Door latch release mechanism

DETAILED DESCRIPTION It is an object of this invention to provide a door latch release mechanism which is capable of overcoming or substantially alleviating some or all of the problems referred to above.
It is a further object of the invention to provide a door latch release mechanism which may be adapted easily to conversion from the "energised locked" configuration to the "energised unlocked" configuration.
Accordingly, this invention comprises a door latch release mechanism having: a housing adapted for mounting in a door jamb; a striker mounted on a shaft in the housing for pivotal movement between a door lock tongue engagement position and a door lock tongue release position; and a stop mounted in the housing and having a portion capable of contacting the striker so as to latch the striker and prevent pivoting thereof from the door lock tongue engagement position, the portion of the stop being generally semi-circular in cross section and the stop being rotatable on its axis so that rotation of the stop to an effective extent releases the striker.
DESCRIPTION OF PREFERRED EMBODIMENTS Preferably, the stop is rotated by electromagnetic means comprising an armature attached to the stop and a core magnetised by a surrounding coil, the armature and the coil each having an inclined surface capable of attraction to each other in response to the application of electrical energy.
In this embodiment, the armature is not affected by gravity and the forces acting on the armature are identical for left hand and right hand doors, which affords the mechanism of the present invention added advantages over the prior art.
In an especially preferred embodiment, the armature is reversibly attached to the stop; reversing of the armature changes the direction of rotation of the stop, thus enabling conversion of the mechanism from a configuration where activation of the armature latches the striker, to a configuration where activation of the armature unlatches the striker.
The conversion may be effected within a few seconds and has significant advantages in enabling the reduction of the amount of stock carried by locksmiths