Figure 13-16.-Transferring wire rope from reel to drum.Figure 13-17.—Fleet angle relationship.TOP or from BOTTOM TO BOTTOM, as shown infigure 13-16.Fleet AngleThe fleet angle is formed by running wire ropebetween a sheave and a hoist drum whose axles areparallel to each other, as shown in figure 13-17. Toolarge a fleet angle can cause the wire rope to climb theflange of the sheave and can also cause the wire rope toclimb over itself on the hoist drum.Sizes of SheavesThe diameter of a sheave should never be less than20 times the diameter of the wire rope. An exception is6 x 37 wire for which a smaller sheave can be used,because this wire rope is more flexible.The chart shown in table 13-1 can be used todetermine the minimum sheave diameter for wire ropeof various diameters and construction.Reverse BendsWhenever possible, drums, sheaves, and blocksused with wire rope should be placed to avoid reverseor S-shaped bends. Reverse bends cause the individualwires or strands to shift too much and increase wear andfatigue. For a reverse bend, the drums and blocksaffecting the reversal should be of a larger diameter thanTable 13-1.–Suggested Minimum Tread Diameter of Sheaves and Drums13-8
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