What components does the boom angle indicator consist of?

The boom angle indicator consists of a pendulum and a numbered scale because this design allows for accurate measurement of the boom's angle relative to a reference point, typically vertical or horizontal. The pendulum reacts to the boom's position as it moves, providing a direct visual reference on the scale, which is calibrated to reflect the angle in degrees. This system is essential for operators to ensure safe lifting practices, as knowing the precise angle helps prevent the crane from exceeding load limits and contributes to overall stability during operation.

The other components listed, such as cables, hooks, sheaves, drums, pulleys, and winches, are related to the crane's lifting mechanics but do not serve the function of measuring the boom angle directly.