A tonneau cover system for covering a space. The system includes a frame having rails. A cover is disposed over the frame for covering the space. A block, a receiver, an anchor and a latch are all coupled to the frame. A mechanism is disposed between the block and the receiver and provides adjustment to the frame by moving the receiver, the anchor and the latch as a unit between an initial adjustment position and a final adjustment position. The mechanism also provides tension to the cover when the latch is engaging the frame.