BACKGROUND TO THE INVENTION Increasing crime rates make it desirable to secure premises against unauthorized entry. Conventionally this is done by closing and locking all doors and windows. However, burglars are adept at picking locks and even if they do not have the skills necessary to enter premises in this way, brute force to break locks or window panes ensures unauthorized entry.

Many premises are protected by an alarm system which is triggered upon a window or door being opened. However, by the time the alarm system has been activated, access has been gained to the premises and the burglar will normally delay his escape for long enough to grab whatever valuables or saleable goods are to hand.

The present invention seeks to provide a security device which will inhibit unauthorized entry to premises. It also seeks to provide a security installation which will establish an alarm condition before entry is gained to the premises and which will continue to inhibit entry after establishing an alarm condition.

BRIEF DESCRIPTION OF THE INVENTION According to a first aspect of the present invention there is provided a security device for preventing opening of a door or window of premises comprising a hollow sleeve of circular cross section for insertion into a socket in a surface over which the door or window passes during opening and which socket is inaccessible from outside the premises, and a stop element having a spigot of circular cross section for insertion into said sleeve, the stop element further having a head of circular cross section which is of greater diameter than the spigot, the stop element, once in the sleeve, protruding from the sleeve and lying in the path of travel of said door or window and inhibiting movement thereof.

According to a second aspect of the present invention there is provided a security device for preventing opening of a door or window of premises comprising a sleeve for insertion into a socket in a surface over which the door or window passes during opening, a stop element for insertion into said sleeve, the stop element, once in the sleeve, protruding from the sleeve and lying in the path of travel of said door or window and preventing movement thereof, and means operable from a location remote from said device for locking said stop element to said sleeve and for releasing said stop element from the sleeve.

In one form the device includes an infrared receiver for receiving lock and unlock signals. In another form the device includes a radio receiver for receiving lock and unlock signals.

In the preferred form said sleeve is cylindrical and open at least at one end, and said element includes a spigot which fits into said sleeve and a head at one end of the spigot, the transverse dimensions of the head being greater than those of the spigot.

According to a third aspect of the present invention there is provided, in combination; a security device comprising a sleeve and a stop element, the sleeve being for mounting in a socket in a surface over which the door or window passes during opening and which socket is inaccessible from outside the premises and the stop element being for insertion into said sleeve, the stop element, once in the sleeve, protruding from the sleeve and lying in the path of travel of said door or window and preventing movement thereof; a switch for mounting on said door or window so that it encounters said element upon the door or window being moved in the opening direction; and an audible and/or visual alarm means which is activated upon said switch being operated by said element during attempted door or window opening.

In one form said switch and said alarm means form part of a unit which can be mounted on said door or window. In another form said switch and a signal transmitter form part of a first unit which can be mounted on the door or window, said alarm means and a signal receiver being contained within a housing forming a second unit that can be mounted at a location remote from said first unit.

According to a fourth aspect of the present invention there is provided a security installation comprising a sleeve mounted in a socket in a surface over which the door or window passes during opening and which socket is inaccessible from outside the premises, a stop element for insertion into said sleeve, the stop element, once in the sleeve, protruding from the sleeve and lying in the path of travel of said door or window and preventing movement thereof, a switch mounted on said door or window so that it encounters said element upon the door or window being moved in the opening direction, and an audible and/or visual alarm means which is activated upon said switch being operated by said element during attempted door or window opening.

Said switch can be a mechanical switch operated by pressure exerted thereon when the door or window is forced against said element. Alternatively said switch can be a proximity sensor.

According to a fifth aspect of the present invention there is provided a security device for preventing opening of a door or window, the device comprising a first component in the form of a casing for mounting in a socket in a surface over which a door or window moves during opening, the casing containing a battery and a sounder for providing an audible alarm and a second component including a spigot which can be inserted into the first component, the second component, once in the first component, protruding from the first component and lying in the path of travel of said door or window and inhibiting movement thereof, the device including switch

means operable upon the door or window being moved in the opening direction to activate said sounder.

