| 摘要 |
PURPOSE:To inhibit the erroneous detachment of an inside power supply, by providing a lock mechanism which hooks a data protecting inside power supply of a volatile memory when a power supply switch is turned off and then releases the hook state when the power supply switch is turned on, respectively. CONSTITUTION:When a power supply switch S1 is turned on, a commercial power supply 3 is connected to a power supply circuit 2. Thus the electric power is supplied to a volatile memory 4 from the circuit 2 via an electronic typewriter main body 1 and a changeover switch S2 interlocking the switch S1. When the S1 is off, the S2 connects an inside power supply pack to the memory 4 to supply the electric power to the memory 4 from an inside battery. Thus the data of the memory 4 is protected. In this case, an iron core 7A of an electromagnetic plunger 7 of a lock mechanism 6 hooking a power supply pack 5 is pulled down by a spring 8 to hook a battery power supply case 9. This process inhibits the detachment of the case 9. When the S1 is on, the electric power is supplied to the plunger 7 to separate the tip of the core 7A from the case 9. Thus it is possible to replace batteries while the power supply is applied to the memory 4. |
