14 Examination Subject Code: 12256 Model Answer Page No

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MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 1/16 Important Instructions to examiners: 1) The answers should be examined by key words and not as word-to-word as given in the model answer scheme. 2) The model answer and the answer written by candidate may vary but the examiner may try to assess the understanding level of the candidate. 3) The language errors such as grammatical, spelling errors should not be given more importance. (Not applicable for subject English and Communication Skills). 4) While assessing figures, examiner may give credit for principal components indicated in the figure. The figures drawn by candidate and model answer may vary. The examiner may give credit for any equivalent figure drawn. 5) Credits may be given step wise for numerical problems. In some cases, the assumed constant values may vary and there may be some difference in the candidate’s answers and model answer. 6) In case of some questions credit may be given by judgment on part of examiner of relevant answer based on candidate’s understanding. 7) For programming language papers, credit may be given to any other program based on equivalent concept. Model Answer 1. a) Solve any three of the following. i) State general specifications of a typical earth moving machine. Answer: General specifications of a typical earth moving machine: (Any Four - 1 mark each) 1) Engine: Water-cooled, 4-cycle, direct injection, Turbocharged, and air-to-air after cooled. 2) Hydraulic systems: Closed-centre system with load sensing valves and pressure-compensated valves 3) Drives and brakes: Steering control - Two levers with pedals, Drive method - Fully Hydrostatic, Hydraulic motors –Variable displacement, axial piston motors, Maximum drawbar pull-56.4 kN 5750 kg, Maximum travel speed: High-4.5 km/h,Low-2.8 km/h, Service brake - Hydraulic lock, Parking brake - Hydraulic release lock 4) Swing system: Drive method - Hydraulic motor, Swing reduction - Planetary gear, Swing circle lubrication - Grease-bathed, Swing lock - Hydraulic lock. 5) Under carriage: Rack frame - Box-section, Shoe type - Triple grouser shoe, Track adjuster - Hydraulic 6) Coolant and lubrication capacity: Fuel tank -130 L, Coolant - 10 L, Engine – 5 to11.5 L, Final drive each side -1.1 L, Hydraulic tank - 61 L. 7) Operating weight: Up to 6580 kg 8) Lifting capacity: 1380 -1530kg. 9) Dimensions: Overall length- 6080 mm, Overall height (to top of boom) - 2500 mm, Overall width - 2225 mm, Ground clearance of counterweight - 750 mm. Marks 12 4 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 2/16 ii) Give applications of hoe and cranes. 4 Answer: Applications of hoe: (Any four – 1/2 mark each) 1) Digging and cleaning, irrigation ditches. 2) Land clearing. 3) Mining. 4) Road construction. 5) Railway bridge construction. 6) Railway route construction. 7) Pipe laying. Applications of cranes (Any four – 1/2 mark each) 1) It is used to lift a load in civil constructions and metal industries. 2) It is used to transfer the material from one place to another. 3) Bridge construction. 4) For towing purpose in case of breakdown of vehicle. iii) Explain blasting versus ripping applications of tractor dozer. Answer: Blasting versus ripping applications of tractor dozer (Any four points– 1 mark each) Sr. No. 1 2 3 Blasting Cost of blasting is 50 % more with the cost of drilling, blasting, loading with loaders and hauling with trucks. Blasting is used for hard rock. 4 Rocks which propagate sound waves at high velocities are drilled or blast. Cannot get definite size. 5 Blasting is hazardous. 2 2 4 Ripping Cost of ripping is 50 % less including ripping and hauling with scrapers. Ripper is used in old pavements, weak rock and bases. Rocks which propagate sound waves at low velocities are rippable. 4 Exact size is obtained during the use of rippers. Rippers operate safely. iv) State difference between loaders and excavators. Answer:(Any four points – 1 mark each) Sr. No. Loaders 1 Loaders may be both wheeled type and crawler type. 2 It is used for transportation of excavated material. 3 The attachments used are standard bucket , bulk handling bucket, fork lift attachment, crane attachment 4 speed is more as compared to excavator 5 Transportation cost is less because it can travel on road. 4 Excavators Excavators are only crawler type. Excavators are used for excavation purpose. The attachment used is ejector bucket, multipurpose bucket and digging bucket. Speed is less as compared to loader. Transportation cost is high because it need separate vehicle for its transportation. 