Patent GB-1310447-A (GB)
Title: Access control system for a closure means
IPC: G07C9/00
Filed: 1970-12-31
Abstract: 1310447 Releasable fastenings SARGENT & CO 31 Dec 1970 [31 Dec 1969] 62022/70 Heading E2A An access control system for a closure means, comprises a key, a mechanical lock 11 adapted to be operated by the key, key identifier means 9 for physically sensing information present in the key in the form of preselected surface contours thereof, electrical switch means within the key identifier for converting the information into switch states, computer means for comparing signals from the switch means with information previously supplied to the computer means, the computer means in use controlling electrical responsive means to permit entry through the closure means with operation of the mechanical lock by means of the key. As shown in Fig. 5 the lock 11 includes a cylinder lock mechanism having a barrel 20 which is rotatable by means of the key and to the rear of which a cam 19 is secured; the cam 19 when rotated by means of the key engages a bolt 13 to withdraw it from engagement with a striking plate 15; the electrical responsive means is a solenoid 17 contained in the housing of the cylinder lock mechanism and the armature 18 of which is normally disposed in a counterbore 19a in the cam 19 to prevent rotation of the cam and hence of the barrel; when the solenoid 17 is energised by a signal from the computer means the armature is retracted so that the barrel is free to be rotated by the key so that the cam can withdraw the bolt. In an alternative construction, not shown the electrical responsive means is separate from the mechanical lock and comprises a solenoid, the armature of which is connected through linkage to a bolt so that operation of the solenoid withdraws the bolt from the keeper against the resilience of a spring. Two forms of the key identifier means 9 are described, in the first, shown in Figs. 12 and 15, the identifier means comprises a key accepting cylinder 50 which is mounted on a plate 30 and passes through a block 39; the block 39 carries four switches 42 in radially extending channels 41 and a pin assembly 43 extends from each switch radially into block 39 and into the key accepting cylinder 50; the key is of the kind having six sides with pits in each side and the pin assemblies are disposed so that they engage four of the sides; the surfaces of the lower half of the key and the upper surface are those engaged by the pin assemblies of the identifier and the upper surfaces only are used by the mechanical lock. When the key is inserted into the identifier the uppermost switch 42 is operated first and turns on the computer means, the other switches are operated by the pits in the lower half of the key and as the key is inserted each pit causes its switch to produce an electrical pulse so that a sequence of pulses is sent to the computer means where those produced by the two side switches, which are coding pulses are stored in a transient holding stage; the pulses produced by the bottom switch are used to stop the transient holding stage so that it is ready to store the next pulses produced by the side switches; in a modification the first part of the bottom switch is used to switch-on the computer means and the top switch produces coding pulses which are also stored in the transient holding stage; when the key is fully inserted its tip closes a switch 42d which causes the transient holding stage to transfer the information read from the key into the computer memory where it is compared with the information stored in the memory anw, provided the key is correct, the signal is sent to the electrical responsive means so that it no longer prevents the closure means being opened. The front panel of the identifier contains two lamps one to indicate that power is on and the other which lights up when a correct key has been inserted and the electrical responsive means has been operated. A delay system is incorporated into the electrical circuitry to enable the key to be removed from the identifier and inserted into the mechanical lock before the solenoid of the electrical responsive means is switched off again. The pits in the key can be coded not only for releasing the solenoid but also to indicate to whom the key has been assigned and this information is transferred by the computer means to a print out device for permanent record including information as to the owner of the key, time of use, and whether the key has been accepted or not; the computer can also signal a guard station which can monitor a plurality of key identifier stations associated with a number of closures; the second key identifier is shown in Fig. 19 and differs from the first if that the key is inserted into a carrier 16 which is slidably mounted in a cylinder 61 the carrier being biased so that it normally protrudes from the front of the cylinder; the carrier has a centrally located keyway 62 and two oppositely disposed longitudinal slots 63 through which pin 43a of side switches 42a can engage the pits along the lower sides of the key; the upper switch 42 is again a start switch and when the carrier is in its normal position its pin assembly is engaged in a radially located opening 65 of the carrier so that as soon as the carrier is slid inwardly the pin is raised to operate the switch. The lowermost switch is engageable with a series of pits in the bottom of the carrier itself so that as the carrier is pushed in a series of pulses is produced by the lowermost switch to step the transient holding stage so that it can store the information received from the side switches step-by-step. When the carrier has been completely inserted a switch 42d is operated as before to cause the transient holding stage to transfer the information to the memory stage of the computer means 108 for comparison with the information stored therein and to cause the signal to be sent to operate the electrical responsive means if correct. Instead of using four switches, a switch for each position of the key where there can be a pit is provided and in such a case the information from the key is read when the key is fully inserted into the key slot; when this is done the transient holding stage is not required and instead the key identifier is connected directly to the memory stage 108 of the computer means where it is compared with the stored information.