How Does a Hydraulic Jack Work​? A Simple Guide for Beginners

We, at Coastal Hydraulics, spend each day working with machines that are carefully inspected and repaired. In the course of our activities, we regularly face cases where massive pieces of equipment are lifted easily with minimum efforts from operators. Usually, a hydraulic jack serves as a machine that performs such wonders. Perhaps, you have access to one of these tools. 

Alternatively, you may already be familiar with mechanics’ work and see them lifting cars with their hydraulic jacks. Nonetheless, most people lack information about the processes taking place inside the equipment, including topics such as hydraulic component design in Houston.

Knowing how equipment works helps you appreciate the ingenuity of its creators. Besides, you become a safer user and owner because you would be able to recognize the signals showing that something goes wrong and the system needs repairs. As our clients frequently say, a bit of knowledge about the operation of your lifting gear can help you prolong its service life greatly.

How a Hydraulic Jack Works

The secret to the amazing performance of hydraulic jacks lies in the field of fluid dynamics. With the help of a sealed system of fluids, valves, and cylinders, a hydraulic jack converts your physical effort into a mechanical one. Today, we are going to explain to you step by step…how does a hydraulic jack work?

The Physics: Understanding Pascal’s Law 

Before learning how a hydraulic jack lifts heavy loads, one needs to learn a certain law in physics known as Pascal’s principle. In fact, a hydraulic jack was created relying on that principle. A famous French mathematician Blaise Pascal discovered that if one exerts some pressure on a liquid in a sealed chamber, then this pressure will evenly distribute across all directions due to impossibility to compress liquids.

As we work with such equipment daily, we can assure you that this principle applies in all cases of using a hydraulic jack. To begin with, you should understand that a hydraulic jack consists of two different sized cylinders – a pump plunger and a lifting ram. When you exert some physical effort on the smaller cylinder, it creates pressure. In accordance with Pascal’s principle, this pressure gets distributed through the liquid inside the chambers.

Thanks to this, pressure becomes multiplied because of the difference between the surfaces. So, although you push the plunger with, say, five pounds of force, the pressure becomes distributed throughout the wider surface area of the larger cylinder. Thus, you get several thousand pounds of upward pressure, which lifts heavy loads easily.

Mechanical Processes Behind Lifting a Heavy Cargo

Step 1: Priming the System

The first thing needed for a successful operation is pumping up the hydraulic jack. To prime the hydraulic jack, you must lift its handle up and thereby make the smaller plunger pump hydraulic fluid from the storage chamber. After that, a suction valve opens and lets hydraulic fluid enter the cylinder. Immediately after, this valve closes to prevent fluid from returning to the storage chamber.

Step 2: Moving the Jack Up

Once you push the handle of a jack downwards, you exert force upon the smaller plunger and push it into a smaller cylinder. As mentioned above, once you push it upwards, the discharge valve closes and prevents any further movement. If you have ever wondered how do hydraulic jacks work, the answer becomes clear at this stage. As a result, hydraulic fluid gets pushed into the larger cylinder where a lifting ram stays. Consequently, it starts lifting a load gradually.

Step 3: Lowering the Jack

To move a heavy load, one needs to slowly open a release valve to let hydraulic fluid out of the lifting chamber gradually. A heavy load presses on a main lifting ram. As a result, it forces the fluid to move to the storage chamber through the opened valve. As you may see, a heavy load is lowered in a smooth manner and is not dropped abruptly.

FAQs

What Fluid Does A Hydraulic Jack Need To Function Properly?

Hydraulics requires special hydraulic oil to work properly. Unlike motor oil or other substitutes, it can withstand great pressure and lubricate the internal parts effectively. Do not think about filling hydraulic oil with anything else but specially designed fluid. Otherwise, seals will deteriorate, and the jack won’t perform well, which can affect how a hydraulic jack works.

Can Hydraulic Jacks Lose Lifting Power?

Unfortunately, the equipment can deteriorate and lose lifting power over time. We often see leaks that are caused by deterioration of seals. Sometimes, a jack gets clogged with air, which leads to loss of lifting capacity.

Is It Okay To Be Underneath A Load Held Up By A Jack?

No, one shouldn’t stay under such a weight as it may suddenly drop due to some internal problems. Even if it works perfectly fine at the current moment, you never know whether something goes wrong. Always use solid jack stands to prevent accidents.

Professional Servicing for Optimal Functioning

Learning the mechanism of functioning allows you to control the situation, but this does not mean that you will not have to repair your tools someday. If you notice that your tools lose power, stop working, or behave erratically, bring them to us and our specialists at Coastal Hydraulics will fix all the issues quickly. Contact us today for expert help with getting a hydraulic jack working efficiently!