step pulley term project report
TRANSCRIPT
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7/31/2019 Step Pulley Term Project Report
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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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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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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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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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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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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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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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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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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