Abstract: A latch bolt operating device is adapted for use with a latch bolt unit that is installed in a door panel, and includes exterior and interior operating units. The exterior operating unit includes a key-operated plug-and-cylinder lock assembly, and an exterior housing having an outer annular cover, an inner annular cover and an annular shield. The outer annular cover has a rear end portion formed with a first annular shoulder. The inner annular cover is received in the outer annular cover and has a rear end portion formed with a second annular shoulder. The annular shield extends into the rear end portion of the inner annular cover and has a peripheral portion which engages the second annular shoulder when the latter is bent. The interior operating unit includes a torque bar and an interior housing. The torque bar can be positioned releasably in a first position corresponding to an extended position of a bolt of the latch bolt unit and a second position corresponding to a retracted position of the bolt.

Abstract: A lock assembly includes a linkage mechanism which is operable from the outside of a door via a lever and which is drivingly connected to a latch. An inside operating mechanism which is operable from the inside of the door is connected to the linkage mechanism so that the inside operating mechanism need not be connected to the latch. The lock assembly is suitable for use with a latch having only one cam wheel or two cam wheels.

Abstract: A retaining assembly includes a hollow casing mounted on a door. The casing has a horizontal wall portion formed with a through-hole and an upright rotary shaft which has an end portion that extends out of the casing through the wall portion and which is rotatable relative to the casing. A coupling rod has a first end portion connected pivotally to a door frame and a second end portion connected to the end portion of the shaft so as to, drive rotatably the shaft in a first direction when the door moves relative to the door frame to an open position. A pin has an end portion which is normally biased to extend out of the casing via the through-hole. An elongated positioning plate has a first end portion and a second end portion which is coupled releasably and selectively to the end portion of the shaft such that the first end portion is displaced by a variable initial angle, corresponding to the open position, with respect to the pin when the door is in a closed position.