ANNA UNIVERSITY : CHENNAI 600 025
Certified that this project report “Alternate transmission
system” is the bonafide work of “ Rohith Kumar.M (111711114123),
Rajkiran.V (111711114117),Sasidaran.K (111711114129), Sathya
Lenin.E.A.R.C (111711114130)” carried out the project word under my
Prof. Dr. K. R. SENTHIL KUMAR, M.E, Ph.D. Mr.D.Jayabalan, M.E.,
HEAD OF THE DEPARTMENT SUPERVISOR
Department of Mechanical Engg, Department of Mechanical Engg,
R.M.K. Engineering College, R.M.K. Engineering College,
Kavaraipettai, Chennai-601206. Kavaraipettai, Chennai-601206.
Submitted for the project viva voce held on ………. at R.M.K.
Engineering College, Kavaraipettai, Chennai-601 206.
We would express our gratitude to our beloved chairman
SHRI R. S. MUNIRATHINAM, R.M.K. Engineering College,
Kavaraipettai, Chennai – 601206 for having arranged to do this
We express our sincere thanks to our beloved guide
Mr.D.Jayabalan, M.E., (PhD), for his valuable guidance and
encouragement for finishing the project successfully.
We would also like to express our sincere thanks to our
beloved Principal Dr. ELWIN CHANDRA MONIE and Head
of the Department Prof. Dr. K. R. SENTHIL KUMAR, for
having made for guidance and counseling throughout this
The main objective of our work “Alternate transmission
system “is to design a chain drive which can rotate under
different axis .In a conventional chain drive system, when
the driven’s angle is changed ,the drive’s angle must be
changed correspondingly to achieve smooth transmission
In our project “Design and analysis of alternate
transmission system” we overcome this disability by
achieving transmission even when the driven’s angle is
This has a wide range of application were machine
containing multi drives can be replaced with single drive.
In this design we use a conical tooth which slides and
locks automatically when the driven’s axis is changed.
Each chain section consists of a hub connected to another
hub with two pins on one side and with teeth section on
the other side. In this project we use two software, one for
designing and drafting and another for analysis.
TABLE OF CONTENTS
CHAPTER NO. TITLE PAGE NO.
1.INTRODUCTION 1 COMPONENTS
2.2. ADVANTAGES AND DISADVANTAGES 2.3.USES 3 2.3.1.Engine starters 3 2.3.2.Bicycle 2.3.3.Helicopters 2.3.4.History 3.PIN 1 3.1.HISTORY 3.2.COMMON DESIGNS 3.2.1.Angular Contact 3.2.2.Axial 3.2.3.Deep-groove 3.3.LUBRICATION 3.4.APPLICATION 4.PIN2 4.1.APPLICATION 4.2.HISTORY
5.1.TRANSPORATION 5.2.TRACKED VEHICLES 5.3.FILM AND PAPER
6.2.CHAINS VERSUS BELTS 6.3.USE IN VEHICLES
220.127.116.11.Transmitting power to wheels
8.DESIGNING 8.1.DESCRIPTION 8.2.COMMUTATION 8.3.EXCITATION 8.4.MODERN USES 9. ANALYSIS 9.1.PROCESSES 9.1.1.ARC 9.1.2.POWER SUPPLIES
10.1.1.1.Tapered Turning 10.1.1.2.Spherical Generation 10.1.1.3.Hard Turning
11.DESIGN AND FABRICATION 12.WORKING
13.ADVANTAGES AND DISADVANTAGES 14.SPECIFICATION AND CALCULATION 15.COST ANALYSIS
The Introduction of our work “Dynamo Street Lamps” includes,
Dynamo Street lamps consists of components such as Flywheel,Freewheel,Ballbearings,Gear sprockets,Chain drives,Dynamo,casings,wood plate,steel plates,sprockets,springs which compress.when the Rack directions which makes the freewheel to rotate in positive directions which makes shaft also to rotate in positive direction which tends the sprockets to rotate and also makes Dynamo to produce current which can be measured by ammeter.
Ratcheting freewheel mechanism (van Anden, 1869)
In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is mistakenly called a freewheel, but is otherwise unrelated.`
The condition of a driven shaft spinning faster than its driveshaft exists in
An analogous condition exists in an automobile with a manual transmission going down hill or any situation where the driver takes his or her foot off the gaspedal, closing the throttle; the wheels want to drive the engine, possibly at a higher RPM. In a two-strokeengine this can be a catastrophic situation: as many two stroke engines depend on a fuel/oil mixture for lubrication, a shortage of fuel to the engine would result in a shortage of oil in the cylinders, and the pistons would seize after a very short time causing extensive engine damage. Saab used a freewheel system in their two-stroke models for this reason and maintained it in the Saab 96 V4 and early Saab 99 for better fuel efficiency.
The simplest freewheel device consists of two saw-toothed, spring-loaded discs pressing against each other with the toothed sides together, somewhat like a ratchet. Rotating in one direction, the saw teeth of the drive disc lock with the teeth of the driven disc, making it rotate at the same speed. If the drive disc slows down or stops rotating, the teeth of the driven disc slip over the drive disc teeth and continue rotating, producing a characteristic clicking sound proportionate to the speed difference of the driven gear relative to that of the (slower) driving gear.
A more sophisticated and rugged design has spring-loaded steel rollers inside a driven cylinder. Rotating in one direction, the rollers lock with the cylinder making it rotate in unison. Rotating slower, or in the other direction, the steel rollers just slip inside the cylinder.
Most bicycle freewheels use an internally step-toothed drum with two or more spring-loaded, hardened steel pawls to transmit the load. More pawls help spread the wear and give greater reliability although, unless the device is made to tolerances not normally found in bicycle components, simultaneous engagement of more than two pawls is rarely achieved.
