CHAPTER 1

INTRODUCTION1.0 HISTORY OF ASHOK LEYLAND

Ashok Leyland is an Indian automobile manufacturing company based

in Chennai, India. Founded in 1948, the company is one of India's leading

manufacturers of commercial vehicles, such as trucks and buses, as well as

emergency and military vehicles. Operating six plants, Ashok Leyland also makes

spare parts and engines for industrial and marine applications. It sells about 60,000

vehicles and about 7,000 engines annually. It is the second largest commercial

vehicle company in India in the medium and heavy commercial vehicle (M&HCV)

segment with a market share of 28% (2007–08).

With passenger transportation options ranging from 19 seaters to 80 seaters,

Ashok Leyland is a market leader in the bus segment.The company claims to carry

over 60 million passengers a day, more people than the entire Indian rail network.

In the trucks segment Ashok Leyland primarily concentrates on the 16 ton to 25

ton range of trucks. However Ashok Leyland has presence in the entire truck range

starting from 7.5 tons to 49 tons. The joint venture announced with Nissan

Motors of Japan would improve its presence in the Light Commercial Vehicle

(LCV) segment (<7.5 tons).

Ashok Leyland's UK subsidiary Optare has shut down its bus factory in

Blackburn, Lancashire. This subsidiary's traditional home in Leeds has also been

vacated in favour of a purpose built plant at Sherburn in Elmet. Early products

included the Leyland Comet bus which was a passenger body built on a truck

chassis, sold in large numbers to many operators, including Hyderabad Road

Transport, Ahmedabad Municipality, Travancore State Transport, Maharashtra

State Transport and Delhi Road Transport Authority.

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By 1963, the Comet was operated by every State Transport Undertaking in

India, and over 8,000 were in service. The Comet was soon joined in production by

a version of the Leyland Tiger.

In 1968, production of the Leyland Titan ceased in Britain, but was restarted

by Ashok Leyland in India. The Titan PD3 chassis was modified, and a five speed

heavy duty constant-mesh gearbox utilized, together with the Ashok Leyland

version of the O.680 engine. The Ashok Leyland Titan was very successful, and

continued in production for many years.

Over the years, Ashok Leyland vehicles have built a reputation for reliability

and ruggedness. This was mainly due to the product design legacy carried over

from British Leyland.

Ashok Leyland had a collaboration with the Japanese company Hino Motors

from whom the technology for the H-series engines was bought. Many indigenous

versions of H-series engine were developed with 4 and 6 cylinder and also

conforming to BS2 and BS3 emission norms in India. These engines proved to be

extremely popular with the customers primarily for their excellent fuel efficiency.

Most current models of Ashok Leyland come with H-series engines.

In the journey towards global standards of quality, Ashok Leyland reached a

major milestone in 1993 when it became the first in India's automobile history to

win the ISO 9002 certification. The more comprehensive ISO 9001 certification

came in 1994, QS 9000 in 1998 and ISO 14001 certification for all vehicle

manufacturing units in 2002. In 2006, Ashok Leyland became the first automobile

company in India to receive the TS16949 Corporate Certification. Editor’s note:

This is part of a series of articles peeking into clean car industries and car

manufacturers of China, India, South Korea and Germany.

Among many other goals, Ashok Leyland aims to expand its operations to

penetrate into overseas markets. Included in the company’s plans is to acquire 2

smaller car manufacturers in China and in other developing countries. In October

2006, Ashok Leyland bought a majority stake in the Czech based- Avia. Called

Avia Ashok Leyland Motors s.r.o., this will give Ashok Leyland a channel into the

competitive European market. According to the company, in 2008 the joint venture

sold 518 LCVs in Europe despite tough economic conditions. Furthermore, the

company will expand its product offers into construction equipment, following a

joint venture with John Deere. Newly formed in June 2009, the John Deere

partnership is a 50/50 split between the companies. The company says negotiation

is progressing on land acquisition, and the production plans are in place.

The venture is scheduled to start rolling out wheel loaders and backhoe

loaders in October 2010. Aside from the full expansion planned for the company,

Ashok Leyland is also paying close attention to the environment. In fact, they are

one of the companies showing the strongest commitment to environmental

protection, utilizing eco-friendly processes in their various plants. Even as they

thrust into different directions, Ashok Leyland maintains an R&D group that aims

to uncover ways to make their vehicles more fuel efficient and reduce emissions.

When it comes to the development of environmentally friendly technologies,

Ashok Leyland has developed Hythane engines. In association with the Australian

company Eden Energy, Ashok Leyland successfully developed a 6-cylinder, 6-liter

92 kW BS-4 engine which uses Hythane (H-CNG,) which is a blend of natural gas

and around 20% of hydrogen. Hydrogen helps improve the efficiency of the engine

but the CNG aspect makes sure that emissions are at a controlled level. A 4-

cylinder 4-litre 63 KW engine is also being developed for H-CNG blend in a joint

1.1.1 iBUS

Ashok Leyland announced iBUS in the beginning of 2008, as part of the

future for the country's increasingly traffic-clogged major cities. Its Rs 60-lakh, 3

iBus, a feature-filled, low-floor concept bus for the metros revealed during the

Auto Expo 2008 in India, a vehicle for a first production run of pilot models should

be ready by the end of this year. The start of full production is scheduled for 2009.

Developed by a team of young engineers, the low-floored iBus will have the first

of its kind features, including anti-lock braking system, electronic engine

management and passenger infotainment.

The executive class has an airline like ambience with wide LCD screens,

reading lights, audio speakers and, for the first time, Internet on the move. A GPS

system enables vehicle tracking and display of dynamic route information on LCD

screens, which can also support infotainment packages including live data and

news. The bus will probably be equipped with an engine from the new Neptune

family, which Ashok Leyland also introduced at this exhibition, which are ready

for the BS4/Euro 4 emission regulations and can be upgraded to Euro 5.

