Abstract: A boom apparatus for use in lifting and transporting a payload includes a boom pivotally mounted on a support structure and including base and outer boom sections, the outer boom section being telescopically received within the base boom section and being movable axially relative to the base boom section. Sensors are provided for sensing the total length of the boom and the total moment load experienced by the boom, and an electrical warning and control circuit generates a warning signal either when the load as sensed is greater than a first predetermined value and the total length of the boom as sensed is less than a predetermined length, or when the load as sensed is greater than a second predetermined value and the total length of the boom as sensed is greater than the predetermined length, the second predetermined value of the load being less than the first predetermined value.

Abstract: A color coding system for correlating the stages of a multiple stage, telescoping boom with the corresponding sections of a load chart and boom extension chart. The charts are arranged in separate sections which indicate, for various positions of the boom, the angle of the boom with respect to horizontal, its effective horizontal moment arm, and the maximum load that it can safely handle. The boom stages are each provided with a different exterior color, and the chart sections are colored such that each section is correlated with the boom stage to which it corresponds. Since the colors of the boom stages that are extended are readily visible, the color coding system facilitates reference to the proper sections of the charts and decreases the possibility of human error in reading of the charts.