Abstract:
A high security exit system employs a door latching assembly which cooperates with a frame latching assembly mounted to the door frame. The frame latch is mounted for pivotal movement and has a latching surface movable toward a projected position. When the door is closed, the door and frame latching surfaces are projected and engaged in opposed surface-to-surface orientation. A direction of force resulting from an attempt to forcibly disengage the latching surfaces is directed through or close to the pivot access of the door latch. An override assembly is provided to force the frame latch to a retracted position when the door is opened. Auxiliary latch assemblies and corresponding frame latch assemblies are provided for coordinated latching and retraction when the push bar retracts the primary door latch. Dual latch assemblies are also provided. A solenoid mechanism may be employed to dog the push bar.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority of U.S. Provisional Patent Application No. 61/468,016 filed on Mar. 27, 2011, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    This disclosure relates generally to exit devices which are adapted for use in facilitating the egress from a building in an emergency situation such as fire. More particularly, this disclosure relates to exit bars which are mounted to exit doors and are depressible to retract a latch. 
         [0003]    Conventional exit bars to which the present disclosure relates employ a pivoted latch which is attached to a door. A fixed strike is mounted to the door frame. A horizontal bar is disposed across the door and is configured to retract the latch upon depressing the bar. The pivoted latch is a Pullman-type mechanism which is pivoted so that when it is pressed against the strike, it tends to rotate the latch into a closed position. The contacting surface of the latch is defined by a constant radius from the pivot axis. When the horizontal bar is depressed, the latch rotates into an opposite direction and the rotational movement of the latch facilitates releasing the latch even under a considerable pressure. 
         [0004]    The conventional-type of latching can be deficient when a substantial pulling force is applied from outside to the door. In this instance, the rounded surface of the latch pressed against the strike simply functions as a wedge, spreading apart the door and the door frame enough to disengage the strike and the latch essentially without moving anything else. In sum, the typical conventional latch can be fairly characterized as a compromise between a moderate degree of security and excellent safety. 
         [0005]    There are, however, numerous applications in which it is required that the latching devices be capable of withstanding tremendous pressure, such as may be applied to doors by hurricanes and tornadoes, while still providing an efficient and easy egress from the inside of the structure. In addition, security has become a significantly greater consideration, and there is a growing concern that it should not be unduly compromised. 
         [0006]    The subject exit system addresses problems associated with conventional devices by implementing a number of new approaches: 
         [0007]    First, both the latch and the strike are pivoted. The latch is pivoted in a way that, when under pressure to open the door, the latch pressed against the strike, which is blocked from rotation in a direction allowing door opening, tends to rotate in a direction to allow the door to open. However, the latch is configured in a “claw” like configuration, so that any would be rotating force theoretically goes through the center of rotation, and therefore is not effective in causing any rotation. In practice, the relationships may deviate from the theoretical model and the force is somewhat offset from the center of rotation. Consequently, there is a back up feature, blocking the claw-like latch, until the slightly depressed bar releases the blocking allowing rotation. When released, the latch is subject to two retracting forces—the pressure by the continuous movement of the bar and any force applied to the door from the inside or the outside in the direction of the opening. After the door is open and the bar is no longer pressed down, the door could be relocked. The one way pivoted strike allows re-latching. 
         [0008]    Second, the physical strength of a door/door frame system depends on the number of points where the door locks to the frame, regardless of the push bar design. Conventional related devices typically provide, at most, three points for a single door and two for a pair of doors. The proposed bar allows theoretically unlimited number of locking points all to be operated simultaneously by a single horizontal push bar. As practical constraints, the number of locking points would be limited by a force required for the bar to overcome resistance of the spring loaded latches and still be within activation force limits of regulatory codes. 
       SUMMARY 
       [0009]    Briefly stated, an exit bar system releasably secures a door to a door frame. The door is pivotal about a pivot axis between a closed and opened position and mounts a push bar on the secured side of the door. A door latching assembly mounted on the secured side of the door comprises a door latch mounted for pivotal movement about an axis parallel to the pivot access. The door latch has a door latching surface movable between a retracted position and a projected position. A frame latching assembly mounted to the door frame comprises a frame latch mounted for pivotal movement about an axis parallel to the frame. The frame latch has a frame latching surface movable toward a projected position. When the door is in the closed position relative to the door frame, the door and frame locking surfaces are projected and engaged in adjacent opposing surface-to-surface orientation such that a direction of force resulting from an attempt to externally forcibly disengage the latching surfaces is directed across or close to the axis of the door latch. 
