls within the housing can move to engage threads of the rod to prevent movement of the channel relative to the elongate member when in the locked position. The locking pawls can move to release the threads of the rod to allow movement of the channel relative to the rod when in the unlocked position. A biasing member can apply a biasing force biasing the housing toward the proximal end of the elongate member and biasing the housing toward the locked position.

A side rail can define an exterior and an interior channel. A coupling strip within the exterior channel of the side rail can be positioned to selectively engage with a coupling strip of the tonneau cover. An end cap can be positioned on an end of the side rail. The end cap having an end face can include an interior extension within the interior channel and an exterior tab extension within the exterior channel between the longitudinal raised side portions. A retaining fastener can extend through the exterior tab extension and can fix the end cap to the side rail without the retaining fastener passing through the second coupling strip. The exterior tab extension can limit longitudinal sliding movement of the second coupling strip within the exterior channel.

A vehicle includes a truck bed side panel, a top cover, a clamp, and a plug. The truck bed side panel has a top defining a stake pocket and an overhang extending from the top. The top cover has an upper surface defining an aperture. The clamp is secured to the top cover and engages the overhang to secure the top cover to the top of the side panel. The plug is disposed within the stake pocket and aperture to prevent slippage of the top cover.

A tonneau cover access panel assembly connectable to a tonneau cover assembly that eliminates the need for side rails to both locate and tension the top cover. The tension works to seal out environmental elements and holds the tonneau cover and locating bows of the tonneau cover in place. The tonneau cover access panel holds the rear of the tonneau in the closed tension state keeping the tonneau secured and tight until the cover is opened by an operator. The tonneau cover access panel assembly is movable between a closed position and a fully open position, and, is movable between at least a first open position and the closed position for more limiting access to the cargo bed of the vehicle when desired. The tonneau cover access panel assembly also reduces weight and complexity.

A threaded rod can be pivotably coupled to the tonneau cover via a proximal end. A housing can have first and second housing portions slidably coupled to the threaded rod and moveable along the threaded rod relative to each other between locked and unlocked positions. The second housing portion can include a channel positioned to receive a downwardly disposed distal edge of an inboard flange. Locking pawls within the housing can move to engage threads of the rod to prevent movement of the channel relative to the elongate member when in the locked position. The locking pawls can move to release the threads of the rod to allow movement of the channel relative to the rod when in the unlocked position. A biasing member can apply a biasing force biasing the housing toward the proximal end of the elongate member and biasing the housing toward the locked position.