Abstract: A mobile aerial lift having a vehicle of the type having a frame with a longitudinal axis and ground-engaging wheels carried by the frame. An operator's driving station is carried by the frame. An aerial lift is carried by the frame and includes a boom structure and control means for the boom structure which permits the outer extremity of the boom structure to be raised and lowered about a horizontal axis, rotated about a vertical axis, and extended and retracted. A mast is provided for carrying the boom structure and is secured to one side of the frame and is spaced from the longitudinal axis of the frame.

Abstract: A mobile aerial lift having a vehicle and a boom structure mounted on a vehicle. The boom structure has an outer extremity. A workman's basket is mounted on the outer extremity. A control is carried by the boom structure and is accessible to the workman's basket for controlling operation of the boom structure. The boom structure has an insulated boom section and an exclosed space is provided for at least a portion of the insulated boom section. Gas is supplied under positive pressure to the enclosed space and provides a clean, relatively moisture-free environment for a portion of the interior of the insulated boom section and maintains the electrical insulating properties of the insulated boom section.