         [0010]    In one embodiment, the door latching surface has a claw-like configuration, and the frame latching surface is generally complementary to the claw-like configuration. The door and frame latching surfaces in projected positions engage along an interface generally parallel to the door. The door latching assembly comprises dual transversely spaced door latches and the frame latching assembly also comprises two transversely spaced frame latches generally opposite the door latches. 
         [0011]    Upon depressing the push bar, the door latch is forced to a retracted position via a longitudinal translation of a slide assembly. The door latching assembly comprises a platform with a peripheral skirt defining a recess. A longitudinally reciprocating actuator is disposed in the recess. The actuator comprises a pair of transversely spaced extensions which each define a diagonal slot. 
         [0012]    A pair of actuating rods extend vertically relative to the latching assembly. A pin is received in each of the slots for vertically moving the actuator rods upon longitudinal movement of the actuator. A pair of transversely spaced, substantially identical latch housings each have a pair of transversely spaced upright walls. Each of the housings has a latch pivotally mounted via a pin received in an aperture of the walls. A coil spring is wrapped around each pin. The spring biases each of the latches to a generally projected position. 
         [0013]    A carrier is disposed between the housing walls and is longitudinally slidable relative to the housing. The carrier further connects with a contraction arm pivotally mounted to the door latch wherein longitudinal movement of the carrier forces the door latch to retract rearwardly into the latch housing. A longitudinally movable actuator is operatively connected to the push bar. The carrier is fastened to the actuator. 
         [0014]    The frame latching assembly comprises a frame latch biasing mechanism to bias the frame latch to a projected position. The frame latching assembly further comprises an override assembly which is biasable to overcome the frame latch biasing mechanism to retract the frame latch to a retracted position. The override assembly comprises a biasable member. The door latching assembly comprises a trigger stop, engageable against the member. Upon disengagement of the member and the trigger stop, the override assembly forces the frame latch to the retracted position. 
         [0015]    The trigger stop inhibits the overriding assembly when the door is in the closed position, thereby allowing the frame latch to project into engagement with the door latch. In one preferred embodiment, each door latch assembly and each frame latch assembly comprise a pair of transversely spaced cooperative latches. The overriding assembly comprises a coil spring with an intermediate U-shaped portion which rotatably biases the member which is one embodiment is a drive arm. The drive arm is engageable with a trigger stop to inhibit the overriding assembly. 
         [0016]    A multi-point exit device assembly releasably secures a door to a door frame. A primary latch assembly comprises a projectable door latch located on a secured side of the door. A primary frame assembly is engageable by the door latch. A retraction assembly disengages the door latch from the frame assembly and comprises a set of first cams. Two auxiliary latch assemblies, one located above and one located below the primary latch assembly are mounted adjacent the vertical edge of the door. The auxiliary latch assemblies each comprises a projectable auxiliary latch and a second follower. Two auxiliary frame assemblies are each engageable by an auxiliary latch. 
         [0017]    An electric dogging mechanism can be used with an exit device having a latch operatively connected to a push bar mechanism comprises a base plate. The push bar mechanism is mounted to a base plate and operates a latch with an extended latch position and a retracted latch position for the exit device. A holding sub-assembly is attached to the base plate for holding the push bar mechanism in a depressed position and thereby holding the latch in the retracted position. The holding sub-assembly comprises a solenoid plunger connected to the push bar mechanism and a solenoid for holding the push bar mechanism in a depressed position. The push bar is elongated and the plunger and push bar generally longitudinally align. 