2.2Advantages and disadvantages
clutch pedal, limiting the use of the manual clutch to starting from standstill or stopping. The Saab freewheel can be engaged or disengaged by the driver by respectively pushing or pulling a lever. This will lock or unlock the main shaft with the freewheel hub. A freewheel also produces slightly better fuel economy on carbureted engines (without fuel turn-off on engine brake) and less wear on the manual clutch, but leads to more wear on the brakes as there is no longer any ability to perform engine braking. This may make freewheel transmissions dangerous for use on trucks and automobiles driven in mountainous regions, as prolonged and continuous application of brakes to limit vehicle speed soon leads to brake-system overheating followed shortly by total failure.
A freewheel assembly is also widely used on engine starters as a kind of protective device. Starter motors usually need to spin at 3,000 RPM to get the engine to turn over. When the key is held in the start position for any amount of time after the engine has started, the starter cannot spin fast enough to keep up with the flywheel. Because of the extreme gear ratio between starter gear and flywheel (about 15 or 20:1) it would spin the starter armature at dangerously high speeds, causing an explosion when the centripetal force acting on the copper coils wound in the armature can no longer resist the outward force acting on them. In starters without the freewheel or overrun clutch this would be a major problem because, with the flywheel spinning at about 1,000 RPM at idle, the starter, if engaged with the flywheel, would be forced to spin between 15,000 and 20,000 RPM. Once the engine has turned over and is running, the overrun clutch will release the starter from the flywheel and prevent the gears from re-meshing (as in an accidental turning of the ignition key) while the engine is running. A freewheel clutch is now used in many motorcycles with an electric starter motor. It is used as a
replacement for the Bendix drive used on most auto starters because it reduces the electrical needs of the starting system.
In the older style of bicycle, where the free wheel mechanism is included in the gear assembly, the system is called a free wheel, whereas the newer style, in which the
Freewheels are also used in rotorcraft. As a bicycle's wheels need to be able to rotate faster than the pedals, so do a rotorcraft's blades need to be able to spin faster than its drive engines. This is especially important in the event of an engine failure where a free wheel in the main transmission allows the main and tail rotor systems to continue to spin independent of the drive system. This provides for continued flight control and an autorotation landing.
In 1869, William Van Anden invented the freewheel for the bicycle. His design placed a ratchet device in the hub of the front wheel, which allowed the rider to propel himself forward without pedaling constantly. Initially, bicycle enthusiasts rejected the idea of a free wheel because they believed it would complicate the mechanical functions of the bicycle. Bicycle enthusiasts believed that the bicycle was supposed to remain as simple as possible without any additional mechanisms, such as the free wheel.
Due to the lack of popularity for the free wheel, it was not continuously re-engineered to be more useful for several decades. In 1899, American manufacturers developed the “coaster brake,” which allowed riders to brake by pedaling backwards and included the freewheel mechanism. At the turn of the century, bicycle manufacturers within Europe and America included the free wheel mechanism in a majority of their bicycles but now the freewheel was incorporated in the rear sprocket of a bicycle unlike Van Anden’s initial design.
In 1924, the French bicycle company, Le Cyclo, introduced a gear-shifting bicycle with a two sprocket freewheel, which would allow riders to go uphill with more ease. In the late 1920s, Le Cyclo began using both front and rear derailleurs in combination with a double chain ring giving the bicycle twice as many gears. In the early 1930s, Le Cyclo invented a four sprocket freewheel and several years later the company combined the four sprocket freewheel with a triple chain ring giving the bicycle twelve gears.
In the 1970s, Japanese manufacturers introduced their own version of the derailleurs. The Japanese bicycle company, SunTour introduced the slant parallelogram derailleurs which were tilted back allowing the cage to be located farther away from the freewheel than the European version. This allowed for the chain to shift more smoothly from gear to gear. The Japanese version of the derailleur became the standard and still is today.
Working principle for a ball bearing
A 4 point angular contact ball bearing
Wingquist's and SKF's self-aligning ball bearing
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearingraces.
The purpose of a ball bearing is to reduce rotational friction and
support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. In most applications, one race is
stationary and the other is attached to the rotating assembly (e.g., a hub or shaft). As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were sliding against each other.
Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races.
However, they can tolerate some misalignment of the inner and outer races.
Although roller bearings had been developed since ancient times, the first modern recorded patent on ball bearings was awarded to Philip Vaughan, a Welsh inventor and ironmaster who created the first design for a ball bearing in Carmarthen in 1794. His was the first modern ball-bearing design, with the ball running along a groove in the axle assembly.
Jules Suriray, a Parisian bicycle mechanic, designed the first radial style ball bearing in 1869, which was then fitted to the winning bicycle ridden by James Moore in the world's first bicycle road race, Paris-Rouen, in November 1869.
There are several common designs of ball bearing, each offering various trade-offs. They can be made from many different materials, including: stainless steel, chrome steel, and ceramic (silicon nitride (Si3N4)). A hybrid ball bearing is a bearing with ceramic
balls and races of metal.
An angular contact ball bearing uses axially asymmetric races. An axial load passes in a straight line through the bearing, whereas a radial load takes an oblique path that tends to want to separate the races axially. So the angle of contact on the inner race is the same as that on the outer race. Angular contact bearings better support "combined loads" (loading in both the radial and axial directions) and the contact angle of the bearing should be matched to the relative proportions of each. The larger the contact angle (typically in the range 10 to 45 degrees), the higher the axial load supported, but the lower the radial load. In high speed applications, such as turbines, jet engines, and dentistry equipment, the centrifugal forces generated by the balls changes the contact angle at the inner and outer race. Ceramics such as silicon nitride are now regularly used in such applications due to their low density (40% of steel). These materials significantly reduce centrifugal force and function well in high temperature
environments. They also tend to wear in a similar way to bearing steel—rather than cracking or shattering like glass or porcelain.
