Abstract
“PNEUMATIC THREE AXIS TRAILER ” is nothing but one of the Lifting system in automobile at the time of emergency. In this Lifting system pneumatically operated one. Here the additional pneum neuma atic tic cy cyli lind nde er and Contr ntrol Valve lve is provi ovided in the automobile itself. In this project, the Control Valve is used to activatedeactivate the !ir input. "he Valve is #$%& at the time of emergency' the compressed air goes to the pneumatic cylinder. "hen the compressed compressed air passes through through the tube, and then pushes the pneumatic cylinder, so that the Lifting is applied at the time of Valve in “$%” position (i.e.)*mergency time+. "he speed of the pneumatic cylinder is varied by using ocontrol valve. "his is the -ay of controlling Lifting speed of the "railer "railer at the time of emergency emergency.. In our project, -e have to apply this neumatic /odern "railer /echanism in Load Lifting Vehicles.
1
1. INTRODUCTION
!utomation can be achieved through computers, hydraulics, hydraulics, robotics, etc., of these sources, hydraulics form an attractive medium. !utomation plays an important role in automobile. %o-adays almost all the automobile vehicle is being atomi0ed in order to product the human being. "he automobile vehicle is being atomi0ed for the follo-ing reasons1
"o achieve high safety
"o "o reduce reduce man po-er po-er
"o "o increase increase the e2ciency e2ciency of the vehicle
"o "o reduce reduce the -or3 -or3 load
"o "o reduce reduce the fatigue fatigue of -or3er -or3ers s
"o "o high responsibili responsibility ty
Less /aintenance cost
2
2.1 PNEUMATICS:
neumatics is something that you probably 3no- very little about yet come across every day -ithout even realising it. 4ome e5amples of everyday pneumatic systems are sho-n belo-. Homany do you recognise6
Figure 1
Pneumatics is also used a lot in industry and you would expect to see pneumatic systems in factories, production lines and processing plants. It can be used to do lots of different jobs such as moving, holding or shaping objects. o bjects.
3
MOVE
HOLD
FORM
PROCESS
Figure 2
4
Every one of these pneumatic pneu matic systems makes use of compressed air . Compressed air is uite simply the air that we breathe forced or suashed into a smaller space. !e can use the energy stored in this compressed air to do things. "o understand understand how compressed air is able to do things, let#s think of a ball. If we blow up the ball so that it is full, it will will contain a lot of compressed air. If we bounce the ball, it will bounce very high. $owever, if the ball is burst then the compressed air will escape and the ball will not bounce as high. %uite simply, simply, the ball bounces because it is using the energy stored in the compressed air.
Figure 3
&asically, &asically, all pneumatic systems make use of compressed air to do work. !e can show this in a systems diagram.
Compressed air
Pneumatic system
Figure 4
5
!ork
ADVANTAGES OF PNEUMATICS
"here are usually lots of different ways to carry out a task, so it is important to understand some of the reasons for choosing pneumatic systems. Clean Pneumatic systems are clean because they use compressed air. !e know already that this is just the air we breathe forced into small spaces. If a pneumatic system develops a leak, it will be air that escapes and not oil. "his air will not drip or cause a mess and this makes pneumatics suitable for food production lines. Safe Pneumatic systems are very safe compared to other systems. !e cannot, for example, use electronics for paint spraying because many electronic componen ts produce sparks and this could cause the paint to catch fire.
It is important, however, that we look after and maintain the different components. It is also important that we follow the correct safety rules. Reliale Pneumatic systems are very reliable and can keep working for a long time. 'any companies invest in pneumatics because they know they will not have a lot of breakdowns and that the euipment will last for a long time. E!"n"#i!al If we compare pneumatic systems to other systems, we find that the y are cheaper to run. "his is because the components last for a long time and because we are using compressed air. 'any factories already have compressed air for other reasons. Fle$ile (nce you have bought the basic components, you can set them up to carry out different tasks. Pneumatic systems are easy to install and they do not need to be insulated or protected like electronic systems. Assignment 1 ). *ive three examples of the everyday use of pneumatics. +. Choose one of your examples from uestion ). raw a system diagram and describe how it makes use of compressed air. -. !hat is compressed air /. "hink about blowing up a balloon. !hat happens to the balloon if you let it go !hy does this happen 0. *ive two reasons why pneumatic systems are used in industry.
%
SUPP&'ING COMPRESSED AIR !e know already that pneumatic systems need compressed air to make them work. 1 bicycle pump can produce compressed air. "his is all right for inflating the tyres on your bicycle, but can you imagine trying to blow up all the tyres on a lorry using this 2ou would soon become tired, exhausted even. In order to supply pneumatic systems with compressed air we use a machine called a compressor. Compressors come in lots of different shapes and si3es but they all work in the same way.
