Extending the lower end of Dynapac's mid-weight articulated tandem asphalt rollers are its new 7 t CC224HF, and the split drum version, the 8 t CC234HF. Dynapac, an Atlas Copco subsidiary, emphasises the ergonomic, servicing, and environmental benefits of the new models.
Operator view of the machines' front work areas are through 1 m x 1 m windscreens, and an electronic control panel fully displays all work functions. All levels - water, fuel, voltage and engine hours - are easily viewed, and the operator can change between menus at the touch of a button.
Dynapac placed the machine's engine on the rear module, which reduces noise and engine heat at the operator's platform. A hydraulically driven, temperature-controlled cooling fan also reduces noise, and the exhaust pipe is as low as possible, says the company, to minimise operator exposure to fumes.
The CC224HF and the CC234 HF have ‘soft' starting and stopping to prevent bowing or cracking in asphalt layers, which allows unskilled operators to start and stop without leaving marks, says Dynapac. A safety feature drops the machine out of the ‘soft' mode and brakes it immediately if the control lever is moved quickly, signalling the need for an emergency stop.
Servicing these new machines is easier, too. All filters, for example, are on one side of the machine, and hydraulic lines are routed in segments to allow individual replacement. The machine's drum shock absorbers come off without removing forks or drums.
Two pumps in the vibration system eliminate the need for a vibration switching valve, which, in addition to easing servicing, makes the rollers more efficient and reduces fuel consumption. Both pumps - one for each drum - can be shut off.
A Cummins QSB 3.3 T3 turbo engine, rated at 60 kW, powers the new rollers, and a 74 kW engine is optional. Both engines feature Dynapac's automatic engine idling system to cut idle speed after 10 seconds at full rpm.
Purchase options include an offset rear drum that can be steered independently, air conditioning, an Xenon lighting kit and Dynapac's DCA-A software. This control system feature measures temperatures in front of and behind the roller, as well as the number of passes made on each section of the asphalt.
Snaking through trenches
Perhaps the most technologically innovative and certainly the most interesting looking of recent compaction equipment releases is Rammax's new trench roller, the RX 1510-C. It has the name ‘Viper' because of its ability to shape itself to contours by combining rotation and articulation of the joint between its two modules.
The two ranges of motion enable the 1530 kg Viper to "...move through any kind and shape of material". Another benefit is allowing optimum contact with the work material, thereby maximum compaction, says the company.
A new feature, too, is Rammax's SCT (straight compaction technology) system. Key to its effectiveness is the orientation of the exciter shafts. They are aligned in the direction of the Viper's travel, an industry first, says Rammax, part of Switzerland's Ammann Group.
That orientation allows delivery of equal compaction force to all four drums, which are 850 and 630 mm wide. The aligned shafts also direct compacting centrifugal forces, 7050 kg in the large drum and 3450 in the smaller, independently of machine position.
A Lombardini 15.8 kW LDW 1003 engine powers the RX 1510-CI, and it has a Rammax gearbox with heavy-duty seals and 1:5 ratio transmission. The two components enable the Viper to climb 50% grades when vibrating, and 60% when not.
The Viper, which debuted at Conexpo in Nevada this year, is Rammax's first articulated trench model. It completes Rammax's range of trench rollers, a type it says it invented in 1971. Thomas Remy, sales manager, declines to share prices or specific sales figures, but he does tell IRN that the "...bigger number of machines so far has gone into rental fleets."
Small, powerful compaction
There was no need to change the performance of "the tamping system of our machines," says Ernst Haubach, technical director, and Christian Bartsch, chief engineer at Weber MT. Instead, the German company has improved the operating characteristics and ease of handling of its 4-stroke engine powered vibratory tamper. The result is the 66 kg SRV 620.
The new model has an improved air filtration system with a cyclone pre-cleaner. It ejects coarse dust particles before they reach the main air filter, thus increasing filtration and service life of the Honda engine.
The SRV 620 vibratory tamper has a lower centre of gravity and a re-designed handlebar. Also, Weber says it has considerably reduced hand/arm vibration.
Of possible interest to rental companies eager to reduce operator damage to their assets, this tamper's control system checks engine oil level during start-up. If it is too low, the system aborts start-up and signals the condition by a light-emitting diode. The tamper starts only after an engine oil refill.
From the Belle Group is the 49 kg, two-man lift PCEL 320X plate, which the UK company says is "ideal" for patching compaction. A 2.2 kW Honda petrol engine powers the machine, which generates 11 kN of centrifugal force and 425 kg/m2 of static pressure.
Plate width is 320 mm and contact length is 364 mm, and the PCEL 320X travels at 23 m/min. Its vibrator unit is sealed and oil filled and has "top quality" bearings for reliability and durability, says the UK-based company.
Elsewhere, Doosan Infracore Portable Power has added the BXR-200H to its BXR line of reversible vibratory plate compactors. The new model weighs 235 kg and is powered by a Honda GX240 4-cycle petrol engine.
The BXR-200H generates 31.4 kN of centrifugal force, compacts to a depth up to 460 mm, and compacts at a rate of 486 m2 per hour with its 450 x 740 mm plate.
The latest additions to US-based Stone Construction Equipment's Stomper line of 4-cycle rammers are the XH670D and XH730D. They are both diaphragm carburettor, 2.2 kW Honda engine models introduced in 2007.
The 60 kg XH670 generates an impact force of 1205 kg and has a 25 x 33 cm polyurethane shoe. The 64 kg XH730 has generates an impact force of 1409 kg and has a 28 x 33 cm shoe.
Improved quality from Bomag
Bomag extols the compaction quality of its 7 t BW 154 AP tandem roller, released in the second quarter of 2008. Its control system automatically varies oscillation in both vertical and horizontal directions, depending on compaction dynamics and speed. The machine's Bomag Asphalt Manager system continuously determines and displays the value of dynamic stiffness under the rollers, and its split drum reduces turning and reversing marks.
Making the BW 154 AP easy to use, says Bomag, are a mini steering wheel and an "ergonomically designed" multi-function control lever integrated into the arm rest of the operator seat. An automatic function always turns the seat to the direction of the front drum. Also, the operator can shift the entire operator station sideways and rotate it 270º for optimum visibility.
Pivot steering, five steering modes, and dual-sided crab walk with drum offset up to 1.3 m make the machine very agile and manoeuvrable, says the company.
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Germany's Hamm will soon introduce new tandem asphalt compactors. It is planning the launch of a new line in the first part of October. Marketing manager Gottfried Beer told IRN that "This new line could be very interesting." However, the company is reserving all information about the product until after the world debut at its headquarters in Tirschereuth.
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MBW says it has reduced hand/arm vibration by up to 70% with its Ergo-Tamp pneumatic tamper. The tamper is ideal for the restatement of small excavations associated with utility maintenance. The 20.5 kg tool delivers 1450 beats per minute. US-based MBW introduced the Ergo-Tamp in its domestic market last year, and the product is now available in Europe at a price of €1050. The company also offers a vibration suppression kit, at €420, that can be fitted to any brand of pneumatic tamper.