US Patent 7320152 Self-latching hinge assembly

A hinge assembly includes a main member having a main cam member and a bore extending generally along an axis of rotation. A pivot member, fixed to an end of a shaft extending through the bore, includes a pivot cam member and is rotatable with respect to the main member. At least one torque element is rotatably engaged with the shaft and is substantially rotationally fixed with respect to the main member. The at least one torque element imparts a first frictional resistance to the shaft with rotation of the shaft in a first direction and a second frictional resistance to the shaft with rotation of the shaft in a second direction. The first frictional resistance is greater than the second frictional resistance. Interaction of the main cam member with the pivot cam member assists in maintaining the hinge assembly in at least first and second positions.