| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent engagement between a meshing tooth of a movable gear and a meshing tooth of a fixed gear from coming off by an excessive load or the like, without bringing weight- and space-increase. SOLUTION: A movable gear 8 provided oscillatably on an upper bracket 5 is pressed to a fixed gear 7 provided a lower bracket 4 to be meshed each other by a pressing member 12 moved by oscillation of a tilt lever 10. The gear 8 has an oscillation center in its base end portion, and a meshing tooth 8a meshed to a meshing tooth 7a of the fixed gear 7 in its tip portion. A portion to press the movable gear 8 by the pressing member 12 is set in the tip compared with a substantial central part in a meshing range between the meshing tooth 8a of the movable gear 8 and the meshing gear 7a of the fixed gear 7. |
