What let you raise your car by applying a small force on it? Yeah! It is a jack, that can be carried in your car for performing basic mechanical operations. But, other than this portable type jack, a wide variety of jacks are available in the market. Jacks can be categorized based on force generation mechanisms. We have mechanical, electrical, hydraulic, and pneumatic type jacks. All these categories of jacks will lift heavy loads, but their application fields, lifting capacity, and design will vary. 

Here we can discuss more details related to hydraulic jacks.

A hydraulic jack is a mechanical arrangement that uses the power of fluids for operation. With a hydraulic jack, one can easily lift heavy loads using a small applied force. Normally, this lifting device uses a hydraulic cylinder for applying initial power. Hydraulic jacks have a wide range of applications in railways, defense, earthmoving equipments, aeronautical, material handling equipment, hydropower plants, mining and lifting platforms. The even and stable transmission movement under varying or maximum load made hydraulic jacks suitable for all the above applications. Also, jacks using hydraulics can provide increased lifting capacity over a greater distance.

When we consider the history, the patent for the portable hydraulic press was granted to Richard Dudgeon in 1851. Before this, a British patent for hydraulic jack was filed by William Joseph Curtis in 1838.

Reservoir or buffer tank, hydraulic cylinders, pump, check valve, and release valve are the important parts of hydraulic jack that assist in heavy lifting. Like every hydraulic system, the reservoir will store hydraulic fluid and with the help of a hydraulic pump, pressurized fluid will be feed to the attached cylinder. The check valve located in between the cylinder and pump will direct the flow. When the fluid enters the cylinder, the piston extends and pressurizes the second hydraulic cylinder. The release valve is used for retracting the hydraulic piston when the work is completed. The capacity of the reservoir or buffer tank will depend on the hydraulic fluid requirement for cylinder extension and retraction. More details on the hydraulic jack working are mentioned below.

How do hydraulic jack works?Hydraulic Jack Working is based on Pascal’s principle. That is, the pressure applied to a fluid stored in a container will be distributed equally in all directions. The important components of a hydraulic jack are cylinders, a pumping system, and hydraulic fluid(oil is used commonly). The hydraulic jack fluid is selected by considering certain fluid properties like viscosity, thermal stability, filterability, hydrolytic stability, and more. If a compatible hydraulic fluid is selected, it will offer maximum performance, self-lubrication, and smooth operation. The hydraulic jack design that will contain two cylinders(one small and another big) connected to each other using pipings. Both cylinders are filled partially using hydraulic fluids. While applying a small pressure on the smaller cylinder, the pressure will be transmitted equally to the larger cylinder through the incompressible fluid. Now, the larger cylinder will experience a force multiplication effect. The force exerted on all points of both cylinders will be the same. But, the force produced by the larger cylinder will be higher and it is directly proportional to the surface area. Other than cylinders, a hydraulic jack will contain a pumping system to push fluid into a cylinder through a one-way valve. This valve will restrict the backflow of hydraulic fluid from the cylinder.

Bottle jacks and floor jacks are the two types of hydraulic jacks. Hydraulic jacks with a cylindrical body and neck, that resembles a bottle is commonly known as bottle jacks or whiskey jacks. The bearing pad supported by the vertical shaft is responsible for balancing the weight of lifting object. Bottle jacks are used for repair of automobiles and house foundations, and for short verticle lifts. Floor jacks can provide a bigger range of vertical lifts. So, these jacks are commonly used by the mining industry. Unlike from the bottle jack, the horizontal shaft pushes on the crank connected to a lifting pad, which is then lifted vertically.

We can conclude this after discussing some hydraulic jack troubleshooting tips. What will you do if the hydraulic jack fails to lift an object? Low oil level can be a reason for this failure. So, at first, you need to check the oil level. If you found inadequate oil in the system, refill it. Leakage or seal failure can be another reason for this. If the seal is damaged, you need to replace the seals on the compression cylinder.