US2719048A - Door latch assembly - Google Patents

Description

Sept. 27, 1955 T. A. HAYES 2,719,048

DOOR LATCH ASSEMBLY Filed April 24, 1952 2 Sheets-Sheet l N V EN TOR.

7740/1199 17 HH/es Sept. 27, 1955 T. A. HAYES DOOR. LATCH ASSEMBLY 2 Sheets-Sheet 2 Filed April 24, 1952 INVENTOR. THO/1,75 /7. Hares United States Patent Ofiice 2,719,048 Patented Sept. 27, 1955 DOOR LATCH ASSEMBLY Thomas A. Hayes, West Cheshire, Conn., assignor to The American Hardware Corporation, New Britain, Conn., a corporation of Connecticut Application April 24, 1952, Serial No. 284,143

2 Claims. (Cl. 292-92) This invention relates to a, door latch assembly and more particularly to a novel latch and the operating mechanism therefor for use on fire exit doors and the like.

Fire exit doors are commonly used in public buildings such as schools, theaters and the like, and are customarily provided with door latch mechanisms having operating means that are actuated by pressure thereagainst so that in the event of panic in such a public building, as a, result of a fire or other disaster, the emergency exit door can be opened outwardly by merely pressing against the operating or actuating means.

The latch mechanisms commonly used on such doors have been subject to certain disadvantages due, in part, to their intricate and complex construction, and the services of a highly skilled mechanic have been necessary to assure proper installation of the latch and the latch operating mechanism as some parts therefor must be cut and threaded before assembly thereby greatly increasing the possibilities of human error and consequent malfunction of the door latch. Furthermore, fire exit door latches of the conventional type heretofore produced will not latch properly if the door should warp or sag and, after considerable wear has occurred due to constant use, an excessive amount of play is present between the latch and its keeper thereby permitting the door to rattle.

It is, therefore, an important object of the present invention to provide a door latch assembly for fire exit doors which can be easily and properly installed by an unskilled person.

Another object of the invention is to provide a simplified door latch assembly of the described type which is foolproof in operation, sturdy and durable and which practically eliminates the possibilities of malfunction even if improperly installed.

A still further object of the invention is to provide a door latch assemlby, having the foregoing characteristics, which can be economically manufactured and furnished to the consumer in subassemblies which permit adaptation of the door latch to emergency exit doors of many different heights.

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

Fig. 1 is a foreshortened view in vertical section through the door frame for a fire exit door showing the door in closed and latched position and illustrating the latch and the latch operating mechanism with some of the parts therefor in central vertical section to more clearly illustrate the construction of said mechanism.

Fig. 2 is a similar elevational view of said door frame and door illustrating the door latch and the latch operating mechanism.

Fig. 3 is a side view of the door latch, partly in section, illustrating the latch elements in latched, or locked, position.

Fig. 4 is a front view, partly in section on line 4-4 of Fig. 3, further illustrating the construction of the said door latch.

Fig. 5 is a sectional View of the door latch showing the position of the latch elements when the. door is open and is moving towards closed position.

Fig. 6 is a front view thereof partly in vertical section.

Fig. 7 is an exploded perspective view illustrating some of the parts of the door latch and the operating mechanism therefor and the-relative positions which they occupy in the assembly.

Fig. 8 is a view similar to Fig. 1, but showing the door latch in central vertical section and illustrating the position of the latch elements after the operating mechanism has been depressed just prior to the opening of the door.

Fig. 9 shows a cross section taken on. line 9-9 of Fig. 8.

Referring to the drawings, it will be seen that the numeral 5 denotes a hinged door of conventional form arranged to selectively close an emergency or. fire exit defined by door jambs 6, a lintel 7, and a floor 8'. A conventional door stop 9 is secured to the jambs and lintel to engage the marginal portion of the inner face of door when the same is in closed position, and conventional hinges (not shown) are mounted along the right hand edge of the door, as viewed in Fig. 2, and the door jamb to permit outward swinging movement of the door to open position.

The door latch assembly embodying the present invention is arranged on the inner face of the door 5 adjacent and along the left hand or free edge 10 thereof.

The details of the door latch included in said assembly will be described immediately hereinafter, but it is desired to point out here that said latch is arranged to be operated by conventional actuating means including a horizontally disposed bar 11 supported at its left and right hand ends by the levers 12 and 13', respectively. The actuating bar 11 is commonly referred to as a panic bar which, when pressed, will pivot the levers 12 and 13 downwardly. The levers 12 and 13 are pivotally mounted within similar supporting cases 14, and 15, respectively, which are secured to the inner face of the door 5 by screws 16. As will be shown later, the lever 12 is the operating lever for the door latch and the lever 13 functions only as a pivoted support for the opposite end of the actuating bar 11 which extends across the face ofv the door 5.

The latch is arranged adjacent the top of the door, and with particular reference to Figs. 3 to 7, it will be seen that the latch includes a latch case 20 having laterally extending flanges 2121 which engage the inner face of the door 5 and are secured thereto by screws 22. A latch supporting bracket 23 is disposed within the case 20, and said bracket has laterally extending notched arms 2424 which are received within suitable indentations 20-a-20-a on the back side of the flanges 2121 and are secured by the screws 22 against the inner face of the door 5 as shown by Figs. 3 and 4; the notches in the ends of said arms 24 providing clearance for said screws.

