Cat's latest materials handlers, introduced at this year's ISRI 2013 in Orlando, are the models MH3049 and MH3059. The new models' design is focused on operator safety, structural strength, hydraulic power, fuel efficiency and serviceability.
With an operating weight of 111,000 pounds (50,349 kg), the MH3049 is the first of several new wheeled material handlers that Caterpillar will introduce in the greater-than-25-tons class. Coming immediately behind the MH3049 is the new MH3059 at an operating weight of 130,000 pounds (58,967 kg). The new Cat material handlers are purpose-built to work productively and durably in industrial, scrap recycling, and waterway applications, while affording maximum protection and convenience for the operator. A patented “ground entry and exit” with a step-in cab enhances safety for operators and service personnel.
Both of the new material handlers are powered by the Cat ACERT C9 8.8L engine featuring an electronically controlled, mechanically actuated, unit-injector fuel system that uses multiple-injection fuel delivery for optimum power and economy in all operating situations. The MH3049's C9 engine is rated at 300-horsepower (224 kW) while the MH3059 engine is rated at 325 hp (242 kW).
High strength structural steel and advanced welding techniques ensure structural integrity; a powerful hydraulic system provides rapid response with efficiency; a Cat C9 ACERT™ engine delivers reliable, fuel-saving performance; and new serviceability features simplify maintenance. These design elements combine to provide low-cost operation and maximum value for the MH3049 and MH3059 customers.
Structures and hydraulics
Major structures use continuous welds that incorporate extensive chamfering and beveling to reduce stress concentration. Both the booms and sticks are constructed from single piece top and side steel plates eliminating the need for seams and internal baffles. The upper frame is designed specifically to dissipate loads transferred through the front linkage and counterweight, and the lower frame's unique tapered design evenly distributes loads and reduces stress. Oversized pins and bushings strengthen pivot points. In addition, extensive finite element analysis and strain-gauge testing throughout the design process ensure long-term durability.
Using a closed-center, two-pump, load-sensing implement hydraulic system with electro-hydraulic pilot control, hydraulic pumps generate only as much oil flow and pressure as required for the application, yielding powerful, rapid response and fuel-saving efficiency. To further enhance overall hydraulic power and efficiency, the machines regenerate boom-down oil flow, reducing the volume of oil the pumps must produce.
Reflecting the precise hydraulic design, the machines divide hydraulic functions between the upper and lower main control valves, with the upper valve managing the boom, stick, work tools, cab riser, and cooling circuits, and the lower valve controlling travel, steering, and outriggers. This provides optimal flow management to allow multiple machine functions to occur at the same time without compromising performance. An independent closed loop swing system maintains swing priority at all time. The hydraulic-oil cooler, working with an auto-reversing fan, is positioned away from the independent engine cooling system to ensure optimum operating temperatures between 140F and 160F (60-71C), which protects oil quality, extends component life, and promotes optimum machine performance.
Operator safety and convenience
The hydraulic cab-riser system features patented “ground entry and exit" with a step-in cab, enhancing safety for operators and service personnel. Cab height on both machines is adjustable up to an eye level of 18.75 feet (5.70 m) on the MH3049 and 23.5 feet (7.2 m) on the MH3059. On the MH3049, raise time from ground level to maximum height is approximately 14 seconds; lowering time from maximum height to ground level is 12 seconds. Similarly, the raise time from ground level to maximum height on the MH3059 is approximately 17 seconds and lowering time from maximum height to ground level is 13 seconds.
Adjustable sensors control the height of the cab above the ground. A manual safety override in the cab allows the operator to lower the riser in the event of engine power loss.
The MH3049 and MH3059 are equipped with an impact-absorbing falling objects guarding system (FOGS) that protects the operator from flying or falling debris in the work area. An adjustable limiter prevents work tool contact with the cab, and load-holding valves on hydraulic cylinders prevent sudden uncontrolled drop of the boom, stick, cab, or outriggers.
Images from a standard rearview camera are displayed via a high-definition color monitor. A separate monitor displays operating parameters, start-up fluid-level status, machine warnings and activated work functions, which are conveniently controlled with the joysticks. The machine's operating system allows operators to set functions according to preference, and provides maintenance reminders, diagnostic capabilities, and out-of-specification alerts.
Serviceability and work tools
The durable fiberglass gull-wing panel on the engine compartment's right side and the top panel are supported by gas struts, giving ready access to the routine maintenance points in a spacious, lighted compartment. The engine-oil filter and fuel filters are easily accessible through a right side panel at ground level.
An automatic lubrication system services most upper and lower grease points on an adjustable working-time interval, and the grease reservoir requires refilling only at approximate 400-hour intervals. To facilitate machine diagnosis, Cat Equipment Technician™ diagnostic connectors are located in the cab and on the side of the engine.
The MH3049 and MH3059 feature medium-pressure flow from a separate valve for tool rotation and a high-pressure circuit from the main pumps to operate the open/close functions of typical tools, such as orange-peel grapples, clamshells, and log grapples. A separate pump is used to provide hydraulic power to operate a generator for an optional scrap magnet. The generator features a patented Cat solid-state magnet controller that eliminates typical maintenance issues and is supported and warranted through Cat dealers.
