Work Load / Stress Formula / Load Calculation

Work Load / Stress Formula / Load Calculation

Block Division, Inc., has established through an accredited testing laboratory the capacity at which our products may be safely used. This may be defined as the safe working load limit, a chain or cable rope pulley block load calculation, or a force calculator.  The safe working load limit (mechanical advantage) is the maximum load in pounds which should ever be applied, and when the load is applied uniformly and in direct tension to a straight segment of wire rope.  By changing the degree of angle between lead and load angle, this also affects the stress on the block. The stress on the eye may be decreased by increasing the angle between the load and the lead angle.  See chart 1 and illustration below.

Stress Formula: (L x A = S)
Load in pounds (L) multiplied by the Angle of pull (A) equals the stress generated in lbs. on the Block (S).

Safe Work Load Limit: This is the maximum load (in lbs.) which can be applied to the Block and which has been established by Block Division, INC. (Load Capacity)

All wire rope and fittings should be thoroughly inspected before use and replaced if found defective. Any alteration to our products voids all said and implied warranties, guarantees, and liabilities.

To insure long life for both wire rope, and pulleys, or sheaves…inspect regularly. Keep wire rope lubricated and check for wire rope fraying. Corrosion of wire strands internally or externally can drastically affect the strength of wire rope. When noticeable wear appears on the sheaves or rope, replace it.