The bracket 23 has inwardly extending ears 25-25 which support a latch bolt 26 and a latch operating rod 27. The bolt 26 is of arcuate configuration having an axial opening 28 therethrough arranged to receive a pivot pin 29 which is journalled at its, ends in oppositely disposed apertures 3030 in the ears 25-25 of the supporting bracket 23. When the latch is assembled, axial movement of the pin 29 is prevented by the closely fitting side Walls of latch case 20 as illustrated in Figs. 4 and 7. The bolt 26 has spaced depending legs 3131 arranged to straddle the flattened upper end 32 of the operating rod 27. The extremity of each leg 31 has an inclined cam surface 33 arranged to be engaged by a pin 34 which extends through an opening 35 in the end 32- of said rod and projects into oppositely disposed vertical slots 36-36 in the bracket ears 2525. The side walls of the latch case 20 also prevent axial movement of the pin 34.

The bolt 26 has a cavity 37 therein that is accessible through a wide opening 38 in the upper portion of the front wall of the case 20. The bolt is so disposed on the support bracket that the cavity 37 will receive a combination strike and keeper 40 which is mortised into the top door stop and secured thereto by screws 41. The strike depends from the door stop in registry with the opening 38 in the latch case 20 so as to engage within the cavity 37 in the latch bolt 26 when the door is closed against the stop 9.

The operation of the aforedescribed latch elements can be readily understood if the door 5 is first considered to be in the open position as shown in Fig. 5. In such position, the latch operating rod 27 is in its uppermost position, having been raised by means which will be described later, and the pin 34 carried by the said rod is positioned adjacent the upper ends of the slots 36-36. The rod and pin are retained in raised position by the latch bolt 26, the legs 31-31 of which are each provided with a hooked inner peripheral surface 42 which engage the underside of the pin 34 when the same is raised to the position shown in Fig. 5. Engagement between said legs and pin is effected in the described manner because the latch bolt 26 is eccentrically balanced to rotate in the clockwise direction as viewed in Fig. 5. The extent of bolt rotation is limited by engagement between a shoulder 43 on the periphery of the bolt and the edge 44 on the latch case 20 which defines the lower margin of the opening 38.

In the aforedescribed rotated position of the latch bolt, the bolt cavity 37 is disposed to readily receive the strikekeeper 40 upon moving the door toward closed position. When the door is moved toward closed position, a projecting nose 45 on the strike-keeper 40 strikes the surface 46 within the bolt cavity 37 and rotates the bolt in a counterclockwise direction. Counterclockwise movement of the bolt effects disengagement between the hooked portions of the bolt legs 3131 and the pin 34 thereby permitting the pin to drop downwardly in the slots 3636 due to the weight of the rod 27 and the remainder of the latch mechanism. As the pin 34 falls within the said slots it engages the cam surfaces 3333 on the ends of the bolt legs as shown in Fig. 3. It will be readily understood from this figure, that the falling pin and rod will cam the bolt 26 toward further counterclockwise movement and it will also be understood that, due to the disposition of the cam surfaces 33-33, slight downwardly directed forces on the pin will create much greater rotative forces on the bolt 26. The said forces on the bolt will urge the surface 50 in the bolt cavity against the keeper face 51 of the strike-keeper 40. Said forces brought about by the rod and pin are suflicient to effect closing of the door 5 by action of the bolt after the same has been initially rotated to permit the rod and pin to drop. The maintenance of said forces on the bolt also prevents the door from rattling. The pin 34, when positioned as shown in Fig. 3, functions as a stop member preventing clockwise movement of the bolt thus preventing unlatching of the door until the rod 27 has been elevated.

The rod 27 projects through an opening 52 in the bottom of the latch case 20 and extends downwardly along the free edge of the door as shown in Figs. 1, 2 and 8 and into an opening 53 in the top of the support case 14. Within the support case 14, the rod 27 is telescopically received by a tube 54. The tube 54 projects through an opening 55 in the bottom of the support case 14 and extends downwardly along the free edge of the door being supported for longitudinal movement therealong by a bracket 56. The tube terminates just short of the bottom of the door.

The rod 27 and the tube 54 are secured together by a transverse pin 60 so that longitudinal movement of one will cause corresponding movement of the other. The upper end of the tube 54 is provided with a flange 61, the underside of which is engaged by a pair of legs 62-62 which straddle the tube and form a part of the operating lever 12. The operating lever is pivotally mounted to the support case by a pin 63 so that said lever functions as a bell crank. When the operating lever 12 is pivoted about the pin 63, as by bringing pressure against the actuating bar 11, the legs 62-62 elevate the tube 54 and, accordingly, the rod 27 is also elevated.

