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BACKGROUND  
         [0001]    This invention relates generally to door and window frames, and more specifically to prefabricated casing and molding structures for doors and window frames.  
           [0002]    Metal frames and moldings for doors and windows have been widely used for some time, and were originally described in U.S. Pat. No. 3,107,759 entitled PREFABRICATED DOOR FRAME AND MOLDING STRUCTURE, which issued on Oct. 22, 1963 to Robert L. Day and Harry L. Williams. These popular moldings, also commonly known and referred to hereinafter as casings, are pre-fitted and pre-manufactured at a factory as individual pieces that are later assembled at a construction site.  
           [0003]    Current casing structures have corner connectors that are intended to hold the mitered corners together. However, the effectiveness of these prior art corner connectors is compromised because they are designed to be reversibly attached to the casing pieces to allow the structure to be adjusted upon assembly. A resulting problem is that the individual casing pieces of the structure can become separated at corners over time and repeated use.  
           [0004]    One particular problem is that the vertical casing members tend to move downward with time due to the effect of gravity, building settling, and repeated and prolonged door closings. This causes the mitered corners formed by the abutment of two casing members to separate. As individual casing pieces move from their original intended position, the integrity of the entire casing structure is weakened because adjacent casing members help sustain the position of one another.  
           [0005]    What is needed is casing structure that is pre-manufactured, adjustable, and yet can be assembled to provide a unitary casing structure that does not disengage or separate at corners over time and prolonged usage.  
         SUMMARY  
         [0006]    The invention satisfies this need. The invention is a casing assembly for a wall opening that, upon assembly, provides a unitary casing structure that does not disengage or separate at corners over time and prolonged usage. The casing assembly of the invention also retains the benefits of prior art casing assemblies in that it is pre-manufactured and is adjustable.  
           [0007]    The casing assembly comprises a plurality of casing members to be interconnected to form a framed casing having at least one corner. The casing members are channel shaped, and have a casing surface wall connected to two opposed casing side walls. Each casing member has two opposed open ends. The casing assembly further comprises at least one corner connector. Each corner connector comprises two male connectors that are disposed at about a 90 degree angle to one another. The male connector is configured to engage with and plug into one of the open ends of the casing members. The casing assembly further comprises attachment means for fixedly attaching at least one male connector in one of the open ends of one of the casing members before the casing members are assembled together. The attachment means prevents the casing members from disengagement after assembly.  
           [0008]    In another embodiment, the invention is a unitized casing assembly for a wall opening wherein the above described casing members are attached to frame members. The frame members are interconnected and attached to a wall opening having at least three longitudinal edges. The frame members comprise a jamb surface wall having two opposing lateral edges. Each lateral edge of the jamb surface wall is interconnected to a frame side wall at about a 90 degree angle. Each frame side wall is configured to lie flat along a surface adjacent to a wall opening. The frame member side walls have integral clip holders that are spaced apart a predetermined distance from the lateral edge of the jamb surface wall. The unitized casing assembly further comprises a series of casing clips that upon assembly fit into and are rigidly secured by the clip holders. The casing members are then attached to a frame side wall by the casing clips. Upon assembly, the attachment of corner connectors to casing members by the attachment means maintains the position of the casing members along an axis parallel to the longitudinal wall opening edge. The casing clips maintain the position of the casing members in an axis perpendicular to the longitudinal wall opening edge. The attachment means and the casing clips, in combination, provide a unitized casing assembly that is substantially free from disengaging at the corners and a casing assembly that is rigid disposed relative to the wall opening. 
       
    
    
     DRAWINGS  
       [0009]    These features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims and accompanying figures where:  
         [0010]    [0010]FIG. 1 is a perspective view a framed casing according to the present invention shown assembled in a door opening;  
         [0011]    [0011]FIG. 2 is an enlarged perspective view of the framed casing of FIG. 1;  
         [0012]    [0012]FIG. 3 is a perspective view of a corner connector according to the present invention;  
         [0013]    [0013]FIG. 4 is a perspective view of a corner connector according to the present invention shown in engaging alignment with two casing members;  
         [0014]    [0014]FIG. 5 is a perspective view of a corner connector according to the present invention shown plugged into a casing member and fixedly attached to the casing member by crimps in the casing member;  
         [0015]    [0015]FIG. 6 is a perspective view of a corner connector according to the present invention shown with one male connector plugged into a casing member and the other male connector shown in engaging alignment with a second casing member;  
         [0016]    [0016]FIG. 7 is a perspective view of a unitized casing assembly according to the present invention shown partially assembled;  
         [0017]    [0017]FIG. 8 is a cross-section of the corner connector and casing member of FIG. 5 taken along line  8 - 8  in FIG. 5;  
         [0018]    [0018]FIG. 9 is a perspective view of an embodiment of a corner connector of the present invention having a dimpled depression;  
         [0019]    [0019]FIG. 10 is a perspective view of the corner connector of FIG. 9 shown with one male connector engaging with a casing member and the second male connector in alignment with a second casing member;  
         [0020]    [0020]FIG. 11 is a perspective view of a corner connector mounted in a corner of a casing assembly according to the present invention shown; and  
         [0021]    [0021]FIG. 12 is a cross-section of the corner connector of FIG. 11, taken along line  1212 . 
