Patent GB-1196423-A (GB)
Title: Fire Alarm Systems for Buildings with Lockable Doors
IPC: E05B49/02
Filed: 1967-06-01
Abstract: 1,196,423. Fire alarms. HEIWA DENKI K.K. 1 June, 1967 [3 June, 1966], No. 25446/67. Heading G4N. [Also in Divisions E1-E2] A building includes a door having an electrically operable lock, a fire detecting device arranged and connected to operate a fire alarm, and also to affect an electrical circuit for the lock in such a manner that the door is unlocked, when fire is detected by the device, there being electrical switch means connected in the electrical circuit and selectively operable to effect the electrical circuit in such a manner that the door, if closed, is locked. As described the door is one of a plurality of such doors having electrically operable locks, and the fire detecting device is connected to affect electrical circuitry, including the electrical circuit, for the locks in such a manner that each door is unlocked at the same time, the electrical switch means being selectively operable to affect the electrical circuitry in such a manner that each door, if closed, is locked. Each electrically operated lock comprises an electromagnet 2 having a core 25, a pivotally mounted armature 26 which is pivoted into engagement with the core when the electromagnet is supplied with direct current, a fixed contact 34 and a slideable contact 33 in the circuit to the electromagnet, the contact 32 being moved into engagement with the contact 33 by closing the door to which the lock is fitted and the contact 32 being biased by spring 33 away from the contact 34, and a slidable bolt 30 which is biased by a spring 31 to the releasing position and which is held in the locking position by an arm 27 of the armature. When the other arm of the armature is attracted by the core of the electromagnet against the bias of a spring 29, the arm 27 is moved away from the bolt which therefore moves to the releasing position under the urge of the spring 31; when the armature is released by the electro-magnet the spring 29 restores it to its other position and the arm 27 engages the bolt and moves it to locking position. The attraction of the core for the armature is such that removing the direct energizing current does not release the armature, instead the armature must be supplied with an alternating current before it releases the armature. Fig. 1 shows the electrical circuitry, two of the electricallyoperated locks 2 1  and 2 2  being shown; each lock is connected to operating device 23 and an actuating device 11 which is actuated by a number of fire detectors 10 1 , 10 2  &c. and which rings an alarm bell 12 is also connected to the operating device 23. The operating device includes a number of three-position switches 31, 32 &c., one for each lock and considering the switch 31, the moving contact is connected to one terminal of the electromagnet in the associated lock, the other terminal of the electromagnet being connected via the contacts 32, 34 to earth. The fixed contact 31a of the switch 31 is connected to one terminal of a battery 5, the other terminal of which is connected to earth so that when the moving arm is on contact 31a and the door is closed the electromagnet of the lock 21 is energized and the bolt moved to the releasing position. The contact 31c is connected to one end of a secondary winding 18 of a transformer via a resister, the other end of the secondary winding being earthed so that when the moving arm of the switch 31 is on the contact 31c, alternating current is supplied to the electromagnet, provided the door is closed, and the armature is released so that the bolt is moved to locking position. The moving contact of each of the other switches is connected to its appropriate lock and the fixed contacts are similarly connected to the battery and the transformer. The remaining contact of each of the switches 31b, 32b, &c. is connected via the contacts of a relay 8 and a push-button switch 16 to a capacitor 9; when the relay 8 is unenergized, the contacts 31b, 32b, &c. are disconnected from the capacitor 9 and the capacitor is connected via the contacts 8c of the relay to a charging circuit for the battery, so that the capacitor is maintained in a charged state. When the relay is energized, the charging circuit for the capacitor 9 is disconnected and provided that the moving arm of each switch 31, 32 &c. is on the contact 31b, 32b &c. the electromagnets of the locks are connected to the capacitor which energizes them and so unlocks the doors. The relay 8 is energized from the battery 5 by one of the contacts 7 1  of the relay 7 when the relay 7 is energized. The relay 7 is energized from the battery 5 via contacts in the device 11 so that when any of the detectors is actuated by fire the relay 7 is actuated and hence actuates the relay 8 to unlock all the doors. The relay 7 has a holding contact 7 2  which by-passes the contacts in the device 11, a contact 7 3  which operates a lamp and a buzzer and a contact 7 4  which disconnects a common supply circuit for a plurality of indicator lamps 4 1 , 4 2  &c. The indicator lamps are connected to the contacts 31b, 32b &c., and are illuminated whenever the moving arms of the switches are on these contacts and the doors are closed and locked; the lamps are powered from a secondary winding of the transformer via a rectifier. A push-button switch 15 is provided which by-passes the contacts of the device 11, the switch when depressed energizing the relay 7 so that all the doors are unlocked. The push-button switch 16 referred to above, when depressed, releases the relay 7 and connects all the electromagnets of the locks to the secondary winding 18 of the transformer so that alternating current is supplied to the electromagnets to release the armatures and hence re-lock the doors.