         [0018]    An electromechanical assembly is adapted for incorporation with an exit device having a latch and a push bar mechanism operatively connected to the latch for moving the latch into a retracted position when depressed. An electromechanical assembly comprises a solenoid plunger movable independently from the push bar mechanism and operatively connected to the latch the plunger upon power being supplied to the solenoid moves the latch into a retracted position without depressing the push bar. The latch can be retracted independently by the push bar assembly and the electromechanical assembly. The electromechanical assembly is located in a housing for the exit device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view, portions removed, of an exit device as mounted to a door and latched to a door frame on the secured side of the door; 
           [0020]      FIG. 2  is an exterior side elevational view of the opposite side of the door and door frame of  FIG. 1 ; 
           [0021]      FIG. 3  is an enlarged sectional view of a portion of the exit device door and door frame of  FIG. 1  taken from the side of  FIG. 2 ; 
           [0022]      FIG. 4  is a fragmentary enlarged sectional view of the exit device of  FIG. 1  in a latched mode; 
           [0023]      FIG. 5  is a fragmentary interior sectional view of the exit device of  FIG. 4  illustrated in a released mode; 
           [0024]      FIG. 6  is an enlarged sectional view of the exit device of  FIG. 4  as installed to a door latch and a door frame; 
           [0025]      FIG. 7  is a side view, portions removed and portions broken away, of the exit device of  FIG. 1 ; 
           [0026]      FIG. 8  is a sectional view taken along the line  8 - 8  of  FIG. 7 ; 
           [0027]      FIG. 9  is a fragmentary sectional view taken along the line  9 - 9  of  FIG. 7 ; 
           [0028]      FIG. 10A  is a perspective view, portions removed, of the exit device and door latch assembly illustrating the latched mode thereof; 
           [0029]      FIG. 10B  is a perspective view, portions removed, of an exit device and latch assembly of  FIG. 10A  illustrating the exit device in a release mode; 
           [0030]      FIG. 11A  is a rear perspective view, portions removed, of the exit device and latching mechanism for the exit device of  FIG. 1 ; 
           [0031]      FIG. 11B  is a rear elevational view, portions removed, of the exit device and latching mechanism for the exit device of  FIG. 1 ; 
           [0032]      FIG. 11C  is a front elevational view, portions removed, of the exit device and latching assembly for the exit device of  FIG. 1 ; 
           [0033]      FIG. 12  is a rear perspective view, portions removed, of the exit device and latching assembly of  FIG. 1 ; 
           [0034]      FIG. 13  is an enlarged fragmentary rear view of the exit device and latching assembly of  FIG. 12 ; 
           [0035]      FIG. 14  is a perspective view, portions removed, of the exit device, latching mechanism and the latch assembly of  FIG. 1  as installed on a portion of a door and a portion of a door frame; 
           [0036]      FIG. 15A  is an exploded view of a door frame latching assembly employed with the exit device of  FIG. 1 ; 
           [0037]      FIG. 15B  is a partially assembled perspective view of the door frame latching assembly of  FIG. 15A  in retracted latch mode; 
           [0038]      FIG. 15C  is a fully assembled perspective view of a door frame latching assembly of  FIG. 15A ; 
           [0039]      FIG. 15D  is an enlarged frontal view of the door frame latching assembly of  FIG. 15C  with the cover removed; 
           [0040]      FIG. 15E  is a sectional view of the subassembly of  FIG. 15D  taken along the line of E-E thereof; 
           [0041]      FIG. 15E  is a sectional view of the subassembly of  FIG. 15D  taken along the line F-F thereof; 
           [0042]      FIG. 15G  is a sectional view of the subassembly of  FIG. 15D  taken along the line G-G thereof; 
           [0043]      FIG. 15H  is a partially assembled perspective view of the door frame latching assembly of  FIG. 15A  in a projected latch mode; 
           [0044]      FIG. 16A  is a sectional view of the door frame latching assembly of  FIG. 15A  together with portions of a door frame, a door, and the door latching assembly with the door illustrated in a pre-closing position; 
           [0045]      FIG. 16B  is a sectional view of the frame latching assembly of  FIG. 16A  and the portions of the door frame, door and door latching assemblies of  FIG. 16A  with the door illustrated in a subsequent closing position just prior to closing of the door; 
           [0046]      FIG. 16C  is a sectional view of the frame latching assembly of  FIG. 16A  and the portions of the door frame, door and door latching assemblies of  FIG. 16A  with the door in the closed position. 
           [0047]      FIG. 17A  is a perspective view, portions removed, of an alternative latching assembly which can be employed for the exit device of  FIG. 1 ; 
           [0048]      FIG. 17B  is a perspective view of the latching assembly of  FIG. 17A ; 
           [0049]      FIG. 18  is a perspective view, portions removed, illustrating a solenoid operating mechanism which can be incorporated into the exit device of  FIG. 1 ; 
           [0050]      FIG. 19  is a perspective view, portions removed, of an electromechanical assembly which may be incorporated into the exit device door frame and door of  FIG. 1  as installed on portions of a door and a door frame; and 
           [0051]      FIG. 20  is a side elevational view, portions removed, of the electromechanical assembly with the exit device as illustrated in  FIG. 19 . 
