Agricultural Tractor Lesson 3 PDF

AGRICULTURAL TRACTOR ABE POWER 313 – AB POWER ENGINEERING DEFINITION OF TRACTOR ▪ self-propelled, wheeled vehicle having two axles designed to carry, pull or propel agricultural implements and machines ▪ an engineering vehicle specifically designed to deliver a high tractive effort (or torque...

AGRICULTURAL TRACTOR ABE POWER 313 – AB POWER ENGINEERING DEFINITION OF TRACTOR ▪ self-propelled, wheeled vehicle having two axles designed to carry, pull or propel agricultural implements and machines ▪ an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purpose of hauling a trailer or a machinery used in agriculture. ▪ A versatile machine and a mobile power source for wide variety of agricultural task. ▪ A machine that can deliver both stationary and mobile jobs. ▪ A machine that can pull or tow implement through traction from the drive wheel and or pull implement through the draft developed from its drawbar hitch or power implement through it PTO drive.  FUNCTIONS OF TRACTORS ▪ Pulling machine behind it; ▪ Pushing machine in front of it; ▪ Operating machine mounted on it; ▪ Transmitting power to other machines through the PTO drive; ▪ Raising, lowering, and controlling machines and attachment by its hydraulic power; ▪ Driving machines through belt power; ▪ Transmitting power through flexible shaft; and ▪ Furnishing power for fast highway transportation and handling. CLASSIFICATION TWO-WHEEL DRIVE FOUR-WHEEL DRIVE - type of four-wheel tractor where power is - type of four-wheel tractor where power is transmitted to rear wheels with small front transmitted to all wheels wheels being pushed along TYPES OF STEERING DESPCRIPTION OF AGRICULTURAL TRACTORS  Compact Tractor–A four-wheel tractor of less than 20 hp. It is used for landscaping and gardening rather than for massive agricultural tasks. It is equipped with single 12-in moldboard plow and is capable to plow 1 hectare within 11 to 14 hours.  Farm Tractor –A four-wheel tractor with no less than 20 brake horsepower. It is used for massive agricultural tasks such as plowing, harrowing, seeding and planting, and other operations. Special Type Tractors  Tract-type Tractor All Purpose or Row Crop Tractor –It is designed to handle field –It consists mainly of two heavy-duty endless link device known as tract for traction and belt jobs, including planting purposes. It is used for heavy duty operations and inter-tillage activities. such as earth moving and other industrial jobs requiring higher power.  Orchard Tractor –It is small and medium size and is designed to be operated with advantages under trees. It is built with lower and fewer projecting parts and has fenders for protection purposes.  Industrial Tractor –It is a machine of any size designed for various industrial operations and heavy hauling. It has hoisting, excavating, and/or power-loading attachments. PARTS OF A TRACTOR  BASIC PARTS OF A FOUR-WHEEL TRACTOR CANOPY STEERING WHEEL ROPS HOOD HEAD LIGHT SIGNAL LIGHTS BALLAST DRIVER SEAT FRONT WHEEL REAR WHEEL IMPLEMENT Typical controls of four-wheel tractor PERFORM A PRE-START SAFETY CHECK ON A TRACTOR PERFORM A PRE-START SAFETY CHECK ON A TRACTOR Walk around the tractor and look for any problems  Check that safety guards are in place.  Check for loose or damaged parts, such as nuts and bolts.  Check the drawbar and three-point linkage security.  Check for oil, fuel or water leaks from pipes and hoses.  Check the tire treads. PERFORM A PRE-START SAFETY CHECK ON A TRACTOR Check Brakes -Must be within the required value of 3.5cm Check Clutch -Should be 4-5cm PERFORM A PRE-START SAFETY CHECK ON A TRACTOR Check Oil Level  Must be standing on level ground  Allow approximately 10 minutes after the engine has stopped for the oil to drain down into the sump. Dipstick remove the dipstick, wipe it with rag and return it to the filler. PERFORM A PRE-START SAFETY CHECK ON A TRACTOR Cooling System Check the radiator, coolant tank, cooling fins, fans and air ducts.  Use a cloth to remove the cap and inspect when the engine is cool. PERFORM A PRE-START SAFETY CHECK ON A TRACTOR Battery Check and Maintain the Battery Terminals, Tightness and Dirt. PERFORM A PRE-START SAFETY CHECK ON A TRACTOR Air cleaner (Dry Type)  Periodically clean with blast of compressed air Air cleaner (Oil Bath Type)  Loosen the oil bath and remove it from the air cleaner body.  