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CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims the benefit of U.S. Provisional Application No. 62/039,700, filed Aug. 20, 2014. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to mechanisms for electrically locking a door in a frame; more particularly, to an electrical door strike assembly having movable keeper arms for selectively retaining and releasing an associated door latch, and most particularly to an electric door strike assembly including a reinforcement feature to oppose the forces placed on the keeper arms by the door latch. 
       BACKGROUND OF THE INVENTION 
       [0003]    U.S. Pat. No. 8,454,063, entitled “Mode-Switchable Door Strike” (the &#39;063 patent), the relevant disclosure of which is herein incorporated by reference, discloses an electric door strike assembly of the type forming the basis of this invention. As shown, latch portions  22  of keeper arms  18  are configured in the electric door strike assembly to be contacted by and withstand the force of an extended door latch when an attempt is made to open the door while the electric door strike assembly is in its locked mode. 
         [0004]    When a wider keeper arm is needed in some installations in order to make contact with an extended door latch, a twisting force may be placed on the keeper arms and their associated pivots which may lead to unwanted strike assembly wear, and may even lead to an inoperative assembly thereby requiring reconstruction or replacement of the door strike, door latch or both. 
         [0005]    What is needed in the art is an electric door strike assembly wherein the keeper arms and associated pivots are reinforced by a reinforcing bracket to minimize, and preferably eliminate the twisting force placed on the widened keeper arms. 
         [0006]    It is a principal object of the present invention to provide a more durable electric door strike assembly. 
       SUMMARY OF THE INVENTION 
       [0007]    Briefly described, an electric door strike assembly in accordance with the present invention comprises a housing having a central cutout portion with an opening adapted to receive a latch of a door. First and second keeper arms are pivotably mounted on opposite first and second sides of the opening and have latch portions extending across the opening, and have a first position occluding the opening, which position may be locked or unlocked, and a second position pivotable from the first position which allows the latch to be withdrawn from the opening past the latch portions. In one aspect of the invention, the latch portions of the keeper arms extend above the body of the housing such that they are susceptible to rotating or twisting out of proper alignment with the housing. To minimize, or preferably prevent such rotation or twisting, a reinforcing bracket is mounted to pivots of the keeper arms and to the housing so as to constrain the keeper arms in their plane perpendicular to the plane of the housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
           [0009]      FIG. 1  is an isometric view from the right front showing a prior art electric door strike assembly with the cover removed for clarity (cover is removed and not shown in all views herein); 
           [0010]      FIG. 2  is a plan view of one end of the prior art electric door strike assembly shown in  FIG. 1 ; 
           [0011]      FIG. 3  is an isometric view of one end of the prior art electric door strike assembly shown in  FIG. 1 ; 
           [0012]      FIG. 4  is an isometric view from the right front showing an embodiment of the present invention; 
           [0013]      FIG. 5  is an isometric view from the right front of the embodiment shown in  FIG. 4  with the support bracket removed from the housing; 
           [0014]      FIG. 6A  is a cross-sectional view of the embodiment of the present invention taken generally along line  6 A- 6 A in  FIG. 5 ; and 
           [0015]      FIG. 6B  is a cross-sectional view of the embodiment of the present invention taken generally along line  6 B- 6 B in  FIG. 4 . 
       
    
    
       [0016]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate currently preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
       DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    Referring now to  FIGS. 1 through 3 , a prior art electric door strike assembly  10  comprises a housing  12  mountable to a door frame (not shown). The prior art electric door strike assembly  10  is to be regarded as exemplary in nature and does not serve to limit application of the present invention to embodiments solely thereto. The mounting of housing  12  may be either surface mounting or recessed mounting, as is well known in the prior art. A cover (not shown) protects the interior of housing  12  from tampering as well as from dirt, dust, and the like. Housing  12  includes an opening or cutout portion  14  adapted to receive a latch (not shown) of a door (not shown) as is also known in the prior art. Cutout portion  14  is generally defined by housing rear wall  12 B and cutout side walls  12 C,  12 D. 
         [0018]    The referenced prior art electric door strike assembly shown in  FIG. 1  preferably comprises first and second mirror-image locking mechanisms  16  mounted to housing  12  and disposed symmetrically about cutout portion  14 . For simplicity and clarity in presentation, general reference may be made to only one of the two mirror-image mechanisms  16 , but such reference should be considered as being equally applicable to both except as otherwise noted. The use of a pair of keeper arms  18  is presently preferred over a single keeper arm as each keeper arm of the pair is subject to only half of any incoming force which, in turn, means that the strength of the device is essentially doubled. 
