Calculating Weight Pull for a Pulley System

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SUMMARY

The discussion focuses on calculating the necessary pulling force for a pulley system designed to lift a 230 lb weight. The system includes a 2 1/8 inch diameter pulley and multiple 3 inch diameter sheave blocks arranged at various angles. The user seeks to determine the required winch capacity to lift the weight, considering the use of a 1/8 inch steel cable rated for 1800 lbs. The key takeaway is that the pulling force must be calculated based on the angles and configuration of the sheaves, emphasizing the importance of drawing a diagram to visualize the forces involved.

PREREQUISITES
  • Understanding of basic physics principles related to force and tension
  • Knowledge of pulley systems and mechanical advantage
  • Familiarity with cable specifications and load ratings
  • Ability to create and interpret diagrams of mechanical systems
NEXT STEPS
  • Calculate the mechanical advantage of the pulley system using the angles and diameters of the pulleys
  • Learn about the effects of friction in pulley systems and how it impacts load calculations
  • Research the principles of static and dynamic load calculations for lifting systems
  • Explore software tools for simulating pulley systems and calculating forces
USEFUL FOR

Engineers, mechanics, and hobbyists involved in designing or analyzing lifting systems, particularly those utilizing pulleys and cables.

warrior chief
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i have a 230lb weight i need to lift 12feet in the air. i have a 2 1/8 inch dia. pulley directly above it, and then 17 feet horizonally i have a 3 inch dia. sheave block. Than i drop straight down 25 feet to another 3 inch dia. sheave block which is turned at a 30 degree angle to the sheave block above, but is still in line with the sheave block above. i then go down at a 110 degree angle for 8 inches to a 3 inch sheave block on a swivel hook, so i can line up with another 2 1/8 inch dia. pulley and onto a winch. what must my winch be able to pull to lift this 230 lbs. i am using a 1/8 inch steel cable rated at 1800 lbs break. Thanks ; Warrior Chief
 
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There is a fundamental principle that all a theoretical rope/wire/string can do is pull in a direction colinear with the rope/string/wire.

So draw a diagram. Start at the weight and label the force the cable must supply. Then follow the cable, being careful what happens to the cable at each sheave. Come back and show your work.
 
Post a diagram of your setup...it sounds a bit confusing.
 

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