Step Pulley Term Project Report

7/31/2019 Step Pulley Term Project Report

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3RD SEMESTER, MECHANICAL ENGG;

TERM PROJECT REPORT

SEMESTER TERM PROJECT REPORT ON;

MANUFACTURING PROCESS OF STEP

PULLEY BY MACHINING:

1. UW-09-ME-BE-001

2. UW-09-ME-BE-032

3. UW-09-ME-BE-036

4. UW-09-ME-BE-044

Dr. MUHAMMAD RIAZ BHATTI

Wah Engineering College

UNIVERSITY OF WAH

25 JANUARY 2011


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TERM PROJECT REPORT

Looking at the present situation we often search for devices used for lifting of bodies,

changing direction of the motion of a component , driving the shafts and chains through

some specific RPMs, or increasing the circulatory motion of a machine, all these multiple

functions are done through pulleys which is itself a simple type of machine. Step pulley is a

basic type of pulley having more than one groove and has one concentric unit. Steps are

like stairs as we preceded the height of stairs are increases, in engineering drawing

language we say the diameter of each step is increases if we go from the small step to the

large. Steps may be 3, 4, 5, 6 and as per requirement. Our project is three steps v pulley.

The V indicates the belt drive; our project can be used for the application of V belt drives

purposes. First we draw a rough sketch on paper then we neatly draw the sketch on

AutoCAD with proper dimensions. These step pulleys are many utilized in high speed

rotating machines. It is used to increase the speed as per requirement. Working of Step

pulley is similar to Gears.

This project is dedicated to

our PARENTS AND TEACHERS without

whose support and prayers we are

nothing.


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TERM PROJECT REPORT

First of all we would like to thank Allah Almighty for giving us the chance and the

courage to carry out this project. we have achieved a lot from this project so we keep

on praying to Allah for more.

Secondly, we would like to thank our POFIT instructors for all the support and

guidance without which we would have never gone so far.

Thirdly we would like to thank WEC lab Staff for their technical advices.

Pulley is a simple machine commonly used as wheels and axles with a groove around

the outside. A pulley needs a rope, chain or belt around the groove to make it do work.

Also used for lifting heavy weights easier by redirecting force. Pulleys let you move loads

up, down, or sideways. Pulleys are classified on the bases of position, numbers, and

grooves.

On the basis of position pulleys are classified as;

1. FIXED PULLEYS:


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TERM PROJECT REPORT

A fixed pulley is the only pulley that when used individually, uses more effort than

the load to lift the load from the ground. The wheel does not move. Fixed pulleys change

the direction of the effort force. It does not increase the size of the effort force.

The advantage of the fixed pulley is that you do not have to pull or push the pulley up and

down. The disadvantage is that you have to apply more effort than the load.

2. MOVABLE PULLEYS:

A movable pulley is a pulley that moves with the load. The movable pulley allows the effort

to be less than the weight of the load. The movable pulley also acts as a second class

lever. The load is between the fulcrum and the effort. The main disadvantage of a movable

pulley is that you have to pull or push the pulley up or down. The main advantage of a

movable pulley is that you use less effort to pull the load.


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TERM PROJECT REPORT

On the basis of geometry pulleys are;

1. Flat pulley:

Rotary motion is the most common type of motion for a shaft or an axle. One way in which an

engineer uses rotary motion is by transmitting it from one shaft to another when the shafts are

parallel. This can be done by using pulleys and belts. A pulley is a wheel which may or may not

have a grooved rim.

The figure below shows a stacked vee pulleys and vee belts often used in car engines.

2. TOOTH PULLEY;

In machines where a positive drive is essential and no slip between belt and pulleys can be accepted,

a toothed belt and pulley is used. Toothed belts are mainly used for timing mechanisms, where quiet,

positive (no slip) drive is required. The figure below shows a toothed belt and toothed pulleys used


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TERM PROJECT REPORT

to drive a camshaft in a motor car engine.

On the basis of numbers pulleys are classified as;

1. COMPOUND PULLEYS:

Combined pulley makes life easier as the effort needed to lift the load is less than half the

weight of the load. The main advantage of this pulley is that the amount of effort is lessthan half of the load. The main disadvantage is it travels a very long distance.

ALSO KNOWN AS COMBINED PULLEYS.OR BLOCK AND TACKLE.