         [0019]    Opposing keeper arms  18  are mounted at keeper arm pivots  20  positioned proximate the midpoint of keeper arms  18  and are positioned proximate to cutout portion  14 . When keeper arms  18  are oriented in a closed position wherein their longitudinal axes are aligned in a plane generally parallel to the plane created by front housing wall  12 A, latch portions  22  of arms  18  extend into and occlude cutout portion  14  thereby retaining the door latch within cutout portion  14 . As is known in the prior art, when the door is moved closed, upon the door latch contacting the latch portions, the door latch retracts against a return spring force and is then free to be received by cutout portion  14 , even when keeper arms  18  are in closed positions. That is, when the door is shut into a frame supporting strike assembly  10 , the door latch retracts to allow passage past latch portions  22  but then snaps into cutout portion  14 . Once in cutout portion  14  and when keeper arms  18  are in closed positions, the latch is trapped in cutout portion  14  and the door cannot be opened. Such keeper and strike action are well known in the art and the operation thereof will not be further discussed herein. 
         [0020]    Keeper arms  18  are adapted to engage with transmission levers  24  mounted to housing  12  by transmission lever pivots  26 . The axes of rotation of transmission lever pivots  26  are parallel to and aligned vertically with the axes of keeper arm pivots  20 . 
         [0021]    Prong  28  is positioned on each keeper arm  18  opposite latch portion  22 . Prong  28  is received within a fork  30  positioned on a corresponding side of transmission lever  24  when keeper arm  18  is in a closed position. 
         [0022]    Keeper arms  18  are resiliently urged to the closed position by springs (not visible) which may be mounted on pivots  20 . One arm of each spring may engage a keeper arm  18  on its prong side and the other arm may engage a sidewall of cutout portion  14 . Thus, when prongs  28  are released from forks  30 , keeper arms  18  are held in the closed position only by the springs. To open the door, a user simply pushes against the door, causing the latch to rotate keeper arms  18  against the springs. Once the latch clears keeper arms  18 , the keeper arms rotate back to the closed position under the urging of the springs. Further, to best position each transmission lever  24  to receive prong  28 , a compression spring (not shown) may be mounted on one end thereof to fork  30  and at the other end thereof to housing  12  proximate fork  30 . The compression springs urge transmission levers  24  rotatably away from housing  12  to best position fork  30  to receive prong  28 . 
         [0023]    A release lever  34  is used to control the motion of each transmission lever  24  from a rotatable state to a locked state. Release lever  34  is mounted at one end thereof to housing  12  by release lever pivot  36 . The axes of rotation of release lever pivots  36  are parallel to but offset laterally from the axes of both keeper arm pivots  20  and transmission lever pivots  26 . The other ends of release levers  34  engage ends  38  of transmission levers  24  opposite forks  30 . Solenoid  52 , when energized, moves release lever  34  into either engagement with or disengagement from transmission lever  24 , thereby locking or unlocking the transmission lever so as to allow the keeper arm to move from a latch-blocking position under a force exerted by the extended door latch when the door is opened. The conjunctive operation of the solenoid, release lever, transmission lever and keeper arm is fully described in the incorporated-by-reference &#39;063 patent and need not be described in further detail here. 
         [0024]    In the electric door strike assembly described above, the width (W) ( FIG. 1 ) of the latch portion  22  of the keeper arms are such that the door-opening force (F) ( FIG. 3 ) placed on the keeper arms by the associated door latch when the keeper arms are locked are directed generally through keeper arm pivots  20  and the transmission lever and release lever with little or no twisting moment placed on the keeper arms and keeper arm pivots. However, in some instances, in order to accommodate an associated latch that would have a contact point with the keeper arms at a higher point on the keeper arm, the width (W′) of the keeper arms must be increased as shown in  FIG. 4 . The resulting door-opening force (F′) places a twisting moment (M) on the keeper arm pivots ( FIG. 6B ), 
         [0025]    Referring now to  FIGS. 4-6B , an embodiment  10 ′ of an electric door strike assembly of the present invention is shown, wherein all elements are identical with those of first embodiment  10  except latch portions  22 ′ of opposing keeper arms  18 ′ have a width W′ greater than width W of latch portions  22  (see  FIG. 1 ) and the provision of reinforcing bracket  60  which will be discussed in more detail below. Electric door strike assembly  10 ′ is exemplary of a door strike amenable for including keeper arms  18 ′ and is in no way meant to limit application keeper arms  18 ′ solely to this embodiment. It is to be understood by those skilled in the art that keeper arms  18 ′ may be proportioned to function within any suitable door strike device irrespective of how the solenoid connects to the keeper arm or arms. 
