Page 5 - SuperLift-DataBook-Sheave-Blocks-SBEDN9

REEVING OF SHEAVE BLOCKS When reeving a pair of sheave blocks one of which has more than two sheaves the lead line should come off one of the centre sheaves of the upper block to prevent toppling of the upper block and possible damage to the rope. Always start reeving from the becket and avoid chaffing the rope on the side plates, when you have completed reeving, the bottom block must be at right angles to the top block as in Fig. 1. The upper block has a greater hook load due to the pull on the lead rope. The sheaves in these blocks revolve at different speeds; those nearest the lead line rotate at the highest speed therefore wear out faster. For applications, which require heavy lifting or high-speed operation, bronze bushes or roller bearings should be specified when ordering. LOADS ON SHEAVE BLOCKS ANGLE Deg. FACTOR A single sheave block used to change load line direction can be 0 2.00 subjected to total loads greatly different from the weight being lifted or 10 1.99 pulled. The total load value varies with the angle of wrap between the 20 1.97 incoming and departing lines to the block. 30 1.93 In the following chart multiply the factor by the line pull to obtain the total 40 1.87 load on the block as in Fig. 2. 45 1.84 50 1.81 60 1.73 E.g. Total Load = Line Pull x Factor Fig. 2 70 1.64 80 1.53 90 1.41 100 1.29 110 1.15 120 1.00 130 .84 140 .68 150 .52 160 .30 170 .17 180 .00 All specifications & dimensions are subject to change without notice. 2 Ph: +(613) 9357 0277 www.superlift.com.au Fax: +(613) 9357 0621