1.1.2 DOST

DOST is a 1.25 ton light commercial vehicle (LCV) that is the first product

to be launched by the Indian-Japanese commercial vehicle joint venture Ashok

Leyland Nissan Vehicles. Dost is powered by a 55 hp high-torque, 3-cylinder,

turbo-charged Common Rail Diesel engine and has a payload capacity of 1.25

Tonnes. It is available in both BS3 and BS4 versions. The LCV is being produced

in Ashok Leyland's plant in Tamil Nadu's Hosur.

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1.1.3 ASHOK LEYLAND DEFENCE SYSTEMS

Ashok Leyland Defence Systems (ALDS) is a newly floated company by the

Hinduja Group. Ashok Leyland, the flagship company of Hinduja group, holds 26

percent in the newly formed Ashok Leyland Defence Systems (ALDS). The newly

floated company has a mandate to design and develop defence logistics and tactical

vehicles, defence communication and other systems. Ashok Leyland is the largest

supplier of logistics vehicles to the Indian Army. It has supplied over 60,000 of its

Stallion vehicles which form the Army's logistics backbone.

1.1.4 SHOPS IN ASHOK LEYLAND

1.1.4.1 ENGINE ASSEMBLY

STAGE 1: CAM BEARING

Cam bearings are attached to the crankcase of the engine.

STAGE 2: CAM SHAFT

Cam shaft is attached in the crankcase.

STAGE 3: CRANK SHAFT

It is fixed at the base end of crankcase.

STAGE 4: STUDS

M14 studs are fixed to the holes of crankcase.

STAGE 5: TIMING BRAKE PLATE

It is fixed to the side of the engine.

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STAGE 6: CAM GEAR

It is placed on the crankcase to operate cam shafts and to operate valves.

STAGE 7: FLYWHEEL

The flywheel is placed on housing; it also consists of seal housing and flange.

STAGE 8: OIL PUMP

It is fixed at top of crankcase. It is used to circulate oil to various parts of engine.

STAGE 9: PISTON

The piston is attached inside the bore of crankcase & it is connected to crankshaft. The oil ring and compression rings are also attached on the piston.

STAGE 10: CONROD BOLT

It is used to connect piston with crankshaft.

STAGE 11: IDLING GEAR

It is used to control the rotations of cam gear, crank gear and compression gear.

STAGE 12: CYLINDER HEAD

It is attached at the top of crankcase.

STAGE 13: OIL SUMP

It is placed at the bottom of crankcase.

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STAGE 14: ROCKER

Rocker is fixed with cylinder head.

STAGE 15: AIR COMPRESSOR

It is fixed with crankcase.

STAGE 16: FUEL INJECTION PUMP

STAGE 17: VALVE COVER

STAGE 18: OIL COOLER

STAGE 19: INJECTOR PIPE

STAGE 20: INLET MANIFOLD

STAGE 20: SIDE COVER

STAGE 21: WATER PUMP

STAGE 22: STARTER MOTOR

STAGE 23: EXHAUST MANIFOLD

STAGE 24: TURBO CHARGER

STAGE 25: EII FITMENTS

STAGE 27: FULLY ASSSEMBLED

Finally, the assemble is taken to the testing section for checking the performance.

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1.1.4.2 SHOP III

FRAME ASSEMBLY

There are several steps involved in frame assembly. They are as follows:

The side members and engine mounting are lifted using conveyor.

Assemble all cross members, steering mounting bracket, air cooler mounting bracket and rear spring brackets.

On rear end of the frame, both sides are aligned with taper pin.

Cross members are tightened well. Fit and tight FS and BKTS on both sides with dummy bolts.

Reaming process is done in the next step and the dummy bolts are removed.

Torque tightening in the rear brackets using M14 bolts on both sides.

Front and rear ends are fixed with four cab mountings.

Tighten the CB cross members using brake elbow adaptors.

Tilt the frame by 180o using tilting CUM lifting equipment.

Punch frame Sl. No. and spec on rear end of RH FSM.

Air blow the reamed burrs in assembled frame.

Lift and unload the assembled frame from conveyor on to trolley using tilting CUM lifting equipment.

Finally, the whole frame is carried to chassis assembly centre.

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1.1.4.3 SHOP IV

The shop IV is classified into two departments. They are given below:

o Rear axle assembly.

o Front axle assembly.

REAR AXLE ASSEMBLY

The rear axle assembly consists of several stages. They are shown below:

Load rear axle casing on pedestals and remove wire strip, axle shafts.

Assemble dust covers on brake shoes and tighten with bolts and nuts.

Apply torque on mounting nuts.

Assemble inner ring for oil seal.

Distance piece is fixed to align the outer and inner wheel bearings in the same axis.

Fix the wheel drum.

Punch the Sl. No. on the rear axle.

Unload rear axle from conveyor and it is taken to the chassis assembly centre.

FRONT AXLE ASSEMBLY

The front axle assembly consists of several stages. They are discussed below:

First, the axle beam is loaded at conveyor belt.

The number is punched in the axle beam.

Next, the axle arm is fixed to beam of steering with pin fin and cotter pin using dummy bolts.

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The tracking rod is fixed for the alignment of wheel. This will helps the left side of the tyre to turn along with the right side wheel.

Fix the air chamber and brake shoe.

Fix the hub and lock set using axle arm.

Fix the wheel drum to the both ends of axle arm.

Unload front axle from the conveyor and it is taken to the chassis assembly.

1.1.4.4 CHASSIS ASSEMBLY

The chassis assembly consists of 14 stages. They are discussed below:

In stage- 1, the front and rear axle is fixed on the main frame which is already fabricated from shop 3.

In stage- 2, the fr4ame assembly is placed on the conveyor belt, and then brake chamber is fitted into it.

In stage- 3, the steering gear box is fitted to the main frame.

In stage- 4, the propeller shaft is connected into the gear box flange. This propeller shaft is also coupled with universal joint.

In stage-5, the Vehicle Identification Number (VIN) is punched into the frame.

In stage- 6, the silencer tank is fixed into the main frame.

In stage- 7, the air tank and fuel tank is fixed at the rear end.

In stage- 8, the engine is mounted on the frame.

In stage- 9, the radiator is fixed at the front end of engine.

In stage- 10, the lever, fuel filter and accelerator assembly is linked with the engine.

