Lock

#This invention relates to a lock for a movable wing, and particularly to a lock intended to be rim fitted to a domestic entrance door.

#According to the invention a lock for a wing movable between respective open and closed positions relative to a frame comprises a casing, a bolt operable to extend from the casing or to retract into said casing to a first, normally retracted position, and bolt retention means manually operable at one side of the wing, in use, the bolt retention means being inoperable when said bolt is in its said first, normally retracted position, the bolt being movable in a direction into the casing from its first, normally retracted position, to a second retracted position in which said bolt retention means is operable to a position to retain the bolt retracted.

#Preferably said bolt retention means retain the bolt in its first retracted position. More preferably said bolt is releasable from its retention in its first retracted position only by movement of the bolt to its said second retracted position. Desirably said release of the bolt from the bolt retention means is automatic when said retained bolt reaches its second retracted position. Conveniently in said second retracted position, part of said bolt engages a rear wall of the casing.

#The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

#FIG. 1 is a schematic internal side view of a casing of a lock of the invention, with a bolt thereof in its normally retracted state and a handle in its rest position,

#FIGS. 2 and 3 are respective views similar to FIG. 1, showing the bolt partly and fully extended from the lock casing,

#Shown in the Figures is a lock of the invention, which in the illustrated embodiment is rim mounted, i.e. as shown in FIG. 23, is intended to be mounted at one side and partly at one front edge surface of a wing such as a conventionally hinged door 10 which has an associated frame and staple (not shown) so that the door can be moved between an open position and a closed position in which it is locked by a bolt of the lock, such bolt being described hereinafter.

#The lock has a metal casing made up of a main body part 11, in the general form of a square box structure having one side open, and a closure part 12 in the form of a flat square metal plate. The plate has respective holes at or adjacent each of its four corners for fixing screws passing into respective threaded bores in bosses formed with the body part 11, to secure part 12 in place inwards of the plane of the outer free edge surface of the part 11, and to complete the lock casing with the assembled components therein concealed from view.

#As mentioned, the main body part 11 is in the form of a square box-structure and FIG. 23 shows a side wall 13 integrally formed with an end wall 14 and a front wall 15 which is extended from the side wall 13 further than the end wall 14 to form a forend of the lock, with the extension part of the wall 15 being secured to a front edge surface of the door 10 as shown in FIG. 23, with the free edge surface of the end wall 14 engaging against the inner side of the door, in use, again as shown in FIG. 23. The main body part 11 is completed by a bottom wall 16, and a parallel top wall 17 shown in FIGS. 17 and 18.