GB2288427A

GB2288427A - Security locking device

Info

Publication number: GB2288427A
Application number: GB9407381A
Authority: GB
Inventors: Joseph Patrick Nevin
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-04-14
Filing date: 1994-04-14
Publication date: 1995-10-18
Anticipated expiration: 2014-04-14
Also published as: GB9407381D0; GB2288427B

Abstract

A cylinder-type lock has sensors (for example proximity sensors) 20 mounted above tumblers 17, the outputs of the sensors being connected to a microprocessor (not shown). The correct key 30 produces a specific pattern of signals from the sensors 20 as it is inserted into the passageway 16 due to its distinct profile, and this pattern of signals is compared with a pattern preprogrammed into the microprocessor, to produce an output only if the two patterns of signals agree. The output of the microprocessor may, for example, be connected to an alarm system which is normally activated, but which is de-activated in response to an output from the microprocessor. Thus, even if the lock is picked or forced, the microprocessor will not product an output and the alarm will therefore remain activated such that it sounds when the door in which the lock is mounted is opened. Disk tumbler arrangements may be employed and the output can be used to disable a vehicle ignition. <IMAGE>

Description

Security Locking Device This invention relates to a security locking device for preventing unauthorised access to vehicles or buildings.

Cylinder-type locks are widely used to prevent unauthorised access to vehicles or buildings. Cylinder locks comprise a barrel or cylinder rotatably mounted in a housing.

When locked, a plurality of tumblers slidably mounted in the housing are biassed into apertures in the cylinder, thereby preventing the latter from rotating in the housing. When a key is inserted into a slot which extends axially along the cylinders, the tumblers are raised. The tumblers comprise separate upper and lower portions, so that when the correct key is inserted the join between the two portions lies flush with the outer surface of the cylinder, so that the cylinder is free to rotate when the key is turned. The cylinder is connected to a locking mechanism which releases when the cylinder is turned.

If an incorrect key is inserted, the tumblers do not align properly and the cylinder cannot be rotated. However, it is relatively easy for an experienced thief to pick or force a cylinder lock.

I have now devised a security locking device which is more secure than conventional cylinder locks.

In accordance with this invention, there is provided a security locking device comprising a housing, a rotatable element mounted in the housing and having an axially extending passageway for receiving a key, a plurality of movable tumblers arranged on a line which extends longitudinally of the rotatable element, a portion of the tumblers projecting into the passageway, the tumblers being arranged to lock the casing to the rotatable element so as to prevent rotation of the latter until a correct key is inserted, and sensors arranged to give outputs according to the positions of the movable tumblers, the outputs from the sensors being connected to a detector means which compares the pattern of signals provided by the sensors when a key is inserted into the passageway with a stored pattern of signals representing the pattern of signals which should be provided when the correct key is inserted, the detector means providing an output signal when the two patterns of signals compare.

The output from the detector means may be connected to a secondary locking device, an alarm or means for disabling the object which has locked. Thus, if a thief picks or forces the lock he will not generate the required pattern of signals to unlock the secondary locking device, deactivate the alarm or enable the object which has been locked.

Preferably the sensors output signals representing binary 0 and 1, depending on the position of their respective movable tumblers.

Preferably the tumblers comprise pins or discs biassed into the passageway.

Preferably tumblers project into the passageway from opposite sides.

Preferably the sensors comprise proximity sensors directed at the tumblers.

An embodiment of this invention will now be described by way of example only, and with reference to the accompanying drawing, the single figure of which is a sectional view of a security locking device for a vehicle in accordance with this invention.

Referring to the drawing, there is shown a security locking device fitted to the inside of a door panel 10 of a vehicle. The device comprises a housing 11 and a rotatable cylinder 12 mounted inside the housing. An externally screwthreaded shaft 13 is attached to one end of the cylinder 12 and projects through an aperture in the housing 11. A lever 14 is keyed onto the shaft 13, and a nut 15 prevents the lever from becoming detached from the shaft. The opposite end of cylinder 12 projects through the aperture in the door panel 10. A key passageway 16 extends axially along the cylinder 12 from the outside of the door panel. A plurality of movable pin tumblers 17 of different lengths, and comprising inner and outer portions 17a,17b, project radially into the passageway 16 from opposite sides.The tumblers 17 are mounted in bores 18 which extend through the wall of the cylinder 12 and into the casing 11. Springs 19 are arranged in each bore 18 to bias the tumblers 17 into the passageway 16. A sensor 20 is arranged in each of the bores 18 in the housing 11. The sensors 20 are connected to a microprocessor (not shown) via a cable 21.

