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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to panels which are used to form garage doors wherein the various panel sections are hinged together to enable the garage door to rotate along tracks on either side of the garage door to be retracted adjacent the ceiling in order for the garage to be opened and then rotated back down so that the bottom of the entire garage door rests against the ground when the garage is closed. The present invention relates to the specific construction of the individual panels which are used to form the entire garage door. 
     2. Detailed Description of the Prior Art 
     To the best of the present inventor&#39;s knowledge, the prior art garage door panels which are related to the present invention are formed in the following way. They are known as sandwich doors which have a front skin usually made of 24 to 27 gauge steel and a rear skin also having 24 to 27 gauge steel and foam sandwiched between the two sections of steel. The foam material is expanded polystyrene E.P.S. and is usually 1⅞″ to two inches thick so that it is referred to as a two inch sandwich steel door. The length of the E.P.S. polystyrene is very important and it should be noted that it is as long as the door sections, i.e. 8 ft., 9 ft. 16 ft., 18 ft. etc. Full length solid pieces provide more strength than using multiple pieces in a section. The 2 inch sandwich steel door is the most widely used insulated door in the garage door industry. It should be noted that 1⅜″ thick steel sandwich doors are also used in the garage door industry. 
     A problem with the prior art garage door panels is that it is more expensive to have pre-painted steel on both the front and rear of the sandwich door assembly and when one panel is hinged to another panel, the panel hinges must necessarily be through the steel backing so that it is not visible from the outside. There is a significant need for an improved garage door panel where the cost of the manufacturing of the panel is reduced and where the unsightly hinge stile/hinge backup plate can also be concealed yet is retained in a strong manner so that it can enable one section to be rotated relative to a second section as the garage door is retracted and then returned to its position adjacent the ground. 
     It should be noted that currently manufactured poly/vinyl insulated doors are standard pan type. They are not insulated before assembly. They are post insulated with multiple pieces of pre-laminated E.P.S. sheet foam. This gives no strength to the door section. In addition to squeaking and loose fitting multi-piece construction, the unsightly door and hinge center support stiles are exposed. 
     Therefore, there is a need for an improved garage door assembly which addresses the above discussed problems. 
     SUMMARY OF THE INVENTION 
     The present invention is an improved sandwiched garage door panel. The first improvement is that the rear covering skin is made of 25 point embossed wood grain texture polyboard which is much less expensive than steel so that the cost of manufacture of the panel is significantly reduced. It should be noted that thicker or thinner polyboard could be substituted for manufacturing purposes. The second improvement is the 25 point woodgrain embossed polyboard which provides a significant weight reduction. Less total door weight allows for a reduction in spring size, door track and hinge thickness. This reduction allows for even more cost savings resulting in a less expensive insulated door. The third improvement is the creation of a channel within the central foam E.P.S. core of the panel with at least one, and preferably two, steel plates retained within the channel. As a result, a mounting plate of the hinge assembly which interconnects two adjacent panels can be affixed to the steel plate and thereafter the rear covering (25 point embossed wood grain texture polyboard) is bonded to the foam core to thereby conceal the mounting plate, resulting in a more attractive interior garage door panel. 
     It is therefore an object of the present invention to reduce the cost of the garage door panel and weight by replacing a rear steel covering skin with a 25 point embossed wood grain polyboard. 
     It is a further object of the present invention to provide a mechanism that runs the full height of the section, the mounting plate of the hinge assembly which interconnects two adjacent garage door panels that are concealed to thereby significantly improve the appearance of the inside of the garage door panel. 
     Further novel features and other objects of the present invention will become apparent from the following detailed description, discussion and the appended claims, taken in conjunction with the drawings. 
    
    
     
       DRAWING SUMMARY 
       Referring particularly to the drawings for the purposes of illustration only and not limitation therein is illustrated: 
         FIG. 1  is an exploded view of the present invention improved sandwich garage door panel illustrating the components of the sandwich door panel without the hinge assembly; 
         FIG. 2  is a perspective view of the assembled garage door panel with the back cover and end caps removed; 
         FIG. 3  is a perspective and partially exploded view illustrating the assembled garage door panel with the end caps removed; 
         FIG. 4  is a rear elevational view of the present invention garage door panel; 
         FIG. 5  is a rear elevational view of two adjacent garage door panels with the rear covers removed to illustrate the mechanism by which two panels are connected by hinges which are affixed to the interior middle sections within the channels of the foam core. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Although specific embodiments of the present invention will now be described with reference to the drawings, it should be understood that such embodiments are by way of example only and merely illustrative of but a small number of the many possible specific embodiments which can represent applications of the principles of the present invention. Various changes and modifications obvious to one skilled in the art to which the present invention pertains are deemed to be within the spirit, scope and contemplation of the present invention as further defined in the appended claims. 