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TERM PROJECT REPORT

On the basis of grooves pulleys are classified as;

STEP PULLEYS:

A step pulley is a system of pulleys made up of many different sizes. The typical step

pulley consists of a two- to four-pulley configuration. This type of step pulley is found on

equipment such as adrill presswhere different operational speeds can be produced simply

by changing the belt to a different pulley size. The step pulley is always operated in pairs,

and when the belt is changed on one pulley, it is also changed on the corresponding pulley

on the other side of the belt.

PROCESS FOR MANUFACTURING STEP PULLEYS:

Most step pulley assemblies are cast from liquid materials; some of the very high-

end pulleys, however, are forged from solid billet material such as aluminum or

steel. The billet step pulley is much more true when spinning than a cast version;

there is a great cost difference between the two, however, with the billet costing
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TERM PROJECT REPORT

much more. Some designs utilize separate and independent pulleys to make up the

arrangement, although this is not a true step pulley.

While most of the step assemblies are configured for V-belt use, there are also

some step pulleys which utilize flat belts. This type of step system can be switched

or changed on the fly and is found in lathe transmissions or some milling machines.

Theflat beltpulleys are typically always forged from billet stock and operate much

more smoothly than the V-belt design. The V-belt type of pulley is favored in higher

torque applications, though, due to the ability of a V-belt to grip the pulley with more

strength.

BASIC PURPOSE (ADVENTAGEs) OF STEP PULLEY:

1. When it has been determined that the speed should be

regulated on a particular step pulley equipped machine, the

process of adjusting the speed is usually an easy one. With the

motor in the off position, open the belt cover. Take note of

where the belt is currently positioned on the pulleys.

Remember, a large pulley driving a smaller pulley will result in

more power but less speed output. Conversely, a small pulley

driving a large pulley will have more speed output but less

power.

2. Once the proper pulley system has been determined for the

desired outcome, the belt cover can be closed and the machine

once again turned on. Now the machine can be operated at the

proper speed for the desired effect. Sanding projects, for

example are typically conducted at a faster speed than a cuttingor shaping project. On a typicalwood latheproject, the pulleys

may be changed several different times.

3. When it has been determined that the speed should be

regulated on a particular step pulley equipped machine, the

process of adjusting the speed is usually an easy one.

4. One exercise that strengthens the coracobrachialis is the

incline cable chest fly. To perform the incline fly, one should set
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TERM PROJECT REPORT

both pulleys on a dual cable column machine to their lowest

setting and stand midway between them and slightly in front.

Wood lathe machine

5. The other practical example in which step pulley used is drill

press. Where different operational speeds can be produced

simply by changing the belt to a different pulley size. The step

pulley is always operated in pairs, and when the belt is changed

On one pulley, it is also changed on the corresponding pulley

On the other side of the belt.


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TYPICAL DRILL PRESS.

Close look------


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Above are the various parts in drill press where step pulley is

inserted.


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Casting requires proper pattern and mould.

Proper molten metal and proper arrangement of gating system that is riser, runner

and sprue.

Giving proper time to the molten metal to solidify and careful about shrinkage and

shrinkage allowance.

Before casting calculate all the factors acting during the process to get a good cast.

After cast proper finishing through autos and other equipments.


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If there is any mistake in pattern, gate system, molten metal

properties then cast will be,


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I remind that material used for our project is Aluminum.

And we manufacture this project through machining.Machines involved are CNC, LATHE AND DRILL

MACHINES.

First we draw a drawing in AUTOCAD specifying the top and front view of our

project having three grooves or steps.

Three steps are manufactured on CNC and Lathe machines.

First step have 22mm length and have diameter of

114mm (4.5 inches approximately). 2nd step have 20mm length and have diameter of

76mm.

3rd step have length and diameter is

Through Drill machine having drill of (approximately half inch) diameter, we

drill at the center of the circular job. This hole is done for passing of shaft or spindles

etc.

In each step the depth of groove is constant i.e. . and the grooves are forvee.belt drive having angle of


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Question:

We choose machining method because it is easier than

casting. For project point of view machining method is better

than casting. Casting requires much equipment. First pattern is

required then mould of the required pattern is required. After

this suitable metal free of hazards are melted and pour through

the sprue into the mould goes through gating system. Then

time of solidification requires, so have lengthy process but

casting is better process in point of production point of view.

Merits of machining method is only one reason,Step pulleys through machining manufacturing method have

well finish than casting.

Step pulley with 4 grooves steps

Step Pulley Term Project Report

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