         [0026]    In operation, similar to electric door strike assembly  10  described above, housing  12  includes a cutout portion  14  adapted to receive a latch (not shown) of a door (not shown) as is also known in the prior art. Cutout portion  14  is generally defined by housing rear wall  12 B and cutout side walls  12 C,  12 D. Door strike assembly  10 ′ includes opposing keeper arms  18 ′ mounted at keeper arm pivots  20  positioned proximate the midpoint of keeper arms  18 ′ and are positioned proximate to cutout portion  14 . When keeper arms  18 ′ are oriented in a closed position, for instance as shown in  FIG. 4  wherein they lie in an x-y plane generally parallel to the plane created by front wall  12 A and perpendicular to the x-z plane defined by bottom surface  12 E of housing  12 , latch portions  22 ′ of arms  18 ′ extend into and occlude cutout portion  14  thereby retaining the door latch within cutout portion  14 . 
         [0027]    As can best be seen in  FIGS. 6A and 6B , keeper arm pivots  20  each generally comprise a top flange portion  21  and a bottom threaded post portion  23 . Bottom threaded post portion  23  includes integral male threads  23 A which are configured to engage with corresponding female threads  13 A within post member  13  which is integrally formed on housing  12  to secure keeper arm pivot  20  to housing  12 . Top flange portion  21  includes a figured recess  21 A configured to selectively receive a corresponding tool so as to enable tightening of bottom threaded post portion  23  to post member  13 . Each keeper arm pivot  20  further includes a shaft portion  25  situated between top flange portion  21  and bottom threaded post portion  23 . Shaft portion  25  is configured to engage keeper arm  18 / 18 ′ as a bearing surface such that keeper arm  18 / 18 ′ is constrained between top flange portion  21  and post member  13  while being able to pivot about shaft portion  25 . 
         [0028]    With continued reference to  FIGS. 4-6B , mounting of keeper arms  18 ′ requires the further mounting of reinforcing bracket  60 . As discussed above, keeper arms  18 ′ include latch portions  22 ′ having a width, W′, which is wider than width W of latch portions  22  of keeper arms  18  (see  FIG. 1 ) generally by a distance D ( FIG. 4 ). When keeper arms  18 ′ are mounted within housing  12  of door strike  10 ′, the increased width W′ of latch portions  22 ′ in combination with the various forces imposed upon keeper arm  18 ′ by the door latch causes keeper arm  18 ′ to rotate and twist about pivots  20  within the x-y plane when the keeper arms are in the closed position and a force F′ is applied to latch portion  22 ′. This distortion generates unwanted torque upon keeper arm pivots  20 . Beyond potentially damaging keeper arms  18 ′ and keeper arm pivots  20 , latch portions  22 ′ may also not properly rotate about pivots  20  thereby preventing proper functioning of the door strike. 
         [0029]    To alleviate, and preferably eliminate, any distortion of keeper arms  18 ′ out of the x-y plane when in the closed position, reinforcing bracket  60  is mounted onto housing  12 . As seen most clearly in  FIGS. 5 and 6 , reinforcing bracket  60  has a thickness T selected to be substantially similar to distance D and generally comprises front bracket arms  60 A and bracket back  60 B joined at either end by integral sidewalls  60 C,  60 D. Reinforcing bracket  60  is configured to rest upon housing front wall  12 A, housing rear wall  12 B and cutout sidewalls  12 C,  12 D so as to further define cutout portion  14 . Reinforcing bracket  60  includes elbow regions  61  between arms  60 A and sidewalls  60 C,  60 D and hip regions  62  between sidewalls  60 C,  60 D and bracket back  60 B. Each elbow region  61  includes a respective downwardly extending finger  64 , while each hip region  62  includes a respective downwardly extending foot  66 . Fingers  64  are adapted to reside within figured recesses  21 A of keeper arm pivots  20 . Each foot  66  resides within a respective channel  15  disposed within cutout sidewalls  12 C,  12 D of housing  12 . Once properly seated in place, fingers  64 , feet  66  and bracket back  60 B secure reinforcing bracket  60  to housing  12  and prevent movement of bracket  60  in the x-z plane. A housing cover (not shown) is secured to housing  12  and prevents upward movement of bracket  60  in the y direction. 
         [0030]    With reinforcing bracket  60  secured in place within door strike  10 ′, latch portions  22 ′ are pivotally constrained within the x-y plane through bottom threaded post portion  23  of keeper arm pivot  20  and finger  64  of the reinforcing bracket. That is, keeper arms  18 ′ are supported both above and below the pivot point (i.e. shaft portion  25 ) rather than solely below the pivot point as shown in embodiment  10  ( FIGS. 1-3B ). This additional support minimizes the twisting moment (M) placed on the keeper arm pivots and enables proper operation of the wider latch portions  22 ′. 
         [0031]    While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.

Summary:
A reinforced door strike assembly comprises a housing having an opening for admission and retraction of a door latch. At least one keeper arm is movably attached to the housing, and movable between a closed position where the opening is occluded and an open position where the door latch may be released from the opening. A reinforcing bracket is mounted to the housing and further defines the opening. The reinforcing bracket is coupled to the at least one keeper arm and to the housing to hold the at least one keeper arm in a plane perpendicular to the plane of the housing.