Our UK patent application number 0200677.3 provides a locking mechanism for use with at least one door and/or window of a structure, the mechanism comprising at least one operating handle and at least one electrical operating device.

According to one embodiment of the locking mechanism described in the above mentioned pending patent application, a manual override arrangement is provided, operable from inside a house, for example in the form of a manually rotatable knob.

We have now developed a further embodiment of the locking mechanism which comprises added security under certain conditions, for example when a householder is away on holiday.

The present invention provides a locking mechanism for use with at least one access door of a building, the mechanism comprising at least one operating handle and at least one electrical operating device, the locking mechanism having a first internal device manually operable to activate electrical means of the locking device, and a second internal device manually operable to override the electrical means of the locking device to open the door, the locking device including at least one security locking mechanism operable by the first internal device, release of the security locking mechanism not being possible by operation of the second internal device.

The first internal device may comprise an operating handle, for example in the form of a lever.

Pivoting the lever upwardly once may operate the electrical means of the locking mechanism.

Pivoting the lever upwardly a second time, within a predetermined time e. g. ten seconds, may operate the security locking device.

The second internal device may comprise a manually rotatable knob.

The security locking mechanism may comprise at least one, and preferably two, dead bolts.

If a householder is going to be away for a significant period of time, for example while on holiday, the lever handle can be pivoted upwardly twice to operate the main electrical locking means and also operate at least one dead bolt. This means that if an intruder breaks in through a window, they cannot then open the access door from the inside using the manual override device.

This in turn means that if the intruder tries to steal anything, the stolen goods must be taken out through a window, which makes it more likely that the theft will be noticed than if the intruder was able to open the door and take goods out through the door.

The security locking mechanism may be such that it can only be released by operation of a remote control device.

The invention includes an access door when fitted with a locking mechanism as defined above.

By way of example, a specific embodiment of the present invention will now be described, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of the access door of a building, fitted with an embodiment of locking device according to the present invention;

Figure 2 is a more detailed view of the internal part of the locking mechanism and that part of the locking mechanism which lies in the side of the building ; and Figure 3 is a perspective view of one dead bolt for use with the locking mechanism.

The access door shown in Figure 1 comprises a panel 10 used to frame 11.

The door has an inner handle 12 attached to the locking mechanism 16 and there is also a similar external handle although this cannot be seen in the figure.

The door has a conventional spring catch 15, two conventional security hooks 17 and a dead bolt 18. The locking mechanism is associated with an operating fob 14 having a push button 13.

In a conventional, unlocked condition, the internal handle 12, and the external handle, can be used to open and close the door, the spring catch 15 keeping the door closed when the panel 10 is flush within the frame 11.

If it is desired to engage the security hooks 13, this can be done in a conventional manner, using an internal espagnolette (not shown) by pivoting the handle 12 or the external handle upwardly.

An additional dead bolt 80 shown in Figure 3 is fitted into the frame 11 of the door assembly. A second identical dead bolt is fitted at a spaced apart location. Each dead bolt 80 is arranged so that it can be actuated electrically to cause the bolt 81 to project into a socket in the edge of the door, preventing the door from being opened. For example a small electrical motor within the dead bolt 80 may be arranged to rotate a threaded drive member 82.

When the door handle 12 is pivoted upwardly a first time, electrical means of the locking mechanism is actuated and the door is locked from the outside.

However the door can still be opened manually from inside by rotating the knob 19 shown in Figure 2. This electrical locking operation may take place as described in our UK patent application number 0200677.3 and the corresponding international application PCT/GB2003/000111.

If the handle 12 is pivoted upwardly for a second time, within a predetermined time from its first actuation (for example 10 seconds) then this causes the bolts 81 and the dead bolts to project into their locking position.

The dead bolts can only be retracted when the householder returns, by operation of the key fob 14.

The affect of the invention is that if a householder is going to be away for a significant period of time, for example while on holiday, the lever handle 12 can be pivoted upwardly twice to operate not only the main electrical locking means but also the dead bolts. This means that if an intruder breaks in through a window, they cannot then open the access door from the inside using the manual override device 19. This in turn means that if the intruder tries to steal anything, the stolen goods must be taken out through a window, which it makes it more likely that the theft will be noticed than if the intruder was able to open the door and take goods out through the door.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or

process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s).

The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.