       
    
    
     DETAILED DESCRIPTION 
       [0052]    With reference to the drawings wherein like numerals represent like parts throughout the several figures, an exit device which is adapted for heavy duty high security applications is generally designated by the numeral  10 . The exit device  10  is installed on an exit door  12  at the secured side  14  and latches to a door frame  16 . The exterior side  18  of the door  12  may include a key operated latch  19 . 
         [0053]    In general, the exit device  10  comprises a panic bar assembly  20  which operates a principal door latching assembly  22 . The latching assembly  22  optionally, via a connecting rod  23 , functionally connects with an auxiliary upper latching assembly  24  and via a connecting rod  25  with an auxiliary lower latching assembly  26 . Each of the door latching assemblies  22 ,  24  and  26  latch with a corresponding frame latching assembly  32 ,  34  and  36 , respectively, each of which is mounted to the inner portion of the door frame  16  adjacent the edge of the door when the door is in the closed position illustrated in  FIG. 1 . Door latching assemblies  24  and  26  are optional and the panic bar and latching assemblies  20  and  22  may assume various alternative forms, as will be further described herein. The door frame latching assemblies  32 ,  34  and  36  likewise may assume various forms, each of which includes projecting latch members which extend for interengagement by the corresponding projecting latch members on the latching assemblies. 
         [0054]    The panic bar assembly  20  includes an elongated base  28  ( FIGS. 4 ,  5 ) which mounts to the door and functionally connects with the dual latching assembly  22  which is mounted to the door adjacent the open edge thereof. The base  28  has opposed elongated sides and an open end and top. An elongated bar  40  is mounted to the top of the base and is typically biased so that it is in an outer position spaced from the door. Upon depression of the bar  40 , a longitudinally slidable assembly causes a longitudinal translation of a slide member  60  which forces a pair of bifurcated claw-like latches  42  from the protracted closed latched position of  FIG. 4  to the retracted released position of  FIG. 5 . 
         [0055]    A generally U-shaped bracket  52  is disposed in fixed relationship to the base  28  (and the door). The bracket  52  mounts a pin  54  with a transfer link  56  pivotally connected to an actuator  58  at an intermediate position thereof. A second end of the actuator  58  connects via a pin  62  to an upright bracket  64  of the slide member  60 . The upper end of the transfer link  56  is pivotally connected to a panic bar mounting bracket  66 . The panic bar  40  is mounted over the bar mounting bracket  66 . When the bar  40  is depressed downwardly, the actuator  58  is forced to pivot downwardly thereby resulting in the slide member  60  moving to the left in  FIG. 5 . The opposed end of the slide member connects and operates with the dual latching assembly  22 . 
         [0056]    The panic bar assembly  20  is preferably mounted to the door via fasteners which extend through openings in the base  28 . In addition, an anchor plate  70  connects with a standoff  72  extending through a bore ( FIG. 9 ) in the door. The standoff  72  has an internal threaded surface which receives and mates with a threaded fastener  74  extending through the base. The fastener draws in the standoff and anchor plate  70  so that the anchor plate engages the exit side  18  of the door as, for example, illustrated in  FIG. 2 . 
         [0057]    The door latching assembly  22  comprises a platform  100  with a peripheral skirt  102 . Upon installation, the peripheral edge of the skirt  102  engages against the secured side  14  of the door. The platform  100  has a rear extension  104  which is received by the forward end of the base  28  and is secured therewith. The underside of the platform  100  forms a recess  106  for a longitudinally reciprocating actuator plate  110 . With reference to  FIGS. 11A and 11B , the actuator plate  110  includes a central longitudinal connector  112  and a pair of wings  114  which extend at 45° angles to a central transverse cross portion  116  and the longitudinal connector  112 . The plate  110  slides longitudinally generally in the direction of the arrows of  FIG. 11B . 
         [0058]    The top side of the platform mounts a pair of substantially transversely spaced identical latch housings  120 . Each housing  120  has a pair of transversely spaced upright walls  122 . Each wall has a pair of longitudinal collinear slots  124  and  126  and an arcuate upper cam slot  128  which align with opposed substantially identical corresponding slots in the opposite walls. The latch  42  is pivotally mounted via a pin  130  which is received in a lower aperture proximate the forward edge of the frame. The latch has a limit shoulder  44  adjacent the pin mounting position. The latch preferably has a bifurcated claw-like form with a central recess  43 . A coil spring  132  is received in a lower recess of the latch and wraps around the pin for biasing the latch to a generally forward position which projects through an upper frontal opening  134  in the housing  120 . There is a significant central platform area  108  between the latch housings  120 . The area  108  can be used to accommodate additional features as illustrated in  FIGS. 19-20 . 
