28-12-2012, 11:58 AM
A Project Report On DESIGN OF HYDRAULIC JACK & ANALYSIS
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ABSTRACT:
Now a day, infrastructure development is very fast growing, for that the use of R.C.C construction machinery is very widely used, but in any R.C.C construction machinery proper Mixing of raw material for Concrete is major problem. Proper mixing of raw material is important task in any construction, for that we are use latest equipments which are mechanically and hydraulically combined operated mostly. DESIGN OF OPEN HYDRAULIC JACK & ANALYSES is one of them which are operated by two prime movers one prime mover is use for hydraulic system operation for operating the hoper and other for operating drum for proper mixing of concretThe work presented herein is mainly divided into the three chapters. The first chapter introduces the concrete benching mixing machine with problem formulation and provides motivation for the project. The second chapter presents the current state of mixing machine research as presented in the form of scientific literature review.
PROJECT DEFINATION:
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 point .
Introduction
Defination Of Hydraulic Jack:-
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.
Introduction:-
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.
Pascal’s law :-
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.
-History:-
The Origin Of Hydraulic Jacks Can Be Dated Several Years Ago When Richard Dudgeon, The Owner And Inventor Of Hydraulic Jacks, Started A Machine Shop. In The Year 1851, He Was Granted A Patent For His Hydraulic Jack. In The Year 1855, He Literally Amazed Onlookers In New York When He Drove From His Abode To His Place Of Work In A Steam Carriage. It Produced A Very Weird Noise That Disturbed The Horses And So Its Usage Was Limited To A Single Street. Richard Made A Claim That His Invention Had The Power To Carry Near About 10 People On A Single Barrel Of Anthracite Coal At A Speed Of 14 M.P.H. Dudgeon Deserves A Special Credit For His Innumerable Inventions Including The Roller Boiler Tube Expanders, Filter Press Jacks, Pulling Jacks, Heavy Plate Hydraulic Hole Punches And Various Kinds Of Lifting Jacks.
Features:-
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.
Hydraulic jack:-
Hydraulic jacks are typically used for shop work, rather than as an emergency jack to be carried with the vehicle. Use of jacks not designed for a specific vehicle requires more than the usual care in selecting ground conditions, the jacking point on the vehicle, and to ensure stability when the jack is extended. Hydraulic jacks are often used to lift elevators in low and medium rise buildings.
A hydraulic jack uses a fluid, which is incompressible, that is forced into a cylinder by a pump plunger. Oil is used since it is self lubricating and stable. When the plunger pulls back, it draws oil out of the reservoir through a suction check valve into the pump chamber. When the plunger moves forward, it pushes the oil through a discharge check valve into the cylinder. The suction valve ball is within the chamber and opens with each draw of the plunger. The discharge valve ball is outside the chamber and opens when the oil is pushed into the cylinder. At this point the suction ball within the chamber is forced shut and oil pressure builds in the cylinder.
In a bottle jack the piston is vertical and directly supports a bearing pad that contacts the object being lifted. With a single action piston the lift is somewhat less than twice the collapsed height of the jack, making it suitable only for vehicles with a relatively high clearance. For lifting structures such as houses the hydraulic interconnection of multiple vertical jacks through valves enables the even distribution of forces while enabling close control of the lift.
In a floor jack (aka 'trolley jack') a horizontal piston pushes on the short end of a bellcrank with the long arm providing the vertical motion to a lifting pad, kept horizontal with a horizontal linkage. Floor jacks usually include castors and wheels, allowing compensation for the arc taken by the lifting pad. This mechanism provide a low profile when collapsed, for easy maneuvering underneath the vehicle, while allowing considerable extension.
Pneumatic jack:-
A pneumatic jack is a hydraulic jack that is actuated by compressed air - for example, air from a compressor instead of human work. This eliminates the need for the user to actuate the hydraulic mechanism, saving effort and potentially increasing speed. Sometimes, such jacks are also able to be operated by the normal hydraulic actuation method, thereby retaining functionality, even if a source of compressed air is not available.
Strand jack:-
A strand jack is a specialized hydraulic jack that grips steel cables often used in concert, strand jacks can lift hundreds of tons and are used in engineering and construction.
Working Principal:-
The hydraulic jack is a device used for lifting heavy loads by the application of much smaller force. It is based on Pascal’s law, which states that intensity of pressure is transmitted equally in all directions through a mass of fluid at rest.
The working principle of a hydraulic jack may be explained with the help of Fig. Consider a ram and plunger, operating in two cylinders of different diameters, which are interconnected at the bottom, through a chamber, which is filled with some liquid.
Working Of Hydraulic Jack:-
Hydraulic jacks and many other technological advancements such as automobile brakes and dental chairs work on the basis of Pascal's Principle, named for Blaise Pascal, who lived in the seventeenth century. Basically, the principle states that the pressure in a closed container is the same at all points. Pressure is described mathematically by a Force divided by Area. Therefore if you have two cylinders connected together, a small one and a large one, and apply a small Force to the small cylinder, this would result in a given pressure. By Pascal's Principle, this pressure would be the same in the larger cylinder, but since the larger cylinder has more area, the force emitted by the second cylinder would be greater. This is represented by rearranging the pressure formula P = F/A, to F = PA. The pressure stayed the same in the second cylinder, but Area was increased, resulting in a larger Force. The greater the differences in the areas of the cylinders, the greater the potential force output of the big cylinder. A hydraulic jack is simply two cylinders connected as described above.
An enclosed fluid under pressure exerts that pressure throughout its volume and against any surface containing it. That's called 'Pascal's Principle', and allows a hydraulic lift to generate large amounts of force from the application of a small
Assume a small piston (one square inch area) applies a weight of 1 lbs. to a confined hydraulic fluid. That provides a pressure of 1 lbs. per square inch throughout the fluid. If another larger piston with an area of 10 square inches is in contact with the fluid, that piston will feel a force of 1 lbs/square inch x 10 square inches = 10 lbs