Figure 5
1 pump that is driven by a motor, sucks in air from the room and stores it in a tank called the receiver. 2ou will be able to hear the compressor when it is running. 4ometimes though, it will stop because the receiver is full. Ask your teacher to see the compressor that will be supplying your compressed air. 5ot everyone in your class could connect directly to the compressor, as this is not practical. Instead, a pipe takes the compressed air from the receiver to various points around the room. !e would normally connect a device called a manifold to these points. "he manifold lets us connect lots of components to the compressed air. It also lets us switch our circuits on and off. ON
OFF
Figure %
(
ACTUATORS
"here are a number of different ways that we can operate a -6+ valve. "he most common way is by using a push button. &y pressing the button, the valve changes to the actuated state and allows main air to flow through to other components. If we release the button, a spring inside returns the valve to its off state. "he symbol for a push button, spring return -6+ valve is shown below.
Figure 1)
&elow is a list of the most common types of actuators. "hey are always drawn onto the standard symbol for the -6+ valve.
PLUNGER
ROLLER TRIP
PUSH BUTTON
SOLENOID
LEVER
DIAPHRAGM
FOOT ROLLER
PEDAL
PILOT AIR
SPRING
Figure 2*
+
SIMP&E CIRCUITS USING SING&E,ACTING C'&INDERS
1 city7centre car park has a barrier system to prevent people parking illegally. "he car park attendant checks all the cars entering and leaving the car park. "he barrier is raised and lowered by a single7acting cylinder. "he attendant pushes a button to operate the system.
Figure 21
"he systems diagram is shown below. Press button
-6+ 8alve
Cylinder
Figure 22
"he pneumatic circuit is shown below.
Figure 23
)
&arrier raises
!hen the button is pressed, the valve changes state and supplies air to the single7acting cylinder. "his causes the piston to outstroke with enough force to raise the barrier.
1*
Figure 24
!hen the button is released, the valve returns to its original state and the piston is able to instroke ready for the process to begin again.
9a: 9b: 9c: 9d: 9e:
ASSIGNMENT 3 &uild the circuit for raising and lowering the car park barrier. Press the button on the valve and keep it pressed. Explain what happens. ;elease the button and explain what happens.
T,PIECE 1 "7piece or "7connector is a very simple component that lets us split or divide airflow. It can be very useful if you want two cylinders to operate at the same time. AIR OUT
AIR OUT
AIR IN
Figure 25
(n circuit diagrams, the "7piece is identified by a dot. "7piece
11
Figure 2%
12
Assignment 4 ). 1 delivery lorry uses a pneumatic braking system. "he brakes operate when the driver presses the foot brake. "wo single7acting cylinders should outstroke at the same time and press against the wheels. "he pneumatic circuit is shown below.
Figure 2(
9a: &uild and test the circuit shown. 92ou can use a push button, spring return -6+ valve instead of a foot pedal.: 9b: Explain the purpose of the "7piece. +. =our single7acting cylinders are used to clamp large nameplates to a table to allow them to be engraved. 1ll four cylinders must operate at the same time.
A IR S U P P L Y
Figure 2+
9a: esign a pneumatic system to solve this problem. 9b: &uild and test your solution. 9c: Explain your choice of actuator.
13
SIMP&E CIRCUITS USING DOU-&E,ACTING C'&INDERS
!e know already that double7acting cylinders do n ot have a spring inside to return them to their original position. "his means that we need to use compressed air to outstroke and instroke the piston. (ne way to do this is to connect a -6+ valve to either side of the double7acting cylinder. ;emember our car park problem. 4omeone has suggested changing the single7acting cylinder to a double7acting one.
Figure 2)
"he pneumatic circuit would now look like this.
Valve A
Valve B
Figure 3*
!hen the attendant actuates valve 1 by pressing the button, the double7acting cylinder outstrokes and lifts the barrier. It stays in this position until valve & is actuated. "his allows the piston to instroke and the barrier is lowered.
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Assignment 5 9a: &uild the circuit shown above for raising and lowering the barrier. 9b: Press the button on valve 1 to outstroke the cylinder. oes the piston instroke when you release the button 9c: Press the button on valve &. !hat happens to the cylinder 9d: !hat happens when you press both buttons at the same time 9e: 1ctuate valve 1 again and then try pushing against the piston. !hy is it so easy to move 9f: !hat type of problems could this cause in this particular circuit
15
5.2 /al/e0
"here are many problems when controlling a double7acting cylinder with two -6+ valves. 2ou should have discovered from the last circuit that it is e asy to push or pull the piston. "his is because you do not have a constant supply of air to keep the piston in place. !hen you actuate the -6+ valve, it outstrokes the piston. !hen the -6+ valve is not actuated, air is free to escape or exhaust back through the valve. "his means that any force or effort placed on the piston will make it move easily.
