| 摘要 |
<p>PURPOSE:To prevent environs from getting into trouble with an informing means unnecessarily acting by preventing it from acting in case of once removing a key to be again inserted even when an alarm is generated by inserting the key to a cylinder lock. CONSTITUTION:In a condition that a switch 11 is turned on with a key 2 inserted to a cylinder lock 1, when a door is opened turning on a switch 20, a timer 13 is driven, after its preset time, a relay 14 is actuated turning on switches 16, 17. Then simultaneously a relay A operates turning on its contact a1, so that a relay B operates turning on its contact b1 performing self hold. While simultaneously a contact b2 is turned on sounding a buzzer 18 informing of the key 2 forgotten to be removed. Here the key 2 is once removed, thereafter when it is again inserted, an output is generated from a counter 21 operating a relay C turning off its contact (c), consequently the buzzer 18 is stopped sounding.</p> |
