| 摘要 |
PURPOSE:To prevent invasion of a foreign matter into a wheel transmission mechanism by providing a truck with a fan-shaped opening which allows turning of the wheel and projecting the wheel downward from said opening and further providing a coverage on the opening. CONSTITUTION:An opening 11 is provided on a truck 1 and a fan-shaped cover 12, with a wheel turning shaft as its center, is combined with said shaft 10 so as to cover the opening 11. The radius of a circumference is formed larger than that of the opening 11 and an opening 13 is provided for projection of the wheel 2. Further, a fan-shaped angle theta1 is set larger than the total value of an angle theta2 of the opening 11 and the value twice as much as an angle theta3 of possible turning. Thus, invasion of a foreign matter into a wheel transmission mechanism can be prevented. |