Figure 31
1 further disadvantage is that the -6+ valve needs to be actuated until the double7acting cylinder has fully outstroked or instroked. ;eleasing the valve before the stroke is complete will mean the piston will stop short of its final position. !e have greater control over a double7acting cylinder if we control its outstroke and instroke using a 06+ valve. "his valve has five ports and two states of operation. "he ports are always numbered in the same way. P"r 1 #ain air "his port is connected to main air just like a -6+ valve. P"r 2 "uu !"nne!i"n "his port is usually connected to instroke a double7acting cylinder. P"r 3 e$au0 "his port allows air trapped in the double7acting c ylinder to escape. ;emember, for the cylinder to instroke and outstroke, air on the other side of the piston must be allowed to escape. If this did not happen, the piston would not move. P"r 4 "uu !"nne!i"n "his port is usually connected to outstroke a double7acting cylinder. P"r 5 e$au0 1gain, this port lets the air on the other side of the piston escape. 1%
1 06+ valve has two states of operation. (ne state supplies air to outstroke a double7acting cylinder and the other state will cause it to instroke.
1(
STATE 1 INSTROE In this state, the main air flows through the valve from port ) to port +. 1ny air within the cylinder is able to exhaust through the valve from port / to port 0. In this state, a 06+ valve will cause a double7acting cylinder to instroke or hold the piston in the negative position. "his means that air is always being supplied to the cylinder.
4tudy the symbol below and ensure that you understand how the air flows through the valve. AIR FROM
AIR TO
CYLINDER
CYLINDER
4
2
5
1
3
Figure 32 Sae 2 "u0r"6e In this state, the main air flows through the valve from port ) to port /. 1ny air on the other side of the piston is able to exhaust through the valve from port + to port -. In this state, a 06+ valve will cause a double7acting cylinder to outstroke and will hold it in the positive position.
4tudy the symbol below and ensure that you understand how the air flows through the valve. AIR TO
AIR FROM
CYLINDER
CYLINDER
4
2
5
1
3
Figure 33
"he complete symbol for a 06+ valve is shown. "he cylinder, main air and exhaust lines are only ever drawn on one half of the symbol, depending on which part is active in the circuit. It is usual, however, to draw the symbol so that it would hold a double7acting cylinder in the negative position.
1+
Figure 34 Pil" air 06+ valves can be operated or actuated in the same way as -6+ valves. $owever, the most common way of actuating a 06+ valve is by pilot air . 1 pilot air 06+ valve will change state when a brief air signal acts at either end of the valve. "his signal is most often supplied from a -6+ valve. In the example shown below, the button on valve 1 only needs to be pressed for a moment in order to change the state of the 06+ valve. "he 06+ valve supplies the double7acting cylinder with air to make it outstroke.
Valve A
Figure 35
5otice that the pilot airlines to the 06+ valve are drawn as broken or dashed lines to distinguish them from the other air lines in the circuit.
1)
Assignment 6 ). (ur car park barrier is gradually improving. "he circuit has been changed to look like the one shown in figure -0. 9a: &uild and test the circuit. 9b: Produce a list of all the components used. 9c: escribe how the circuit works. 9d: 1 door entry system is controlled by pneumatics. "he system makes use of a double7acting cylinder. Part of the circuit diagram is shown below.
C
A
B
Figure 3%
+. 9a: 5ame each of the components 1, & and C. 9b: Complete the diagram so that the door will open and close. 9c: escribe how the circuit operates.
