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CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to and claims priority from U.S. Provisional Patent Application No. 61/781,933 filed Mar. 14, 2013. Additionally, this application is related to U.S. patent application Ser. No. 12/478,859 filed Jun. 5, 2009, now abandoned, and U.S. patent application Ser. No. 12/756,398, which issued as U.S. Pat. No. 8,627,630 on Jan. 14, 2014 and which are herein incorporated by reference in their entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention is particularly applicable to interior doors and will be described with particular reference thereto. However, it will be appreciated by those skilled in the art that the invention has broader applications and may also be adapted for use in exterior doors, tree house doors, or other door applications. It will also be appreciated by those skilled in the art that the invention has broader applications such as for allowing for the holding of inserts on or in any structure or device with a relatively planar surface. 
     It has been considered desirable to develop a door that has the ability to accept a number of different inserts to allow the door to have different functions by easily changing the insert; particularly, to allow the door to be changed between having a through viewing area and being fully enclosed for privacy. Additionally, it has been considered desirable to have doors that are designed to accept different inserts that also are designed to fit in a standard home interior door frame designed to hold a standard 1⅜-inch thick door where the door can fit into an existing doorway without on-site alterations to properly fit and be properly secured in a standard interior doorway. Additionally, it has been considered desirable to have an interior door designed to accept an array of different inserts that allow the door to have a change in its function, or designed to accept a combination of different inserts to provide a change in the function of the door that differs from the front of the door to the rear of the door. Additionally, it has been considered desirable to develop a door designed to be a standard door panel on one side and have the ability to accommodate an interchangeable insert to be installed on the opposite side. 
     Interior doors have many different methods of manufacture and are available with many different visual designs. Interior doors can be manufactured as a hollow core or solid core door. Hollow core doors often consist of a core of lattice or honeycomb made of corrugated cardboard, or thin wooden slats. They can also be built with staggered wooden blocks or staggered foam or cardboard spacers. The external shell (“skins”) of a hollow core door are either press-mold fabricated using compressed paper/wood bonded or hard plastic materials or other similar materials allowing for aesthetic designs such as panels; or fabricated with wood veneering giving the appearance of a flat wooden door. Compared to solid core doors, they are lighter, cost less to manufacture, durable (scratch resistant), and easier to install. Solid core interior doors are either manufactured from solid wood or medium density fiberboard (MDF) and are either fabricated with flat surfaces or patterned panel designs. 
     Accordingly, it has been considered desirable to develop a system, a kit, and a method to have the insert holding ability incorporated into an existing interior door design without significantly altering the door manufacturing methodology. Additionally, it has been considered desirable to develop a method to provide for the implementation of the insert holding ability into existing interior doors already installed into a home environment. It has been considered desirable to develop a modular system that has the ability to accept a number of different inserts to allow the system to have different functions by easily changing inserts that can be easily installed or applied to most existing door formats or surfaces with a relatively planar surface. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an insert holding system, a kit, and a method of installing the same. In several embodiments, the kit and/or system is constructed so that it can be installed in a standard interior door by modifying the existing door. In other embodiments, the insert holding system is installed in a door during the manufacturing of the door. The system and kit can also be configured to be installed in a wall, furniture, or another item or fixture. In several embodiments, the insert is constructed in a modular frame for easy replacement and exchange of the insert if damaged or if a different functionality is desired. For example, the insert could include a screen, a window, a mirror, a poster frame, a picture frame, a poster, a chalk board, a dry erase board, a cork board, or any combination thereof. In several embodiments, the insert can be installed or replaced without tools. The modular frame could hold one insert for display on one side of a door and hold another insert for display on the other side of the door. 
