Cable Pulling Principles (cont'd)
Calculating the Hook Load (cont'd)
Two Attachment Points
To calculate the hook loads exerted at two attachment
points, use the Reference Table and Formulas 1, 2 and 3.
Sheave with Two Attachment Points
R1
T
Formula 2:
R
R
= ________________________
1
COS A + SIN A / TAN B
R
= resultant force on left hook, anchoring and support structure
1
R
= resultant force on right hook, anchoring and support structure
2
A = angle between the left mounting and the centerline of the two legs of the rope
B = angle between the right mounting and the centerline of the two legs of the rope
R = the resultant force, or hook load; this force is exerted on the hook, anchoring and structural support
θ = the angle of change in rope direction
T = the tension exerted on the rope by the cable puller
Notes: The total load on the left support structure = R
The total load on the right support structure = R
Greenlee / A Textron Company
Ultra Tugger
R2
1
θ
2
T
θ
®
Cable Puller and Pulling Packages
R1
T
Formula 3:
R
R
= ________________________
2
COS B + SIN B / TAN A
+ the weight of the sheave.
1
+ the weight of the sheave.
2
21
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R2
1
θ
2
T
θ