Most bicycles use angular-contact bearings in the headsets because the forces on these bearings are in both the radial and axial direction.
An axial ball bearing uses side-by-side races. An axial load is transmitted directly through the bearing, while a radial load is poorly supported and tends to separate the races,so that a larger radial load is likely to damage the bearing.
In a deep-groove radial bearing, the race dimensions are close to the dimensions of the balls that run in it. Deep-groove bearings can support higher loads.
For a bearing to operate properly, it needs to be lubricated. In most cases the lubricant is based on elastohydrodynamic effect (by oil or grease) but working at extreme
temperatures dry lubricated bearings are also available.
For a bearing to have its nominal lifespan at its nominal maximum load, it must be lubricated with a lubricant (oil or grease) that has at least the minimum dynamic viscosity (usually denoted with the Greek letter ) recommended for that bearing. The recommended dynamic viscosity is inversely proportional to diameter of bearing. The recommended dynamic viscosity decreases with rotating frequency. As a rough indication: for less than 3000 RPM, recommended viscosity increases with factor 6 for a factor 10 decrease in speed, and for more than 3000 RPM, recommended viscosity decreases with factor 3 for a factor 10 increase in speed.
For a bearing where average of outer diameter of bearing and diameter of axle hole is 50 mm, and that is rotating at 3000 RPM, recommended dynamic viscosity is 12 mm²/s.
Note that dynamic viscosity of oil varies strongly with temperature: a temperature increase of 50–70 °C causes the viscosity to decrease by factor 10.
If the viscosity of lubricant is higher than recommended, lifespan of bearing increases, roughly proportional to square root of viscosity. If the viscosity of the lubricant is lower than recommended, the lifespan of the bearing decreases, and by how much depends on which type of oil being used. For oils with EP ('extreme pressure') additives, the lifespan is proportional to the square root of dynamic viscosity, just as it was for too high viscosity, while for ordinary oil's lifespan is proportional to the square of the viscosity if a lower-than-recommended viscosity is used.
Lubrication can be done with a grease, which has advantages that grease is normally held within the bearing releasing the lubricant oil as it is compressed by the balls. It provides a protective barrier for the bearing metal from the environment, but has disadvantages that this grease must be replaced periodically, and maximum load of bearing decreases (because if bearing gets too warm, grease melts and runs out of bearing). Time between grease replacements decreases very strongly with diameter of bearing: for a 40 mm bearing, grease should be replaced every 5000 working hours, while for a 100 mm bearing it should be replaced every 500 working hours.
Lubrication can also be done with an oil, which has advantage of higher maximum load, but needs some way to keep oil in bearing, as it normally tends to run out of it. For oil lubrication it is recommended that for applications where oil does not become warmer than 50 °C, oil should be replaced once a year, while for applications where oil does not become warmer than 100 °C, oil should be replaced 4 times per year. For car engines, oil becomes 100 °C but the engine has an oil filter to continually improve oil quality; therefore, the oil is usually changed less frequently than the oil in bearings.
In general, ball bearings are used in most applications that involve moving parts. Some of these applications have specific features and requirements:
Hard drive bearings used to be highly spherical, and were said to be the best spherical manufactured shapes, but this is no longer true, and more and more are being replaced with fluid bearings.
German ball bearing factories were often a target of allied aerial bombings during World War II; such was the importance of the ball bearing to the German war
In horology, the company Jean Lassale designed a watch movement that used ball bearings to reduce the thickness of the movement. Using 0.20 mm balls, the Calibre 1200 was only 1.2 mm thick, which still is the thinnest mechanical watch movement.
Aerospace bearings are used in many applications on commercial, private and military aircraft including pulleys, gearboxes and jet engine shafts. Materials include M50 tool steel (AMS6491), Carbon chrome steel (AMS6444), the corrosion resistant AMS5930, 440C stainless steel, silicon nitride (ceramic) and titanium carbide-coated 440C.
Skateboard wheels each contain two bearings, which are subject to both axial and radial time-varying loads. Most commonly bearing 608-2Z is used (a deep groove ball bearing from series 60 with 8 mm bore diameter)
An industrial flywheel.
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertiaand thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed. Energy is transferred to a flywheel by applying torque to it, thereby increasing its rotational speed, and hence its stored energy. Conversely, a flywheel releases stored energy by applying torque to a mechanical load, thereby decreasing its rotational speed.
Common uses of a flywheel include:
Providing continuous energy when the energy source is discontinuous. For example, flywheels are used in reciprocating enginesbecause the energy source, torque from the engine, is intermittent.
Delivering energy at rates beyond the ability of a continuous energy source. This is achieved by collecting energy in the flywheel over time and then releasing the energy quickly, at rates that exceed the abilities of the energy source.
Controlling the orientation of a mechanical system. In such applications, the angular momentum of a flywheel is purposely transferred to a load when energy is transferred to or from the flywheel.
Flywheels are typically made of steel and rotate on conventional bearings; these are generally limited to a revolution rate of a few thousand RPM. Some modern flywheels are made of carbon fiber materials and employ magnetic bearings, enabling them to revolve at speeds up to 60,000 RPM.
Carbon-composite flywheel batteries have recently been manufactured and are proving to be viable in real-world tests on mainstream cars. Additionally, they are more eco-friendly, as it is not necessary to take special measures in the disposal of them.
A Landini tractor with exposed flywheel.
Flywheels are often used to provide continuous energy in systems where the energy source is not continuous. In such cases, the flywheel stores energy when torque is applied by the energy source, and it r eleases stored energy when the energy source is not applying torque to it. For example, a flywheel is used to maintain constant angular velocity of the crankshaft in a reciprocating engine. In this case, the flywheel—which is mounted on the crankshaft—stores energy when torque is exerted on it by a
torque on it. Other examples of this are friction motors, which use flywheel energy to power devices such as toy cars.
