| 摘要 |
<p>The device has a motor drivable drive wheel (120) alternatively brought from a resting position into an operating position. A spring unit (140) e.g. gas pressure spring, with a defined switching position is connected with the drive wheel and is formed to it to press the drive wheel in the operating position with a pre-determined contact pressure on a roadway (500). The spring unit is operatively connected with a switching mechanism, which enables locking of the spring unit and a release for driving the spring unit in the switching position of the spring unit.</p> |
