| 摘要 |
The invention has an upper support (19) attached to the upper of the frame (11). A hand wheel is mounted on the upper support. Handles (23) are provided which drive the hand wheel and are manually actuatable by the driver. Gears (30) are mounted on the upper support. A loop (29) connects the hand wheel and the gears, whereby rotation of the hand wheel causes rotation of the gears. Locking devices are provided to detachably lock the hand wheel to the upper support so that the handle and the loop remain in fixed position. A gear (12b) is axially mounted on the front wheel. A chain (31) connects the gear to the gears whereby the gears are rotatable with the handle. |
