Caterpillar offers the Cat 307.5 and Cat 310, its Next Generation mini hydraulic excavators in the 7- to 10-t category. The 307.5 weighs from 7,532 to 8,233 kg depending upon configuration. It is a standard tail swing model with a fixed boom, powered by a Cat C2.4 turbo diesel engine rated at 41.7 net kW. Caterpillar said the machine can be ordered with a standard stick delivering a 4,107-mm dig depth, or a long stick that increases the depth by approximately 560 mm.
The 310 model weighs between 9,601 and 10,182 kg, equipped with a fixed boom, standard tail swing, and twin blade cylinders for handling heavy-duty dozing chores. This machine uses the Cat C3.3 diesel engine rated at 52.4 net kW and has a dig depth of 5,174 mm.
Both the 307.5 and 310 are fitted with cabs, sealed and pressurised to ensure a clean environment, and feature a redesigned heating/ventilating/air conditioning system that ensures all-weather climate control. The suspension seats offer a retractable wide seatbelt, and the operating consoles have adjustable wrist rests. In-cab sound levels are 72 dB(A).
Intuitive controls include the Next Generation LCD monitor that provide easy-to-read machine information and features a jog-dial for easy navigation, including setting personal operating preferences. For greater convenience, a control-pattern changer allows operators to quickly adapt the machine to their preferred joystick movement. A machine security system is available as key with pass code or push-to-start with fob. The machine can also be Bluetooth enabled through the radio.
The large front window slides upward and stores conveniently overhead, and expansive glass areas on the sides and rear of the cab, plus a skylight, provide all-around visibility. A rear-view camera can be integrated into the monitor.
An exclusive feature for new Next Generation models is the Cat stick steer system, which enables the operator to switch (with the touch of a button) from conventional lever/foot-pedal steering controls to low-effort joystick control. Automatic two-speed travel is standard, as is a cruise control system that further simplifies machine travel.
The cab's protective structures - ROPS (ISO 12117-2:2008), TOPS (ISO 12117:1997) and top guard (ISO 10262:1998 Level II) - are designed to promote a safe working environment for the operator, and controls are protected via a hydraulic lock-out. Halogen boom lights help illuminate the work area, and optional LED lights, front and rear, help to further enhance visibility. The easy-to-transport Next Generation models also feature tie-down points on the track frames to facilitate securing the machine.
These new mini excavators use an efficient, fuel-saving, load-sensing hydraulic system with an electronically controlled variable-displacement piston pump capable of oil flows up to 167 l/min (the 307.5) and 233 l/min (the 310). Generous flow rates, coupled with high main-relief pressures, provide the machines with the hydraulic capacity to generate increased travel performance, and higher digging and lifting forces, as well as to handle powered attachments.
For improved versatility, the auxiliary hydraulic system (complete with quick-disconnect lines) delivers one-way, two-way and continuous flow. Manual and hydraulic couplers are available, and the new models are available with a thumb-ready package and a certified lifting eye. Front-shovel operation, a capability that lends an extra measure of precision when digging around utilities, can be accomplished with both pin-on and coupler-mounted buckets.
The Cat 307.5 comes equipped with an undercarriage length of 2,880 mm, while the Cat 310 has a longer undercarriage (3,301 mm), designed for higher stability. A dozer blade further expands the capability of the new models, allowing the machine to handle backfilling and grading tasks. The blade features ample travel, above and below ground, and has a float function. Major structures for the Next Generation mini machines - upper and lower frames, track frames, boom, and stick - are patterned after their larger Cat excavator counterparts and designed for long-term durability.
Routine maintenance check points are accessible at ground level through the side doors, and the battery is maintenance-free. Side panels are flat and recessed to protect them from damage and have been designed for easy replacement.