     
    
     DESCRIPTION  
       [0022]    The following discussion describes in detail two embodiments of the invention and several variations of these embodiments. This discussion should not be construed, however, as limiting the invention to those particular embodiments. Practitioners skilled in the art will recognize numerous other embodiments as well. In all of the embodiments described herein that are referred to as being preferred or particularly preferred, these embodiments are not essential even though they may be preferred.  
         [0023]    The invention is a casing assembly  10  for a wall opening  12  comprising a plurality of casing members  14  that are interconnected at corners  16  by corner connectors  18  to form a framed casing  20 .  
         [0024]    The framed casing  20  has at least one corner  16 . In the embodiment illustrated in FIG. 2, the framed casing  20  has two corners  16  on each surface of the wall opening  12 . In the embodiment illustrated in FIG. 1, the casing assembly  10  comprises a header casing member  14  and two vertical casing members  14 . Upon assembly, the header casing member  14  is disposed horizontally and each vertical casing member  14  is connected to the header casing member  14  at a corner  16 . In alternative embodiments (not shown), the framed casing  20  is configured to mount into a window opening and the framed casing  20  has four corners  16  on each side of the wall opening  12 . In still alternative embodiments (not shown), the framed casing  20  is configured to mount into a door or window opening with one or more sidelites or partial sidelites, and the framed casing  20  comprises six or more corners  16  on each side of a wall opening  12 .  
         [0025]    As shown in the embodiment in FIG. 8, each casing member  14  is generally channel shaped and comprises a casing surface wall  22  connected to two opposed casing side walls  24 . The casing members  14  have an inner channel surface and an outer surface. The casing surface wall  22  of each casing member  14  has two opposed lateral edges. In the embodiments illustrated in the drawings, the casing surface wall  22  is substantially planar and generally rectangular. In alternative embodiments (not shown), the casing surface wall  22  is not entirely planar and the casing members  14  have a beveled, molded, or otherwise decorative shaped surface. The term casing members  14  as used herein includes molding, trim, and similar such articles. The casing members  14  are typically formed of wood, plastics, and metals such as aluminum, brass, steel, and alloys. In a preferred embodiment, the casing members  14  are made from cold rolled steel sheet metal. The casing members  14  can be coated with a decorative finish such as, for example, a baked enamel.  
         [0026]    Each casing side wall  24  of a casing member  14  has a connecting edge  26  and a free edge  28 . As illustrated in FIG. 8, each lateral edge of the casing surface wall  22  is interconnected or attached with the connecting edge  26  of a casing side wall  24 . In the embodiments illustrated in the drawings, each side wall  24  of the casing members  14  further comprises a rim  30 . As illustrated in FIGS. 4, 5,  6 , and  8 , each rim  30  is attached to and interconnected with the free edge  28  of a casing side wall  24 , and each rim  30  is disposed in a plane that is substantially in parallel to the plane of the casing surface wall  22  of that particular casing member  14 .  
         [0027]    As illustrated in FIG. 1, each casing member  14  has two opposed open ends  32 . In preferred embodiments, an open end  32  from at least two separate casing members  14  is mitered at an angle. In embodiments having mitered open ends  32 , the abutting open ends  32  are mitered at angles to cooperate with one another to form a corner  16  having a desired angle. Typically the open ends  32  to be in abutment are mitered at and angle of between about 30 degrees and about 60 degrees, and when abutted together the two casing members  14  form a 90 degree corner  16 . In preferred embodiments, the open ends  32  of at least two casing members  14  are mitered at an angle of about 45 degrees such that upon assembly and abutting the two together they form a 90 degree corner  16 . For example, a casing assembly  10  for a framed door opening has two vertical casing members  14  and the open end  32  of the vertical casing member  14  which is upwardly disposed is mitered but the downwardly disposed open end  32  is not mitered, and in contrast the horizontally disposed header casing member  14  is mitered at both open ends  32 .  