2*
"he -ord #pneuma& comes from 7ree3 and means breather -ind. "he -ord pneumatics is the study of air movement and its phenomena is derived from the -ord pneuma. "oday pneumatics is mainly understood to means the application of air as a -or3ing medium in industry especially the driving and controlling of machines and e8uipment. neumatics has for some considerable time bet-een used for carrying out the simplest mechanical tas3s in more recent times has played a more important role in the development of pneumatic technology for automation. neumatic systems operate on a supply of compressed air -hich must be made available in su2cient 8uantity and at a pressure to suit the capacity of the system. 9hen the pneumatic system is being adopted for the :rst time, ho-ever it -ills indeed the necessary to deal -ith the 8uestion of compressed air supply. "he 3ey part of any facility for supply of compressed air is by means using reciprocating compressor. ! compressor is a machine that ta3es in air, gas at a certain pressure and delivered the air at a high pressure. Compressor capacity is the actual 8uantity of air compressed and delivered and the volume e5pressed is that of the air at inta3e conditions namely at atmosphere pressure and normal ambient temperature. "he compressibility of the air -as :rst investigated by ;obert ?@ and that found that the product of pressure and volume of a particular 8uantity of gas. 21
"he usual -ritten as V A C
(or+ BVB A @V@
In this e8uation the pressure is the absolute pressured -hich for free is about =.D si and is of courage capable of maintaining a column of mercury, nearly EF inches high in an ordinary barometer. !ny gas can be used in pneumatic system but air is the mostly used system no- a days. 2.2 SELECTION OF PNEUMATICS:
/echani0ation is broadly de:ned as the replacement of manual eGort by mechanical po-er. neumatic is an attractive medium for lo- cost mechani0ation particularly for se8uential (or+ repetitive operations. /any factories and plants already have a compressed air system, -hich is capable of providing the po-er (or+ energy re8uirements and the control system (although e8ually pneumatic control systems may be economic and can be advantageously applied to other forms of po-er+. "he main advantage of an all pneumatic system are usually economic and simplicity the latter reducing maintenance to a lolevel. It can also have out standing advantages in terms of safety. 2.3 PRODUCTION OF COMPRESSED AIR:
neumatic systems operate on a supply of compressed air, -hich must be made available. In su2cient 8uantity and at a pressure to suit the capacity of the system. 9hen pneumatic system is being adopted for the :rst time, ho-ever it -ills indeed the necessary to deal -ith the 8uestion of compressed air supply. 22
"he 3ey part of any facility for supply of compressed air is by means using reciprocating compressor. ! compressor is a machine that ta3es in air, gas at a certain pressure and delivered the air at a high pressure. Compressor capacity is the actual 8uantity of air compressed and delivered and the volume e5pressed is that of the air at inta3e conditions namely at atmosphere pressure and normal ambient temperature.
Clean condition of the suction air is one
of the factors, -hich decides the life of a compressor. 9arm and moist suction air -ill result in increased precipitation of condense from the compressed air. Compressor may be classi:ed in t-o general types1 =. ositive displacement compressor. 2. Turbo co!r"ssor Pos#t#$" %#s!&ac""'t co!r"ssors are most fre8uently
employed for compressed air plant and have proved highly successful and supply air for pneumatic control application. "he types of positive compressor =. ;eciprocating type compressor @. ;otary type compressor Turbo co!r"ssors are employed -here large capacity of
air re8uired at lo- discharge pressures. "hey cannot attain pressure necessary for pneumatic control application unless built in multistage designs and are seldom encountered in pneumatic service. 23
2.( RECIPROCATIN) COMPRESSORS:
"he various factors -hich determine the choice of material are discussed belo-. 3.1 Pro!"rt#"s:
"he material selected must posses the necessary properties for the proposed application. "he various re8uirements to be satis:ed can be -eight, surface :nish, rigidity, ability to -ithstand environmental attac3 from chemicals, service life, reliability etc. "he follo-ing four types of principle properties of materials decisively aGect their selection 24
a. hysical b. /echanical c. rom manufacturing point of vied. Chemical "he various physical properties concerned are melting point, "hermal Conductivity, 4peci:c heat, coe2cient of thermal e5pansion, speci:c gravity, electrical Conductivity, /agnetic purposes etc. "he various /echanical properties Concerned are strength in tensile, compressive shear, bending, tensional and buc3ling load, fatigue resistance, impact resistance, elastic limit, endurance limit, and modulus of elasticity, hardness, -ear resistance and sliding properties. 3.2 Ma'u*actur#'+ Cas":
4ometimes the demand for lo-est possible manufacturing cost or surface 8ualities obtainable by the application of suitable coating substances may demand the use of special materials. 3.3 ,ua&#t- R"u#r"%:
"his generally aGects the manufacturing process and ultimately the material. or e5ample, it -ould never be desirable to go for casting of a less number of components -hich can be fabricated much more economically by -elding or hand forging the steel. 3.( A$a#&ab#&#t- o* Mat"r#a&: 25
4ome materials may be scarce or in short supply. It then becomes obligatory for the designer to use some other material -hich though may not be a perfect substitute for the material designed. "he delivery of materials and the delivery date of product should also be 3ept in mind. 3./ S!ac" Co's#%"rat#o':
4ometimes high strength materials have to be selected because the forces involved are high and the space limitations are there. 3.0 Cost:
!s in any other problem, in selection of material the cost of material plays an important part and should not be ignored. 4ome times factors li3e scrap utili0ation, appearance, and non)maintenance of the designed part are involved in the selection of proper materials.