Modern automobile engine flywheel
A flywheel may also be used to supply intermittent pulses of energy at transfer rates that exceed the abilities of its energy source, or when such pulses would disrupt the energy supply (e.g., public electric network). This is achieved by accumulating stored energy in the flywheel over a period of time, at a rate that is compatible with the energy source, and then releasing that energy at a much higher rate over a relatively short time. For example, flywheels are used in riveting machines to store energy from the motor and release it during the riveting operation.
The phenomenon of precession has to be considered when using flywheels in vehicles. A rotating flywheel responds to any momentum that tends to change the direction of its axis of rotation by a resulting precession rotation. A vehicle with a vertical-axis flywheel would experience a lateral momentum when passing the top of a hill or the bottom of a valley (roll momentum in response to a pitch change). Two counter-rotating flywheels may be needed to eliminate this effect. This effect is leveraged in reaction wheels, a typ e of flywheel employed in satellites in which the flywheel is used to orient the satellite's instruments without thruster rockets.
The principle of the flywheel is found in the Neolithic spindle and the potter's wheel. The flywheel as a general mechanical device for equalizing the speed of rotation is, according to the American medievalist Lynn White, recorded in the De diversibus
In the Industrial Revolution, James Watt contributed to the development of the flywheel in the steam engine, and his contemporaryJames Pickard used a flywheel combined with a crank to transform reciprocating into rotary motion.
A flywheel with variable moment of inertia, conceived by Leonardo da Vinci.
A flywheel is a spinning wheel or disc with a fixed axle so that rotation is only about one axis. Energy is stored in the rotor as kinetic energy, or more specifically, rotational energy:
ω is the angular velocity, and
is the moment of inertia of the mass about the center of rotation. The moment of inertia is the measure of resistance to torqueapplied on a spinning object (i.e. the higher the moment of inertia, the slower it will spin when a given force is applied).
The moment of inertia for a solid cylinder is ,
When calculating with SI units, the standards would be for mass, kilograms; for radius, meters; and for angular velocity, radians per second. The resulting answer would be injoules.
The amount of energy that can safely be stored in the rotor depends on the point at which the rotor will warp or shatter. The hoop stress on the rotor is a major
consideration in the design of a flywheel energy storage system.
is the tensile stress on the rim of the cylinder
is the density of the cylinder
is the radius of the cylinder, and
is the angular velocity of the cylinder.
This formula can also be simplified using specific tensile strength and tangent velocity:
is the specific tensile strength of the material
is the tangent velocity of the rim.
Table of energy storage traits
Flywheel purpose, type Geometric shape factor (k) (unitless – varies with shape) Mas s (kg) Diamete r (cm) Angular velocity (rpm) Energy stored (MJ) Energy stored (kWh) Small battery 0.5 100 60 20,000 9.8 2.7
braking in trains 0.5 3000 50 8,000 33.0 9.1
backup 0.5 600 50 30,000 92.0 26.0
A rimmed flywheel has a rim, a hub, and spokes. The structure of a rimmed flywheel is complex and, consequently, it may be difficult to compute its exact moment of inertia] A
rimmed flywheel can be more easily analysed by applying various simplifications. For example:
Assume the spokes, shaft and hub have zero moments of inertia, and the flywheel's moment of inertia is from the rim alone.
The lumped moments of inertia of spokes, hub and shaft may be estimated as a percentage of the flywheel's moment of inertia, with the remainder from the rim, so that
For example, if the moments of inertia of hub, spokes and shaft are deemed negligible, and the rim's thickness is very small compared to its mean radius ( ), the radius of rotation of the rim is equal to its mean radius and thus:
16 tooth sprocket. Do = Sprocket diameter. Dp = Pitch diameter
A sprocket and roller chain
A sprocket or sprocket-wheel is a profiled wheel with teeth, cogs, or even
sprockets that mesh with a chain,track or other perforated or indented material. The name "sprocket" applies generally to any wheel upon which are radial projections that engage a chain passing over it. It is distinguished from a gear in that sprockets are never meshed together directly, and differs from a pulley in that sprockets have teeth and pulleys are smooth.
Sprockets are used in bicycles, motorcycles, cars, tracked vehicles, and
other machinery either to transmit rotary motion between two shafts where gears are unsuitable or to impart linear motion to a track, tape etc. Perhaps the most common form of sprocket may be found in the bicycle, in which the pedal shaft carries a large sprocket-wheel, which drives a chain, which, in turn, drives a small sprocket on the axle of the rear wheel. Early automobiles were also largely driven by sprocket and chain mechanism, a practice largely copied from bicycles.
Sprockets are of various designs, a maximum of efficiency being claimed for each by its originator. Sprockets typically do not have a flange. Some sprockets used with timing belts have flanges to keep the timing belt centered. Sprockets and chains are also used for power transmission from one shaft to another where slippage is not admissible, sprocket chains being used instead of belts or ropes and sprocket-wheels instead of pulleys. They can be run at high speed and some forms of chain are so constructed as to be noiseless even at high speed.
In the case of bicycle chains, it is possible to modify the overall gear ratio of the chain drive by varying the diameter (and therefore, the tooth count) of the sprockets on each side of the chain. This is the basis of derailleur gears. A multi-speed bicycle, by
providing two or three different-sized driving sprockets and up to 11 (as of 2014)
different-sized driven sprockets, allows up to 30 different gear ratios. The resulting lower gear ratios make the bike easier to pedal up hills while the higher gear ratios make the bike more powerful to pedal on flats and downhills. In a similar way, manually changing the sprockets on a motorcycle can change the characteristics of acceleration and top speed by modifying the final drive gear ratio.