In stage- 11, the tyres for the wheels are fitted to the wheel drum.

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In stage- 12, the battery box and cross bumpers are fitted.

In stage-13, the diesel is filled into the fuel tank.

Finally, the vehicle is taken to another unit for checking its performance.

1.1.4.5 SHOP II

In this shop, the components used for engine assembly may be manufactured

from this department. The facing and centering of the valves are also done in this

shop. The parts that are manufactured from this shop are as follows:

Cylinder head

Camshaft

Connecting rod

Piston

Con rod bolt

Crankcase

Spiral gear

Compound gear

For the preparation of con rod bolt, the workpiece is fitted in the multi spindle

lathe and the following processes will be done.

Head forming

Step turning

Chamfering

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In the camshaft, the processes like taping, drilling, milling, grinding,

tempering, checking hardness are done in this shop II. The gear hobbing is also

done with the help of gear hobbing machine, after that the oil hole drilling may

proceeds. The journal bearing grindings and the cam grindings are done here. The

flywheel housing is tested and fitted at engine case. Finally, the parts are taken to

another department for assemble.

1.2 LIFTING TACKLE

Lifting Tackle is a lifting equipment driven by mechanical power or

electrical power. It is used to raise, lower, suspend or transport load of different

objects like Passenger cowl & hub of vehicles. In the lifting tackle, two motors are

used to raise and lower the tackle frame. Motor shafts- coupled with chain slings.

Each chain slings are connected with grab hook to carry the frame. The frame

consists of two horizontal cross bars arranged to fix the block of weight. There are

two sprockets linked together with roller chain. In order to balance equal weight

while carrying vehicle hub or heavy objects; a weight is kept horizontally with

cross bar. A pulley and rope arrangement is provided at one end of the cross bar.

The pulley line is coupled with sprocket for adjusting the weights, so the hub

weight may be balanced and the hub may be placed perfectly on the chassis.

An electro-mechanical appliance whose principal function is lifting or

lowering, or both, of loads with a calibrated short link or roller chain between the

sheave and the lifting block. After the trolley has been installed on the travel rail,

always install a stopper on the end of the travel rail to prevent the trolley from

dropping off. The stopper is made up of rubber to absorb the shock when the

trolley strikes the stopper. The maximum safe working load in Kgs/ tonnes that the

hoist is designed to carry in service. This shall be specified by the manufacturer of

the hoist and marked boldly and clearly on the hoist and hook block.

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fig.1.1 lifting tackle

ELECTRIC BRAKE ASSEMBLY

The correct air gap between armature and field, when brake is not energized,

is 0.025 inch (0.635 mm) and need not be adjusted until the gap reaches 0.045

inches (1.14 mm). When checking brake gap, always reset to 0.025 inch (.0635

mm). To adjust the brake, proceed as follows:

1. Disconnect hoist from power supply.

2. Remove back frame cover.

3. Before adjusting the gap:

4. Turn adjusting nuts clockwise gaging the air gap at both ends.

5. Replace cover, reconnect the power and check operation.

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1.2.1 CHAIN HOIST

A chain hoist is a mechanical device used for lifting heavy loads of objects

and equipment. It is made with a pulley, which is held together by a closed chain.

The closed chain in the chain hoist forms a loop, which makes it easy to be pulled

by hand.

There are several large and small pulleys located throughout a chain hoist.

One large and one small pulley are situated on the same axle of the chain hoist.

There is also a mobile pulley on the chain hoist that holds the load in place.

For the load to be raised with the chain hoist, the closed chain has to be pulled.

When it is pulled, the large pulley draws in more chain than what is released by the

smaller side. From here, the lifting process begins.

Although the history of pulleys is unclear, it is known that primitive

methods were employed to move heavy objects around. One of the early attempts

at a pulley system was the single fixed pulley, which failed because friction

prevented the wheel from being turned. Rope pulleys, which were commonly used

for pulling water out of wells and are still in use today, are thought to have been

invented next.

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1.3 TERMINOLOGY OF LIFTING TACKLE:

For the purpose of this standard, the following definitions shall apply.

1.3.1 ELECTRIC CHAIN HOIST

An electro-mechanical appliance whose principal function is lifting or

lowering, or both, of loads with a calibrated short link or roller chain between the

sheave and the lifting block.

1.3.2 CAPACITY OR SAFE WORKING LOAD

The maximum safe working load in Kgs/ tonnes that the hoist is designed to

carry in service. Applied loads shall include all handling devices used, such as

buckets, magnets and grabs.

1.3.3 BASIC AND PERMISSIBLE STRESS

All permissible stresses specified in IS 800, IS 816 and IS 1024 are basic

stresses for the purpose of this standard, and the permissible stresses in this

standard are basic stresses applied with the applicable duty factor.

1.3.4 HEIGHT OF LIFT

The distance between the upper most and lowest limits of travel of the hook block.

1.3.5 HOISTING SPEED

The velocity in metres per minute at which the hoist will lift the rated load.

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1.3.6 HEAD ROOM

Measured with the hook block in the highest position with full load, and it is

the distance between the saddle of the hook block and the following points:

a) The top of the lug or centre line of suspension holes on lug suspended hoists,

b) The saddle of the top hook on hook suspended hoists.

c) The bottom of the beam or rail on trolley suspended hoists.

1.3.7 LUG SUSPENDED HOIST

A hoist whose upper suspension members are lugs.

1.3.8 HOOK SUSPENDED HOIST

A hoist whose upper suspension member is a hook.

1.3.9 TROLLEY

A wheeled carriage from which the hoist is suspended. The trolley may be

push type, handgeared or motor-driven type.

1.3.10 TROLLEY SUSPENDED HOIST

A hoist whose upper suspension member is a trolley for the purpose of travel

on a suitable runway.

1.3.11 ELECTRIC DYNAMIC BRAKE

An electric motor acting as a brake by regenerative counter torque or

dynamic means.

1.3.12 ELECTRICALLY OPERATED BRAKE16

A friction-brake actuated or controlled by electric / electromagnetic means.

