What Is a Hydraulic Jack – Essence and Types

In many fields, it is necessary to lift and hold loads at a certain height. Often, the weight of these loads exceeds human capacity, which is where hydraulic jacks come into play.

WHAT ARE HYDRAULIC JACKS AND HOW DO THEY WORK?

A hydraulic jack is a type of lifting device with a simplified design. It generally consists of two cylinders filled with hydraulic fluid, a connecting pipe, lifting levers (pistons), and a pump.

The hydraulic jack operates based on the principle of fluid mechanics, known as the “Pascal’s Principle.” In other words, the device works by creating pressure that moves the hydraulic fluid (oil) through the two cylinders via the pump piston.

When the piston is pulled back, the intake valve opens and draws oil into the pump chamber. When pushed forward, the oil is transported through the discharge valve into the cylinder chamber.

The intake valve then closes, leading to a build-up of pressure in the chamber, which in turn causes the piston in the chamber to rise and lift the heavy load or vehicle to a specified height.

Types of Hydraulic Jacks

Hydraulic lifts vary both in design and type of drive, as well as in load capacity.

“Bottle” Type

They are called this way because their cylinders resemble the design of milk bottles. This type of hydraulic jack became popular in the 1900s when the automotive industry began to develop. Also known as manual jacks, they provide convenient access for mechanics performing inspections or repairs on vehicles.

Their distinguishing feature is that they have a vertical telescopic rod that directly bears the weight of the object when lifted.

These jacks are widely used in automotive service centers and by vehicle drivers, as they are stable, easy to use, and have a load capacity ranging from 1.5 to over 20 tons.

Their ability to lift heavy loads makes them particularly preferred for repairing heavy agricultural machinery, trucks, and other types of heavy equipment.

“Trolley” or Floor Jacks

The shaft of floor jacks is horizontal and presses the lever (crank) connected to the lifting mechanism (pad), which in turn lifts the object vertically. This type of jack typically provides a greater range of vertical lift than “bottle” jacks and is available in two sizes.

In terms of load capacity, floor jacks can lift and hold loads from 4 to over 20 tons. Mini floor jacks are also available in the commercial market, used in both service centers and at home for vehicle repairs and inspections.

Jacks for Lifting Specific Loads

These types of lifts are primarily used for lifting specific machines and loads where the clearance between the floor and their base is too small to use a floor jack or “bottle.”

Hydraulic Jacks for Leveling and Stabilizing

This type of jack is usually compact, portable, and uses a mechanical screw mechanism to lift loads. They are most commonly used for leveling and stabilizing trailers, caravans, and similar items.

Scissor Jacks

These are compact hydraulic lifts that use a mechanical screw, the rotation of which leads to the lifting or lowering of a set of scissor arms that expand or retract depending on the position of the mechanism.

Scissor jacks can currently be found in almost every car trunk, as drivers use them to change a tire on the road if necessary.

Ratchet Jacks

These are compact jacks that use a mechanism with pawls and ratchets to lift and lower loads. Years ago, this type of lift was mainly used for changing tires on the road, but today their use is significantly limited.

WHEN ARE JACKS USED FOR REPAIRS?

As previously mentioned, lifts have a very wide application, as they can lift and hold heavy vehicles at a certain height.

Typically, in service centers, professional hydraulic jacks are used both for inspecting the suspension and tires of vehicles and for performing various repair tasks on the car. In other words, these lifting devices are extremely beneficial for mechanics.

Compact jacks are intended for non-professional use, and many amateur mechanics use them in their home workshops and garages when they need to change a tire, brake discs, car shock absorbers, and more.

Advantages of Hydraulic Jacks

They are:

• The design of all types of jacks operating on the principle of hydraulics can be selected according to needs. The market offers a variety of models that differ in design, construction, load capacity, intended use, and specific features.
• They provide extremely smooth lifting and lowering of objects. This is due to the operating principle of the lifts and the incompressible fluid they use.
• They offer high efficiency (up to 80%) and can handle loads of up to 100 tons or more with relatively little force applied to the pump piston.
• The service life of hydraulic jacks is long, the reliability of the construction is high, and the safety of operation is guaranteed.
• Lifts can be selected according to load intensity. The market offers both high-class professional jacks with an optimal number of working cycles and non-professional budget models intended for low-intensity use, guaranteed for a minimum of 104 working cycles.
• Their use is very easy. Working with a hydraulic jack requires only manual operation with the lever.

Disadvantages of Hydraulic Jacks

They are:

• There may be difficulties in adjusting the lowering height. This is explained by the fact that each model mechanism may have a different design depending on the manufacturer.
• Sometimes, certain working components may fail. To avoid this, it is necessary to monitor the oil level and check seals and valves for leaks, and if any are found, the jack must be repaired immediately.

In Conclusion

Hydraulic jacks are versatile devices that find extremely wide application in various fields of activity. Thanks to them, we can quickly and easily handle lifting and holding heavy loads.

These devices are very useful in every service, in construction, mining, medicine, and more, as well as in everyday life. They are always within reach when we need to handle a tire change or inspect the suspension of a vehicle.