Tread drive sprocket of the Leclerc main battle tank (2006).
In the case of vehicles with caterpillar tracks the engine-driven toothed-wheel
transmitting motion to the tracks is known as the drive sprocket and may be positioned at the front or back of the vehicle, or in some cases both. There may also be a third sprocket, elevated, driving the track.
5.3Film and paper
Moving picture mechanism from 1914. The sprocket wheels a, b, and c engage and transport the film. a and b move with uniform velocity and c indexes each frame of the film into place for projection.
Sprockets are used in the film transport mechanisms of movie projectors and movie cameras. In this case, the sprocket wheels engage film perforations in the film stock. Sprocket feed was also used for punched tape and is used for paperfeed to
Roller chain andsprocket
Mack AC delivery truck at the Petersen Automotive Museum with chain drive visible
Chain drive is a way of transmitting mechanical power from one place to another. It is
often used to convey power to the wheels of a vehicle,
particularly bicycles and motorcycles. It is also used in a wide variety of machines besides vehicles.
Most often, the power is conveyed by a roller chain, known as the drive
chain or transmission chain, passing over a sprocket gear, with the teeth of the gear meshing with the holes in the links of the chain. The gear is turned, and this pulls the chain putting mechanical force into the system. Another type of drive chain is the Morse chain, invented by the Morse Chain Company of Ithaca, New York, USA. This has inverted teeth.
Sometimes the power is output by simply rotating the chain, which can be used to lift or drag objects. In other situations, a second gear is placed and the power is recovered by attaching shafts or hubs to this gear. Though drive chains are often simple oval loops,
wheels. By varying the diameter of the input and output gears with respect to each other, the gear ratio can be altered, so that, for example, the pedals of a bicycle can spin all the way around more than once for every rotation of the gear that drives the wheels.
Oldest known illustration of an endless power-transmitting chain drive, from Su Song's book of 1092 describing his clock tower ofKaifeng
Sketch of roller chain by Leonardo da Vinci
The oldest known application of a chain drive appears in the Polybolos, a repeating crossbow desc
ribed by the Greek engineer Philon of Byzantium (3rd century BC). Two flat-linked chains were connected to a windlass, which by winding back and forth would automatically fire the machine's arrows until its magazine was empty. Although the device did not transmit power continuously since the chains "did not transmit power from shaft to shaft", the Greek design marks the beginning of the history of the chain drive since "no earlier instance of such a cam is known, and none as complex is known until the 16th century. It is here that the flat-link chain, often attributed to Leonardo da Vinci, actually made its first appearance."
The first continuous power-transmitting chain drive was depicted in the
written horological treatise of the Song Dynasty (960–1279) Chineseengineer Su Song (1020-1101 AD), who used it to operate the armillary sphere of
his astronomicalclock tower as well as the clock jack figurines presenting the time of day by mechanically banging gongs and drums. The chain drive itself was given power via the hydraulic works of Su's water clock tank and waterwheel, the latter which acted as a large gear.
6.2Chains versus belts
Roller chain and sprockets is a very efficient method of power transmission compared to belts, with far less frictional loss.
Although chains can be made stronger than belts, their greater mass increases drive train inertia.
Drive chains are most often made of metal, while belts are often rubber, plastic, or other substances. Drive belts can slip unless they have teeth, which means that the output side may not rotate at a precise speed, and some work gets lost to the friction of the belt against its rollers. Teeth on toothed drive belts generally wear faster than links on
chains, but wear on rubber or plastic belts and their teeth is often easier to observe. Conventional roller chain drives suffer the potential for vibration, as the effective radius of action in a chain and sprocket combination constantly changes during revolution ("Chordal action"). If the chain moves at constant speed, then the shafts must
accelerate and decelerate constantly. If one sprocket rotates at a constant speed, then the chain (and probably all other sprockets that it drives) must accelerate and
decelerate constantly. This is usually not an issue with many drive systems, however most motorcycles are fitted with a rubber bushed rear wheel hub to virtually eliminate this vibration issue. Toothed belt drives are designed to avoid this issue by operating at a constant pitch radius.
Chains are often narrower than belts, and this can make it easier to shift them to larger or smaller gears in order to vary the gear ratio. Multi-speed bicycles
withderailleurs make use of this. Also, the more positive meshing of a chain can make it easier to build gears that can increase or shrink in diameter, again altering the gear ratio.
example the rollers that drive conveyor belts are themselves often driven by drive chains.
Drive shafts are another common method used to move mechanical power around that is sometimes evaluated in comparison to chain drive; in particular belt drive vs chain drive vs shaft drive is a key design decision for most motorcycles. Drive shafts tend to be tougher and more reliable than chain drive, but the bevel gears have far more friction than a chain. For this reason virtually all high performance motorcycles use chain drive, with shaft driven arrangements generally used for non-sporting machines. Toothed belt drives are used for some (non-sporting) models.
6.3Use in vehicles 6.3.1Bicycles
Chain drive was the main feature which differentiated the safety bicycle introduced in 1885, with its two equal-sized wheels, from the direct-drivepenny-farthing or "high wheeler" type of bicycle. The popularity of the chain-driven safety bicycle brought about the demise of the penny-farthing, and is still a basic feature of bicycle design today.
18.104.22.168Transmitting power to the wheels
Chain final drive, 1912 illustration
Chain drive was a popular power transmission system from the earliest days of
the automobile. It gained prominence as an alternative to the Système Panhard with its rigid Hotchkissdriveshaft and universal joints.
