To provide a shutter device which automatically sets its shutter curtain in a fully closed state, when an opening force for opening the shutter curtain or a halting force for halting the shutter curtain at a location other than a fully closed location is canceled, while dispensing with a special device or a special mechanism as much as possible.
The shutter device is formed of a take-up shaft 34, the shutter curtain 30, and a return coil spring for storing therein a return spring force upon the rotation of the take-up shaft 34, at the unwinding of the shutter curtain. According to the shutter device, a torque T1 about the take-up body 34, generated by the return spring force of the return coil spring, is set smaller than a torque T2 about the take-up body 34 generated by a downward closing force of the shutter curtain 30 due to the self-weight W of the same, and therefore the shutter curtain 30 which is in the process of opening operation is returned to the fully closed location due to its self-weight.
NODA TAKASHI
KUMAGAI NAOTO
Hironari Nakano