From the foregoing description of elements taken in connection Figs. 1, 2 and 8, it will be readily understood that when the actuating bar 11 is pressed causing the rod 27 to be elevated, the latch mechanism at the top of the door 5 will be disengaged. Fig. 8 clearly shows the disposition of the latch elements immediately after the actuating bar has been pressed. In said position, the pin 34 has been raised upwardly in the slots 3636 into registry with a notch 64 between the legs 3131 and the bottom of the bolt 26 to permit clockwise rotation of the bolt 26. Said bolt, as previously mentioned, is eccentrically balanced so that clockwise movement thereof will be gravity biased. In any event, the bolt will be rotated clockwise by the surface 51 of the strike-keeper when the door is pushed outwardly. When rotated clockwise to the position shown in Fig. 5, the legs 31-31 of the bolt will, as previously described, retain the pin 34 and operating rod 27 in elevated position. Further pressure on the actuating bar 11 will thus have no effect upon the rod and tube and once the door has been unlatched, latching cannot be effected until the door and latch mechanism are closed upon the strike-keeper.

The above described unlatching movement of the actuating bar and operating lever also causes unlatching of the latch elements engaging the keeper means in the fioor 8. Said latch elements include a plunger, or bolt, 70 longitudinally movable in the lower end of the tube 54. The plunger 70 extends below the end of the tube so as to be engageable within a keeper 71 imbedded in the floor 8. A spring 72 is located between the top of the plunger and a transverse pin 73 carried by the tube biases the plunger downwardly. A second transverse pin 74 rides in a notch 75 in the side of the plunger to limit the extent of longitudinal movement thereof.

When the tube and rod are elevated, as shown in Fig. 8, the plunger is lifted from the keeper to permit the door to swing outwardly. When the door is closed, the rod and tube are dropped by the latch bolt 26, as previously described, and the plunger 70 enters the keeper 71. The keeper has a cam edge 76 facing the door to cam the plunger upwardly against the spring 72 as the door is closed to assure proper latching. The cam edge enlarges the fitting or assembly tolerances for the tube so that exact fitting is unnecessary to proper operation.

The manner in which the latch mechanism is fitted to the door will probably be apparent from the foregoing description, but the following steps are suggested to facilitate the assembly.

First, the supporting cases 14 and 15, which are packaged or furnished complete with the actuating bar 11, levers 12 and 13, the tube 54 and lower latch elements, are secured 011 the door 5 with the tube 54 positioned to effect latching at the bottom of the door. Then, the latch case 20, furnished complete with rod 27 extending therefrom, is held against the door in approximately true position to locate the strike-keeper 40 on the door stop 9. The strike-keeper is secured in position and then the lower end of the rod 27 is inserted through the opening 53 and into the tube 54 and the latch case 20 finally positioned relative to the strike-keeper 40. After securing the latch case 20, the workman then drills a hole through the telescoped rod and tube and inserts the pin 60 therethrough; peening the ends thereof to prevent inadvertent disassembly of the parts.

Obviously, the foregoing assembly process does not require the services of a highly skilled mechanic. The described structural characteristics of the latch mechanism compensate to a relatively great extent any fitting or assembly errors which might possibly occur so that even unskilled persons can undertake to install the latch mechanism of the present invention with every reasonable assurance that their efforts will be marked by success. Furthermore, one can be assured that the latch mechanism will function properly so long as the door itself remains usable.

I claim:

1. In a door latch having a frame, a latch bolt sup ported thereby, and a strike engageable with said bolt and operable to shift the same toward latched position during closing movement of the door, the improvement wherein said bolt has an arcuate body pivotally connected to said frame for rotation about its axis of generation, a strike receiving cavity in its outer periphery and a hooked leg provided with a tapered end defining a cam surface, a pin supported by said frame for limited movement therein, means for biasing said pin into engagement with said cam surface in a direction perpendicular to the axis of rotation of said bolt when the bolt is pivoted toward latched position to further the latching movement thereof and to retain said bolt in latched position, and means operatively connected to said pin to move said pin out of engagement with said cam surface and thereby permit said bolt to move to open position whereby the hooked portion of said leg engages said pin to retain the same in retracted position.

2. In a door latch having a latch bolt and a strike engageable with said bolt and operable to shift the same toward latched position during closing movement of the door, the improvement comprising a U-shaped bracket, a pin bridging the legs of said bracket and forming an axis of rotation for said bolt, said bolt having an arcuate body, a strike receiving cavity in its outer periphery, a pair of hooked legs projecting outwardly therefrom as an extension of said periphery, and an abutment cam surface at the ends of said legs, there being a pair of opposed slots in the legs of said bracket directed radially of the axis of rotation of the bolt, a pin slidably supported in said slots and movable against said abutment cam surface, and a pin-elevating rod secured to said pin and adapted to move between the legs of said bolt, when said pin and rod are elevated and said bolt is rotated into unlatched position, and a casing for said bracket and bolt.

References Cited in the file of this patent UNITED STATES PATENTS 1,203,115 Hurd Oct. 31, 1916 1,203,116 Hurd Oct. 31, 1916 1,677,271 Carroll July 17, 1928 1,789,775 Russ Jan. 20, 1931 1,844,767 Kelly Feb. 9, 1932

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