US3029096A

US3029096A - Deadlocking latch unit for door locks

Info

Publication number: US3029096A
Application number: US757245A
Authority: US
Inventors: Nicholas A Welch
Original assignee: American Hardware Corp
Current assignee: Emhart Industries Inc
Priority date: 1958-08-26
Filing date: 1958-08-26
Publication date: 1962-04-10
Anticipated expiration: 1979-04-10

Description

April 10, 1962 N. A. WELCH DEADLOCKING LATCH UNIT FOR DOOR LOCKS Filed Aug. 26, 1958 2 Sheets-Sheet l H TTOPNLL/ April 10, 1962 N. A. WELCH DEADLOCKING LATCH UNIT FOR DooR Locxs 2 Sheets-Sheet 2 Filed Aug. 26, 1958 IN V EN TOR. /V/c//oL/vs /7. Wzl, CH

inired 3,029,096 DEADLOCKING LATCH UNIT FR DOOR LOCKS Nicholas A. Welch, West Hartford, Conn., assigner to The American Hardware Corporation, New Britain,

Conn., a corporation of Connecticut Filed Aug. 26, 1958, Ser. No. 757,245 9 Claims. (Cl. 292-336) This invention relates to a deadlocking latch unit for door locks and more particularly to a latch unit for emergency-exit locks which is adapted to be mounted at the top of a door for cooperation with a keeper in the head-jamb of the door frame.

The primary object of the present invention is to provide a latch unit which is particularly suited for installation in the narrow tubular stiles of metal doors such as, for example, those having a framework of eX- truded aluminum members.

A further object of the invention is to provide a latch unit having a mechanism of compact construction which may readily be mounted in the narrow tubular stile of a door or in a small unobtrusive housing for rim application.

Another object of the present invention is to provide a latch unit having a novel latch bolt operating mechanism which consists of but few parts and is therefore economical to manufacture, yet strong and durable in construction.

A still further object of the invention is to provide such a latch unit which may be used with a variety of conventional latch operating mechanisms.

Further objects and advantages of the invention will be more clearly understood from the following description and the accompanying drawings in which:

lFIG. l is a fragmentary plan view illustrating the latch unit of the present invention mounted in the tubular metal stile of a door.

FIG. 2 is a sectional elevational view illustrating the latch mechanism when the door is closed.

FIG. 3 is a sectional view showing the inner side of the latch unit and further illustrating the construction thereof.

FIG. 4 is a sectional elevational view illustrating the opposite side of the latch unit from that shown in FIG. 2.

FIG. 5 is a sectional plan view of the latch unit taken on line 5-5 of FIG. 2.

FIG. 6 is a View similar to FIG. 2 illustrating the mechanism of the latch unit when the latch bolt is retracted and just before the door is opened.

FIG. 7 is a similar view illustrating the condition of the latch mechanism when the door is opened.

FIG. 8 is a view similar to FIG. 4 further illustrating the operation of the latch unit.

The latch unit illustrated in the drawing is intended to be installed in the tubular metal stile of a door, but it will be readily understood that with slight modification my improved latch unit could be adapted for rimtype application on a door without departing from the spirit of the present invention.

Referring now to the drawings, and particularly to FIGS. l through 5 thereof, the numeral 5 denotes a conventioual door having a framework that is composed of a plurality of tubular members including a vertical outer stile 6 that is open at its upper end. Emergency-exit doors of the type for which my novel latch unit is intended are commonly used in pairs, but in the drawings l have illustrated only one of said doors.

My improved latch unit includes an elongated housing 7 that is open at both ends and is made to lit snugly into the upper end of the stile 6. The housing has an Cil 3,929,095 Patented Apr. l0, 1962r outer wall 8 and spaced parallel side walls 9-9 from the inner edges of which extend opposed laterally directed wings 1li-10 containing threaded holes l1. The housing is secured in the stile 6 with its upper edge substantially llush with the upper edge of the stile by screws 12 which extend through the inner side of lthe stile and are threaded into the holes 11 in the wings itl-All.