         [0028]    The casing assembly  10  further comprises at least one corner connector  18 . With reference to FIGS.  3 - 5 , each corner connector  18  comprises two male connectors  34  that are disposed at about a 90 degree angle relative to one another. Each male connector  34  is configured to engage with and plug into one of the open end  32  of the casing members  14 . In the embodiment of the corner connector  18  illustrated in FIGS.  3 - 6 , each male connector  34  comprises three interconnected connector surface walls that are configured to slidably engage with the casing surface wall  22  and opposed casing surface walls  22  of a casing member  14  when a male connector  34  is plugged into an open end  32  of a casing member  14 .  
         [0029]    With reference to the embodiment of the corner connector  18  illustrated in FIGS. 4 and 5, each male connector  34  comprises a connector bottom wall  36 , a first male connector side wall  38 , and a second male connector side wall  38 . The connector bottom wall  36  comprises two lateral edges. Each male connector side wall  38  comprises a connecting edge  40  and a free edge  42 , with the connecting edge  40  of the first male connector side wall  38  being connected to one lateral edge of the connector bottom wall  36  at about a 90 degree angle, and the connecting edge  40  of the second male connector side wall  38  being connected to the other lateral edge of the connector bottom wall  36  at about a 90 degree angle.  
         [0030]    The casing assembly  10  further comprises attachment means  44  for fixedly attaching at least one male connector  34  in one of the open end  32  of one of the casing members  14  before the casing members  14  are assembled. The attachment means  44  functions to prevent the casing members  14  from disengagement at abutted corners  16 . In the embodiment illustrated in FIG. 5 and FIG. 8, the side walls of the molding members have rims  30  and the attachment means  44  comprises at least one crimp  44  on a rim  30  that presses against a male connector  34  plugged into an open end  32 . The at least one crimp  44  acts to fixedly attach the male connector  34  in the open end  32 . In alternative embodiments (not shown), the attachment means  44  comprises other forms of attachment such as attachment of a casing member  14  to a corner connector  18  by spot welding or soldering, attachment of a casing member  14  to a corner connector  18  with a glue or adhesive, by compression of a portion of a molding member against a corner connector, or by riveting.  
         [0031]    In a preferred embodiment, the casing members  14  are interconnected to form a framed casing  20  wherein only one male connector  34  of each corner connector  18  is fixedly attached to an open end  32  of a casing member  14 . In another preferred embodiment, a first male connector  34  of a corner connector  18  is plugged into an open end  32  of at least one vertical casing member  14  and fixedly attached in the open end  32  of the vertical casing member  14  prior to plugging the second male connector  34  of the corner connector  18  into a horizontal casing member  14  and prior to completing assembly of the casing assembly  10 .  
         [0032]    In the embodiment illustrated in FIGS.  9 - 12 , the corner connector  18  further comprises a dimpled depression  46 . The dimpled depression  46  abuts against two casing member surface walls  22  when the male connectors  34  of a corner connector  18  are plugged into the open ends  32  of two casing members  14  at a corner  16 .  
         [0033]    With reference to FIGS. 1 and 7, another embodiment of the invention is a unitized casing assembly  10  for a wall opening  12 . The unitized casing assembly  10  comprises frame members  48  that are interconnected in a wall opening  12  and attached to the wall opening  12 . The wall opening  12  comprises at least three longitudinal edges. A wall opening  12  for a door has three longitudinal edges, two being vertical and one being horizontal. A wall opening  12  for a window typically has four longitudinal edges, two being vertical and two being horizontal. A wall opening  12  for a door or window having a sidelite will have a number of additional longitudinal edges that depends on the particular configuration.  
         [0034]    Each frame member  48  comprises a jamb surface wall  50  having two opposing lateral edges. Each lateral edge of a jamb surface wall  50  is interconnected to a frame side wall  52  at about a 90 degree angle. As illustrated in FIG. 1, each frame side wall  52  is configured to lie flat along a wall surface adjoining a wall opening  12 .  
         [0035]    As illustrated in FIG. 7, the frame side walls  52  comprise clip holders  54  that are integral with the frame side wall  52 . Preferably, the clip holders  54  are spaced apart a predetermined distance from the lateral edge of the jamb surface wall  50 . The clip holders  54  are configured to hold a series of casing clips  56  that are fitted into the clip holders  54  and rigidly secured to the clip holders  54 .  
