Patent GB-1373281-A (GB)
Title: Security system
IPC: G07C9/00
Filed: 1972-04-04
Abstract: 1373281 Locks AMERICAN DISTRICT TELEGRAPH CO 4 April 1972 [5 April 1971] 15435/72 Heading E2A A security system for remotely unlocking the individual doors of, for instance, a motel when a correct key is inserted into a keysensor 16 at the door, comprises a scanning multiplex system for checking each door keyreceiver against a corresponding key or keys at a control panel 20, and if it matches, sending an unlocking signal to the door. The scanning is done by a station address generator 42 including a multiplexing switch 41, and a phase address system 42A which includes gauged multiplexing switches 41A, and the key in each local key-port 16 is compared sequentially with the key (if any) in key-sensors (36), 38, 40 and 44 for various authorised persons, and if the inserted key agrees with any of these, a Data Compare Station 56 sends an unlocking signal to the appropriate lock 30. A spurious key will give an alarm at 46. When the room is ready to be used, a maid closes switch 48 in the room, to give a signal at 50 to this effect until switch 49 at the control panel is operated. The door will be unlocked when a connectedly coded patron's key is used or when master keys used by maids, maintenence men or managers, are inserted, corresponding to keys in the control panel key sensors 44, 40, 38 or 36. A detailed circuitry of the control panel station 18 and the monitor station 26 at each door is shown in Fig. 2. Key code data from station 16 passes through data gate 34 to comparator 56 where it is compared with a succession of selected codes from the keysensors of the control panel. A correspondence causes data to pass to gate 64 and back through gate 34 to the lock bolt operator 70 feeding retraction solenoid 72. An incorrect key causes the gate 64 to activate the alarm at 46. The station address and timing generator 42 feeds a multi-address receiver and decoder 58 connected to the control panel key sensors. The keys are cards made of disposable material punched to a code by means of punches randomly placed on the card by a random noise generator (Fig. 4, not shown) operating through a series of solenoids and cam-operated punches, two matching cards being punched simultaneously (Figs. 5 and 6, not shown). The cards may be of plastics or metal. Figure 9a shows such card, but one edge may, instead, be notched (Fig. 9b, not shown) or the key may be cut into steps (Fig. 9c, not shown) or tabs on the opposite sides (Fig. 9d, not shown) may be used. The key sensors may be metal pins, magnetic means, or photo-sensors. As shown in Figs. 7 and 8 (not shown) pairs of metal spring fingers make contact through holes in the cards. The lock, Figs. 13, 14, 15, comprises a main bolt 152 and an auxiliary anti-tampering bolt 154 acting as a night latch, both engaging the same striking plate, but the bolt 154 is interconnected to the main bolt in such a way that it has to be extended to release from the striking plate. The door is locked by a lever 156 which prevents extension of this auxiliary bolt until it is freed from pawl 160 by electromagnet 166. The door may be opened from the inside by handle 167 turning the pawl 160 to the releasing position. It is described, (Fig. 16 and 17, not shown) how the electromagnet may be disposed over the locking lever to conserve space. In the form shown in Figs. 19 and 20, the door latch bolt 222 engages a strike-latch 228 pivoted at 234 in the door jamb which is released by electromagnet 254. The strike latch is biassed to its fastening position by spring 236. Energisation of electromagnet 254 causes plunger 256 to turn lever 260 about its pivot 262 to pull back a slider 266 to pull back a pivoted flap 252 to free a latch stop 238 to unlock the strike plate 228 which controls the strike latch which can then be rotated to releasing position by pressure on the door. In an alternative arrangement (Figs. 28-34, not shown) similar lock components are somewhat rearranged to conserve lateral space.