A chain-drive system uses one or more roller chains to transmit power from a differential to the rear axle. This system allowed for a great deal of vertical axle movement (for example, over bumps), and was simpler to design and build than a rigid driveshaft in a workable suspension. Also, it had less unsprung weight at the rear
wheels than the Hotchkiss drive, which would have had the weight of the driveshaft and differential to carry as well. This meant that the vehicle would have a smoother ride. The lighter unsprung mass would allow the suspension to react to bumps more effectively. Frazer Nash were strong proponents of this system using one chain per gear selected by dog clutches. The Frazer Nash chain drive system, (designed for the GN Cyclecar Company by Archibald Frazer-Nash and Henry Ronald Godfrey) was very effective, allowing extremely fast gear selections. The Frazer Nash (or GN) transmission system provided the basis for many "special" racing cars of the 1920s and 1930s, the most famous being Basil Davenport's Spider which held the outright record at the Shelsley Walsh Speed Hill Climb in the 1920s.
Parry-Thomas was killed during a land speed record attempt in his car 'Babs' when the chain final-drive broke, decapitating him.
A compression coil spring
A tension coil spring
A coil spring, also known as a helical spring, is a mechanical device, which is typically used to store energy due to resilience and subsequently release it, to absorb shock, or to maintain a force between contacting surfaces. They are made of an elastic material formed into the shape of a helix which returns to its natural length when unloaded. One type of coil spring is a torsion spring: the material of the spring acts in torsion when the spring is compressed or extended. The quality of spring is judged from the energy it can absorb. the spring which is capable of absorbing the greatest amount of energy for the given stress is the best one. Metal coil springs are made by winding a wire around a shaped former - a cylinder is used to form cylindrical coil springs.
Types of coil spring are:
Tension/extension coil springs, designed to resist stretching. They usually have a hook or eye form at each end for attachment.
Compression coil springs, designed to resist being compressed. A typical use for compression coil springs is in car suspension systems.
Torsion springs, designed to resist twisting actions. Often associated to clothes pegs or up-and-over garage doors.
"Dynamo Electric Machine" (end view, partly section, U.S. Patent 284,110)
A dynamo is an electrical generator that produces direct current with the use of
acommutator. Dynamos were the first electrical generators capable of delivering power for industry, and the foundation upon which many other later electric-power conversion
devices were based, including the electric motor, the alternating-currentalternator, and
the rotary converter. Today, the simpler alternator dominates large scale power
generation, for efficiency, reliability and cost reasons. A dynamo has the disadvantages of a mechanical commutator. Also, converting alternating to direct current using power
rectification devices (vacuum tube or more recently solid state) is effective and usually
The word dynamo (from the Greek word dynamis; meaning power) was originally
another name for an electrical generator, and still has some regional usage as a
replacement for the word generator. A small electrical generator built into the hub of a
bicycle wheel to power lights is called a hub dynamo, although these are invariably AC
devices] and are actually magnetos.
The dynamo uses rotating coils of wire and magnetic fields to convert mechanical
rotation into a pulsing direct electriccurrent through Faraday's law of induction. A
within that field. The motion of the wire within the magnetic field causes the field to push on the electrons in the metal, creating an electric current in the wire. On small machines
the constant magnetic field may be provided by one or more permanent magnets; larger
machines have the constant magnetic field provided by one or more electromagnets,
which are usually called field coils.
The commutator is needed to produce direct current. When a loop of wire rotates in a
magnetic field, the potential induced in it reverses with each half turn, generating an
alternating current. However, in the early days of electric experimentation,alternating
current generally had no known use. The few uses for electricity, such as electroplating,
used direct current provided by messy liquid batteries. Dynamos were invented as a
replacement for batteries. The commutator is essentially a rotary switch. It consists of a
set of contacts mounted on the machine's shaft, combined with graphite-block stationary contacts, called "brushes", because the earliest such fixed contacts were metal brushes. The commutator reverses the connection of the windings to the external circuit when the potential reverses, so instead of alternating current, a pulsing direct current is produced.
The earliest dynamos used permanent magnets to create the magnetic field. These
were referred to as "magneto-electric machines" or magnetos. However, researchers
found that stronger magnetic fields, and so more power, could be produced by
using electromagnets (field coils) on the stator. These were called "dynamo-electric
machines" or dynamos. The field coils of the stator were originally separately excited by a separate, smaller, dynamo or magneto. An important development
by Wilde and Siemens was the discovery that a dynamo could also bootstrap itself to be self-excited, using current generated by the dynamo itself. This allowed the growth of a much more powerful field, thus far greater output power.
Dynamos still have some uses in low power applications, particularly where low
voltage DC is required, since an alternatorwith a semiconductorrectifier can be
inefficient in these applications. Hand cranked dynamos are used in clockwork
Gas metal arc welding (MIG welding)
Welding is a fabrication or sculpturalprocess that joins materials,
usually metals or thermoplastics, by causingcoalescence. This is often done
by melting the workpieces and adding a filler material to form a pool of molten material (the weld pool) that cools to become a strong joint, with pressure sometimes used in conjunction with heat, or by itself, to produce the weld. This is in contrast
with soldering and brazing, which involve melting a lower-melting-point material
between the workpieces to form a bond between them, without melting the work pieces. There are several different ways to weld, such as: Shielded Metal Arc Welding, Gas Tungsten Arc Welding, Tungsten Inert Gas and Metallic Inert Gas. MIG or Metallic Inert Gas involves a wire fed "gun" that feeds wire at an adjustable speed and sprays a shielding gas (generally pure Argon or a mix of Argon and CO2) over the weld puddle to protect it from the outside world. TIG or Tungsten Inert Gas involves a much smaller hand-held gun that has a tungsten rod inside of it. With most, you use a pedal to adjust your amount of heat and hold a filler metal with your other hand and slowly feed it. Stick welding or Shielded Metal Arc Welding has an electrode that has flux, the protectant for
Slag protects the weld puddle from the outside world. Flux-Core is almost identical to stick welding except once again you have a wire feeding gun, the wire has a thin flux coating around it that protects the weld puddle.