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Summer – 14 EXAMINATION Model Answer Subject Code: 12256 Page No: 3/16 B) Solve any one of the following: 6 i) Compare between general automobile and earth moving machine on following parameters - Power output and power variations - Working conditions - Steering - RTO registration - Fuel and fuel consumptions - Brakes Answer: Comparison between general automobile and earth moving machine: Parameters 1. Power output and power variations 2. Working conditions 3. Steering General automobile Less power output, less power variations On road Wheel operated Earth moving machine More power output, more power variations Off road Lever operated 4. RTO registration On the basis of type of vehicle. Petrol or diesel, less fuel consumption Air/ hydraulic brakes On the basis of capacity 5. Fuel and fuel consumptions 6. Brakes Mostly Diesel, consumption hydraulic brakes more 6 6 fuel ii) Explain construction of scraper with the help of block diagram. Answer – Construction of Self Propeller Scraper: 6 3 Figure – Self Propeller Scraper The scraper is a combination of the best leading and handling machine. It is essential consists of a large scoop provided with a cutting edge. The scrap is in the form of bucket or a shallow container which is known as bowl or body. The scoop can excavate transport and dump the material where required. The cutting edge of the scoop does the excavating work and the excavated material goes on collecting in the scoop from its front gate. The material is transported to the sight of dumping and is taken out from the tail gate of the scoop. It is mounted on two or more pneumatic wheels and is pulled by a tractor. Thus a scraper is considered as a self sufficient machine. As it can do all the operations necessary for light soils i.e. we can excavate load, transport and dump the soil at required site. Apron is provided at the front of the bowl which opens and closes to regulate the flow of excavated material into the bowl. Note: Construction of Towed Scrapper with block diagram may be considered) 3 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Summer – 14 EXAMINATION Model Answer Subject Code: 12256 Page No: 4/16 2. Solve any four of the following: 16 i) Draw a typical layout of tractor dozer and state its applications. Answer: Typical layout of tractor dozer and its applications: 4 3 Fig. – Layout of Tractor Dozer Applications of tractor dozer - (Any two) 1) Shallow excavation or side hill cutting 2) Clearance of shrubs and small trees 3) Clearance of trees by using raised mould blade as pusher arm 4) Clearing the floors of borrows and quarry pits. 5) Backfilling of trenches. ii) Explain the role of earth moving machines in road laying and disaster management. Answer: Role of earth moving machine in road laying: 1) Crushing of the rocks. 2) Digging and pushing of the crush materials. 3) Transportation of the materials required for road construction. 4) To prepare the mixture required for road construction. 5) Levelling of the road. 6) Lifting the materials required. Role of earth moving machine in disaster management : 1) Dumping the excavated material to a required place during earth quick. 2) Cutting and removing trees which fall down on the road during storms to open the road. 3) To excavate the ice on the road during snow fall. 4) To rescue the people from the building during fire. 5) Levelling, spreading soil for road generation on war front. 1 4 2 2 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 5/16 iii) What is a clamshell? Explain construction with simple sketch. Answer: Clamshell: Clamshell is used to handle loose material such as sand, gravel, and crushed stone. They are specially suited for lifting material vertically. Construction of Clamshell: A clamshell consists of hoist drum lagging, clamshell bucket, tag line, and wire ropes to operate holding and closing lines. On some crane models, the hoist drum lagging (hoist drum diameter) can be changed to meet the speed or pull requirements for clamshell operations. Clamshell buckets are available in various sizes and in heavy duty types as digging medium weight types for general purpose work and lightweight types for re-handling light materials. The teeth are used in digging the harder type of materials but are not required when a bucket is used for re-handing purposes. The capacity of a clamshell bucket is usually given in cubic yards. 4 1 2 1 Figure: clamshell iv) Explain the importance of counter weight in forklift truck. Answer: Importance of counter weight in forklift truck: Counter weight is a mass attached to the rear of the forklift truck frame. The purpose of the counterweight is to counterbalance the load being lifted Forklifts are used for material handling. When a forklift raises a heavy object into the air, the rear of the forklift becomes very light, as the weight on the forks attempts to rotate the forklift over the front tires and it may loosen its stability and control. A counterweight is added on the rear to counter the tipping pressure on the front axle, thereby allowing the forklift to remain level. Counterweight increases the lifting capacity of the truck. In an electric forklift the large lead-acid battery itself may serve as part of the counterweight. 