A pulley is one of the original simple machines. The pulley was possibly created by Archimedes in B.C. times. Its original use was to lift buckets of water. The term sheave can also be used to refer to a pulley.
What is a Pulley?
A pulley is a simple machine consisting of a wheel rotating about its axle. It is constructed by looping a rope or a cable around the groove of the wheel. Therefore, the three main parts of a pulley are the wheel, axle, and rope. A pulley is used for lifting heavy objects by applying force at one end of the rope.
Types of Pulley
Types of Pulley is listed below:
- Fixed Pulley
- Moving Pulley
- Compound Pulley
- Block and Tackle Pulley
- Cone Pulley
- Swivel eye Pulley
- Fixed eye Pulley
Fixed Pulley
In this pulley, the wheel is fixed to a hard structure while the rope is loose. It does not allow any redirection of force. So instead of lifting an object, the object can be pulled using this pulley.
Moving Pulley
Here, the pulley’s wheel is not linked to any surface but the rope is linked to a stationary surface. A heavy load is attached to the wheel rather to the rope and when the rope is pulled, the wheel can be seen sliding up the rope along with the load. This needs less work compared to lifting the load directly.
Compound Pulley
It has both stationary and movable pulley. Here the load is kept on the wheel of the movable pulley which again is connected to the rope of a fixed pulley. Using this type of pulley, redirection of both the force applied and the total workload is possible.
Block and Tackle Pulley
It can reduce the effort required to move a heavy object. It has several movable and fixed pulleys arranged in parallel with each other in such a way that fixed ones are with fixed and movable are with the movables. An each pair is linked with another pair.
Cone Pulley
It consists of multiple pulley of decreasing circumference piled on top of each other, forming a cone shape. This arrangement allows to shift the speed of movement of pulleys. The good example of this would be multi gear bicycles.
Swivel Eye Pulley
This provides dynamic rotation in which the block holding the pulley wheel will rotate. This helps when the application requires a little rotation when picking up the load. These can be used with fibrous, nylon or wire ropes.
Fixed Eye Pulley
Here, the eye is fixed on the pulley block, it cannot be turn. This systems uses two or more pulleys and reduces the effort considerably.
Use of Pulleys
Pulleys are used singly or in combination to transmit energy and motion. Pulleys with grooved rims are called sheaves. In belt drive, pulleys are affixed to shafts at their axes, and power is transmitted between the shafts by means of endless belts running over the pulleys.
One or more independently rotating pulleys can be used to gain mechanical advantage, especially for lifting weights.
Other Applications of Pulleys:
- Pulley used for drinking water – Use to lift water from the well by making use of a pulley.
- Pulley in Flag Raising – Use to raise the flag to its pole.
- Pulleys in Elevators – Used in lifting the cars where counterweight is used to balance the weight of the car.
- Pulley in Vehicles – Pulleys is used in vehicles to increase their power and make them run more smoothly.
50+ Real-life examples of Pulley
Pulleys exist in everyday life. Often, they allow users to save time and energy.
Some examples include:
- Weightlifting machines: Machines that incorporate the use of resistance with cables depend on pulleys to change the direction of the force.
- Flag hoisting pulleys: Flag poles have a pulley at the top of the pole in order to lift the flag along the rope.
- Window blinds: The opening and closing mechanism for blinds is a pulley system.
- Construction pulleys: From cranes to fixed pulleys on the top of construction sites, these are essential in lifting heavy objects.
- Elevators: A strong electronic pulley system controls the up and down movement of elevators.
- Wells: In order to lower and raise the bucket in water wells, a pulley is used.
- Theater curtains: Multiple pulleys are used to open and close the heavy curtains in theaters.
- Zip Line: A compound pulley system is used to transport people or objects along a zip line.
- Sailboat Rigging: The rigging on a sailboat often incorporates compound pulleys to control the sails.
- Rescue Systems: Compound pulleys are used in rescue operations to lift heavy objects or individuals.