1.3.13 LIMIT SWITCH

A device to cut off the power to motor automatically at both ends of hook

path or at any desired limit of travel.

1.4 ELECTRICAL CHARACTERISTICS

Clearly specified electrical characteristics consisting of voltage, phases,

cycles if ac power is used, and voltage only if dc power is used.

1.4.1 LOAD SPROCKET

A hoist component that transmits motion to the load chain. This component

is also called load chain wheel.

1.4.2 IDLER SPROCKET

A freely rotating device that changes the direction of the load chain. This

device is sometimes called idler wheel, idler sheave, pocket wheel or chain wheel.

1.4.3 HOOK BLOCK OR LOAD BLOCK

The assembly of lower load hook or shackle, swivel, bearing, pins, sprocket and

frame suspended by the load chain.

1.4.4 LOAD CHAIN

The load lifting chain in the hoist. It shall be a calibrated short link chain as

per IS 6216 or a calibrated roller chain when in agreement with the user. A small

amount of lubricant will greatly increase the life of load chain. Do not allow the

chain to run dry. Keep it clean and lubricate at regular intervals with Lubriplate,

Bar and Chain Oil 10-R (Fiske Bros. Refining Co.) or equal lubricant.17

Normally, weekly lubrication and cleaning is satisfactory, but under hot and

dirty conditions, it may be necessary to clean the chain at least once a day and

lubricate it several Times between cleanings. When lubricating the chain, apply

sufficient lubricant to obtain natural run-off and full coverage.

1.4.5 REEVING

A system in which a chain travels around sprockets.

1.5 PENDANT STATION

Electrical controls station with push button suspended from the hoist for

operating the unit.

Usage of electric chain hoists shall be generally limited to a maximum lift

height of 20 metres for safety reasons. Manufacturers may offer higher lifts

according to their experience and design in special cases of application in mutual

agreement with buyer. In such cases, based on the time of duration of use, quality

of chain and the class of duty of the chain hoist, lifting chain shall be specially

selected to suit the application.

1.6 BEARINGS

A bearing is a device to allow constrained relative motion between two or

more parts to only the desired type of motion. This is typically to allow and

promote free rotation around a fixed axis or free linear movement; it may also be

to prevent any motion, such as by controlling the vectors of normal forces.

Bearings may be classified broadly according to the motions they allow and

according to their principle of operation, as well as by the directions of applied

loads they can handle.

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All bearings and bushings except the lower hook thrust bearing are

prelubricated and require no lubrication. Lubricate the lower hook thrust bearing at

least once a month, using heavy cup grease.

1.6.1 MOTIONS

Common motions permitted by bearings are:

Axial rotation e.g. shaft rotation.

Linear motion e.g. drawer.

Spherical rotation e.g. ball and socket joint.

Hinge motion e.g. door, elbow, and knee.

1.6.2 TYPES OF BEARING

1.6.2.1 PLAIN BEARING

A plain bearing, also known as a plane bearing or a friction bearing is the

simplest type of bearing, comprising just a bearing surface and no rolling elements.

Therefore the journal slides over the bearing surface.

The simplest example of a plain bearing is a shaft rotating in a hole. A

simple linear bearing can be a pair of flat surfaces designed to allow motion; e.g., a

drawer and the slides it rests on or the ways on the bed of a lathe. Plain bearings, in

general, are the least expensive type of bearing. They are also compact and

lightweight, and they have a high load-carrying capacity.

1.6.2.2 ROLLING ELEMENT BEARING

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A rolling-element bearing, also known as a rolling bearing, is a bearing

which carries a load by placing round elements between the two pieces. The

relative motion of the pieces causes the round elements to roll with very little

rolling resistance and with little sliding.

One of the earliest and best-known rolling-element bearings are sets of logs

lay on the ground with a large stone block on top. As the stone is pulled, the logs

roll along the ground with little sliding friction.

As each log comes out the back, it is moved to the front where the block

then rolls on to it. It is possible to imitate such a bearing by placing several pens or

pencils on a table and placing an item on top of them.

1.6.2.3 JEWEL BEARING

Fig 1.2 (jewel bearing)

A jewel bearing is a plain bearing in which a metal spindle turns in a jewel-

lined pivot hole. The hole is typically shaped like a torus and is slightly larger than

the shaft diameter. The jewel material is usually some form of synthetic sapphire,

such as ruby. Jewel bearings are used in precision instruments, but their largest use

is in mechanical watches. Historically, jewel pivots were made by grinding using

diamond abrasive. Modern jewel pivots are often made using high-powered lasers,

chemical etching, and ultrasonic milling.

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1.6.2.4 FLUID BEARING

Fig 1.3 (fluid bearing)

Fluid bearings are bearings which support the bearing's loads solely on a thin

layer of liquid or gas. Hydrostatic bearings are externally pressurized fluid

bearings, where the fluid is usually oil, water or air, and the pressurization is done

by a pump. Hydrodynamic bearings rely on the high speed of the journal self-

pressurizing the fluid in a wedge between the faces.

Fluid bearings are frequently used in high load, high speed or high precision

applications where ordinary ball bearings have short life or high noise and

vibration. They are also used increasingly to reduce cost. For example, hard

disk drive motor fluid bearings are both quieter and cheaper than the ball bearings

they replace. Hydrodynamic bearings rely on bearing motion to suck fluid into the

bearing and may have high friction and short life at speeds lower than design or

during starts and stops. An external pump or secondary bearing may be used for

startup and shutdown to prevent damage to the hydrodynamic bearing.

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1.6.2.5 MAGNETIC BEARINGS

Fig 1.4(magnetic bearings)

A magnetic bearing is a bearing which supports a load using magnetic

levitation. Magnetic bearings support moving machinery without physical contact;

for example, they can levitate a rotating shaft and permit relative motion with very

low friction and no mechanical wear. Magnetic bearings are in service in such

industrial applications as electric power generation, petroleum refining, machine

tool operation, and natural gas pipelines. They are also used in the Zippe-type

centrifuge used for uranium enrichment.

Magnetic bearings are used in turbo molecular pumps, where oil-lubricated

bearings would be a source of contamination. Magnetic bearings support the

highest speeds of any kind of bearing; they have no known maximum relative

speed.

