Hydraulic Jacks: Structure and Operating Principle

Hydraulic jacks are powerful tools widely used in various fields, from lifting cars in garages to raising heavy components in construction. So, what is a hydraulic jack? How does it work to lift such heavy objects?

What is a Hydraulic Jack?

A hydraulic jack, also known as a hydraulic bottle jack, is a mechanical device that uses liquid (usually oil) to generate lifting force. The device can lift and lower objects with a load capacity ranging from dozens to hundreds of tons.

Each type of jack has different structures and principles to meet specific work requirements. For example, with a mini crane, the hydraulic jack not only generates lifting force but also helps control the movement of the crane arm.

Detailed Component Structure of a Hydraulic Jack

A hydraulic jack is a powerful tool used in many fields. Basically, a hydraulic jack consists of 5 main parts: the fluid reservoir, control valve, cylinder, lock, and hydraulic system. Each part plays a vital role in the operation of the jack:

• The fluid reservoir, also called the solvent tank or hydraulic tank, is where the liquid—a key factor in force transmission—is stored. Simultaneously, the hydraulic oil transmits force to the cylinder, creating thrust to lift heavy objects.
• The control valve coordinates the flow of liquid to the two cylinders. Users can easily control the jack to lift or lower.

• The lock plays an important role in ensuring user safety. The lock helps fix the lifting height and prevents the risk of the jack dropping suddenly during operation.
• The cylinder is the primary load-bearing part of the hydraulic jack. In this system, one cylinder receives the initial impact force, while the other amplifies it to raise the jack and create powerful lifting force.
• The power generation system receives input force from a hand pump or electric hydraulic pump. Its mission is to convert the impact force into fluid pressure to generate the necessary lift.

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Operating Principle of a Hydraulic Jack

The operating principle of a hydraulic jack is based on Pascal’s Law. This principle states that pressure applied to an incompressible fluid is transmitted equally in all directions throughout the fluid and the container.

Specifically, the hydraulic jack operates according to the following mechanism:

Lifting Phase

To lift a heavy object, the valve is first opened to connect the two cylinders. Then, a force F1 is applied to the cylinder with surface area S1. This force F1 is transmitted through the liquid and acts on the cylinder with surface area S2 (S2 > S1), creating a force F2 larger than F1. This force F2 pushes the cylinder up by a distance L2, thereby lifting the heavy object. To maintain the lifting height, the user simply needs to close the valve.

Lowering Phase

To lower the heavy object, the valve lock is opened. At this point, the valve allows the oil to flow back into the reservoir. Consequently, the cylinder with surface area S2 lowers, bringing the heavy object down with it.

Classification of Hydraulic Jacks

Hydraulic jacks are very diverse in type, each designed to suit different purposes. Here are some common types:

Classification by Thrust Capacity

This is a common classification based on the maximum lifting capacity of the jack. Manufacturers design and produce various jacks with different thrust capacities. Load capacities range from 2 tons, 5 tons, 10 tons, 20 tons, 30 tons… up to 200 tons or more. Users can easily choose the hydraulic jack that fits their needs.

Classification by Lifting Direction

Based on the ability to lift in one or two directions, hydraulic jacks can be divided into two types:

Single-Acting Hydraulic Jack

This type of jack has a simple design, typically used for lifting and lowering objects vertically. This type of jack has a smaller maximum load capacity compared to double-acting types.

Double-Acting Hydraulic Jack

This type allows objects to be lifted and lowered both horizontally and vertically. Therefore, it is also known as a horizontal jack. Double-acting jacks are used for complex tasks that require flexible lifting capabilities.

Conclusion

Hydraulic jacks are powerful and versatile tools widely applied in many different fields. With a variety of types and load capacities, hydraulic bottle jacks can generate large lifting forces with minimal effort, making it easy for people to lift heavy objects. We hope the information in this article from Naltako has helped you better understand this modern equipment.