     In one embodiment, the present invention is an insert holding system including a modular housing defining a chamber, a substantially planar insert, the modular housing is configured to receive the substantially planar insert in the chamber; where the chamber of the modular housing is open at a first end and at a second end; and where the modular housing is configured to be disposed in an opening in a door or a planar surface. In another embodiment, the modular housing includes a first frame and a second frame, where the first frame is disposed at the first end of the chamber, and where the second frame is adapted to removably attach to the first frame at the second end of the chamber defining the chamber of the modular housing. In another embodiment, the insert holding system includes a mounting platform configured for receiving the modular housing, the mounting platform being further configured to mount into a through opening defined by a hollow core door, where the mounting platform is at least in part disposed in a cavity defined by the skin panels of the hollow core door, and where the mounting platform is fastened to the skin panels of the hollow core door. In another embodiment, the insert holding system includes a mounting platform formed integral with the modular housing forming an insert holding assembly, the insert holding assembly being formed from a plurality of sectional parts, the mounting platform being configured to mount into a through opening defined by a hollow core door, where the mounting platform is at least in part disposed in a cavity defined by the skin panels of the hollow core door, and where the mounting platform is fastened to the skin panels of the hollow core door. In another embodiment, the substantially planar insert includes a mesh screen. In another embodiment, the substantially planar insert includes a non-translucent insert, a mirror, a poster frame, a picture frame, a poster, a chalk board, a dry erase board, a cork board, or any combination thereof. In another embodiment, the substantially planar insert includes a section of translucent material. In another embodiment, the substantially planar insert includes a section of transparent material. In another embodiment, the substantially planar insert includes a plurality of layers of material. In another embodiment, the substantially planar insert is secured within the chamber by the second frame being attached to the first frame, by sliding the substantially planar insert and the first frame into the chamber without using a tool, and where the substantially planar insert and the second frame are removed from the chamber by sliding up and pulling out the second frame without using a tool. In another embodiment, the insert holding system is installed into a hollow core door including a first door panel on a first side of the hollow core door, a second door panel on a second side of the hollow core door, and an opening in the second door panel of the hollow core door on the second side, where the opening does not penetrate through the first door panel on the first side of the hollow core door. In another embodiment, the substantially planar insert includes a section of transparent material, such as glass, acrylic glass, or transparent polycarbonate, thus forming a window. 
     In another embodiment, the present invention is a kit for installing an insert holding system into a preexisting door. The kit includes a modular housing defining a chamber, a substantially planar insert, where the modular housing is configured to receive the substantially planar insert in the chamber, where the chamber of the modular housing is open at a first end and at a second end, and where the modular housing is configured to be disposed in an opening in a door. In another embodiment, the modular housing includes a first frame and a second frame, where the first frame is disposed at the first end of the chamber, and where the second frame is adapted to removably attach to the first frame at the second end of the chamber defining the chamber of the modular housing. In another embodiment, the kit further includes a mounting platform configured for receiving the modular housing, the mounting platform being further configured to mount into a through opening defined by a hollow core door, where the mounting platform is at least in part disposed in a cavity defined by the skin panels of the hollow core door, and where the mounting platform is fastened to the skin panels of the hollow core door. In another embodiment, the kit further includes a mounting platform formed integral with the modular housing forming an insert holding assembly, the insert holding assembly being formed from a plurality of sectional parts, the mounting platform being configured to mount into a through opening defined by a hollow core door, where the mounting platform is at least in part disposed in a cavity defined by the skin panels of the hollow core door, and where the mounting platform is fastened to the skin panels of the hollow core door. In another embodiment, the substantially planar insert includes a non-translucent insert, of any one of a mirror, a poster frame, a picture frame, a poster, a chalk board, a dry erase board, a cork board, and any combination thereof. In another embodiment, the substantially planar insert includes a section of transparent material, such as glass, acrylic glass, or transparent polycarbonate, thus forming a window. 