(. COMPONENTS AND DESCRIPTION (.1 MAOR PARTS:
"he major parts PNEUMATIC THREE AXIS MODERN TIPPER” are described belo-1
!ir compressor
Jirection Control Valve
Cylinder
Connecting hoses 2%
lo- control valve
;otating lates
(.1.1AIR COMPRESSOR:
"he main function of the air compressor is to compress the air up to the re8uired pressure. "he ma5imum capacity of the compressor is =F3=F to =@ 3=F %m@. "his is a t-o stages or t-o)cylinder reciprocating air compressor. "he t-o cylinders are for lo- and high compression. "he air pressure is measured at various places by the use of pressure gauges. V)belt and pulley are used to drive the compressor. Compressors can be broadly classi:eds into t-o groups. "hey are1
ositive Jisplacement Compressor
Jynamic Compressors
(.1.1.1Pos#t#$" D#s!&ac""'t Co!r"ssor:
4uccessive volumes of air isolated and then compressed to a higher pressure. "here are essential t-o forms of positive displacement compressor, reciprocating and rotary. (.1.1.2D-'a#c Co!r"ssors: 2(
"hese are rotary continuous machines in -hich a high speed rotating element accelerates the air and converts the resulting velocity head into pressure. ositive displacement compressors -or3 on the principle of increasing the pressure of a de:nite volume in an enclosed chamber. Jynamic (turbo+ compressor employs rotating vanes or impellers to impart velocity and pressure to the o- of the air being handled. "he pressure comes from the dynamic eGects such as centrifugal force.
(.1.2 PRESSURE )AU)E:
ressure gauge is used for measuring the outlet pressure of air from the compressor. "he gauge used is
(.1.3 DIRECTIONAL CONTROL ALES: (.1.3.1 P'"uat#c $a&$"s:
"he pneumatic cylinder is regulated and controlled by pneumatic valves. "hese valves are actuated manually, mechanically, electrically, pneumatically, and by various combined mode of actuation.
2+
(.1.3.2N""% o* a&$"s: DIRECTIONAL CONTROL ALES "o control the to and fro
motion of cylinder, the uid energy has to be regulated, controlled and reversed -ith a predetermined se8uence in a pneumatic system. 4imilarly one may have to control the 8uantity of pressure and o- rate to generate the desired level of force and speed of actuators. "o achieve these functions, valves are used. Valves are uid po-er elements used for controlling and regulating the -or3ing medium. "he main functions of the valves are1 •
4tart and stop the uid energy
•
Control the direction of o- of compressed air
•
Control the o- rate of the uid
•
Control the pressure rating of the uid
!lthough various types of valves are available, they are mainly classi:ed as belo-1 •
Jirection control valves
•
Jirection control chec3 valves
•
lo- control valves
•
ressure control valves
2)
"he main purpose of a valve in a pneumatic circuit is to control outputs. Valves can be divided into a number of groups according to -hat they control. (.1.3.3 D#r"ct#o'a& co'tro& $a&$"s:
Jirectional control valve on the receipt of some e5ternal signal, -hich might be mechanical, electrical or a uid pressure pilot signal, charges the direction of or stops, or starts the o- of uid in some part of the pneumatichydraulic circuit.
(.1.3.( Pr"ssur" Co'tro& a&$"s:
"hese are used to control the pressure in part of the pneumatichydraulic circuit. (.1.3./ F&o4 Co'tro& a&$"s:
"hese are used to control the rate of o- of a uid through the valve. ! directional control valve on the receipt of some, e5ternal signal, -hich might be mechanical, electrical or a uid pilot signal, changes the direction of stops, or starts the o- of uid in some part of the pneumatichydraulic circuit. "hey can be used to carry out such functions as1 =. Controlling the direction of motion of an actuator @. 4electing alternative o- paths for a uid. E. 4topping and starting the o- of uid. 3*
Carrying out logic functions such as !%J, $;, %!%J (.1.3.0 Actuators:
!n actuator is a device that is used to apply a force to an object luid po-er actuators can be classi:ed into t-o groups1
Linear actuators are used to move an object or apply a force in a straight line.
Linear actuators can be divided into t-o types.
"hey are1 =. 4ingle acting cylinders @. Jouble acting cylinders ! single acting cylinder is po-ered by uid for the movement of the piston in one direction -ith it being returned in the other direction by an internal spring or an e5ternal force, a double acting cylinder is po-ered by uid in both directions.
;otary actuators are used to move an object in a circular path. ;otary actuators are the uid po-er e8uivalent of an electric motor.
(.1.( PNEUMATIC C5LINDERS:
Cylinders are the one, -hich oGers the rectilinear motion to mechanical elements. Cylinders are classi:ed as light, medium, and heavy duty -ith respect to their application. (.1.(.1S#'+&" Act#'+ C-&#'%"rs: 31
In this type, the cylinder can produce -or3 only in one direction. "he return movement of the piston is eGected by a built in spring or by application of an e5ternal force. "he spring is designed to return the piston to its initial position -ith a su2ciently high speed. "ypes of single acting cylinders1 •
Jiaphragm cylinder
•
;olling diaphragm cylinder
(.1.(.2Doub&" Act#'+ C-&#'%"r:
"he force e5erted by the compressed air moves the piston in t-o directions in a double acting cylinder. "hey are used particularly -hen the piston is re8uired to perform -or3 not only on the advance movement but also on the return. In principle, the stro3e length is unlimited, although buc3ling and bending must be considered before -e select a particular si0e of piston diameter, rod length and stro3e length. 9e use cylinders that are double acting type (i.e.+ the compressed air can be passed to either end of the cylinder. "hese cylinders are made up of cast iron.
