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BACKGROUND OF THE INVENTION 
     This invention relates generally to controlling the unlocking of doors, and more particularly to unlocking of double doors, as from opposite sides thereof. 
     There is need for compact, simple, durable, and efficient door unlocking operation, and method, particularly when side-by-side independently openable doors are employed, and unlocking is required at opposite sides of such doors. This is of particular need when simultaneous unlocking of both such doors is required, along with capability to unlock only one door from one side, and to unlock both doors from the opposite side. 
     SUMMARY OF THE INVENTION 
     It is a major object of the invention to provide door unlocking apparatus and methods of operation, to meet the above need. Basically the method of the invention includes: 
     a) providing two rotary input devices, 
     b) providing first means responsive to rotation of one of the devices, to unlock one of the doors, 
     c) providing second means responsive to rotation of the other of the devices to unlock both of the doors, 
     d) said second means operatively coupled to such first means, to activate such first means after predetermined rotation of the other device. 
     As will be seen, the two input devices may be provided to have a common axis of rotation, for simplicity and compactness. The one device typically comprises a rotatable knob, and the other device comprises a rotatable handle lever, one being at one side of the doors, and the other at the opposite side of the doors. 
     Another object includes the provision of such apparatus configured to bodily move, endwise, vertical lock rod means to lock and unlock the doors in response to rotation of said other device, the lock rod means operatively coupled to one or both of the first and second means. Further, the first means may include latch mechanism located for release to control door unlocking, in response to rotation of either of such devices. 
     These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which: 
    
    
     
       DRAWING DESCRIPTION 
         FIG. 1  is an elevation showing twin or double doors, at one side thereof and in locked condition, and apparatus to control locking and unlocking; 
         FIG. 2  is like  FIG. 1 , but showing the doors in unlocked condition; 
         FIG. 3  is an elevation showing the doors of  FIG. 1 , viewed at the opposite side thereof, the doors being locked; apparatus for controlling locking and unlocking of only one door also being shown; 
         FIG. 4  is an elevation like  FIG. 3 , but showing the doors in unlocked condition; 
         FIG. 5  is an enlarged elevation taken on lines  5 - 5  of  FIG. 3 ; 
         FIG. 6  is an elevation taken on lines  6 - 6  of  FIG. 5 ; 
         FIG. 7  is an elevation taken on lines  7 - 7  of  FIG. 5 ; 
         FIG. 8  is an enlarged view showing elements of  FIG. 7 , with a latch element in raised (up) position; 
         FIG. 9  is a view like  FIG. 8 , with the latch element shown in down position; 
         FIG. 10  is a perspective view showing rotatable cams, providing lost motion (see also  FIGS. 9 and 22   a;    
         FIG. 11  is an elevation taken on lines  11 - 11  of  FIG. 5 , and showing mechanism in blocked position, corresponding to  FIG. 3 ; 
         FIG. 12  is a view like  FIG. 11 , but showing the mechanism in unblocked position, corresponding to  FIG. 4 ; 
         FIG. 13  is an elevation taken on lines  13 - 13  of  FIG. 5 , and showing mechanism in blocked position; 
         FIG. 14  is a view like  FIG. 13 , but showing the mechanism in unblocked position; 
         FIG. 15  is an elevation taken on lines  15 - 15  of  FIG. 5 , and showing mechanism in blocked position; 
         FIG. 16  is a view like  FIG. 15 , but showing mechanism in unblocked position; 
         FIG. 17  is a horizontal section, taken on lines  17 - 17  of  FIG. 8 ; 
         FIG. 18  is a fragmentary vertical section taken on lines  18 - 18  of  FIG. 17 ; 
         FIG. 19  is a horizontal section taken on lines  19 - 19  of  FIG. 14 ; 
         FIG. 20  is a vertical section showing cam actuation of a lock rod, with that rod in lowered, (extended) door locking position, the cam located on a multifunctional shaft; 
         FIG. 20   a  is an enlarged vertical and fragmentary section, taken on line  20   a  of  FIG. 20 ; 