Many different energy sources can be used for welding, including a gas flame, an electric arc, a laser, an electron beam,friction, and ultrasound. While often an
industrial process, welding may be performed in many different environments, including open air, under water and in outer space. Welding is a potentially hazardous
undertaking and precautions are required to avoid burns, electric shock, vision damage, inhalation of poisonous gases and fumes, and exposure to intense ultraviolet radiation. Until the end of the 19th century, the only welding process was forge welding,
which blacksmiths had used for centuries to join iron and steel by heating and
hammering. Arc welding and oxyfuel welding were among the first processes to develop late in the century, and electric resistance welding followed soon after. Welding
technology advanced quickly during the early 20th century as World War I and World War II drove the demand for reliable and inexpensive joining methods. Following the wars, several modern welding techniques were developed, including manual methods like shielded metal arc welding, now one of the most popular welding methods, as well as semi-automatic and automatic processes such as gas metal arc welding, submerged arc welding, flux-cored arc welding and electroslag welding. Developments continued with the invention of laser beam welding, electron beam welding, electromagnetic pulse welding and friction stir welding in the latter half of the century. Today, the science continues to advance. Robot welding is commonplace in industrial settings, and
researchers continue to develop new welding methods and gain greater understanding of weld quality.
These processes use a welding power supply to create and maintain an electric arc between an electrode and the base material to melt metals at the welding point. They can use either direct (DC) or alternating (AC) current, and consumable or
non-consumable electrodes. The welding region is sometimes protected by some type of inert or semi-inert gas, known as a shielding gas, and filler material is sometimes used
To supply the electrical power necessary for arc welding processes, a variety of different power supplies can be used. The most common welding power supplies are
constant current power supplies and constant voltage power supplies. In arc welding, the length of the arc is directly related to the voltage, and the amount of heat input is related to the current. Constant current power supplies are most often used for manual welding processes such as gas tungsten arc welding and shielded metal arc welding, because they maintain a relatively constant current even as the voltage varies. This is important because in manual welding, it can be difficult to hold the electrode perfectly steady, and as a result, the arc length and thus voltage tend to fluctuate. Constant voltage power supplies hold the voltage constant and vary the current, and as a result, are most often used for automated welding processes such as gas metal arc welding, flux cored arc welding, and submerged arc welding. In these processes, arc length is kept constant, since any fluctuation in the distance between the wire and the base material is quickly rectified by a large change in current. For example, if the wire and the base material get too close, the current will rapidly increase, which in turn causes the heat to increase and the tip of the wire to melt, returning it to its original separation distance.
The type of current used also plays an important role in arc welding. Consumable electrode processes such as shielded metal arc welding and gas metal arc welding generally use direct current, but the electrode can be charged either positively or negatively. In welding, the positively charged anode will have a greater heat
concentration, and as a result, changing the polarity of the electrode has an impact on weld properties. If the electrode is positively charged, the base metal will be hotter, increasing weld penetration and welding speed. Alternatively, a negatively charged electrode results in more shallow welds. Nonconsumable electrode processes, such as gas tungsten arc welding, can use either type of direct current, as well as alternating current. However, with direct current, because the electrode only creates the arc and does not provide filler material, a positively charged electrode causes shallow welds, while a negatively charged electrode makes deeper welds. Alternating current rapidly moves between these two, resulting in medium-penetration welds. One disadvantage of AC, the fact that the arc must be re-ignited after every zero crossing, has been
addressed with the invention of special power units that produce a square wave pattern instead of the normal sine wave, making rapid zero crossings possible and minimizing the effects of the problem.
One of the most common types of arc welding is shielded metal arc welding (SMAW) it is also known as manual metal arc welding (MMA) or stick welding. Electric current is used to strike an arc between the base material and consumable electrode rod, which is made of filler material (typically steel) and is covered with a flux that protects the weld area from oxidation and contamination by producing carbon dioxide (CO2) gas during
the welding process. The electrode core itself acts as filler material, making a separate filler unnecessary.
Shielded metal arc welding
The process is versatile and can be performed with relatively inexpensive equipment, making it well suited to shop jobs and field work. An operator can become reasonably proficient with a modest amount of training and can achieve mastery with experience. Weld times are rather slow, since the consumable electrodes must be frequently replaced and because slag, the residue from the flux, must be chipped away after welding. Furthermore, the process is generally limited to welding ferrous materials, though special electrodes have made possible the welding of cast iron, nickel, aluminum, copper, and other metals.
Diagram of arc and weld area, in shielded metal arc welding 1. Coating Flow 2. Rod 3. Shield Gas 4. Fusion 5. Base metal 6. Weld metal 7. Solidified Slag
and an inert or semi-inert gas mixture to protect the weld from contamination. Since the electrode is continuous, welding speeds are greater for GMAW than for SMAW.
A related process, flux-cored arc welding (FCAW), uses similar equipment but uses wire consisting of a steel electrode surrounding a powder fill material. This cored wire is more expensive than the standard solid wire and can generate fumes and/or slag, but it permits even higher welding speed and greater metal penetration.
Gas tungsten arc welding (GTAW), or tungsten inert gas (TIG) welding, is a manual welding process that uses a nonconsumable tungsten electrode, an inert or semi-inert gas mixture, and a separate filler material. Especially useful for welding thin materials,
this method is characterized by a stable arc and high quality welds, but it requires significant operator skill and can only be accomplished at relatively low speeds. GTAW can be used on nearly all weldable metals, though it is most often applied to stainless steel and light metals. It is often used when quality welds are extremely important, such as in bicycle, aircraft and naval applications. A related process, plasma arc welding, also uses a tungsten electrode but uses plasma gas to make the arc. The arc is more concentrated than the GTAW arc, making transverse control more critical and thus generally restricting the technique to a mechanized process. Because of its stable current, the method can be used on a wider range of material thicknesses than can the GTAW process and it is much faster. It can be applied to all of the same
materials as GTAW except magnesium, and automated welding of stainless steel is one important application of the process. A variation of the process is plasma cutting, an efficient steel cutting process.