32
(.1./ SEALS: (.1./.1 A#r S"a&:
!ir seal is used to prevent the lea3age of air pressure from the cylinder. %ormally it is made up of neoprene rubber. If there are any air lea3ages in the system, it -ill reduce the e2ciency. (.1./.26#!"r S"a&:
9iper seal is provided at the entrance of the cylinder to avoid dust materials from the environment. It is made up of neoprene rubber. (.1./.3O7 R#'+:
"he “$” rings are :tted into the grooves of piston to maintain perfect seal bet-een the piston and the cylinder -all. "hey are mostly made up of neoprene rubber. (.1.0 C5LINDER TECHNICAL DATA: 8arr"&:
It is made of cold dra-n aluminimum honed to @mm. P#sto' Ro%:
/.4. hard Chrome plated S"a&s:
%itrile (
Cast iron graded :ne grained from @mm to EFFmm P#sto':
!luminium. M"%#a:
!ir. 33
T"!"ratur" Ra'+":
FNc to ONc Cus9#o's:
!djustable standard on FFmm bore and above. (.1. CONNECTORS:
In our system there are t-o types of connectors used' one is the hose connector and the other is the reducer. Hose connectors normally comprise an adapter (connector+ hose nipple and cap nut. "hese types of connectors are made up of brass or !liminium or hardened steel. ;educers are used to provide inter connection bet-een t-o pipes or hoses of diGerent si0es. "hey may be :tted straight, tee, “V” or other con:gurations. "hese reducers are made up of gunmetal or other materials li3e hardened steel etc. (.1.; FLO6 CONTROL ALE:
In any uid po-er circuit, o- control valve is used to control the speed of the actuator. "he oe control can be achieved
34
(.1.<8EARIN) 6ITH 8EARIN) CAP:
"he bearings are pressed smoothly to :t into the shafts because if hammered the bearing may develop crac3s. at &"ast to L"o'ar%o %a #'c#? t9"#r %"s#+' a'% a'u*actur" 9as b"co" r"ar>ab&- so!9#st#cat"%. T9#s t"c9'o&o+- 4as brou+9t to #ts ! r"s"'t stat" o * !"r*"ct#o' o'&- a*t"r a &o'+ !"r#o% o* r"s"arc9 a'% %"$"&o!"'t. T9" b"'"@ts o* suc9 s!"c#a&#="% r"s"arc9 ca' b" obta#'"% 49"' #t #s !oss#b&" to us" a sta'%ar%#="% b"ar#'+ o* t9" !ro!"r s#=" a'% t-!". Ho4"$"r? suc9 b"ar#'+s ca''ot b" us"% #'%#scr##'at"&- 4#t9out a car"*u& stu%- o* t9" &oa%s a'%
35
o!"rat#'+ co'%#t#o's. I' a%%#t#o'? t9" b"ar#'+ ust b" !ro$#%"% 4#t9 a%"uat" ou't#'+? &ubr#cat#o' a'% s"a&#'+. (.1.1 6HEEL ARRAN)EMENT:
"he -heels are :tted to the body of the vehicle -ith the help of end bearing and bearing caps. "he -heels are made up of :ber material. (.1.11 TIPPER 8OD5:
"he tipper body is made up of mild steel sheet metal. "his frame is loo3 li3e a small model trailer. (.1.12 ROTATIN) PLATES:
"he rotating plates are :5ed in the bottom the trailer body, so that the cylinder -ill rotates in the re8uired side. "he plates are made up of mild steel materials.