- Hanging Gardens of Babylon: Historical accounts suggest that the Hanging Gardens might have used compound pulleys for irrigation.
- Ski Lifts: Some ski lifts utilize compound pulley systems for moving skiers up the slope.
- Amusement Park Rides: Various rides use compound pulleys for lifting and lowering passengers.
- Surgical Hoists: In hospitals, compound pulleys are used for surgical hoists to lift and move patients.
- Hoist Systems in Automotive Garages: Car repair garages use compound pulleys to lift heavy engines or vehicles.
- Bungee Jumping: The bungee cord system often incorporates compound pulleys for a controlled descent.
- Conveyor Belt Systems: Some conveyor belts use compound pulleys for efficient material handling.
- Tree House Elevator: Compound pulleys can be used to create a simple elevator system for a treehouse.
- Airplane Hangar Doors: Hangar doors may use compound pulleys for easy opening and closing.
- Window Washing Systems for Skyscrapers: Some systems use compound pulleys for raising and lowering window washing equipment.
- Trapeze Acts: In circus performances, trapeze acts may use compound pulleys for aerial stunts.
- Loading Docks: Compound pulleys can assist in lifting and moving heavy cargo at loading docks.
- Gantry Crane: A gantry crane uses compound pulleys for lifting and moving heavy loads within a confined space.
- Greenhouse Ventilation: Compound pulleys may be used to control ventilation systems in greenhouses.
- Drawbridge Mechanism: Some drawbridges use compound pulleys to facilitate the raising and lowering of the bridge.
- Hay Loft Systems in Barns: Traditional barns may use compound pulleys for lifting hay bales to the loft.
- Marionette Puppet Systems: The strings of marionette puppets often incorporate compound pulleys for controlled movement.
- Circulatory System Model: Some educational models demonstrating blood flow use compound pulleys.
- Aquarium Tank Cleaning System: Compound pulleys can be used to lift and clean large aquarium tanks.
- Windlass Systems on Ships: Compound pulleys are used in windlass systems for raising anchors on ships.
- Prison Cell Doors: Historical prisons may have used compound pulleys for opening and closing cell doors.
- Automated Blinds in Smart Homes: Smart home systems may use compound pulleys for automated blind control.
- Automated Closet Rods: Some automated closet systems use compound pulleys for raising and lowering hanging rods.
- Antique Well Sweep: An antique well sweep uses compound pulleys for drawing water from wells.
- Agricultural Well Systems: Some agricultural setups use compound pulleys for well water extraction.
- Roller Coaster Systems: Some roller coasters use compound pulleys for the initial ascent.
- Firefighter Rescue Systems: Compound pulleys are used in firefighter rescue systems for lifting people from heights.
- Parachute Deployment System: The parachute deployment mechanism in some systems uses compound pulleys.
- RV Awning Systems: Some RV awnings use compound pulleys for easy extension and retraction.
- Automated Garage Storage Systems: Garage storage systems may use compound pulleys for raising and lowering stored items.
- Gym Cable Machines: Cable machines in gyms often use compound pulleys for resistance training.
- Chandelier Hoists: In large venues, chandeliers may use compound pulleys for maintenance and cleaning.
- Biomedical Research Equipment: Some laboratory equipment uses compound pulleys for controlled movements.
- Rock Climbing Systems: Some rock climbing setups use compound pulleys for assistance during ascent.
- Aqueduct Gates: Historical aqueducts may have used compound pulleys for controlling water flow.
- Car Towing Systems: Some tow truck systems use compound pulleys for lifting and towing vehicles.
- Oil Rig Systems: Compound pulleys may be used in oil rigs for lifting heavy equipment.
- Clotheslines can use pulley systems in order to make it easier to pull clothes toward the user.
- Pulleys can be used to place birdfeeders high in trees or on poles, and then to pull them down when they need to be refilled or removed.
- Roofers may use pulleys in order to hoist all of the shingles up on to the roof instead of attempting to carry them.