LoadersOverviewBasic Concept .A loader is a type of construction equipment (engineering vehicle) machinery that is primarily used to load material into another type of machinery (dump truck, conveyor belt, rail-car, etc.).Loaders are used mainly for uploading materials into trucks, laying pipe, clearing rubble, and digging. A loader is not the most efficient machine for digging as it cannot dig very deep below the level of its wheels, like a backhoe can. Their deep bucket can usually store about 3-6 cubic meters of earth. The front loaders bucket capacity is much bigger than a bucket capacity of a backhoe loader. Loaders are not classified as earthmoving machinery, as their primary purpose is other than earthmoving.Unlike most bulldozers, most loaders are wheeled and not tracked, although track loaders are common. They are successful where sharp edged materials in construction debris would damage rubber wheels, or where the ground is soft and muddy. Wheels provide better mobility and speed and do not damage paved roads as much as tracks but provide less traction.Unlike standard tractors fitted with a front bucket, many large loaders do not use automotive steering mechanisms. Instead, they steer by a hydraulically actuated pivot point set exactly between the front and rear axles. This is referred to as articulated steering and allows the front axle to be solid, allowing it to carry greater weight. Articulated steering provides better maneuverability for a given wheelbase. Since the front wheels and attachment rotate on the sameaxis, the operator is able to steer his load in an arc after positioning the machine, which can be useful. The loader assembly may be a removable attachment or permanently mounted. Often the bucket can be replaced with other devices or tools-for example, many can mount forks to lift heavy pallets or shipping containers, and a hydraulically-opening clamshell bucket allows a loader to act as a light dozer or scraper.In construction areas loaders are also used to transport building materials - such as bricks, pipe, metal bars, and digging tools - over short distances. Loaders are also used for snow removal, using their bucket or a snow basket, but usually using a snowplow attachment. They clear snow from streets, highways and parking lots. They sometimes load snow into dump trucks for transport.Front loaders gained popularity during the last two decades, especially in urban engineering projects and small earthmoving works. Many engineering vehicle manufacturers offer a wide range of loaders, the most notable are those of John Deere, Caterpillar, Case, Volvo, Komatsu and Liebherr.Hydro mechanical Transmission System1.engine；2. torque converter；3. power shifting transmission box；4. front axle；5. Caliper disc brake；6. wheel；7. parking brake；8. rear axle；9. gear shift pump；10. steering pump；11. operational pump；12. wheel redactorTransmission System Arrangement1. engine；2. torque converter；3. power shift transmission box；4. rear frame；5. front frame；6. front axle；7. transmission shaft；8. rear axleTorque Converter1. flywheel；2、4、7、11、17、19. bearing；3. torque converter rotation housing；5. elastic plate；6. first turbine； 8. second turbine；9. stator；10. pump impeller；12. gear；13. stator shaft；14. second turbine shaft；15. first turbine shaft；16. spacer ring；18. one-way clutch gear；20. one-way clutch rollerPerformance CharacteristicHydro-mechanical Series Drive1. engine；2. piston pump；3. low speed piston motor；4.high peed piston motor；5. transfer caseHastate Power Train System1. Neutral-start parking brake lever；2. Track motors；3. Hastate pumps hoses；4. Hydraulic oil cooler；5. Service brakes；6. hoses；7. Wet, multi-disc parking brakes；8. Double reduction planetary final drives；9. hydraulic filtersStandard Equipment Specifications4. Brakes：Service brakes: Hydraulically-actuated, wet disc brakes actuateon four wheels：Parking brake: Wet, multi-disc brake on transmission output shaft5. Steering System：Type：Articulated type, full-hydraulic power steering；Steering angle：40 each direction;Minimum turning radius at the center of outside tire 。7. Bucket Controls：The use of a PPC hydraulic control valve offers lighter operating effort for the work equipment control levers. The reduction in the lever force and travel makes it easy to operate in the work envy- ornament.Control positions：Boom：Raise, hold, lower, and float；Bucket ：Roll back, hold, and dump8. Hydraulic System：Capacity (discharge flow) engine-rated rpm：Loader pump；Steering pump；Pilot pump(Gear-type pumps)；Relief valve setting；Control valve：2-spool open center type；Hydraulic cylinders：Double-acting, piston；Hydraulic cycle time (rated load in bucket)：Raise，Dump，Lower (empty)，Total cycle time1. The round-back bucket design is stronger with no angled corners. This configuration makes it easier to fill and dump improving productivity.2. The ROPS/FOP