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Origin and Purpose of the ZX870-3
The Hitachi ZX870 series—part of the ZAXIS family from Hitachi Construction Machinery—was designed to serve heavy-duty excavation, dredging, demolition and offshore tasks. The “870” designates an 80-ton class machine (approximately) and the “-3” indicates the third generation of the model. The operating weight of the ZX870 LCH-3, for instance, is roughly 84 tonnes (≈ 185,000 lb).
The machine is offered with different boom/arm combinations—such as a conventional BE-boom/BE-arm or an extended H-boom/H-arm—to suit tasks from standard excavation to long-reach, dredging or demolition.
Triple-Boom Concept and Its Advantages
One distinctive version of the ZX870-3 involves a “triple-boom” or adjustable-boom configuration, typically used in heavy duty tasks like laying large concrete blocks, offshore trenching, or demolition. The concept of a triple boom (one extra section) allows the machine to reach farther or work from pontoons while still maintaining strong breakout force. As one operator explained, the advantage lies in “break-out force because the adjustable boom and the very special and very strong construction.”
Advantages of this configuration include:
Some benchmark figures for the model (LCH-3 variant) highlight its capability:
The triple-boom ZX870-3 has been deployed in demanding environments. One documented case involved a machine operating on a pontoon for trenching work at sea; the flexible boom enabled placement of heavy concrete blocks and trenching beyond standard reach.
Another scenario is demolition: with a heavy-duty boom configuration and large hydraulic hammer attached, the machine replaced multiple smaller units, gaining productivity by virtue of reach and force. The extra boom segment also allowed work from a safer distance when dealing with unstable structures.
Operational Considerations & Maintenance Implications
Using a triple-boom excavator involves some trade-offs:
The Hitachi ZX870-3 configured with a triple-boom attachment represents a powerful and flexible machine capable of tackling major excavation, dredging or demolition tasks. It combines the core ZAXIS series robustness with extended reach and heavy-duty capability. Success in use depends on matching job demands to machine spec, rigorous maintenance of structural and hydraulic systems, and managing the logistic realities of larger boom configurations. For contractors working in demanding terrain or requiring reach combined with strength, the triple-boom ZX870-3 remains a top-tier choice.
The Hitachi ZX870 series—part of the ZAXIS family from Hitachi Construction Machinery—was designed to serve heavy-duty excavation, dredging, demolition and offshore tasks. The “870” designates an 80-ton class machine (approximately) and the “-3” indicates the third generation of the model. The operating weight of the ZX870 LCH-3, for instance, is roughly 84 tonnes (≈ 185,000 lb).
The machine is offered with different boom/arm combinations—such as a conventional BE-boom/BE-arm or an extended H-boom/H-arm—to suit tasks from standard excavation to long-reach, dredging or demolition.
Triple-Boom Concept and Its Advantages
One distinctive version of the ZX870-3 involves a “triple-boom” or adjustable-boom configuration, typically used in heavy duty tasks like laying large concrete blocks, offshore trenching, or demolition. The concept of a triple boom (one extra section) allows the machine to reach farther or work from pontoons while still maintaining strong breakout force. As one operator explained, the advantage lies in “break-out force because the adjustable boom and the very special and very strong construction.”
Advantages of this configuration include:
- Greater reach and flexibility: The additional boom section allows the excavator to work over longer distances or from higher surfaces.
- Capacity to handle heavy attachments: With the triple-boom structure built for strength, the machine can manage large tools (e.g., hydraulic hammers, heavy grabs) that demand high structural integrity.
- Versatility across job types: While the standard excavator is set for digging, the triple-boom version shifts toward demolition, dredging, or specialized tasks.
Some benchmark figures for the model (LCH-3 variant) highlight its capability:
- Net power: ≈ 532 hp (≈ 397 kW) at 1,800 rpm.
- Operating weight: approx. 185,188 lb (≈ 84,000 kg) in one spec.
- Maximum digging depth (with certain boom/arm): up to 29 ft (≈ 8.9 m) assuming the longest arm and boom.
- Max reach along ground: up to 45 ft (≈ 13.7 m) in extended-reach versions.
- Hydraulic pump flow capacity: around 279 gpm (≈ 1,056 lpm) and relief valve pressure approx. 4,975 psi (≈ 34,300 kPa).
The triple-boom ZX870-3 has been deployed in demanding environments. One documented case involved a machine operating on a pontoon for trenching work at sea; the flexible boom enabled placement of heavy concrete blocks and trenching beyond standard reach.
Another scenario is demolition: with a heavy-duty boom configuration and large hydraulic hammer attached, the machine replaced multiple smaller units, gaining productivity by virtue of reach and force. The extra boom segment also allowed work from a safer distance when dealing with unstable structures.
Operational Considerations & Maintenance Implications
Using a triple-boom excavator involves some trade-offs:
- Increased structural load: The added boom section and attachments place greater demand on pins, bushings, hydraulic cylinders, boom foot etc.—maintenance must be more frequent.
- Transport logistics: Longer boom/arm setups extend transport length—one spec being 14.77 m transport length for the LCH-3 model.
- Counterweight and balance: To maintain stability when working at long reach with heavy attachments, counterweight must be adequate and swing radius considered.
- Hydraulic system sizing: Higher demands on hydraulic flow and pressure require checking pump capacity, hoses, and cylinder health regularly.
- Boom section attachment/interchange: Some machines allow swapping boom sections (e.g., full -wing reach vs standard) which involves precise pin torqueing, alignment, and inspection for fatigue cracks.
- Break-out force: The maximum force the bucket face can apply to break material free (measured in kN or kgf).
- Boom/Arm combination: Refers to the length and type of boom and arm attached; “H-boom” indicates longer reach heavy duty version.
- SAE/PCSA heaped bucket: Standard bucket capacity measured by SAE (American) or PCSA (European) methods.
- Ground pressure: The pressure the machine exerts on underlying surface expressed in psi or kPa—maintenance of reasonable values aids mobility.
- Operating weight: The weight of the machine ready for work including counterweights, operator, full fuel and fluids.
- Conduct routine structural inspections of boom foot mounting, welds, pin holes, especially when using heavy attachments or extended-reach configurations.
- Monitor hydraulic pump flow and cylinder pressures; trend early increases in draw or drops in performance.
- Maintain transport tracking; ensure boom sections are properly secured and tagged.
- Choose attachments matched to the machine’s rated breakout and arm crowd forces; avoid oversizing equipment beyond structural capability.
- Documentation of job-cycle hours, attachment hours, and maintenance intervals helps plan part replacement proactively.
The Hitachi ZX870-3 configured with a triple-boom attachment represents a powerful and flexible machine capable of tackling major excavation, dredging or demolition tasks. It combines the core ZAXIS series robustness with extended reach and heavy-duty capability. Success in use depends on matching job demands to machine spec, rigorous maintenance of structural and hydraulic systems, and managing the logistic realities of larger boom configurations. For contractors working in demanding terrain or requiring reach combined with strength, the triple-boom ZX870-3 remains a top-tier choice.