4 v) Describe safety arrangements in loaders and excavators. Answer: Safety arrangements in loaders and excavators: (Any four ) 1) Roll Over Protection System – Roll Over Protection Structure (ROPS) refers to operator compartment structures (usually cabs or frames) intended to protect equipment operators and motorists from injuries caused by vehicle overturns or rollovers. 2) Falling Object Protection System in cab protection - Falling Object Protection Systems are designed to protect the excavator cab and operator from falling objects in dangerous environments. 3) Rear-view camera – A rear view camera reduces operator blind spots and protects him 4 4 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 4) 5) 6) 7) Summer – 14 EXAMINATION Model Answer Page No: 6/16 better against a fatality. Comfort Drive Control (CDC) - Comfort Drive Control (CDC) system, which features an adjustable armrest that houses a small lever the operator moves with his fingers to steer the machine. This lessens the monotonous and strenuous turning of the steering wheel, reducing the risk of injury. Comfortable seats - ideal for long operator working shifts Restricted machine speed if operator door is open. Slip-protected and distinguished colourized platforms 3. Solve any four of the following: i) Explain the use of dragline in terms of excavating channels, shallow grading, loading and slopping. Answer: Use of dragline: 1. Excavating Channels: In excavating channels, dragline is used because it can dig and dump over longer distance than other types of shovels. 16 2. Shallow Grading: While shallow grading effective grade control is required and it is not achieved by using back-hoe machines therefore draglines are used. 1 3. Loading: In mining operations when excavation takes place, the excavated material is directly loaded to a dump truck by dragline itself without help of any loader. 1 4. Sloping: The draglines are designed to excavate material below the level of machine therefore in sloping operation draglines are used. 1 ii) Describe the various types of buckets and their applications for hydraulic excavators. Answer: Various types of buckets and their applications for hydraulic excavators: Types of hydraulic excavator buckets: 1) The Digging Bucket - The bucket is so constructed that it will not dump its content until the dragline tension is released. 2) Rock Bucket - To operate the rock bucket, the tines are submerged below the grade and object. When the bucket is raised back up, the object stays in the bucket while the loose material falls through the tines. The rock bucket effectively clears the soil surface of vegetation and other debris. It also pulls objects from below ground. 3) V Bucket - V-Ditching Buckets can be made for any size of excavator, and are extremely useful for forming and maintaining ditches. 4) Skeleton Bucket - Excellent for quarry work, design allows for sifting of loose debris to fall through to keep material load to minimum iii) Explain under carriage maintenance for dozers. 4 1 4 4 4 Answer: Under carriage maintenance for dozers: Under carriage maintenance of tractor dozer consists checking and lubrication of following components: 1) Track frame: Check the connections of the track frame and its lubrication. 2) Wheel and axle: Check bearings for wear and lubrication and axle bends 3) Sprockets: Check for teeth wear, if excessive wear, replace it. 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 7/16 4) Idler: Adjust tension and check for wear. 5) Spring cushion: If damaged, replace it. 6) Drive mechanism: Roller chains, roller chain pins, links and bushings: check for wear of chains, pins, bushings etc, if excessively worn out replace it. Adjust roller chains for tension. 7) Track shoes: Check wear. 8) Track rollers: Check for wear and lubrication. 9) Support rollers: Check for wear and lubrication. iv) State the importance of earth moving machinery in terms of infrastructure development. Answer: Importance of earth moving machinery in terms of infrastructure development : Infrastructure development is directly associated with the economy of the nation, earth moving machinery plays important role in the infrastructure development of the India like 1) Construction of bridges and highways 2) Build up of various types of industries 3) Constructions of the dams 4) Constructions of the power stations 5) Contribution in disaster management. 4 v) Draw the general layout of tractor. Answer: General layout of tractor: (Sketch -3 marks, label -1 mark) 4 4 4 vi) What is tipper? Explain the tipping mechanism. Answer: Tipper The tipper is used to carry the load from one place to another. Generally truck or load carriage carries load and it take long period for unloading. By the tipping operation in tippers, easy unloading is possible. 