     In another embodiment, the present invention is a method of retrofitting a preexisting door with an insert holding system. The method includes the steps of removing a portion of the preexisting door thereby forming a void defined by the door, positioning a modular housing defining a chamber into the void, fastening the modular housing to the preexisting door, and where the modular housing is configured to receive a substantially planar insert in the chamber. In another embodiment, the modular housing includes a first frame and a second frame, where the first frame is disposed at the first end of the chamber, and where the second frame is removably attached to the first frame at the second end of the chamber defining the chamber of the modular housing. In another embodiment, the method further includes the steps of positioning a mounting platform configured for receiving the modular housing in a cavity defined by a plurality of skin panels of the preexisting door, and fastening the mounting platform to the plurality of skin panels of the preexisting door, where the preexisting door is a hollow core door. In another embodiment, the substantially planar insert includes a non-translucent insert, of any one of a mirror, a poster frame, a picture frame, a poster, a chalk board, a dry erase board, a cork board, or any combination thereof. In another embodiment, the substantially planar insert includes a section of transparent material, such as glass, acrylic glass, or transparent polycarbonate, thus forming a window. 
     It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments, of the invention; and together with the description serve to explain the principles and operation of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING(S) 
         FIG. 1  is a perspective view of an insert holding system kit made in accordance with the present invention; 
         FIG. 2A  is a front view of the upper left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 2B  is a bottom view of the upper left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 2C  is a top view of the upper left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 2D  is a left side view of the upper left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 2E  is a right side view of the upper left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 3A  is a front view of the upper right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 3B  is a bottom view of the upper right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 3C  is a top view of the upper right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 3D  is a right side view of the upper right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 3E  is a left side view of the upper right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 4A  is a front view of the lower left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 4B  is a bottom view of the lower left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 4C  is a top view of the lower left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 4D  is a left side view of the lower left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 4E  is a right side view of the lower left segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 5A  is a front view of the lower right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 5B  is a bottom view of the lower right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 5C  is a top view of the lower right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 5D  is a right side view of the lower right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 5E  is a left side view of the lower right segment of the modular insert holding frame shown in  FIG. 1 ; 
         FIG. 6A  is an interior side view of a side rail of the mounting platform shown in  FIG. 1 ; 
         FIG. 6B  is a front side view of a side rail of the mounting platform shown in  FIG. 1 ; 
         FIG. 6C  is a back side view of a side rail of the mounting platform shown in  FIG. 1 ; 
         FIG. 6D  is an end side view of a side rail of the mounting platform shown from the direction shown by directional arrow A in  FIG. 6B ; 
         FIG. 6E  is an end side view of a side rail of the mounting platform shown from the direction shown by directional arrow A in  FIG. 6B ; 
         FIG. 6F  is an end side view of a side rail of the mounting platform shown from the direction shown by directional arrow B in  FIG. 6B ; 
         FIG. 7A  is an interior top/bottom view of a top/bottom rail of the mounting platform shown in  FIG. 1 ; 
         FIG. 7B  is a front side view of a top/bottom rail of the mounting platform shown in  FIG. 1 ; 
         FIG. 7C  is a back side view of a top/bottom rail of the mounting platform shown in  FIG. 1 ; 
         FIG. 7D  is an end side view of a top/bottom rail of the mounting platform shown from the direction shown by directional arrow C in  FIG. 7C ; 
         FIG. 7E  is an end side view of a top/bottom rail of the mounting platform shown from the direction shown by directional arrow D in  FIG. 7C ; 
         FIG. 8  is back view of the modular insert retaining housing frame shown in  FIG. 1 ; 
