TM 5-3805-294-10
OPERATOR MAINTENANCE
EQUIPMENT DESCRIPTION AND DATA
EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES
Overview
The Hydraulic Excavator Type 1 (HYEX), NSN 3805-01-573-0677, is a 21-24 Metric Ton, diesel powered, crawler
mounted, hoe type hydraulic excavator. The HYEX digs, elevates, swings, and dumps material by action of the boom,
the arm, and the bucket.
The HYEX is powered by a John Deere six-cylinder, PowerTech, 414 cu in. (6.8 L) engine driving two identical
variable displacement, bent-axis, piston type hydraulic pumps and a fixed displacement, external gear pilot pump.
The hydraulic pumps and pilot pump combination provide the hydraulic and control pressure for the machine to
operate.
Propulsion is provided by two-speed hydraulic travel motors, (one on each side), that drive two track chains with 51
triple semi-grouser 32 in. (800 mm) wide track shoes. Each hydraulic travel motor is of a bidirectional planetary drive/
axial piston motor design with spring applied and hydraulically released travel brakes.
The HYEX upper structure is capable of continuous 360degree rotation driven by a swing gearbox and bidirectional
swing motor mounted on top of the swing gearbox. The swing motor has a spring applied and hydraulically released
park brake. The park brake prevents the upperstructure from uncontrolled swinging. The swing park brake is released
when swing, boom, arm, or bucket function is actuated.
The boom, arm, hydraulic thumb, and bucket hydraulic cylinders provide linear actuation for their associated
components. These cylinders vary in size, but are similar in design and function.
The HYEX is configured with a retractable hydraulic hose reel, with pressure and return hoses of 50 ft (15.24 m)
length and 0.5 in. (1.27 cm) diameter, located on the cab side of the excavator to operate hand-held tools. The
hydraulic circuit is a controlled pressure source with adjustable flow rates between 8-12 GPM (30.28-45.42 LPM)
with adjustable nominal pressure limit of 2,000 psi (137.89 bar).
Operating Capabilities
The HYEX can excavate undisturbed hard, medium, and soft soils to a minimum depth range of 22-24 ft
(6.7-7.3 m). It has a minimum horizontal bucket reach at ground level of 30 ft (9.14 m). Maximum possible bucket
and stick forces are capable of penetrating and excavating very difficult soils (such as caliche) and conditions (such
as frozen soils).
The HYEX is capable of dumping into the Family of Medium Tactical Vehicles (FMTV), 5 ton with a bed height of 6
ft 9 in., to a M917 20 ton with a bed height of 10 ft 2 in. HYEX is capable of dumping into an Engineer Mission Module
(EMM) when on equal level ground.
The HYEX operates under environmental climatic conditions from -25F to 120F (-31.6C to 48.8C) without
restriction, and when required, down to -40F (-40C) using the coolant heater cold weather starting kit.
The HYEX will start and operate during and after fording operations in fresh water in any depth up to 40 in. (1 m)
including wave action.
Attachments for HYEX are connected to the excavator arm (stick) using the Quick Latch (a hydraulic quick connect/
disconnect coupler system) and hydraulic quick-disconnect hydraulic hose connections on the arm. The only
exception is the Deep Digging Attachment Arm that must be pinned directly to the end of the excavator arm.
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