| 摘要 |
Wheels are utilized to effect movement of trolleys, wheelbarrows and the like, a greater force being required if they are to surmount a hinder. The object of this invention is to reduce the force required by replacing a wheel with a unit rotatable about an axle, a number of parts being arranged one after the other outside said unit, said parts being externally flat and rectangular, the part which is in contact with the ground surface remaining stationary during rotation of the unit, until the part in front of it comes into contact with the ground surface. |