         FIG. 9  is an exploded view of a spring of the modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 10  is close up views of an upper tab of the modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 11  is close up views of a lower tab of the modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 12  is an illustration of the installation of the knob of the modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 13A  is a back view of the segments of modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 13B  is a perspective view of the profile of a segment of modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 13C  is a side view of the profile of a segment of modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 14A  is a back view of the segments of modular insert housing frame shown in  FIG. 1 ; 
         FIG. 14B  is a perspective view of the profile of a segment of modular insert housing frame shown in  FIG. 1 ; 
         FIG. 14C  is a side view of the profile of a segment of modular insert housing frame shown in  FIG. 1 ; 
         FIG. 15A  is a close up front view of a lower tab of the modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 15B  is a close up side view of a lower tab of the modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 16A  is a close up front view of an upper tab of the modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 16B  is a close up side view of an upper tab of the modular insert retaining housing frame shown in  FIG. 8 ; 
         FIG. 17A  is an illustration of an installation method of the insert holding system during manufacturing of a hollow core door in accordance with the present invention; 
         FIG. 17B  is an illustration of an installation method of the insert holding system after manufacturing of a hollow core door in accordance with the present invention; 
         FIG. 17C  is an illustration of an installation method of the insert holding system in a solid core door in accordance with the present invention; 
         FIG. 17D  is an illustration of an installation method of the insert holding system in a hollow core door with only one opening in accordance with the present invention; 
         FIG. 17E  is an illustration of an installation method of the insert holding system, where the mounting platform is integral with the modular insert housing frame, in a hollow core door in accordance with the present invention; 
         FIG. 18A  is an illustration of a hollow core door that is constructed to accept an insert holding system made in accordance with the present invention; 
         FIG. 18B  is an illustration of another hollow core door that is constructed to accept an insert holding system made in accordance with the present invention; 
         FIG. 19  is an illustration of the steps of cutting and removing a section of a hollow core door in accordance with the present invention; 
         FIG. 20  is an illustration of the steps of installing a mounting platform in a hollow core door in accordance with the present invention; 
         FIG. 21  is an illustration of the steps of assembling the modular insert housing frame shown in  FIG. 1 ; 
         FIG. 22  is an illustration of the steps of installing the modular insert housing frame shown in  FIG. 1  in the opening of the door shown in  FIG. 19 ; and 
         FIG. 23  is an illustration of the steps of installing the insert and modular insert retaining housing frame shown in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed to an insert holding system, a kit, and a method of installing the same. 
     Referring to  FIGS. 1-23 , there is a shown insert holding system  10 , a kit  10  and a method of installing the same, the method being shown particularly in  FIGS. 19-23 . The insert holding system  10  includes a modular insert housing frame  12 , a mounting platform  14 , an insert  16 , and a modular insert retaining housing frame  18 . The modular insert housing frame  12  includes an upper left segment  20 , an upper right segment  22 , a lower left segment  24 , and a lower right segment  26 . These segments are configured for attachment to the mounting platform  14 , which includes side rails  28 , and top/bottom rails  30 . The modular insert housing frame  12  can also be directly installed into a properly cut opening in a solid core door as detailed below. 
     Referring more particularly to  FIGS. 2A-5E , details of the modular insert housing frame  12  are shown. The upper left segment  20 , the upper right segment  22 , the lower left segment  24 , and the lower right segment  26  include a plurality of predrilled holes  32  for fastening the segments to a decorative base frame, and a plurality of predrilled holes  34  for fastening the segments to the mounting platform  14 . The upper left segment  20  and the upper right segment  22  include upper cutouts  36  for receiving metal strips  38  to form upper slots  40 . The upper left segment  20  and the upper right segment  22  also include cutouts  42  for receiving rotatable tabs  44 . The cutouts  42  for receiving rotatable tabs  44  also include predrilled hole  46  for securing rotatable tabs  44 . The rotatable tabs  44  are complementing safety devices that aid a user by ensuring that the insert remains in place during the removal and installation of the modular insert retaining housing frame  18  by preventing gravity induced forward tilting movement when the rotatable tabs  44  are engaged. The lower left segment  24 , and the lower right segment  26  include lower cutouts  48  for receiving metal strips  38  to form lower slots  50 . The upper left segment  20 , the upper right segment  22 , the lower left segment  24 , and the lower right segment  26  include sizing portions  52 , which can be removed to adjust the size of the insert housing frame  12 . The sizing portions  52  may be partially precut or only marked with indicia to aid an installer in adjusting the size of the insert housing frame  12 . 