When there is no key in the passageway 16, as shown in the drawing, the outer portions 17b of the tumblers extend between the housing 11 and the cylinder 12. Thus, the cylinder 12 cannot be rotated to actuate the lever 14.

When a serrated key 30 is inserted into the passageway, the tumblers 17 rise and fall as their radially inner ends ride over the serrations in the key. When the tumblers 17 rise the output signals from their respective sensors change state.

Thus, as the key 30 is inserted, the output from each sensor 20 changes state several times until the key is fully inserted.

This pattern of signals will be different if the incorrect key is inserted. The microprocessor is preprogrammed with the pattern of signals which should be obtained when the correct key is inserted. This pattern may be programmed in the factory by entering data corresponding to the profile of key, alternatively it could be programmed by placing the microprocessor in a learn mode and inserting the correct key into the locking device, whereupon the microprocessor stores the patterns of signals generated.

When the correct key is inserted an output from the microprocessor changes state, say to disable an alarm or to activate the vehicle's ignition system. The profile of the correct key raises the tumblers 17, so that the join between their inner and outer portions (17a,17b) lies flush with the outer surface of the cylinder. The two portions of the tumblers (17a,17b) are separable, so that the cylinder 12 is free to rotate and actuate the lever 14 when the key 30 is turned. If the wrong key is inserted, it will not raise all or some of the tumblers to the correct position, and the cylinder 12 cannot be rotated.

If a thief picks or forces the lock, he will be able to gain access to the vehicle. However, any such entry would not generate the correct or any pattern of signals from the sensors 20. Thus, an alarm may be triggered, and the thief will not be able to steal the vehicle since its ignition remains disabled.

The locking device may alternatively be connected to a secondary locking device which remains locked unless the correct pattern of signals is generated. It will be appreciated that the locking device may be used in any situation where key access to property is required, such a vehicles, buildings, computers and machinery.

Claims

1) A security locking device comprising a housing, a rotatable element mounted in the housing and having an axially extending passageway for receiving a key, a plurality of movable tumblers arranged on a line which extends longitudinally of the rotatable element, a portion of the tumblers projecting into the passageway, the tumblers being arranged to lock the housing to the rotatable element so as to prevent rotation of the latter until a correct key is inserted, and sensors arranged to give outputs according to the positions of the movable tumblers, the outputs from the sensors being connected to a detector means which compares the pattern of signals provided by the sensors when a key is inserted into the passageway with a stored pattern of signals representing the pattern of signals which should be provided when the correct key is inserted, the detector means providing an output signal when the two patterns of signals compare.

2) A security locking device as claimed in claim 1, wherein the output of the detector means is connected to a secondary locking device which is arranged to unlock in response to an output from the detector means.

3) A security locking device as claimed in claim 1, wherein the output of the detector means is connected to an alarm which is arranged to be deactivated in response to an output from the detector means.

4) A security locking device as claimed in claim 1, wherein the output of the detector means is connected to mains for disabling the object which has locked, the disabling means being arranged to be enabled in response to an output from the detector means.

5) A security locking device as claimed in any preceding claim, wherein the sensors output signals represent binary 0 and 1, depending in the position of their respective movable tumblers.

6) A security locking device as claimed in any preceding claim, wherein the tumblers comprise pins biased into the passageway.

7) A security locking device as claimed in any preceding claim, wherein the tumblers comprise discs biased into the passageway.

8) A security locking device as claimed in any preceding claim, wherein the tumblers project into the passageway from opposite sides.

9) A security locking device as claimed in any preceding claim, wherein the sensors comprise proximity sensors directed at the tumblers.

10) A security locking device substantially as herein described with reference to the accompanying drawing.