4 1 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 8/16 Tipping mechanism – Tipping mechanisms work basically on the following: Hydraulic cylinder: A hydraulic cylinder is placed below the body of truck longitudinally at one end of the truck, and the piston end of the hydraulic cylinder is connected by the means of a pivot joint to the chassis of truck. In the forward stroke of the cylinder, it pushes the truck body upward thus gives necessary lift for tipping dumping. So, in the forward stroke of the cylinder, the truck is unloaded. In the return stroke of the cylinder the body of the truck comes to its original position. Hinge Joint: The other bottom end of the body of the truck is connected by a hinged joint with the chassis. So, when the hydraulic cylinder pushes the body in it's forward stroke the entire body gets tilted about the axis of the hinged joint and the material gets unloaded and by the return stroke of the hydraulic cylinder body comes and seat to its original position with respect to the hinged axis. In this types of tipper can unload materials only at the backside of the tipper. 2 1 Figure - Tipping Mechanism (Note: Credit shall be given to any other equivalent line diagram ) 4 a) Solve any three of the following: i) Give the comparison of tractor with an automobile. Answer: Comparison of tractor with an automobile: (Any 4 points - 1 mark each ) Parameter 1. Working conditions 2. Working Speed 3. Applications 4. Fuel 5. PTO shaft 6. Tyres 7. Stability 8. Torque Tractor It is used in both on road and off road. Speed of tractor is low. It is used for special purpose work and agricultural work. Diesel is generally used. PTO shaft is available in tractor for different attachments or implements Special tyres are designed required for gripping purpose. Stability is most important during operation More torque is available. 12 4 Automobile It is used on road only. Speed is high. It is used for carrying goods and passengers. Petrol and diesel are used. It is not available in automobile. Traditional tyres are required. Stability is most important during driving Less torque is available. 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 9/16 ii) Explain track shoe construction and working. Answer: Construction and working of track shoe: It consists of engine mounted on the chassis and connected to clutch, gear box to driving sprocket. On the driving sprocket tracks is provided for transmitting power to the Idler sprocket. In this type of tractors, instead of wheel, track is fitted on either side. This tractor gets the drive from driving sprocket by the rear axle shaft. To steer the tractor levers are provided. The tractor is steered by applying the brake in one side of the rack with the other track is moving. 4 2 2 iii) Compare the tyred and crawler type earth moving machines. Answer : Comparison of tyred and crawler type earth moving machines: ( Any 4 points ) Sr.No 1 2 3 4 5 6 7 Tyred Good on firm soil and concrete and oppressive soils that have no sharp edges, pieces. Best for leveled and downhill work Wet weather causing soft and slip surface conditions will slow or stop operation. Good for long travel distance. Best in handling loose soil. Fast return speed 8 – 26 mph Can only handle moderate blade load 4 Crawler Can work on variety of soils Can work over almost any terrain Can work on soft ground and over muddy and slippery surface. Good for short work distance. Can handle tight soil Slow return speed 5 – 10 mph Can push large blade loads 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 10/16 iv) Draw a typical layout of a forklift truck and state its types. Answer: Typical layout of a forklift truck - 4 2 Figure Forklift truck Types of Forklift truck – A) Based upon the structure – 1) Standard truck 2) Reach truck 3) Order selector 4) Motorized pallet truck 5) Swing mast trucks 6) Turret trucks B) Based on medium used to run the forklifts – 1) Internal combustion forklifts 2) Electric forklifts B) Solve any one of the following: i) Explain the construction of tractor tyres and their selection. Answer : Construction of tractor tyre: It is traditional tyre. It encloses a tube in which air is forced to high pressure as a cushioning medium the outer panel of the tyre which roles on the road is made of synthetic rubber and its trade at the inner edges beads are found by reinforcing with steel wires. The beads act as strong shoulder for bearing against the wheel rim. Rayon cards are formed into a number of piles where the beads and cards give strength to the tyre. 2 6 6 2 2 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 11/16 Selection of Tractor tyre is based on following