Hinge assembly for tonneau cover

In a pick-up truck having a forward cab and a rearward cargo box that is covered by a hard tonneau cover, a hinge assembly for pivotally attaching the hard tonneau cover to a side wall of the cargo box comprising:

• a tonneau bracket that is secured to the tonneau cover,
• a mounting bracket that is secured to the side wall of the cargo box,
• a hinge link that is pivotally attached to the tonneau bracket at one end by a first pivot and to the mounting bracket at an opposite end by a second pivot,
• a control link that is pivotally attached to the tonneau bracket at one end by a third pivot that is spaced aft of the first pivot and that is pivotally attached to the mounting bracket at an opposite end by a fourth pivot that is spaced aft of the second pivot,
• the hinge link being longer that the control link and having a boomerang shape,
• a Y or T shaped pivot aim that is pivotally attached to the mounting bracket by a fifth pivot that is below the second pivot and the fourth pivot, the Y or T shaped pivot arm having an upper forward branch and an upper rearward branch,
• a drive arm that is pivotally attached to the upper forward branch of the pivot arm by a sixth pivot and that is pivotally attached to the tonneau bracket by a seventh pivot whereby the tonneau bracket and cover are moved between a closed position and an open position by rotation of the pivot arm and
• a gas spring that is attached to the mounting bracket and to the upper rearward branch of he pivot arm for biasing the tonneau bracket and cover toward the closed position.