Importance

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Abstract

The invention relates to a travelling finisher apparatus for laying down a road surfacing layer of a bituminous compound material, comprising a first precompacting and levelling screed carried by a frame, and optionally a second levelling screed connected to a vibratory drive arrangement, whereby a particularly high degree of compaction is achieved so that subsequent roller compaction is not required. This is accomplished by providing a vertically guided compactor bar extending transversely of the direction of travel at the rear of the first screed and being of substantially narrower width than said first levelling plank, said compactor bar being continually in contact with the surface of the precompacted surfacing layer and adapted to be acted on by linear pulsating forces acting between the frame and the compactor bar, and generated by a drive source the reaction forces of which are absorbed by the frame. As the reaction forces are taken up by the frame, it is possible to make use of the mass inertia of the frame and the components associated therewith for generating extraordinarily high force levels at the compactor bar. Together with the narrow contact surface of the compactor bar, this results in very high area unit loads enabling the required high compaction degrees to be achieved. This is also enhanced by tuning the frequency of the compaction force pulses to the natural frequency of the system. The compactor bar and the levelling screed following it may be divided into sections adapted to be angularly adjusted relative to one another for forming roof- or trough-shaped surface profiles.

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First Claim