Hydraulic Jacks – How They Work?

A jack is an appliance that makes use of force to elevate heavy loads. The basic mechanism of applying force varies according to the particular type of jack; however, usually it is a hydraulic cylinder or screw thread. Jacks can be classified as per the type of force they apply, i.e. hydraulic or mechanical. Hydraulic jacks are usually stronger and are able to lift heavier loads to greater heights, and include floor jacks ad bottle jacks. Mechanical jacks like house jacks and car jacks elevate heavy load and are rated according to capacity of lifting (for instance, the number of tons they are able to lift).

Working of Hydraulic Jacks

Hydraulic jacking system is dependent on force created by pressure. Importantly if a couple of cylinders (a small and a large one) are joined and force is employed to one of them, equal amount of pressure is created in both cylinders. But, as one cylinder has a bigger area, the force the bigger cylinder generates is higher, albeit the pressure in two both the cylinders will be the same. This basic principle is behind the hydraulic jacks to elevate heavy loads. They make use of pump plungers to pass oil through the two cylinders. First the plunger is drawn back, because of which the suction valve ball opens and oil is drawn within the pump chamber. When the plunger is pushed forward, oil inside the pump chamber passes in the cylinder chamber through an external discharge check valve, and the suction valve closes, which leads to building pressure inside the cylinder.

Types of Hydraulic Jacks

Floor jacks and bottle jacks are two common types of hydraulic jacks.

Floor Jacks: The floor jack shaft is horizontal, so it pushes on a crank which is attached to a lifting pad, which is elevated horizontally. Typically floor jacks give a higher range of vertical lift than bottle jacks and come in two sizes. The original jack is a foot wide, around four feet long and weighs about 200 pounds, and they can elevate 4 to 10 tons. A more compact version was later created, which is around 3 feet long and can elevate 11/2 tons. Though “mini jacks” are created, they are not approved as a standard floor jack.

Bottle Jacks: They were popular in the early 1900s when the automobile industry was taking off. They are also known as hand jacks, and offered an easy way to elevate a vehicle for servicing or roadside inspection.

Espana Gomez is an author of this blog. Recently she works as an interior design assistant in her town. She loves daydreaming about beautiful homes and interior decor.