| 摘要 |
PURPOSE:To reduce the quantity of parts and ensure a compact design by providing a bobbin having a cylindrical shape so supported as to be capable of free rotation and a strip shaped coil spring wound about the periphery thereof in such a way as to be freely rewound. CONSTITUTION:A strip-shaped coil spring 2 is wound about the periphery of a cylindrical bobbin 1 having an actual center O, thereby constituting a constant load spiral spring mechanism. The rotational center O1 of the bobbin 1 is located at a point off the actual center O of the bobbin 1 by an eccentricity amount. The diameter of the bobbin 1 is determined to a desired size and the eccentricity of the rotational center O1 thereof from the actual center O of the bobbin 1 is pertinently selected, thereby enabling the determination of a stop position due to exact balance at a desired position. According to the aforesaid construction, the quantity of parts is reduced and the mechanism can be made compact. |
