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Ammann Compaction Celebrates 100 Years
Traditional “static” compaction is based on the heavy weight of the roller. The machines become increasingly heavier, rolling majestically along surrounded by impressive clouds of steam due to a lack of diesel engines. Back then, they were known as compaction trains: they consisted of the roller, the coal tender, the water wagon and the caravan for the operator. He never went home on the weekend but rather stayed with his train throughout the entire road-building season. To this day, the concept of the static three-wheeled roller is held in high esteem by road-builders around the world. Equipped with pneumatic tires as an alternative, these static models have a balanced weight distribution that achieves an unsurpassed compacted surface smoothness. Just three years later, in 1914, the patented Ammann Rugel roller, a manually-controlled roller weighing 1.6 t and driven by a combustion engine, is launched on the market. The advantage: it enables the professional compaction of smaller roadworks, pavements and industrial areas. Tar-based Macadam surfaces are replaced by bitumen mixtures from 1918 on. Ammann’s engineers use this ground-breaking development to gain experience that will flow into the design of the next generation of asphalt mixing plants. The developers of compaction rollers also produce a number of new models characterised by a number of technical advantages: The compact range is controlled by an operator sitting on top of the roller; its responsive steering – even though mechanical in nature – leaves hardly any offset tracks, whilst its drive is virtually jolt-free and guarantees a presentable, smooth surface. At the end of the 1920s, the occurrence of two dam bursts with grave consequences in America triggered a development in compaction technology that marked an epochal turning point. California’s water authorities defined the measurement method developed by American engineer Ralph Proctor as the minimum target requirement for adequate substrate compaction. This degree of compaction, the Proctor Value, cannot be achieved with the conventional method of static compaction. (Ralph Proctor’s discovery demonstrated in particular that the moisture content of a substrate is of crucial importance to the maximum possible degree of compaction.)
Once again, Ammann’s development engineers see an opportunity welcomed by site engineers to achieve more efficient compaction results on earth and asphalt substrates with the compact machines of a 2-t weight category. The successful DTV (Double Tandem Vibration) range is developed at the end of the 1960s, first in the form of a vibrating drum followed just a few years later by double vibration; it offers the operator a broad spectrum of possible uses: Offset drums prevent the creation of tracks during asphalt compaction, whilst an articulated joint capable of oscillating by up to 8° – the object of an Ammann patent – follows twists in the surface without causing cracks. And the side clearance enables compaction right up against the wall. These “self-driving” machines enable the operator to concentrate fully on the job in hand without tiring. Walk-behind vibratory rollers were developed in Hennef during the mid-1960s and found a market niche in the 500 to 800 kg range; the rapid development of urban road networks and a variety of uses soon made any building site virtually unthinkable without them. Nonetheless, there was still room for further development in the category of light-weight mini-compactors. Unidirectional and reversible vibratory plates equipped with powerful petrol or diesel engines met a demand that is still growing today. A trading partnership for walk-behind rollers founded in the 1970s culminated in the acquisition of the German company and, as a result, an expedient addition to the model range that secured a number of valuable patents for Ammann.
And Ammann is once again a step ahead of the demands raised by road-building engineers. The self-regulating measuring and control system for compaction rollers patented as Ammann ACE and introduced during the mid-1990s transforms the machines into intelligent, thinking partners. This ingenious technology then becomes available for Ammann machines of every type and class in the years that follow. Today, even hydrostatic vibratory plates from Ammann are able to increase or decrease their compaction force depending on the level of compaction and to inform the operator continuously of the compaction result. Ammann – a valuable partnership In response to the demand for greater production capacity, the company’s shareholders decided to make appropriate investments to implement the growth phases and secure its outstanding know-how: The specialist for walk-behind double vibratory rollers and vibratory plates in Hennef, the globally established market leader for vibratory trench rollers Rammax in Metzingen (both in Germany), and finally, in 2005, the specialist for single drum rollers in Nove Mesto, Czech Republic, were the acquisitions that, in addition to rapid organic growth, have made Ammann one of the world’s leading manufacturers of a complete range of compaction machines. Ammann’s compaction machines are celebrating their 100th anniversary this year. The revolutionary development is a continuous challenge to Ammann’s engineers to search for more economical drive solutions and more effective vibration technology. Respect for the environment is the driving force behind Ammann’s research into conservative and safe alternatives. Every employee contributes towards tackling these demanding challenges. |
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The new era: Vibratory rollers
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