| 摘要 |
PURPOSE:To quickly increase the torque of a spiral spring when the turning moment of a driven member is at its peak, by changing the second moment of the cross-sectional area lengthwise and fixing an end, whichever the second moment is larger, as an inner side to a mandrel. CONSTITUTION:A spiral spring 1 has an inner end hook 1a to be engaged with a split groove 2a formed on a mandrel 2 which is held swivel and an outer end hook 1b to be fixed to a suitable fixing member (not shown in the figure), and the portion between both ends is composed of a narror section 1c and wide section 1d for example, by changing the width of the spring 1 stepwise. The secondary cross- sectional moment of the spring is larger at the inner end compared with that at the outer end, which provides the spring with nonlinear characteristics. A mechanism equipped with this spring for providing turning moment is used, for example, for an automobile trunk lid to provide ideal open-close control. |