This device preferably includes locking means operable from a location remote from said device for locking said first and second components to one another to prevent removal of said second component from said first component and for releasing said components from one another to permit removal of said second component from first component.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:- Figure 1 is a pictorial view of a first form of security device in accordance with the present invention; Figure 2 is a section showing the security device of Figure 1 in use; Figure 3 is a pictorial view illustrating a security system which includes an audible or visual alarm; Figure 4 is a section through a further security device which incorporates an audible alarm; Figure 5 is a section through a further security device.

DETAILED DESCRIPTION OF THE DRAWINGS The security device 10 shown in Figure 1 comprises first and second components 12 and 14.

The component 12 has a solid spigot 16 of circular cross section and a solid head 18 which is also of circular cross section and of greater diameter than the spigot 16. The spigot 16 and head 18 are coaxial.

The component 14 is in the form of a hollow sleeve 20 with a circular flange 22 at one end. The inside diameter of the sleeve 20 is such that the spigot 16 can be inserted, with an amount of free play to make insertion effortless, into the sleeve 20 from the end at which the flange 22 is located. Once the spigot is inserted into the sleeve, the underside of the head 18 rests on the flange 22.

The security device 10 is used by mounting the component 14 in a socket 24 provided therefor in a floor F. The socket can have an epoxy based adhesive therein to hold the component in place. The flange 22 can lie on the surface of the floor as shown or in a circular depression (not shown) which surrounds the socket 24. In this form the top face of the flange 22 lies flush with the floor. The socket 24 is provided in a position such that door D (or window) being swung or slid towards its open position as shown by arrow A in Figure 2 passes freely over the socket 24 and over the component 14 which is in the socket.

The socket 24 can be drilled in the floor in retrofit situations or the component 14 can be embedded in the wet concrete of the floor if fitted during construction.

When the spigot 16 of the component 12 is inserted into the sleeve 20 5 from above, the head 18 protrudes above floor level. Hence, as the door or window is swung or slid open as shown by arrow A, it encounters the head 18 and further movement thereof is prevented.

The socket can be close to the door or window when the door or window is closed whereby the head 18 prevents any movement whatsoever of the 10 door or window. Alternatively it can be spaced from the closed door or window so that a small amount of movement is permitted before the door or window impacts on the head 18.

The security system of Figure 3 comprises a security device 10 as shown in Figures 1 and 2 and a unit 26 which is secured to a door D. The door D 15 (the lower part of which is shown) is secured by hinges H to a post P. In its simplest form the unit 26 comprises a casing 28 in which there is housed a battery 30 and a audible alarm 32. The alarm 32 is preferably a piezo electric sounder. Externally of the casing 28 there is a switch 34. The switch 34 is preferably a mechanical switch embedded in rubber or a similar compound so that substantial pressure has to be 20 exerted on the switch 34 before it activates. The switch 34 could, however, be a

proximity switch as described in more detail hereinafter. The switch 34 is positioned so that it encounters the head 18 as the door or window is opened as shown by arrow B. Upon sufficient pressure being exerted on the switch 34 by the door as the person trying to enter the premises in an unauthorized manner pushes on it, the switch 34 closes and the alarm 32 is activated.

There can be a holding circuit for maintaining the alarm 32 activated even if pressure on the switch 34 ceases when the door is released. The holding circuit in a simple form comprises a small solenoid which is itself energised when the switch 34 closes. This closes a set of solenoid contacts which are in parallel with the switch 34 and in series with the sounder 32. Thus even when the switch 34 opens there is a closed circuit through the solenoid's contacts and the sounder. The set of solenoid contacts can either be opened manually to shut-off the alarm or alternatively a manually operable normally closed switch, in series with both the switch 34 and the solenoid's set of contacts, can be provided. A reset button 36 for temporarily opening this switch to de-energize the solenoid and deactivate the alarm is shown protruding from the casing 28.

In another form the alarm 32 is not in the casing 28 but at a remote location. It can be, for example, the alarm of a burglar alarm system fitted to the premises. The unit 26 in this form includes a radio transmitter. The corresponding radio receiver is mounted on a wall or ceiling and connected into the burglar alarm system so that the burglar alarm system is activated upon the receiver receiving a radio signal from the unit 26. Provided the unit 26 and receiver can be mounted in a line of sight relationship, an infrared link can be used instead of a radio link.

Turning now to Figure 4, the security device illustrated is designated 38 and again comprises two components 40 and 42 similar to, but larger than, the 5 components 12 and 14.

