Caterpillar unveils new compact excavator and loader
By Chris Sleight24 January 2011
The latest excavator is the 305.5 D, a 5.5 tonne machine that is part of a new initiative from the company to have equipment nomenclature that reflects machines' operating weight. The maximum counterweight overhang of the compact radius machine is just 4 in (102 mm) over the outside of the undercarriage footprint.
Another feature of the counterweight is that it is now fully integrated into the machine, as opposed to the bolt-on counterweight of the C-series excavators. With this has come greater stability - according to marketing engineer, Rob Jackson, "We now have more stability on every model." He added that this was something C-series machine users wanted when using long boom and stick configurations with heavy attachments.
At the front of the machine, there the bucket curl has been increased to 200°, making it easier to dig trenches with a flat bottom, and to retain more material in the bucket when loading trucks.
The machines ship with either a mechanical or fully hydraulic pin grabber quick hitch, each of which has two locking devices. In the case of the mechanical hitch, the back pin is locked automatically as a new attachment is picked up, while the front is engaged manually with a spanner. However, the rear lock can only be disengaged with a spanner, making it impossible for attachments to be dropped.
In the case of the hydraulic coupler, the manual spanner work is replaced by controls in the cab. This means the operator does not have to get in and out of the machine to secure attachments.
With the US market in mind, the stick also features a bracket for adding a thumb attachment, which can be run from the auxiliary hydraulic circuit.
Inside the cab, the only two pedals are for travel, with the rest of the controls in the joysticks, keeping the floor area as free as possible. There is also a switch to the left of the operator's seat to switch between an excavator and backhoe control pattern. The seat slides, tilts and is fully suspended.
All the D-series machines come with an auto idle control, which drops the engine revs to idle if the controls are not touched for three seconds, cutting down on noise and unnecessary fuel consumption.
The latest addition to Caterpillar's compact tracked loader range meanwhile is the 259B3 from the B Series-3 range. It is one of the smaller machines in this range, with a width of 66 in (1.68 m), when mounted on narrow tracks. Power comes from a 71 hp (53 kW) engine, and the rated capacity is 1338 kg. The loader features a vertical loading path, which is to say the maximum reach horizontal reach comes at the top of the bucket cycle, making it suitable for duties like truck loading.
Two-speed travel is standard, giving the 259B3 a maximum speed of 8.5 miles/hour (13.7 km/h), and the suspended undercarriage makes for a smoother ride for the operator.