Openings are provided adjacent the upper inside corners of the side walls 9 9 of the housing for the ends of a shaft 13 which extends transversely across the housing and pivotally carries a latch bolt 14 and a trip latch 15, both of which are of identical bell-crank conguration. The latch bolt is considerably thicker than the trip latch and includes a head 16 having an outwardly facing, curved, keeper engaging face 16-a and an arm 17 which extends downwardly from the inner end of the head into the housing. The trip latch has a similarly shaped head 18 and depending arm 19, the inner edge of which is provided with a slot 2t) (see FIGS. 3 and 4) adapted to receive a hairpin spring 21 that is coiled around the shaft 13 and has one arm bearing against the trip latch and its other arm bearing against the adjacent wing 10 whereby said trip latch is normally biased toward projected position.

The latch bolt 14 is controlled by an. actuating plate 22 that is mounted for vertical sliding movement in the housing between the depending

arms

17 and 19 of the latch bolt and the trip latch, respectively, as best shown in PlG. 3. In the form of the invention illustrated, the actuating plate 22 consists of two L-shaped plate members 22-a and 22b which are secured together in opposed relation by rivets 23 thus providing

opposed ilanges

24 and 25 on said actuating plate which slidably guide the lower end thereof inthe housing. lt is evident, however, that the actuating plate could be made of one-piece construction if desired.

on its side adjacent the arm i7 of the latch boit, the

actuating plate 22 is provided with an arcuate cam slot 26 which is closed at both ends and slidably receives a cam follower stud 27 projecting laterally from the end of said arm 17. On its opposite side, the actuating plate is provided with an arcuate slot 2S that is adapted to receive a detent stud 29 projecting laterally from the end of the arm 19 of the trip latch l5 for a purpose to be hereinafter described. It will be noted that a portion of plate member 22-b above the slot 2.8 is cut away to provide, in effect, a vertical channel 22-c in the actuating plate which communicates with the slot 2S and which normally accommodates the stud 29 to permit unhindered vertical movement of the actuating plate.

At its lower end, the actuating plate is provided with suitable means for attaching it to the upper end of a latch operating rod 36 forming part of a conventional emergency-exit lock mechanism (not shown). ln the present case, the rod 30 is disposed vertically in the interior of the stile 6 and is connected at its lower end to the latch operating mechanism of said emergency-exit lock. Said mechanism may include a panic-bar having a connection with the operating rod and preferably operates in such a manner that when the panic-bar is depressed, or moved toward the door, the operating rod is raised to actuate the latch unit, and when the panic-bar is released, the operating rod is gravitationally biased downwardly toits normal position.

In FIG. 2 of the drawings, I have illustrated the condition of the latch mechanism when the door 5 is closed. The actuating plate 22 and the operating rod 30 are gravitationally biased downwardly by their own weight and thus normally occupy their lowermost position illustrated in FIG. 2. When in this position, the latch bolt 14 is projected by the cam slot 26 and the head 16 of said latch bolt extends above the top of the door into the opening in a conventional keeper 31 that is mortised into the head-jamb 32 of the door frame. The cam slot 26 is preferably formed with a vertically disposed portion 26-a at its upper end which receives the stud 2'7 when the latch bolt is projected. The latch bolt is thus deadlocked and cannot be forced into retracted position from the outside with a tool inserted between the top of the door and the head-jamb 32. When the door is closed, the head 18 of the trip latch is disposed in engagement with the bottom face of the keeper 31 and said trip latch is thus maintained in retracted position against the bias of the spring 21 as illustrated in FIGS. 2 through 4.

When the latch operating mechanism of the emergency-exit lock is actuated to open the door, the rod 30 and the actuating plate 22 are raised. As the actuating plate moves upwardly, the latch bolt is urged about the shaft 13 toward retracted position through the action of the cam slot 26 on the stud 27. When said stud engages the lower end of the cam slot, further upward movement of the actuating plate is prevented, but by this time the latch bolt has been fully retracted and is free of the keeper as illustrated in FIG. 6. As the door is opened, the spring 21 urges the trip latch 15 in a clockwise direction about the shaft 13 and into projected position as illustrated in FIG. 7. As the trip latch moves into projected position, the detent stud 29 on the end of its depending arm 19 moves into the slot 28 in the actuating plate 22 so that when the panic-bar, or other latch operating mechanism, is released and returned to normal position by the springy means usually provided therein, the actuating plate and the operating rod will be supported in raised position by the trip latch, and the latch bolt will thus be held in retracted position.

