Door Locking Mechanism

This invention is applicable to locks which have only a dead bolt as well as to locks having a dead bolt and a spring latch, or a spring latch only. In all instances a single strike case is needed. Both dead bolt and spring latch are released by the action of a single keeper.

The keeper returns automatically to locked condition when the dead bolt reenters the strike case. The door may be closed with dead bolt extended.

The keeper is held open after the door is opened if the dead bolt was in extended position at the time the door was opened. If only the spring latch is extended but not the dead bolt, the keeper returns to locked condition once the latch has cleared the strike.

In its simplest embodiment the strike case is merely adapted to receive a dead bolt. A pivoted keeper is provided for selectively opening and closing said strike case. The keeper is under the action of bistable spring means acting on the keeper to maintain the keeper either in the fully open position, or in the fully closed position thereof. Said bistable spring means maintains said keeper in said fully open position, if said dead bolt is extended when the door is opened. The lock further includes a latch bolt for maintaining said keeper in said fully closed position thereof when said bistable spring means has moved said keeper to closed position.

FIG. 1 is a top plan view of the complete lock in the closed and latched position of its keeper;

Fig. 2 is an elevational view of the lock of FIG. 1 with the dead bolt and the spring latch removed in order to expose to full view the striker case and the parts of the keeper inside of the striker case;

FIG. 3 is a side elevation of the keeper including the solenoid thereof;

FIG. 4 is an isometric view of the entire assembly;

FIG. 5 shows the keeper and the strike case in top-plan view with the keeper in open position thereof;

FIG. 6 shows the keeper and the strike case in top-plan view with the keeper in the closed position thereof; and

FIG. 7 shows some details of the keeper.

Referring now to the drawings, numeral 1 has been applied to indicate a door and numeral 2 has been applied to indicate a strike case. A dead bolt 3 is movable into and out of strike case 2. The dead bolt 3 has an extended position and a retracted position, and FIG. 1 of the drawing shows the dead bolt in its first mentioned position. Reference numeral 4 has been applied to indicate a spring latch bolt. The presence of such a bolt is optional rather than mandatory. Reference numeral 5 has been applied to indicate the housing of a keeper pivotable about a pair of pins 6. In the position shown in FIG. 1 the keeper is in closed position and a latch bolt thereof engages a recess in the strike case. A return spring 7 tends to maintain the keeper 5 in the position shown. When the solenoid inside keeper 5 is energized, the latch bolt leaves the aforementioned recess in strike case 2 and then keeper 5 can be pivoted in counter-clockwise direction as indicated by the arrow R. Reference numeral 8 has been applied to indicate a substantially U-shaped spring that forms an abutment cooperating with dead bolt 3.

Referring now to FIG. 2, this figure shows the strike case 2 having two apertures 2a for affixing it to the door jam. Inside the strike case 2 the aforementioned return spring 7 and abutment 8 are visible. The keeper 5 houses the solenoid 5a (see FIG. 3), its plunger 5b, and the bias spring 9 supports latch bolt 5c. With the keeper 5 in the closed position, latch bolt 5c engages projections 2b in strike case 2 as a result of the extension of bias spring 9.

FIG. 3 shows the two pins 6 pivotally supporting keeper 5. It will be observed that the two wires 8a, 8b used for energizing solenoid 5a are threaded through one of pins 6 so that the wires do not need to be bent at each pivotal motion of keeper 5 and of its solenoid 5a.

FIG. 4 shows the aforementioned parts but keeper 5 is open rather than closed.

As shown in FIG. 4, the keeper 5 has been pivoted in the sense of arrow R and is, therefore, in its open position wherein it is held by overcenter spring 7. The dead bolt 3 is in its extended position. When moved in the sense of arrow S it will hit upon abutment 8 and reclose the strike 2, which will then pivot in the direction indicated by arrow R" to the closed position shown in FIGS. 1 and 2. Keeper 5 is under the action of over center spring 7. In the position shown in FIG. 4 keeper 5 is in its stable open position. As it is moved in the direction of arrow R" it reaches an unstable position. Further movement in the closing direction of keeper 5 results in a reversal of the bias of spring 7 and hence in movement of the spring-biased keeper 5 to its closed position. FIG. 4 shows also the spring latch 4.

FIGS. 5 and 6 show a portion of the above described mechanism but on a larger scale. FIG. 5 shows the keeper in the open position and FIG. 6 shows the keeper in the closed position. FIGS. 5 and 6 are self-explanatory since the same reference characters have been applied in these figures as in the figures previously described.

FIG. 7 shows a modification wherein the keeper 5 and its strike have overlapping joints indicated at 5d and latch bolt 5c is covered with a latch guard 2d which precludes insertion of a tool for driving latch 5c in upward direction, i.e. in the direction of arrow T.