The tensioning system shown is one of three being used to plumb and support a flare stack. The other two tensioning systems are not shown for clarity.
How many parts of hoist line are there in the tensioning system shown below?
Two or Three?
Extra credit: If T = 3,000 lb,
what is: R1______________
what is: R2______________
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Answer:
There are three (3) parts of hoist line for the tensioning system shown.
R1 = 2,000 lbs
R2 = 1,000 lbs.
In order to solve for the number of parts of hoist line in a pulley system, the traveling load block must first be identified. Then an imaginary cut is made just above the traveling block. The "cut" hoist lines that are supporting the traveling load block are counted. The number of "cut" hoist lines is the number of parts of line.
In this case the traveling block is the top block, because as the winch is tightened up, the top block moves or travels toward the bottom or stationary block. If the winch is let out, the top block moves away from the stationary block. The traveling block in this example is similar to the load block on a crane, except that the imaginary cut here is made below the traveling block instead of above it.
The stationary block here is similar to the point sheave on a crane.
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