When the door is closed, either by the person passing therethrough or by a conventional door closer, the trip latch will be urged into retracted position upon engagement of its projecting head 18 with the keeper 31 and the stud 29 on the arm 19 of the trip latch will move out of the slot 28 to release the actuating plate and the operating rod. Said actuating plate and operating rod are then momentarily supported in raised position by the latch bolt until the door closes fully and the head 16 of the latch bolt moves into register with the opening in the keeper, whereupon, the actuating plate and the operating rod will drop and the latch bolt will be cammed into projected position.

When the latch unit is installed on a door which has been properly hung, the space between the top of the door and the head-jamb of the door frame is such that the latch bolt must be fully retracted before the door can be opened, and the detent stud 29 on the trip latch will therefore normally enter the slot 28 in the actuating plate since said plate must be fully raised to fully retract the latch bolt. However, if the door is improperly hung, or has sagged, and the space at the top of the door is abnormally large, as illustrated in FIG. 8, the latch bolt will move out of engagement with the keeper before it is fully retracted and, therefore, before the actuating plate has reached its fully raised position. In order to permit engagement of the detent stud 29 on the latch with the actuating plate under such conditions, I have provided a notch 33 in the upper edge of the slot 28 which extends inwardly from the inner edge 34 of the plate ZZ-b and is adapted to receive the detent stud 29. It will be seen, in FIG. 8, that when the latch bolt moves out of engagement with the keeper 31 before the actuating plate is fully raised, the detent stud 29 will move into the notch 33 when the door is opened and thereby support the actuating plate and the operating rod in their partially raised position until the door is closed.

l claim:

1. In a latch unit adapted to be mounted adjacent the upper edge of a door for actuation by a vertically reciprocable latch operating member of an emergency-exit lock mechanism; a housing having an open upper end, a

latch bolt pivotally mounted in said housing for movement about a pivot point through said open end between projected and retracted positions, an actuating member mounted in said housing for vertical reciprocable movement and connected directly to said latch bolt, cam means for moving said latch bolt to retracted position when said actuating member is moved upwardly in said housing and to projected position when said actuating member moves downwardly therein, said means including an inclined cam slot on said actuating member, the inclination of said slot being such that an upwardly directed projection thereof will pass in front of and away from said pivot point, and a cam follower on said latch bolt engaging said cam slot, and trip latch means mounted in said housing movable into engagement with said actuating member when the latch bolt is retracted and the door is opened to retain said actuating member in latch bolt retracting position.

2. A latch unit as set forth in claim 1, wherein said cam slot is cut into the surface of said actuating member and said cam follower projects into said slot.

3. A latch unit as set forth in claim l, wherein said latch bolt is of bell-crank form having a head portion swingable through said open end, said bolt further having an arm portion depending from said head portion into said housing, said cam follower being positioned on said arm.

4. A latch unit as set forth in claim l, wherein said trip latch means includes a trip latch, means urging said trip latch toward retaining position when said door is open, a detent on said trip latch, and means providing an abutment on said actuating member with which said detent is engageable when said actuating member is moved to latch bolt retracting position and said trip latch is in retaining position for retainingA said actuating member in latch bolt retracting position.

5. In a latch unit adapted to be mounted adjacent the upper edge of a door for actuation by a vertically reciprocable latch operating member of an emergency-exit lock mechanism; a housing having an open upper end, a latch bolt mounted in said housing for movement through said open end between projected and retracted positions, an actuating member mounted in said housing for vertical reciprocable movement and adapted to be connected to said latch operating member, cam means for moving said latch bolt to retracted position when said actuating member is moved upwardly in said housing and to projected position when said actuating member moves downwardly therein, said means including cam surfaces on said actuating member and a cam follower on said latch bolt engaging said cam surfaces, and trip latch means mounted in said housing movable into engagement with said actuating member when the latch bolt is retracted and the door is opened to retain said actuating member in latch bolt retracting position, said actuating member being provided with a detent slot and said trip latch means including a detent which moves into said detent slot when the actuating member is in latch bolt retracting position for holding said actuating member in said latch bolt retracting position.