CHAPTERB . DESI)N AND DRA6IN)S .1
PNEUMATIC C5LINDER
.1.1 D"s#+' o* P#sto' ro%:
Load due to air ressure. Jiameter of the iston (d+ A ressure acting (p+
3%
F mm
A
? 3gfcmP
A
? QF.>O=
A
.OO? bar F.OO?%mm@
A /aterial used for rod A
C
(data
boo3 page no =.=@ + Rield stress (Sy+
A
E? 3gfmmP
A
E?Q>O.=
A
EE=.? bar EE.=?%mm@
A factor of safety
A
@( data boo3
page.no O.=>+ orce acting on the rod (+
A
ressure
5 !rea A
p 5 (TdP +
A
F.OO? 5 U( T 5 FP
A
DE>.? %
A
Sy F 4
A
EE.=? @
+
Jesign 4tress(Sy+
A Wd
A
3(
=D?.%mm@ XY ZSy[
A
X (QDE>.?+
YZ=D?.[ W /inimum diameter of rod re8uired for the load A
@.E
mm 9e assume diameter of the rod
A
= mm
.1.2 D"s#+' o* c-&#'%"r t9#c>'"ss:
/aterial used
A
!ssuming internal diameter of the cylinder \ltimate tensile stress
Cast iron A
F mm
A
@F
%mmP 9or3ing 4tress
A
\ltimate tensile stress
A
A
@F
A
?@. %mm@
factor of safety !ssuming factor of safety 9or3ing stress ( f t + !ccording to #L!/*4 *]\!"I$%& /inimum thic3ness of cylinder ( t +
A ri UX(f t^p+(f t)p+)=
9here, ri
A
inner radius of cylinder in cm.
f t
A
9or3ing stress (%mmP+
p
A
9or3ing pressure in %mmP
W 4ubstituting values -e get, t
A
@.F UX (?@. ^ F.OO?+ (?@. M
A
F.@Dmm
F.OO?+ )= t
3+
9e assume thic3ness of cylinder A
@. mm
Inner diameter of barrel
A
F mm
$uter diameter of barrel
A
F ^ @t
A
F ^ ( @ 5 @. +
A
mm
A
ressure 5 area
A
p 5 T (dP+
A
F.OO? 5 (T + 5 (F+P
A
DE>.? %
A
(T+ (d p+P 5 f t
.2 DESI)N OF PISTON ROD: .2.1 D#a"t"r o* P#sto' Ro%:
orce of piston ;od (+
!lso, force on piston rod (+
A
(T+ 5 (dp+P 5
DE>.?
A
(T+ 5 (dp+P 5
W dpP
A
DE>.? 5 (T+ 5
?@. ?@ (=?@.+ A dp
A
=
E.O mm
A
= mm
A
=?F mm
.2.2 L"'+t9 o* !#sto' ro%:
!pproach stro3e 3)
Length of threads
A
@ 5 @F
A
Fmm *5tra length due to front cover
A
=@ mm
*5tra length of accommodate head
A
@F mm
"otal length of the piston rod
A
=?F ^ F ^ =@ ^
@F A
@E@ mm
A
@EF mm
.3 DESI)N OF 8ALL 8EARIN):
A
E mm
A
=@ mm
Inner Jiameter of the
A A
= mm
Corner radii on shaft
and housing r_
A
=(rom design
data boo3+ /a5imum 4peed
A
=,FFF rpm
A
(J ^ d+ @
(rom design data boo3+ /ean Jiameter (dm+ dm
4*
A
(E ^ =+ @
A
@ mm
.( 6AHL STRESS FACTOR: rom design
data boo3 page.no D.=FF `s
A
C M = ^ C M
A
C
( @.E+ )= ^ F.? ( @.E +)
`s
F.?
A
@.E
=.O
./ SPECIFICATION ./.1 Doub&" act#'+ !'"uat#c c-&#'%"r T"c9'#ca& Data
4tro3e length 1
Cylinder sto3er length =?F mm A
F.=? m ]uantity
1
=
4eals
1
%itride (
*nd cones
1
Cast iron
iston
1
*% M O
/edia "emperature
1
!ir
1
F)OF C
ressure ;ange
1
O %mP
./.2 F&o4 co'tro& a&$" T"c9'#ca& Data 41
ort si0e
1
F.?E 5 =F >P m
ressure
1
F)O 5 =F %mP
/edia
1
!ir
]uantity
1
=
./.3 Co''"ctors T"c9'#ca& %ata
/a5 -or3ing pressure
1
=F 5 =F %mP
"emperature
1
F)=FF C
luid media
1
!ir
/aterial
1
./.( Hos"s T"c9'#ca& %at"
/a5 pressure
1
$uter diameter
=F 5 =F %mP 1
Inner diameter
1
42
? mm A ? 5 =F m
E. mm A E. 5 =F m
;. 6ORIN) PRINCIPLE
4ince pneumatic circuit plays a vital role in this device, it is very necessary to e5plain the -or3ing of this circuit. Initially starting -ith air compresses, its function is to compress air from a lo- inlet pressure (usually atmospheric+ to a higher pressure level. "his is an accomplished by reducing the volume of the air. !ir compressors are generally positive displacement units and are either of the reciprocating piston type or the rotary screor rotary vane types. "he air compressor used here is a typically small si0ed, t-o)stage compressor unit.
It also consists of a
compressed air tan3, electric rotor and pulley drive, pressure controls and instruments for 8uic3 hoo3 up and use.
