Wirtgen Gmbh

Markus Schäfer

Christian Berning

Dieter Simons

Stefan Wagner

Axel Mahlberg

Burkhard Frank

Markus Bach

Eduard Fitz

Dieter Simmons

A self-propelled construction machine comprises a machine frame, at least three travelling devices, at least one hydraulic drive system for driving at least two travelling devices, wherein the hydraulic drive system comprises at least one controllable hydraulic motor with variable displacement volume and at least one hydraulic pump, at least one working device (e.g. a milling drum), for working the ground pavement. A detection device detects fluctuations in the longitudinal speed of the construction machine during movement thereof, wherein a control unit alters the displacement volume of the at least one controllable hydraulic motor as a function of the detected fluctuations so that the natural frequency of the hydraulic drive system is altered, wherein the control unit adjusts the discharge volume of the pump as a function of the amount of adjustment of the displacement volume in such a fashion that the specified drive speed remains constant.

Self-propelled construction machine and method for working ground pavements

The self-propelled construction machine according to the invention, in particular a road milling machine, stabiliser, recycler or surface miner, has a machine frame, a work roller arranged on the machine frame, and a left-hand edge protectorA arranged on the left-hand side of the work roller in the working direction and a right-hand edge protectorB arranged on the right-hand side of the work roller in the working direction. In order to raise and/or lower the left-hand and/or right-hand edge protectorA,B, a hydraulic system is provided which comprises a hydraulic sourcefor providing hydraulic fluid. The hydraulic system is characterised in that only a single main directional control valvewhich has three switch positions and is associated with a first and a second hydraulic cylinderA,B is provided, which main directional control valve interacts with a first auxiliary directional control valvewhich has two switch positions and is associated with the first hydraulic cylinderA, and with a second auxiliary directional control valvewhich has two switch positions and is associated with the second hydraulic cylinderB, in order to be able to raise and/or lower or floatingly mount the edge protectors.

Self-propelled construction machine

The invention relates to a road-building machine whose left front wheel () or caterpillar, right front wheel () or caterpillar, left rear wheel () or caterpillar and right rear wheel () or caterpillar are connected to the road-building machine chassis by means of an actuating element and are height-adjustable with respect to the road-building machine frame. According to said invention, different actuating elements are rigidly connected to the road-building machine chassis and forcedly coupled to each other in such a way that the left front wheel () or caterpillar and the right rear wheel () or caterpillar are height-adjustable in the same direction and with respect to the right front wheel () or caterpillar and the left rear wheel () or caterpillar are adjustable in the opposite directions. The all wheels () or caterpillars are equally height-adjustable. The inventive road-building machine provides a high operational stability, the improved compensation of the adjustment of lateral hindrance inclination of the road-building machine and the irregularities in the longitudinal direction thereof.

Road-building machine

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Asbach / Hussen, Germany

Markus Schäfer