| 摘要 |
PURPOSE:To decrease the loss of output torque during rotation and to prevent the injury of a second hand wheel even in the stage of pulling the second hand by controlling the axial movement of the second hand wheel by a step part near the axial center. CONSTITUTION:The axial movement of the second hand wheel 2 is controlled as the step part 21b of the wheel 2 is in contact with the step part 41b of a minute hand wheel 4. Since only the two step parts can contact with each other, the frictional force between the second hand wheel 2 and the minute hand wheel 4 is small and the loss of the output torque is small. The second hand arbor 21 moves in the stage of drawing the second hand 3 from the arbor 21; therefore the step part 21b thereof contacts with the step part 41b of the wheel 4, then the wheel 2 and the wheel 4 simultaneously move upward. The wheel 8 is similarly moved upward by a pinion 42 of the wheel 4 to compress a resetting spring 11. A contact surface 22a of a gear 22 of the wheel 2 moves upward by as much as a spacing V and contacts with the bottom surface of a center plate 5, by which the further upward movement of the wheel 2 is controlled. The second hand 3 is thus easily pulled with such contact state as the reaction. |