Submerged arc welding (SAW) is a high-productivity welding method in which the arc is struck beneath a covering layer of flux. This increases arc quality, since contaminants in the atmosphere are blocked by the flux. The slag that forms on the weld generally comes off by itself, and combined with the use of a continuous wire feed, the weld deposition rate is high. Working conditions are much improved over other arc welding processes, since the flux hides the arc and almost no smoke is produced. The process is commonly used in industry, especially for large products and in the manufacture of welded pressure vessels. Other arc welding processes include atomic hydrogen welding, electroslag welding, electrogas welding, and stud arc welding.
This article is about the machining operation. For the generic use of the word, see rotating.
Roughing, or rough turning
set of curves or angles, but they are essentially linear (in the nonmathematical sense). Usually the term "turning" is reserved for the generation ofexternal surfaces by this cutting action, whereas this same essential cutting action when applied
to internal surfaces (that is, holes, of one kind or another) is called "boring". Thus the
phrase "turning and boring" categorizes the larger family of (essentially similar)
processes. The cutting of faces on the workpiece (that is, surfaces perpendicular to its rotating axis), whether with a turning or boring tool, is called "facing", and may be lumped into either category as a subset.
Turning can be done manually, in a traditional form of lathe, which frequently requires
continuous supervision by the operator, or by using an automated lathe which does not.
Today the most common type of such automation is computer numerical control, better
known as CNC. (CNC is also commonly used with many other types of machining besides turning.)
When turning, a piece of relatively rigid material (such as wood, metal, plastic, or stone)
is rotated and a cutting tool is traversed along 1, 2, or 3 axes of motion to produce
precise diameters and depths. Turning can be either on the outside of the cylinder or on
the inside (also known as boring) to produce tubular components to various geometries.
Although now quite rare, early lathes could even be used to produce complex geometric
figures, even the platonic solids; although since the advent of CNC it has become
unusual to use non-computerized toolpath control for this purpose.
The turning processes are typically carried out on a lathe, considered to be the oldest machine tools, and can be of four different types such as straight turning,taper
turning, profiling or external grooving. Those types of turning processes can produce
various shapes of materials such as straight, conical, curved, or groovedworkpiece. In general, turning uses simple single-point cutting tools. Each group of workpiece materials has an optimum set of tools angles which have been developed through the years.
The bits of waste metal from turning operations are known as chips (North America), or swarf (Britain). In some areas they may be known as turnings.
This operation is one of the most basic machining processes. That is, the part is rotated
while a single point cutting tool is moved parallel to the axis of rotation. Turning can be done on the external surface of the part as well as internally (boring). The starting material is generally a workpiece generated by other processes such
as casting, forging, extrusion, or drawing. 10.1.1.1Tapered turning
a) from the compound slide b) from taper turning attachment c) using a hydraulic copy attachment d) using a C.N.C. lathe e) using a form tool f) by the offsetting of the tailstock - this method more suited for shallow tapers.
The proper expression for making or turning a shape is to generate as in to generate a form around a fixed axis of revolution. a) using hydraulic copy
attachment b) C.N.C. (computerised numerically controlled) lathe c) using a form tool (a rough and ready method) d) using bed jig (need drawing to explain). 10.1.1.3Hard turning
Hard turning is a turning done on materials with a Rockwell C hardness greater
than 45. It is typically performed after the workpiece is heat treated.
The process is intended to replace or limit traditional grinding operations. Hard
turning, when applied for purely stock removal purposes, competes favorably with rough grinding. However, when it is applied for finishing where form and
dimension are critical, grinding is superior. Grinding produces higher dimensional accuracy of roundness and cylindricity. In addition, polished surface finishes of Rz=0.3-0.8z cannot be achieved with hard turning alone. Hard turning is
11.DESIGN AND FABRICATION
First solid shaft is taken and turned in the lathe shop to reduce the diameter and length according to the components which are present.
The steel plates are taken and they are made as case by welding,the welding used in this work is “arc welding”.
The Rack is fitted on the top such that it mates with freewheel to rotate in positive direction.
The sprocket is fitted outside the casing.
The sprocket is connected with the small sprocket which is attached with the dynamo.
The working part of the “Dynamo street lamps”includes,
The Rack which is welded with the iron plate is also welded with the compression coil(helical)spring.The Rack is positioned in such a way to mate the freewheel that makes the freewheel to rotate in positive direction.The ball bearings are used for positioning the shaft .The casing are done between the bearings using wooden plates.The wooden plate are punched in centre using carpentary tools.The order of components in shafts are BALL
BEARING1,FREE WHEEL1,FREE WHEEL2,FLY WHEEL,BALL BEARING2,LARGE SPROKET.The large sproket comes outside the casing.It is connected with the small sproket by the chaindrive.It is fitted in the speed brakers of the road.When a vehicle moves on the speed breakers,the rack is moved downwards and makes the freewheel to rotate in positive
direction,again the rack comes to the original position using the spring action.Due to this the shaft continuously rotate.The large sproket is mated with the small sproket whivh tends the dynamo also to rotate to generate power.
13.ADVANTAGES AND DISADVANTAGES ADVANTAGES
14.SPECIFICATION AND CALCULATION SPECIFICATION
15.COST ANALYSIS 16.CONCLUSION