     Referring more particularly to  FIGS. 6A-6F , details of the side rails  28  of the mounting platform  14  are shown. The side rails  28  include an indented side seat  54  for the brackets  56  that secure the side rails  28  and top/bottom rails  30  together when installed in a hollow core door  58 . The side rails  28  also include predrilled screw holes  60  for attachment of the brackets  56 . Indicia arrows  62  indicate where nails  64  should be positioned and nailed when installing the side rails  28  into hollow core door  58 . The side rails  28  may also have a door knob cutout  66  to accommodate material reinforcing the area around the doorknob or hole for a doorknob of a hollow core door  58 . 
     Referring more particularly to  FIGS. 7A-7E , details of the top/bottom rails  30  of the mounting platform  14  are shown. The top/bottom rails  30  include an indented top/bottom seat  68  for the brackets  56  that secure the side rails  28  and top/bottom rails  30  together when installed in a hollow core door  58 . The top/bottom rails  30  also include predrilled screw holes  60  for attachment of the brackets  56 . Indicia arrows  62  indicate where nails  64  should be positioned and nailed when installing the top/bottom rails  30  into hollow core door  58 . 
     Referring more particularly to  FIGS. 8-13C , details of the modular insert retaining housing frame  18  are shown. The modular insert retaining housing frame  18  includes upper/lower frame segments  70 , and side frame segments  72 , which are secured together via frame brackets  74  and frame screws  76 . Frame cornering nails may be used as a substitution for securing the frame corners together. The modular insert retaining housing frame  18  further includes metal upper tabs  78 , flat springs  80 , and metal lower tabs  82 . Referring particularly to  FIG. 9 , the flat spring  80  is secured to the spring bracket  84 , and then secured to a lip  86  of the modular insert retaining housing frame  18  via spring screws  88  as illustrated by directional arrows  90 . Now referring particularly to  FIG. 10 , upper tab  78  is secured to a lip  86  of the modular insert retaining housing frame  18  via tab screws  92  as illustrated by directional arrows  90 . Now referring particularly to  FIG. 11 , lower tab  82  is secured to a lip  86  of the modular insert retaining housing frame  18  via tab screws  92  as illustrated by directional arrows  90 . Referring more particularly to  FIG. 12 , a brass knob  94  may be secured to the modular insert retaining housing frame  18  via tee nut  96  and machine screw  98 . The knob  94  is a complementing safety device that aids a user in ensuring that the modular insert retaining housing frame  18  remains seated in the insert housing frame  12  by preventing upward movement when engaged, which is detailed further below. 
     Referring more particularly to  FIGS. 14A-14C , the decorative base frame  100  of the modular insert housing frame  12  includes top/bottom frame segments  102  and side frame segments  104 . The top/bottom frame segments  102  and side frame segments  104  each include an attachment ridge  106  for lining up the attachment to the upper left segment  20 , the upper right segment  22 , the lower left segment  24 , and the lower right segment  26  of the modular insert housing frame  12 . While decorative base frame  100  does improve the aesthetics of the modular insert housing frame  12 , the decorative base frame  100  also serves to attach the upper left segment  20 , the upper right segment  22 , the lower left segment  24 , and the lower right segment  26  together via screw holes  32  when these elements are screwed together. 
     Referring more particularly to  FIGS. 15A and 15B , lower tab  82  includes holes  108  for receiving tab screws  92  and a curved projection  110  configured to be received in lower slots  50 . 
     Referring more particularly to  FIGS. 16A and 16B , upper tab  78  includes holes  108  for receiving tab screws  92  and a planar projection  112  configured to be received in upper slots  40 . 
     Referring more particularly to  FIGS. 17A-17E , while the above detailed description shows a particular embodiment, for implementing the present invention, there are other ways to the practice the present invention. The specific implementation chosen can be determined by the desired manufacturing methods and materials used. 
