A hydraulic jack is a device used to lift heavy loads. The device itself is light, compact and portable, but is capable of exerting great force. The device pushes liquid against a piston; pressure is built in the jack's container. The jack is based on Pascal's law that the pressure of a liquid in a container is the same at all points.

A hydraulic jack is a jack that uses a liquid to push against a piston. This is based on Pascal’s Principle. The principle states that pressure in a closed container is the same at all points. If there are two cylinders connected, applying force to the smaller cylinder will result in the same amount of pressure in the larger cylinder. However, since the larger cylinder has more area, the resulting force will be greater. In other words, an increase in area leads to an increase in force. The greater the difference in size between the two cylinders, the greater the increase in the force will be. A hydraulic jack operates based on this two cylinder system.

INTRODUCTION

Pressure on a confined fluid is transmitted undiminished and acts with equal force on equal areas and at 90 degrees to the container wall.

A fluid, such as oil, is displaced when either piston is pushed inward. The small piston, for a given distance of movement, displaces a smaller amount of volume than the large piston, which is proportional to the ratio of areas of the heads of the pistons. Therefore, the small piston must be moved a large distance to get the large piston to move significantly. The distance the large piston will move is the distance that the small piston is moved divided by the ratio of the areas of the heads of the pistons. This is how energy, in the form of work in this case, is conserved and the Law of Conservation of Energy is satisfied. Work is force times distance, and since the force is increased on the larger piston, the distance the force is applied over must be decreased.

PASCAL'S LAW

The jack uses compressible fluid, which is forced into a cylinder by a plunger. Oil is usually used for the liquid because it is self-lubricating and has stability compared with other liquids. When the plunger comes up, it pulls the liquid through a check valve suction pump. When the plunger is lowered again, it sends liquid through another valve into a cylinder. A ball used for suction in the cylinder shuts the cylinder and pressure builds up in the cylinder. The suction valve present in the jack opens at each draw of the plunger. The discharge valve, which is outside the jack, opens when oil is pushed into the cylinder. The pressure of the liquid enables the device to lift heavy loads.

FEATURES OF JACK

A scissors mechanism uses linked, folding supports in a criss-cross 'X' pattern known as a pantograph.

Extension is achieved by applying pressure to the outside of a set of supports located at one end of the mechanism, elongating the crossing pattern. This can be achieved through hydraulic,  pneumatic, mechanical or simply muscular means.

It may require no power to return to its original position, but simply a release of the original pressure.

SCISSOR MECHANISM

Stroke: this is the range of height safely attained by use of a scissor lift. This is directly correlated with the number of scissor intersections and the length of the components used in the pantograph.

Size: this is the dimensions of the work platform elevated by the lift. Many lifts feature an extendable platform to increase the area's square volume.

Capacity: the maximum burden that the lift is designed to safely support, be it personnel or freight.

Tilt: in cargo-lifting situations it may be helpful to have a lift table that can pitch its load to an angle to make the load more accessible.

Specifications

TO MAKE A WORKING PROJECT ON HYDROLIC JACK.

PROCEDURE ARE AS FOLLOW---

AIM