GB2151689A - Security device - Google Patents

Abstract

Security device e.g. for a door of a house or lock-up shop, comprises a housing (11) fixed to the door frame in use and a co-operating headed pin (15) fixed to the door edge which passes along an open ended slot (16) in the housing wall as the door is closed. A displaceable stop element (17) is movable within the housing and is provided with a slot (18) which holds the headed pin captive so preventing opening of the door when it is displaced to an operative position by an electric actuator comprising a motor (22), and gear unit driving an eccentric (21) which bears on the stop element. The device may be set after the door is closed and may incorporate or be connected to an alarm device. <IMAGE>

Description

SPECIFICATION Security device This invention relates to security devices for preventing or deterring unauthorised passage through or opening of a door, window, drawer or similar structure in which a hinged or sliding panel or other displaceable member is moved relative to a frame or other relatively fixed member for opening and closing the structure, said structures being hereinafter referred to as "openable structures".

The object of the invention is to provide a device which is compact, easily installed and maintained, and reliable in use; and which will provide substantial additional security when used in addition to conventional locks and fastenings and/or in conjunction with conventional electric alarm devices, particularly in preventing or deterring attemps to force an entry by the use of a jemmy or similar implement e.g. in the case of a lock-up shop door.

According to the invention there is provided a security device for an openable structure as defined hereinbefore comprising a fixture for mounting on one said member of the structure in proximity to a part of the other member which will move or be moved pastthe fixture during initial displacement of the displaceable member of the structure from its fully closed position; a stop element carried on the fixture and selectively moveable between a free position at which movement of the displaceable member is unobstructed by the device and an operative position at which said element lies in the path of said part of the other member or of a formation mounted on said part so as to allow only a very limited movement of the displaceable member from the closed position; and an actuating means for controlling movement of the stop member.

Preferably the fixture takes the form of a housing and the stop element takes the form of a plate within the housing operatively parallel to the path of said initial displacement and movable towards and away from said path so as to selectively engage and limit movement of a formation operatively mounted on said part of the other member so as to protrude into the housing during said movement in use.

Preferably the latter formation is a headed pin which passes along an open ended slot in a wall of the housing, being captured in a slot having a closed end in said plate when the latter is at the operative position.

The actuating means is conveniently electrically operated from a remote station so as to enable the device to be set or rendered inoperative by an authorised person, for example from the exterior of a building after a door fitted with the device has been closed.

The device may incorporate a built-in alarm andl or be connected to a remote alarm or other protective device which, when it is set, is actuated automatically if the stop element is abutted by said part of the other member or said formation.

One practical embodiment of the invention is now more particularly described by way of example as applied to an inwardly opening lock-up shop or house door with reference to the accompanying drawings, wherein: Figures 1 and 2 are perspective views of a security device showing respective operating positions of components thereof, Figure 3 is a perspective view of the device with parts broken away, Figure 4 is a detail view of a stop element of the device, and Figure 5 is a perspective view showing other components of the device.

A strong metal housing 11 having a removable cover (not shown) is operatively firmly screwed or bolted to the inside top frame of the door remote from its hinge so that a lower wall 12 is parallel to and in close proximity with part of the top edge of the door 13 during initial movement of the latter from the closed position. A metal plate 14 (Figures 1 and 2) is screwed to said part of the door edge and carries an upwardly projecting headed metal pin 15 which enters and passes freely along an open ended slot 16 in wall 12.

Within the lower centre part of housing 11 is a strong box-like sheet metal stop element 17 the bottom of which is a plate having a slot 18 (best shown in Figure 4) which is open ended at the end nearest the door frame but whose opposite end is closed, i.e. this slot does not continue to the edge of the plate remote therefrom. The width of slot 18 is sufficient to clear the shank of pin 15 but is not sufficient to allow its head to pass therethrough.

Element 17 is suspended in housing 11 by four tension springs 19 (Figure 5) one at each corner which resiliently urge it upwards away from wall 12 and is guided by a pair of internal partitions 26 in spaced parallel relationship extending between the front and rear walls. Clearance is allowed for element 17 to "float" to a limited extent both laterally and forwards and backwards in the housing.

A shaft 20 is journalled transversely above element 17 in partitions 26 and carries an eccentric 21 which bears on the top of element 17 and is actuated by a miniature 12 v. a.c. motor 22 driving through a high ratio speed reducing gear box integral with the motor unit and mounted on one of the partitions 26.

Preferably the power supply to motor 22 is derived from a battery (not shown) which is continuously trickle charged from the main supply so that operation of the device is independent of temporary power failures, current from the battery being supplied through a d.c. to a.c. converter. The a.c. motor is preferred because its high impedance resists burning out the windings if its operation is obstructed e.g. if an attempt is made to operate it with the door part open so that movement of element 17 is prevented by the presence of the pin 15 in slot 16. If motor 22 is so stalled it will "chatter" providing audible warning of the obstruction.