     Referring particularly to  FIG. 17A , the insert holding system  10  can be constructed in a hollow core door  58  during manufacturing of the door. In this embodiment, the mounting platform  14  is disposed between the first skin  114  and second skin  116  of the hollow core door  58 . The modular insert housing frame  12  with attached decorative base frame  100  is secured to the mounting platform  14  via predrilled holes  34  and attachment screw  118 . 
     Referring particularly to  FIG. 17B , the insert holding system  10  can be constructed in a hollow core door  58  after manufacturing of the door. In this embodiment, the mounting platform  14  is disposed between the first skin  114  and second skin  116  of the hollow core door  58 . The modular insert housing frame  12  with attached decorative base frame  100  is secured to the mounting platform  14  via predrilled holes  34  and attachment screw  118 . 
     Referring particularly to  FIG. 17C , the insert holding system  10  can be constructed in a solid core door  120  during or after manufacturing of the solid core door  120 . In this embodiment, no mounting platform is needed since the modular insert housing frame  12  with attached decorative base frame  100  is secured to solid core door  120  directly via predrilled holes  34  and attachment screw  118 . 
     Referring particularly to  FIG. 17D , the insert holding system  10  can be installed in a hollow core door  58  so that there is only an opening through the second skin  116  of the hollow core door  58 . In this embodiment, the mounting platform  14  is disposed between the first skin  114  and second skin  116  of the hollow core door  58 . The modular insert housing frame  12  with attached decorative base frame  100  is secured to the mounting platform  14  via predrilled holes  34  and attachment screw  118 . 
     Referring particularly to  FIG. 17E , the insert holding system  10  can be constructed in a hollow core door  58  so that the mounting platform  14  and modular insert housing frame  18  are combined to form an integrated platform  122 . In this embodiment, the integrated platform  122  is disposed between the first skin  114  and second skin  116  of the hollow core door  58 . The integrated platform  122  with attached decorative base frame  100  is secured directly to the first skin  114  and second skin  116  of the hollow core door  58  via nails, glue, or another fastener (not shown). 
     Referring particularly to  FIGS. 18A and 18B , the insert holding system  10  can be installed in either of the hollow core doors shown in  FIGS. 18A and 18B . The hollow core door  58  is shown with the first skin  114  removed to show the structure inside the hollow core door  58 . This door  58  includes a peripheral frame  124  which includes a top member  126 , a bottom member  128  and side members  130 . The door  58  further includes support blocks  132  and spine  134  to strengthen the door  58  and to make it more durable. The door  58  in  FIG. 18A , also has an inner peripheral frame  136  which includes a top inner member  138 , a bottom inner member  140 , and side inner members  142 . The mounting platform  14  of the insert holding system  10  is configured to attach to the above internal structures of a hollow core door  58  in addition to other typical arrangements known in the hollow core door arts. 
     Referring more particularly to  FIGS. 19-23 , a method of installing insert holding system  10 , or the insert holding system kit  10 , is illustrated. Referring to  FIG. 19 , a hollow core door  58  is provided, then a section  144  of the hollow core door  58  is cut and removed forming a through opening  146  in the hollow core door  58 . Now referring to  FIG. 20 , the mounting platform  14 , which includes side rails  28 , and top/bottom rails  30  is positioned between the first skin  114  and second skin  116  of the hollow core door  58 . The side rails  28  and top/bottom rails  30  should be placed serially in the door  58  one at a time in either a clockwise or counterclockwise order. Then the side rails  28  and top/bottom rails  30  are secured together via brackets  56  and bracket screws  148 . Next, the mounting platform  14  is secured to the door  58  via nails  64 . 
     Now referring to  FIG. 21  which shows the assembling of the modular insert housing frame  12 . The top/bottom frame segments  102  and side frame segments  104  of the decorative frame  100  are positioned together then attached to the upper left segment  20 , the upper right segment  22 , the lower left segment  24 , and the lower right segment  26  of the modular insert housing frame  12  via screw holes  32  and frame screws  150 . The metal strips  38  are then secured to upper cutouts  36  via accessory screws  152  to form upper slots  40 . Next the metal strips  38  are then secured to lower cutouts  48  via accessory screws  152  to form lower slots  50 . Then rotatable tabs  44  are secured within cutouts  42  via predrilled hole  46  and accessory screws  152 . The modular insert housing frame  12  may then be further reinforced by securing support bar  154  to the upper left segment  20  and the upper right segment  22  via accessory screws  152 . 
