| 摘要 |
The invention relates to a mobile device, comprising a frame and at least two wheels which are coupled in a freely rotatable manner to the said frame by means of respective rotary bearings. The mobile device according to the invention has the particular feature that the rotary bearing of at least one wheel is of the type which can rotate in one direction of rotation and is blocked against rotation in the other direction, in such a manner that the wheel in question can only roll in one direction.
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