| 摘要 |
A toy vehicle wheel that changes from a generally cylindrical periphery with an initial diameter and axial width to a greater diameter periphery. The wheel has a hollow shell of rubber or some other flexible material and opposed sidewalls of the wheel are moveable relative to each other to compress the axial width and increase the diameter. Across a substantial portion of the initial axial width a number of slits extend so that the periphery is serrated when it is enlarged. In one form, an axial screw engages a sidewall to rotate the wheel in its initial quiescent condition along a relatively unobstructed surface, but, upon encountering an obstruction, will draw the one sidewall toward the other. Variations provide for containing the axial screw within the compressed wheel or permitting it to extend out of a sidewall. Other forms provide for movement of the sidewalls relative to each other with bayonet locking in a desired condition and for spring bias in one direction. |