         [0059]    With reference to  FIG. 14 , a trigger  136 , which has a forwardly projecting surface  138 , is mounted to a frontal central portion of the platform  100 . A cover mounts over the platform  100  and is secured by fasteners  109 . The cover has two transversely spaced openings for the latches  42  and a central smaller frontal opening for the trigger  136 . If required, the cover may also have side openings to accommodate actuating rods  23  or  25 . 
         [0060]    An inverted U-shaped carrier  140  is nested between the housing walls  122  and is connected to each housing  120  through each wall via a pair of pins  142  and  144 , one received in the rear slot and one received in the forward slot. The forward end of the carrier has an upper shoulder  141  which is engaged by the latch shoulder  44  to rigidly reinforce the projected position of the door latch  42 . The rear pin  144  also exteriorly mounts a pair of spaced retraction arms  146  which are pivotally connected to the pin. The opposed end of each retraction arm  146  is pivotally mounted via a pin  148  which extends through a transverse bore in the bifurcated portions of the latch  42 . The pin  148  follows the arcuate cam slot  128  in the walls of the opposed side. 
         [0061]    The underside of the carrier is fastened to each wing  114  of the actuator plate  110  by screws  118 . When the actuator plate is rearwardly retracted, the carrier  140  rearwardly moves and the retraction arms  146  each pull the latch in a coordinated action so that each latch  42  pivots and slides both rearwardly and downwardly. 
         [0062]    It will be appreciated that there is an identical structure at the opposing sides of the platform so that each latching assembly  22  essentially provides for two transversely spaced controlled projectable and retractable latches  42 . 
         [0063]    With reference to  FIGS. 11A-11C , the actuator plate  110  for the central principal latching assembly  22  includes a pair of extensions  150  which project perpendicularly from each of the wings  114 . The extensions contain a 45° diagonal slot  152  and function as a guide or cam surface for movement of a pin  153  or  155  in the slot. The pins  153  and  155  are fixed to and radially extend from adjustable connector modules  160 . The connector modules  160  are transversely slidable for displacing the rods  23  and  25 , respectively, to thereby actuate the upper and lower auxiliary latching assemblies  24  and  26 , respectively. 
         [0064]    The top of the platform  100  includes two sets of transversely spaced, upstanding parallel flanges  170 . Each set of flanges forms a receiver. Each of the flanges has a transverse slot  172 . Each connector module  160  includes a carrier  162  with a restricted nose-end  164  defining a reduced opening. The carrier  162  is mounted to the flanges by a pair of pins  174  and  176  which slide along the slots  72  so that the carrier moves transversely relative to the upstanding flanges  170 . 
         [0065]    The end of the actuating rod  23  or  25  is connected to the carrier by means of an adjustable hex head screw  178 . The hex head is received in the carrier  162 . The shank threads into the end of the rod with the threaded shank of the screw extending through the restricted nose-end  164  while the hex head is limited or captured by the nose-end  164 . Thus, movement of each carrier  162  causes the associated rod to transversely move. The proximal end of the carrier mounts the pins  153  or  155 . The nose-end  164  defines the outer limit for movement of the rod. The inner movement is defined by the innermost position of the inner pin and the end of slot  172  subject to the threaded adjustment of screw  178 . 
         [0066]    As the actuator track plate  110  is retracted, the pins  153  and  155  traverse the corresponding diagonal slots  152  and cause the actuating rods  23  and  25  to reciprocate inwardly and outwardly to thereby retract a corresponding actuator plate of the upper and lower latching assemblies  24  and  26 , as will be described below. 
         [0067]    It will be appreciated that for installations wherein the auxiliary latching assemblies  24  and  26  are not required, the upstanding flanges on the platform  100  as well as the connecting assemblies for the rods, are not required, such as, for example, the embodiments illustrated in  FIGS. 10A-10B . 