       FIG. 1  is an exploded view of the present invention improved sandwich garage door. The entire assembly of the present invention garage door is labeled as  100 . The first section of the present invention garage door consists of a front steel skin  10  which is usually 24 gauge to 27 gauge steel. Because of the improvement as will be described in the present invention, the present invention can utilize 24 gauge to 27 gauge steel which is less expensive and lighter weight than 24 gauge steel. The front section  10  extends into an upper interlocking section  20  which consists of a first horizontal section  22 , a vertically orientated male interlocking section  24 , a second horizontal section  26  and then a lower vertically orientated rear section  28 . Rear section  28  extends to an inwardly facing horizontal surface  29 . The lower portion of the front steel skin extends into a lower interlocking section  30  which includes a first horizontal section  32 , a female interior section  34 , a second horizontal section  36  and then a lower vertical section  38  which is aligned and parallel to the upper vertical section  28 . Rear section  38  extends to an inwardly extending lower surface  39 . 
     The front steel surface  10  has a front surface  12  and a rear surface  14 . An interior gap or chamber  110  is located behind the rear surface  14  of front skin  10  and rests between the upper interlocking section  20  and the lower interlocking section  30 . Inserted into this gap is a 2 inch foam core  200  which by way of example can be made of expanded polystyrene EPS. By way of example only, the width “W” of the foam core can be approximately 2 inches. In prior art foam cores, the foam core consists of a solid rectangular piece of material. 
     An improvement of the present invention is to cut a lengthwise channel into the foam core. The foam core has a front side  210  which is smooth. The foam core has a first side wall  212  and a second opposed parallel side wall  214  which are also solid. The rear surface  220  has the improvement of the present invention. A channel  230  is formed in the rear surface  220  and extends from the top  240  to the bottom  250  of the foam core and extends inwardly for a depth “D” of approximately a quarter of an inch. The channel can have a width W 1  of anywhere from two inches to four inches. Inserted into the panel is a first rectangular piece of galvanized steel  300  which is shaped to fit within the channel  230  and extend from the top surface  240  to the bottom surface  250  of the foam. The rectangular piece of galvanized steel can by way of example be 24 gauge steel. Then inserted above the 24 gauge steel panel is a second galvanized steel panel  400  which also can be made of 24 gauge galvanized steel having a rectangular body  410  which terminates an upper transverse section  420  which extends perpendicular to the body  410  and a lower transverse section  430  which extends perpendicular to the body  410 . The rectangular plate  300  is placed into the channel  230  and then the second rectangular steel plate  400  is placed over the first rectangular steel plate so that the upper transverse section  420  is sandwiched between the top  240  of the foam core and the transverse upper interior surface  29  of the upper interlocking section or tongue and groove mating section  20  and the lower transverse section  430  of the steel plate is sandwiched between the bottom of the foam core  250  and the lower interior transverse surface  39  of lower interlocking section or tongue and groove section  30 . Because of the sandwiching effect, the metal plate  400  is firmly held against the interior plate  300  and also is firmly held within the foam core. 
     Referring to  FIG. 2 , there is illustrated the structure as just described in the assembled condition before the rear sheet is placed over back surface  220  of the foam core  200 . As illustrated in  FIG. 2 , the foam core  200  is sandwiched in the gap  110  and is press fit between the tongue and grove sections  20  and  30  and resting between the rear surface  14  of front steel plate  10  and between the interior of vertical surfaces  28  and  38  of respective tongue and groove sections  20  and  30 . Also illustrated is a lower section of a hinge assembly  500  which has a connecting plate  510  which is affixed to the metal plate  400  by various fastener members  520 ,  520   a , etc. which can be fastening screws which are fastened and screwed into the metal plate  400  and also extend to interior metal plate  300 . This is a significant improvement in the present invention because in the prior art, it was necessary to have the hinges affixed to the rear plates or front plates of the sandwich door sections where the plates were clearly visible. Through use of the present invention, the fastening portions of the hinge are concealed within the garage door panel because the hinge can be affixed to the center metal sections  400  and  300  in the center of the panel. After the hinge is affixed in this manner, another significant improvement of the present invention is the rear covering surface  50  of the present invention garage door assembly. In the prior art, the rear surface of the sandwich garage door also consisted of metal which included 24 gauge or 26 gauge steel. The innovation is that on the back section  50  of the sandwich door assembly  100  instead of a steel skin, the present invention substitutes therefore a composite which consists of 25 point embossed wood grain polyboard having a front surface  52  and a rear surface  54 . The front surface  52  of the polyboard  50  is laminated to the rear surface  220  of the foam with a PUR urethane or hot melt glue. Also, for purposes of security, the front surface  210  of the foam core  200  is also laminated to the interior surface  14  of the front steel skin  10  with PUR urethane. In the present invention, the rear polyboard  50  is laminated to the back of the surface  220  of the foam core  200  but does not extend over the rear surfaces  28  and  38  of the upper and lower tongue and groove sections. In the prior art, the steel skin did extend over these sections with a 90 degree bend. 
