Latch mechanism with jamb mounted latch bolt

DETAILED DESCRIPTION The present invention overcomes these inadequacies of the conventional type of door lock by providing a novel latch mechanism in which the latch bolt is moveably carried by the door jamb rather than the door itself and a co-acting keeper or strike unit is carried by the door, in conjunction with a retracting part which is also carried by the door and is adapted to be manually actuated in a manner retracting and thereby releasing the latch bolt to permit opening movement of the door.
The retracting part is actuable by a knob or other operating handle carried by the door, with movement of that knob or other handle preferably being controlled by a key actuated lock unit.
The retracting part may be a sliding element which in the closed condition of the door is located directly opposite the latch bolt, and is slidably moveable toward the latch bolt to push it to a retracted position and out of holding engagement with the keeper.
Such movement of both the latch bolt and retracting part may be yieldingly resisted, desirably by two springs associated with these two parts respectively.
The latch bolt may have an inclined camming surface which is engaged and deflected by the keeper during closing movement of the door.
This camming surface, however, is desirably so located as to not be easily accessible to a person attempting to open the door without authorization.
For this purpose, the cam surface should preferably be located at a side of the latch bolt facing generally toward the inside of the doorway, that is, facing in a direction away from the side at which the person attempting unauthorized entry will be located.
As a result, the bolt cannot be retracted merely by insertion of a knife blade, card, or the like into the space between the door and door jamb.
In addition, the jamb carried mechanism preferably also includes a blocking projection extending outwardly at a location beyond the latch bolt and in the direction of closing movement of the door, to block movement past that location of any special hook shaped tool or element by which an intruder may attempt to reach about the latch bolt to its back side to engage and exert retracting force against its camming face