ABSTRACT
Select a brake for a crane rated for a maximum load of 2800 kg as limited by the load rating for the 19×7 nonrotating wire rope used. The rope diameter is 21 mm, its weight is 2.069 kg/m, and the maximum drop of the cable is 30 m. The grooved cable drum is 0.50 m in diameter at the base of the grooves, weighs 696 kg, will accept 20 turns of wire rope, and has a radius of gyration of 0.23 m. The drum is driven by a gear train, illustrated in Figure 9 for which the gear data are as follows: Gear number Pitch diameter (m) Radius of gyration (m) Mass (k) 1 2.00 0.81 1278
Four turns remain on the drum when the load is 30 m below the top of the crane. The rope length from the drum to the top of the crane, Figure 10 is 21 m. Motor speed is 485 rpm, and a descending maximum load is to be stopped within 2.00 seconds after the brake is applied. The motor is disengaged by means of a clutch immediately before the brake is applied.