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1.6.2.6 PLUMMER BLOCK BEARING HOUSING

Fig 1.5 (Plummer block bearing housing)

Solid Plummer block housings are housing that hold rolling element

(ball)bearings.Theirdesignelementsinclude:

Cast iron, cast steel, machined steel or rolled steel housing.

Permits moderate initial misalignment.

Simple, versatile and economic housing/bearing combination.

Typical applications include: conveyor rolls, press rolls, conveyor deck etc.

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CHAPTER 2

LITERATURE REVIEW

2.0 MECHANICAL REQUIREMENTS:

2.1 DESIGN:

The materials used in the construction of hoists shall be properly selected for

the stresses encountered when the equipment is used in accordance with the

manufacturer's recommendations. The design of the component parts of the hoist

shall include due allowance for the effects of the duty which the mechanism will

perform in service.

2.1.1 DESIGN ON STRENGTH BASIS

In the design of a component on the basis of ultimate strength, the value of

the stress factor used shall be the basic stress factor multiplied by the duty factor

for the appropriate hoist class; where basic stress factor shall be not less than 4 and

the duty factor shall be as given in Table I for the respective mechanism. Normally

the lifting tackles are designed to offer M2 to M6.

2.1.2 DESIGN ON DYNAMIC LOAD BASIS

Power transmission parts shall be designed so that the dynamic stresses

calculated for the rated load shall not exceed the fatigue and endurance limit of the

material used.

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2.1.3 DESIGN ON LIFE BASIS

Components designed on the basis of life shall have a rated life of not less

than 10 years of 250 days per year for Class, M3 300 days per year for Class M5,

and 333 days per year for Class M6 The running hours per day or the life in hours

used for the purpose of the design of the components shall be the value specified in

Table 1 for the appropriate class.

2.1.4 WELDING

Steel parts may be joined by any fusion-welding process. The design shall

be such that the maximum permissible stresses in the welds.

2.2 LOAD CHAIN AND ACCESSARIES

2.2.1 LOAD CHAIN AND CHAIN ANCHORAGES

Load chain shall be grade G or higher made of alloy steel, machine

calibrated, heat treated and proof tested short link, so that the finished hoist chain

complies with mechanical properties.

TABLE I25

DUTY FACTOR & LIFE OF MECHANISM:

MECHANISM

CLASS

DUTY FACTOR AVERAGE LIFE

Sl. No As per

IS 13834

Strength Wear Running Hours

Per Day

Total Life

Hours

i M2, M3 1.0 0.4 0.5 Over1250

ii M5 1.2 0.5 1.5 Over4500

iii M6 1.4 0.6 3.0 Over

10000

2.3 CHAIN WHEELS

2.3.1 MATERIAL

The load chain drive wheel shall be of alloy steel material and heat treated to

adequate strength suitable for use with the load chain employed. Iron castings of

spheroidal or nodular graphite conforming to IS 1865 may also be used which is of

adequate strength and hardened or chilled to match the load chain employed.

2.3.2 DESIGN

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The design of the load chain wheel drive shall be such as to ensure effective

operation with the load chain. The load chain wheel shall have pockets accurately

machined to fit the links, load chain which shall operate freely and smoothly over

the load wheel and without damage to the chain. Minimum number of pockets on

the load wheel shall be four. Sprocket type wheels for roller chain shall be

machined / shaped from alloy steel heat treated material.

2.3.3 CHAIN GUIDE

Enclosed chain guides shall be provided to ensure that the hoist load chain

enters the sprocket in the proper position to prevent misalignment or jamming of

the hoist load chain and chain wheel. These guides, if bolted on, shall have means

to prevent loosening under vibration. Where roller guides are used, the edges of

their centre groove shall be chamfered to prevent damage to the load chain.

2.3.4 CHAIN STRIPPER

A chain stripper may be provided for binding of the chain from the sprocket

while unwinding or entering.

2.3.5 CHAIN COLLECTOR

Chain shall be freely suspended and where necessary a chain collector shall

be fitted. The chain collector shall be so designed as to permit the chain to enter the

chain block in a manner that will not damage the chain or chain block and allow

smooth flow out of the container.

2.4 HOOKS AND HOOK FITTINGS27

2.4.1 HOOKS

Hooks shall closed die and alloy steel forged, all hooks shall be equipped

with latches.

2.4.2 CROSSHEADS

Unless otherwise approved, hook crosshead shall be of a single-piece steel

construction.

2.4.3 TRUNNIONS

Trunnions shall project through the cheek plates of the blocks by not less

than 3 mm and shall incorporate means for preventing the spreading of cheek

plates. Where a trunnion is of the oscillating type adequate bearing surfaces shall

be provided.

2.5 TROLLEYS

Trolleys shall motor operated type. The electric driven trolley shall be

provided with a stopper. After the trolley has been installed on the travel rail,

always install a stopper on the end of the travel rail to prevent the trolley from

dropping off.

28

Fig. 2.1 (motorized trolley)

2.5.1 DAMPER

The stopper should be used with rubber or other shock absorbing material to

absorb the shock when the trolley strikes the stopper.

Fig. 2.2 damper

29

Technical Specifications of electric motor:Capacity = 1800 kg

Hoisting speed = 1m/min

H.P of motor = 1.5

2.6 CHAIN SLING

Chain slings are made up of alloy Steel. Chain has the advantage of being

better suited for lifting rough loads and withstanding high temperatures. Lifting

chains are ideal for environments where you need extra strength and durability for

lifting heavy loads. Lifting chain offers superior flexibility and can withstand

environmental hazards like excessive heat that can undermine the integrity of other

sling materials. Chain slings suppliers can customize the configuration of your

chain sling for an exact match to your lifting needs.

Only alloy chain slings should be used for overhead lifting chain

applications.  Grade 80 Chain and Grade 100 Chain are the preferred grade used

for all of our chain lifting slings.  