parameters (any four) : 1) Traction – it should have maximum traction as it is used for off road applications (loose sand) 2) Tyre tread depth - it should have maximum tyre tread depth in order to improve traction 3) Load carrying capacity - it should have maximum load carrying capacity. To improve load carrying capacity strong carcass ply-cord material is selected 4) Balancing- tyre must be statically as well as dynamically balanced 5) Tyre life – it should have maximum life 6) Wear resistance - tyre should have good wear resistance 7) Non skidding – tyre should have good antiskid properties ii) Draw the transmission layout of the tractor and explain power transmission. Answer: Transmission layout of the tractor: 2 6 4 Figure. Power train and transmission layout of tractor The tractor is fitted with a diesel engine which acts as a source of power to drive the tractor or it is a machine which converts fuel energy into mechanical energy. The clutch is used to transmit the power from engine to the gearbox. Main function of clutch is to connect and disconnect the engine drive to gear box. Gear box increase the driving torque to enable the tractor to pull more loads. Further power is transmitted from gearbox to the differential through the final drive. The final drive turns the power through 900 and transmits to the half axles. Reduction gears are fitted on the half axles which helps the tractor to take turn. 5. Solve any FOUR of the following. i) Explain how the earth moving machines are classified? Any four criteria. Answer: Classification of earth moving machines: 1) On the basis of nature of work – a. Excavation machines b. Compacting machines c. Material handling equipments 2 16 4 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 12/16 2) On the basis of control – a. Cable controlled b. Hydraulically controlled c. Electrically controlled 3) On the basis of mounting – a. Wheel mounted b. Crawler mounted 4) On the basis of area of work – a. On road b. Off Road ii) Describe the construction of motor grader with neat sketch. 4 Answer: Construction of motor grader: 2 Construction of motor grader It consists - Tractor or engine, articulated carriage, blade, tilting frame, lifting and tilting cylinders. It has engine up to 300 hp and are provided with hydraulically controlled attachments, these attachments include an excavation blade similar to the bull dozer, scarifier, ripper and backhoe. The blade of motor grader has replaceable cutting edges. These blades coming flat, curve and serrated styles. Motor graders are fitted with articulated frames for increasing manoeuvrability. iii) What are the different types of dozer blades? Explain with neat sketch. Answer: Different types of dozer blades: ( Any two types with neat sketch – 2 marks each ) 1) Straight blade – In straight dozer, blade is attached exact perpendicular to direction of motion. A straight blade that is short and has no lateral curve, no side wings. The dozer is equipped with a diesel engine and is supported on the ground by a track assembly. 2) Angle blade – An angle blade is wider by 1-2 feet than an s blade. It can be angled up to 250 left or right of perpendicular to the dozer. It is use for side casting material for backfilling or making side hill cuts. 3) Universal blade – This blade is wider than a s blade and outside edges are canted forward about 250. It is used for stock piles and drifting loose or non cohesive materials. 4) Cushion blade – Cushion blades are mounted on large dozer that is used primarily for push loading scrapers. 2 4 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 13/16 ( Credit shall be given to any other equivalent line diagram ) iv) State any four differences between power tillers and tractors. Answer: Difference between power tillers and tractors: (Any four) Parameters 1. Size 2. Wheels 3. Power 4. Weight 5. Operation Power tiller it is small size tractor Small two wheels are required Less power developed Weight of the tiller is less It is operated by handle Tractor it is big size tractor More wheels are required More power developed Weight of tractor is more It is self propelled vehicle v) Draw a typical layout of a road roller and state its applications. Answer: Typical layout of a road roller: 4 4 4 3 Figure: Layout of Road Roller MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 14/16 Applications of road roller: (Any two) 1) For compacting thick layers of road material in road construction. 2) For compacting bituminous concentrated layers in roads. 3) For consolidation of stone, soil, sand and surface dressing. 4) For leveling of ground. vi) Enlist various safety precautions in terms of forklift operations. Answer: Safety precautions in terms of forklift operations: ( Note: Any four points) 1) Forklift will be kept control at all times. 2) Forklift will not be fixed object, such as a wall or bench. 