Different Types of Hydraulic Jacks and How They Work

What is a hydraulic jack?

Jacks are identified by the mechanism by which force is applied to lift heavy objects. You’ve probably seen mechanical jacks such as scissor jacks that expand and contract somewhat like an accordion, or old-school ratchet jacks that use a pawl and ratchet mechanism, with the lift arm ratcheting its way up a vertical, toothed rack bar.

A hydraulic jack is a mechanical device used to lift heavy objects by applying force to a small area. The force is applied through a fluid, which is usually some type of oil. The fluid is contained in a cylinder.

How do hydraulic jacks work?

While there are several types of hydraulic jacks for sale, all hydraulic jacks are tools that use fluid mechanics to lift heavy objects. They function based on a concept known as Pascal’s Principle. This principle states that when pressure is applied to a fluid in a confined space, the pressure is transmitted evenly throughout the fluid. In a hydraulic jack, an incompressible fluid links two cylinders (a large cylinder and a small cylinder) so that when a given amount of pressure is applied to one cylinder, that same pressure is transferred to the second cylinder.

Due to the fact that pressure is equal to force per unit area, a cylinder with a larger area will experience a multiplicative force. While the pressure on both cylinders is the same, the force produced on the larger cylinder, or piston, based on its area, will be greater. This is why hydraulic jacks can be used to lift extremely heavy objects. The pressure generated by the fluid in the jack is transferred to the object being lifted, allowing it to be raised with relative ease.

What are the different types of hydraulic jacks?

Hydraulic jacks come in many different shapes and sizes, each designed for a specific purpose. The most common types are bottle jacks, toe jacks, trolley jacks, and heavy equipment jacks.

Bottle Jacks

Bottle jacks, which can usually be found in your vehicle, are used when you need to replace your flat tire or change out one of your fluids. These tools provide enough clearance to easily change a tire or make adjustments. Make sure that there is one of these simple jacks in your car before hitting the road. With this type of jack, because the clearance is limited, it is typically only used for car maintenance or tasks with similar size objects. You simply place the jack underneath the object you need lifting and raise it until you reach the desired height.

Toe Jacks

The toe jack (often called a floor jack) is also used for lifting heavy loads. Toe jacks are often shaped like a typical bottle jack, except that instead of placing the cylinder under the car or object to be lifted, a 90-degree toe attached to the cylinder is placed under the object. A toe jack is ideal for situations where there is little clearance between the floor and the object to be lifted.

Trolley Jacks

Another type of hydraulic jack that comes in handy when there is limited ground clearance is the versatile trolley jack. As the name suggests, trolley jacks are mounted to casters that allow the jack to be rolled into place underneath the car or other load to be lifted.

Heavy Equipment Jacks

A simple bottle or toe jack, as mentioned previously, isn't going to work when you need to lift a heavy piece of equipment for servicing. These large and heavy pieces of equipment need loading capacities beyond the capabilities of other jacks. The jack you use needs to be solidly constructed, forged and made from materials of the highest quality. Failing to do so could lead to danger to you as well as others around you.

Where are hydraulic jacks used?

Hydraulic jacks are used in a variety of industries and applications. For example, they are commonly used in automotive and construction contexts. In the automotive industry, hydraulic jacks are used to lift vehicles so that mechanics can have access to the underside of the car. The simplest of these is the earlier mentioned bottle jack that likely came with your car.

In manufacturing and heavy industry is typically where you’ll find the heavy equipment jacks used. Sometimes they’re used to facilitate repair of large machines, and other times, they’re an integral part of the machines.

In construction, hydraulic jacks are used to lift heavy loads and materials. Hydraulic jacks can be used for purposes such as lifting a house so that its foundation can be repaired.

Conclusion

Although they all use the same principle of physics, hydraulic jacks come in a variety of shapes and sizes, each with its own unique application. The most common type of hydraulic jack is the simple bottle jack, which is used to lift vehicles. By understanding the intended purpose of each jack, you can choose the right one for your needs.