Alloy grade 80 chain slings offer the strength and durability required of a

lifting chain that will be used for the toughest of jobs. This grade of lifting chain

also offers the best performance under high temperatures or under other harsh

conditions that would destroy other types of lifting slings.  Grade 100 chain is

increasing in popularity as many chain sling suppliers are converting to this

stronger, yet lighter grade. 

30

2.6.1 SLING HOOKS

2.6.1.1 SLIP SLING HOOK

A large throat hook used primarily at the ends of wire rope and chain slings.

Usually self-locking to avoid disconnect.

2.6.1.2 GRAB SLING HOOK

A small throat hook that attached to the chain by sliding over the chain in

between links. This hook locks into place by 'grabbing' the chain and will not slide

along the chain.

Fig 2.3 Chain sling

2.7SPROCKET MATERIALS

The sprocket materials are classified as follows:

Heat resisting steels

Heat resisting alloys

Nickel based alloys

Special alloys:

1. Alacrite (cobalt based alloys)

31

2. Adnick (Nickel based alloys)

2.8CHARACTERISTICS OF SPROCKET MATERIALS

It should resist inter crystalline corrosion.

It should work above 7500C.

It should have high temperature characteristics.

Resistance to hot turbine gases.

Saline corrosion resistance.

It should withstand oxidation upto 11000 C.

Good mechanical properties at elevated temperature.

32

CHAPTER 3

DESIGN

3.1 MANUAL BALANCING METHOD

In the lifting tackle, two motors are used to raise and lower the tackle frame.

Motor shafts- coupled with chain slings. Each chain slings are connected with grab

hook to carry the frame. The frame consists of two horizontal cross bars arranged

to fix the block of weight. There are two sprockets linked together with roller

chain. In order to balance equal weight while carrying vehicle hub or heavy

objects; a disc plate is kept horizontally with cross bar. A pulley and rope

arrangement is provided at one end of the cross bar. The pulley line is coupled

with sprocket for adjusting the weights (disc plate), so the hub weight may be

balanced and the hub may be placed perfectly on the chassis.

3.2 SELF BALANCING METHOD

In this technique, two sprockets (spr c and spr d) are additionally coupled

with the sprocket (a) and sprocket (b). The sprockets are coupled using shafts. The

sprockets (c) and (d) are linked with a chain drive (duplex chain). The ends of the

chain are attached with hooks, which is used to lift the hub. Due to heavy weight

at one side of hub, the lifting process becomes unbalance.

When hub slides at the right side of the tackling frame, the sprocket (c) and

(d) will rotates at clockwise direction. During this rotation, the power will be

transmitted from sprocket (c) and (d) to sprocket (a) and (b) respectively.

33

However, the rotation of sprocket (a) and (b) leads to move the disc plates

located at the cross bar of frame. When the disc plate moves through a certain

distance, the hub weight would be balanced.

3.3 DESIGN OF CHAIN DRIVE

For a given speed, the power capacity increases with the number of teeth on

the chain sprocket. Of course, the larger the number of teeth, the larger the

diameter of the sprocket. Note that the use of a chain with a small pitch on a large

sprocket produces the quieter drive.

The manufacturers’ ratings are for a single strand of chain. Although

multiple strands do increase the power capacity, they do not provide a direct

multiple of the single-strand capacity. The capacity for 2, 3, and 4 strand systems

are 1.7, 2.5 and 3.3 respectively.

The manufacturers’ ratings are for a service factor of 1.0. The designer must

specify a service factor for a given application based on the type of driver and load

for that system. The following are general recommendations for designing chain

drives:

The minimum number of teeth in a sprocket should be 17 unless the drive is

operating at a very low speed, under 100 rpm.

The maximum speed ratio should be 7.0, although higher ratios are feasible.

Two or more stages of reduction can be used to achieve higher ratios.

The center distance between the sprocket axes should be approximately 30

to 50 pitches.

34

The arc of contact of the chain on the smaller sprocket should be no smaller

than 120°.

The larger sprocket should normally have no more than 120 teeth.

The preferred arrangement for a chain drive is with the centerline of the

sprockets horizontal and with the tight side on top.

The chain length must be an integral multiple of the pitch, and an even

number of pitches is recommended.

The center distance should be made adjustable to accommodate the chain

length and to take up for tolerances and wear. Excessive sag on the slack side

should be avoided, especially on drives that are not horizontal. A convenient

relation between center distance (C), chain length (L), number of teeth in the small

sprocket (N1), and number of teeth in the large sprocket (N2), expressed in pitches,

is

The exact theoretical center distance for a given chain length, again in

pitches, is

The theoretical

center distance assumes no sag in either the tight or the slack side of the chain, and

thus it is a maximum. Negative tolerances or adjustment must be provided.

3.4 ALIGNMENT OF CHAIN DRIVE

To obtain maximum service-life and efficiency from a chain drive, it is

necessary that certain precautions in installation be taken. Chain drive installation

35

is relatively simple and good results may be obtained when the following

conditions are met:

1. The roller chain, sprockets, and other components are in good condition.

2. The sprockets are properly aligned.

3. Provision is made for adequate lubrication.

4. The chain is correctly tensioned.

a) Condition of Components

Shafting, bearings, and foundations should be supported rigidly to maintain

the initial alignment. Roller chain should be free of grit and dirt. Wash chain in

kerosene when required.

b) Drive Alignment

Misalignment results in uneven loading across the width of the chain and

may cause roller link plate and sprocket tooth wear. Drive alignment involves two

things: parallel shaft alignment and axial sprocket alignment.

Shafts should be parallel and level. This condition may be readily checked

by the use of a feeler bar, and a machinist's level. It there is axial movement

of the shaft, lock the shaft in the normal running position before aligning the

sprockets.

36

(fig. 3.1 aligning shafts))

Normally, it is good practice to align the sprockets as close to the shaft

bearing as possible.

On drives with long spans, it may be necessary to support the chain with a

plank or bar as the connection is made.

