1. Running wheel for overcoming stair steps, with five running rollers (10) which are combined into a rotating star (7) and are mounted rotatably on radial arms distributed at equal angular distances from one another, and of which, at any given time, two lower running rollers (L'u , Lu ) support the running wheel (5), when it runs on the plane surface and after each stair step has been overcome, on the tread surface (12, 13) of the latter, the running wheel (5), in order to overcome the stair step in the ascending direction, being pulled in the direction of ascent and, in order to overcome the stair step in the descending direction, is eased correspondingly in the opposite direction to the direction of ascent, characterised in that the radial arms and the running rollers (10) have such dimensions and are so assigned to one another that, in the said position of the running wheel (5) supported on two running rollers, the running-roller radius r, the distance a between the axis of the respective lower running roller (Lu ) facing the stair step and the bottom edge of the respective upper running roller Lo located above it, and the conventional rise height H of the stair step correspond to the relation 2r+a > H > r+9 so that, relative to a vertical line drawn through the point of contact between the upper running roller (Lo ) and stairstep edge located at the height H, the respective lower running roller (Lu ) located in front of the stair step projecting upwards is set back somewhat behind the respective running roller (Lo ) located above it, and, when the running wheel is pulled in the ascending direction, the said running roller (Lo ) located above strikes, by means of its half located below its axis of rotation, against the stair-step edge to be overcome and then lifts off the running roller (Lu ) located underneath it from the plane surface.
[German]
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