US Patent 7116356 Vertically self-aligning camera mount apparatus

A self-aligning apparatus comprising a ball bearing assembly mounted on a base plate and supporting an axle on which is mounted a video camera. In response to the force of gravity, the axle rotates such that the camera maintains a line-of-sight parallel to the cable of a crane or similar heavy equipment such that the video camera constantly views the work site of the hook element of the equipment. The equipment operator can view in real time images transmitted by the camera there reducing dependency on ground observers and improving safety.