Patent ID: 7231188

Claim:
A mechanism for rotating at least a first and a second housing element of a device with respect to one another, where the first and second housing elements have a common axis of rotation, which is substantially perpendicular to a front surface of the device, the first housing element having a rounded surface which extends at least partly around said axis of rotation, said mechanism comprising: a wheel having a rounded outer edge for engaging the rounded surface of said first housing element, said wheel being coupled to said second housing element at a center point about which the wheel is adapted to rotate, and for traveling around the rounded surface of the first housing element along with the corresponding center point as the wheel rotates, said wheel additionally having a contact point offset from said center point; a tension device having a relatively fixed end and a relatively free end with respect to said second housing element, said tension device being adapted for supplying a force when said tension device is preloaded; and a linkage coupled between the free end of the tension device and the offset contact point of the wheel for biasing the wheel toward rotation.