CONSTRUCTION OF INDUSTRIAL WHEEL BARROW
Wheelbarrow is a simple machine, which belong to the second-class lever. This is because the load or resistance is placed between the effort and the fulcrum. It is used in many areas of work to convey loads that are too heavy or bulky to be carried by hand. Wheelbarrow can be used as farm equipment, industrial equipment among others.
However, the efficiency of the wheelbarrow depends on the materials used for the construction. A wrong choice of these materials can reduce the efficiency and the life span of the machine.
Although no machine can operated with 100 percent efficiency because the friction of its parts always use up some of the energy that is being supplied to the machine. But friction can be decreased by oiling any sliding or rotating parts.
Moreover, depending on the type/size of machine to be constructed, the materials are reduced to smaller and more convenient sizes. The shapes and forms are changed by the following constructional operations, marking out, cutting, drilling, filling, recurring, taping broaching, folding/bending, welding, surface coating etc.
Most of these operations may be carried out by use of manual or mechanized processes depending on the size of the workshop.
In conclusion, a fixed amount of load was placed on the wheelbarrow to determine the efficiency and the effort required to lift the load. And according to the result gotten, the machine is highly efficient and required a very small effort to move objects many times their own size.
TABLE OF CONTENT
Letter of transmittal
Table of contents
1.3 Principles of machines
1.5 Mechanical advantage
1.6 Simple machine
2.1 Science of material
2.2 Properties of material
2.2 Alloy designation
3.1 Material selection
3.2 Basic machine tool operation
3.3 Metal removal
3.4 Metal forming
3.5 Construction method
3.6 Autographic drawing
4.2 Cost evaluation
Archimedes, a Greek, was also a physicist and a mechanical engineer who proved the law of the lever and invented the compound pulley. With these machines, it is possible to move a great weight with a small force. Archimedes reportedly once boasted, “give me a place to stand on, and I will move the entire earth”.
He was referring to the way levers and pulleys can help people move objects many times their own size. He proved this law of pulley by using a system of pulleys to move a ship fully loaded with goods and passengers.
In his investigations of force and motion, Archimedes also discovered that every object has a center of gravity and the force acting on this point must be conquered before the body will be moved or lifted. This is because it is a single point at which the force of gravity appears to act on the object.
A machine is a device that does work. They are designed to make life easier for us. Some machines perform tasks that would be impossible to do without them. We use machines all the time, industries use them in lifting and moving very heavy loads. Without machines, the residents of our cities would find it more difficult to live, and farmers could not raise enough food to feed us.
Engineers have constructed a wide variety of machines to satify their needs. Early people made stone axes that served as weapons and tools. The machines that were gradually developed gave people great control over their environment.
PRINCIPLES OF MACHINE
A machine produces force and controls the direction and the motion of the force. But it cannot create energy. A machine can never do more work than the energy put into it. It only transforms one kind of energy, such as electrical energy, and passes it along as mechanical energy. Some machines, such as chisel engines or steam turbines, change energy directly into mechanical motion other machines, such as simple machines, simply transmit mechanical work from one part of a device to another part.
A machine’s ability to do work is measured by two factors. They include Efficiency and Mechanical Advantage.
The efficiency of a machine is the ratio between the energy it supplies and the energy put into it. No machines can operate with 100 percent efficiency because the friction of its parts always uses up some of the energy that is being supplied to the machine.
Although friction can be decreased by oiling any sliding or rotating parts, all machines produce some friction. For this reason, a perpetual motion machine is impossible.
A simple lever is a good example of a machine that has a high efficiency. The work it puts out is almost equal to the energy it receives, because the energy used up by friction is quite small. On the other, an automobile engine has an efficiency of only about 25 percent, because much of the energy supplied by the fuel is lost in the form of heat that escapes into the surrounding air.
In machines that transmit only mechanical energy, the ratio of the force exerted by the machine to the force applied to the machine is known as Mechanical Advantage. Mechanical advantage can be demonstrated with a crowbar, which is a type of lever. When one end of the crowbar is directly under the weight, a part of the crowbar must rest on a FULCRUM (support). The closer the fulcrum is to the load, the less the effort required to raise the load by pushing down on the handle of the crowbar, and the grater the mechanical advantage of the crowbar.
For example, if the load is kilograms, and the distance from the load to the fulcrum is one fourth of the distance from the handle to the fulcrum, it will take 50 kilograms of effort to raise the load. Therefore, the mechanical advantage will be four to one. But the distance to the load moved will be only one fourth of the distance through which the effort is applied.
SIX SIMPLE MACHINES
Most machines consist of a number of elements, such as gears and ball bearing, that work together in a complex way. But no matte how complex they are, all machines are based in some way on six types of simple machines. These six types of machines are the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw.
Lever is one of the six simple machines for performing work. It consist of a rod or bar that rests and turns on a support called a FULCRUM. A force of effort is applied at one end of the rod to lift a load placed at the other end. The distance between the fulcrum and the load is the LOAD ARM. The distance from the fulcrum to applied force is the EFFORT ARM.
A lever can help lift a weight with less effort. Prying something loose with a crowbar is using a lever. Some machines, such as a catapult use a lever to hurl objects.
CLASSES OF LEVERS
FIRST CLASS LEVERS
This class of levers have the fulcrum placed between the load and the effort, as in the seesaw, crowbar, and balance scale. If the two arms of the lever are of equal length, the effort must be equal to the load. To lift 10 pounds, an effort of 10 pounds must be used. If the effort arm is longer than the load arm, as in the crowbar, the effort travels further and in less than the load. A pain of scissors is a double lever of the first class.
SECOND CLASS LEVERS
These have the load between the effort and the fulcrum. A wheel barrow is a second-class lever. The axle of the wheel is the fulcrum, the handles take the effort, and the toad in placed between them. The effort travels a greater distance and is less than the load. A nutcracker is a double lever of this class.
THIRD CLASS LEVERS
These are simple machines that have the effort placed between the load and the fulcrum. The effort always travels a shorter distance and must be greater than the load. The FOREARM is a third-class lever. The hand holding the weight is lifted by the bicepd muscle of the upper arm which is attached to the forearm near the elbow. The elbow joint is the fulcrum.
In a compound lever simple machine, two or more levers are combined, usually to decrease the effort. By applying the principle of the compound lever, a person could used the weight of one hand to balance a load weighing a ton.