     Now referring to  FIG. 22 , the modular insert housing frame  12  is then positioned in the through opening  146  and secured to the mounting platform  14  via attachment screws  118  being screwed through predrilled holes  34 . 
     Now referring to  FIG. 23 , the planar insert  16  can be placed within the chamber  156  defined by the modular insert housing frame  12 . Then, rotatable tabs  44  can be moved to maintain the insert within the chamber  156 , while a user obtains the modular insert retaining housing frame  18 . The insert retaining housing frame  18  is coupled to the modular insert housing frame  12  without tools by sliding upper tabs  78  into upper slot  40  and by pushing up to compress springs  80 . Then the bottom of the insert retaining housing frame  18  is swung towards the bottom of the modular insert housing frame  12  so that insert retaining housing frame  18  touches or applies pressure to the insert  16  and the lower tabs  82  are just above lower slots  50 . The user then lets the modular insert retaining housing frame  18  slide down so that lower tabs  82  are received in lower slots  50 , thereby securing the modular insert housing frame  12 , the insert  16 , and the insert retaining housing frame  18  are secured together. Similarly, the insert retaining housing frame  18  is removed from the modular insert housing frame  12  by sliding the insert retaining housing frame  18  up and swing the bottom of the insert retaining housing frame  18  out. Then moving the rotatable tabs  44  and removing the insert from the chamber  156 . 
     The components of the insert holding system  10  and the insert holding system kit  10  can be constructed from any suitable material or combinations of materials. It is specifically envisioned that the above components are constructed from a plastic, a polymer, a wood, a fiber board, a particle board, a fiberglass, or any combination thereof. The above components can also be delivered to a user completely or partially assembled to aid in the installation of the components. It should also be clear that an entire door  58  can be manufactured with the insert holding system  10  and provided to the user, which can be installed in a doorway in the same fashion as a door without the insert holding system  10 . 
     The advantages of the present invention include a method for having the insert holding system applied to any type of door without the door being substantially modified in its method of construction. It also allows for the Insert Hold System to be easily incorporated into existing doors that are already installed in a home where the home owner or resident is the installer of the “conversion kit”. This design delivers all of the necessary precision parts as a “retrofit package” greatly simplifying the incorporation of the invention to commercially available and/or existing already installed doors, and/or any relatively planner surface; thus, increasing the commercial application of the invention. Likewise, delivering the aspects of the insert holding system using the methods described in this application significantly reduces the factory retooling necessary for its use in door products. Regarding the through-opening version, this design also has the ability of being interchanged from one side of the door to the other; thus, allowing the removable frame to be switched in its choice of side to be attached. The design of this insert holding system is such that it fits solid core door, and also fits hollow core doors with the addition of the mounting platform. 
     While a presently preferred and various alternative embodiments of the present invention have been described in sufficient detail above to enable a person skilled in the relevant art to make and use the same, it should be obvious that various other adaptations and modifications can be envisioned by those persons skilled in such art without departing from either the spirit of the invention or the scope of the appended claims.

Summary:
The present invention is directed to an insert holding system, a kit, and a method of installing the same. In several embodiments, the kit and/or system is constructed so that it can be installed in a standard interior door by modifying the existing door. In other embodiments, the insert holding system is installed in a door during the manufacturing of the door. The system and kit can also be configured to be installed in a wall, furniture, or another item or fixture. In several embodiments, the insert is constructed in a modular frame for easy replacement and exchange of the insert, if damaged, or if a different functionality is desired. For example, the insert could include a screen, a window, a mirror, a poster frame, a picture frame, a poster, a chalk board, a dry erase board, a cork board, or any combination thereof.