"he
compressor is driver by a = H motor and designed to operate in =F M =FF 4I range.
If the pressure e5ceeds the designed
pressure of the receiver a release value provided releases the e5cesses air and thus stays a head of any ha0ards to ta3e place. "hen having a pressure regulator -here the desired pressure to the operated is set.
Here a variable pressure regulator is
adopted. "hrough a variety of direction control value are available, a hand operated spool value -ith detent is applied. "he spool value used here is ports, E positions. "here are t-o e5haust ports, t-o outlet ports and one inlet port.
In t-o
e5treme positions only the directions can be changed -hile the 43
Centro ore is a neutral position and no physical changes are incurred. "he @ outlet ports are connected to an actuator (Cylinder+. "he pneumatic activates is a double acting, single rod cylinder. "he cylinder output is coupled to further purpose. "he piston end has an air horning eGect to prevent sudden thrust at e5treme ends. ;.1 PRINCIPLES OF 6ORIN) "he
compressed air from the compressor reaches the
direction control valve. "he direction control valve changes the direction of o- according to the valve position handle. "he
compressed air pass through the direction control valve
and it is admitted into the front end of the cylinder bloc3. "he air pushes the piston for the lifting stro3e. !t the end of the lifting stro3e air from the valve reaches the rear end of the cylinder bloc3. "he pressure remains the same but the area is less due to the presence of piston rod. "his e5erts greater pressure on the piston, pushing it at a faster rate thus enabling faster return stro3e. "he
stro3e length of the piston can be changed by ma3ing
suitable adjustment in the hand liver valve operating position.
44
ADANTA)ES? DISADANTA)ES AND APPLICATIONS <.1 ADANTA)ES:B
It re8uires simple maintenance cares
Chec3ing and cleaning are easy, because of the main parts are scre-ed.
Handling is easy.
/anual po-er not re8uired
;epairing is easy.
;eplacement of parts is easy.
<.2 DISADANTA)ES
Initial cost is high.
4eparate air tan3 or compressor is re8uired.
<.3 APPLICATIONS
!ll hydraulic and pneumatic dipper applications.
*asy to unload the materials
45
CHAPTERB1
1. LIST OF MATERIALS
S&. No. i. ii.
PARTS
neumatic ;eciprocating Cylinder @ Jirection Control Valve
,t-.
Mat"r#a&
= =
/.4 !luminiu m
iii. iv. v. vi.
neumatic "ube Hose Collar and ;educer 4tand (rame+ lo- control valve
4%
) ) = =
CHAPTERB11 11. COST ESTIMATION 11.1
MATERIAL COST:
S&. No. i. ii.
v.
PARTS
,t-.
Mat"r#a&
Aou't Rs
neumatic Cylinder @ Jirection Control
= =
/.4 !luminium
Valve
iber
and
) )
= = = =
/ild steel lastic !luminum Lead)!cid
-ith
vi. vii.
Cap neumatic "ube Hose Collar
Viii I5 i
;educer 4tand (rame+ Jash ad J.C /otor lo- control valve TOTAL
4(
CHAPTERB12
12. CONCLUSION
"his project -or3 has provided us an e5cellent opportunity and e5perience, to use our limited 3no-ledge. 9e gained a lot of practical 3no-ledge regarding, planning, purchasing, assembling and machining -hile doing this project -or3. 9e feel that the project -or3 is a good solution to bridge the gates bet-een institution and industries. 9e are proud that -e have completed the -or3 -ith the limited time successfully. "he “THREE AXIS PNEUMATIC MODERN TIPPER7 is -or3ing -ith satisfactory conditions. 9e
are able to understand the di2culties in maintaining the tolerances and also 8uality. 9e have done to our ability and s3ill ma3ing ma5imum use of available facilities. In conclusion remar3s of our project -or3, let us add a fe- more lines about our impression project -or3. "hus -e have developed a “THREE AXIS PNEUMATIC MODERN TIPPER -hich helps to 3no- ho- to achieve lo- cost ”
automation. "he operating procedure of this system is very 4+
simple, so any person can operate.
8I8LIO)RAPH5
=.
7.<.4.
%arang, “Autoob#&" E'+#'""r#'+”, `hanna
ublishers, Jelhi, =>>=, pp ?D=. @.
9illiam H. Cro-se, “Autoob#&" E'+#'""r#'+”.
E.
/*CH!%I4/4 I% /$J*;% *%7I%**;I%7 J*4I7% Vol.
!;" I . *L*/*%"4 $ 9$;`4H$ "*CH%$L$7R M V$L II )4.`. H!;! CH$\JH\;R )4.`. <$4* )!.`. H!;! CH$\JH*;R .
4";*%7"H $ /!"*;I!L4 4)
)I.<. ;!4!J
V.