3) Standing or passing under the elevated portion of a truck, whether loaded or empty is prohibited. 4) Person other than the operator will not be permitted to ride on the fork-lift truck. 5) Arms and legs must be kept within the running lines of the truck and out from between the right of the most. 6) When changing fuel tanks, the operator is required to wear gloves for protection against the possibility of exposure. 7) All hazardous conditions within the flow of traffic such as oil spills, water, and paddles should be immediately cleaned up. 6. Solve any four of the following i) Compare the hinge and parallelogram type rippers. 1 4 4 16 4 Answer: Comparison of hinge and parallelogram type rippers. Sr.No. Parallelogram rippers 1 Straight shanks are used for massive or blocky formation. 2 This type of attachment is used generally in tough materials. 3 Ripper maintains the shank in vertical position and keeps the teeth at an constant angle 4 The shank is not used for drilling purpose Hinge rippers Curved shanks are used for bedded or laminated rocks for pavements. It is not used for tough materials. 4 The angle of teeth attack varies with the depth the shank is depressed. The shank is used for drilling purpose ii) Describe various types of wheeled loaders. Answer: Types of wheeled loaders : 1) Front hoe loader : A loader is a type of tractor usually wheeled sometime on track that has a front mounted square wide bucket connected to the end of two booms (arms) to scoop up loose material from the ground such from one place to another without pushing the material across the ground. A loaders is commonly used to move a stock coil material from ground level and deposits it into an awaiting dump truck on into an open trench excavation The booms are opened through the hydraulic power by piston and cylinder arrangement. At the end of boom bucket is attached with the hinge which is operated by hydraulic way and it can be lift to the position. 2) Back hoe loader : A back hoe loaders also called back hoe digger. The backhoe is a heavy equipped vehicle that consists of tractor fitted with a shovel or bucket in the front and a small backhoe on the back. 4 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer Page No: 15/16 Due to its small size and versatility backhoe loaders are very common in urban region and small constructions projects. The back hoe loaders consist of boom stick cylinder, bucket. There are 3 hydraulic cylinders and piston arrangement for operating boom, Stick and bucket ram. Bucket can be lift with the help of hinge at the end of stick and at the last a boom is swivel to any particular direction with the swiveling arm. iii) Explain the use of various types of implements in a tractor. Answer: Use of various types of implements in a tractor Implements are used in tractor for performing the various operations by different implements such as agricultural implements. Agricultural implements are of two types – 1) Primary tillage – It is used for breaking the soil; after the soil has been broken it is used for side bed preparation. It also used for cleaning of land, for covering vegetables and green crop. 2) Secondary tillage – This type of tillage is used for preparing the soil, smoothing and packing the soil. It is also used for loosen the soil, cut the crop residue. The above function is worked by following implements – a) Disc narrow b) Tooth narrow c) Pulverizer and rollers d) Cultivators iv) State two applications of each in construction industry – forklift truck, tipper and road roller. Answer: Applications of forklift truck – 1) They can be used to transport heavy building materials over fairly long distances, across rough terrain. 2) Forklifts can unload pallets of bricks, steel girders and other construction products from the delivery truck and carry them to parts of the construction site that are not accessible to other vehicles. Applications of Tipper – 1) Tippers are used for the transport of all materials in road construction from road-site to dump and burrow or plant to road-site. 2) In dams, hydropower projects and canal work, nature of work involved is essentially removal and relocation of earth on the sites to obtain the desired profile. This earth movement is done again largely by tippers. Applications of Road roller (any two) – 1) For compacting thick layers of road material in road construction. 2) For compacting bituminous concentrated layers in roads. 3) For bridge construction. 4 4 4 4 MAHARASHTRA STATE BOARD OF TECHNICAL EDUCATION (Autonomous) (ISO/IEC - 27001 - 2005 Certified) Subject Code: 12256 Summer – 14 EXAMINATION Model Answer v) Draw simple sketches of following dragline operations – - Excavating underwater soil - Excavating trenches Answer: Page No: 16/16 4 2 OR Figure - Excavating underwater soil 2 Figure -Excavating trenches