6. In a latch unit adapted to be mounted adjacent the upper edge of a door for actuation by a vertically reciprocable latch operating member of an emergency-exit lock mechanism; a housing having an open upper end, a latch bolt mounted in said housing for movement through said open end between projected and retracted positions, an actuating member mounted in said housing for vertical reciprocable movement and adapted to be connected to said latch operating member, cam means for moving said latch bolt to retracted position when said actuating member is moved upwardly in said housing and to projected position when said actuating member moves downwardly therein, said means including cam surfaces on said actuating member and a cam follower on said latch bolt engaging said cam surfaces, and trip latch means mounted` in said housing movable into engagement with said actuating member when the latch bolt is retracted and the door is opened to retain said actuating member in latch bolt retracting position, said trip latch means including a trip latch pivotally mounted in said housing and hav ing a head portion swingable through said open end thereof between projected and retracted positions, said trip latch being normally retained in retracted position when the door is closed through engagement of said head portion with a portion of the door frame, a spring urging said trip latch toward projected position, a detent on said trip latch, and means providing an abutment on said actuating member with which said detent is engageable when said actuating member is in latch Ibolt retract ing position and said trip latch is in projected position for retaining said actuating member in latch bolt retracting position.

7. In a latch unit adapted to be mounted adjacent the upper edge of a door for actuation by a vertically reciprocable latch operating member of an emergency-exit lock mechanism; a housing having an open upper end, a latch bolt and a trip latch of bell-crank form pivotally mounted in said housing each having a head portion swingable through said open end between projected and retracted positions and an arm depending from said head portion into said housing, an actuating plate mounted for vertical reciprocable movement in said housing between the depending arms of said latch bolt and said trip latch and adapted to be connected to said latch operating member, said actuating plate having a cam slot in the side thereof adjacent said latch bolt, a cam follower extending from the arm of said latch bolt into said cam slot, said cam slot being arranged to cause movement of said latch bolt to retracted position when said actuating plate is moved upwardly in said housing and to projected position when said actuating plate moves downwardly therein, said trip latch being normally retained in retracted position when the door is closed through engagement of its said head portion with a portion of the door fraaie, a spring urging said trip latch toward projected position, a detent on the arm of said trip latch, said actuating plate having a separate slot in the side thereof adjacent rthe trip latch adapted to receive said detent when said actuating plate is in latch bolt retracting position, said detent being movable into said separate slot when said trip latch is urged into projected position by said spring as the door is opened to thereby retain said actuating plate in latch bolt retracting position.

8. The subject matter set forth in claim. 7 wherein said separate slot is provided with a notch in its upper edge opening to the end of said slot and adapted to receive said detent when the door is opened with the actuating plate in an intermediate position.

9. In a latch unit adapted to be mounted adjacent the upper edge of a door for actuation by a vertically reciprocable latch operating mem-ber of an emergency-exit lock mechanism; a housing having an open upper end, a latch bolt mounted in said housing for movement through said open end between projected and retracted positions, an actuating member mounted in said housing for vertical reciprocable movement and adapted to be connected to said latch operating member, cam means for moving said latch ybolt to retracted position when said actuating member is moved upwardly in said housing and to projected position when said actuating member moves downwardly therein, said means including cam surfaces on said actuating member and a cam follower on said latch bolt engaging said cam surfaces, and trip latch means mounted in said housing movable into engagement with said actuating member when the latch bolt is retracted and the dooris opened to retain said actuating member in latch bolt re- `tracting position, said cam surfaces being provided by a cam slot in said actuating member, said slot being obliquely inclined and being provided with a vertically disposed portion at its upper end to receive said cam follower when the latch bolt is projected to thereby deadlock said latch bolt.

References Cited in the le of this patent UNITED STATES PATENTS 1,488,350 Kikta Mar. 25, 1924 1,518,187 Dyer Dec. 9, 1924 2,762,642 Jewett Sept. 11, 1956 2,781,218 Jewett Feb. 12, 1957