The Bobcat mini-excavator range has been expanded to provide enhanced performance, product choice and flexibility and now comprises nine models covering operating weights from 1.5 to 5.5 tonnes, says Melroe Ingersoll-Rand, its owning firm.

Three new models have been added to the range: the 331E, which features an extendible dipper stick for enhanced trenching and grading capability; the 322, with an expandable undercarriage offering optimum stability from a combination of the largest track width and the longest tracks on the market and the new top-of-the-range 341 model, with new working group functions producing a digging depth in excess of 4 m, explains a company spokesman.

The nine models have several features which are said to be unique to the Bobcat range. The spokesman elaborates: "The new X-Change Mounting System available on certain models is a quick-change attachment system that provides many advantages over previous attachment methods and other brands of quick-change system.

"It is also the first quick-change attachment system offering commonality between Bobcat mini-excavators and backhoe attachments for Bobcat skid-steer loaders. The mini-excavator range can also utilise an exclusive dipper stick-mounted hydraulic clamp feature, which enhances the ability to pick up blocks of debris or asphalt and load them into waiting trucks and trailers. The hydraulic clamp can be fitted on Bobcat 325, 328, 331, 334, 337 and 341 mini-excavators.

"The 331E mini-excavator features an extendible dipper stick, making it ideal for applications that occasionally require increased reach and dump height performance, particularly in trenching and grading applications. The dipper stick on the 331E mini-excavator can be extended by 830 mm, providing 5,610 mm of reach at ground level and a dump height of 3,432 mm to clear high-walled trucks.

"The foot pedal used to operate the auxiliary hydraulics on the Bobcat 331E mini-excavator also controls the extension and retraction function of the dipper stick, which can be activated simultaneously with other work group functions. Hydraulic oil from the mini-excavator's auxiliary hydraulic circuit is routed to a cylinder inside the dipper. The extendible dipper ensures long life performance through the use of a 'Hardox' wear material on both the inner arm and outer stationary arm of the dipper section of the 331E mini-excavator.

"Mini-excavators with a reach as long as that offered by the 331E model with dipper stick extended do not need to be positioned as often when trenching and grading soils. This decreases the average working cycle time and increases the machine's overall productivity.

"The expandable undercarriage on the 322 mini-excavator achieves the same results - it can be hydraulically retracted or expanded allowing access to confined spaces and increased functionality in digging applications. When the undercarriage is retracted, the 322 measures just 980 mm wide, so the machine can gain entry to sites through narrow gateways, doorways and trenches.

"Once the 322 is in place on the excavation site, the undercarriage can be expanded to 1,360 mm, the widest on the market. Coupled with the longest tracks available, the expanded width between the tracks provides the best stability in the 1.5-tonne class and better side digging and lifting performance than traditional mini-excavators. This feature also allows the mini-excavator to straddle narrow trenches in cable-laying applications.

"The expandable undercarriage is simple to use - the operator just lifts the machine off the ground using the blade and boom functions and then the track is extended or retracted using the blade lever. A rocker switch located to the right of the operator diverts flow between the blade function and the undercarriage.

"The 322 also offers enhanced operator comfort. A new track and roller system, similar to that used on the larger Bobcat mini-excavator models is now used, providing a smoother ride for the operator. This results from the fact that the rib of the roller no longer rides on the bottom of the metal imbeds; instead, the rollers now ride on top of the metal imbed guides. The same design is now available as standard on the 320 mini-excavator."

With a dipper stick length of 1,925 mm, the new 341 mini-excavator has a maximum digging depth of 4,060 mm, a maximum dump height of 4,045 mm and ground level reach of 6,155 mm. The 4-m-plus digging depth is an obvious advantage, providing increased productivity in excavating work, he says. The increased vertical wall digging depth is ideal for applications such as foundation work and the increased dump height is excellent for applications such as truck loading, according to the spokesman.

The 341 model is aimed at the 4.5 to 5.5-tonne segment of the market as is the enhanced 337 mini-excavator.

"The 341 and 337 mini-excavators have an enhanced work group geometry based on a new dipper stick design and a new bucket cylinder with a longer stroke. The larger angle of bucket rotation that results ensures optimal dumping capacity and, coupled with the greater reach, provides a significantly increased vertical wall digging depth. The new X-Change Mounting System is now available on the Bobcat 331 and 334 models. Among the advantages it offers over other brands of quick-change system is increased safety - the X-Change design prevents buckets from falling off when the retaining bolts are released. The operator must lower the excavator arm to the ground to release the bucket.

"Exclusive to the Bobcat mini-excavator range, the hydraulic clamp option comprises a grapple for clamping, a hydraulic cylinder (actuated by the auxiliary hydraulic system on the mini-excavator) and the hoses needed for hook-up. The hydraulic cylinder that operates the clamp is mounted in an existing bracket on the dipper stick of the mini-excavators. It can be used with both the X-Change system or traditional pin-on buckets.

"The 331E, 322 and 341 complement the existing models in the Bobcat range - the 320, 325, 328, 331, 334 and 337 mini-excavators. Bucket breakout forces of all nine machines in the range are amongst the highest in their respective operating weight classes, ranging from 1516 daN for the 320 model to 4481 daN for the largest 341 model.

"All Bobcat compact equipment and attachments are backed by a worldwide network of more than 900 dealers, including over 160 distributors serving Europe, the Middle East and Africa, with factory-trained service mechanics and quality spare parts," the spokesman concludes.