Sprocket axial alignment can be checked with a straight edge which will

extend across the finished sides of the two sprockets. Normally, it is good

practice to align the sprockets as close to the shaft bearing as possible. For

long center distances, use a taut cord, or wire long enough to extend beyond

each of the sprockets.

fig 3.2 aligning sprockets

c) Installing the Chain37

Recheck all preceding adjustments for alignment and make certain all

setscrews, bolts and nuts are tight. Fit chain around both sprockets and bring the

free ends together on one sprocket for connection, the sprocket teeth will locate the

chain end links. Install the connecting link, and connecting link cover plate, and

the spring clip or coffer pins. On larger pitch chains or heavy multiple strand, it

may be necessary to lock the sprockets for this operation. After more research was

done the perception of using more than three blades was no longer a factor.

Currently, the most recent windmills are equipped with two or three blades.

When press fit cover plates are used, be careful not to drive the plate on so far as to

grip the roller links. Stiff joints can result if this is done. On drives with long spans,

it may be necessary to support the chain with a plank or bar as the connection is

made.

d) Chain Tension

Check chain tension to be certain the slack span has 4-6% mid-span movement in

horizontal drives and 2-3% in vertical drives.

Fig 3.3 terminology of sprocket

38

3.5 ROLLER CHAIN:

Fig 3.4 roller chain

39

Fig 3.5 Duplex Sprocket

3.5 SELECTION OF ROLLER CHAIN DRIVES

The following data should be taken into consideration while selecting roller

chain drives

a) Horsepower to be transmitted

b) RPM of the driving and driven sprocket (speed ratio)

c) Load classification

d) Space limitations if any

e) Driven machine

f) Source of power

If the pitch centre distance and number of teeth on both driving and driven

sprockets are known, you can use the following formula, tables and charts to

calculate chain lengths.40

3.5.1 SELECTION PROCEDURE

For maximum service life, smooth operation and optimum performance, the

following points should be considered, while determining the number of teeth in

the pinion.

a) As most drives have an even number of pitches in the chain, the use of a

pinion with an odd number of teeth ensures even distribution of chain and

wheel tooth wear.

b) Pinions for normal, stead drives should generally not have less than 17 teeth,

the reason being that a chain forms a polygon around the pinion. When the

pinion speed is constant, the chain speed is subject to regular cyclic

variation. The percentage of cyclic variation becomes less marked as the

number of teeth increases – and in fact becomes insignificant for the

majority of applications when the number of teeth in the pinion exceeds 17.

c) A minimum of 23 teeth is recommended on moderate shock drives where

the speed of the pinion exceeds 50 % of the maximum rated speed, and for

heavy shock drives where the speed of the pinion exceeds 25% of the

maximum rated speed.

d) The pinion should be heated to HV 10- 550 for smooth drives where the

pinion speeds exceeds 70% of the maximum speed and operates under full

horsepower rating. For heavy shock drives, the pinion be treated in all cases.

3.5.2 DETERMINE CHAIN LENGTH:

41

Compute the length of chain required using the formula given below. I

possible, adjust the centre distance , so that the length of chin required is always in

an even number of pitches. For optimum life of the chain and sprockets the centre

distance between the two sprockets should be 30 to 50 times the chain pitch.

where,

L- Chain length in pitches

P- Chain pitch

C- Contemplated centre distance

N- Number of teeth on large sprocket

n - Number of teeth on small sprocket

fig. 3.6 lifting tackle- frame (1)

42

fig. 3.7 lifting tackle- frame (2)

3.5.3 MATERIAL SPECIFICATIONS:

Type Material

Sprocket Duplex Sprocket Alloy Steel(C43)

Chain Roller chain Stainless steel

Hook Slip hook

Grab hook

Stainless steel

Chain Sling - Alloy Steel

43

Pin - Mild steel

Bush - Stainless steel

Rollers - Stainless steel

Link Plates - Alloy Steel(C20)

CHAPTER 4

CALCULATION

4.1 SELECTION OF NUMBER OF TEETH ON SPROCKET

Transmission ratio; i= 1

Driver sprocket, z1= 30

Driven sprocket, z2= 30

4.2 SELECTION OF STANDARD PITCH

Standard pitch, p= 15.875 mm

4.3 SELECTION OF CHAIN

44

Chain type: Duplex chain DR50 (from table 1.0)

4.4 CALCULATION OF SERVICE FACTOR

Service factor, ks= k1.k2.k3.k4.k5.k6

From tables 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7

k1= 1.25

k2= 1.25

k3= 0.8

k4= 1

k5= 0.8

k6= 1.25

Service factor, ks= 1.25 x 1.25 x 0.8 x 1 x 0.8 x 1.25

Service factor, ks= 1.25

4.5 DETERMINATION OF LOAD

Load, PT = 450 kg = 450 x 9.81

Load, PT = 4414.5 N

Design Load = Load x service factor

Design Load = PT x ks

Design Load = 4414.5 x 1.25

Design Load = 5518.12 N

4.6 CALCULATION OF WORKING FACTOR OF SAFETY

Factor of safety = Breaking Load/ Design Load

Breaking Load = 4440 kgf= 44400N

Factor of safety = 44400/5518.1245

Factor of safety = 8.4

4.7 CHECK FACTOR OF SAFETY

Minimum value of factor of safety = 7 (from table 2.0)

Working factor of safety = 8.4

Working Factor of safety> Minimum Factor of safety

Hence design is safe.

4.8 CHECK BEARING STRESS

Velocity, v = z1pN/6

v = 30 x 15.875 x 50/60

v= 396.87 mm/s

v = 0.39 m/s

Bearing Area = 140mm2

Weight per metre = 1.78kgf

Power transmitted basis of breaking load, N= Q x v/ (102.n.ks)

Where,

Q- Breaking Load= 4440 kgf

Power, N= 4440 x 0.39 / (102 x 7 x 1.25)

Power, N= 1.94 kW

Bearing stress,

σ =102.ks.N/A.V46

σ = 102 x 1.25 x 1.94/ 140 x 0.39

σ = 29.6 N/mm2

Allowable bearing stress = 35 N/mm2 (from table 2.1)