         [0068]    Auxiliary latching assemblies  24  and  26  (and any other latching assemblies that may be employed) have substantially the same structure and function as latching assembly  22  except that the latches are not operated by the panic bar, but by a complementary orthogonally driven movement of a corresponding actuator rod  23  or  25 . 
         [0069]    A representative auxiliary latching assembly is illustrated in  FIG. 13 . The principal difference compared to latching member  22  is the structure of the actuating plate  180 . The plate  180  has a pair of diagonal slots  182  (45° relative to a longitudinal axis) which functions in a complementary manner as compared to the corresponding plate  110  and slots  152 , as previously described for central primary latching assembly  22 . Slots  182  essentially function as followers. The upper end of rod  23  includes an adjustable hex head screw received in a carrier  190  which carries a pin  192 . The pin  192  essentially functions as a cam. Movement of the carrier due to transverse displacement of the actuating rod  23  drives the pin  192  to slide along the slot  182  and therefore forces the actuating plate  180  to move longitudinally in the direction of the  FIG. 13  arrow. 
         [0070]    The actuating plate  180  is fastened to the corresponding carriers  140  for the latches  42  by means of screws  184 . The top of the corresponding platform  100 A includes a pair of latch housings  120  and projectable latches  42  which are substantially the same structure and are retracted and extended in the same fashion as previously described for the corresponding structures for latch mechanism  22 . A trigger  136  is also provided. Thus it will be appreciated that depressing the panic bar  40  which actuates latching assembly  22  correspondingly also results in a displacement of a connecting actuating rod  23  and/or  25  which functions to also retract the latches of each of the corresponding auxiliary latching assemblies  24  and/or  26 . 
         [0071]    It should be appreciated that additional auxiliary latching assemblies could be provided and operatively connected via an actuating rod and carrier assembly driven via an upper pin  192 . Multiple additional auxiliary latching assemblies and actuating rods (which operatively connect with auxiliary latching assemblies  24  and/or  25  locking assemblies) could be employed to provide multiple latching locations. 
         [0072]    With reference to  FIGS. 17A and 17B , door frame latch assembly  32 A includes, in one embodiment, a multi-walled support frame  200  which is secured to the edge of the door frame  16  opposite a door latching assembly in surface-to-surface engagement by screws  202  secured through openings of the frame. The door frame latch assembly  32 A comprises a pair of transversely spaced yokes  210  which include upstanding brackets. A projectable latch  220  has a configuration generally complementary to the claw-like configuration of the door latches  42 . One end of the frame latch  220  includes a throughbore which receives a mounting pin  222  extending through opposed sides of the yoke brackets. A torsion spring  224  wraps around a central portion of the pin  222  between a pair of spacers  226 . Spring  24  bears against each latch member  220  to outwardly bias the latch in a projected position from the yokes so that the door frame latch  220  and the door latch  42  both project to interengage and essentially latch the door, such as, for example, illustrated in  FIG. 6 . 
         [0073]    A cover  230  ( FIG. 15A ) with a pair of openings  232  for each latch member is mounted over the support frame  200 . The cover is secured by a pair of screws  234  which thread into a spacer boss  236 . 
         [0074]    It will be appreciated that any attempt to separate the door from the latching engagement is generally distributed through or slightly offset from the latch pin  130 . Consequently, the cooperative latch mechanisms do not exhibit the wedge-type separation susceptibility as is common in many conventional-type latching mechanisms. When the door latch  42  is retracted, the door is free to pivot relative to the door frame latch and the door can thus be opened. 
         [0075]    With reference to FIGS.  14  and  15 A- 15 H, for some preferred embodiments, the door frame latch assembly  32 B includes an override assembly  250  which is functionally disposed between the projecting spring biased latches  220  and, upon triggering, functions to apply an override force for returning the latches  220  to a retracted position within the cover  230 . In this regard, the override assembly  250  has a greater spring force than that provided by the torsion springs  224  which function to normally project the latches to the projected position. The override assembly  250  is positioned in the central frame cradle  212  between the yokes  210 . 
         [0076]    A U-shaped bracket  252  is attached to a sidewall  214  of the support frame  200 . The bracket has a pair of opposed openings which receive a pin  254 . A torsion spring  256  is configured to form a medial catch  258  is mounted about the rod and engages the back of a drive arm  260  to exert a pivotal biasing force on the drive arm  260 . Spacers  262  may be placed at each of the ends of the springs to generally center the spring  256  with the bracket  252 . 