         FIG. 21  is like  FIG. 20 , but showing the cam in lower lock rod elevated (retracted) position; 
         FIG. 22   a  is an exploded view of certain lock apparatus elements; and 
         FIG. 22   b  is an exploded view of other lock apparatus elements. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , twin, side-by-side doors are indicated at  10  and  11 , with vertical frame members  12 - 15 , and top cross frame member  16 . Door  10  is typically hinge connected to frame member  13 , to swing between open and closed position; and door  11  is typically hinge connected to frame member  15 , to swing between open and closed positions. See hinges  90 . Door  10  includes frame member  12  so that frame member  12  moves with respect to frame members  13 ,  16  when door  10  is moved between opened and closed positions. Door  10  may be considered as an “active” door, i.e. normally used for in and out access. Door  11  includes frame member  14  so that frame member  14  moves with respect to frame members  15 ,  16  when door  10  is moved between opened and closed positions. Door  11  may be considered as an inactive door, to be opened in an emergency. Also, the  FIGS. 1 and 2  views are looking at the doors from the outside.  FIGS. 3 and 4  show the doors as they appear at the inside of a building, a rotary handle knob  18  being used to open active door  10 . In an emergency, handle lever  20 , pivoted at  21  to frame member  12  may be swung to quickly unlock both doors, enabling rapid exit from the building. 
     The knob  18  may be considered as representative of a rotary input device operable to unlock one of the doors; and the lever  20  may be considered as representative of a device to unlock both of the doors. In this regard, first means is provided to be responsive to rotation of knob  18  to unlock active door  10 ; and second means is provided to be responsive to rotation of the lever  20  to unlock both doors,  10  and  11 . 
     As will be seen, bodily endwise movable lock rod means is or are provided to lock and unlock the doors, in response to rotation of the knob  18 ; and also to unlock both of the doors in response to rotation of the handle or lever  20 . Such lock rod means typically may include an upper rod  22  and a lower rod  23 , endwise movable within door frame member  14  between locking position seen in  FIGS. 1 and 3 , and unlocking positions seen in  FIGS. 2 and 4 . Note the rod ends  22   a  and  23   a  which are carried into locking recesses  24  and  25  in  FIGS. 1 and 3 , and out of those recesses in  FIGS. 2 and 4 . As seen in  FIGS. 1-4 , the knob  18  and lever  20  may be at the same elevation. The handle lever also operates to cause a bolt  26  to frame member  12  to be retracted from a slot  26   a  in frame member  14 , when the lever is moved downward to unblock door  10  from locked position. See  FIG. 2 . 
     Extending the description to  FIGS. 5 and 6 , the knob  18  and handle may also have offset axes of pivoting  27  and  28  at the same vertical level, as indicated. 
       FIGS. 13 and 14  show the latching mechanism to include a transverse shaft  35  carried by and within hollow upright frame member  14 ; and a linkage operatively connecting the shaft to the upper and lower lock rods  22  and  23  extending vertically and movable endwise to lock and unlock the doors, in response to rotation of the shaft  35 . In  FIG. 13 , the shaft has been rotated counter-clockwise to cause rotary link  36  to extend slider  22   c  upwardly (moving rod  22  upwardly into door locking position) and to extend slider  23   c  downwardly (moving lower rod  23  downwardly into door locking position). 
     Link  36  has pin and groove slidable connections at  36   a  to slider  22   c , and at  36   b  to slider  23   c . In  FIG. 14 , the link  36  has been rotated by shaft  35  to retract the sliders and lock rods, to door unblocking positions, allowing door  11  opening and closing, relative to the frame member  12 .  FIGS. 15 and 16  show spring means, such as a tension spring  37 , connected at  38  and  39  to the lock rods, to positively urge them toward retracted position, in conjunction with shaft rotation, as by sudden unblocking rotary release of a blocking cam  40 , on shaft  35 . Therefore, when cam  40  is suddenly released to rotate, the locking rods are retracted, the spring  37  providing force acting through the mechanism to rotate that cam clockwise, in  FIG. 8 . 