Allowable bearing stress > Induced Stress

4.9 CALCULATION OF LENGTH OF CHAIN

Number of links, lp= 2ap + (z1+z2)/2 + [(z2 – z1/2π)2 / ap]

ap = ao/p

ap = 3000/15.875

ap = 188.97mm

where, ao- centre distance

ap- approximate centre distance in multiple of pitches

Number of links,

lp = 2 x 188.97 + [(30+30)/2]

lp = 407.94mm ≈ 410mm

lp = 410mm

Actual length = lp x p

Actual length = 410 x 15.875

Actual length = 6508.75mm ≈ 6510mm

4.10 CALCULATION OF ACTUAL CENTRE DISTANCE

Actual centre distance,

a = [(e * p) + √(e2 – 8m)] / 4

(z1 = z2 = 30)

So, m = 0

e = lp – [(z1 + z2/2)]

e = 410 – [(30 + 30)/2]47

e = 380

Actual centre distance, a = (380 x 15.875) + √(3802 – 8 x 0)

Actual centre distance, a = 3016.25mm ≈ 3020 mm

4.11 CALCULATION OF SPROCKET DIAMETER

Inner diameter of sprocket,

d = p/sin(180/z)

d = 15.875/(sin 180/30)

d = 151.87mm ≈ 152mm

d = 152mm

Roller diameter, Dr = 10.16mm

Outer diameter of sprocket,

D = d+ 0.8Dr

D = 152 + (0.8 x 0.16)

D = 160mm

Pitch angle,

α = 360/z

α = 360/30

α = 12o

Centrifugal tension,

Pc = mv2

Pc = 1.75 x 0.392

Pc = 0.28 kN

Pc = 28 N

4.12 CHAIN SLING CALCULATION

Safe Working load = 1800kg48

Safe Working Load, SWL = D2 x G x 0.3

where, G- grade 60 chain sling (alloy steel)

D- diameter

D2 x 60 x 0.3 = 1800

D2 = 1800/(60 x 0.3)

D2 = 55.56

D = √55.56

D = 7.76mm ≈ 8mm

Diameter of chain sling, D = 8mm

4.13 TABULATION:

Table 1.0 (Specifications of chain)

Table 1.1 (Load factor, k1)

49

Table 1.2 (Factor for distance regulation, k2)

Table 1.3 (Factor for centre distance of sprockets, k3)

50

Table 1.4 (Factor for position of sprockets, k4)

Table 1.6 (Lubrication factor, k5)

Table 1.7 (Rating factor, k6)

Table 2.0 (Factor of safety)51

PitchP,

mm

Speed of rotation of small sprocket, rpm

<50 200 400 600 800 1000 1200 1600 2000 2400 2800

9.52512.7

15.875

7.0 7.8 8.55 9.35 10.2 11.0 11.7 13.2 14.8 16.3 18.0

Pitchp, mm

Speed of rotation of small sprocket, rpm

<50 200 400 600 800 1000 1200 1600 2000 2400 2800

9.52512.7

15.875

35 31.5 28.7 26.2 24.2 22.4 21.0 18.5 16.5 15 13.7

Table 2.1 (Allowable Bearing Stress)

52

CHAPTER 5

WORKING

5.1 WORKING

In this technique, two sprockets (spr c and spr d) are additionally coupled

with the sprocket (a) and sprocket (b). The sprockets are coupled using shafts. The

sprockets (c) and (d) are linked with a chain drive (duplex chain). The ends of the

chain are attached with hooks, which is used to lift the hub. Due to heavy weight

at one side of hub, the lifting process becomes unbalance. When hub slides at the

right side of the tackling frame, the sprocket (c) and (d) will rotates at clockwise

direction. During this rotation, the power will be transmitted from sprocket (c) and

(d) to sprocket (a) and (b) respectively.

However, the rotation of sprocket (a) and (b) leads to move the disc plates

located at the cross bar of frame. When the disc plate moves through a certain

distance, the hub weight would be balanced.

5.2 ADVANTAGES

It will reduce the time consumption of work.

It improves work efficiency.

Less maintenance.

Self-balancing method performs the operation much faster than with manual

labour, this improves overall productivity.

53

Mechanical load brake assures braking even under overload conditions.

The design assures low headroom and this makes close trolley approaches

possible.

Hoist motor features aluminum alloy cast housing for optimal motor heat

dissipation and to reduce overall hoist weight.

Pushbutton pendant with emergency stop is durable, light weight and water

proof.

5.3FUTURE MODIFICATIONS

In future, the motorized trolley may be replaced into electromagnetic trolley

for better performance.

The electric motor lifting method may be replaced with hydraulic system to

save electrical energy.

Electromagnetic brakes may be installed in the travelling rail of trolley

instead of rubber stopper.

54

CHAPTER 6

CONCLUSION

Sometimes in our day-to-day life somewhere and sometime we will have the

need to carry a heavy load from one place to another. This happens more often in

various industries, particularly manufacturing industries. In rare instances we use

manpower or manual chain hoist, but when there is a constant need to do such

operations frequently and regularly then we need to think about an another option,

and that is self balancing lifting tackle.

On designing the self balanced lifting tackle which is driven by electrical

power, the reduction of time consumption of work, utilization of labour as well as

labour cost and increase in the production rate is achieved. Thus the working

efficiency as well as safety are ensured by this self balanced lifting tackle and is

successfully designed. It is easier and simple compared to the existing design. At

the same time the output is increased and the accuracy is maintained as the same.

The new design is flexible in design and can easily replace the conventional

design.

55

CHAPTER 7

REFERENCE

In the process of designing we went through several books and websites.

These are mentioned below:

7.1 BOOKS

Maitra G.M., Prasad L.V., “Hand book of Mechanical Design”, II Edition,

Tata McGraw-Hill, 2001.

Bhandari V.B., “Design of Machine Elements”, Tata McGraw-Hill

Publishing Company Ltd., 2004.

Hamrock B.J., Jacobson B., Schmid S.R., “Fundamentals of Machine

Elements”, McGraw-Hill Book Co., 2009

Ugural A.C., “Mechanical Design, An Integrated Approach”, McGraw-Hill,

2003

7.2 WEBSITES

www.firstgear.com

www.efunda.com

www.adamsmachinery.com

www.ansi.org

en.wikipedia.org

56