         [0077]    An actuator bar  270  fixed with the drive arm  260  has a pair of opposed flappers  272  which engage pins  274  projecting from the side of the latch members  220 . A stop  276  projects into the recess to provide a limit for the flappers  272 . When the drive arm  260  is activated by removing the blocking element from the latching assembly  22 , the drive arm is free to project under the force of the spring  256  and moves the actuating member to pivotally move the pins  274 , thereby causing the latch members  220  to overcome the bias of the springs  224  and retract into the housing. The drive arm  260  is accessible via a central slot  238  in the cover  230 . The cover  230  is mounted over the door frame latch assembly base support frame. The slot  238  is positioned and dimensioned to receive and be engaged by the trigger  136  mounted with the door (see  FIG. 14 ). Upon release of the actuator arm  260 , the force of the spring  256  outwardly retracts the latches  220  into the cover as illustrated in  FIGS. 15B and 15C . 
         [0078]    With reference to  FIGS. 16A-16C , the actuator bar  270  fixed with the drive arm  260  has a pair of opposed flappers  272  which engage pins  274  projecting from the side of the latches  220 . The entire sub-assembly is biased by means of the spring  256  towards pins  274  therefore pushing the latches  220  into a retracted position. The force of spring  256  is stronger than the forces of springs  224  which bias the latches into opposite outward projected positions. Thus, in the retracted position shown in  FIG. 16A , when the door is still open and the trigger  136  attached to the door latching assembly has penetrated the slot  238  to a position wherein it just engages the drive arm  260 , the latches  220  are still retracted. 
         [0079]      FIG. 16B  shows a more advanced door position wherein the door is nearly closed and about to be latched. Trigger  136  pushes the drive arm  260  further downwardly (clockwise) releasing the pins  274  from the pressure created by the spring  256 , thereby allowing the springs  224  to rotate the latches  220  somewhat (counter-clockwise) out of the housing restricted only by the presence of the door latches  42 , which are now fixed in a stable pivot position by the engagement of latch shoulder  44  and carrier shoulder  141 . 
         [0080]      FIG. 16C  shows the door in a theoretically closed position. The fixed door latches  42  are advanced beyond the tips of the latches  220 , allowing the springs  224  to complete the clockwise swing of the frame latches into an upright projected position. The door latches  40  and the frame latches  220  have been mutually latched. The override assembly  250  is inhibited in retracting the latches  220  by the engagement of the trigger  136  and the actuator arm  260 . 
         [0081]    With reference to  FIGS. 7 ,  9  and  18 , the position of the panic bar (which is mounted over bracket  66 ) may also be controlled by an electromechanical assembly  300 , such as one that employs a solenoid  310 . The solenoid  310  has an actuator arm  312  with a transverse cross-pin  314 . A slidable coupler  320  includes a pair of opposed longitudinal slots  322  which receives the cross-pin  314 . The coupler  320  connects with slide member  60 . The ends of the slot  322  define the range of longitudinal displacement of the coupler. The solenoid  370  may be electrically actuated from a remote location to maintain the panic bar at the depressed (dogged) position once the panic bar is initially depressed. During normal hours, egress through the door does not require actuation of the panic bar to release the latches  42  after the initial depression of the panic bar  40 . The solenoid has sufficient power to maintain the depressed panic bar/retracted latch condition. The solenoid  310  may be wired into the overall fire safety system for the building so that in case of a fire, the door will automatically latch. 
         [0082]    With reference to  FIGS. 19 and 20 , another electromechanical override assembly  350  may be employed with one or two solenoids  360  which are mounted to the central area  108  between the two latch housings  120 . A slidable bridge  370  connects between the actuator arm  110  and the slide member  60  governed by the panic bar  40 . The bridge has opposed longitudinal slots  372 . The solenoids each have actuators  362  which engage a slidable coupler  364  having a cross-pin  366  which is received in opposed slots  372 . The solenoid actuators  362  bear against the cage  364  to provide an independent override unlatched position for the latches  42  by rearwardly moving along the slots  372 . The ends of the slots  372  function as limits for movement of the bridge  370 . 
         [0083]    The solenoids  360  can be employed to provide for the remote actuation and automatic de-actuation (retraction) of the latches  42  at various times throughout the working day. The panic bar  40  for this assembly is also depressible throughout the implementation of the independent retraction by the engaged solenoids. The solenoids  360  can also be wired into the overall safety system for the building.