Background to the Invention A new type of lockable handle assembly is disclosed in our earlier UK Patent Application GB-2,389, 141A, Figures 1 and 2 of which are reproduced in the accompanying drawings.

As shown in Figures 1 and 2 below, the lockable handle assembly of GB- 2, 389, 141A comprises: a handle member 12 to lock a window or door, the handle member 12 being moveable away from a lockable position in order to open the window or door; a handle mounting to which the handle member is pivotally connected ; a locking device/boit 16 having a locked condition where it engages with a keep 10 in the handle mounting for preventing movement of the handle away from the lockable position and an unlocked condition in which the locking device is retracted for allowing movement of the handle away from the lockable position, the locking device 16 being configured to switch between the locked and unlocked conditions in response to an applied magnetic force.

The locking device 16 is resiliently biased by springs 18 to the locking condition so that it remains in this condition when a magnet force is not present. A separately provided key component 22 incorporates a distinctively shaped powerful magnet 24 for switching the locking device when the key 22 is brought into proximity or into contact with the handle 12. Further refinements of the device include an LED and circuit to demonstrate when the switch has been activated.

Whereas this lockable handle assembly is very efficient, the present invention proposes an improvement on the handle assembly in which the objective is to facilitate maintenance of the handle assembly and particularly in case the locking device should fail to operate properly through failure or distortion of the spring or for

any other reason. Such failure is not expected to occur within a very long working life, but nevertheless it is desirable to mitigate against this problem.

Summary of the Invention According to the present invention there is provided a lockable handle assembly for a window or door comprising: a handle member, the handle member having a lockable position to lock a window or door, the handle member being moveable away from the lockable position in order to open the window or door; door; a handle mounting to which the handle member is pivotally connected; a locking device having a locked condition for preventing movement of the handle away from the lockable position and an unlocked condition for allowing movement of the handle away from the lockable position and being resiliently biased to the locked condition, wherein the locking device is exposed to be demountable from the handle assembly when the handle member is turned substantially beyond its normal operational angle of opening movement but is otherwise trapped by the handle mounting against removal.

The normal operational angle of opening movement of the handle assembly is the angle of movement traversed by the handle when moving between closed and open states, whereby a window or door is freed to open. For most applications this is 90 degrees and it is appropriate that the locking device is not exposed over this range.

In the preferred embodiment the locking device is exposed for removal only when the handle member has turned through an angle of greater than 180 degrees from the closed/locked position.

Preferably the locking device is configured to switch between the locked and unlocked conditions in response to an applied magnetic force, as is the case in GB- 2,389, 141A.

In the arrangement of the present invention, should the resiliently biased/spring loaded locking device start to seize up through weakening, distortion or trapping of the spring, then the lockable handle assembly may be firstly demounted from the window installation and the user may then turn the handle through an extreme angle of movement whereby the locking member is no longer trapped between the handle member and the handle mounting to which the handle member is pivotally

connected. The locking member is pushed outwardly by the resilient biasing means and is then simply manually pulled out from the socket within which it is housed in the handle member.

In a particularly preferred embodiment the pivotal connection of the handle member to the handle mounting is offset relative to a longitudinal axis of the handle mounting whereby when the handle member is in a first position substantially perpendicular to the handle mounting, the locking device remains trapped within its socket in the handle member (or within the handle mounting if the locking device is accommodated in the handle mounting) but when the handle member is rotated to the opposing position substantially perpendicular to the longitudinal axis of the handle mounting, the locking device is fully exposed and may be demounted.

In an alternative embodiment of the pivotal connection of the handle member to the handle mounting is not offset but instead the handle mounting is provided with an extension shoulder to one side only so that the same effect of trapping the locking devide at the first position and freeing it at the second is achieved.

Brief Description of the Drawings Figures 1 and 2 are views of the prior art lockable handle assembly of GB- 2,389, 141, with Figure 1 being a side elevation view with part sectional cut away, and Figure 2 being a plan view of the handle assembly.

A preferred embodiment of the present invention will now be more particularly described by way of example, with reference to Figures 3 to 7 of the accompanying drawings, wherein: Figure 3 is a perspective view of the lockable handle assembly of the preferred embodiment from the front/in plan, and corresponds to the Figure 2 view of the prior art; Figure 4 is a perspective view from the underside of the handle assembly of Figure 3 and showing the handle in its closed state, with the handle member base portion aligned with the handle mounting and the locking member engaged with the handle mounting (not visible);

Figure 5 is a perspective view of the handle assembly of Figure 3 from the underside; Figure 6 is a perspective view similar to Figure 5 but of the handle member turned through 180° relative to its position in Figure 5, whereby the locking device is free to pop out from its socket in the handle member; and Figure 7 is a view corresponding to Figure 6 but with the locking device removed from its socket.

Description of the Preferred Embodiment Referring now to Figures 3 to 7, the improved lockable handle assembly is generally the same as that disclosed in GB-2,389, 141A but differs in one highly significant respect in its shape and configuration. Specifically, the spindle 15 which pivotally connects the handle member 12 to the handle mounting 2 lies not along the longitudinal axis L of the handle member 2, unlike the prior art of Figure 2, but rather offset to one side.

As a result of this offset of the spindle 15, when the handle member 12 is turned about the axis of the axle 15, the locking device comprising locking component 16 will be continuously obstructed from removal when the handle is turned through an initial 90° angle to a first perpendicular position (as shown in Figure 5) but when turned through a further 180° to extend in the opposing perpendicular direction laterally from the handle member 2 (as shown in Figures 6 and 7) the locking component 16 is no longer trapped by the body of the mounting 2 and is free to be ejected under the biasing of the springs and by simply pulling the locking component 16 away.

By this simple adaptation of the configuration of the locking handle assembly, it is possible now to carry out maintenance on the locking device/component 16 replacing the springs as necessary or indeed replacing the locking component 16 in its entirety.