Custom Search

Pulleys

Pulley basics

Sponsored Links

Pulley is a device that can increase the magnitude of the effort force. 

Without Pulley

pulley force - no pulley

With no pulley - the effort force is similar to the load - in opposite direction.

S = F         (1)

where

S = effort force (N)

F = load (N)

Single Pulley

Fixed Pulley

pulley force - single fixed pulley

With a single fixed pulley the effort force is similar (or more due to efficiency) to the load.

S = F         (2)

The advantage with the single fixed pulley is that the direction of force is changed - it is possible to pull down instead of lifting up.

Movable Pulley

pulley force - single movable pulley

 

With a single moveable pulley the effort force is half (or more due to efficiency) of the load.

S = 1/2 F         (3)

Combined Pulley

pulley force - combined pulley

With a combined moveable pulley as above - the effort force is half (or more due to efficiency) of the load.

S = 1/2 F         (4)

pulley force - combined pulley

With two pulleys and the ropes as above -  the effort force is 1/3 (or more due to efficiency) of the load.

S = 1/3 F         (5)

Sponsored Links

Related Topics

  • Dynamics - Dynamics Motion - velocity and acceleration
  • Mechanics - Kinematics, forces, vectors, motion, momentum, energy and the dynamics of objects

Sponsored Links

Related Documents

Engineering News

Engineering Standards