     Referring again to  FIG. 8 , a latch or latch arm  45  carries a downward projection  46  swingable and biased clockwise into rotation blocking relation with the cam  40 . See biasing spring  47  urging arm  45  clockwise about pivot  48  so that ledge  46   a  on projection  46  bears on the cam surface, and drops into the position shown, engaging cam step shoulder  40   a , in  FIG. 8 . Ledge  46   a  is angled to be forcibly over-ridden by  40   a  in response to forcible turning at knob  18 . 
     When latch arm  45  is pivoted counter-clockwise, either by knob  18  rotation (to cause shoulder  40   a  to ride over the ledge  46   a ) or by handle lever  20  rotation to pivotally deflect the latch arm  45  counter-clockwise, to release blocking engagement of  40   a  and  46   a , the cam  40  suddenly releases and rotates, as referred to above allowing spring  37  to release the rods  22  and  23 . See  FIG. 9  in this regard. A guide lug  96  on  35  guides in a slot  97  in latch  45 , to keep  40   a  and  46   a  aligned. 
     Lever  20  rotation not only releases bolt connection at  26  and  26   a , of door  11  to frame member  12 , but also causes a projection  50  associated with that lever to rotate upwardly and actuate a slider  55 , at location  55   a  pushing it upwardly, as from  FIGS. 6 and 8  position, to  FIG. 9  position. The upper edge  55   b  of the slider, in  FIG. 9  has engaged the latch arm  45 , at cam surface  45   a  to pivot it clockwise as referred to above to unblock cam  40 . This also results in release and retraction of the locking arms  22  and  23  as described. Pivoting of the lever  20  also retracts projection or bolt  26  from captivation in frame  14 , allowing door  10  to be opened, along with door  11 . Cam  40  also has a lost motion rotation feature, to enhance positive door locking and unlocking. 
     When the lever  20  is manually released and returned to  FIG. 4  position, the slider  55  drops down, by gravity action, allowing the latch  45  to return to  FIG. 8  position, as the knob  18  is rotated to lock the doors. 
     Knob  18  is shown as mounted on a transverse shaft  60 , below shaft  35 , in  FIG. 6 . Shaft  60  is carried by frame member  14 , which enables the knob  18  to be positioned at the same vertical level as the lever  20 . Shaft  60  is operatively connected with shaft  35 , as via gears  62  and  63  on shafts  35  and  60 , and endwise movable rack  64 . 
     Referring now to  FIGS. 7 ,  11  and  12 , it will be observed that as lever  20  is manually rotated, the projection  50  is rotated upwardly, i.e. the throw movement of the projections. This movement is depended upon to cause the door locking rods  22  and  23  to be displaced from  FIG. 2  unlocking positions into  FIG. 1  locking positions. In accordance with a further object of the invention, displacement compensation means is provided for compensating the rotary movement of the lever  20  and projection  50  to the bodily movement of the locking rods. 
     As shown in  FIGS. 11 and 12 , such compensation means includes a first spur gear  150  operatively coupled to the knob  18 , via shaft  35 , and a second spur gear  151  on shaft  151   a . Gear  151  meshes with gear  150 , and is operatively coupled as via rack  153  to, or carried by, an element, such as slider  152  that is displaced upwardly in response to the throw movement of the lever and its projection  50 . In this regard, the first gear  150  has a number of teeth N 1 , and the second gear has a number of teeth N 2 , there N 1 /N 2  exceeds 1, creating the compensation, as gear  151  drives gear  150 . Thus, projection  50  drives rack  153  upwardly from  FIG. 12  to  FIG. 11  position, which rotates gear  151  to drive gear  150 , which rotates shaft  35 , effecting locking rod endwise movement, as described in connection with  FIGS. 13 and 14 . 
     As shown in  FIG. 5 , the generally closely compact, parallel relationship of components contributes to a high degree of utility in a doorway installation environment.

Summary:
The method of controlling unlocking of one or both side by side doors, that include providing two rotary input devices; providing a first mechanism responsive to rotation of one of the devices, to unlock one of the doors; providing a second mechanism responsive to rotation of the other of the devices to unlock both of the doors, the second mechanism operatively coupled to the first mechanism, to activate the first mechanism after predetermined rotation of the other device.