     The fully assembled panel is illustrated in  FIG. 3 . In addition to the foam core  200 , before final assembly, a lower foam core  260  is inserted into the lower channel of the lower tongue and groove section  30  and an upper foam core  270  is inserted into the upper tongue and groove section  20 . End cap  700  covers side  212  of foam core  200  and end cap  800  covers side  214  of foam core  200 . As a result, the panel is now completely enclosed but the improvements are that the hinge section is now concealed by the rear 25 point wood grain embossed poly board  50  of the present invention and the rear skin is much less expensive than using a steel skin as in the prior art. The rear surface of the completed garage door panel is illustrated in  FIG. 4  which shows that poly board  50  covers the rear of the panel but extend only up to the lower end of the vertical section  28  of the upper tongue and groove section  20  and the upper end of the vertical section  38  of the lower tongue and groove portion  30  of the garage door assembly  100 . 
     In operation, one panel is affixed adjacent another panel so that the male tongue portion  24  extends into the female groove portion  34  of an adjacent panel. The panels are hinged together. Referring to  FIG. 5 , there is shown a view with the rear surface of the panels removed for purposes of illustration to show how the hinge assembly is affixed from one panel to an adjacent panel. The hinge assembly  500  has the lower plate  510  as already discussed affixed by fastener members  520  and  520 A to the rear surface  410  of metal plate  400  and also through metal plate  300  of first or lower panel  100 A. The second or upper panel  100 B has the same construction as  100 A and the second portion of the hinge plate  530  is fastened to the rear surface  410 A of a rectangular metal plate and an interior plate of the upper panel  100 B by fastener members  540  and  540 A which also can be screws. After the rotatable hinge  560  is aligned at the intersection between the upper surface  26  of the lower panel and the lower surface  36  of the upper panel, that the tongue and groove assembly can fit so that the two panels are aligned when the garage door is in a vertical orientation and the door is in the closed position. The panels can rotate slightly relative to each other by means of the hinge  560  as the garage door rotates up a track to retract adjacent the ceiling for opening of the garage door. After the hinge assembly is assembled as illustrated in  FIG. 5 , the rear polyboard  50  assembly as illustrated in  FIGS. 3 and 4  is placed over the rear surface  220  of the foam and affixed thereto as previously discussed so that the connecting plates  510  and  530  of the hinge are concealed to make for a much more attractive appearance. 
     Therefore, through use of the present invention, the present invention has a rear surface having only a 25 point embossed wood grain polyboard which is therefore much less expensive than having a rear steel skin and also has an interior metal plate to which the hinge is fastened so that the hinge is concealed. 
     Of course the present invention is not intended to be restricted to any particular form or arrangement, or any specific embodiment, or any specific use, disclosed herein, since the same may be modified in various particulars or relations without departing from the spirit or scope of the claimed invention hereinabove shown and described of which the apparatus or method shown is intended only for illustration and disclosure of an operative embodiment and not to show all of the various forms or modifications in which this invention might be embodied or operated.

Summary:
An improved sandwiched garage door panel. The first improvement is that the rear covering skin is made of 25 point embossed wood grain polyboard which is much less expensive than steel so that the cost of manufacture of the panel is significantly reduced. The second improvement is the creation of a channel within the central foam core of the panel with at least one and preferably two steel plates retained within the channel. As a result, a mounting plate of the hinge assembly which interconnects two adjacent panels can be affixed to the steel plate and thereafter the rear covering plate is affixed to the foam core to thereby conceal the mounting plate resulting in a more attractive garage door panel.