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Loader
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 loader's 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 2 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 same axis, 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 snowbasket, 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.
The following we will introduce Carter 938G Series II Wheel Loader.
Engine
The 938G II provides more power, excellent fuel economy, and reduced maintenance.
Turbocharged, ATAAC. Turbocharging packs dense air into the cylinders for more complete combustion and lower emissions. Air-to-air aftercooling (ATAAC) provides a separate cooling system for intake manifold air. The ATAAC system reduces smoke and emissions by providingcooler inlet air for more efficient combustion.
Constant Net Horsepower. The 938G II’s electronic engine is integrated with an on-demand cooling fan. The engine compensates for varying fan loads and provides constant net horsepower, regardless of operating conditions. A consistent level of “working” horsepower is provided and fuel consumption is reduced.
Oil Change Intervals. The engine oil change interval is increased to
500 hours (with CH-4 oil), reducing costs and downtime
Powerful Performance. The 3126B ATAAC engine delivers net power of 119 kW (160 hp), and meets EPA Tier 2 emissions standards. Its advanced system keeps fuel at low pressure in the fuel lines until it is injected into the cylinder. Fuel pressure is created hydraulically in response to a signal from the ADEM III™ Electronic Control Module.
Electronic Control Module. The Advanced Diesel Engine Module (ADEM III) fuel system is
a proprietary electronic control module, which provides improved engine response and fuel efficiency,plus advanced diagnostics and reduced emissions. Altitude capability is increased to 3050 meters (10,000 feet) without derating. ADEM III allows full electronic integration
of the engine and transmission for maximum power train efficiency.
Power Train
Advanced Caterpillar power train is reliable and fuel efficient.Electronic Power Shift Transmission.The electronic power shift transmission with automatic shift capability is a countershaft design built by Caterpillar. It is electronically controlled and allows full power shifts and directional changes. Fully modulated gear shifts contribute to operator comfort and increase component life.Electronic Clutch Pressure Control (ECPC). Senses input from both the transmission and the operator controls in the cab to modulate each individual clutch through a proportional electro-hydraulic valve. This results in smoother gear changes and improved shift quality. Energy is modulated into the clutches, resulting in longer clutch life.
Integrated Braking System. New for G Series II, IBS integrates downshifting and transmission neutralization into the left-hand brake pedal. IBS provides smooth, optimized transmission neutralizer performance with a greater range of adjustability. The Integrated Braking System also lowers owning and operating costs by reducing axle oil temperatures, which can extend service brake life.Easy Service. Daily transmission oil level check is done from the ground through a well-protected sight gauge.An oil sampling valve allows quick,clean access to the transmission for S•O•SSM oil analysis.
Cooling System
New G Series II cooling package reduces radiator plugging and improves fuel efficiency.
Reverse Flow. Air enters through the rear grill and exits out the top opening and side hood doors. Rear air flow picks up less debris from the ground, reducing plugging.
Improved System Access. The 938G II adds a swing-out grill, hydraulic oil cooler and air conditioner condenser for easier cleaning. Side panels open to allow access to both sides of all cores for cleaning. A heavy duty Airborne Debris Grill, with 4 mm perforations is available as an attachment.
On-Demand Fan. Electronically controlled, variable speed on-demand fan adjusts to meet the varying cooling requirements of the machine. Fan speed is determined by oil, coolant and inlet
manifold temperatures. In cooler operating conditions, average fan speed is reduced, resulting in less fuel consumption, lower noise levels and less radiator plugging.
Unit Core Radiator. New unit core radiator with square wave shaped fins.Lower fin density (6 fins per inch) allows debris to pass through more easily.
Environmental Features
Caterpillar cares about the environment and continues to develop innovative solutions.
Low Exhaust Emissions. The Cat 3126B ATAAC engine used in the 938G Series II is a low emission engine designed to meet Tier 2 emission regulations. It is electronically controlled, with air-to-air aftercooling for more efficient combustion and cleaner emissions.
Reduced Sound. The electronic on-demand fan automatically
regulates fan speed depending on cooling requirements. The fan draws less horsepower in cooler ambient temperatures, which reduces fuel consumption. Sound levels are also reduced when the fan slows down.There is additional insulation around the engine to reduce sound levels.
Environmental Fluids. Extended Life Coolant/Antifreeze with anti-foaming and anti-corrosion properties provide extended service intervals (up to 6000 hours) and requires less frequent fluid changes and disposals. Air conditioning refrigerant is CFC-free.
Operator Station
The ultimate in wheel loader operator comfort and efficiency.
1 Steering. Low effort hand metering unit steering. Tilt steering column helps fit the wheel to the operator. Load sensing steering directs power through the steering system only when needed. When not steering, more engine power is available to generate rimpull, breakout and lift forces.
2 Excellent Visibility. The front window provides remarkable forward and peripheral
viewing, including the machine wheels and bucket corners. Bonded glass in the windshield eliminates frame obstructions.The sloping hood provides excellent visibility to the rear of the machine.
3 Finger Tip Controls. New pilot-assisted hydraulic implement controls deliver comfortable, low-effort operation. Single lever joystick and lift lever F-N-R switch are available as attachments.
4 New Instrument Cluster. Gauges, status indicators and alert indicators are now centrally located. 3-level warning system monitors key functions. The system alerts the operator of immediate or impending problems with engine oil pressure, parking brake, fuel pressure,electrical system, brake oil pressure,hydraulic oil temperature, transmission filter bypass, engine inlet manifold temperature, primary steering oil pressure and the air inlet heater. LED warning indicators with no bulbs to replace.
5 Cab Access. Left and right side doors swing open 180 degrees and latch for optimal ventilation, visibility and communication to ground level. Left and right side sliding windows are available as an attachment. Full service platforms are provided on both sides of the machine for safety and easy maintenance access.
6 Floor Mounted Pedals. All pedals including the new electronic governor,are floor mounted for greater operator comfort. Left pedal incorporates the new Integrated Braking System that combines service brake, transmission neutralizer and downshift functions.
7 Generous Storage Space.Compartments for lunchbox, coolers
and cups.
8 Seat Options. The standard cloth and vinyl seat adjusts 6 ways. A new Caterpillar Contour
air suspension seat (attachment) provides increased operator comfort with 6-way adjustment and automotive-style lumbar support.
9 Electronic Autoshift Control. Set for manual or one of two fully automatic shifting modes.
10 Ride Control System Switch.Attachment that reduces fore and aft pitch for a smoother, more comfortable ride. Allows the selection of three different modes: Off – always off service. On – always in service.Auto – the system is automatically actuated when the
machine travels at a speed greater than 9 km (6 mph).
11 Transmission Neutralizer Lockout Switch. Rocker switch that locks out the neutralizer. Defaults back to neutralizer “on” upon machine start up.