The component 40 includes a cylindrical casing 44 which forms a housing for a battery 46 and a sounder 48. Two circular contacts 50 enable the circuitry in the component 40 to be connected to a switch 52 of the component 42.

The housing 40 is closed at its upper end by an end plate 54. A 10 central hollow sleeve 56 extends downwards from the end plate 54 and, in use, receives a spigot 58 of the component 42. The end plate 54 and sleeve 56 are removable to permit access to the battery 46. The component 42 has a head 60 which is larger than the spigot 58, the switch 52 being mounted in a recess in the periphery of the head 60.

15 The switch 52 can be a proximity sensor such as a Hall effect switch or a reed switch, or can be a mechanical switch similar to the switch 34. Leads 62 extend from the switch 52 to two circular contacts 64 at the lower end of the spigot 56.

The component 40 of the security device 38 is mounted in a floor socket in the same way as the component 12 of the security device 10. When the spigot 58 of the component 42 is dropped into the sleeve 56, the contacts 64 come to rest on the contacts 50.

The security device 40 includes a holding circuit (not shown) for the sounder 48. This circuit is preferably electronic rather than electromechanical because of the space constraints but operates in the same way as the holding circuit described above in relation to Figure 3.

The door or window carries a magnet or a metal plate if the switch 52 is a reed switch or a Hall effect switch. If the switch 52 is of the same mechanical type as the switch 34, then nothing need be attached to the door or window.

When the switch 52 closes upon pressure being exerted upon it, or upon the magnet or metal plate on the door or window coming into close proximity to it, the sounder 48 is activated and remains activated until manually switched off by means of the reset button. In this form the reset button can protrude from the top face of the head 60.

It will be understood that the security devices described thus far must all be used inside the premises being protected as they are rendered inoperative by removing the component 12 or 42 from the component 14 or 40.

If the device is to be used on, for example, a sliding door where the moving door is outside the fixed door when the sliding door is open, or on a swinging door which opens outwardly, a device with locking means is required. The locking means, until released, secures the components 12 and 14 or 40 and 42 together. In 5 the preferred form the device with locking means includes a radio frequency or infrared receiver. The corresponding transmitter is carried by an authorized person.

When the transmitter is activated the device is locked and when the transmitter is next activated the device is unlocked.

Turning now to Figure 5 this illustrates a form of security device that 10 can be used on the outside of premises. The securing device illustrated is generally designated 66 and comprises a stop 68 which is hinged at 70 to the upper edge of an open topped housing 72. The housing is embedded in a floor 74. The stop 68 includes a depending wall 76 and a top plate 78 which forms a closure for the housing 72 when the stop 68 is depressed.

15 A battery 80 and a radio receiver 82 are provided in the housing 72. A first solenoid 84 has its core connected by a rod 86 to the underside of the plate 78.

A spring 88 acts between the body of the solenoid 84 and the underside of the plate 78.

A second solenoid 90 is provided for operating a latch 92 which moves 20 in guides 94. The core of the solenoid 90 is connected by a rod 96 to the latch 92.

A return spring 98 is provided for urging the latch 92 to its forward position.

The wall 76 has a hole 100 in it which co-operates with the latch 92.

The device 66 is shown in its operative condition in Figure 5 and prevents the door D from moving to the right, that is, towards its open position. The plate 78 cannot be depressed because the stop 76 is prevented from moving downwardly by the latch 92.

When the device is to be deactivated, the solenoids 84 and 90 are activated. The solenoid 90 withdraws the latch 92 and the solenoid 84 pulls the plate 78 down against the action of the spring 88. When the solenoid 90 de- energizes, the latch 92 is pushed back by the spring 86 into the hole 100 thereby holding the plate 78 in its lowered position.

To activate the device, the solenoid 90 is energized whilst the solenoid 84 remains de-energized. The spring 88 thus pushes the plate 78 upwards to the illustrated position. De-energization of the solenoid 90 allows the spring 96 to push the latch 92 below the lower edge of the wall 76 thereby preventing the plate from being pushed down.

A switch (not shown) of any of the forms described above can be provided on the wall 76 and a sounder (not shown) can be provided in the housing 72. The circuitry of the switch and sounder can be as described above.