In use door 13 will be closed and locked in the normal way, and the device will be set from outside by a key actuated switch or other secure means at a remote station connected electrically to the device to bring motor 22 into operation so as to rotate eccentric 21 and move element 17 downwards from the position illustrated in Figure 1 to that shown in Figure 2. When this position is reached micro switch 25 cuts off motor 22 and element 17 is effectively locked at this position as the high ratio gear box 23 prevents rotation of shaft 20 even if any attempt is made to force element 17 upwards. Preferably control cam 24 is timed to cut out motor 22 when the eccentric 21 is at bottom dead centre, thus providing additional security against any attempt to force element 17 upwards. This is all that is necessary to setthe device.An attemptto force the door, for example by using a jemmy to lever it sufficiently to break the mounting of its conventional locks, will cause itto open an inch ortwo until headed pin 15 has travelled along the slot 18 in element 17 and reached its blind outer end. The door is then strongly held by engagement of said headed pin in element 17 which, in turn, is heid within housing 11 and further effective use of the jemmy is difficult or impossible as the door is now at a position where sufficient leverage cannot be easily obtained.

At the same time the attempted opening will displace element 17 forward slightly in housing 11 causing an alarm switch (not shown) to be actuated and a built in siren (not shown) powered from the battery to sound. The alarm switch may also actuate other alarm circuits for operation of a conventional burglar alarm and transmission of a signal to local Police or security services, and/or operation of other security devices e.g. a flashing light outside the building.

The sounding of the siren coupled with the intruder's failure to get the door open at the first attack will, it is believed, often be sufficient to deter any further attempt particularly as the shape of plate 14 (which hooks over the edge of the door) and the very strong engagement of headed pin 15 within the other parts of the device strongly attached to the door frame makes it unlikely that the door could easily be further forced.

The device is simply returned to its inoperative condition by the authorised user switching to deactivate at the remote station so deactivating the alarm circuits and connecting motor 22 to rotate shaft 20 and allow element 17 to rise to its Figure 1 position, motor 22 then being switched off by the cam actuation of switch 25 once more.

It will be appreciated that the device can be employed in a number of ways, for example housing 11 might be mounted on the door itself for cooperation with a headed pin attached to the frame (e.g. in the case of an outward opening door) or the device can be used on windows, sliding doors, cupboards, and cash tills, safes, or drawers. It can be used in the manner of a door chain by being set from within a building so that it permits limited opening of the door sufficient for an occupant to verify the identity of a caller etc., and could also be used in jewellers shops, banks etc. to speedily secure a door against being opened if there is an attempt at internal robbery.

For added security two or more of the devices, interconnected electrically to operate in common, may be used e.g. near the top and bottom of a large door.

Claims (13)

1. A security device for an openable structure as defined hereinbefore comprising a fixture for mounting on one said member of the structure in proximity to a part of the other member which will move or be moved past the fixture during initial displacement of the displaceable member of the structure from its fully closed position; a stop element carried on the fixture and selectively moveable between a free position at which movement of the displaceable member is unobstructed by the device and an operative position at which said element lies in the path of said part of the other member or of a formation mounted on said part so as to allow only a very limited movement of the displaceable member from the closed position; and an actuating means for controlling movement of the stop member.

2. A device as in Claim 1 wherein the fixture takes the form of a housing and the stop element takes the form of a plate within the housing operatively parallel to the path of said initial displacement and movable towards and away from said path so as to selectively engage and limit movement of a formation operatively mounted on said part of the other member so as to protrude into the housing during said movement in use.

3. A device as in Claim 2 wherein said formation is a headed pin which passes along an open ended slot in a wall ofthe housing, being captured in a slot having a closed end in said plate when the latter is as the operative position.

4. A device as in any preceding claim wherein the actuating means is electrically operated from a remote station so as to enable the device to be set or rendered inoperative by an authorised person.

5. A device as in any preceding claim including a built-in alarm which, when it is set, is actuated automatically if the stop element is abutted by said part of the other member or said formation.

6. A device as in any preceding claim including means for connection to a remote alarm or other protective device which, when it is set, is actuated automatically in use if the stop element is abutted by said part of the other member or said formation.

7. Device as in any preceding claim wherein the stop element is resiliently urged to the free position, the actuating means including a selectively movable camming element acting on the stop element to drive it positively to and retain it at the operative position.

8. A device as in Claim 7 wherein the camming element is a rotatably driven eccentric.

9. A device as in Claim 8 wherein when a stop element is at the operative position the eccentric is angularly positioned at dead centre with respect to said element.

10. A device as in Claim 7,8 or 9 wherein the camming element is driven by an electric motor through a high ratio speed reducing gear box.

11. A device as in Claim 10 wherein the motor is an a.c. motor.

12. A device as in Claim 11 including a d.c. to a.c.

converter for powering the motor, a rechargeable battery, and trickle charging means for the battery.

13. A security device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.