The Crane Capacity Index of a crane is the average value of the lifting load moments in ton/meter at three main boom lengths (minimum, average, and maximum) and their corresponding average reach.
REMARKS
The Crane Capacity Index is based on the maximum boom length, ballast, outrigger positions, etc., as stated in the crane manual.
For telescopic cranes, minimum boom length refers to the length of the boom with all telescopic sections retracted, and maximum boom length refers to the length of that boom with all telescopic sections extended. For cranes with a lattice boom, the maximum boom length is the longest boom length included in the manufacturer's delivery program for that crane type.
The main boom is the boom that carries the main hoist block at its end.
a. If the average reach is not found in the load chart, the load corresponding to the average reach must be arithmetically determined by linear interpolation between the load values corresponding to the next larger and the next smaller reach. b. If the average boom length is not found in the load chart, the average reach corresponding to this boom length is found by interpolation between the average reach of the next larger and the average reach of the next smaller boom length. For the reach found in this way, the load values are determined on the table of the next larger and next smaller boom length. Interpolation between these last two load values then gives the load corresponding to the average reach of the average boom length.
The reach of, for example, a loader or forklift, to which a boom is mounted that cannot slew on the undercarriage, is the distance from the plumb line of the hoist hook to the center of the wheelbase.
The Crane Capacity Index must be calculated from the lifting table that applies to the crane's largest permissible slewing range (typically 360 degrees)
Please note
The maximum load is the greatest load for which overload testing was conducted during the initial inspection and prior to first use.
