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Ladder

technology Maturity 11-13 Next article →

A ladder is a tool used to climb up or down.

Ladder
Ladder

Most ladders are rigid, meaning they are stiff and hold their shape. These ladders have side parts called stringers or rails. The steps you climb on are called rungs. Some ladders are self-supporting, like a step ladder. Others must lean against a wall to stay upright. Rigid ladders are often portable, but some are fixed to buildings. They can be made of wood, metal, or even tough plastic.

Ladder aluminum
Ladder aluminum

Ladders work in different ways depending on their design. A step ladder uses hinges to form an inverted V shape. It stays open using stays to keep it steady. Extension ladders are made of two or more lengths. These lengths slide together for easy storage. They can also slide apart to make the ladder longer. Some firefighters use very large extension ladders. These can be 65 feet or 20 meters long. They use special poles to help raise and steady the heavy weight.

Ladder
Ladder

Humans have used ladders for a very long time. We can find evidence of them in ancient art. A rock painting in Spain is at least 10,000 years old. It shows two people using a long, flexible ladder. They used it to reach a honeybee nest to get honey.

Volute Krater - Iliad - Geneva 1
Volute Krater - Iliad - Geneva 1

In the 1800s, people made new kinds of ladders. Henry Quackenbush patented the extension ladder in 1867. Later, in the 20th century, aluminum became popular. It is much lighter than wood, which makes it easier to carry.

There are many specific types of ladders for different jobs.

Mobile safety steps
Mobile safety steps

An orchard ladder has three legs to fit between tree branches. A swim ladder helps people get in and out of boats. Some ladders are even made of rope or wire. These are called flexible ladders. They are great for tight spaces or curved objects.

Riverbend cave
Riverbend cave

In the United States, ladders are sorted by how much weight they hold. A Type IAA ladder is extra heavy duty and holds 375 pounds. A Type III ladder is for light use and holds 200 pounds.

Safety is the most important part of using a ladder.

ladder skid mark
ladder skid mark

If a ladder is at the wrong angle, it can slip or fall. The safest angle is 75.5 degrees. You can find this angle using the 4 to 1 rule. For every four units of height, move the base one unit away from the wall.

Leaning ladder setup
Leaning ladder setup

Many ladders have rubber feet to help them grip the ground. This prevents the metal from sliding on hard surfaces. Some people also use a ladder standoff. This is a device that holds the top of the ladder away from the wall. It helps the ladder clear obstacles like roof edges.

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🖼️ Images & Media (9)
Ladder.webp
File:Volute Krater - Iliad - Geneva 1.jpg
Volute Krater - Iliad - Geneva 1.jpg
File:Ladder aluminum.jpg
Ladder aluminum.jpg
File:Mobile safety steps.jpg
Mobile safety steps.jpg
File:NY Fire escape 1.jpg
NY Fire escape 1.jpg
File:Riverbend cave.jpg
Riverbend cave.jpg
File:ladder skid mark.jpg
ladder skid mark.jpg
File:Leaning ladder setup.svg
Leaning ladder setup.svg
Occupational Ladder Fall Injuries —...
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