Komatsu redefines compact design with its tight tail excavator

Nov 01, 2023

Komatsu has introduced a new "tight tail swing" excavator well-suited for urban environments, confined spaces and crowded jobsites.

With its 68-horsepower engine, six work modes and swing radius under 5 feet, the PC78US-11 can handle precise digging, as well as large excavation tasks.

The 12-foot 2-inch boom has a greater raising angle and a short implement swing radius (6 feet 9 inches minimum), giving the PC78US-11 the ability to dig efficiently in a crowded space. At the rear, the tail swing radius measures just 4 feet 7 inches. Viewed from above, both the front and the rear corners of the superstructure are rounded, with the maximum cab extension over the tracks at just 9 inches.

Good operators like a quick machine, and Komastu's faster boom up and swing speed increases productivity by 9%. To better match machine performance to the application, Komatsu arms the PC78US-11 with six work modes: power, economy, lifting, breaker, attachment-power, and attachment-economy.

For operators who prefer backhoe-style controls, a pattern change selector valve comes standard. The grading blade has a new moldboard profile to improve backfilling and grading efficiency. The PC78US-11 accepts buckets from 0.10 to 0.26 cubic yards.

A new high-output 2.4-liter, Tier 4 Final engine gives you ground-level access to service points. The heavy-duty, high-pressure common rail fuel injection system and cooled exhaust gas recirculation (CEGR) achieve near complete combustion in cylinder to reduce emissions.

A Komatsu diesel oxidation catalyst removes exhaust soot and enables 100% passive regeneration without a diesel particulate filter or regular refills of diesel exhaust fluid. The no-DPF, no-DEF design translates into lower owning and operating costs, reduced maintenance and one less component to replace or worry about.

Komatsu's compact engine makes room for a fan clutch system, allowing engine and hydraulic system tuning to reduce noise by a full decibel. Typical in-cab noise levels measure 71 decibels — about the same as a household vacuum cleaner. When engine cooling is not required, the viscous fan clutch reduces parasitic horsepower draw. Overall engine improvements boost fuel efficiency as much as 13%.

The air-suspension seat has deep side supports and an adjustable backrest angle to support operators of all sizes. The cab comes with AM/FM radio with USB and Bluetooth technology.

Komatsu improved cab dampening by incorporating a spring and a longer stroke on the viscous cab mounts. This, plus a beefed up deck, reduces vibration to the operator to keep him or her more comfortable and focused throughout the day. The sealed and pressurized cab keeps dust out and automatically maintains temperatures to the level set on the monitor.

A sliding cab door makes access easier, especially when you’re entering or exiting the excavator up against a wall or in confined spaces. The cab is ROPS certified and satisfies the requirements of ISO OPG Top Guard Level 1 for falling objects.

Crowded jobsites often restrict sight lines, so Komatsu added a 7-inch LCD display to the PC78US-11 with a standard rearview camera image. LED lights provide nighttime illumination of the jobsite.

The variable displacement/axial piston hydraulics for the boom, arm, bucket, swing and travel circuits offer a maximum flow of 44.4 gallons per minute. Relief-valve settings for implement circuits are rated at 4,264 psi. The auxiliary circuits put out 36.5 gpm/3,830 psi (two way) and 21.1 gpm/2,490 psi (one way).

For travel and trailer considerations, the PC78US-11 has an operating weight of 17,747 pounds.