| 摘要 |
PURPOSE: To improve safety when a cart is used by providing a device to lock a wheel by a lock member connected to a wheel support part to be movable on two guide passages inclined in mutually facing directions when the cart is on an inclined surface. CONSTITUTION: As a cart is on an upward moving passage 24a, and when its inclination angle is an inclination angleαof a guide passage 11a or more, a ball 10a of a corresponding lock mechanism provided on the left side of a wheel gets out of a support body 12a by gravity to be engaged with a first notch on a ring 8a formed on a wheel disc 2 because the guide passage 11a is a little inclined backward and downward. This ball 10a remains as it is partially engaged in the guide passage 11a, so it acts as a stopper means for the next tooth 21a. The wheel is thus prohibited from rotating in a direction F1, and the cart is securely prevented from moving backward and downward, thereby it is kept on the moving passage 24a without moving.
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