Two new Cat Next Gen mini excavators built for stability
By Jenny LescohierNovember 09, 2021
Caterpillar’s two new mini excavator models complete the Next Gen family of compact diggers with a focus on increased stability.
The new 4-tonne Cat 304 and 5-tonne Cat 305 CR Next Generation mini hydraulic excavators have higher bucket breakout forces and deeper standard digging depths for performance that’s improved up to 20% over their E2 series counterparts.
Extended grease intervals and filter service life, combined with common components throughout the line and flat, easy-to-replace side panels, are said to deliver up to 10% lower owner and operating costs, according to Caterpillar.
Cat’s Next Gen mini excavator family is now complete
Greg Worley, market development for Caterpillar, explained the new 304 and 305 CR models are the final machines to be reengineered to the Cat Next Generation mini hydraulic excavator line concept. From the 1.5- to 10-tonne class models, all 17 – 20 Cat mini hydraulic excavators in the range (depending on region) offer common features and consistent controls layout to simplify training and operator adaptation.
Built with a new reduced radius design, the 304 features a narrow, 66.9-in track width which is 10 in slimmer than the 304 E2, for more versatility and access to confined spaces. While narrower, the new 304 design increases performance, balance and stability of the 4-tonne class model. Its reduced radius allows for greater stability, both 360-degree and when traveling with loads, while its extra counterweight option takes the model to an even higher level of stability.
“The overhang is 14 in without the counterweight, 18 in with the counterweight. That kind of weight takes you to a whole new league,” Worley said. “This machine is more stable than its predecessor. We’re actually going to put this weight on standard through our distribution centers. This is the way we intend to bring this to the North American market, ready to work when it’s very demanding.”
The new engine on the 5-tonne class Cat 305 CR excavator delivers nearly 9% greater power to increase machine performance. Hydraulic system improvements provide higher breakout forces – 11,061-lbf bucket, 6,362-lbf standard stick and 5,665-lbf long stick – to improve digging efficiency in hard rock applications.
The 305 CR also offers 5.6-in deeper dig depths than the 305 E2, giving it more application flexibility. Its compact radius swing reduces overhang when working to the side, while its 78-in track width and new extra counterweight option help to optimize stability and lift performance in confined spaces.
“On the 5-tonne machine we go from a reduced radius to a compact radius. We have about 4 to 5 in of overhang without the counterweight,” Worley said. “The track is a little bit different. The 4-tonne machine only has a steel track or rubber belt (the rubber belt is 90% of the application in North America). On the 5-tonne machine, you can get steel track, rubber belt or steel track with rubber pad, which is where you get the best of both worlds. When you have this type of combination, you’re also adding more weight low down, so you increase the stability without the extra counterweight.”
Smart electronic pump adjusts performance on the fly
Key to the new excavators’ enhanced performance is an electronic pump which senses everything from ambient temperature and altitude to hydraulic load.
“Whatever the operator commands from the machine, whether it’s traveling up a hill with a load of dirt or when the engine starts to lag due to altitude, the electronic pump knows the operator is asking the machine to do something harder and produces more torque,” explained Worley. “That’s why these machines are the most efficient and the most powerful on the market. The electronic pump is standard on every Next Gen machine.”
Dozer blade option
Both excavator models now offer an angle dozer blade option to optimize machine flexibility in backfilling and finish grading applications. In addition to offering ample above- and below-grade travel with standard float function for easy clean-up, the angle blade moves 45 degrees left or right of center. Increasing efficiencies and reducing operator interaction with final grading, angle blade movement is controlled by the right-hand joystick, while the left joystick handles machine drive.
Tailoring machine weight to job requirements, interchangeable counterweight packages offer the balance between low ground pressure and lifting performance. Their industry-exclusive Cat Stick Steer System simplifies machine control by allowing the operator to switch from conventional lever/foot-pedal steering controls to low-effort joystick operation. Two travel speed ranges and standard cruise control facilitate moving around the jobsite with minimum operator interaction.
Meeting U.S. EPA Tier 4 Final and EU Stage V emission standards, the turbocharged Cat C1.7 Turbo engine delivers higher power than the previous C2.4 engine. Standard auto idle, auto engine shutdown and efficient load-sensing hydraulics with variable displacement pump help to lower fuel usage at the site for more affordable operation.
High main-relief pressures, coupled with flow rates, generates the hydraulic capacity for high digging and lifting forces and more efficient use of a range of attachments. Complete with quick-disconnect lines, the standard auxiliary system provides the choice of one-way, two-way or continuous flow.
Next Gen comfort, visibility
Common to most Cat next generation mini hydraulic excavators, the sealed and pressurized cab enclosure is available with heating and/or air conditioning for all-weather climate control. The cab’s large glass areas plus skylight afford all-around visibility. The large display with advanced touchscreen option provides intuitive machine function control and easy monitoring of critical operating parameters. A canopy option is available in some regions.
Daily maintenance checks for the 304 and 305 CR are quickly made from ground level through side doors. Expanded use of common parts throughout the line plus their damage-resistant exterior construction help to reduce parts inventory investment and lower repair costs. Increased service intervals mean these excavators spend more time on the job and less time in the shop.
Cat’s line of mini excavators range from the 2,061-lb 300.9D on the low end to the 22,451-lb 310.