| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a safe signboard which uses a small breaker having one electrode and yet can surely block the current of two electric wires on the occurrence of abnormal conditions. <P>SOLUTION: The signboard includes a boxlike case 1, and a freely openable door 2 provided on the front side of the case 1. The door 2 has a window part 3 capable of putting up a display object. Inside the case 1, a light source 4 irradiating the window part 3 with light from the backside is provided. The light source 4 is connected to a primary power source 5 via two electric wires L1 and L2. One electric wire L1 is provided with a breaker 6, and the other electric wire L2 is provided with a switch 7. The switch 7 is brought into a conduction state when the door 2 is closed, and brought into a non-conduction state when the door 2 is open. <P>COPYRIGHT: (C)2011,JPO&INPIT |
