Road building machine for milling road surfaces

A road building machine for road surface paving, comprising:

• an automotive travelling mechanism with a steerable front axle of the undercarriage comprising at least one support wheel and two rear support wheels;
• a working device which is mounted in or on the machine frame and is approximately flush with said machine frame on one side, said one side being a null side;
• a swivel unit having an articulation area formed by the machine frame and a swivel arm which carries the rear support wheel on the null side at its one end and is pivotably linked at its other end to the articulation area of the machine frame, with the swivel unit being arranged in the manner that it can be pivoted between an “outwardly pivoted position” in which the rear wheel which is on the null side is pivoted outwardly to an outer end position parallel to the longitudinal direction of the machine frame and an “inwardly pivoted position” in which the rear support wheel which is on the null side is inwardly pivoted to a parallel inward end position which is parallel to the longitudinal direction of the machine frame;
• and
• a pivot gear which controls the adjustment of the swivel unit between the “outwardly pivoted position” and the “inwardly pivoted position” around a swivel axis,
• wherein the pivot gear is a spatial gear, with a thrust member which is adjustable in the vertical direction, that comprises a deflection device which is arranged in a manner such that the deflection device deflects the vertical movement of the thrust member to a horizontal inwardly and outwardly pivoting movement of the swivel arm.