         [0036]    The casing members  14  are attached to the frame side walls  52  by engagement with the casing clips  56 . Typically the casing members  14  are disposed and attached substantially in-parallel to the longitudinal axis of a frame member  48  that is disposed in-parallel to a proximal wall opening  12  edge. The casing clips  56  have rounded ends that facilitate the engagement of the casing members  14  with the casing clips  56  upon assembly. The casing clips  56  are configured to have a width substantially similar to the width of the casing members  14  such that, upon assembly, they firmly press against the inner surface of the casing member  14 .  
         [0037]    The casing clips  56  maintain the position of the casing members  14  in an axis perpendicular to the longitudinal wall opening  12  edge. The casing clips  56  also provide some degree of positional maintenance to the casing members  14  along an axis parallel to the longitudinal wall opening  12  edge, but not enough to prevent the casing members  14  from moving or sliding in either direction parallel to the longitudinal wall opening  12  edge if sufficient force is applied.  
         [0038]    The problem of separation of mitered corners  16  is solved by the attachment means  44 . The attachment means  44  functions to fixedly attach a male connector  34  in one of the open end  32  of a casing member  14  before the casing members  14  are assembled. The attachment means  44  maintains the position of the casing members  14  along an axis parallel to the longitudinal wall opening  12  edge and prevents the casing members  14  from disengaging upon assembly. The attachment means  44  and the casing clips  56  function synergistically to provide a unitized casing assembly  10  that is firmly supported in horizontal and vertical direction. The attachment means  44  and casing clips  56 , when functioning together, also firmly retain the casing assembly  10  in all directions relative to the plane of the wall opening  12 .  
         [0039]    The invention further includes a method of forming a framed casing  20  comprising the steps of selecting a casing assembly  10  described herein; plugging a male connector  34  into an open end  32  of a casing member  14 ; fixedly attaching the male connector  34  within the casing member  14 ; and assembling together the casing members  14  so they do not disengage from each other. A particularly preferred method according to the invention further comprises the steps of selecting a casing assembly  10  having at least two separate casing members  14  that are mitered at an angle of about 45 degrees, after plugging a male connector  34  into a vertical casing member  14 , fixedly attaching the corner connector  18  in the vertical casing member  14 ; and assembling together the casing members  14  such that the mitered corners  16  are held together tightly in a fixed position relative to each other.  
         [0040]    In installing a typical casing assembly  10 , the components such as the casing members  14 , frame members  48 , and corner connectors  18 , are pre-fitted and pre-manufactured at a factory and brought to the assembly site. The casing members  14  are fixedly attached to the corner connectors  18  by the attachment means  44 , either on site or at the factory. In the preferred embodiment, in which the open end  32  are mitered, it is important that the corner connectors  18  are plugged into the open end  32  a suitable distance to ensure a tight miter before attachment by the attachment means  44 . After the wall opening  12  has been inspected to verify that the opening sizes and wall thicknesses are acceptable, the frame members  48  are fitted, aligned, and anchored in the wall opening  12 . Where the assembly is for a door frame, the upper horizontal casing member  14  is first attached to the horizontal frame member by pressing or popping the casing member  14  onto casing clips  56  that have previously been attached to the frame member. The vertical casing members  14 , which have a corner connector  18  attached to their upper open end  32  by the attachment means  44 , are pulled a slight distance away from the casing clips  56  protruding from the horizontal frame members  48 , and simultaneously plugged into the open end  32  of the horizontal header casing member  14 .  
         [0041]    Having thus described the invention, it should be apparent that numerous structural modifications and adaptations may be resorted to without departing from the scope and fair meaning of the instant invention as set forth hereinabove and as described hereinbelow by the claims.  
         [0042]    Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. For example, although the attachment means  44  typically comprises crimping, other attachment means such as welding, soldering, adhesives, by compression, or riveting may be substituted. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions described herein.  
         [0043]    All features disclosed in the specification, including the claims, abstracts, and drawings, and all the steps in any method or process disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in the specification, including the claims, abstract, and drawings, can be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.  
         [0044]    Any element in a claim that does not explicitly state “means” for performing a specified function or “step” for performing a specified function, should not be interpreted as a “means” or “step” clause as specified in 35 U.S.C. §112.

Summary:
The invention is a is a pre-manufactured casing assembly for a wall opening that is assembled to form a unitary casing structure that does not disengage or separate at corners over time and prolonged usage. The corners of the casing assembly are rigidly held in place by corner connectors that are attached to the individual casing pieces by attachment means.