Jack (device)

A jack is a tool for lifting.

It can lift a heavy car. This helps people fix things.

Some jacks use a screw to lift. Others use oil to push things up.

Some jacks use air to lift. These can even lift an airplane. A jack can even lift a house! It is a very strong tool.

A jack is a tool used to lift heavy things.

It can help people fix cars or move buildings. Some jacks use a screw to lift.

A scissor jack uses a screw and metal parts. This lets a person lift a car by hand. Some car jacks use electricity to work automatically.

Other jacks use liquid to create power.

We call these hydraulic jacks. They use a liquid like oil. A pump pushes the oil into a cylinder. This makes the oil push up with great force.

A bottle jack looks like a bottle. It can lift up to 50 tons. These are used to fix cars or house foundations.

Some jacks use air instead of liquid.

These are called inflatable jacks. They are like strong air bags. Rescuers use them to lift heavy objects. They can even lift an airplane.

You can even stack two bags to lift higher. A farm jack is another kind. It is a steel beam used by off-road drivers.

A jack is a mechanical tool used to lift very heavy loads.

Most people know them as car jacks used to fix tires. They can also lift much bigger things like houses or even airplanes. Some jacks are small and delicate, like parts inside a musical instrument. Others are huge and can lift hundreds of tons. These tools are important because they help people do hard jobs safely.

There are different ways these tools work.

A mechanical jack uses a screw thread to move things up. A scissor jack uses a screw and metal links to lift a car.

A hydraulic jack uses a liquid, like oil, to create power. A pump pushes the oil into a cylinder to make it rise.

Some jacks even use compressed air to inflate a strong bag. This is called an inflatable jack, and it can lift an airplane.

People have been making different kinds of jacks for a long time.

In 1679, a record shows a jack used to move large pieces of timber.

Later, William Joseph Curtis filed a patent for a hydraulic jack in Britain in 1838.

In 1859, Richard Dudgeon was granted a patent for a portable hydraulic press. Another inventor, P.J. Harrah, created the versatile farm jack in 1905.

Different jacks have different strengths and uses. A hydraulic bottle jack can lift up to 50 tons. A house jack can lift a building that weighs 2.5 tons. Inflatable rescue bags use different air pressures to work. Low-pressure bags use 7.25 psi for a large lift.

Medium-pressure bags use 15 psi for their work.

High-pressure bags use between 90 and 145 psi to lift heavy loads.

You might see these tools in your daily life without knowing it.

A floor jack helps a mechanic work under a car in a garage.

If you see a house being moved, workers might be using house jacks. Even music involves jacks in a special way.

In a harpsichord, small wooden jacks lift parts to pluck the strings.

These tools show how simple ideas can move the heaviest things.

A jack is a mechanical device designed to apply great force or lift heavy loads.

These tools are essential for performing maintenance on vehicles and repairing large structures. They allow humans to move objects that would otherwise be impossible to lift by hand. While most people associate the word with car repairs, the term covers a wide range of machinery. Some jacks are massive enough for industrial construction, while others are tiny components in musical instruments.

Mechanical jacks often rely on a screw thread to generate lifting power. One common example is the scissor jack, which uses a leadscrew and a 4-bar linkage.

By turning the screw, a person can use manual force to lift a heavy vehicle. Some modern versions are even electric. These use 12-volt electricity from a car's cigarette lighter to raise and lower the jack automatically. Another mechanical type is the house jack, or screw jack. This device uses an acme-threaded rod to lift buildings from their foundations. To keep the device stable, it features a cast-iron circular pad. This pad moves independently so the post does not turn as the rod is rotated.

Hydraulic jacks operate using the principles of fluid mechanics.

These devices use a liquid, such as oil, because it is stable and self-lubricating. Since liquids are incompressible, they can transmit force effectively. The process begins when a pump plunger pulls back to draw oil from a reservoir. A suction check valve allows the oil to enter the pump chamber. When the plunger moves forward, it pushes the oil through a discharge check valve into a cylinder.

As the oil enters the cylinder, the suction valve closes and pressure builds. This pressure then forces the lifting mechanism upward.

There are several specialized forms of hydraulic jacks used for different tasks. The bottle jack, sometimes called a whiskey jack, has a cylindrical body and a neck.

It uses a vertical lifting ram that emerges from the body. These can be used for automobile repairs or to lift house foundations. Some bottle jacks can even lift up to 50 tons.

Another type is the floor jack, also known as a trolley jack. It uses a horizontal piston and a bellcrank to provide vertical motion. Because it includes wheels and casters, it is easy to maneuver under a vehicle.

For massive engineering projects, engineers use strand jacks. These specialized hydraulic devices are designed to grip and lift heavy steel cables.

Other lifting technologies use compressed air instead of liquid. An inflatable jack, or pneumatic lifting bag, is an air bag that inflates to lift objects.

These are used to lift everything from automobiles to large airplanes. Rescuers specifically use these bags to lift heavy objects off of people. There are three main pressure levels for these rescue bags. Low-pressure bags operate at 7.25 psi to provide a high vertical lift. Medium-pressure bags operate at 15 psi. High-pressure bags operate between 90 and 145 psi to provide much higher lifting capacities.

You can even stack two bags together to increase the lift height.

The history of the jack shows how technology has evolved to save human labor. The word "jack" was used in the 16th century to describe a man of low status. Later, it was applied to machines that took the place of men or saved their effort. The first recorded use of "jack" to mean a lifting machine was in 1679. This record described an engine used to move great pieces of timber. In 1838, William Joseph Curtis filed a patent for a hydraulic jack in Britain. Later, in 1859, Richard Dudgeon patented the portable hydraulic press.

In 1905, P.J. Harrah invented the versatile farm jack.

This tool is popular with off-road drivers because it can lift, winch, clamp, and pull.

Safety is a critical part of using these powerful tools. Because jacks handle extreme weights, they must be used with great care. Users must consider ground conditions and the specific jacking point on a vehicle to ensure stability. Organizations like the American Society of Mechanical Engineers (ASME) have developed safety standards. In the United States, the ASME creates standards for portable automotive service equipment. These standards cover many types of jacks, including hydraulic hand jacks and emergency tire-changing jacks. Following these rules helps ensure that lifting heavy loads remains a controlled and safe process.