Replace the oil bath (and screen tray if used) and tighten clamp. PERFORM A PRE-START SAFETY CHECK ON A TRACTOR Drawbar and three-point linkage security. Check tyre treads, check tyre walls for cracks, tears and uneven wear or embedded pieces of steel or timber. Lubricate and Grease Fittings  Refer to the manufacturer’s timetable; a daily service grease TRACTOR SAFETY PTO Shield  Keep articles of clothing or hair or anything like that from getting tangled in the PTO shaft when it's turning. Roll-Over Protection Structure or ROPS Protect you in the event of an overturn. An important part of that is the seatbelt. TRACTOR SAFETY Clutch safety switch or starter interlock  Will not allow the starter to engage unless you have the clutch pedal fully depressed. Note: make sure all the levers are in neutral position for safety Implements  Keep as low as possible to avoid imbalance and overturn Ballast/ Counterweight ATTACH AND REMOVE A TRAILED IMPLEMENT ON A TRACTOR  Adjust the drawbar and the implement. Use jack stand.  Position tractor until the drawbar and the implement hitch hole(s) line up. Make sure engine is off and in parking brake Place the draw bar pin through the holes and secure with locking device CONNECT REMOTE HYDRAULICS Note: Some units do not have this feature  Drive the tractor and implement to a firm, level and well drained site.  Lower all hydraulically operated components  Disconnect the hoses in turn and stow them away from dust and water.  Ensure that connections and dust caps are absolutely clean and replace the dust caps as soon as each hose is disconnected.  Make sure the hoses are not kinked or twisted when stowed. ATTACH AND REMOVE A PTO SHAFT  Make sure that the parking brake, disengage the PTO drive then put the tractor in neutral or park.  Attach the implement (Three-point link or trailed)  Connect the Crossjoint and powershaft  Ensure that the implement is level and adjusted for safe, efficient operation.  CHECK THE COUPLING  Check the coupling of the powershaft to make sure it has the same number of splines or grooves: -540 rpm stub shaft has 6 splines. -1000 rpm stub shaft has 21 splines.  If the tractor has a high speed (1000 rpm) and low speed (540 rpm) PTO, use the correct one to suit the implement to be operated. CHECK THE POWERSHAFT AND SPRING-LOADED LOCK Powershaft Check that when it is fully extended, Make sure that the sliding shaft does not bottom out when the shafts are fully compressed Check that the two halves of the PTO shaft Spring Loaded Lock  Ensure the tractor is turned off  slide the powershaft onto the stubshaft until resistance is felt.  depress the pin pin.  Push the shaft forward and the locking mechanism will snap and lock  Try to move the powershaft back and forth  Always check that the locking mechanism THREE-POINT LINKAGE IMPLEMENT  To attach three-point linkage implement 1 3 4 2 THREE-POINT LINKAGE IMPLEMENT  To detach three-point linkage implement 4 3 1 2 Additional Readings  PAES 104 for the Type, Location and Operation of Controls for Agricultural Tractors  PAES 118 Specification of Four-Wheel Tractor  PAES 119 Method of Test of Four-Wheel Tractor TRACTOR BRAND & MAKE TRACTOR TERMINOLOGIES ▪ Drawbar - bar at the rear of a tractor to which implements are hitched ▪ drawbar power - power available at the drawbar sustainable over a distance of at least 20 meters ▪ power-take-off (PTO) shaft - external shaft usually at the rear of the tractor providing rotational power to implements and machines ▪ PTO output power - power measured at the PTO shaft ▪ roll-over protective structure (ROPS) - two- or four-post structural frames primarily used to protect a seat-belted operator from being crushed in case the machine rolls over ▪ three-point linkage - combination of one upper link and two lower links, each articulated to the tractor and the implement at opposite ends in order to connect the implement to the tractor TRACTOR TERMINOLOGIES ❑ Ballast: An added weight that serves as a counter balance for a heavy load, such as one you're carrying in your FEL. It is usually found in the rear of the tractor. ❑ Chassis: The framework that supports the tractor frame and guts including the engine, transmission, suspension, etc. ❑ Fast Hitch or Quick Hitch: The quick hitch is attached to the tractor 3-point hitch allowing the operator to easily hook onto implements, without leaving the tractor seat. ❑ FEL(Front-end Loader):A large bucket-like implement attached to the front of the tractor to lift materials such as rocks, dirt, etc. ❑ Synchronized Transmission: Allows for the shifting of gears on the move without the gears clashing. ❑ Transmission: A system of gears that determines the speed and direction of a tractor. Classifications of Hitch System and Controls 1. Drawbar hitch type - for large, heavy implement or trailers a. fixed type b. swinging drawbar c. link drawbar 2. Semi-mounted type - for planter, cultivator, etc. 3. Direct mounted or integral type - three point hitch system 4. Direct connected type - for rotary tiller Tractor Power Tractors deliver power in several ways. ▪ Pulled or towed implements are powered through the traction of drive wheels and the pull or draft from the drawbar. ▪ Rotary power is obtained from the power-take-off (PTO) shaft or from a belt pulley. ▪ Both linear and rotary power can be produced by a tractor’s hydraulic system ▪ Some implements require electric power from tractors. POWER PERFORMANCE o Drawbar power = 0.75 to 0.81 * net engine power = 0.92 to 0.93 * axle power = 0.86 to 0.89 * power take-off power o Power take off power = 0.87 to 0.90 * net engine power = 0.90 to 0.92 * transmission power Note: constants are the mechanical efficiency POWER PERFORMANCE o Axle power = 0.85 to 0.89 * transmission power = 0.94 to 0.96 * power take off power o Transmission power = 0.96 to 0.98 * net engine power Note: constants are the mechanical efficiency Functions of Power Transmission a. It is used to transmit the engine power to the wheel axle and to the PTO shaft of a tractor b. It is also used to change the torque and the speed of the engine tractor into high torque and low speed required by the wheel axle and by the PTO shaft.  Clutch–It is a device used to connect and disconnect the tractor engine from the power train so that the gear can be shifted or the tractor can be stop without stopping the engine. Differential –It is a special arrangement of gears so that it will permit one driving member to rotate slower or faster than the other and permit operation of driving wheels at different speed. Final Drive–It is a gear reduction mechanism located in the power train between the differential and the driving wheels used to transmit the power of the engine at low speed and large torque to the rear axle and wheels of the tractor. POWER TAKE-OFF SHAFT (PTO) - used for driving field machines such as rotary tiller, hay baler, corn picker, and in stationary position such as self-unloading forage wagon, irrigation pumps and others PTO STANDARDS PTO Shaft Speed Spline Shaft Number of Splines (Rpm) Diameter (mm) 540 35 6 1000 35 21 1000 45 20 Drawbar Pull It is one of the most important factors in the performance of a tractor. Plowing and other operations are affected by the drawbar performance of the tractor. Drawbar pull is affected by the wheel slip and the engine power. It is also affected by the tractor weight and type, the type and shape of the running gears or wheel condition of the ground surface, inflation pressure of tires and others. Coefficient of traction ranged from 32-75% depending on the condition of the ground while wheel slip ranged from 5 to 16% Tractor Size Tractor size can be determined based on the following: ▪ Weight–The heavier the tractor the bigger is its capacity. ▪ Horsepower –The higher the tractor horsepower, the bigger is its size and the more it is capable of doing wider operations. ▪ Implement Capacity–The more the tractor can draw implement, the bigger is its size and the faster it can finish the operation. Tractor size determination The primary tillage operation such as plowing and harrowing demand the highest draft requirements so that the initial estimation of tractor size is usually based on them. Ways to estimate the tractor size. 1. Use of specific draft Unit draft – is defined as the specific resistance of a given type of soil at a given moisture content to allow the passage of a given tillage implement. It is expressed in force per unit area (psi or kg/cm2). Table 1 shows the unit draft offered by different soil types. Unit draft of different soils Type of soil Unit draft Type of soil Unit draft (psi) (psi) 1. Sandy soil 3 5. Silt loam, dry 6-7 2. Sandy loan, moist 3-4 6. Clay loam, moist 6-7 3. Sandy loam, dry 4-6 7. Clay loam, dry 7-8 4. Silt loam, moist 5-6 8. Heavy clay 10-11 The steps for initial estimation of tractor size are as follows: a. Determine the unit draft of the soil. b. Calculation the draft offered by the implement c. Calculation the horsepower requirement d. Estimate the tractor size 2. Use of Specific Implement Resistance Several tillage implements offer specific resistance to agricultural soils Tables are also provided for such values of resistance. The procedure is the same as above. Specific resistance offered by various farm machines Operation Machine Specific resistance Tillage Chisel plow 200-800 lb/ft Subsoiler 70-160 lb/in depth/bottom Rotary tiller 5-10 PTOhp/ft Cultivation Rotary hoe 30-100 lb/ft Shallow row crop cultivator 40-80 lb/ft Chemical application Anhydrous ammonia applicator 420 lb/knife Planting Corn planter 80-120 lb/row Corn, soybeans, or cotton-drilling, all 250-450 lb/row attachment Harvesting Mower only 1 dhp/ft; 0.5 PTOhp/ft