by Kyle Molyneux | Tue 13 Jul 2021
Kobelco SK50SRX-7 and SK58SRX-7 minis
The next generation Kobelco SK50SRX-7 (4.66-tonne) and SK58SRX-7 (5.1-tonne) mini-excavators are said to deliver increased performance and productivity and follow Kobelco’s Performance X Design concept for enhanced design and operator comfort.
The all-new, 29.1kW SK50/58SRX-7 machines benefit from improved hydraulic performance when compared to the previous models (SK45SRX-6E and SK55SRX-6E). The new hydraulic system shortens the digging cycle time by up to 11% (SK58SRX-7), and this performance can be maintained without reducing speed, even with a heavy load or when travelling up a slope. In addition, the replacement of the travel motor and swivel joint has increased the travel and hill climbing speeds by up to 12% and 10% respectively (SK58SRX-7).
Other benefits of the new hydraulic system include smoother operation and improved levelling performance. The Integrated Flow Pump System enables operators to harness extra output from the third pump, which otherwise powers the swing and dozer circuit. This additional output is directed to the arm and boom for added power when digging, resulting in a fast and smooth raising operation, even with heavy loads.
Like all Kobelco’s Short Radius (SR) machines, the SK50/58SRX-7 feature a compact tail swing for operation in restricted spaces, such as on urban or residential jobsites, for a smaller working footprint. However, a larger boom and arm are provided as standard equipment for a wide working range.
The machines’ unique blade design ensures the earth always falls forward and not behind the blade when dozing, meaning that only ‘one pass’ is needed and saving time on the jobsite. Inside the cabin, the dozer can be controlled by the ergonomically designed lever, which is easier to grip, and the first and second speed switches have been repositioned in order to improve manoeuvrability. An angled dozer and floating dozer are also available as optional equipment.
In terms of durability and reliability of the SK50/58SRX-7, the boom, arm and swing bracket all have large cross-section segments for added attachment strength, and the bolt-tightened pins firmly lock the boom to prevent the boom top from opening laterally. The bucket features a cast-iron idler link, and the box construction dozer supports provide greater strength.
Despite its compact size, the SK50/58SRX-7 also follows the same Performance X Design concept for improved design and operator comfort, as seen on the recently released Kobelco SK210(N)LC-11 and SK500/530LC-11 machines. A Grammer suspension and reclining seat takes care of shock absorption and comfort, while improved ergonomics enable the operator to move the control levers horizontally without twisting their wrist, and the enlarged wrist rests keep the operator’s forearms in position, reducing fatigue and allowing stable operation. The air conditioner, smartphone holder (Bluetooth handsfree-enabled), USB/AUX port, DAB+ Radio, cup holder and coat hook provide additional comfort.
A colour display comes as standard and provides access to operating history, maintenance cycle and fuel and water temperature gauges. It can also be used to adjust the hydraulic oil flow to the attachments. When in Energy Conservation mode, the SK50/58SRX-7 adapts S-mode to enable 26% less fuel consumption when compared with H-mode (SK58SRX), and an auto-deceleration switch is installed as standard. The shape of the access shutdown lever has been adapted and the door also opens widely for improved access. The window on the right side of the cab can be opened and closed both forwards and backwards to facilitate ventilation and make it easier to hear outside noise.
In terms of operator safety, the high-strength cab/canopy meets ROPS, TOPS and OPG Level 1 (Top guard) standard, while an LED work light, which comes as standard, is mounted under the boom to protect from damage. The wiper mount has been moved to the upper right of the cab support and the skylight opening has also been enlarged, improving operator visibility of the jobsite. When it comes to cabin noise, Kobelco’s innovative Integrated Noise & Dust reduction cooling system (iNDr), usually seen in Kobelco’s heavier machines, achieves low noise as well as exceptional engine cooling, enhanced reliability, minimal machine downtime and a more comfortable working environment, reckons Kobelco.
The further improved iNDr+E system on the SK50/58SRX-7 functions in the same way as the iNDr system on the SR machines, but features air intake at the front of the machine and directs the muffler exhaust underneath. The exhaust is further slowed down and cooled through the offset duct and then discharged into the atmosphere. The SK50/58SRX-7 also offers access to the engine compartment for daily maintenance that reduces time for inspection and cleaning. The iNDr filter has a high-density mesh of 30 lines per inch to collect dust.
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